The Noronha skink (Trachylepis atlantica) is a species

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 skink

Skink

Skinks are lizards belonging to the family Scincidae. Together with several other lizard families, including Lacertidae , they comprise the superfamily or infraorder Scincomorpha...

 from the island of Fernando de Noronha

Fernando de Noronha

Fernando de Noronha is an archipelago of 21 islands and islets in the Atlantic Ocean, offshore from the Brazilian coast. The main island has an area of and had a population of 3,012 in the year 2010...

 off northeastern Brazil. It is covered with dark and light spots on the upperparts and is usually about 7 to 10 cm (3 to 4 in) in length. The tail is long and muscular, but breaks off easily. Very common throughout Fernando de Noronha, it is an opportunistic feeder, eating both insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s and plant material, including nectar from the Erythrina velutina

Erythrina velutina

Erythrina velutina is a species of leguminous tree. It is indigenous to Brazil, Peru, Ecuador, Colombia, Venezuela, and Hispaniola and has been introduced to much of the Caribbean, Uganda, and Sri Lanka. It also occurs on the Galápagos Islands, but whether it is indigenous or introduced there is...

tree, as well as other material ranging from cookie crumbs to eggs of its own species. Introduced

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

 predators

Predation

In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

 such as cat

Cat

The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

s can prey on it and several parasitic worm

Parasitic worm

Parasitic worms or helminths are a division of eukaryoticparasites that, unlike external parasites such as lice and fleas, live inside their host. They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient...

s infect it.

Perhaps seen by Amerigo Vespucci

Amerigo Vespucci

Amerigo Vespucci was an Italian explorer, financier, navigator and cartographer. The Americas are generally believed to have derived their name from the feminized Latin version of his first name.-Expeditions:...

 in 1503, it was first formally described in 1839. Its subsequent taxonomic

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 history has been complex, riddled with confusion with Trachylepis maculata

Trachylepis maculata

Trachylepis maculata is a species of skink in the genus Trachylepis recorded from Demerara in Guyana, northern South America. It is placed in the genus Trachylepis, which is otherwise mostly restricted to Africa, and its type locality may be in error. It is an unstriped, olive-brown, grayish...

and other species, homonyms, and other problems. The species is classified in the otherwise mostly African genus Trachylepis

Trachylepis

Trachylepis is a skink genus in the subfamily Lygosominae found mainly in Africa. Its members were formerly included in the "wastebin taxon" Mabuya, and for some time in Euprepis. As defined today, Trachylepis contains the clade of Afro-Malagasy mabuyas. The genus also contains a species from the...

and is thought to have reached its island from Africa by rafting

Rafting event

Oceanic dispersal is a type of biological dispersal that occurs when organisms transfer from one land mass to another by way of a sea crossing on large clumps of floating vegetation. Such matted clumps of vegetation are often seen floating down major rivers in the tropics and washing out to sea,...

. The enigmatic Trachylepis tschudii

Trachylepis tschudii

Trachylepis tschudii is an enigmatic skink, purportedly from Peru. First described in 1845 on the basis of a single specimen, it may be the same as the Noronha skink from Fernando de Noronha, off northeastern Brazil...

, supposedly from Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, may well be the same species.

Discovery and taxonomy

In an early account of what may be Fernando de Noronha, purportedly based on a voyage by Amerigo Vespucci

Amerigo Vespucci

Amerigo Vespucci was an Italian explorer, financier, navigator and cartographer. The Americas are generally believed to have derived their name from the feminized Latin version of his first name.-Expeditions:...

 in 1503, the island was said to be inhabited by "lizards with two tails", which is thought be a reference to the Noronha skink. The tail is long and fragile, and it breaks easily, like that of many skinks and other lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s, following which it may regenerate

Regeneration (biology)

In biology, regeneration is the process of renewal, restoration, and growth that makes genomes, cells, organs, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. At its most...

. However, when it does not completely break off, a new tail may nevertheless grow out of the broken part, so that the tail appears forked.

19th century

The species was first formally described by John Edward Gray

John Edward Gray

John Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ....

 in 1839, based on two specimens collected by HMS Chanticleer

HMS Chanticleer (1808)

HMS Chanticleer was a Cherokee-class 10-gun brig of the Royal Navy. Chanticleer was launched on 26 July 1808. She served in European waters during the Napoleonic Wars and was paid off and laid up at Sheerness in July 1816. She was chosen for an 1828 scientific voyage to the Pacific Ocean...

 before 1838. He introduced the names Tiliqua punctata, for the Noronha skink, and Tiliqua maculata, for a species from Guyana

Guyana

Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...

, among many others. Six years later, he transferred both to the genus Euprepis. In 1887, George Boulenger

George Albert Boulenger

George Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...

 placed both in the genus Mabuya

Mabuya

Mabuya is a genus of long-tailed skinks nowadays restricted to species from the Americas. The American mabuyas are primarily carnivorous, though many are omnivorous. Formerly, many Old World species were placed here, as Mabuya was a kind of "wastebasket taxon"...

(misspelled "Mabuia") and considered them identical, using the name "Mabuia punctata" for the species, which was said to occur both on Fernando de Noronha and in Guyana. He also included Mabouya punctatissima

Mabouya punctatissima

Mabouya punctatissima is a skink described in 1872 on the basis of a single specimen. It was said to be from South Africa, but later researchers doubted that origin and aligned the species with the Noronha skink from Fernando de Noronha, off northeastern Brazil, instead...

O'Shaughnessy, 1874, purportedly from South Africa, as a synonym

Synonym (taxonomy)

In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...

.

20th century

In 1900, L.G. Andersson claimed that Gray's name punctata was preoccupied by Lacerta punctata Linnaeus, 1758, which he identified as Mabuya homalocephala. He therefore replaced the name punctata with its junior synonym maculata, using the name Mabuya maculata for the skink of Fernando de Noronha. Linnaeus's Lacerta punctata in fact refers to the Asian species Lygosoma punctatum, not to Mabuya homalocephala, but Gray's name punctata remains invalid regardless. In 1931, C.E. and M.D. Burt resurrected the name Mabuya punctata (now spelled correctly) for the Noronha skink, noting that it was "apparently a very distinct species", but did not mention maculata, and in 1935, E.R. Dunn disputed Boulenger's conclusion as to the synonymy of punctata and maculata and, in apparent ignorance of Andersson's work, restored the name Mabuya punctata for the Noronha skink. He wrote that the Noronha skink was very distinct from other American Mabuya and more similar in some respects to African species.

K.P. Schmidt

Karl Patterson Schmidt

Karl Patterson Schmidt was an American herpetologist.-Biography:Schmidt was the son of George W. Schmidt and Margaret Patterson Schmidt. Schmidt's father was a German professor who, at the time of Schmidt's birth, was teaching in Lake Forest, Illinois. His family left the city in 1907 and settled...

, in 1945, agreed with Dunn's conclusion that maculata and punctata of Gray were not the same, but he noted Andersson's point that punctata was preoccupied and therefore introduced the new name Mabuya atlantica to replace punctata. The next year, H. Travassos, disagreeing with Dunn and unaware of Andersson's and Schmidt's contributions, considered both of Gray's names to be synonymous and restored the name Mabuya punctata for the Noronha skink. He also considered Mabouya punctatissima and Trachylepis (Xystrolepis) punctata Tschudi

Johann Jakob von Tschudi

Johann Jakob von Tschudi was a Swiss naturalist and explorer.Tschudi was born in Glarus, and studied natural sciences and medicine at the universities of Neuchâtel, Leiden and Paris. In 1838 he travelled to Peru, where he remained for five years exploring and collecting plants in the Andes...

, 1845, described from Peru, as synonyms of this species. In 1948, he acknowledged the preoccupation of punctata noted by Andersson and accordingly retired Mabuya punctata in favor of Mabuya maculata, as Andersson had done. The name Mabuya maculata remained in general usage for the Noronha skink in subsequent decades, though some have used Mabuya punctata, "not ... aware of the last nomenclatural changes."

21st century

In 2002, P. Mausfeld and D. Vrcibradic published a note on the nomenclature of the Noronha skink informed by a re-examination of Gray's original type specimens; despite extensive attempts to correctly name the species, they were apparently the first to do so since Boulenger in 1887. Based on differences in the number of scales

Scale (zoology)

In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...

, subdigital lamellae (lamellae on the lower sides of the digits), and keels (longitudinal ridges) on the dorsal scales

Dorsal scales

In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales.When counting dorsal scales, numbers are often given for three points along the body, for example 19:21:17...

 (located on the upperparts), as well as the separation of the parietal scales (on the head behind the eyes) in maculata, they concluded that the two were not, after all, identical, and that Schmidt's name Mabuya atlantica should therefore be used. Mausfeld and Vrcibradic considered Mabouya punctatissima to represent a different species on the basis of morphological differences, but were unable to resolve the status of Trachylepis (Xystrolepis) punctata.

In the same year, Mausfeld and others conducted a molecular phylogenetic study on the Noronha skink, using the mitochondrial

Mitochondrial DNA

Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...

 12S and 16S rRNA

16S ribosomal RNA

16S ribosomal RNA is a component of the 30S subunit of prokaryotic ribosomes. It is approximately 1.5kb in length...

 genes, and showed that the species is more closely related to African than to South American Mabuya species, as previously suggested on the basis of morphological similarities. They split the old genus Mabuya into four genera for geographically discrete clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

s, including Euprepis for the African–Noronha clade, thus renaming the Noronha species to Euprepis atlanticus. In 2003, A.M. Bauer found that the name Euprepis had been incorrectly applied to this clade and that Trachylepis

Trachylepis

Trachylepis is a skink genus in the subfamily Lygosominae found mainly in Africa. Its members were formerly included in the "wastebin taxon" Mabuya, and for some time in Euprepis. As defined today, Trachylepis contains the clade of Afro-Malagasy mabuyas. The genus also contains a species from the...

was correct instead, so that the Noronha skink is currently referred to as Trachylepis atlantica. Additional molecular phylogenetic studies published in 2003 and 2006 confirmed the relationship between the Noronha skink and African Trachylepis.

In 2009, Miralles and others reviewed the taxon maculata and concluded that the animal now known as Trachylepis maculata

Trachylepis maculata

Trachylepis maculata is a species of skink in the genus Trachylepis recorded from Demerara in Guyana, northern South America. It is placed in the genus Trachylepis, which is otherwise mostly restricted to Africa, and its type locality may be in error. It is an unstriped, olive-brown, grayish...

also belongs in the African clade, but they were unable to determine whether or not it is indigenous to Guyana. They also reviewed Trachylepis (Xystrolepis) punctata and replaced it with Trachylepis tschudii

Trachylepis tschudii

Trachylepis tschudii is an enigmatic skink, purportedly from Peru. First described in 1845 on the basis of a single specimen, it may be the same as the Noronha skink from Fernando de Noronha, off northeastern Brazil...

because the older name was preoccupied by Linnaeus's and Gray's punctata. Although they were unable to resolve the identity of T. tschudii, which is still known from a single specimen, they believed that it is most likely the same species as the Noronha skink; it may be either a representative of an undiscovered Amazonian population of the latter or simply a mislabeled animal from Fernando de Noronha.

Description

The Noronha skink is covered with light and dark spots above, but there is substantial variation in the precise colors. There are no longitudinal stripes. The scales on the underparts are yellowish or grayish. The eyelids are white to yellow. It has a small head with small nostrils, which are placed far to the front at the sides of the head. The mouth contains small and conical teeth and a thin but well-developed tongue. The eyes are small and placed laterally and contain dark, rounded irises

Iris (anatomy)

The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...

. There are three to five well-developed auricular lobules (small projections) in front of the ears; these lobules are absent in true Mabuya. The hindlimbs are longer and stronger than the forelimbs, which are small. The tail is longer than the body and is muscular but very brittle. It is nearly cylindrical in form and tapers towards the end.

In reptiles, features of the scales

Scale (zoology)

In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...

 are important in distinguishing among species and groups of species. In the Noronha skink, the supranasal scales (located above the nose) are in contact, as are the prefrontal scales

Prefrontal scales

The prefrontal scales on snakes and other reptiles are the scales connected to the frontals towards the tip of the snout which are in contact with the internasals....

 (behind the nose) in most individuals. The two frontoparietal scale

Frontoparietal scale

In reptiles, the frontoparietal scales are scales located behind the eyes, between the frontal scales to the front and the parietal scales to the back....

s (above and slightly behind the eyes) are not fused. Unlike in T. maculata, the parietal scales (behind the frontoparietals) are in contact with each other. There are four supraocular scales

Supraocular scales

In scaled reptiles, supraocular scales are scales on the crown immediately above the eye. The size and shape of these scales are among the many characteristics used to differentiate species from each another....

 (above the eyes) in almost all specimens and five supraciliary scale

Supraciliary scale

In reptiles, the supraciliary scales are scales located immediately above the eyes, below the supraocular scales....

s (immediately above the eyes, below the supraoculars). The dorsal scales

Dorsal scales

In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales.When counting dorsal scales, numbers are often given for three points along the body, for example 19:21:17...

 (on the upperparts) have three keels, two fewer than in T. maculata. There are 34 to 40 (mode 38) midbody scales (counted around the body midway between the fore- and hindlimbs), 58 to 69 (mode 63–64) dorsal, and 66 to 78 (mode 70) ventral

Ventral scales

In snakes, the ventral scales are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that contacts the paraventral row of dorsal scales on either side...

 scales (on the underparts). Mabuya species and T. maculata generally have fewer midbody scales (up to 34). There are 21 to 29 subdigital lamellae under the fourth toe, more than in T. maculata, which has 18. The Noronha skink has 26 presacral vertebrae (located before the sacrum

Sacrum

In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...

), similar to most Trachylepis, but unlike American Mabuya, which have at least 28.

Although there is substantial variation in measurements within the species, no discrete groups can be detected and it is not possible to separate the sexes unambiguously using measurements alone. Among 15 male and 21 female T. atlantica collected in 2006, snout to vent length was 80.6 to 103.1 mm (3.17 to 4.06 in), averaging 95.3 mm (3.75 in), in males and 65.3 to 88.1 mm (2.57 to 3.47 in), averaging 78.3 mm (3.08 in), in females and body mass was 10.2 to 26.0 g (0.36 to 0.92 oz), averaging 19.0 g (0.67 oz), in males and 6.0 to 15.0 g (0.21 to 0.53 oz), averaging 10.0 g (0.35 oz), in females. Males are significantly larger than females. In 100 specimens collected in 1876, head length was 12.0 to 18.9 mm (0.47 to 0.74 in), averaging 14.8 mm (0.58 in); head width was 7 to 14.4 mm (0.28 to 0.57 in), averaging 9 mm (0.4 in), and tail length was 93 to 170 mm (3.7 to 6.7 in), averaging 117 mm.

Ecology and behavior

The Noronha skink is very abundant throughout Fernando de Noronha, even occurring commonly in houses, and also occurs on the smaller islands that surround the main island of the archipelago. Its abundance may be a result of the absence of ecologically similar competitors. Apart from T. atlantica, the reptile fauna of Fernando de Noronha consists of the indigenous amphisbaenia

Amphisbaenia

The Amphisbaenia are a usually legless suborder of squamates closely related to lizards and snakes. As many species possess a pink body coloration and scales arranged in rings, they have a superficial resemblance to earthworms. They are very poorly understood, due to their burrowing lifestyle...

n Amphisbaena ridleyi

Amphisbaena ridleyi

Amphisbaena ridleyi, known by the common names Ridley's worm lizard or the Noronha worm lizard, is a species of amphisbaenian in the genus Amphisbaena that is endemic to the island of Fernando de Noronha off the coast of Brazil...

and two introduced

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

 lizards, the gecko Hemidactylus mabouia

Tropical house gecko

The Tropical house gecko, Afro-American house gecko or Cosmopolitan house gecko is a species of house gecko native to sub-Saharan Africa...

and the tegu Tupinambis merianae

Argentine Black and White Tegu

The Argentine black and white tegu, , is the largest species of tegu. It is also known as the Argentine giant tegu. It belongs to the teiid family...

.

The species is found in several microhabitats

Habitat

* 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...

, but most often on rocks. Although predominantly ground-dwelling, it is a good climber. Nothing is known about its reproduction except that skinks studied in late October and early November, during the dry season, showed little evidence of reproductive activity. The Noronha skink is oviparous

Oviparity

Oviparous animals are animals that lay eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, reptiles, all birds, the monotremes, and most insects, some molluscs and arachnids....

 (egg-laying), like many Trachylepis, but unlike Mabuya, which are all viviparous (giving live birth).

Trachylepis atlantica is active during the day. Its body temperature averages 32 °C (90 °F), a few degrees higher than the environment temperature. During the day, body temperature peaks at up to 38 °C (100 °F) around midday and is lower earlier and later. In the early morning, the lizard may bask in the sun. During foraging, it spends about 28.4% of its time moving on average, a relatively high value for Trachylepis.

A geologist who visited the island in 1876 noted that the skink is curious and bold:

While seated upon the bare rocks I have often observed these little animals watching me, apparently with as much curiosity as I watched them, turning their heads from side to side as if in an effort to be wise. If I kept quiet for a few minutes they would creep up to me and finally upon me; if I moved, they ran down the faces of the rocks, and turning, stuck their heads above the edges to watch me.

Diet

The Noronha skink is an opportunistic omnivore

Omnivore

Omnivores are species that eat both plants and animals as their primary food source...

 and "thrives on anything edible". Analysis of stomach contents indicates that it mainly eats plant material, at least during the dry period, but it also feeds on insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, including larvae, termite

Termite

Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...

s (Isoptera), ant

Ant

Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s (Formicidae), and beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s (Coleoptera). Its prey is mostly mobile, rather than sedentary, which is consistent with the relatively high proportion of time it spends moving. Related skink species eat mostly insects, but island populations may often be more herbivorous. Animal prey averages 6.9 mm³ in volume, less than in most other Trachylepis.

When the mulungu tree Erythrina velutina

Erythrina velutina

Erythrina velutina is a species of leguminous tree. It is indigenous to Brazil, Peru, Ecuador, Colombia, Venezuela, and Hispaniola and has been introduced to much of the Caribbean, Uganda, and Sri Lanka. It also occurs on the Galápagos Islands, but whether it is indigenous or introduced there is...

blooms during the dry season, Noronha skinks climb up to 12 m (39 ft) to reach the inflorescence

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

s of the tree and to eat the nectar by inserting their heads into the flowers. They probably use the nectar both for its sugar and water content. In this way, the skinks aid in pollinating

Pollination

Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...

 the tree, as they acquire pollen on their scales and leave pollen on stigmas

Stigma (botany)

The stigma is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower. The stigma receives pollen at pollination and it is on the stigma that the pollen grain germinates. The stigma is adapted to catch and trap pollen with various hairs, flaps, or sculpturings...

 when visiting a flower. Pollination is rare behavior among lizards, but occurs most frequently in island species. Humans have introduced additional food sources to the island, including Acacia

Acacia

Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

seeds, feces of the rock cavy

Rock Cavy

The rock cavy or mocó, Kerodon rupestris, is a cavy species endemic to eastern Brazil, from eastern Piauí state to Minas Gerais state...

 (Kerodon rupestris), carrion flies, juvenile Hemidactylus mabouya, and even cookie crumbs given by tourists. The availability of these additional food sources may increase the abundance of the skink. In 1887, H. N. Ridley observed Noronha skinks eating banana skins and yolk from doves' eggs. Several cases of cannibalism

Cannibalism

Cannibalism is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy...

 have been reported, involving skinks eating eggs, juveniles, and the tail of an adult.

Relationships with other species

The Noronha skink probably lacked predators before Fernando de Noronha was discovered by humans, but several species that arrived since do prey on it, most commonly the cat

Cat

The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

 (Felis catus) and cattle egret

Cattle Egret

The Cattle Egret is a cosmopolitan species of heron found in the tropics, subtropics and warm temperate zones. It is the only member of the monotypic genus Bubulcus, although some authorities regard its two subspecies as full species, the Western Cattle Egret and the Eastern Cattle Egret...

 (Bubulcus ibis). These may negatively affect skink abundance at some localities on the island. The Argentine black and white tegu lizard, Tupinambis merianae, and three introduced rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s, the house mouse

House mouse

The house mouse is a small rodent, a mouse, one of the most numerous species of the genus Mus.As a wild animal the house mouse mainly lives associated with humans, causing damage to crops and stored food....

 (Mus musculus), brown rat

Brown Rat

The brown rat, common rat, sewer rat, Hanover rat, Norway rat, Brown Norway rat, Norwegian rat, or wharf rat is one of the best known and most common rats....

 (Rattus norvegicus) and black rat

Black Rat

The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...

 (Rattus rattus), have also been observed to eat Noronha skinks, but the rodents, particularly the house mouse, may have been scavenging on already dead skinks.

According to a 2006 study, the Noronha skink is infected by several parasitic worm

Parasitic worm

Parasitic worms or helminths are a division of eukaryoticparasites that, unlike external parasites such as lice and fleas, live inside their host. They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient...

s, most frequently by the nematode

Nematode

The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...

 Spinicauda spinicauda. Another nematode, Moaciria alvarengai, is much rarer. Other rare parasites include two trematodes

Trematoda

Trematoda is a class within the phylum Platyhelminthes that contains two groups of parasitic flatworms, commonly referred to as "flukes".-Taxonomy and biodiversity:...

—Mesocoelium monas and an undetermined species of Platynossomum—and an undetermined species of Ochorositica, a cestode

Cestoda

This article describes the flatworm. For the medical condition, see Tapeworm infection.Cestoda is the name given to a class of parasitic flatworms, commonly called tapeworms, of the phylum Platyhelminthes. Its members live in the digestive tract of vertebrates as adults, and often in the bodies...

. S. spinicauda is usually only found in teiid

Teiidae

Teiidae is a family of lizards native to the Americas, generally known as whiptails. The group includes the parthenogenic genera Cnemidophorus and Aspidoscelis, and the non-parthenogenic Tupinambis. It has over 230 member species in ten genera...

 lizards; it may have entered the archipelago when Tupinambis merianae, a teiid, was introduced to the island in 1960. Among nematodes, previous studies in 1956 and 1957 had only reported M. alvarengai and Thelandros alvarengai from the skink; the presence of S. spinicauda could explain the rarity of M. alvarengai and absence of T. alvarengai in Noronha skinks observed in 2006.

Origin

Phylogenetic

Cladistics

Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 analyses using a variety of mitochondrial

Mitochondrial DNA

Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...

 and nuclear

Nuclear DNA

Nuclear DNA, nuclear deoxyribonucleic acid , is DNA contained within a nucleus of eukaryotic organisms. In mammals and vertebrates, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than...

 genes places the Noronha skink among the tropical African species of Trachylepis, a position also supported by morphological similarities. It may have arrived on its island on rafting vegetation

Rafting event

Oceanic dispersal is a type of biological dispersal that occurs when organisms transfer from one land mass to another by way of a sea crossing on large clumps of floating vegetation. Such matted clumps of vegetation are often seen floating down major rivers in the tropics and washing out to sea,...

 from southwestern Africa via the Benguela Current

Benguela Current

The Benguela Current is the broad, northward flowing ocean current that forms the eastern portion of the South Atlantic Ocean gyre. The current extends from roughly Cape Point in the south, to the position of the Angola-Benguela Front in the north, at around 16°S. The current is driven by the...

 and the South Equatorial Current

South Equatorial Current

The South Equatorial Current is a significant Pacific, Atlantic, and Indian Ocean current that flows east-to-west between the equator and about 20 degrees south. In the Pacific and Atlantic Oceans, it extends across the equator to about 5 degrees north....

, which passes Fernando de Noronha. This possibility was first suggested by Alfred Russel Wallace

Alfred Russel Wallace

Alfred Russel Wallace, OM, FRS was a British naturalist, explorer, geographer, anthropologist and biologist...

 before 1888. Mausfeld and coworkers calculated that the journey from Africa to Fernando de Noronha would take 139 days. Because this period seemed too long for the skink to survive, they proposed that the Noronha skink instead arrived via Ascension Island

Ascension Island

Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...

, where a skink may have persisted into historical times.

The South American and Caribbean Mabuya

Mabuya

Mabuya is a genus of long-tailed skinks nowadays restricted to species from the Americas. The American mabuyas are primarily carnivorous, though many are omnivorous. Formerly, many Old World species were placed here, as Mabuya was a kind of "wastebasket taxon"...

skinks form a clade that appears to be derived from a separate colonization from Africa. Both transatlantic colonization

Colonisation (biology)

Colonisation is the process in biology by which a species spreads into new areas, regions, and continents. It is sometimes also referred to as immigration, but colonisation often refers to successful immigration with integration to a community, having resisted initial local extinction.One classic...

events are believed to have occurred within the last 9 million years.

Literature cited

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