Tetracheilostoma Jan, 1861

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 : 23-24

Genus Tetracheilostoma Jan, 1861

Eucephalus Fitzinger, 1843: 24 . Type species: Typhlops bilineatus Schlegel, 1839 , by original description [Preoccupied by Eucephalus Laporte, 1834 : Coleoptera ].

Tetracheilostoma Jan, 1861: 191 . Type species: Typhlops bilineatus Schlegel, 1839 , by monotypy.

Diagnosis. Species of Tetracheilostoma have 14 (rarely 16) midbody scale rows, 10–12 midtail scale rows, 170–192 middorsal scale rows, 12–15 subcaudals, four supralabials, moderate anterior supralabials, 104–113 mm maximum adult total length, a body shape of 31–54 (total length/width), a relative tail length of 5.1–7.0 %, a tail shape of 1.4–2.7, striped pattern (dull yellow stripes), dark brown dorsal color, and brown venter (Table 2). They are distinguished from the other genus in this subtribe, Mitophis , by having a low number of middorsal scales (170–192 versus 262–414), stouter body (31–54 versus 43–94), and a dark brown dorsum (not a pale brown or unpigmented dorsum). 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. Three described species ( Table 1; Fig. 7).

Distribution. Tetracheilostoma is distributed on the Lesser Antillean islands of Martinique, Saint Lucia, and Barbados ( Fig. 8).

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

Remarks. Two of the three species of Tetracheilostoma were recently described, including one from Barbados ( Tetracheilostoma carlae ) that is the smallest known snake ( Hedges 2008).