Haitiophis Hedges & Vidal

Hedges, Blair, Couloux, Arnaud & Vidal, Nicolas, 2009, Molecular phylogeny, classification, and biogeography of West Indian racer snakes of the Tribe Alsophiini (Squamata, Dipsadidae, Xenodontinae), Zootaxa 2067, pp. 1-28 : 17

Genus Haitiophis Hedges & Vidal , New Genus

Type species. Zamenis anomalus Peters, 1863:282 .

Diagnosis. The single species in this genus has 21 midbody scale rows, 207–215 ventrals, 113–130 subcaudals, 2 apical scale pits, 8 upper labials, 10 lower labials, 14 total maxillary teeth, and 18–19 dentary teeth ( Table 2). Haitiophis differs from all other genera except Alsophis in its high number (21) of midbody scales, and from Alsophis in its low number of total maxillary teeth (14 versus 18–21) and dentary teeth (18–19 versus 21–26).

Content. One species, Haitiophis anomalus , is included in the genus ( Table 1).

Distribution. The genus is distributed in Hispaniola, including Ile de la Tortue ( Haiti) and Isla Beata ( Dominican Republic) ( Fig. 2 ).

Etymology. The generic name is derived from the Taino word Haiti (meaning high mountains) for the entire island now called Hispaniola and refers to the distribution of the genus.

Remarks. The single species of Haitiophis is one of the largest snakes in the family Dipsadidae , reaching 2.8 meters in total length and 2.0 meters in SVL (Powell & Henderson 1998; Thomas et al. 2007) and past morphological studies have had difficulty in determining its relationship to other alsophiine species ( Maglio 1970; Zaher 1999). Our molecular evidence from the 12S and 16S rRNA genes associates H. anomalus with Caraiba and Cubophis , but more data are needed to place it in the phylogeny with confidence. Maglio (1970) also noted that the species is closer to a Cuban species ( Cubophis cantherigerus ) than any other in the West Indies—in having similar vomer, postorbital, and supratemporal bones. We classify it here in a separate genus because it differs considerably in scalation from either Caraiba or Cubophis . Zaher et al. (2009) classified this species with Borikenophis portoricensis and other West Indian species including Cubophis vudii and Cubophis cantherigerus in Ocyophis Cope , but our results ( Figs. 1 and 4 ) refute that classification (see Remarks in Hypsirhynchus ).

Figures

FIGURE 2. Map showing the West Indies (including the southern tip of Florida above, Central America to the west, and the northern edge of South America below) and the distributions of the genera of the Tribe Alsophiini, Subfamily Xenodontinae, Family Dipsadidae.

FIGURE 1. A phylogeny of Alsophiini. Bayesian tree obtained from the combined data set of six genes (RAG 2, 12 S & 16 S rRNA, cytochrome b, ND 2 and ND 4; 3387 sites). Alsophis portoricensis portoricensis and A. p. anegadae have identical sequences at all genes sampled, and therefore the latter taxon is not shown. Values are ML bootstrap values above 70 % followed by Bayesian posterior probabilities above 90 %. The generic taxonomy in this tree reflects usage prior to this study and shows paraphyly and polyphyly of Alsophis (blue), Arrhyton (purple), and Antillophis (orange). See Table 1 and Figure 4 for the new classification proposed here.

FIGURE 4. A timetree of Alsophiini. Divergence times and credibility / confidence intervals are shown in Table 3. Plei = Pleistocene. The generic taxonomy in this tree reflects the new classification proposed here and detailed in Table 1.