Trachylepis adamastor, Ceríaco, Luis M. P., 2015

Ceríaco, Luis M. P., 2015, Lost in the middle of the sea, found in the back of the shelf: A new giant species of Trachylepis (Squamata: Scincidae) from Tinhosa Grande islet, Gulf of Guinea, Zootaxa 3973 (3), pp. 511-527 : 513-520

Trachylepis adamastor sp. nov.

( Figs. 2–4 )

Holotype. IICT nº2-1970, Adult female collected in the locality of "Pedras Tinhosas" (N: -1.34135556, E: - 7.29151389; WGS-84), Republic of São Tomé e Príncipe, by an unknown collector in 21th March 1970 ( Fig. 2 ).

Paratypes. Seven specimens: IICT nº1-1970, Adult male collected in the same locality of the holotype, also by an unknown collector in 1970, IICT nº1-1971, adult male, IICT nº2-1971, adult female, IICT nº3-1971, adult female, IICT nº4-1971, adult female, IICT nº5-1971, adult female, and IICT nº6-1971, both from the same locality of the holotype and collected by an unknown collector in 1971.

Diagnosis. A large and robust species of Trachylepis identified to the genus by the following combination of characters: four-limbed lizard, body covered with relatively large scales, dorsal and ventral scales polished, dorsal and ventral scales not highly differentiated (i.e. no great variation in size or structure), nostril well separated from the rostral shield, eyelids fully moveable and capable of closing the eye, lower eyelid with a large transparent disc, dorsal scales keeled, limbs pentadactyl and well developed, femoral pores absent. The new species can be easily distinguished from all other Trachylepis species by the following combination of characters: (1) large and robust body size, up to at least 112.0 mm SVL; (2) color pattern consisting of dark-brown dorsal coloration, with subtle black and white speckles, venter grayish; (3) MSR 31–34, SAD 49–54, SAV 63–66; (4) KDS 5 or 6; (5) scales on sole of feet and hands smooth; (6) one pretemporal scale; (7) very small ear opening.

Description of the holotype. Adult female in perfect shape but mutilated tail. Arrangement and relative size of head, body, and tail scales typical for Trachylepis . Robust and cylindrical body with robust legs. SVL 105.6 mm, TL 140 mm. HL 19.4 mm, with relatively acuminate snout (HL 153.5% HW). Other relevant measures are presented in Table 1 . Rostral as wide as high. Fore- and hind limbs easily touching each other when addressed against body. Rostral visible from above, nostrils set posteriorly so that postnasal effectively borders nostril, supranasals in small contact. Frontonasal almost hexagonal, wider than long, laterally in contact with loreal scale. Pair of quadrilateral prefrontals, forming median suture, in contact with frontonasal, loreal, first and second supraoculars, first supraciliary, and frontal. Frontal rhomboid, in contact with length of second SO. Frontoparietals two, each in contact with frontal, third and fourth supraoculars, parietal and interparietal. Supraciliaries five, second largest. Supralabials seven, fifth subocular. Infralabials six. Transparent scale present in lower eyelid, as usual for Trachylepis . Interparietal rhomboid, separated from nuchals by parietals; parietal eye small, almost invisible. Pretemporal one. Parietals in contact. Dorsal scales shiny, highly polished, most dorsal scales have five keels, the three central keels more pronounced than the outer. Ventral scales smooth. MSR 36, SAD 50, SAV 63. Limbs with five digits; scales on soles of hands and feet smooth, not keeled. Relative length of fingers II>III>IV>V>I, relative length of toes IV>III>V>II>I. Finger-IV lamellae 16 (right side), Toe-IV lamellae 18 (right side). Tail long, robust and tapers smoothly. In preservative, background color of flanks and upper side of head, neck, dorsum, legs and tail very dark-brown, with many subtle white speckles in dorsum starting in neck and running through entire dorsum to base of tail. Very subtle darker lateral band, starting in extremities of nuchals continues until arm insertion. Lateral area of body greyish, with some darker brown pigmentation. Venter uniformly yellowish-white. Supralabials present whitish area in the base, black in top.

Variation. Variation in scalation and body measurements of paratypes of T. adamastor are reported in Table 1 . All paratypes are in accordance with the holotype, in both measurements and scalation. All paratypes present parietal scales in contact and forming a suture, with exception of IICT 5-1971, in which parietals are in contact in a single point; frontoparietals in contact forming suture in all paratypes; supranasals always in contact forming suture, with exception of IICT 3-1971, in which supranasals are in contact in a single point; prefrontals in contact forming suture in three paratypes (IICT 2-1971, IICT 3-1971, IICT 5-1971) and in contact in single point in four specimen (IICT 1-1970, IICT 1-1971, IICT 4-1971, IICT 6-1971). Coloration generally agree with that of the holotype: paratypes IICT 1-1970, IICT 1-1971 and 2-1971 presents several pale white speckles in the dorsum, while in the remaining paratypes the dorsum is darker with less distinct (IICT 4-1971, IICT 6-1971) or totally absent speckles (IICT 3-1971, IICT 5-1971).

Coloration. Color in life varies from dark-grey on flanks and venter to almost black on upper side of head, neck, back, legs and tail, with subtle black and white speckles on dorsum ( Fig. 3 ). Venter, lower side of head, neck, lower side of limbs and tail grayish ( Fig. 3 ).

Comparison with other Gulf of Guinea oceanic island species. Table 2 summarizes the most important distinguishing characteristics between T. adamastor and all other Gulf of Guinea oceanic islands Trachylepis . Comparing T. adamastor with T. cf. maculilabris — Príncipe, the new species presents a considerably longer SVL, a lower TL/SVL ratio, a higher number of SAV, and a lower number of LUFT (Table 2). Also T. adamastor only have one pretemporal (two in T. cf. maculilabris — Príncipe), prefrontal scales in contact forming a suture (separated or in contact in just a single point in T. cf. maculilabris — Príncipe), and the very dark-brown and white-speckled dorsum and grayish ventrum coloration of T. adamastor contrasts with the uniformly brown dorsum and greenish ventrum of T. cf. maculilabris — Príncipe (Table 2). Comparing T. adamastor with T. cf. maculilabris — São Tomé, several other characteristic differ considerably, as T. adamastor higher SVL, lower number of SAD, higher number of SAV, lower number of LUFT, the presence of just on pretemporal (vs. two in T. cf. maculilabris — São Tomé), and it's coloration differs considerably from the olive-brown with black and white speckles dorsum and yellowish ventrum coloration of T. cf. maculilabris — São Tomé (Table 2). Comparing T. adamastor with T. affinis from Príncipe Island leaves no possible confusion. T. adamastor presents a much higher SVL, lower TL/SVL ratio, higher number of MSR, lower number of LUFT and LUFF, five KDS (vs. 3 to 4 in T. affinis ), only one pretemporal (vs. two in T. affinis ), prefrontal scales in contact forming a suture (always separated in T. affinis ), supranasals in contact forming a suture (in contact in just a single point in T. affinis ), and the coloration pattern is also considerably different, with T. affinis presenting a marked dorso-lateral white stripe, absent in T. adamastor (Table 2). Comparing T. adamastor with T. ozorii , the new species presents a higher SVL, lower TL/SVL ratio, lower SAD, LUFF and LUFT, only one pretemporal (vs. two in T. ozorii ), a higher number of KDS (5 in T. adamastor vs. 3 in T. ozorii ), and supranasals in contact forming a suture (always separated in T. ozorii ) (Table 2). The coloration pattern is also different between the two species (Table 2). Ecologically, the species differs considerably from all other Gulf of Guinea oceanic island species. Trachylepis adamastor is adapted to the harsh and non-vegetated environment of the Tinhosa Grande islet, while T. cf. maculilabris — Príncipe, T. cf. maculilabris — São Tomé, T. affinis , and T. ozorii mostly occur in areas with vegetation, sometimes even being arboreal ( Jesus et al. 2003; Ceríaco et al. personal observation). One character that differentiates the new species from the other São Tomé and Príncipe species is the size of the ear opening, which is very small in T. adamastor .

Comparing T. adamastor with T. maculilabris from West Africa, the new species presents a considerable larger SVL (96.1–112.0 vs. 48.1–85.9 mm in T. maculilabris ), a higher number of SAV (63–66 vs. 57–61 in T. maculilabris ) and only one pretemporal (vs. two in T. maculilabris ). The coloration pattern is also considerably different. Dorsolateral bands or lightly colored lines starting in the eye and reaching the forelimbs are completely absent in Trachylepis adamastor , but always present in T. maculilabris .

Distribution. As far as presently known, the species distribution is restricted to Tinhosa Grande Islet, Republic of São Tomé e Príncipe, West Africa ( Fig. 1 ).

TABLE 2. Most important distinguishing characteristics between Trachylepis adamastor sp. nov. and other Gulf of Guinea islands Trachylepis . See Materials and Methods for abbreviations.

T. adamastor sp. nov. T. cf. maculilabris — T. cf. maculilabris —São T. affinis T. ozorii

(n = 8) Príncipe (n = 10) Tomé (n = 33) (n = 11) (n = 14) Geographic Tinhosa Grande islet Príncipe Island São Tomé Island and Rolas Príncipe Island Annobón distribution islet

(mm) 96.06–112.04 58.48–88.27 60.32–98.18 39.92–71.14 73.38–85.99 Habitat and natural history notes. The habitat used by the species is the rocks and rock outcrops of the islet. The trophic ecology of the species is currently unknown. The habitat is almost deprived of any type of vegetation and very few invertebrates occur in the islet, although live specimens were observed eating the yolk of recently broken bird eggs (Nuno Barros & Simon Valle pers. comm.; Fig. 4 ). The population appears stable and reaching high densities (Nuno Barros & Simon Valle pers. comm.). The ecological relations between the newly-described species and the nesting birds is unknown, but trophic relationships can be suspected, namely the predation of arthropods associated with bird nests, as the case of other reptiles from small oceanic islands and atolls ( Ineich et al. 2009). The species appear to share the islet with another reptile, a still unidentified Hemidactylus sp. (Nuno Barros, António Monteiro pers. comm.).

Etymology. The specific epithet ' adamastor ' refers to the mythical giant inhabiting a rock "in the end of the sea" present in the Luis de Camões famous odyssey 'Os Lusíadas', and is applied here as a substantive in apposition. We propose the Portuguese common name Lagartixa-adamastor and the English common name of Adamastor Skink.

Figures

FIGURE 1. Geographical location of Tinhosas islets and aerial photo of Tinhosa Grande and Tinhosa pequena (Photo by Luis Ceríaco). Each colored region corresponds to the geographical distribution of different Trachylepis species. Brown areas: Nominotypic T. maculilabris and T. affinis; Green area: T. cf. maculilabris — Príncipe; Orange area: T. cf. maculilabris — São Tomé; Blue area: T. ozorii; Red area: Tinhosas population.

FIGURE 2. Holotype of Trachylepis adamastor sp. nov. (IICT nº 2 - 1970). Photo by Luis Ceríaco.

FIGURE 3. Live photo of Trachylepis adamastor sp. nov. (specimen not collected), from Tinhosa Grande. Photo by Ross Wanless.

FIGURE 4. Trachylepis adamastor sp. nov. feeding on a recently broken egg (specimen not collected). Photo by Ross Wanless.

Tables

TABLE 1. Measurements and scale counts of the holotype and paratypes of Trachylepis adamastor sp. nov. See Materials and Methods for abbreviations.

SVL	IICT 1–1970 108.45	IICT 2–1970 (Holotype) 105.06	IICT 1–1971 96.06	IICT 2–1971 103.71	IICT 3–1971 108.74	IICT 4–1971 IICT 5–1971 98.33 108.79	IICT 6–1971 112.04
TL	175.64	140.00	158.45	139.94	-	- -	-
HW	15.22	12.99	11.38	12.14	13.70	10.63 12.99	15.22
HL	22.37	19.94	17.48	17.77	19.57	18.28 19.45	21.46
HH	13.00	10.84	8.20	9.16	9.14	8.02 8.86	10.60
IN	3.53	3.29	2.72	3.00	3.41	2.50 3.40	3.44
EN	6.82	5.82	5.59	5.44	6.27	5.78 5.70	6.80
ES	9.61	8.19	7.17	7.81	7.88	7.74 8.27	8.42
HL/SVL (%)	20.63	18.98	18.20	17.13	18.00	18.59 17.88	19.15
ES/HL (%)	42.96	41.07	41.02	43.95	40.27	42.34 42.52	39.24
HH/HL (%)	58.11	54.36	46.91	51.55	46.70	43.87 45.55	49.39
HW/HL (%)	68.04	65.14	65.1	68.32	70.01	58.15 66.79	70.92
TL/SVL (%)	1.62	1.33	1.65	1.35	-	- -	-
LUFToe	18	18	17	18	19	19 19	20
LUFFinger	16	16	17	17	16	16 16	17
MSR	31	34	31	32	33	31 32	34
SAD	53	49	51	54	-	53 54	53
SAV	65	63	66	64	66	63 65	64
KDS	5–6	5	5	6	5	5 5	6