The Noronha skinkRocha et al., 2009, p. 450; Sazima et al., 2005, p. 2; Silva et al., 2005, p. 62; Sazima et al., 2005, p. 1 (Trachylepis atlantica) is a species of skink from the island of Fernando de Noronha off northeastern Brazil. It is covered with dark and light spots on the upperparts and is usually about 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 insects and plant material, including nectar from the Erythrina velutina tree, as well as other material ranging from cookie crumbs to eggs of its own species. Introduced predators such as feral cats prey on it and several parasitic worms infect it.
Perhaps seen by Amerigo Vespucci in 1503, it was first formally described in 1839. Its subsequent taxonomic history has been complex, riddled with confusion with Trachylepis maculata and other species, homonyms, and other problems. The species is classified in the otherwise mostly African genus Trachylepis and is thought to have reached its island from Africa by rafting. The enigmatic Trachylepis tschudii, supposedly from Peru, 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 in 1503, the island was said to be inhabited by "lizards with two tails", which is thought be a reference to the Noronha skink.Carleton and Olson, 1999, p. 48 The tail is long and fragile, and it breaks easily, like that of many skinks and other lizards, following which it may regenerate. 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 in 1839, based on two specimens collected by HMS Chanticleer before 1838.Schmidt, 1945, p. 45; Mausfeld and Vrcibradic, 2002, p. 292 He introduced the names Tiliqua punctata, for the Noronha skink, and Tiliqua maculata, for a species from Guyana, among many others.Gray, 1839, p. 289 Six years later, he transferred both to the genus Euprepis. In 1887, George Boulenger placed both in the genus Mabuya (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 O'Shaughnessy, 1874, purportedly from South Africa, as a synonym.Boulenger, 1887, pp. 160–161 In 1874, A.W.E. O'Shaughnessy described the new species Mabouya punctatissima on the basis of a specimen, purchased from a Mr. Parzudaki, which had been labeled as coming from the Cape of Good Hope, a location O'Shaughnessy considered "very doubtful".O'Shaughnessy, 1874, p. 300. G.A. Boulenger, in 1887 synonymized it under Mabuia punctata (the Noronha skink) without comment, a position followed by H. Travassos with some doubt. The latter wrote that the description of punctatissima suggested to him that punctatissima and the Noronha skink are morphologically different, but that Boulenger's examination of the type and the uncertainty of the type locality inclined him to favor the synonymy.Travassos, 1946, pp. 7–8. In 2002, P. Mausfeld and D. Vrcibradic re-examined the holotype, which is the only known specimen. It is similar to T. atlantica, but larger, and lacks well-developed keels on its dorsal scales. Therefore, they suggested that it was not the same as T. atlantica and that its original locality may have been correct. Although it may represent a valid species of southern African Trachylepis, the name Trachylepis punctatissima is preoccupied by Euprepes punctatissimus A. Smith, 1849, also currently placed in Trachylepis.Mausfeld and Vrcibradic, 2002, p. 294.
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.Mausfeld and Vrcibradic, 2002, p. 292 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.Bauer, 2003, p. 4 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.Dunn, 1935, pp. 535–536 He wrote that the Noronha skink was very distinct from other American Mabuya and more similar in some respects to African species.Dunn, 1935, p. 536
Karl Patterson Schmidt, 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.Schmidt, 1945, p. 45 The next year, H. Travassos, disagreeing with Dunn and unaware of Andersson's and Schmidt's contributions,Travassos, 1948, p. 201 considered both of Gray's names to be synonymous and restored the name Mabuya punctata for the Noronha skink.Travassos, 1946, pp. 6–7 He also considered Mabouya punctatissima and Trachylepis (Xystrolepis) punctata Tschudi, 1845, described from Peru, as synonyms of this species.Travassos, 1946, pp. 7–8 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.Travassos, 1948, p. 206 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.Mausfeld and Vrcibradic, 2002, p. 293 Based on differences in the number of scales, subdigital lamellae (lamellae on the lower sides of the digits), and keels (longitudinal ridges) on the dorsal scales (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 12S and 16S rRNA genes, and showed that the species is more closely related to African than to South American Mabuya species,Mausfeld et al., 2002, p. 281 as previously suggested on the basis of morphological similarities.Whiting et al., 2006, pp. 720–721 They split the old genus Mabuya into four genera for geographically discrete clades, including Euprepis for the African–Noronha clade, thus renaming the Noronha species to Euprepis atlanticus.Mausfeld et al., 2002, p. 290 In 2003, A.M. Bauer found that the name Euprepis had been incorrectly applied to this clade and that Trachylepis was correct instead, so that the Noronha skink is currently referred to as Trachylepis atlantica.Bauer, 2003, p. 5Bauer, 2003, p. 5, corrected the generic name from Euprepis to Trachylepis, but did not explicitly use the name combination Trachylepis atlantica, which was first used by Ananjeva et al., 2006, p. 76. Additional molecular phylogenetic studies published in 2003 and 2006 confirmed the relationship between the Noronha skink and African Trachylepis.Carranza and Arnold, 2003; Whiting et al., 2006
In 2009, Miralles and others reviewed the taxon maculata and concluded that the animal now known as Trachylepis maculata also belongs in the African clade, but they were unable to determine whether or not it is indigenous to Guyana.Miralles et al., 2009, p. 62 They also reviewed Trachylepis (Xystrolepis) punctata and replaced it with Trachylepis tschudii because the older name was preoccupied by Linnaeus's and Gray's punctata.Miralles et al., 2009, p. 57 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.Miralles et al., 2009, p. 58
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.Dunn, 1935, p. 536; Mausfeld and Vrcibradic, 2002, p. 293; Finley, 1945, p. 164 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. There are three to five well-developed auricular lobules (small projections) in front of the ears; these lobules are absent in true Mabuya.Dunn, 1935, p. 536; Miralles et al., 2009, p. 57 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.Travassos, 1946, p. 8
In reptiles, features of the scales 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 (behind the nose) in most individuals. The two frontoparietal scales (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 (above the eyes) in almost all specimens and five supraciliary scales (immediately above the eyes, below the supraoculars). The dorsal scales (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 scales (on the underparts).Travassos, 1946, pp. 26–28; summarized in Mausfeld and Vrcibradic, 2002, table 1; nomenclature from Avila-Pires, 1995, pp. 9–10; Schleich et al., 1996, p. 372 Mabuya species and T. maculata generally have fewer midbody scales (up to 34).Dunn, 1935, p. 536; Mausfeld and Vrcibradic, 2002, pp. 293–294; Miralles et al., 2009, p. 65 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), similar to most Trachylepis, but unlike American Mabuya, which have at least 28.Greer et al., 2000, table 1