Trachylepis (Xystrolepis) punctata Tschudi, 1845

Miralles, Aurélien, Chaparro, Juan Carlos & Harvey, Michael B., 2009, Three rare and enigmatic South American skinks, Zootaxa 2012, pp. 47-68 : 57-58

Status of Trachylepis (Xystrolepis) punctata Tschudi, 1845

In 1845, Tschudi described Trachylepis (Xystrolepis) punctata from the “ Waldregion ” (= Amazonia) of Peru. Although Roux (1907) later redescribed the holotype and only known specimen, this species has remained enigmatic. Based on its morphology, some authors considered it to be synonymous with Trachylepis atlantica (e.g., Travassos, 1946), whereas, based on the type locality, others (e.g., Peters & Donoso-Barros, 1970) concluded that it must be synonymous with one of the Amazonian Mabuya . In his “ Notes on American Mabuyas, ” Dunn (1936: 557) remarked that he was “unable to say what it is.” Peters and Donoso-Barros (1970) added Tschudi’s species to the unwieldy synonymy of M. mabouya mabouya (Lacépède) where it has remained until the present day. In this section, we consider the generic allocation of Tschudi’s species, correct its secondary homonymy, and propose some possible explanations for its provenance.

During this study, we examined recent photographs of the holotype and only known specimen of Trachylepis punctata . The holotype (MHNN 91.2426) is housed in the Museum of Neuchâtel in Switzerland and is in very poor condition. This specimen cannot be assigned to the genus Mabuya , because it has 5/5 auricular lobules, tricarinate dorsal scales in 39 rows at midbody, and the third supraocular in contact with the frontal. Species of Mabuya lack auricular lobules and have smooth to finely striated scales in 24–34 rows at midbody ( Table 4 ). Among Mabuya , the second (in M. agilis , M. agmosticha , M. altamazonica , M. berengerae , M. bistriata , M. carvalhoi , M. croizati , M. falconensis , M. frenata , M. guaporicola , M. lineolata , M. luciae , M. macleani , M. macrorhyncha , M. meridensis , M. nigropalmata , M. nigropunctata , M. pergravis , M. sloanii , and M. unimarginata ) or, rarely, the first (in species having the first and second supraoculars fused into a single scale, such as M. cochabambae , M. dorsivittata , and M. mabouya ) supraocular contacts the frontal ( Greer and Broadley, 2000; personal observation, Fig. 6 ). These characteristics of T. punctata are common among species of the Afro-Malagasy radiation ( Hoogmoed 1974; Mausfeld et al., 2002), now comprised of the genera Trachylepis and Chioninia , and we here formally recognize Tschudi’s species as a member of Trachylepis .

In 1845, three different species of Trachylepis had been assigned the same specific epithet. Andersson (1900) first noted the homonymy between Tiliqua punctata Gray and Lacerta punctata Linnaeus [currently considered a junior synonym of Trachylepis homalocephala (Wiegmann) from the Cape province, South Africa] and Schmidt (1945) proposed the replacement name Mabuya atlantica for Gray’s species (see Mausfeld and Vrcibradic, 2002, for a recent discussion of the nomenclature of the skink on Fernando de Noronha, Brazil). However, the homonymy of Tschudi’s name has never been corrected. In accordance with articles 52 and 60 of the Code ( ICZN, 1999), we propose Trachylepis tschudii new name as a replacement for Trachylepis (Xystrolepis) punctata Tschudi. The new name is a patronym for Dr. J. J. von Tschudi, who originally described this species.

Because of the poor state of the holotype, it may be impossible to unequivocally assign it to an existing species of Trachylepis . However, the specimen’s supposed origin in the Peruvian Amazon is difficult to believe, considering that the upper Amazon is so far from the Brazilian coast and no additional specimens of any Trachylepis have ever been collected in Amazonia. Three mutually exclusive hypotheses may explain the provenance of the specimen:

(1) Trachylepis tschudii is actually a very rare Amazonian species. Skinks from this genus have certainly crossed the Atlantic before ( Carranza & Arnold 2003; Mausfeld et al. 2002) as demonstrated by the presence of T. atlantica on Fernando do Noronha, Brazil, and T. tschudii may have dispersed across Amazonia in a manner similar to another African lizard, Hemidactylus mabouia ( Kluge, 1969; Powell et al., 1998).

(2) Trachylepis tschudii actually occurs somewhere in the Old World and the holotype was mislabeled.

(3) As proposed by Travassos (1946), Trachylepis tschudii is a junior synonym of T. atlantica . Assuming the specimen was mislabeled, the holotype actually would have been collected on Fernando de Noronha Island, Brazil. Or, if the holotype was actually collected in the Peruvian Amazon, the skinks from Fernando de Noronha have dispersed into Amazonia, again, similar to Hemidactylus mabouia .

We suspect that the third hypothesis is correct. Like Trachylepis atlantica , T. tschudii has the supernasals, prefrontals, and parietals in contact. Its body dimensions (SVL 83 mm, tail incomplete, head length 10 mm, head width 6.5 mm, according to Roux 1907), coloration, and scale counts all fall within the variation for this species (Mausfeld and Vrcibradic, 2002; Travassos, 1946). Tschudi’s skink is unlikely to be a specimen of T. maculata (characteristics in parentheses), because it has three keels on its dorsals (five), 39 scales at midbody

Figures

FIGURE 6. Cephalic morphology of Mabuya sensu lato, showing diagnostic features of supraocular and frontal contact in M. bistriata (a, MPEG 14561), M. mabouya (b, Holotype MNHN 5421), Eutropis multifasciata (c, representing the Asian clade, redrawn from Boulenger 1890: 181), Trachylepis tschudii (d, Holotype MHNN 91.2426) and T. maculata (e, NHM 1946.8. 18.6, and f, lectotype, MNHN 2932, redrawn from Bocourt 1879), T. atlantica (g, MNR 1175, redrawn from Travassos, 1946: plate III, fig. 5), Trachylepis quinquetaeniata (h, RMNH 17427 b, redrawn from Hoogmoed, 1974: 48), and Chioninia stangeri (i, syntype NHM 1946.8.2). Numbered scales are the most posterior supraoculars contacting the frontal (F) and frontoparietals (FP).