Siagonodon Peters, 1881

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 : 17-19

Genus Siagonodon Peters, 1881

Typhlina Wagler, 1830: 196 . Type species: Acontias lineatus Reinwardt [Nomen nudum] and Typhlops sentemstriatus Schneider, 1801 , by monotypy; suppressed by ICZN, 1982, Opinion 1207.

Catadon A.-M.-C. Dumeril and Bibron, 1844: 318. Type species: Anguis septem-striatus Schneider, 1801 , by monotypy. [Preoccupied by Catadon Linnaeus, 1761 : Cetacea .]

Siagonodon Peters, 1881: 71 . Type species: Anguis septem-striatus Schneider, 1801 , by original description.

Diagnosis. Species of Siagonodon have 14 midbody scale rows, 10–14 midtail scale rows, 206–289 middorsal scale rows, 8–20 subcaudals, two supralabials, small or moderate or large anterior supralabials, 202–300 mm maximum adult total length, a body shape of 39–130 (total length/width), a relative tail length of 2.1–6.6%, a tail shape of 1.3–2.6, striped pattern, multiple dorsal colors, and white venter (Table 2). They also lack a supraocular scale. The absence of a supraocular scale distinguishes this genus from the other genus in the subtribe, Epictia (except E. nasalis ). Other traits distinguishing the two genera show overlap, but species of Siagonodon tend to have fewer midtail scale rows and a white venter (Table 2). Only one species of this genus was sequenced.

Content. Four species ( Table 1; Fig. 6).

Distribution. Siagonodon is distributed east of the Andes in South America, from southeastern Venezuela, Guyana, and French Guiana in the north to Argentina ( Fig. 8).

Etymology. The generic name is masculine and derived from the Greek nouns siagon (jaw) and odon (tooth), probably in allusion to the presence of teeth only on the lower jaw.

Remarks. Species placed here in Siagonodon include members of the septemstriatus Group (Orejas- Miranda 1967; Peters 1970). Only one representative ( S. septemstriatus ) was included, and it clustered with a monophyletic Epictia , as expected based on character data. However, future molecular studies with additional species are needed to further test the allocation of species to these two genera.