Leposoma sinepollex, Rodrigues, Miguel Trefaut, Jr, Mauro Teixeira, Recoder, Renato Sousa, Vechio, Francisco Dal, Damasceno, Roberta & Pellegrino, Katia Cristina Machado, 2013

Rodrigues, Miguel Trefaut, Jr, Mauro Teixeira, Recoder, Renato Sousa, Vechio, Francisco Dal, Damasceno, Roberta & Pellegrino, Katia Cristina Machado, 2013, A new species of Leposoma (Squamata: Gymnophthalmidae) with four fingers from the Atlantic Forest central corridor in Bahia, Brazil, Zootaxa 3635 (4), pp. 459-475 : 462-470

Leposoma sinepollex sp. nov.

( Figs. 1 , 2 )

Holotype: MZUSP 102266 ( Fig. 1 ), an adult male from Estação Ecológica Estadual de Wenceslau Guimarães (13°34’43.60”S, 39°42’35.40”W, 500 m a.s.l., WGS84), municipality of Wenceslau Guimarães, state of Bahia, Brazil, collected by the authors on December 9th, 2011. Field number MTR 21979.

Paratypes: MZUSP 102265, 102267 and 102268 (13°34'43.00"S, 39°42'32.80"W, 480 m a.s.l., WGS84) a young female, a young male, and, an adult female collected respectively on December 14th, 11 th and, 17th 2011, field numbers MTR 21950, 22062 and 22063; MZUSP 102269 (13°34'42.80"S, 39°42'46.70"W, 550 m a.s.l., WGS84), an adult female collected on December 10th 2011, field number 22094; MZUSP 102270, a young male, collected on December 14th 2011, field number MTR 22247; MZUSP 102271 (13°34'42.68"S, 39°42'29.88"W, 495 m a.s.l., WGS84), an adult male collected on December 17th 2011, field number MTR 22287. All from Estação Ecológica Estadual de Wenceslau Guimarães, state of Bahia, Brazil, collected by the authors.

Etymology: The specific name derives from the Latin “ sine ” (absent) and “ pollex ” (thumb), being a reference to the lack of the first finger in this species.

Diagnosis: A Leposoma characterized by elongate dorsal and lanceolate ventral scales arranged in diagonal rows, frontonasal single and smooth, five supraoculars, absence of pollex, third toe as long as or longer than fourth, absence of striations in lower part of head, parietals longer than wide and as long as interparietal, 27–29 dorsals, 25–29 scales around body, 17–19 ventrals, 12–14 pores in the male (absent in females), 9–10 and 9–11 subdigital lamellae respectively under IV Finger and IV Toe, and strong sexual dichromatism. Comparative meristic characters among Leposoma species are presented in Table 1 .

Comparisons with other species: (data from species in comparisons given in parenthesis) Leposoma sinepollex sp. nov. is a member of the scincoides group, differing from all species in parietale group, by presenting elongate dorsals and lanceolate ventral scales arranged in diagonal rows (wider, shorter, and longitudinally arranged dorsal and ventral scales). It can be promptly distinguished from all congeners by the absence of a pollex (all five fingers present). It differs from L. annectans , L. baturitensis , L. scincoides and L. puk by the presence of five supraoculars (four). This condition with five supraoculars is apparently homologous in L. nanodactylus and L. sinepollex sp. nov. and due to a split of the scale corresponding to the first supraocular in the other species.

Additionally, Leposoma sinepollex sp. nov. differs from L. annectans by having a single internasal (divided), absence of an azygous scale between internasals (present), a smooth internasal (heavily striated), parietals as long as interparietal (shorter), a fourth toe as long as or shorter than third (longer), rostral and genials smooth (keeled) and in the color of adult males which are almost black dorsally and ventrally (mostly dark brown dorsally and cream ventrally). From Leposoma scincoides it differs by its smaller size, ranging between 26.4–34.4mm SVL (larger, about 28.5–44mm SVL), by having a single internasal (divided), by the absence of an azygous scale between internasals (occasionally present), a smooth internasal (heavily striated), a scute separating third pair of genials from infralabials (absent), a fourth toe as long as or shorter than third (much larger) and in color pattern (males and females are light brown dorsally and cream ventrally). From Leposoma puk it differs by being smaller, ranging between 26.8–34.4mm SVL (larger, about 38.0– 41.8mm SVL), by heaving most of head scales, except rostral and internasal, with irregular striations (all smooth), a scute separating third pair of genials from infralabials (absent), a fourth toe as long as or shorter than third (much longer) a wider than long frontonasal (as wide as long and longer than wide) and in color pattern (ventral parts of head and body have a conspicuous reticulate pattern of irregularly disposed black spots concentrated laterally, however never so intense and dark as in L. sinepollex sp. nov.) From L. baturitensis it differs by having a series of enlarged, longitudinally elongate, juxtaposed, keeled or striated scales following the third pair of genials (a pair of enlarged wider than long scales similar to an additional pair of genials), a scute separating third pair of genials from infralabials (absent) and a fourth toe as long as or shorter than third (much larger).

Leposoma sinepollex sp. nov. is closer to L. nanodactylus and besides the lack of the fourth toe it further differs from it by (1) third pair of genials separated from labials by an elongate scute (in contact), (2) fourth supraocular much enlarged (not enlarged), (3) scales of dorsal part of head, except rostral and internasal, mostly striated (slightly striated, almost smooth); although also very similar in color, the dark pigmentation pattern in L. sinepollex sp. nov. is more intense. Morphometrically, L. sinepollex sp. nov. differs from L. nanodactylus by its smaller body size, relatively shorter trunk, and relatively longer limbs ( Table 2 ). Despite the presence of allometric differences in relative limb length, both species do not differ in foot length which, allied to the distinct proportion between toes in L. sinepollex sp. nov., show that the species also presented a reduction in the fourth toe length.

Description of the holotype: ( Fig. 1 ) Rostral broad, wider than high, contacting first supralabial, nasal and frontonasal. Frontonasal single, wider than long, slightly biconcave posteriorly, contacting prefrontals, rostral, nasal, and loreal. Prefrontals as long as wide, in broad contact, left one slightly smaller; contacting frontonasal, loreal, first and second supraoculars and frontal. Frontal hexagonal, with slightly concave lateral margins; approximately twice as long as wide, contacting prefrontal, second to fourth supraoculars and indenting a pair of frontoparietals posteriorly. Frontoparietals pentagonal, larger than prefrontals, in broad contact and contacting frontal, fourth and fifth supraoculars, parietal and interparietal. Interparietal wider and as long as frontal, with almost parallel lateral margins, longer than wide; slightly wider posteriorly and reaching approximately the same level of parietals. Parietals irregularly hexagonal, longer than wide, as wide as interparietal. Supraoculars five; second the smallest, fourth the largest, as large as or larger than frontoparietal, third and fifth with the same approximate size and larger than the first. First supraocular longitudinally elongate, contacting first superciliary, loreal, prefrontal, and second and third supraoculars. Second supraocular almost granular, surrounded by first and third supraoculars, prefrontal, and frontal. First and second supraoculars correspond in position to the first supraocular of other species of Leposoma . Nasal pentagonal, above first supralabial, large, longer than wide, with the nostril in the center; ventral margin slightly rounded, dorsal margin straight. Loreal posterior to nasal, narrow, longer than wide, diagonally oriented, contacting frenocular ventraly. Frenocular as wide as long, contacting second supralabial and followed posteriorly by a series of six infraorbital elongate granules, first and sixth the largest. Six smooth supralabials, first longest, third and fourth bellow eye; sixth separated from the tympanum by two much smaller scales. Six superciliaries, first largest, larger than first supraocular, expanded on lateral surface of head; sixth the smallest. Eyelid with semitransparent palpebral disc formed by four scales, central ones larger. Temporal region covered with elongate, strongly keeled juxtaposed scales. Lateral surface of neck with conical and juxtaposed, sometimes keeled granules, smaller than temporal scales, arranged in irregularly transversal rows. Ear opening bordered by a series of very small, smooth, granules; tympanum distinct, subovoid. Dorsal head scales with a series of sharp and irregularly longitudinal striations, except on frontonasal and rostral which are smooth.

Mental broad, wider than long. Postmental single. First pair of genials smallest in broad contact at middline, second largest, in contact anteriorly, both in contact with infralabials. Third pair of genials intermediate in size, separated medially by a pair of elongate scutes and from the infralabials by a smaller squarish scute. Mental, postmental, genials, and infralabials smooth. Four enlarged infralabials followed by two small granules; fourth the largest. Scales immediately posterior and lateral to third pair of genials enlarged, larger than gulars, elongate, juxtaposed, mostly strongly keeled or striated. Gulars in eight transverse rows, lanceolate, imbricate, strongly keeled, increasing gradually in size posteriorly. Interbrachial region with 10 scales identical to ventrals. Collar fold indistinct.

Dorsal scales large, strongly keeled, mucronate, imbricate, in 27 regular transverse rows between interparietal and posterior level of hind limbs. Lateral scales larger at midbody but smaller than dorsals and ventrals, slightly imbricate to juxtaposed; much smaller, flat, smooth and juxtaposed near groin and grading to even smaller conic granules at arm level. Scales around midbody 27. Ventrals lanceolate, keeled, mucronate, imbricate, in 18 regular transverse and diagonal rows from interbrachials (included) to preanals. Posterior margin of the vent with five scales; central and paramedial scales the largest. Total pores (preanal plus femoral) 13 (4 preanal).

Scales of tail imbricate, keeled, in complete rings, more regular ventrally; dorsal and lateral tail scales more strongly keeled and wider than ventral scales near the base of tail, becoming gradually identical towards the extremity.

Limb scales keeled and imbricate, except on ventral surface of brachium an on posterior surface of thigh, which are dominate by subimbricate or juxtaposed granules. Palmar and plantar surfaces with small, conical, juxtaposed granules. Subdigital lamellae mostly double, 10 on Finger IV and 11 on Toe IV. Fingers and toes clawed, with the following relative sizes: II<V<II<IV and I<II=V<IV≤III, respectively.

Dorsal and lateral surfaces of head, body and tail dark brown to black with an inconspicuous lighter dorsolateral line, one scale wide, extending from the occipital region to base of tail. Flanks darker with a series of very small, irregular and scattered white dots extending paraventrally from lower part of head to first third of tail. Ventral parts of head, body and tail black, except in the gular area and along central part of venter which are cream with scattered dark brown to black spots. Limbs dark brown to black with scattered white doting similar to that of paraventral region.

Measurements of the holotype (in mm): SVL=28.2; LBL=11.7; HH=14.0; HW=4.5; HL=6.8; FL=4.2; TL=4.1; FTL=4.5; HUL=3.0; HAL=5.5; TAL=22.2+10.1 (regenerated).

Variation: the type series is fairly homogeneous, showing little variation in scale characteristics and number of femoral pores ( Table 1 ). Like the holotype, all other specimens have five supraoculars, being the two first the smallest, six supralabials, four enlarged infralabials followed by two much smaller scales, six superciliars, and five preanal scales. All males have two femoral pores at each side; they are absent in females. Females are larger than males with a maximum snout-vent length of 34.4 and 29.0mm, respectively.

Adult males have a color pattern identical to the holotype and sexual dimorphism in color is evident. In adult females, dorsal parts of head, body and tail are light brown with irregular dark brown and cream spotting. Flanks and lateral surface of head are lighter with scattered yellowish reticulation. A yellowish cream stripe one-scalewide runs ventrolaterally in the first third of tail, whereas the rest of tail is light brown. Ventral parts of body are creamily white with very slight brown reticulation which becomes dominant in posterior part of tail. In juveniles two dorsolateral light stripes one scale wide extend from posterior part of head to first third of tail, becoming inconspicuous towards extremity.

Distribution and natural history: Leposoma sinepollex sp. nov. was obtained only at EEEWG, a state protected mountainous area in the Atlantic Forest central corridor in the state of Bahia. Figure 3 shows the type locality in the context of the distribution of all other Atlantic Forest Leposoma . The region of EEEWG was all formerly covered by pristine Atlantic Forest but about 20 years ago parts of it were explored for timber and plantations. Nevertheless, a large part of it remained with pristine forest, particularly near to the streams. Nowadays most of the disturbed areas are recovering. Large trees reaching up to 50m high and more than a meter diameter with a large variety of epiphytes dominated the local habitat. Among the epiphytes, Bromeliaceae and Araceae of several sizes were particularly abundant. Leaf litter is dense and the understory open ( Fig. 4 ). Four specimens of Leposoma sinepollex sp. nov. were obtained in pitfall traps along with 10 of L. annectans , the only other species of Leposoma living in this area. Three additional specimens of L. sinepollex sp. nov. and nine of L. annectans were obtained after actively searching among the leaf-litter. The only other gymnophthalmid obtained in the area was Dryadosaura nordestina .

Molecular Phylogeny: phylogenetic analyses under both BI and ML criteria recovered identical topologies (- ln = 6773.220941 for the ML topology) showing a strongly supported sister relationship between L. sinepollex sp. nov. and L. nanodactylus (PP=1.0 and BP=100; Fig. 5 ). The inclusion of this new species to our previous data set for the Atlantic Forests Leposoma (Pellegrino et al. 2011) rendered now a well-supported (PP= 1.0 and BP=100) basal placement to L. baturitensis within the scincoides group. With regard to the remaining Atlantic Forests species, the topology and level of support for nodes herein presented ( Fig. 5 ) are almost identical as those previously recovered (see Fig. 2 in Pellegrino et al. [2011]). Uncorrected p distances calculated for ND4 sequences between specimens ranged from 12% ( L. scincoides - L. annectans ) to 24% ( L. scincoides - L. baturitensis ) (Table 3). Smaller distances were found for cyt b sequences which ranged from 9% ( L. scincoides - L. puk ) to 20% ( L. sinepollex sp. nov. - L. baturitensis - L. scincoides ; L. baturitensis – L. sp). Larger intraspecific distances were found among L. scincoides samples: up to 15% (ND4) and 13% (cyt b). Among the three specimens of L. sinepollex sp. nov available for this study, we did not detected any intraspecific variability in both gene regions analyzed herein.

Figures

FIGURE 1. Dorsal (A), ventral (B) and lateral (C) views of the head of the holotype of Leposoma sinepollex sp. nov. (MZUSP 102266). Scale bar = 3 mm.

FIGURE 2. Living specimen of Leposoma sinepollex sp. nov. (A) and its sister species, L. nanodactylus (B), and their hands (C) showing the absence of the first finger on L. sinepollex sp. nov. (above), and L. nanodactylus (below) all fingers, but reduced pollex.

FIGURE 3. Distributional records of Leposoma of the scincoides group. Detailed map show records of L. sinepollex sp. nov. and L. nanodactylus

FIGURE 4. Habitat of Leposoma sinepollex sp. nov.: (A) general view of the mountainous area at EEEWG and (B) a detailed view from inside the pristine forest where specimens were found.

FIGURE 5. Bayesian phylogenetic tree inferred from combined mtDNA (50 % majority-rule consensus). Numbers on branches correspond to Bayesian posterior probabilities values and bootstrap proportions (≥ 50 %), respectively. The bold red lines highlight Leposoma sinepollex sp. nov. and its sister taxon within the scincoides group.

Tables

TABLE 1. Comparison of most variable external morphological characters in species of the genus Leposoma: scales around body (SAB), number of dorsal and ventral scales, total number of pores in males, Finger IV and Toe IV infradigital lamellae.

Species	SAB	Dorsals	Ven t ral s	Pores	Finger IV	Toe IV
parietale group
L. caparensis	27 – 30	29–32	19–24	16	8–11	14–16
L. ferreirai	30 – 33	42–44	26–27	12	13–14	19–21
L. guianense	23 – 26	30–35	19–25	9–12	9–12	14–17
L. hexalepis	32 – 36	31–36	21–26	12–14	11–14	15–20
L. ioanna	21 – 22	28–30	20	?	12–15	17–20
L. osvaldoi	26 – 29	32–34	20–23	10–12	9–11	13–15
L. parietale	23 – 27	30–38	19–24	10–17	8–11	10–16
L. percarinatum	24 – 27	35–40	22–28	–	10–13	15–20
L. rugiceps	20 – 25	27–31	22–24	10	11–13	17–18
L. snethlageae	24 – 26	31–36	21–23	8–12	8–10	11–-14
L. southi	20 – 25	28–33	20–24	8	10	13
scincoides group
L. annectans	21–27	26–30	16–20	10–13	9–12	12–16
L. baturitensis	24–26	25–27	17–18	9–11	11–12	16–18
L. nanodactylus	27–32	31–34	16–20	10-11	7–9	10–12
L. puk	27–30	26–30	20–22	17–18	13–14	16–19
L. scincoides	25–30	29–36	17–23	14–20	9–15	14–20
L. sinepollex sp. nov.	25–29	27–29	17–19	12–14	9–10	9–11

TABLE 2. Variation in morphometric measurements of males and females of L. sinepollex sp. nov. and L. nanodactylus, its closest relative. Data (in mm) correspond to the average ± standard deviation, and minimum and maximum values in parentheses. Also is presented the results of analysis of variance (SVL) and covariance (remaining variables, SVL as covariate) between males of the two species. Variables abbreviations are explained in the text.

	L. sinepollex sp. nov.	L. nanodactylus	ANOVA/ANCOVA (males)
variables	female (N=3) male (N=7)	female (N=1) male (N=6)	F P
SVL	30.5 ±3.8 28.2 ±0.8 (26.8–34.4) (26.4–29.0)	32.3 31.7 ±2.6 (27.3–34.0)	13.34 <0.01
LBL	15.3 ±2.0 14.2 ±0.6 (13.4–17.3) (13.1–14.7)	17.6 16.8 ±1.2 (14.6–17.7)	16.77 <0.01
HH	2.6 ±0.2 (2.4–2.8) 2.6 ±0.1 (2.5–2.8)	2.6 2.9 ±0.3 (2.6–3.2)	0.91 0.36
HW	4.3 ±0.5 (3.9–4.8) 4.4 ±0.3 (3.8–4.7)	4.0 4.7 ±0.5 (4.0–5.2)	6.90 0.03
HL	6.7 ±0.7 (6.0–7.5) 6.7 ±0.3 (6.2–7.0)	6.2 7.0 ±0.5 (6.1–7.6)	15.94 <0.01
FL	4.2 ±0.4 (3.9–4.6) 4.2 ±0.2 (3.8–4.4)	3.9 4.2 ±0.5 (3.4–4.9)	37.93 <0.01
TL	4.1 ±0.4 (3.7-4.6) 4.1 ±0.2 (3.6–4.1)	3.7 4.0 ±0.4 (3.5–4.4)	27.97 <0.01
FTL	4.4 ±0.5 (4.1–5.0) 4.4 ±0.1 (4.1–4.5)	4.6 5.0 ±0.8 (4.2–6.0)	0.57 0.47
HUL	3.0 ±0.3 (2.7–3.3) 2.9 ±0.1 (2.8–3.0)	3.0 2.7 ±0.2 (2.5–3.0)	28.15 <0.01
HAL	5.4 ±0.4 (5.0–5.8) 5.4 ±0.2 (4.9–5.5)	4.9 5.0 ±0.3 (4.5–5.4)	39.29 <0.01
TAL*	36.45 37.26	- 56.6 ±12.6 (44.4–69.6)
TAL/SVL	1.21 1.41	- 1.79 (1.63–2.05)