Clark's Forest Racer

description

Description (27 males, 23 females). Table 1 summarizes size, body proportions, and meristic data for Dendrophidion clarkii throughout its geographic range. Largest specimen (USNM 150138 from Panama) a female 1550 + mm total length, 942 mm. Largest male (CAS 119604 from Colombia) 1521 mm total length, 909 mm SVL. Tail 34 – 40 % of total length (52 – 68 % of SVL) in males; 34 – 41 % of total length (52 – 69 % of SVL) in females. Dorsal scales usually in 17 – 17 – 15 scale rows, the posterior reduction usually by fusion of rows 2 + 3 (N = 26), 3 + 4 (N = 18), or loss of row 3 (N = 8) at the level of ventrals 83 – 115. Ventrals 158 – 175 (averaging 165) in males, 163 – 172 (averaging 167.2) in females; usually two preventrals anterior to ventrals (occasional specimens have one preventral). Anal plate divided in 35 out of 44 specimens (80 %), single in 8 (17.8 %), and partially divided in 1 specimen. Six of the specimens with a single anal plate are from Costa Rica and western Panama (one is from Ecuador, one probably from Colombia; the partially divided anal plate is in an Ecuadorian specimen). Subcaudals 139 – 161 (averaging 148.4) in males, 139 – 159 (averaging 148.9) in females. Dor

Systematics of the Dendrophidion nuchale complex (Serpentes: Colubridae) with the description of a new species from Central America

diagnosis

Diagnosis. Dendrophidion clarkii is characterized by (1) Dorsocaudal reduction from 8 to 6 occurring posterior to subcaudal 25 (range, 27 – 65); (2) anal plate usually divided (single in 8 of 45 specimens, partially divided in 1); (3) subcaudal counts> 135 in males and females; (4) head and anterior body of adults bright green, grading to brown posteriorly; (5) blackish or dark brown nuchal collar present in adults (less distinct or absent in juveniles); (6) posterior body brownish and having dark crossbands with embedded pale ocelli; tail brown to deep reddish, and either uniform (without crossbands) or with crossbands similar in overall pattern to posterior body; (7) ventral scutes in adults marked with narrow dark brown transverse lines across the anterior edge of each scute (Fig. 4); (8) total number of enlarged spines on the hemipenis relatively few ( 25 in D. clarkii). Single anal plates occur in the D. percarinatum group only in some individuals of D. paucicarinatum. Three species in the D. percarinatum group (D. brunneum, D. bivittatum, and a new Ecuadorian species described by Cadle 2012 b) can have a green head or anterior body but these lack a blackish nuchal collar and

Systematics of the Dendrophidion nuchale complex (Serpentes: Colubridae) with the description of a new species from Central America

distribution

Distribution (Figs. 12, 13, 20). Dendrophidion clarkii as redefined herein (snakes with a distinct nuchal collar and vivid green anterior body in adults) is distributed from Costa Rica to western Ecuador. Locality records for D. clarkii in Costa Rica are shown in Fig. 12 along with the southernmost records of D. rufiterminorum (discussed in its species account). The distribution of D. clarkii in eastern Panama and western South America is shown in Fig. 13; see Fig. 20 in the species account for D. rufiterminorum for a panoramic view of the Central American distribution of D. clarkii. Records for D. clarkii within its distribution are rather spotty except in northwestern Ecuador and it seems likely that the geographic range is in fact fragmented. We discuss the distribution in detail to highlight these potential disjunctions. In Costa Rica Dendrophidion clarkii is known from two widely separated regions on the Pacific versant and from the Caribbean versant (Fig. 12). On the Pacific versant ten specimens document the species from the valley of the Río Térraba and one of its main tributaries (Río Coto Brus) in southern Puntarenas province. In northern Puntarenas a single specimen we r

Systematics of the Dendrophidion nuchale complex (Serpentes: Colubridae) with the description of a new species from Central America

etymology

Etymology. Dendrophidion clarkii is named after Herbert C. Clark, first director of the Gorgas Memorial Laboratory in Panama and overseer of the Panamanian Snake Census, which contributed immensely to knowledge of the snake fauna of Panama (see Dunn 1949, Myers 2003).

Systematics of the Dendrophidion nuchale complex (Serpentes: Colubridae) with the description of a new species from Central America