Apostolepis gaboi Rodrigues 1992

Guedes, Thaís B., Barbo, Fausto E., França, Daniella & Zaher, Hussam, 2018, Morphological variation of the rare psammophilous species Apostolepis gaboi (Serpentes, Dipsadidae, Elapomorphini), Zootaxa 4418 (5), pp. 469-480 : 470-474

Redescription of the holotype of Apostolepis gaboi Rodrigues 1992

( Figs. 1–2 , Table 1).

Described based on a single specimen (MZUSP 10290) from Queimadas (10° 23’ S, 42° 30’ W; 295 m a.s.l.), municipality of PilÃo Arcado, state of Bahia, Brazil. A slim juvenile female 215 mm SVL, 20 mm TL (8.5% of total length); body diameter 2.5 mm (1.2% SVL); head length 5.64 mm (2.4% SVL), head width 2.26 mm at broadest point (40.1% head length); head not distinct from neck; dorsal scales rows 15/15/15; ventrals 229, divided cloacal plate; paired subcaudals 31; rostral plate slightly wider (0.84 mm) than long (0.66 mm), visible in dorsal view; prefrontals large, slightly wider (0.98 mm) than long (0.89 mm), in broad median contact, shorter than frontal scale; frontal longer (1.31 mm) than wide (1.01 mm), anteriorly exceeding anterior border of supraoculars; parietals very long (2.77 mm), almost two times longer than frontal scale; parietal laterally contacting 5th and 6th supralabials, in contact anteriorly with frontal, supraocular and postocular, posteriorly with first rows of dorsals slightly increased; supraoculars smaller than frontal, with their anterior margin very straight; nasal plate entire, longer than high, thinner posteriorly, in contact with rostral, prefrontal, 1st and 2nd supralabials; nostril centralized in nasal plate; preocular one, very small; postocular one; supralabials six, 2nd and 3rd contact the eye, 5th and 6th increased in length; temporal scales indistinct, parietal in contact with 5th and 6th supralabials; mental triangular, as long as high, separated from chinshields by first pair of infralabials; chinshields in two pairs, second being longer (1.05 mm) than first (0.68 mm); first pair of chinshields in contact with first four infralabials, second pair with 4th and 5th infralabials.

Coloration of holotype faded after preservation in 70% ethanol. Head dark brown, except for the snout light cream; one cream blotch extending from 3rd to 5th supralabial scales; nostrils cream ( Fig. 1A ); neck with complete white collar (three scales long) in dorsal and lateral views followed by dark brown collar (two to three scales long); gular region cream anteriorly with incomplete dark brown band after chinshields ( Fig. 1A ); dorsum of body pale brown or beige with five narrow longitudinal brown stripes (one vertebral and four dorsolateral lines on the 4th and 6th rows) extending until the tip of the tail ( Fig. 1B and E ); ventral surface of body immaculate cream from the neck to subcaudals, except for the tip of the tail ( Fig. 1C ); tip of the tail dark brown in dorsal (12 scales long) and ventral (11 scales long) views; terminal spine dark brown ( Fig. 1D ).

Pictures of Apostolepis gaboi in life ( Fig. 2 ), show it has dorsum of the head dark brown; snout pale brown; distinct oval blotch pale brown covering the 3rd to 5th supralabials; nuchal collar white, followed by dark brown to black cervical collar; five black stripes arising in the black collar following to up the tail; vertebral and paraventral stripes are narrowest while paravertebrals are widest; dorsal background is rust-colored; tip of the tail is black and terminal spine is also black.

Intraspecific variation in continuous characters ( Table 1). Largest female 517 mm total length (TL), 31 mm of tail length; largest male has 424 mm and 38 mm. Total length 236–517 mm (mean = 349.3 ± 95.95 mm; n = 15) in females, 234–424 mm (mean = 299.7 ± 37.08 mm; n = 20) in males. Tail length 18–35 mm (mean = 25.33 ± 5.44 mm; 12.13–21.25% TL) in females, 16–40 mm (mean = 29.3 ± 5.52 mm; 7.63–18.50% TL) in males; ventral scales 200–239 (mean = 221.6 ± 11.32) in females, 190–230 (mean = 208.7 ± 9.18) in males; subcaudals 27–34 (mean = 30.95 ± 4.2) in males, 24–31 (mean =27.4 ± 2.35) in females. We found a significant secondary sexual dimorphism in the number of ventrals (H = 9.21; p <0.001; n = 35) and subcaudals (H = 16.07, p <0.001; n = 35); supralabials six (2nd and 3rd contacting the eye). Preocular absent (n = 9), 1/1 (n = 23) or 1/0 (n = 2). Preocular usually fused to prefrontals, except for the MZUFBA 1693 where it seems to be fused with the 2nd supralabial. Second pair of chinshields contacting 4–5 infralabials, except for the MZUFBA 1697 in which the first pair of chinshields contact first three infralabials and the secondary chinshields 3–4 infralabials.

Intraspecific variation in coloration. White nuchal collar cover two (MZUFBA 1674, 1676, 1680–81, 1685, 1689, 1694, 1702–03) to five scales long (MZUFBA 1673, 1680, 1690, and 1697), most specimens with three scales long (MZUFBA 1675, 1677–79, 1682, 1684, 1686–88, 1691–93, 1695–96, 1698–1701, 1704) ( Fig. 2A ); dark brown collar one and half (MZUFBA 1690, 1693, 1703) to three scales long (MZUFBA 1673–76, 1678, 1680–81, 1683–85, 1687, 1691, 1694, 1699) ( Fig. 3A ), contacting ventrals or starts on third dorsal scale row ( Fig. 3B ); dorsal coloration usually with vertebral stripe and two dorsolateral stripes each; dorsal stripes continuous, dark brown, speckled with small dots and arranged between the 4th and 5th dorsal rows ( Fig. 3C and D ); eight individuals with five stripes along the body (MZUFBA 1675, 1678, 1683, 1688, 1692, 1696–97, 1701, and 1703) and 12 with five stripes plus a pair of faint dashed brownish lines at the level of the 3rd dorsal row (MZUFBA 1679, 1689, 1691, 1695, and 1700); six specimens presented vestigial additional stripes (MZUFBA 1673, 1677, 1682, 1684, 1694, 1699, and 1702) ( Fig. 3C and D ); tail tip surrounded by dark brown band, including terminal spine; caudal band varies in its extent, covering ventral region of two (MZUFBA 1704), four (MZUFBA 1687, 1689, and 1696), five (MZUFBA 1679), six (MZUFBA 1982), seven (MZUFBA 1684) or eight subcaudals (MZUFBA 1695) ( Fig. 3E ).

Hemipenial morphology. Organ of adult specimen (MZUFBA 1683) fully everted and maximally expanded ( Fig. 4 ); hemipenis short, stout and unilobed, unicaliculate and unicapitate; lobe extends for about one third of the hemipenis; capitulum restricted to sulcate and lateral surfaces of the organ, covering half of the organ’s length at the level of the sulcus spermaticus; capitulum formed by small papillate calyces disposed concentrically on sulcate and lateral surfaces of the lobe, except for two outermost rows of calyces that are clearly larger in size and spinulate; on asulcate surface, lobes ornamented with two parallel rows of three to four deep, mediolaterally enlarged and papillate body calyces; body of hemipenis covered by spinules on sulcate surface and proximal region of asulcate surface; spinules reduce in number and increase gradually in size towards lateral surface and distal region of asulcate surface of the body, where they form one outer and distal row of greatly enlarged spines; the enlarged spines disposed asymmetrically on each side of asulcate or lateral surfaces; distally to the last row of enlarged lateral spines, hemipenial body is completely nude, except for a median row of spinules arranged along midline of asulcate surface; sulcus spermaticus forks within the base of the capitulum where it continues in almost parallel portions to reach distal surface of lobe on its sulcate side.

Distribution and natural history notes. Apostolepis gaboi is a psammophilous species endemic of the Caatinga ecoregion ( Rodrigues 1992, 2003; Guedes et al. 2014) with a restricted distribution known to encompass only the municipalities of Barra and PilÃo Arcado, in the eastern sandy bank of the SÃo Francisco River, state of Bahia, Brazil ( Fig. 5 ). The vegetation of the area is bushy and herbaceous Caatinga that grows on sandy soil and dunes ( Rodrigues 1992; Guedes et al. 2014). Apostolepis gaboi is both diurnal and nocturnal ( Rodrigues 1992; Guedes et al. 2014), with a probable feeding preference for elongated preys, as suggested by the only prey item registered so far and identified as Amphisbaena hastata (Damasceno 2002) .

Figures

FIGURE 1. Head views (left, right, dorsal and ventral, respectively) (A), dorsal (B) and ventral body views (C), tail views (dorsal and ventral, respectively), and dorsal midbody view (E) of the holotype of Apostolepis gaboi (MZUSP 10290) from Queimadas, municipality of Pilão Arcado, state of Bahia, Brazil.

FIGURE 2. General view of the holotypeof Apostolepis gaboi (MZUSP 10290) in life from Queimadas, municipality of Pilão Arcado, state of Bahia, Brazil.Photo by Miguel Rodrigues.

FIGURE 3. Color pattern variation of the preserved specimens of Apostolepis gaboi. Dorsal (A) and lateral (B) views of the head, lateral (C) and dorsal (D) views of the midbody, and ventral view of the tail(E).

FIGURE 4. Sulcate (left), asulcate (center), and lateral (right) viewsof thefully evertedand maximally expanded hemipenisof Apostolepis gaboi (MZUFBA 1683).

FIGURE 5. Landscape view from the Quaternary sandy dunes in the São Francisco River, state of Bahia, northeastern Brazil (A) and the map showing the distribution of Apostolepis gaboi in the left side of the São Francisco River (B). Photo A by Miguel Rodrigues.