Gulella systemanaturae
Encyclopedia
Gulella systemanaturae is a species
of minute air-breathing land snail
, a terrestrial
pulmonate gastropod mollusk in the family Streptaxidae
.
Gulella systemanaturae was described by Adolph Cornelis van Bruggen
in 2008 based on collections from 1975 in Royal Museum for Central Africa
, Tervuren
, Belgium and 1985 collection in Nationaal Natuurhistorisch Museum, Leiden.
The specific name systemanaturae was given in honor of the 250th anniversary of the publication of Linnaeus’ book, Systema Naturae
.
in South-Central Malawi
.
with little prominent costulation, seven to seven and three-quarter whorls
and fourfold apertural dentition consisting of angular lamella, labral process, and outer and inner columellar processes; labrum sharply angulate at its point of attachment to the body whorl near the angular lamella.
The shell is medium-sized, cylindriform to subcylindriform, greatest width at about the middle of the shell, glossy and transparent when fresh, with narrowly open umbilicus to more or less rimate. Spire
produced, sides straight to very slightly convex and (sub)parallel, apex
obtusely conical. Whorls seven to seven and three-quarters, very slightly convex, covered with fairly close, straight, oblique and little prominent costulae, interstices wider than (at most as wide as) costulae, smooth but with clear traces of spiral sculpture, apical whorls smooth with faint traces of spiral engraving; sutures fairly shallow to somewhat incised, crenellate. Labrum incrassate and reflected, sharply angulate at its point of attachment to the body whorl near the angular lamella. The aperture
is fairly large, roughly triangular in shape, little obstructed by fourfold dentition: a strong, almost perpendicular, inrunning angular lamella, (almost) free from apex of labrum; a more or less horizontal, triangular mid-labral process, protruding as far as angular lamella, corresponding to noticeable outside depression; a small, but noticeable superficial tubercle above or on the middle of the columella; a deeply situated, little prominent, almost vertical, inside columellar process.
The width of the shell is 3.2-3.6 mm mm. The height of the shell is 7.1-8.2 mm. The ratio length/major diameter of shells is 2.05-2.50. The length of the last whorl is 3.7-4.2 mm. The height of the aperture is 2.4-3.0 mm. The width of the aperture is 2.1-2.5 mm. The shell has 7-7¾ whorls.
The species is particularly characterized by its double columellar processes in the apertural dentition, a splendid discriminating character in shell morphology in this group. In addition, the labrum is sharply angulate at its point of attachment to the body whorl near the angular lamella. This may be an overlooked character as this has not been checked or noticed in other taxa with similar types of shell until the type description of Gulella systemanaturae. Also, sometimes the labrum is very slightly concave where it joins the body whorl on the columellar side.
forest in the Dedza Mountain in altitudes approximately from 1700 m to 2100 m above sea level.
According to Chapman & White (1970) all localities where the Gulella systemanaturae has been found are above the Brachystegia
woodland belt. Chapman & White (1970: 147-151) well described forest habitats of Dedza Mountain. The colour photo on the top of p. 34 in Dowsett-Lemaire & Dowsett (2006) gives a good impression of the area, depicting “Low-canopy montane forest near the summit of Dedza Mountain (2150 m).”. In view of the geographic position of Dedza Mountain it is not unlikely for the species to occur in neighbouring Mozambique
as well.
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 minute air-breathing land snail
Land snail
A land snail is any of the many species of snail that live on land, as opposed to those that live in salt water and fresh water. Land snails are terrestrial gastropod mollusks that have shells, It is not always an easy matter to say which species are terrestrial, because some are more or less...
, 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 mollusk in the family Streptaxidae
Streptaxidae
Streptaxidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in theStylommatophora. Six Streptaxidae subfamilies are accepted in the 2005 taxonomy of the Gastropoda by Bouchet & Rocroi....
.
Gulella systemanaturae was described by Adolph Cornelis van Bruggen
Adolph Cornelis van Bruggen
Adolph Cornelis van Bruggen, also known as A. C. van Bruggen or Dolf van Bruggen is a malacologist, entomologist and botanist from the Netherlands. His interest in the tropics and tropical Africa has dominated his broad scientific interest for more than 50 years now...
in 2008 based on collections from 1975 in Royal Museum for Central Africa
Royal Museum for Central Africa
The Royal Museum for Central Africa is an ethnographical and natural history museum in Tervuren, just outside Brussels, Belgium. It was first built to show off King Leopold II's Congo Free State for the 1897 World Exhibition. It focuses mainly on Congo, Belgium's former colony...
, Tervuren
Tervuren
Tervuren is a municipality in the province of Flemish Brabant, in Flanders, one of the three regions of Belgium. The municipality comprises the villages of Duisburg, Tervuren, Vossem and Moorsel. On January 1, 2006, Tervuren had a total population of 20,636...
, Belgium and 1985 collection in Nationaal Natuurhistorisch Museum, Leiden.
The specific name systemanaturae was given in honor of the 250th anniversary of the publication of Linnaeus’ book, Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
.
Distribution
The type locality is Dedza Mountain in Dedza DistrictDedza District
Dedza is a district in the Central Region of Malawi. It covers an area of 3,624 km.² to the south of the Malawi capital, Lilongwe, between Mozambique and Lake Malawi.-Geography:...
in South-Central Malawi
Central Region, Malawi
The Central Region of Malawi, population 5,491,034 , covers an area of 35,592 km². Its capital city is Lilongwe, which is also the national capital...
.
Shell description
Gulella systemanaturae is characterized by a medium-sized 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...
with little prominent costulation, seven to seven and three-quarter whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
and fourfold apertural dentition consisting of angular lamella, labral process, and outer and inner columellar processes; labrum sharply angulate at its point of attachment to the body whorl near the angular lamella.
The shell is medium-sized, cylindriform to subcylindriform, greatest width at about the middle of the shell, glossy and transparent when fresh, with narrowly open umbilicus to more or less rimate. Spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...
produced, sides straight to very slightly convex and (sub)parallel, apex
Apex (mollusc)
Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...
obtusely conical. Whorls seven to seven and three-quarters, very slightly convex, covered with fairly close, straight, oblique and little prominent costulae, interstices wider than (at most as wide as) costulae, smooth but with clear traces of spiral sculpture, apical whorls smooth with faint traces of spiral engraving; sutures fairly shallow to somewhat incised, crenellate. Labrum incrassate and reflected, sharply angulate at its point of attachment to the body whorl near the angular lamella. The aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is fairly large, roughly triangular in shape, little obstructed by fourfold dentition: a strong, almost perpendicular, inrunning angular lamella, (almost) free from apex of labrum; a more or less horizontal, triangular mid-labral process, protruding as far as angular lamella, corresponding to noticeable outside depression; a small, but noticeable superficial tubercle above or on the middle of the columella; a deeply situated, little prominent, almost vertical, inside columellar process.
The width of the shell is 3.2-3.6 mm mm. The height of the shell is 7.1-8.2 mm. The ratio length/major diameter of shells is 2.05-2.50. The length of the last whorl is 3.7-4.2 mm. The height of the aperture is 2.4-3.0 mm. The width of the aperture is 2.1-2.5 mm. The shell has 7-7¾ whorls.
The species is particularly characterized by its double columellar processes in the apertural dentition, a splendid discriminating character in shell morphology in this group. In addition, the labrum is sharply angulate at its point of attachment to the body whorl near the angular lamella. This may be an overlooked character as this has not been checked or noticed in other taxa with similar types of shell until the type description of Gulella systemanaturae. Also, sometimes the labrum is very slightly concave where it joins the body whorl on the columellar side.
Anatomy
Gulella systemanaturae has red tentacles and cream body. Other detail on anatomy is so far undescribed.Habitat
Gulella systemanaturae was found in leaf litter in SyzygiumSyzygium
Syzygium is a genus of flowering plants that belongs to the myrtle family, Myrtaceae. The genus comprises about 1100 species, and has a native range that extends from Africa and Madagascar through southern Asia east through the Pacific...
forest in the Dedza Mountain in altitudes approximately from 1700 m to 2100 m above sea level.
According to Chapman & White (1970) all localities where the Gulella systemanaturae has been found are above the Brachystegia
Brachystegia
Brachystegia is a genus of tree of the sub-family Caesalpinioideae that is native to tropical Africa. Trees of the genus are commonly known as Miombo, and are the predominant tree in the Miombo woodlands of central and southern Africa.-Species:...
woodland belt. Chapman & White (1970: 147-151) well described forest habitats of Dedza Mountain. The colour photo on the top of p. 34 in Dowsett-Lemaire & Dowsett (2006) gives a good impression of the area, depicting “Low-canopy montane forest near the summit of Dedza Mountain (2150 m).”. In view of the geographic position of Dedza Mountain it is not unlikely for the species to occur in neighbouring Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
as well.