Brasilotyphlus guarantanus Maciel, Mott & Hoogmoed 2009

Brasilotyphlus guarantanus Maciel, Mott & Hoogmoed, 2009

Brasilotyphlus guarantanus Maciel et al., 2009: 19.

Diagnosis (from Maciel et al., 2009). Maximum known TL of 305 mm (UFMT 22383). PA 151–170; SG 0–2. One pair of anal papillae may be present on the vent disc. A weak vertical keel is present on the terminal part of the body of most specimens. Maxillary teeth may reach the level of the posterior border of choanae or extend posteriorly beyond them. Dermal scales present in posterior part of body only; scales starting between annulus 154 and 160.

Description. TL 47.2 to 76.1 times (56.9 ± 6.1; n = 41) BW. Head slightly narrower than body. Males have larger and longer heads than females (Maciel et al., 2009). Snout projecting distinctly beyond mouth. Third nuchal groove ventrally incomplete, second collar partially fused below with first primary body annulus; a dorsal transverse groove is present on each collar, shorter and less distinctly pronounced on the first. Body subcylindrical, slightly wider than deep. Width along body may vary slightly.

Primary annular grooves completely encircling the body, except for at most the three anterior annular grooves that are ventrally interrupted, and the grooves interrupted by the vent. SG present in three specimens with two incomplete secondary grooves (MPEG 22387; UFMT 5589, 6648). Vent transverse, sometimes slightly irregularly shaped. AD 10–13; generally about as many on the anterior as on the posterior edge of the vent (e.g. five anterior and six posterior in the holotype MPEG 22382). Paired anal papillae were found only in two of the 27 males analyzed in a sample of 48 specimens. Small terminal shield present; generally no annuli posterior to vent. Weak vertical keel may be present on terminal shield; (in 27 of the 48 type specimens). Dermal scales start between primary annuli 154 and 160; at most two rows of dermal scales per fold. PMT monocuspid, maximally 25, little variation in size, but posterior maxillary teeth slightly smaller, extending to the level of the posterior border of the choanae or posteriorly of them. Maximally 13 bicuspid PVT; teeth smaller than PMT. At most 14 bicuspid PT; smaller than PMT. A distinct diastema between PVT and PT series. DT monocuspid, maximally 21, approximately same size as PMT.

Color. In life, B. guarantanus is lavender and there are two patterns of body coloration. In one the body is dark lavender and gradually paler towards the head. In the other the body is entirely pale lavender. In preserved specimens color is grayish or brownish. The venter and the lateral surface are slightly paler than the dorsum along the entire body. The area surrounding the vent is less pigmented, as are the mandible and part of the head. A very thin longitudinal midventral line darker than the background appears in the posterior half of the body of some specimens.

Variation. For variation see Table 8.

Distribution. Brazil (northern state of Mato Grosso and southern Pará) (Fig. 11).