Tricheilostoma Jan, 1860

Adalsteinsson, Solny A., Branch, William R., Trape, Sébastien, Vitt, Laurie J. & Hedges, S. Blair, 2009, Molecular phylogeny, classification, and biogeography of snakes of the Family Leptotyphlopidae (Reptilia, Squamata), Zootaxa 2244, pp. 1-50 : 20-21

Genus Tricheilostoma Jan, 1860

Tricheilostoma Jan in Jan and Sordelli, 1860:7; 1861: 7; 1861: 190. Type species: Stenosoma macrolepis Peters, 1857 , by subsequent designation by Loveridge, 1957: 246.

Diagnosis. Species of Tricheilostoma have 14 midbody scale rows, 10 (12 rarely) midtail scale rows, 152–253 middorsal scale rows, 10–23 subcaudals, three supralabials, moderate anterior supralabials, 138–400 mm maximum adult total length, a body shape of 32–68 (total length/width), a relative tail length of 3.4–10.7 %, a tail shape of 2.0–4.4, no striped pattern, brown dorsal color, and brown venter (Table 2). They also have a small supraocular scale. They are distinguished from the other genus in this subtribe, Rena , by having a brown or pale brown (not white) venter, three supralabials (but also in Rena bressoni , R. dissecta , and R. myopica ), and in having a lower number (on average) of middorsal scales (Table 2). The support for this group was 100% BP and 100% PP for the four-gene tree ( Fig. 3); no sequences were included in the nine-gene tree ( Fig. 4).

Content. Nine species ( Table 1; Fig. 7).

Distribution. Tricheilostoma is distributed from lower Central America ( Panama) south through South America (exclusive of the high Andes) to southeastern Brazil ( Fig. 8).

Etymology. The generic name is neuter in gender and derived from the Greek adjective tri (three) and Greek nouns cheilos (lip) and stoma (mouth), in allusion to the presence of three supralabial scales.

Remarks. See comments above, in previous account, regarding the distinction of Rena and Tricheilostoma . We included three individuals of T. macrolepis in the molecular analyses; two from a locality in northern Brazil and a third from Guyana. The deep divergence between sequences from the two sample localities ( Fig. 3) indicates that they represent two species. It has already been suggested that this wideranging "species" comprises multiple species ( Orejas-Miranda 1967).

(A) Rena dulcis ( United States: Oklahoma; Beckham County, Packsaddle Wildlife Management Area); photograph by Buddy Brown. (B) Tricheilostoma koppesi ( Brazil: Tocantins: Parqu Estadual de Cantão); photograph by Laurie J. Vitt. (C) Tricheilostoma macrolepis ( Brazil: Pará: 101 km S Santarém); photograph by Laurie J. Vitt. (D) Mitophis asbolepis ( Dominican Republic: Barahona; 0.3 km S, 13.5 km E Canoa); photograph by S. Blair Hedges; (E) Mitophis leptepileptus ( Haiti: l'Ouest; Soliette); photograph by S. Blair Hedges. (F) Tetracheilostoma breuili (Saint Lucia: Maria Major Island); photograph by S. Blair Hedges.