Trachylepis thomensis, Ceríaco, Luis M. P., Marques, Mariana P. & Bauer, Aaron M., 2016

Ceríaco, Luis M. P., Marques, Mariana P. & Bauer, Aaron M., 2016, A review of the genus Trachylepis (Sauria: Scincidae) from the Gulf of Guinea, with descriptions of two new species in the Trachylepis maculilabris (Gray, 1845) species complex, Zootaxa 4109 (3), pp. 284-314 : 291-296

Trachylepis thomensis sp. nov.

( Figs 3–4 )

Euprepes notabilis [non Euprepes notabilis Peters, 1879 ] ( Greef 1884: 48; Vieira 1887: 237; Bocage 1886a: 68, 1889: 34)

Lygodactylus [sic!] maculilabris ( Henriques 1917: 81)

Mabuia maculilabris (Gray) ( Bedriaga 1892a: 817, 1893b: 438; Bocage 1905: 92; Boulenger 1906: 205; Henriques 1917: 143)

Mabuya maculilabris, Gray ( Manaças 1958: 184, 1973: 223; Schätti & Loumont 1992: 29; Hofer 2002: 82; Jesus et al. 2005: 469; Rocha et al. 2010: 375)

Trachylepis cf. maculilabris - São Tomé (Ceríaco 2015: 512)

Holotype. MUHNAC /MB03-000712, adult male collected in the vicinity of Água-Izé (N: 0.12750, E: 6.64067; WGS-84), São Tomé Island, Republic of São Tomé & Príncipe, by Ruben Soares, Teresa Pité and Artur Serrano on 18 June 1984 ( Fig. 4 ).

Paratypes. All specimens from the Island of São Tomé, Republic of São Tomé and Príncipe. Twelve specimens: MUHNAC /MB03-000715 adult male collected in São Tomé city (N: 0.34058, E: 6.73753; WGS-84) by Ruben Soares, Teresa Pité and Artur Serrano on June 1984; MUHNAC /MB03-000716 (a–d) unsexed adults collected in Morro Peixe (N: 0.40536, E: 6.63876; WGS-84) by Ruben Soares, Teresa Pité and Artur Serrano on 17 June 1984; CAS 218819– 21 adult females collected in mouth of Água Anambo (N: 0.32572, E: 6.50839; WGS-84) by R.C. Drewes, R.E. Stoelting and J.V. Vindum on 3 April 2001; CAS 219287- 88 adult male and female collected in Praia Lagarto (N: 0.32970, E: 6.72904; WGS-84) by R.E. Stoelting and D.J. Long on 1 May 2001; MHNG 2461.81 and MHNG 2461.82, adults male and female collected in the surroundings of São Tomé city (N: 0.34058, E: 6.73753; WGS-84) by J. Haft and J. Fahr on July 1989.

Diagnosis. The new species is readily distinguished from all other Trachylepis by the following combination of characters: (1) medium and robust body size, up to at least 98.2 mm SVL; (2) colour pattern olive-brown dorsally, with black-and-white speckles, venter yellowish, thin stripe comprising approximately 7–8 white speckles from the back of the eye to the top of the tympanum, no distinct longitudinal or transverse dorsal bands; (3) MSR 31–35, SAD 54–60, SAV 58-64; (4) KDS 5 or 6; (5) scales on palm of hands and soles of feet smooth; (6) Supranasals always in contact, forming a suture, or at least in contact at a single point; and (7) yellow color on the scales around the outside of the tympanum.

Description of the holotype. Adult female in good condition but tail mutilated. Arrangement and relative size of head, body and tail scales typical for Trachylepis . Robust and cylindrical body with well-developed pentadactyl limbs. Fore- and hind-limbs overlap when adpressed against the body. SVL 82.3 mm, tail length 129.3 mm. Head length 16.2 mm, with relatively acuminate snout (HL 164.5% HW). Other relevant measurements are presented in Table 3 . Rostral as wide as high. Rostral visible from above, large nostrils set posteriorly so that postnasal effectively borders nostril. Supranasals in broad contact, frontonasal rounded anteriorly, wider than long, laterally in contact with loreal scale. Prefrontals hexagonal, separated by supranasals, in contact with the following head shields: frontonasal, loreal, first and second supraoculars, first supraciliary and frontal. Two loreals, the posterior and dorsal margins of the largest loreal border an enlarged preocular. Frontal length equal to distance between anterior tip of frontal and tip of snout; frontal in contact with three supraoculars. Frontoparietals two, in contact with each other, the frontal, third and fourth supraoculars, parietal and interparietal. Frontoparietal plus interparietal length is 1.3 times the length of the frontal. Interparietal with visible parietal foramen; parietals about three times larger than frontoparietals and contacting each other at the anterior point of the interparietal. Parietals in broad contact. A pair of large, broad nuchals collectively bordered by a total of nine dorsals. Supraciliaries six, second largest. Supralabials seven, the fifth being the subocular. Infralabials seven. The postmental borders seven scales. Transparent scale present in lower eyelid, as is usual for Trachylepis . Pre-temporals two. Tympanum visible, approximately the same height as eye. Dorsal scales with five to six keels. Ventral scales smooth. MSR 34, SAD 57, SAV 60. Limbs with five digits; scales on soles of hands and feet smooth. Relative length of fingers IV>III>II>V>I, relative length of toes IV>III>V>II>I. Finger-IV lamellae 15 (right side), Toe-IV lamellae 21 (right side). Tail long, robust and tapering smoothly. In preservative, background colour of flanks and upper side of head, neck, dorsum, legs and tail brown, with many distinctive dark-brown and/or white speckles starting at neck and running through entire dorsum to anterior half of tail. Stripe composed of 7–8 small, narrow white speckles starting at the posterior part of the eye, and ending above the ear. Supralabials greyish-white, superior part of labials bordered by a darker color. Venter uniformly pinkish-yellow, same as the palmar regions of hands and feet.

Variation. Variation in scalation and body measurements of the paratypes of T. thomensis are reported in Table 3 . The parietals are usually in broad (CAS 218819, 218821, 219287) or narrow contact (CAS 218820), with the exception of MUHNAC/MB03-000714 and CAS 219288 in which the parietals are separated. Supranasals are always in broad (MUHNAC/MB03-000714, 715, 716a–d) or narrow (CAS 218819, 218820, 218821, 219287, 219288) contact. Prefrontal contact is variable in the type series: MUHNAC/MB03-000716a, 716d, CAS 218819, 218820 and 218821 have the prefrontals in broad contact; in CAS 219288 prefontals are in narrow contact; in MUHNAC/MB03-000714, 715, 716b–c and CAS 219287 the prefrontals are separated. Prefrontals of MUHNAC/ MB03-716d in contact forming a suture. Head shields of the adult paratype MUHNAC/MB03-000715 exhibit several abnormalities: frontal longitudinally fragmented, parietals considerably diminished in length and not in contact, separated by the interparietal and nuchals. In MUHNAC/MB03-000714 and MUHNAC/MB03-000716c the frontal is large and rounded laterally and anteriorly. Parietals are separated by the anterior part of the interparietal. In MUHNAC/MB03-000716a the frontal is rounded at the sides and anteriorly. Colouration of the paratypes agrees with that of the holotype.

We also investigated variation in the Rolas population ( Table 4 ). The following specimens are not considered as paratypes given their geographical separation and unique haplotype according to Jesus et al. (2005b). Members of the Rolas population do not differ significantly in any morphological characters from the São Tomé population. Supranasals are always in broad contact and the prefrontals are always in narrow contact, but the dorsum is not clearly speckled, as in specimens from São Tomé.

Colouration. Colour in life: olive-grey background on flanks and upper side of head, neck, dorsum, legs and tail, with many distinctive dark-brown and/or white speckles starting at the neck and running along the entire dorsum to the anterior half of the tail. Stripe composed of 7–8 small and narrow white speckles starting in the superior part of the back of the eye and ending above the ear. The ear is bordered by a distinctive yellow colour. Supralabials greyish-white, superior part of labials bordered by a darker colour. Venter uniformly pinkish-yellow, same as the palmar regions of hands and feet.

Comparison with other Gulf of Guinea island species. Table 2 summarises the most important distinguishing characteristics between T. thomensis sp. nov. and all other Gulf of Guinea oceanic island Trachylepis . Comparisons between the newly-described species from São Tomé and Príncipe are given under the Príncipe species description. Comparing T. thomensis with T. maculilabris from West Africa, the new species has a greater SVL, greater head length, shorter tail, and higher numbers of lamellae under the fourth toe and fourth finger ( Table 2 ), and its colouration pattern is also considerably different, as it has black and white speckles on the dorsum, whereas T. maculilabris has only dark flecks. Trachylepis maculilabris has a very distinct white stripe starting on the labials and extending to the forelimb insertion that is completely absent in T. thomensis . In T. maculilabris the anterior four supralabials are usually brown, bearing one white spot, which is not common in T. thomensis , whose supralabials are usually greyish-white. Comparing T. thomensis with the recently-described T. adamastor , several characteristics differ considerably: T. thomensis has a smaller SVL, higher number of SAD, lower number of SAV, higher number of LUFT, the presence of two pretemporals (versus one in T. adamastor ), and its colouration differs considerably from T. adamastor : dark-brown with subtle white speckles dorsum and greyish venter. Comparing T. thomensis with the Annobon Island endemic T. ozorii , the new species has a lower number of supraciliaries, higher numbers of keels on the dorsal scales, lower numbers of scales around the midbody, lower numbers of paravertebral scales, and supranasals are always in contact in T. thomensis , but separated in T. ozorii ( Table 2 ). Colour patterns are also distinct in both species: T. thomensis has a brownish back with some dark and white speckles, and a yellowish venter; while T. ozorii has a brownish-bluish colouration on the dorsum, and is covered with small black speckles and a bluish-white venter. T. thomensis and T. affinis can be easily distinguished from one another by several morphological characters, but primarily by the presence versus absence of dorsolateral stripes, size, and acuminate snout. Trachylepis thomensis has a greater SVL, less bulky head, higher numbers of scales around the midbody, higher numbers of scales on the vent and on the dorsum, and more keels on the dorsal scales ( Table 2 ). Colouration is bold and contrasting, whereas T. thomensis lacks distinctive longitudinal stripes on the lateral sides of the body as in T. affinis .

Distribution. Endemic to São Tomé Island, Rolas Islet and Santana Islet, Republic of São Tomé & Príncipe, West Africa.

Habitat and natural history notes. This species is widely distributed throughout the island, although very few animals were seen above 100m or in dense forest. Most animals were observed basking near roads, rocks and slopes, and they are often seen in human settlements on pavements and in gardens of the capital city (L.C. pers. obs.; Fig. 3 ). Manaças (1958) mentioned that two females collected in October showed clear signs of sexual activity, one of the specimens having four fully-developed eggs (11 x 8 mm). Later, Manaças (1973) noted that all females collected in July and August had 4– 5 eggs, the smallest measuring 13 x 7 mm and the largest 19 x 9 mm. In an analysis of stomach contents, Manaças (1958) recorded the following dietary items: Tenebrionidae , Scarabeidae , Coleoptera (adults and larvae), Hymenoptera , Formicidae, Orthoptera, Diptera and Arachnidae.

Etymology. The specific epithet ' thomensis ' refers to the Island of São Tomé and is applied here as a substantive in apposition. We propose the English name of " São Tomé Skink" and the Portuguese name "Lagartixa de São Tomé ".

Figures

FIGURE 3. Trachylepis thomensis sp. nov. (specimen not collected), from São Tomé Island (Photo: Luis Ceríaco).

FIGURE 4. Holotype of Trachylepis thomensis sp. nov. (MUHNAC / MB 03 - 715) (Photo Luis Ceríaco).

Tables

TABLE 3. Measurements and scale cοunts οf the hοlοtype and paratypes οf Trachylepis thomensis sp. nov. Abbreviatiοns are the same as thοse described in Materials and Methοds.

Holotype MB03̶00 0 712 Sex ♂	MB03̶00 0 715 ♀	MB03̶00 0716a ♀	MB03̶00 0716b ♀	MB03̶00 0 961 ♀	MB03̶00 0 962 ♀	CAS 218819 ♀	CAS 218820 ♀	CAS 218821 ♀	CAS 219287 ♂	CAS 219288 ♀	MHNG 2461.81 ♂	MHNG 2461.82 ♀
SVL 82.3	74.0	87.8	80.7	77.6	80.1	74.3	76.0	87.9	85.6	74.5	91.5	92.1
TL 129.3	143.2	180	-	143.7	116.3	-	141	128	136	118	144.5	134.2
HW 9.8	11.4	11.0	10.9	12.1	12.0	9.7	10.1	11.8	12.0	9	13.5	12.0
HL 16.2	17.9	16.8	17.1	15.3	18.5	16.2	16.3	18.9	18.0	16.0	21	18.8
HH 7.8	11.1	9.1	8.0	6.3	9.2	7.8	7.2	10.2	9.5	7.6	11.1	9.1
IN 2.3	3.2	2.5	2.4	1.5	3.7	2.6	2.7	2.9	2.3	2.3	3.7	2.9
EN 4.0	6.2	5.5	4.0	3.9	4.4	4.6	5.0	6.0	5.3	4.4	5.9	4.7
ES 6.2	8.8	6.7	6.7	6.3	7.6	6.1	6.1	7.9	7.2	6.3	7.8	7.5
HL̸SV 19.6 L (%) ES̸HL 38.6 (%) HH̸HL 44.6 (%) HW̸HL 60.8 (%) TL̸SVL 157.1 (%) LUFT 15	24.2 49.3 62.0 64.0 193.5 15	19.2 39.9 53.9 65.6 205.1 15	21.1 39.6 50.0 63.9 - 15	19.8 41 41.3 78.9 185.1 20	23.1 41.1 49.5 62.0 145.2 -	21.8 37.5 48.1 59.7 - 16	21.5 37.6 44.2 61.6 185.4 16	21.5 42.0 53.9 62.4 145.6 15	21.0 39.8 52.8 67 158.8 16	21.3 39.5 47.7 56.6 158.7 16	23.0 37.1 52.6 64.2 157.9 20	20.4 39.9 48.2 64.1 145.7 17
LUFF 21	20	21	20	-	15	21	21	22	20	22	15	16
MSR 34	34	33	34	34	34	31	32	32	33	33	34	35
SAD 57	56	58	59	57	56	58	55	55	55	58	58	57
SAV 60	60	59	60	64	58	63	63	61	58	61	63	61
KDS 5-6	5	5	5	5-6	4-6	5-6	5-6	5-6	5-6	5-6	5	6

TABLE 4. Measurements and scale counts of Rolas Islet population of Trachylepis thomensis sp. nov. Abbreviations are the same as those described in Materials and Methods.

IICT 3-1954	IICT 4-1954	IICT 5-1954	IICT 6-1954	IICT 7-1954
Sex ♀	♂	♀	♂	♀
SVL 95.2	90.6	83.1	65.6	80.8
TL –	–	130	110	147.3
HW 13.3	11.8	10.1	9.1	10.9
HL 22.5	20.4	17.9	15.4	16.3
HH 11.2	10.9	7.8	7.1	8.3
IN 2.8	2.9	2.5	2.6	2.6
EN 6.2	6.6	5.0	4.4	4.7
ES 9.6	8.9	7.7	7.0	6.8
HL/SVL (%) 22.9	22.5	21.5	23.4	20.2
ES/HL (%) 42.8	43.7	42.8	45.5	41.9
HH/HL (%) 49.8	53.6	43.4	45.9	51.0
HW/HL (%) 59.3	58.0	56.2	59.3	66.6
TL/SVL (%) –	–	156.5	167.7	182.2
LUFToe 14	14	14	14	14
LUFFinger 16	16	16	16	16
MSR 34	33	34	32	33
SAD 54	56	54	–	53
SAV 61	59	58	62	60
KDS 5	5	6	5	5