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 ("T. atlantica") from Fernando de Noronha, off northeastern Brazil. "T. tschudii" represents one of two doubtful records of the otherwise African genus "Trachylepis" on mainland South America; the other is "T. maculata" from Guyana. The only specimen, the holotype, is mostly brownish above, with dark and light spots, and white below. The snout-to-vent length is 83 mm (3.3 in). Several features of the scales align it with  Trachylepis over the related American genus "Mabuya". Taxonomy. In 1845, Swiss zoologist Johann Jakob von Tschudi described the new species "Trachylepis (Xystrolepis) punctata" among other species he had collected in Peru. The species was recorded as being from the "forest region" (Amazonia) of Peru and was known from a single specimen, the holotype. In 1887, G.A. Boulenger placed it at an uncertain position within the genus "Mabuia", which included Tschudi's "Trachylepis". In a 1907 reappraisal of some of Tschudi's reptiles and amphibians, J. Roux redescribed "punctata" under the name ""Mabuia punctata"", but did not comment on its affinities . In 1935, E.R. Dunn reviewed some American "Mabuya" and commented that he was unable to tell the identity of "punctata", but that it probably was not a true "Mabuya". Writing in 1946, H. Travassos considered Tschudi's "punctata" to be identical to the Noronha skink (then known as "Mabuya punctata"), a species otherwise known only from Fernando de Noronha, a small archipelago off northeastern Brazil. On the basis of its geographic origin, J. Peters and preferred to place it with one of the "Mabuya" species of Amazonia and classified it as a junior synonym of "Mabuya mabouya". In reviewing the  nomenclature of the Noronha skink, P. Mausfeld and D. Vrcibradic noted in 2002 that Tschudi's name "punctata" was preoccupied within "Mabuya", making it unavailable for use as a valid name. They were unable to examine the holotype and therefore did not comment on its affinities. In the same year, Mausfeld and others split the genus "Mabuya", retaining most American species in "Mabuya" but placing the African species and the Noronha skink in a separate genus "Euprepis"; the latter name was later corrected to "Trachylepis". In 2009, and others reviewed Tschudi's species and re-examined the holotype. Like Mausfeld  and Vrcibradic, they noted that the name "punctata" is preoccupied; earlier uses of the name in "Trachylepis" include "Lacerta punctata" Linnaeus, 1758, which they consider a synonym of "Trachylepis homalocephala" from South Africa, and "Tiliqua punctata" J.E. Gray, 1839, an earlier name for the Noronha skink. (The former was assigned to "Lygosoma punctatum", a member of another skink genus, by Bauer in 2003.) Miralles and coworkers proposed a new name, "Trachylepis tschudii", to replace Tschudi's name "punctata"; the new name honors Tschudi, who first described the animal. They assigned it to the genus "Trachylepis", rather than "Mabuya", on the  basis of several characters of the external anatomy which it shares with the former, but were unable to resolve its placement within "Trachylepis". It is distinct from "T. maculata", a species recorded from Guyana that represents another doubtful mainland South American record of "Trachylepis". They considered three hypotheses: (1) "T. tschudii" is a real, but very rare species from Amazonia; (2) "T. tschudii" is actually from somewhere in the Old World, but its origin was wrongly recorded; and (3) "T. tschudii" represents the same species as the Noronha skink, and it either represents an otherwise unknown Amazonian population of that  species or actually comes from Fernando de Noronha and was mislabeled. Considering the close similarity between "T. tschudii" and the Noronha skink, they considered the third hypothesis to be most likely. Description. The holotype and only known specimen, which is in very poor condition, is preserved in the Museum d'Histoire Naturel de Neuchâtel as specimen MHNN 91.2426. It has five auricular lobules in front of the ears on each side of the head, 39 rows of scales around the midbody, keels on its dorsal scales, and the third supraocular scale in contact with the frontal scale, all characters which align  it with "Trachylepis" rather than "Mabuya". The other putative mainland South American "Trachylepis", "T. maculata", has five instead of three keels, 32 to 34 midbody scales, and separated parietal scales. "T. tschudii" agrees with the Noronha skink in size, coloration, numbers of scales, and discrete characters, such as having the supranasal, parietal, and prefrontal scales all in contact. The muzzle is narrow and long. The lower eyelid contains a large, transparent disk. The head is olive-brown. There are black scales with a white border between the eyes and the ears. The body is somewhat darker than the head and  covered with irregular black and white spots above and is bluish white below. The limbs are yellowish white below. The tail is light brown above, but has two rows of darker spots, and yellowish white below. Snout-to-vent length is 83 mm (3.3 in), head length 10 mm (0.39 in), head width 6.5 mm (0.26 in), length of the body 33 mm (1.3 in), length of the forelimb 15 mm (0.59 in), length of the hindlimb 23 mm (0.91 in), and length of the (incomplete) tail 40 mm (1.6 in).