Rhinocerophis, GARMAN, 1881

Fenwick, Allyson M., Gutberlet Jr, Ronald L., Evans, Jennafer A. & Parkinson, Christopher L., 2009, Morphological and molecular evidence for phylogeny and classification of South American pitvipers, genera Bothrops, Bothriopsis, and Bothrocophias (Serpentes: Viperidae), Zoological Journal of the Linnean Society 156 (3), pp. 617-640 : 630-631

RHINOCEROPHIS GARMAN, 1881

Type species: Rhinocerophis nasus ( Garman, 1881) , a junior synonym of Bothrops ammodytoides ( Leybold, 1873) .

Etymology: The generic name is derived from the Latin Rhinoceros , meaning ‘nose-horn’, referring to the strongly upturned snout of R. ammodytoides , and ophis, meaning ‘snake’. Names ending in this suffix are masculine.

Content: Rhinocerophis alternatus , R. ammodytoides , R. cotiara , R. fonsecai , R. itapetiningae , and R. jonathani .

Definition: Members are short to elongate, of moderate girth to stout, and are terrestrial, lacking a prehensile tail. Dorsal colour brown to black, with spadeshaped dorsal markings, generally with spots between spades ( R. alternatus , R. fonsecai ; no spots between spades in R. jonathani , and sometimes missing in R. cotiara ), or trapezoidal dorsal markings, with spots between trapezoids ( R. itapetiningae ), or with chequered pattern ( R. ammodytoides ). Spadeshaped dorsal markings and a postorbital stripe on head, with distinctive black bars on the gulars of R. alternatus , R. cotiara , R. fonsecai , and R. jonathani .

There are 3 or 4 interoculabials, 7–10 supralabials, 5–16 keeled intersupraoculars, 5–12 scales between the first postcanthals, 25–40 interrictals, 145–181 ventrals, 23–35 dorsal scale rows at midbody, and 25–55 divided subcaudals. Prelacunal and second supralabial are separate, with either one or no subfoveal scale row, and with supralacunal separate from middle preocular (fused in R. jonathani and in one specimen of R. alternatus ). Loreal wider than high to higher than wide, and loreal pit ventral to nasoorbital line. Postnasal not in contact with first supralabial. Dorsal scales keeled with typical thin ridge.

From an examination of the hemipenes of R. alternatus : mesial spines on hemipenes present, spinulate calyces distal to crotch, and many (> 12) lateral spines.

From an examination of osteological samples of R. cotiara , R. fonsecai , and R. itapetiningae : 1 or 2 palatine teeth, 10–14 pterygoid teeth, and 11–13 dentary teeth. Maxillary fang shorter than height of maxilla, medial wall of pit cavity in maxilla well developed. Lateral margin of head of ectopterygoid narrow, single pit on posterior surface of anterior end of ectopterygoid, ectopterygoid shaft narrow and not tapered, and base with a long overlapping projection. Choanal process of palatine positioned anteriorly to medially, and moderately high to attenuate. Supratemporal thick and rounded, with a small projection. Meckellian foramen single; angular and splenial partially to completely fused.

Diagnosis: Rhinocerophis differs from other South American pitvipers in 27 mitochondrial characters, and in having few (1 or 2) palatine teeth (versus 3–6 teeth), which is a morphological synapomorphy ( Table 4). Distribution in southern South America, combined with terrestrial habitat in open areas, grasslands, swamps, or broad-leaf and Araucaria forests, distinguishes this genus from others (see Table 4). Rhinocerophis individuals have the maxillary fang shorter than the height of the maxilla, and show black bars on the gular scales of some species ( R. alternatus , R. cotiara , R. fonsecai , and R. jonathani ). Rhinocerophis have fewer subcaudals (25– 55) than the other genera (31–86), and some specimens have high numbers of supralabials (7–10, also seen in Bothropoides ; other South American genera have 7–8). Rhinocerophis differs from Bothrops and Bothriopsis in having the prelacunal scale separated from the second supralabial. It differs from Bothriopsis in the lack of green coloration, and in the lack of a prehensile tail. It differs from Bothrocophias in the lack of tuberculate keels on posterior dorsal scales. Almost all species differ from Bothrocophias in colour pattern: whereas Bothrocophias species have spadeshaped dorsal markings lacking spots between the spades, Rhinocerophis species have spots between the spades ( R. alternatus , R. cotiara , and R. fonsecai ), have trapezoidal markings with spots between them ( R. itapetiningae ), or have a checkered pattern ( R. ammodytoides ). Only R. jonathani lacks spots between spades, but it can be distinguished by the presence of black bars on the gular scales, as mentioned above.

Distribution: Southern South America: in southeastern Brazil, central and southern Bolivia, Paraguay, Uruguay, and Argentina ( Campbell & Lamar, 2004). See Campbell & Lamar (2004) for range maps of individual species.