Trachylepis affinis Gray 1838

Trachylepis affinis (Gray, 1838)

Fig. 8–10

Tiliqua affinis Gray, 1838: 289

Euprepes cupreus Fischer 1886: 6

? Mabuya Raddonii Gray (Angel 1920: 197)

Mabuya blanlingii [sic] (Hallowell) (Manaças 1958: 185) Mabuya raddoni (Manaças 1958: 191; Hofer 2002: 88) Mabuya affinis (Hallermann 1998: 22; Jesus et al. 2005a: 467)

Trachylepis affinis (Gray, 1838) is a widespread species-complex distributed across all of western Africa, from Senégal to Angola (Trapé et al. 2012), and its taxonomic and nomenclatural history is convoluted. Hoogmoed (1974) stabilised the nomenclature of T. affinis but several authors have adopted different names when referring to Trachylepis affinis from São Tomé and Príncipe. Manaças (1958) referred to the existence of " Mabuya blanlingii (Hallowell) [sic]", which was used to refer to T. affinis for some time (see Hoogmoed 1974), on Príncipe based on three males and two females collected at Roça Esperança on 18 November 1954. Surprisingly, in the abstract of the same publication, Manaças used the name “ Mabuya raddoni ” to refer to the same specimens. Curiously, Manaças (1973) cited Bedriaga (1893a) and Bocage (1903) as having referred to the same species from São Tomé and Príncipe, although both cited only T. maculilabris for both islands. Angel (1920) cited four specimens of " Mabuia Raddonii Gray " (another name in the synonymy of affinis —see Hoogmoed 1974) from São Tomé, of which three lack the distinctive dark lateral band. The single confirmed record of T. affinis from São Tomé island is the one of Fischer (1886), based on the holotype of Euprepes cupreus collected by German surgeon Carl Weiss (?-?)The specimen (Figure 8) is presently in the collections of the ZMH (catalog number R04347, formely 234 (812)) and “is evidently a M. [= Trachylepis] affinis ” according to Hallermann (1998) and our own observations (see Figure 8 and Table 6).

Based on mtDNA sequence data Jesus et al. (2005a) showed that the Príncipe Island population of T. affinis is highly differentiated from some mainland populations. Based on their analyses, T. affinis from Príncipe showed a 15% genetic distance from the single specimen (from Guinea-Bissau) based on cytochrome b sequences (Jesus et al. 2005a). The lack of comparative material, and the complex nomenclatural and taxonomic history of the species, prevented Jesus et al. (2005a) from a more meaningful and detailed consideration of the taxonomic status of the Príncipe population. However, based on our molecular analysis, the Príncipe population clearly nests in the main T. affinis lineage, having a very low divergence from specimens from Cameroon, suggesting that T. affinis arrived on the island only recently. Morphologically, specimens from Príncipe Island agree (Table 6, Figures 9–10) with the general characteristics of the species described by Hoogmoed (1974) and Trape et al. (2012). The lack of historical or recent material from São Tomé prevents us from confirming that the São Tomé population still exists.

Trachylepis affinis from Príncipe (N= 13) are characterized as a small to medium-sized skinks (SVL 39.9–71.1 mm) with tail length approximately 1.5 times SVL. Wide and not very acuminate head (HW /HL 67,8%), approximately 22% of SVL. Prefrontals always separated. Supranasals in narrow contact. Supraciliaries usually 5, sometimes 6; 4 supralabials anterior to subocular; rectangularly enlarged subocular in direct contact with the lip and not reduced basally by the intrusion of adjacent supralabials. Midbody scales rows 27–29, paravertebral scales 47–51, with 3–4 keels on vertebral and dorsal scales. Lamellae beneath the fourth finger 15–16, beneath the fourth toe 18–20. Digital lamellae neither keeled nor spinose.

Back uniformly brownish and belly light bluish in preserved specimens, and bluish to green in live specimens, with a white stripe on the lower part of the flanks; infralabials bluish and supralabials bluish at the base but brown higher up, mental pale blue; absence of distinct longitudinal stripes or transverse dorsal bands. Color in life olivebrown dorsally, with dark flecks. Two dark dorsolateral bands, followed by dark brown lateral colouration. A whitish ventral-lateral band separates the flanks from the venter. Scales of the venter cream or white, without markings.

Distribution. The species occurs on Príncipe Island and Bioko Island, and is also widely distributed in West and Central Africa (Trapé et al. 2012).

Habitat and natural history notes. Very little data are available about the habitat and natural history of T. affinis on Príncipe, where it is less abundant than T. principensis. During recent fieldwork on Príncipe only one specimen was spotted basking in the sun, together with a specimen of T. principensis. According to Manaças (1958) the stomach contents of Príncipe specimens contained Formicidae, coleopteran larvae, other unidentified insects, and Arachnidae.