Trilepida affinis ( Boulenger, 1884 )

Pinto, Roberta R. & Fernandes, Ronaldo, 2017, Morphological variation of Trilepida macrolepis (Peters 1857), with reappraisal of the taxonomic status of Rena affinis (Boulenger 1884) (Serpentes: Leptotyphlopidae: Epictinae), Zootaxa 4244 (2), pp. 246-260 : 249-251

Trilepida affinis ( Boulenger, 1884)

Fig. 1

Stenostoma affine Boulenger 1884:396 .

Glauconia affinis — Boulenger 1893:62.

Leptotyphlops affinis — McDiarmid, Campbell & Tour 1999:19. Leptotyphlops affinis — La Marca & Soriano 2004:136.

Rena affinis — Adalsteinsson, Branch, Trape, Vitt & Hedges 2009:10 Trilepida affinis —Nattera-Mummak, González & Fernández 2015: 296 -297.

Holotype. Adult male ( Fig. 1 ), BMNH 75.2 .26.4 (now BMNH 1946.1.11.16), from state of Tachira in Venezuela, without specific locality data.

Diagnosis. Trilepida affinis can be distinguished from all other congeners by the following combination of characters: (1) snout truncate in dorsal and ventral views, and rounded in lateral view; (2) supraocular present; (3) rostral subtriangular in dorsal view, not reaching the anterior limit of ocular scales; (4) rostral shorter than supranasals; (5) frontal scale longer than other middorsal cephalic shields; (6) frontal longer than supraocular scale; (7) two supralabials (1+1); (8) four infralabials; (9) scales at midtail 10; (10) fused caudals present; (11) middorsals 214; (12) midventrals 202; (13) subcaudals 18; and (14) seven dorsal scales rows brown, contrasting with seven ventral rows cream, and head slightly lighter in dorsal view than body pattern.

Comparisons. Trilepida affinis differs from T. brasiliensis by having supraocular scales (vs. absent); differs from T. guayaguilensis , T. joshuai , T. macrolepis (rarely), and T. pastusa by having ten scales rows on midtail (vs. 12); differs from T. anthracina , T. dugandi , T. fuliginosa , T. koppesi , T. macrolepis , and T. salgueiroi by having two supralabials (vs. three); differs T. nicefori by having four infralabials (vs. three); differs from T. dimidiata by having snout truncate in dorsal and ventral views (vs. rounded); differs from T. brevissima by having snout rounded on lateral view (vs. obtuse-rounded); differs from T. jani by having frontal scale longer than other middorsal cephalic shields (vs. with similar size). Refers to Table 1 for additional meristic and color differences between congeners.

Redescription of the holotype ( Fig. 1 ). Adult male, TL 218 mm, TAL 24 mm; MB 3.9 mm; MT 3.5 mm; TL/ TAL 9.1; TL/MB 55.9; TAL/MT 6.9; HL 5.3 mm; HW 2.8 mm; eye diameter 3.4 mm. Body subcylindrical and robust; head subcylindrical slightly distinct from body, almost twice longer than wide. Snout slightly truncate in dorsal and ventral views, and rounded in lateral view; rostral subtriangular in dorsal view, not reaching an imaginary transverse line between anterior border of ocular; rostral contacting supranasal and infranasal laterally and frontal dorsally; nasal completely divided horizontally by oblique suture crossing nostril; nostril elliptical, obliquely oriented and placed in the middle of nasal suture; supranasal as high as long, bordering rostral anteriorly, infranasal ventrally, first supralabial and ocular posteriorly, and frontal dorsally; supranasal base longer as upper border of infranasal scale; upper lip composed by rostral, infranasal, anterior supralabial, ocular and posterior supralabial (1+1); temporal scale distinct from lateral dorsal scales; first supralabial crossing nostril and reaching eye level; first supralabial on the right side divided; second supralabial trapezoidal, reaching nostril level, lower than first supralabial and in broad contact with temporal scale posteriorly; ocular enlarged, subhexagonal with straight apex, slightly rounded at eye level, as high as long, contacting posterior borders of supranasal and first supralabial anteriorly, parietal and second supralabial posteriorly, and supraocular dorsally; eyes distinct (0.5 mm), placed centrally of expanded upper part of ocular shield, displaced above the level of nostril; supraocular as long as wide, smaller than frontal, contacting supranasal anteriorly, frontal, postfrontal and ocular laterally, and parietal posteriorly; middorsal cephalic shields (postfrontal and interparietal) subequal, hexagonal in dorsal view, weakly imbricate, as long as wide; frontal enlarged, longer than wide, longer than other middorsal, contacting rostral and supranasal anteriorly, supraocular laterally and postfrontal posteriorly; postfrontal as wide as long, contacting frontal and supraoculars anteriorly, parietals laterally and interparietal posteriorly; interparietal as wide as long, contacting postfrontal and parietals anteriorly, occipitals laterally and interoccipital posteriorly; interocciptal shorter than other middorsal, nearly twice wider than long, contacting interparietal and occipitals anteriorly, dorsal scales laterally and first middorsal scale posteriorly; parietal and occipital subequal in shape, irregularly pentagonal; parietal almost twice wider than long, lower margin contacting upper border of second supralabial, posterior margin contacting temporal, occipital and interparietal, anterior border in broad contact with ocular and supraocular and postfrontal laterally; occipital shorter than parietal, wider than long, its lower limit not reaching the level of upper margin of second supralabial; occipital separated of second supralabial by temporal; symphysial slightly cycloid, anterior and posterior borders respectively straight and slightly convex, as long as wide; four infralabials behind symphysial on both sides; first two infralabials subequal, nearly longer than wide; third infralabial slightly wider than first two; fourth infralabial distinctively longer than others. Middorsal scales 214; midventral scales 202; scale rows around midbody 14, reducing to 10 rows in the middle of the tail; cloacal shield enlarged and subtriangular; subcaudals 18; fused caudals present; terminal spine large and conical. Dorsal scales homogeneous, cycloid, smooth, weekly imbricate, and nearly two times wider than long.

Coloration in preservative. Body color pattern with seven dorsal scale rows brown and seven cream ventral scale rows; coloration of the head is slightly lighter than body dorsally; head color pale brown until lower limits of supralabials and first middorsal scale; lower limits of supralabials and infralabials cream; cloacal shield and terminal spine brown.

Geographic distribution. The species is known to date only from its holotype, which does not have a specific location of collection ( Fig. 2 ). Although MPL 0 1 and other specimens mentioned in literature suggest that Trilepida affinis may occurs along the Merida Mountain Range, all these records need for confirmation on the basis of detailed examination of voucher specimens.

Figures

FIGURE 1. Dorsal (A), lateral (B), and ventral (C) views of the head of Trilepida affinis holotype (BMNH 75.2.26.4). The arrow shows the divided base of first supralabial scale. Scale = 5 mm. Photos by R. Fernandes (MNRJ).

FIGURE 2. Geographic distribution of Trilepida affinis (grid) and Trilepida macrolepis (circles). Type locality is represented by open symbol, examined specimens by close symbol and literature records by triangles.