Kerry Slug
Encyclopedia
The Kerry slug or Kerry spotted slug, scientific name Geomalacus maculosus, is a rare species
of medium-sized to large air-breathing land slug
. It is a terrestrial
pulmonate gastropod mollusc in the family Arionidae
, the roundback slugs.
An adult Kerry slug generally measures 7–8 cm (2.8–3.2 in) in length and is dark grey or brownish in colour, with yellowish spots. The internal anatomy of the slug shows some unusual features, and some characteristic differences from the genus Arion, which is the type genus of the family Arionidae. The Kerry slug was described in 1843, rather late compared to many other relatively large land gastropods that form a part of the fauna of the British Isles
; this is one indication of this slug's rarity and its secretive habits.
Although the distribution of this slug species does include some wild habitats in southwestern Ireland
(e.g. in County Kerry
), the species is more widespread in north-west Spain
and from central to northern Portugal
. However, it is not found anywhere between Ireland and Spain. The species appears to require environments that have high humidity and acidic soil (soil with no calcium carbonate
in it). The slug is mostly nocturnal or crepuscular
, although in Ireland it is active on overcast
days. It feeds on lichens, liverwort
s, moss
es and fungi, which grow either on boulders or on tree trunks.
This rare species is officially protected by conservation
laws in each of the three countries in which it occurs. However, the survival of the Kerry slug is nonetheless threatened because it lives only in completely wild, unspoiled habitat of a particular type: acidic woodland
s and moorland
s that support the species of lower plants on which the slug relies for food. This habitat type is itself at risk from a number of different factors, ranging from climate change
to the construction of roads. Attempts have been made to establish breeding populations in captivity
, to help ensure the survival of this slug species, but with only limited success.
s and slugs, including slugs and snails that live in saltwater, those that live in freshwater, and those that live on the land. This is a land slug which breathes air, a pulmonate. It is in the clade Stylommatophora
, which means that its primitive eyes or eye spots are carried on the tips of its two upper tentacle
s. Despite superficial similarities, not all land slugs are in the same family or superfamily. The Kerry slug is an arionid, or round-backed slug; it has no keel
on its back, in contrast to the land slugs in the family Limacidae
and Agriolimacidae
. It also shares numerous internal anatomical features with slug species in other genera within the family Arionidae
, including the Arion slugs, which are most typical of the family.
The Kerry slug's scientific name or binomial name is Geomalacus maculosus. It is in the genus Geomalacus, a name which literally means "earth mollusc". Its specific name maculosus means "spotted", from the Latin word macula "spot". The English language vernacular
name (or common name
) is derived from the name of County Kerry, which is the county in the southwest of Ireland where this species was first collected, and the type locality which is mentioned in the original description.
The scientific name of the species is also sometimes written as Geomalacus (Geomalacus) maculosus. This is because the genus Geomalacus contains two subgenera: the nominate subgenus (subgenus of the same name) Geomalacus and a second subgenus Arrudia Pollonera, 1890. The subgenus Geomalacus contains only one species, the Kerry slug. The subgenus Arrudia includes three species.
This slug species was originally described and named from specimens collected in Ireland. In 1842, an Irish naturalist named William Andrews (1802–1880) sent material that he had found at Caragh Lake
in County Kerry
to the Irish naturalist
George James Allman
, who then introduced the slug to science as a new species.
Kerry slug has been included in molecular phylogenetic studies since 2001.
(see the section entitled behaviour). Kerry slugs can also elongate themselves within crevices up to 12 cm (4.8 in). "Official" measurements of this species vary, for example, Kerney et al. (1983) give slightly different measurements for the species: 6–9 cm (2.4–3.6 in). The body of a fixed (preserved) adult specimen was 7 cm (2.8 in) long with a mantle
length of 3 cm (1.2 in).
The body of these slugs is glossy, and is covered on the left and right sides with about 25 longitudinal rows of polygonal granulations (very small knobs with outlines like polygons). These slugs are usually blackish or dark-grey in colour, sometimes with indistinct darker bands. On each side of the body there can be two bands: one band just below the summit of the back, and the other band further down the side of the body. When these bands are present they usually extend the whole length of the body of the slug, and are overspread by numerous, somewhat oval, yellowish spots. These yellow spots are distributed more or less in five longitudinal zones.
Behind the animal's head, the "shield" (the shield-shaped outer surface of the mantle
) is about a third of the length of the body when the slug is actively crawling and thus extended, but only about half of that when the slug is motionless and contracted. The shield is rounded in front and bluntly pointed behind. The texture of the surface of this area resembles the underside of untanned leather. It is spotted with pale buff or whitish spots similar to those on the body, but more uniformly distributed.
The foot-fringe (a band of tissue around the edge of the foot) is not very distinctly separated: it is very pale and somewhat expanded, with indistinct lines on it. The sole of the foot is pale grayish yellow in colour, and is divided into three indistinct bands, with the mid-area being somewhat darker and more transparent than the sides. There is a caudal mucous pit
situated between the foot and the body on the upper surface of the tip of the tail
. The pit (which collects extra mucus) is not very conspicuous, but it is triangular in shape and opens transversely (i.e. from side to side). The mucous pit often carries a transparent yellowish ball of slime (mucus).
The upper tentacle
s are smoky-black or grey, short and thick, with oval ends, and have the usual eye spots at their tips. The genital pore (or opening) lies behind and below the right eye-tentacle. The lower tentacles are pale translucent grey. The skin mucus is usually pale yellow, and varies in its degree of viscosity (stickiness). The locomotory-mucus (mucus for crawling on) is tenacious and usually colourless, but it can be yellowish because of having mixed with the body slime.
, and this exists either in the form of an internal shell (a thin shelly plate), or a collection of shelly granules. In this species there is an internal shell or shell plate which resembles that found in land slugs of the genus Limax
. In other words, the shell plate in this species is oval in shape, solid and calcareous
(chalky), with a transparent conchiolin
(horny) base. It is usually somewhat convex above and concave beneath, with a few indistinct concentric lines of growth, and is covered outwardly with a very thin transparent periostracum
(a protein layer), and with the nucleus (the oldest growth part) near the front. In young animals, the shell is very thin and convex, abruptly cut off behind, but with an extremely thin layer that projects in front and contains minute granules.
The drawing of the shell can slightly differ in various authors showing, that it is just a solid plate:
and excretory system
are closely related, in that the heart is surrounded by the triangular kidney
. The kidney has a lamellate (layered) structure and it has two ureter
s. In this slug species, the ventricle
of the heart is directed towards, and is very close to, the anal
and respiratory openings. The ventricle of the heart is further away and further back than it is in species of the related genus Arion
, the type genus of the family Arionidae.
The gland above the foot, the suprapedal gland
, is deeply imbedded in the tissues, and reaches far back. The cephalic (head) gland known as the Semper's organ
is well developed, and shows as a pair of strong flattened lobes. The salivary
and digestive glands are the same as those found in Arion species, but the vestigial osphradium
(kidney-like structure) within the mantle
chamber is more distinct than it is in Arion species.
as all other pulmonates. Its reproductive system
is diagnostic feature. Genus Geomalacus
has a special feature: the atrium has diverticulum. This atrial diverticulum is elongated part of the atrium. Penis in the genus Geomalacus is reduced and lost as well its penial retractor muscle. Atrial diverticulum is secondary penial structure and with its spermatheca retractor muscle atrium acts as a copulatory organ instead. The second end of the spermatheca retractor muscle extends into posterior end of the body. Atrial diverticulum is morphological equivalent (analogy
, homoplasy) of penis.
Geomalacus maculosus has atrial diverticulum longer than spermatheca duct, while Geomalacus anguiformis
has atrial diverticulum shorter than spermatheca duct.
Various authors have depicted the reproductive system of Kerry slug: Godwin-Austen
(1882), Sharff (1891), Simroth (1891, 1894), Taylor (1907), Germain (1930), Quick (1960) and Platts & Speight (1988). Platts & Speight (1988) consider from previous authors depiction by Godwin-Austen (1882) to be the most accurate, because other authors depicted atrium too short.
The Kerry slug's reproductive organs are as follows: there is a small, compact, and darkly pigmented ovotestis
(a combination of ovary and testis). There is a hermaphroditic duct (male and female duct) which is very long and greatly convoluted, and ends in a small spherical vesicula seminalis (seminal vesicle). The albumen gland (which creates albumen for the eggs) is elongated and shaped like a tongue. The ovispermatoduct (a duct that carries both eggs and sperm) is very much twisted. The free oviduct (duct that carries eggs only) is rather long and thin, but without any enlargement.
The vas deferens
(carries sperm) is very long, complexly twisted, and rolled up in the form of a bundle. The spermatheca
(for storing sperm) is globular, with a short stem, but is quite distant from the genital pore (where the whole elaborate system opens to the outside world). The spermatheca is distant from this opening because of the remarkable elongation of the atrium or vestibule (a common area which is usually just inside the genital pore, the atrium is an area where both the male and the female systems open). There is a long retractor muscle from the vesicle, and its stem is fixed internally to the back of the slug in the median line (midline of the body) near the caudal end (tail end) of the body. The vas deferens and the spermatheca open nearly together into the far extremity of the atrium, which is prolonged in an attenuate form (drawn out in length) to an enormous extent. The very thin free oviduct (egg-carrying duct) opens into the atrium much nearer the near end, where the muscular vestibule is greatly but irregularly enlarged, and connected to the oviduct by a number of muscular fibres.
Within the vagina (the female organ which receives the copulatory organ during copulation) there is a curious series of flattened folds, the central part has a pointed end which is situated close to the genital pore, and this pointed end may possibly be a sarcobelum (a very much reduced version of an organ that makes love dart
s) and thus may be the homologue
(a similar structure because of shared ancestry) of the love dart
in the Helicidae
.
The radula
, which is inside the mouth of the slug, is a small but strong ribbon-like structure with numerous complex rows of tiny teeth. A radula is found only in molluscs.
In this species of slug the radula is 8 mm (5/16 in) long and 2 mm (1/16 in) wide, and has 240 slightly curved transverse (crosswise) rows of denticles (tiny teeth). Each row of teeth is composed of one median tooth and 10 lateral and marginal teeth on each side. The median teeth are small, and are clearly unicuspid (having one cusp), though they are slightly shouldered. The lateral teeth are bicuspid (having two cusps) but the admedian (next to the middle) teeth are noticeably larger than the median row, and the mesocone (an extra protrusion in the middle of the tooth) is well developed. There is however, no distinction between the lateral and marginal series except that the ectocone (extra little side protrusion) present on the admedian teeth recedes in position and slightly diminishes in size in the succeeding teeth up to about the twentieth row on the radula, but in the marginal series, the ectocone gradually grows in size and importance as the margin is approached, while the mesocone becomes almost correspondingly diminished, the outermost teeth showing a more embryonic (more like that of an embryo) character.
The jaw
measures about 1 mm (1/32 in) from side to side, and is distinctly arcuate (arched) from front to rear, lunate (crescent-moon shaped) in shape, but very wide, with broad and slightly rounded ends. The jaw is solid, dark-brown and has about 10 broad flat ribs only in the middle part of the jaw. These ribs are absent or scarcely discernible on the side areas. Where the ribs meet the upper edge they sometimes form crenulations ( a scalloped effect) and may also produce the same effect on the lower edge of the jaw. In other individuals the ribs extend all the way across the jaw, making both the upper and the cutting edges of the jaw clearly denticulate (noticeably toothed in outline).
The alimentary canal of the digestive system
forms two loops, as is true of all species within the family Arionidae.
(in other words, it occurs in discontinuous locations). It is found only in southwestern Ireland, north-west Spain, and from central Portugal to northern Portugal. There is evidence that the species evolved in the Iberian peninsula. The presence of this slug in southwest Ireland seems anomalous, but a similar occurrence has been observed in a few other species of animals and plants; this type of disjunct distribution (in Iberia and in Ireland without any intermediate localities) is known as "Lusitanian".
geology areas in West Cork
and County Kerry
, a total area of around 5800 km² (2,239.4 sq mi). The Kerry slug is listed as a "selection feature" for seven Special Areas of Conservation
(SACs) in Ireland, which together form a significant proportion of its range in that country. The seven SACs are Glengarriff Harbour and Woodland
; Caha Mountains
; Sheep's Head
; Killarney National Park
, Macgillycuddy's Reeks
and Caragh River Catchment
; Lough Yganavan and Lough Nambrackdarrig
; Cloonee and Inchiquin Loughs, Uragh Wood; Blackwater River (Kerry). Another SAC, St. Gobnet's Wood
, is due to be expanded to protect an area of slug habitat. The slug has also been recorded at other SACs where it is not a selection feature, for example Derryclogher Bog in County Cork.
, and its English common name of "Kerry slug", Ireland is not at the centre of this slug species' distribution; instead the distribution of this species is centred in continental Iberia
. This slug has been known from northern Spain since 1868, and from northern Portugal since 1873. It was once reported as occurring in France, but this was never confirmed, and so that record is considered suspect.
, Douro Litoral
, Minho
, Trás-os-Montes e Alto Douro
and the Peneda-Gerês National Park
, a protected area.
as far east as Mount Ganekogorta
in the Basque Country
. The localities in question fall within the boundaries of various autonomous communities: Galicia, Asturias
, Cantabria
, Castile and León
(provinces of León
, Palencia
and Zamora
), and the Basque Country (provinces of Biscay
and Álava
). There have been unconfirmed findings of this slug reported from Navarra.
Natura 2000
sites for this species in Spain include 48 localities (listed below, grouped by region):
, and adults become active at night, especially on rainy or very humid nights. Ireland however is much further north, so the temperatures there are considerably cooler, there is more rain, and the air is often quite damp; in Ireland this slug is sometimes active in the daytime as long as the weather is humid and overcast.
The Kerry slug has a very unusual defensive behaviour. When attacked, most land slugs will simply retract the head and contract the body, but stay firmly attached to the substrate
. In contrast, when this slug is threatened, it retracts its head, lets go of the substrate, rolls up completely, and stays contracted in a ball-like shape. This is a unique feature among all the Arionidae, and among all slugs in Ireland.
In Ireland this slug inhabits wild woodland
with oak
trees, and oligotrophic open moorland
s, as long as there are boulders covered with lichens and mosses in these habitats. In Spain it usually occurs in granite
mountains.
The Kerry slug usually prefers acidic soil and high humidity environments, living on moss
and lichen
-covered rocks and trees (mainly the chestnut Castanea sativa and some species of oak
), under fallen wood and under bark of rotten wood. It may also occur in open areas, such as hydrophilic pastures near oligotrophic water bodies.
s, moss
es, fungi (Fistulina hepatica) and bacteria
that grow on boulders and on tree trunks.
In captivity
, this species has been fed on porridge
, bread
, dandelion leaves, lichen Cladonia fimbriata
and various vegetable
s: (carrot
, cabbage
, cucumber
, lettuce
). It can be also carnivorous in captivity, and has been documented as devouring the snail Vitrina pellucida
.
s. Eggs
are laid in July to October in the wild, and from February to October in captivity. Self-fertilisation is also possible in this species. The eggs are laid in clusters of 18 to 30, and held together by a film of mucus
. The egg masses are about 3.5 x 2 cm in overall size.
The eggs are very large compared with the size of the animal, but vary within certain limits. The largest eggs are more elongate, being 8.5 × 4.25 mm; the smallest eggs are more regularly oval, and are only 6 × 3 mm. All are semitranslucent milky-white or opalescent when fresh, although some of the larger and more elongate ones show a somewhat transparent area at the smaller end. The opalescent lustre becomes lost in a few days, and the eggs turn yellowish, and later brown, or black.
The young appear to hatch in from 6 to 8 weeks, at which period the spots on the body of the animal are barely present, but the lateral bands are distinct and black, much more conspicuous than they are in mature slugs of this species. In juveniles the shield shows lyre
-shaped markings, as is the case in slugs of the genus Arion. However these lyre-shaped markings become indistinct as the slugs grow larger. The slugs probably pass the winter in the immature
stage. The body of preserved
juvenile specimens is up to 3 cm (1.2 in) long with a mantle
length of 10 mm.
Juveniles reach maturity in 2 years, at a length about 2.6 cm.
The life span of Geomalacus maculosus in the wild is up to seven years, but the lifespan in captivity is rarely over three years.
In numerous different localities in Spain, it was consistently the case that no more than a very few individuals of the species were observed.
, which reduces its lichen and moss food sources. This can lead to the local disappearance of the species, which was documented in Spain. Other threats include: intensification of land use (land reclamation
, using of pesticide
s, overgrazing by sheep, removing of shrub
s, building gardens, burning, and building roads and highways), tourism
, general development pressure, coniferous forest plantations, the spread of invasive species
of plants such as Rhododendron ponticum
and habitat fragmentation
(see also Moorkens 2006).
Other potential dangers to the species include climate change
and air pollution
, because these negatively affect the lichens which are a food source for the slug. Climate change will probably affect the Iberian populations more seriously, because the climate there is already on the hot and dry side relative to Ireland, which is generally rather cool and damp.
(Bern Convention), EIS Bern Invertebrates Project. This decision was backed by studies of its distribution and ecology
in Ireland which concluded that evidence of a decline in Iberia plus uncertainty over its status in Ireland supported its inclusion in the Convention.
Since 2006, Geomalacus maculosus has been considered as least concern
species in the IUCN Red List
, however during 1994 to 2006 it was considered to be vulnerable
.
Geomalacus maculosus is also protected by the European Union's Habitats Directive (which was a response to the Bern Convention) and has been listed as an Annex II and Annex IV species since 1992. There are two principal mechanisms used by the Directive to protect habitats and species – the creation of Special Areas of Conservation (SACs) and the protection of species independently of their habitats by other means. It is probably in areas not specifically protected as SACs that threats to the Kerry slug will be greatest.
Seven SACs have been designated for this species in Ireland and 49 SCIs in Spain.
The Habitats Directive protects the Kerry slug outside the SACs by Article 12 (1), which obliges EU member states:
Its conservation status in Spain for the IUCN criteria is vulnerable
.
, West Cork
; Uragh Wood Nature Reserve
, South Kerry; and Killarney National Park
, North Kerry. They concluded that the species could not be adequately safeguarded with only three sites, and therefore they supported its inclusion in the Bern list, to which the Irish government is a signatory.
The Habitats Directive was transposed
into Irish law
by:
The Irish National Parks and Wildlife Service
published a Species Action Plan for the Kerry slug in January 2008. This Action Plan was superseded in May 2010 by a Threat Response Plan, which addressed issues arising from a legal challenge to Ireland's transposition and implementation of the Habitats Directive.
covering 1988–2007, the conservation status of the species in Ireland was declared "favourable (FV)" in all evaluated criteria (range, population, habitat and future prospects).However, in 2007 the European Court of Justice
took the view that Ireland was not monitoring the species properly.
This point was conceded by the Threat Response Plan of 2010, which noted that population statistics were still deficient, particularly outside the SACs, and examined how monitoring of the species might be improved. As the Threat Response Plan noted, species monitoring is a process in which distribution and status of the subject are evaluated systematically over time. Under this definition no monitoring of the Kerry Slug had yet been undertaken in Ireland as at May 2010.
The Kerry Slug Survey of Ireland, a collaboration between the National Parks and Wildlife Service and the Applied Ecology Unit at the National University of Ireland, Galway
, was working in 2010 on a "suitable monitoring protocol", which was due to be published by 2011.
programme in terraria at its "Endangered Species Breeding Unit". The project is located not within the species' normal range, but in England at the Martin Mere Wetland Centre
. During the 1990s, slugs from the breeding programme were given out to a number of different zoos and individuals in order to set up their own breeding programmes, but unfortunately only a very few of those breeding groups survived.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of medium-sized to large air-breathing land slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...
. It is a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
pulmonate gastropod mollusc in the family Arionidae
Arionidae
Arionidae, common name the "roundback slugs" or "round back slugs" are a taxonomic family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the superfamily Arionoidea.- Distribution :...
, the roundback slugs.
An adult Kerry slug generally measures 7–8 cm (2.8–3.2 in) in length and is dark grey or brownish in colour, with yellowish spots. The internal anatomy of the slug shows some unusual features, and some characteristic differences from the genus Arion, which is the type genus of the family Arionidae. The Kerry slug was described in 1843, rather late compared to many other relatively large land gastropods that form a part of the fauna of the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
; this is one indication of this slug's rarity and its secretive habits.
Although the distribution of this slug species does include some wild habitats in southwestern Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
(e.g. in County Kerry
County Kerry
Kerry means the "people of Ciar" which was the name of the pre-Gaelic tribe who lived in part of the present county. The legendary founder of the tribe was Ciar, son of Fergus mac Róich. In Old Irish "Ciar" meant black or dark brown, and the word continues in use in modern Irish as an adjective...
), the species is more widespread in north-west Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and from central to northern Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
. However, it is not found anywhere between Ireland and Spain. The species appears to require environments that have high humidity and acidic soil (soil with no calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
in it). The slug is mostly nocturnal or crepuscular
Crepuscular
Crepuscular animals are those that are active primarily during twilight, that is during dawn and dusk. The word is derived from the Latin word crepusculum, meaning "twilight." Crepuscular is, thus, in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be active on a bright...
, although in Ireland it is active on overcast
Overcast
Overcast or overcast weather, as defined by the World Meteorological Organization, is the meteorological condition of clouds obscuring all of the sky. Overcast, written as "OVC" in the METAR observation, is reported when the cloud cover is observed to equal eight oktas .Sometimes clouds can be...
days. It feeds on lichens, liverwort
Marchantiophyta
The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....
s, moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es and fungi, which grow either on boulders or on tree trunks.
This rare species is officially protected by conservation
Conservation biology
Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction...
laws in each of the three countries in which it occurs. However, the survival of the Kerry slug is nonetheless threatened because it lives only in completely wild, unspoiled habitat of a particular type: acidic woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
s and moorland
Moorland
Moorland or moor is a type of habitat, in the temperate grasslands, savannas, and shrublands biome, found in upland areas, characterised by low-growing vegetation on acidic soils and heavy fog...
s that support the species of lower plants on which the slug relies for food. This habitat type is itself at risk from a number of different factors, ranging from climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
to the construction of roads. Attempts have been made to establish breeding populations in captivity
Captive breeding
Captive breedingis the process of breeding animals in human controlled environments with restricted settings, such as wildlife reserves, zoos and other conservation facilities; sometimes the process is construed to include release of individual organisms to the wild, when there is sufficient...
, to help ensure the survival of this slug species, but with only limited success.
Taxonomy
The Kerry slug is a gastropod, as are all other snailSnail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s and slugs, including slugs and snails that live in saltwater, those that live in freshwater, and those that live on the land. This is a land slug which breathes air, a pulmonate. It is in the clade Stylommatophora
Stylommatophora
Stylommatophora is a taxon of air-breathing land snails and slugs, terrestrial pulmonate gastropod molluscs. This taxon is currently considered to be a clade. It was previously regarded as an infraorder...
, which means that its primitive eyes or eye spots are carried on the tips of its two upper tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...
s. Despite superficial similarities, not all land slugs are in the same family or superfamily. The Kerry slug is an arionid, or round-backed slug; it has no keel
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
on its back, in contrast to the land slugs in the family Limacidae
Limacidae
Limacidae, common name the keelback slugs, are a taxonomic family of medium-sized to very large, air-breathing land slugs, terrestrial pulmonate gastropod molluscs in the superfamily Limacoidea.- Distribution :...
and Agriolimacidae
Agriolimacidae
Agriolimacidae is a family of small and medium sized land slugs, or shell-less snails, terrestrial pulmonate gastropod mollusks.- Distribution :Distribution of Limacidae is Holarctic, this include: Nearctic, western Palearctic and eastern Palearctic....
. It also shares numerous internal anatomical features with slug species in other genera within the family Arionidae
Arionidae
Arionidae, common name the "roundback slugs" or "round back slugs" are a taxonomic family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the superfamily Arionoidea.- Distribution :...
, including the Arion slugs, which are most typical of the family.
The Kerry slug's scientific name or binomial name is Geomalacus maculosus. It is in the genus Geomalacus, a name which literally means "earth mollusc". Its specific name maculosus means "spotted", from the Latin word macula "spot". The English language vernacular
Vernacular
A vernacular is the native language or native dialect of a specific population, as opposed to a language of wider communication that is not native to the population, such as a national language or lingua franca.- Etymology :The term is not a recent one...
name (or common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
) is derived from the name of County Kerry, which is the county in the southwest of Ireland where this species was first collected, and the type locality which is mentioned in the original description.
The scientific name of the species is also sometimes written as Geomalacus (Geomalacus) maculosus. This is because the genus Geomalacus contains two subgenera: the nominate subgenus (subgenus of the same name) Geomalacus and a second subgenus Arrudia Pollonera, 1890. The subgenus Geomalacus contains only one species, the Kerry slug. The subgenus Arrudia includes three species.
This slug species was originally described and named from specimens collected in Ireland. In 1842, an Irish naturalist named William Andrews (1802–1880) sent material that he had found at Caragh Lake
Caragh Lake
Caragh Lake is a large and scenic lake in County Kerry, Ireland.-Ecology:The lake is included within a large Special Area of Conservation, ....
in County Kerry
County Kerry
Kerry means the "people of Ciar" which was the name of the pre-Gaelic tribe who lived in part of the present county. The legendary founder of the tribe was Ciar, son of Fergus mac Róich. In Old Irish "Ciar" meant black or dark brown, and the word continues in use in modern Irish as an adjective...
to the Irish naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
George James Allman
George James Allman
George James Allman FRS , M.D., Emeritus Professor of Natural History in Edinburgh, was an eminent Irish naturalist.-Life:...
, who then introduced the slug to science as a new species.
Kerry slug has been included in molecular phylogenetic studies since 2001.
Description
The body length of adult slugs of this species is 7–8 cm (2.8–3.2 in). However it is difficult to measure these slugs accurately because of their unusual startle responseStartle reaction
The startle response is a brainstem reflex that serves to protect the back of the neck , or the eye , and also facilitates escape from sudden stimuli. It is found across the lifespan and in many species. An individual's emotional state may lead to a variety of different responses...
(see the section entitled behaviour). Kerry slugs can also elongate themselves within crevices up to 12 cm (4.8 in). "Official" measurements of this species vary, for example, Kerney et al. (1983) give slightly different measurements for the species: 6–9 cm (2.4–3.6 in). The body of a fixed (preserved) adult specimen was 7 cm (2.8 in) long with a mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
length of 3 cm (1.2 in).
The body of these slugs is glossy, and is covered on the left and right sides with about 25 longitudinal rows of polygonal granulations (very small knobs with outlines like polygons). These slugs are usually blackish or dark-grey in colour, sometimes with indistinct darker bands. On each side of the body there can be two bands: one band just below the summit of the back, and the other band further down the side of the body. When these bands are present they usually extend the whole length of the body of the slug, and are overspread by numerous, somewhat oval, yellowish spots. These yellow spots are distributed more or less in five longitudinal zones.
Behind the animal's head, the "shield" (the shield-shaped outer surface of the mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
) is about a third of the length of the body when the slug is actively crawling and thus extended, but only about half of that when the slug is motionless and contracted. The shield is rounded in front and bluntly pointed behind. The texture of the surface of this area resembles the underside of untanned leather. It is spotted with pale buff or whitish spots similar to those on the body, but more uniformly distributed.
The foot-fringe (a band of tissue around the edge of the foot) is not very distinctly separated: it is very pale and somewhat expanded, with indistinct lines on it. The sole of the foot is pale grayish yellow in colour, and is divided into three indistinct bands, with the mid-area being somewhat darker and more transparent than the sides. There is a caudal mucous pit
Caudal mucous pit
The caudal mucous pit, or caudal mucous horn, is an anatomical structure on the tail end of the foot of various land snails and slugs, terrestrial pulmonate gastropod mollusks....
situated between the foot and the body on the upper surface of the tip of the tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
. The pit (which collects extra mucus) is not very conspicuous, but it is triangular in shape and opens transversely (i.e. from side to side). The mucous pit often carries a transparent yellowish ball of slime (mucus).
The upper tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...
s are smoky-black or grey, short and thick, with oval ends, and have the usual eye spots at their tips. The genital pore (or opening) lies behind and below the right eye-tentacle. The lower tentacles are pale translucent grey. The skin mucus is usually pale yellow, and varies in its degree of viscosity (stickiness). The locomotory-mucus (mucus for crawling on) is tenacious and usually colourless, but it can be yellowish because of having mixed with the body slime.
Shell
Most land slugs have, within the mantle, the remnants of what was once (in the evolutionary past), a larger external shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
, and this exists either in the form of an internal shell (a thin shelly plate), or a collection of shelly granules. In this species there is an internal shell or shell plate which resembles that found in land slugs of the genus Limax
Limax
Limax is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Limacidae.The generic name Limax literally means "slug"....
. In other words, the shell plate in this species is oval in shape, solid and calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
(chalky), with a transparent conchiolin
Conchiolin
Conchiolin and perlucin are complex proteins which are secreted by a mollusc's outer epithelium ....
(horny) base. It is usually somewhat convex above and concave beneath, with a few indistinct concentric lines of growth, and is covered outwardly with a very thin transparent periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
(a protein layer), and with the nucleus (the oldest growth part) near the front. In young animals, the shell is very thin and convex, abruptly cut off behind, but with an extremely thin layer that projects in front and contains minute granules.
The drawing of the shell can slightly differ in various authors showing, that it is just a solid plate:
Various organ systems
The circulatoryCirculatory system of gastropods
As in other molluscs, the circulatory system of gastropods is open, with the fluid, or haemolymph, flowing through sinuses and bathing the tissues directly. The haemolymph typically contains haemocyanin, and is blue in colour.-Circulation:...
and excretory system
Excretory system of gastropods
The excretory system of gastropods removes nitrogenous waste and maintains the internal water balance of these creatures, commonly referred to as snails and slugs...
are closely related, in that the heart is surrounded by the triangular kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
. The kidney has a lamellate (layered) structure and it has two ureter
Ureter
In human anatomy, the ureters are muscular tubes that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long and ~3-4 mm in diameter....
s. In this slug species, the ventricle
Ventricle
Ventricle may refer to:* Ventricle , the pumping chambers of the heart* Ventricular system in the brain* Ventricle of the larynx, a structure in the larynx* Stomach of the gastrointestinal tract...
of the heart is directed towards, and is very close to, the anal
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
and respiratory openings. The ventricle of the heart is further away and further back than it is in species of the related genus Arion
Arion (genus)
Arion is a genus of air-breathing land slugs, specifically roundback slugs, called "roundback" because they have no keel on the back of the body.The genus name Arion is taken from that of the legendary ancient Greek poet Arion.-Species:...
, the type genus of the family Arionidae.
The gland above the foot, the suprapedal gland
Suprapedal gland
The suprapedal gland or mucous pedal gland is an anatomical feature found in some snails and slugs. It is a gland located inside the front end of the foot of gastropods.The term suprapedal means "above the foot"....
, is deeply imbedded in the tissues, and reaches far back. The cephalic (head) gland known as the Semper's organ
Semper's organ
The Semper's organ is an anatomical structure of molluscs, a gland located in the head of some pulmonate gastropods.This organ was named after the German zoologist Carl Gottfried Semper, who first published information about this anatomical structure in 1856....
is well developed, and shows as a pair of strong flattened lobes. The salivary
Salivary gland
The salivary glands in mammals are exocrine glands, glands with ducts, that produce saliva. They also secrete amylase, an enzyme that breaks down starch into maltose...
and digestive glands are the same as those found in Arion species, but the vestigial osphradium
Osphradium
The osphradium is the olfactory organ in certain molluscs, linked with the respiration organ.The main function of this is to test incoming water for silt and other possible food particles.It is used by all members of the Genus Conus....
(kidney-like structure) within the mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
chamber is more distinct than it is in Arion species.
Muscles
As for the various muscles of the slug, the cephalic retractors (muscles for pulling in the head) are very much the same as they are in Arion species. The right and left tentacular muscles, which pull in all four of the tentacles, divide early for the upper and lower tentacles, but only the muscles of the ommatophores (the muscles of the two upper tentacles, which have eye spots) are darkly pigmented. The right and left muscles that pull in the eyespot tentacles are attached at the base to the back edge of the mantle, on the right and left respectively. The pharyngeal (throat) retractor muscle is, as usual, furcate (split) for attachment to the back of the buccal bulb (mouth bulb), and the root of this muscle is fixed on the right side of the body, just behind where the right tentacular muscle is attached.Reproductive system
Kerry slug is hermaphroditeHermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
as all other pulmonates. Its reproductive system
Reproductive system of gastropods
The reproductive system of gastropods varies greatly from one group to another within this very large and diverse taxonomic class of animals...
is diagnostic feature. Genus Geomalacus
Geomalacus
Geomalacus is a genus of large air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Arionidae, the roundback slugs.- Etymology :The Ancient Greek word geo means the Earth...
has a special feature: the atrium has diverticulum. This atrial diverticulum is elongated part of the atrium. Penis in the genus Geomalacus is reduced and lost as well its penial retractor muscle. Atrial diverticulum is secondary penial structure and with its spermatheca retractor muscle atrium acts as a copulatory organ instead. The second end of the spermatheca retractor muscle extends into posterior end of the body. Atrial diverticulum is morphological equivalent (analogy
Analogy
Analogy is a cognitive process of transferring information or meaning from a particular subject to another particular subject , and a linguistic expression corresponding to such a process...
, homoplasy) of penis.
Geomalacus maculosus has atrial diverticulum longer than spermatheca duct, while Geomalacus anguiformis
Geomalacus anguiformis
Geomalacus anguiformis is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusc in the family Arionidae, the round back slugs.- Distribution:This species occurs in south Portugal and central Spain....
has atrial diverticulum shorter than spermatheca duct.
Various authors have depicted the reproductive system of Kerry slug: Godwin-Austen
Henry Haversham Godwin-Austen
Lieutenant-Colonel Henry Haversham Godwin-Austen FRS FZS FRGS MBOU , was an English topographer, geologist and surveyor.The eldest son of Robert Alfred Cloyne Godwin-Austen, Godwin-Austen was born in Teignmouth...
(1882), Sharff (1891), Simroth (1891, 1894), Taylor (1907), Germain (1930), Quick (1960) and Platts & Speight (1988). Platts & Speight (1988) consider from previous authors depiction by Godwin-Austen (1882) to be the most accurate, because other authors depicted atrium too short.
The Kerry slug's reproductive organs are as follows: there is a small, compact, and darkly pigmented ovotestis
Ovotestis
An ovotestis is a gonad with both testicular and ovarian aspects. In humans, ovotestes are an anatomical abnormality associated with gonadal dysgenesis.- In gastropods :...
(a combination of ovary and testis). There is a hermaphroditic duct (male and female duct) which is very long and greatly convoluted, and ends in a small spherical vesicula seminalis (seminal vesicle). The albumen gland (which creates albumen for the eggs) is elongated and shaped like a tongue. The ovispermatoduct (a duct that carries both eggs and sperm) is very much twisted. The free oviduct (duct that carries eggs only) is rather long and thin, but without any enlargement.
The vas deferens
Vas deferens
The vas deferens , also called ductus deferens, , is part of the male anatomy of many vertebrates; they transport sperm from the epididymis in anticipation of ejaculation....
(carries sperm) is very long, complexly twisted, and rolled up in the form of a bundle. The spermatheca
Spermatheca
The spermatheca , also called receptaculum seminis , is an organ of the female reproductive tract in insects, some molluscs, oligochaeta worms and certain other invertebrates and vertebrates...
(for storing sperm) is globular, with a short stem, but is quite distant from the genital pore (where the whole elaborate system opens to the outside world). The spermatheca is distant from this opening because of the remarkable elongation of the atrium or vestibule (a common area which is usually just inside the genital pore, the atrium is an area where both the male and the female systems open). There is a long retractor muscle from the vesicle, and its stem is fixed internally to the back of the slug in the median line (midline of the body) near the caudal end (tail end) of the body. The vas deferens and the spermatheca open nearly together into the far extremity of the atrium, which is prolonged in an attenuate form (drawn out in length) to an enormous extent. The very thin free oviduct (egg-carrying duct) opens into the atrium much nearer the near end, where the muscular vestibule is greatly but irregularly enlarged, and connected to the oviduct by a number of muscular fibres.
Within the vagina (the female organ which receives the copulatory organ during copulation) there is a curious series of flattened folds, the central part has a pointed end which is situated close to the genital pore, and this pointed end may possibly be a sarcobelum (a very much reduced version of an organ that makes love dart
Love dart
A love dart is a hard, long, sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs create. Love darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship, before actual mating takes place...
s) and thus may be the homologue
Homology (biology)
Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...
(a similar structure because of shared ancestry) of the love dart
Love dart
A love dart is a hard, long, sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs create. Love darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship, before actual mating takes place...
in the Helicidae
Helicidae
The Helicidae, sometimes known as the typical snails, are a taxonomic family of small to large, air-breathing, land snails. In other words, they are terrestrial pulmonate gastropod mollusks....
.
Radula
The radula
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
, which is inside the mouth of the slug, is a small but strong ribbon-like structure with numerous complex rows of tiny teeth. A radula is found only in molluscs.
In this species of slug the radula is 8 mm (5/16 in) long and 2 mm (1/16 in) wide, and has 240 slightly curved transverse (crosswise) rows of denticles (tiny teeth). Each row of teeth is composed of one median tooth and 10 lateral and marginal teeth on each side. The median teeth are small, and are clearly unicuspid (having one cusp), though they are slightly shouldered. The lateral teeth are bicuspid (having two cusps) but the admedian (next to the middle) teeth are noticeably larger than the median row, and the mesocone (an extra protrusion in the middle of the tooth) is well developed. There is however, no distinction between the lateral and marginal series except that the ectocone (extra little side protrusion) present on the admedian teeth recedes in position and slightly diminishes in size in the succeeding teeth up to about the twentieth row on the radula, but in the marginal series, the ectocone gradually grows in size and importance as the margin is approached, while the mesocone becomes almost correspondingly diminished, the outermost teeth showing a more embryonic (more like that of an embryo) character.
Jaw
The jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
measures about 1 mm (1/32 in) from side to side, and is distinctly arcuate (arched) from front to rear, lunate (crescent-moon shaped) in shape, but very wide, with broad and slightly rounded ends. The jaw is solid, dark-brown and has about 10 broad flat ribs only in the middle part of the jaw. These ribs are absent or scarcely discernible on the side areas. Where the ribs meet the upper edge they sometimes form crenulations ( a scalloped effect) and may also produce the same effect on the lower edge of the jaw. In other individuals the ribs extend all the way across the jaw, making both the upper and the cutting edges of the jaw clearly denticulate (noticeably toothed in outline).
The alimentary canal of the digestive system
Digestive system of gastropods
The digestive system of gastropods has evolved to suit almost every kind of diet and feeding behavior. Gastropods as the largest taxonomic class of the mollusca are very diverse indeed: the group includes carnivores, herbivores, scavengers, filter feeders, and even parasites.In particular, the...
forms two loops, as is true of all species within the family Arionidae.
Distribution
Geomalacus maculosus has what is known as a disjunct distributionDisjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
(in other words, it occurs in discontinuous locations). It is found only in southwestern Ireland, north-west Spain, and from central Portugal to northern Portugal. There is evidence that the species evolved in the Iberian peninsula. The presence of this slug in southwest Ireland seems anomalous, but a similar occurrence has been observed in a few other species of animals and plants; this type of disjunct distribution (in Iberia and in Ireland without any intermediate localities) is known as "Lusitanian".
Ireland
Within Ireland, this species of slug is known from sandstoneSandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
geology areas in West Cork
West Cork
West Cork refers to a geographical area in south-west Ireland, lying within Ireland's largest county, County Cork. Traditionally a popular tourist destination, the area is seen as being distinct from the more populated northern or eastern parts of the county, as well as the more urban area of...
and County Kerry
County Kerry
Kerry means the "people of Ciar" which was the name of the pre-Gaelic tribe who lived in part of the present county. The legendary founder of the tribe was Ciar, son of Fergus mac Róich. In Old Irish "Ciar" meant black or dark brown, and the word continues in use in modern Irish as an adjective...
, a total area of around 5800 km² (2,239.4 sq mi). The Kerry slug is listed as a "selection feature" for seven Special Areas of Conservation
Special Area of Conservation
A Special Area of Conservation is defined in the European Union's Habitats Directive , also known as the Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora...
(SACs) in Ireland, which together form a significant proportion of its range in that country. The seven SACs are Glengarriff Harbour and Woodland
Glengarriff
Glengarriff is a village of approximately 800 people on the N71 national secondary road in the south-west region of County Cork, Ireland. Known internationally as a tourism venue, it boasts many natural attractions...
; Caha Mountains
Caha Mountains
The Caha Mountains are a range of low sandstone mountains situated on the Beara peninsula in south-west County Cork, in the Ireland. The highest peak is Hungry Hill, 685m tall.-See also:*List of mountains in Ireland...
; Sheep's Head
Sheep's Head
Sheep's Head, also known as Muntervary , is the headland at the end of the peninsula between Bantry Bay and Dunmanus Bay in County Cork, Ireland....
; Killarney National Park
Killarney National Park
Killarney National Park is located beside the town of Killarney, County Kerry, Ireland. It was the first national park established in Ireland, created when Muckross Estate was donated to the Irish state in 1932...
, Macgillycuddy's Reeks
Macgillycuddy's Reeks
MacGillycuddy's Reeks is a mountain range in County Kerry, Republic of Ireland. Stretching slightly over , it includes the highest peaks in Ireland and the only peaks on the island that are over . The highest of these is Corrán Tuathail or Carrauntoohil , followed by Binn Chaorach and Cathair na...
and Caragh River Catchment
Caragh River Catchment
The River Caragh is a river in County Kerry in southwestern Ireland.The river is relatively unpolluted and its catchment area of about comes under the protection of a Special Area of Conservation .This is one area in which the rare Kerry Slug is known to occur.-References:* Fishing:* , National...
; Lough Yganavan and Lough Nambrackdarrig
Lough Yganavan and Lough Nambrackdarrig
Lough Yganavan and Lough Nambrackdarrig are two lakes of ecological importance in County Kerry, in southwestern Ireland. They are included in a Special Area of Conservation of 271.57 ha, which protects land in private ownership and state-owned nature reserve...
; Cloonee and Inchiquin Loughs, Uragh Wood; Blackwater River (Kerry). Another SAC, St. Gobnet's Wood
St. Gobnet's Wood
St Gobnet's Wood is an area of oak woodland at Baile Bhuirne, County Cork, south-western Ireland. The wood, according to the National Parks and Wildlife Service's survey, is about 30 ha in extent....
, is due to be expanded to protect an area of slug habitat. The slug has also been recorded at other SACs where it is not a selection feature, for example Derryclogher Bog in County Cork.
Iberia: Spain and Portugal
Despite its first "discovery" at Caragh LakeCaragh Lake
Caragh Lake is a large and scenic lake in County Kerry, Ireland.-Ecology:The lake is included within a large Special Area of Conservation, ....
, and its English common name of "Kerry slug", Ireland is not at the centre of this slug species' distribution; instead the distribution of this species is centred in continental Iberia
Iberian Peninsula
The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...
. This slug has been known from northern Spain since 1868, and from northern Portugal since 1873. It was once reported as occurring in France, but this was never confirmed, and so that record is considered suspect.
Portugal
The southernmost locality where this species is found is the mountain range Serra da Estrela in Portugal. Other Portuguese localities include the provinces Beira AltaBeira Alta
Beira Alta Province was a Portuguese province in the north of Portugal.Vast plateaus, river valleys, mountains, and castles abound in Beira Alta.Formerly it was part of the Beira Province.The two main cities were Guarda and Viseu...
, Douro Litoral
Douro Litoral
Douro Litoral is a historical province of Portugal. It is centered on the city of Porto, now the capital of the Norte Region. Other important cities in the province are Vila Nova de Gaia, Matosinhos, Maia, Póvoa de Varzim, and the historically important Penafiel, Amarante, Feira, Vila do Conde.The...
, Minho
Minho (province)
Minho is an historical province of Portugal. It was established as an official province in 1936 and dissolved in 1976. It consisted of 23 municipalities, with its capital in the city of Braga. Today, the area would include the districts of Braga and Viana do Castelo. Minho has substantial Celtic...
, Trás-os-Montes e Alto Douro
Trás-os-Montes e Alto Douro
Trás-os-Montes e Alto Douro is a historical province of Portugal located in the northeastern corner of the country. Vast plateaus, river valleys, mountains, and castles abound in Trás os Montes e Alto Douro....
and the Peneda-Gerês National Park
Peneda-Gerês National Park
The Peneda-Gerês National Park , also known simply as Gerês, is the only national park in Portugal...
, a protected area.
Spain
The distribution of this species in Spain includes coastal locations in Galicia, and extends through the Cantabrian MountainsCantabrian Mountains
The Cantabrian Mountains or Cantabrian Range are one of the main systems of mountain ranges in Spain.They extend for more than approximately 180 miles across northern Spain, from the western limit of the Pyrenees to the edges of the Galician Massif close to Galicia, along the coast of the...
as far east as Mount Ganekogorta
Ganekogorta
Ganekogorta is a mountain in the border of the provinces of Biscay and Alava , just between Bilbao and Llodio. It has a height of 998 m AMSL and it's the main peak of a massif that comprises some smaller mountains like Pagasarri, Ganeta, Pasatorenkorta, Arnotegi or Arraiz...
in the Basque Country
Basque Country (autonomous community)
The Basque Country is an autonomous community of northern Spain. It includes the Basque provinces of Álava, Biscay and Gipuzkoa, also called Historical Territories....
. The localities in question fall within the boundaries of various autonomous communities: Galicia, Asturias
Asturias
The Principality of Asturias is an autonomous community of the Kingdom of Spain, coextensive with the former Kingdom of Asturias in the Middle Ages...
, Cantabria
Cantabria
Cantabria is a Spanish historical region and autonomous community with Santander as its capital city. It is bordered on the east by the Basque Autonomous Community , on the south by Castile and León , on the west by the Principality of Asturias, and on the north by the Cantabrian Sea.Cantabria...
, Castile and León
Castile and León
Castile and León is an autonomous community in north-western Spain. It was so constituted in 1983 and it comprises the historical regions of León and Old Castile...
(provinces of León
León (province)
León is a province of northwestern Spain, in the northwestern part of the autonomous community of Castile and León.About one quarter of its population of 500,200 lives in the capital, León. The weather is cold and dry during the winter....
, Palencia
Palencia (province)
Palencia is a province of northern Spain, in the northern part of the autonomous community of Castile and León. It is bordered by the provinces of León, Cantabria, Burgos, and Valladolid....
and Zamora
Zamora (province)
Zamora is a Spanish province of western Spain, in the western part of the autonomous community of Castile and León.The present-day province of Zamora province was one of three provinces formed from the former Kingdom of León in 1833, when Spain was re-organised into 49 provinces.It is bordered by...
), and the Basque Country (provinces of Biscay
Biscay
Biscay is a province of Spain and a historical territory of the Basque Country, heir of the ancient Lord of Biscay. Its capital city is Bilbao...
and Álava
Álava
Álava is a province of Spain and a historical territory of the Basque Country, heir of the ancient Lord of Álava. Its capital city is Vitoria-Gasteiz which is also the capital of the autonomous community...
). There have been unconfirmed findings of this slug reported from Navarra.
Protected sites
Natura 2000
Natura 2000
Natura 2000 is an ecological network of protected areas in the territory of the European Union.-Origins:In May 1992, the governments of the European Communities adopted legislation designed to protect the most seriously threatened habitats and species across Europe. This legislation is called the...
sites for this species in Spain include 48 localities (listed below, grouped by region):
- Asturias
-
- MuniellosMuniellos nature reserveThe Muniellos nature reserve protects a wooded area in Asturias, Spain. The area of the nature reserve is 5,488 ha. The main species of tree is oak. In the 1970s timber extraction was forbidden and the woods were preserved as a hunting reserve...
; PongaPonga, AsturiasPonga is a town and municipality in the province and autonomous community of Asturias, northwestern Spain. Its capital is San Juan de Beleño.-Ecology:Ponga has a natural park.Also, "Ponga-Amieva" is the name of a Special Protection Area for wild birds....
—AmievaAmievaAmieva is a municipality in the autonomous community of Asturias, Spain. It is also the name of one of the municipality's subdivisions ....
; RedesRedes Natural ParkThe Redes Natural Park is located in the Principality of Asturias in northern Spain. Its total area is , split between two municipalities: Caso and Sobrescobio . It was declared a natural park in 1996.-Conservation:...
;- Cantabria
- Camesa riverCamesa (river)The Camesa is a river located in the north of Spain, a tributary of the Douro River.It rises in the province of Palencia in the municipio of Brañosera...
; LiebanaLiébanaLiébana is a comarca of Cantabria .It covers 570 square kilometers and is located in the southwest of Cantabria, bordering Asturias, León and Palencia...
(Special Area of Conservation; LiébanaLiébanaLiébana is a comarca of Cantabria .It covers 570 square kilometers and is located in the southwest of Cantabria, bordering Asturias, León and Palencia...
(Special Protection AreaSpecial Protection AreaA Special Protection Area or SPA is a designation under the European Union Directive on the Conservation of Wild Birds.Under the Directive, Member States of the European Union have a duty to safeguard the habitats of migratory birds and certain particularly threatened birds.Together with Special...
); "Upper valleys of the Nansa and SajaSaja and Nansa valleysThe Valleys of the Saja and Nansa Rivers comprise an administrative comarca in Cantabria, Spain. It is formed by the valleys of said rivers, each one being a natural comarca of its own.-Saja valley:...
and Alto CampooAlto CampooAlto Campoo is a ski resort in the Cantabrian Mountains of northern Spain. The resort is located in the Cantabrian comarca of Campoo.The source of the river Ebro is near the resort in the town of Fontibre.-The resort:...
");- Castile and León
- Hoces de VegacerveraVegacerveraVegacervera is a municipality located in the province of León, Castile and León, Spain. According to the 2004 census , the municipality has a population of 334 inhabitants....
; Lake SanabriaSanabria Lake Natural ParkThe Sanabria Lake Natural Park is a natural park located around Lake Sanabria in the Sanabria comarca, northwest part of the Zamora province, in the mountainous area of Sierra Segundera and Sierra de la Cabrera...
and its vicinities; Montes AquilanosMontes AquilanosMontes Aquilanos, also known as Montes de El Bierzo and Alpes Bergidenses, is a mountain range within Montes de León, located to the south-southeast of the region of El Bierzo, pertaining to the Province of León in the autonomous region of Castile and León, Spain.It serves as border between the...
(Site of Community ImportanceSite of Community ImportanceA Site of Community Importance is defined in the European Commission Habitats Directive as a site which, in the biogeographical region or regions to which it belongs, contributes significantly to the maintenance or restoration at a favourable conservation status of a natural habitat type or of a...
); Montes Aquilanos y Sierra de Teleno (Special Protection Area); - Natural Park of Fuentes Carrionas and Fuente Cobre-Montaña PalentinaNatural Park of Fuentes Carrionas and Fuente Cobre-Montaña PalentinaFuentes Carrionas y Fuente Cobre-Montaña Palentina is a natural park in Castile and León, Spain.The park was declared in 2000 and is one of a number of protected areas in the Cantabrian Mountains....
; Sierra de la CabreraSierra de la CabreraThe Sierra de la Cabrera is a mountain range in northern Spain. The landscape shows evidence of past glaciation.The Sierra de la Cabrera gives its name to a Site of Community Importance , and a Special Protection Area ....
- two sites of the same name, one a Site of Community Importance, and the other a Special Protection Area.- Galicia
- A Marronda; Anllóns river; Baixa LimiaA Baixa LimiaA Baixa Limia is a local region in the Galician Province of Ourense. The overall population of this local region is 9,245 .-Municipalities:Bande, Entrimo, Lobeira, Lobios and Muíños....
; Baixa Limia - Serra do XurésBaixa Limia - Serra do XurésBaixa Limia - Serra do Xurés is a natural park in Galicia, Spain. The park was designated in 1993. Serra do Xurés is the Galician name for a range of mountains which straddle the border between Spain and Portugal: the Portuguese variant is Gerês and the Castilian variant is Xures .-International...
; Baixo MiñoMinho RiverThe Minho or Miño is the longest river in Galicia, Spain, with an extension of 340 km.Both names come from Latin Minius...
; Bidueiral de MontederramoMontederramoMontederramo is a municipality in Ourense in the Galicia region of north-west Spain....
; Carballido, a woodland site in A FonsagradaA FonsagradaA Fonsagrada is a town and municipality in the province of Lugo in the autonomous community of Galicia in north-west Spain which is 25 miles east-north-east of Lugo by road. Its population in 2004 was 5,007. A Fonsagrada is situated 3166 feet above sea-level on the watershed between the rivers...
; CarnotaCarnotaCarnota is a municipality of Spain in the province of A Coruña, autonomous community of Galicia. It has an area of 66.4 km², a population of 5285 and a population density of 79.59 people/km² It is famous because of its majestic hórreo, granary, the largest one in the world. It has a barrocan...
- Monte Pindo; Cíes IslandsCíes IslandsThe Cíes Islands are an archipelago off the coast of Pontevedra in Galicia , in the mouth of the Ría de Vigo. They belong to the parish of San Francisco de Afora, in the municipality of Vigo...
; Costa ÁrtabraCosta ÁrtabraCosta Ártabra, or Golfo Ártabro, is a coastal area of Galicia . It is comprised between the costa da Morte and the Rías Altas; it has a maximum width of 5,800 meters, and a depth of 5,600 meters corresponding to the mouth of the Río Mero at Santa Cristina. Other rivers which have their mouth in the...
; Costa da MorteCosta da MorteCosta da Morte is part of the Spanish Galician coast. The Costa da Morte extends from the villages of Fisterra and Malpica.The Costa da Morte received its name because there have been so many shipwrecks along its treacherous rocky shore...
- two areas, Costa da Morte and Costa da Morte (Northern); Cruzul-Agüeira; Encoro de AbegondoAbegondoAbegondo is a municipality of Spain in the Province of A Coruña, in the autonomous community of Galicia. It has an area of 83.72 km² , a population of 5,732 and a population density of 68.47 people/km² ....
-CecebreCambreCambre is a municipality of Spain in the Province of A Coruña, in the autonomous community of Galicia. It is located 12 km from the capital city and ten minutes away from the city's airport, Alvedro....
; Eo river (included among the Galician sites although the estuary forms the boundary with Asturias); Costa de Ferrolterra-ValdoviñoValdoviñoValdoviño is a municipality in the province of A Coruña, in the autonomous community of Galicia, north-western Spain.- Geography :The granite coast of Valdoviño is home to several sandy beaches, a large lagoon and a lighthouse.- Parroquias :...
; Fragas do EumeFragas do EumeThe Fragas do Eume are a natural park situated in north-west Spain. Fraga is a Galician word for "natural woodland", and the park is an example of a temperate rainforest in which oak is the climax vegetation...
; Macizo Central, Ourense (province)Ourense (province)Ourense is a province of northwestern Spain, in the southeastern part of the Autonomous Community of Galicia. It is bordered by the provinces of Pontevedra in the west, Lugo in the north, León and Zamora in the east, and by Portugal in the south. With an area of 7,278 square km it is the only...
; Monte AloiaMonte AloiaMonte Aloia is a summit in the mountains of Galicia, Spain, which was declared a natural park on 4 December 1978. The park covers an area of 746 hectares and is located within the municipality of Tui, a town on the River Miño....
; Monte Maior; NegueiraNegueiraNegueira is one of seven parishes in the municipality of Grandas de Salime, within the province and autonomous community of Asturias, in northern Spain.The population is 35 .-Villages and hamlets:*Airela*Armilda...
; Pena TrevincaTrevincaPeña Trevinca , also known as Trevinca, is a mountain in northern Spain. It is located at the confluence of the Montes de León and the Macizo Galaico on the boundary between the autonomous communities of Galicia and Castile and León...
; Pena Veidosa; Serra do Candán; Serra do Cando; Serra do Xistral; Sil river canyon; Sobreirais do ArnegoRiver ArnegoThe River Arnego is a river in the province of Pontevedra, Galicia, Spain. It is a tributary of the Ulla....
; TambreTambre (river)The Tambre River is a coastal river that crosses Galicia, in northwestern Spain. Its basin comprehends a total area of 1.531 km².The river flows through the province of A Coruña; the municipalities along its course are Sobrado, Curtis, Vilasantar, Boimorto, Mesía, Frades, Arzúa, O Pino, Oroso,...
- two areas, the river and its estuary; Támega river; Ulla-Deza river system- More than one region
- Ancares - This distict is divided between Galicia and Castile and LeónCastile and LeónCastile and León is an autonomous community in north-western Spain. It was so constituted in 1983 and it comprises the historical regions of León and Old Castile...
. Sierra de los AncaresSerra dos AncaresThe Serra dos Ancares is a mountain range in north-west Spain, extending in a south-westerly direction from the western end of the Cantabrian Mountains in Asturias....
is a mountain range which forms the boundary between the two autonomous communities, and which gives its name to a Natura 2000 site in the province of León. On the Galician side of the sierra are two sites for the slug - Ancares and Ancares-Courel.
- Muniellos
-
- Picos de EuropaPicos de EuropaThe Picos de Europa is a range of mountains 20 km inland from the northern coast of Spain, located in the Autonomous Communities of Asturias, Cantabria and Castile and León, forming part of the Cantabrian Mountains...
- This mountain range is divided between three autonomous communities. The three sites listed (Picos de Europa, Picos de Europa (Asturias), Picos de Europa en Castilla y León) include protected areas in the Picos de Europa National ParkPicos de Europa National ParkThe Picos de Europa National Park is a National Park in the Picos de Europa mountain range, in northern Spain. It is shared by the autonomous communities of Asturias, Cantabria and Castile and León.-History:...
and a regional park in Castile and Leon which is also called Picos de Europa.
- Picos de Europa
Behaviour
This species of slug is primarily nocturnal, in other words it is usually only active at night. During the daylight hours, these slugs are usually hidden in crevices of rocks and under loose bark on trees. In Iberia, juvenile slugs of this species become active during twilightTwilight
Twilight is the time between dawn and sunrise or between sunset and dusk, during which sunlight scattering in the upper atmosphere illuminates the lower atmosphere, and the surface of the earth is neither completely lit nor completely dark. The sun itself is not directly visible because it is below...
, and adults become active at night, especially on rainy or very humid nights. Ireland however is much further north, so the temperatures there are considerably cooler, there is more rain, and the air is often quite damp; in Ireland this slug is sometimes active in the daytime as long as the weather is humid and overcast.
The Kerry slug has a very unusual defensive behaviour. When attacked, most land slugs will simply retract the head and contract the body, but stay firmly attached to the substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
. In contrast, when this slug is threatened, it retracts its head, lets go of the substrate, rolls up completely, and stays contracted in a ball-like shape. This is a unique feature among all the Arionidae, and among all slugs in Ireland.
Ecology
Habitat
Geomalacus maculosus lives only in wild habitats and thus it is never an agricultural pest, unlike some other slugs in the family Arionidae.In Ireland this slug inhabits wild woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
with oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
trees, and oligotrophic open moorland
Moorland
Moorland or moor is a type of habitat, in the temperate grasslands, savannas, and shrublands biome, found in upland areas, characterised by low-growing vegetation on acidic soils and heavy fog...
s, as long as there are boulders covered with lichens and mosses in these habitats. In Spain it usually occurs in granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
mountains.
The Kerry slug usually prefers acidic soil and high humidity environments, living on moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
and lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
-covered rocks and trees (mainly the chestnut Castanea sativa and some species of oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
), under fallen wood and under bark of rotten wood. It may also occur in open areas, such as hydrophilic pastures near oligotrophic water bodies.
Feeding
The food of Geomalacus maculosus includes lichens, liverwortMarchantiophyta
The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....
s, moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es, fungi (Fistulina hepatica) and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
that grow on boulders and on tree trunks.
In captivity
Captivity (animal)
Animals that live under human care are in captivity. Captivity can be used as a generalizing term to describe the keeping of either domesticated animals or wild animals. This may include for example farms, private homes and zoos...
, this species has been fed on porridge
Porridge
Porridge is a dish made by boiling oats or other cereal meals in water, milk, or both. It is usually served hot in a bowl or dish...
, bread
Bread
Bread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...
, dandelion leaves, lichen Cladonia fimbriata
Cladonia fimbriata
Cladonia fimbriata is a species of lichen belonging to the family Cladoniaceae....
and various vegetable
Vegetable
The noun vegetable usually means an edible plant or part of a plant other than a sweet fruit or seed. This typically means the leaf, stem, or root of a plant....
s: (carrot
Carrot
The carrot is a root vegetable, usually orange in colour, though purple, red, white, and yellow varieties exist. It has a crisp texture when fresh...
, cabbage
Cabbage
Cabbage is a popular cultivar of the species Brassica oleracea Linne of the Family Brassicaceae and is a leafy green vegetable...
, cucumber
Cucumber
The cucumber is a widely cultivated plant in the gourd family Cucurbitaceae, which includes squash, and in the same genus as the muskmelon. The plant is a creeping vine which bears cylindrical edible fruit when ripe. There are three main varieties of cucumber: "slicing", "pickling", and...
, lettuce
Lettuce
Lettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. It is eaten either raw, notably in salads, sandwiches, hamburgers, tacos, and many other dishes, or cooked, as in Chinese cuisine in which the stem becomes just as important...
). It can be also carnivorous in captivity, and has been documented as devouring the snail Vitrina pellucida
Vitrina pellucida
Vitrina pellucida is species of small land snail, a terrestrial pulmonate gastropod mollusk in the family Vitrinidae, the glass snails.- Distribution :...
.
Life cycle
The mating of this species is in head-to-head position with genital openings to each other. Atria are shaped as a funnel with fluted edges after mating. There are not known spermatophoreSpermatophore
A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...
s. Eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
are laid in July to October in the wild, and from February to October in captivity. Self-fertilisation is also possible in this species. The eggs are laid in clusters of 18 to 30, and held together by a film of mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
. The egg masses are about 3.5 x 2 cm in overall size.
The eggs are very large compared with the size of the animal, but vary within certain limits. The largest eggs are more elongate, being 8.5 × 4.25 mm; the smallest eggs are more regularly oval, and are only 6 × 3 mm. All are semitranslucent milky-white or opalescent when fresh, although some of the larger and more elongate ones show a somewhat transparent area at the smaller end. The opalescent lustre becomes lost in a few days, and the eggs turn yellowish, and later brown, or black.
The young appear to hatch in from 6 to 8 weeks, at which period the spots on the body of the animal are barely present, but the lateral bands are distinct and black, much more conspicuous than they are in mature slugs of this species. In juveniles the shield shows lyre
Lyre
The lyre is a stringed musical instrument known for its use in Greek classical antiquity and later. The word comes from the Greek "λύρα" and the earliest reference to the word is the Mycenaean Greek ru-ra-ta-e, meaning "lyrists", written in Linear B syllabic script...
-shaped markings, as is the case in slugs of the genus Arion. However these lyre-shaped markings become indistinct as the slugs grow larger. The slugs probably pass the winter in the immature
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
stage. The body of preserved
Preservative
A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes....
juvenile specimens is up to 3 cm (1.2 in) long with a mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
length of 10 mm.
Juveniles reach maturity in 2 years, at a length about 2.6 cm.
The life span of Geomalacus maculosus in the wild is up to seven years, but the lifespan in captivity is rarely over three years.
In numerous different localities in Spain, it was consistently the case that no more than a very few individuals of the species were observed.
Threats to the survival of the species
The most serious threat to the species is probably modification of the habitatHabitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
, which reduces its lichen and moss food sources. This can lead to the local disappearance of the species, which was documented in Spain. Other threats include: intensification of land use (land reclamation
Land reclamation
Land reclamation, usually known as reclamation, is the process to create new land from sea or riverbeds. The land reclaimed is known as reclamation ground or landfill.- Habitation :...
, using of pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s, overgrazing by sheep, removing of shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s, building gardens, burning, and building roads and highways), tourism
Tourism
Tourism is travel for recreational, leisure or business purposes. The World Tourism Organization defines tourists as people "traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".Tourism has become a...
, general development pressure, coniferous forest plantations, the spread of invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
of plants such as Rhododendron ponticum
Rhododendron ponticum
Rhododendron ponticum, called Common Rhododendron or Pontic Rhododendron, is a species of Rhododendron native to southern Europe and southwest Asia.-Description:...
and habitat fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
(see also Moorkens 2006).
Other potential dangers to the species include climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
and air pollution
Air pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
, because these negatively affect the lichens which are a food source for the slug. Climate change will probably affect the Iberian populations more seriously, because the climate there is already on the hot and dry side relative to Ireland, which is generally rather cool and damp.
International protection
Because of its perceived rarity and its restricted distribution, Geomalacus maculosus is protected under the Convention on the Conservation of European Wildlife and Natural HabitatsConvention on the Conservation of European Wildlife and Natural Habitats
The Bern Convention on the Conservation of European Wildlife and Natural Habitats 1979, also known as the Bern Convention , came into force on June 1, 1982....
(Bern Convention), EIS Bern Invertebrates Project. This decision was backed by studies of its distribution and ecology
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
in Ireland which concluded that evidence of a decline in Iberia plus uncertainty over its status in Ireland supported its inclusion in the Convention.
Since 2006, Geomalacus maculosus has been considered as least concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
species in the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
, however during 1994 to 2006 it was considered to be vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
.
Geomalacus maculosus is also protected by the European Union's Habitats Directive (which was a response to the Bern Convention) and has been listed as an Annex II and Annex IV species since 1992. There are two principal mechanisms used by the Directive to protect habitats and species – the creation of Special Areas of Conservation (SACs) and the protection of species independently of their habitats by other means. It is probably in areas not specifically protected as SACs that threats to the Kerry slug will be greatest.
Seven SACs have been designated for this species in Ireland and 49 SCIs in Spain.
The Habitats Directive protects the Kerry slug outside the SACs by Article 12 (1), which obliges EU member states:
- to establish ‘a system of strict protection’ for listed species
- to prohibit deliberate capture or killing
- to prohibit ‘deliberate disturbance … particularly during the period of breeding, rearing, hibernation and migration’
- to prohibit ‘deliberate destruction or taking of eggs from the wild’
- to prohibit the deliberate or non-deliberate ‘deterioration or destruction of breeding sites or resting places’.
Protection in Iberia
Conservation status reports from Portugal and from Spain were not yet available in August 2009.Its conservation status in Spain for the IUCN criteria is vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
.
Protection in Ireland
In 1988 Platts and Speight noted that only three of the Irish sites where the slug occurred were protected: Glengariff ForestGlengariff Forest
Glengarriff Forest is an area of woodland near Glengarriff, West Cork, Ireland. Most of the woodland is a nature reserve in public ownership which is sometimes referred to as Glengarriff "forest park" or "state forest"....
, West Cork
West Cork
West Cork refers to a geographical area in south-west Ireland, lying within Ireland's largest county, County Cork. Traditionally a popular tourist destination, the area is seen as being distinct from the more populated northern or eastern parts of the county, as well as the more urban area of...
; Uragh Wood Nature Reserve
Uragh Wood
Uragh Wood is an oak wood in Tuosist, County Kerry, southwestern Ireland, which was designated a nature reserve in 1982. The wood covers about 80 ha and is next to Gleninchaquin Lake...
, South Kerry; and Killarney National Park
Killarney National Park
Killarney National Park is located beside the town of Killarney, County Kerry, Ireland. It was the first national park established in Ireland, created when Muckross Estate was donated to the Irish state in 1932...
, North Kerry. They concluded that the species could not be adequately safeguarded with only three sites, and therefore they supported its inclusion in the Bern list, to which the Irish government is a signatory.
The Habitats Directive was transposed
Transposition (law)
The incorporation of international law is the process by international agreements become part of the municipal law of a sovereign state. A country incorporates a treaty by passing domestic legislation that gives effect to the treaty in the national legal system....
into Irish law
Law of the Republic of Ireland
The law of the Republic of Ireland consists of constitutional, statute and common law. The highest law in the Republic is the Constitution of Ireland, from which all other law derives its authority...
by:
- The EC (Natural Habitats) Regulations 1997. This was the principal legislation transposing the Habitats Directive and upgraded the protection of the Kerry slug's habitat by the designation of Special Areas of Conservation (as listed in the distribution section above).
- Adapting existing legislation. The Kerry slug has been protected since 1990 under the Irish Wildlife Act of 1976; it was added to the list of protected species by Statutory InstrumentStatutory InstrumentA Statutory Instrument is the principal form in which delegated or secondary legislation is made in Great Britain.Statutory Instruments are governed by the Statutory Instruments Act 1946. They replaced Statutory Rules and Orders, made under the Rules Publication Act 1893, in 1948.Most delegated...
112/1990, and was the only gastropod so protected. The Wildlife Act does not protect the slug from authorised or unauthorised indirect damage, but only from wilful direct damage such as collecting.
The Irish National Parks and Wildlife Service
National Parks and Wildlife Service (Ireland)
The National Parks and Wildlife Service manages the Irish State's nature conservation responsibilities. It is part of the Department of the Environment, Heritage and Local Government....
published a Species Action Plan for the Kerry slug in January 2008. This Action Plan was superseded in May 2010 by a Threat Response Plan, which addressed issues arising from a legal challenge to Ireland's transposition and implementation of the Habitats Directive.
Monitoring
In a report to the European CommissionEuropean Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
covering 1988–2007, the conservation status of the species in Ireland was declared "favourable (FV)" in all evaluated criteria (range, population, habitat and future prospects).However, in 2007 the European Court of Justice
European Court of Justice
The Court can sit in plenary session, as a Grand Chamber of 13 judges, or in chambers of three or five judges. Plenary sitting are now very rare, and the court mostly sits in chambers of three or five judges...
took the view that Ireland was not monitoring the species properly.
This point was conceded by the Threat Response Plan of 2010, which noted that population statistics were still deficient, particularly outside the SACs, and examined how monitoring of the species might be improved. As the Threat Response Plan noted, species monitoring is a process in which distribution and status of the subject are evaluated systematically over time. Under this definition no monitoring of the Kerry Slug had yet been undertaken in Ireland as at May 2010.
The Kerry Slug Survey of Ireland, a collaboration between the National Parks and Wildlife Service and the Applied Ecology Unit at the National University of Ireland, Galway
National University of Ireland, Galway
The National University of Ireland, Galway is a constituent university of the National University of Ireland...
, was working in 2010 on a "suitable monitoring protocol", which was due to be published by 2011.
Captive breeding
Since 1990, the species has been successfully bred in captivity. The Wildfowl & Wetlands Trust, a British conservation organisation, operates a captive breedingCaptive breeding
Captive breedingis the process of breeding animals in human controlled environments with restricted settings, such as wildlife reserves, zoos and other conservation facilities; sometimes the process is construed to include release of individual organisms to the wild, when there is sufficient...
programme in terraria at its "Endangered Species Breeding Unit". The project is located not within the species' normal range, but in England at the Martin Mere Wetland Centre
WWT Martin Mere
WWT Martin Mere is a wetland nature reserve managed by the Wildfowl and Wetlands Trust at Tarlscough, Burscough, Lancashire, England, on the West Lancashire Coastal Plain, from Ormskirk and from Southport...
. During the 1990s, slugs from the breeding programme were given out to a number of different zoos and individuals in order to set up their own breeding programmes, but unfortunately only a very few of those breeding groups survived.
Further reading
- Allman, G. J. (1844). "On a new genus of terrestrial gastropod". Report of the British Association for the Advancement of ScienceBritish Association for the Advancement of Scienceframe|right|"The BA" logoThe British Association for the Advancement of Science or the British Science Association, formerly known as the BA, is a learned society with the object of promoting science, directing general attention to scientific matters, and facilitating interaction between...
1843: 77. - Allman, G. J. (1846). "Description of a new genus of pulmonary gastropods". Annals and Magazine of Natural History 17: 297–299, plate 9.
- Boycott, A. E. & Oldham, C. (1930). "The food of Geomalacus maculosus". Journal of Conchology 19: 36.
- Oldham, C. (1942). "Notes on Geomaculus maculosus". Proceedings of The Malacological Society of London 25.
- Heynemann, D. F. (1873). "On the French species of the genus Geomalacus". Annals and Magazine of Natural History, pages 271–275. Heynemann, D. F. (1869). "Zur Kenntniss von Geomalacus". Nachrichtsblatt der Deutschen Malakozoologischen Gesellschaft, pages 165–168. Heynemann, D. F. (1871). "Geomalacus maculosus". Nachrichtsblatt der Deutschen Malakozoologischen Gesellschaft 3(1): 126. Heynemann, D. F. (1873). "Ueber Geomalacus". Malakozoologische Blätter xxi: 25–36, table 1, fig. 1-6.
- Moorkens, E. A. (2006). "Irish non-marine molluscs – an evaluation of species threat status". Bulletin of the Irish Biogeographical Society 30: 348–371. ISSN 0032-1185.
- Scharff, R. F. (1892). "Land and freshwater shells peculiar to the British Isles". NatureNature (journal)Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
, 46(1178): 173. - Scharff, R. F. (1893). "Note on the geographical distribution of Geomalacus maculosus Allman, in Ireland". Proceedings of the Malacological Society of London, volume I, 1893–1895, 17–18.
External links
- Campaign to Save Otter and the Kerry Slug, article from the MailDaily MailThe Daily Mail is a British daily middle-market tabloid newspaper owned by the Daily Mail and General Trust. First published in 1896 by Lord Northcliffe, it is the United Kingdom's second biggest-selling daily newspaper after The Sun. Its sister paper The Mail on Sunday was launched in 1982...
. - Bridges & Species: Post-Glacial Colonisation
- A photograph of a live individual
- Public Consultation Kerry Slug and Otter: (6 August 2009) Forestry and Kerry Slug Guidelines (draft). Forest Service Department of Agriculture, Fisheries and Food