Dendrophidion clarkii

Cadle, John E. & Savage, Jay M., 2012, Systematics of the Dendrophidion nuchale complex (Serpentes: Colubridae) with the description of a new species from Central America, Zootaxa 3513, pp. 1-50 : 40-41

Dendrophidion clarkii (AMNH 109719, Colombia. Fig. 28 , left hemipenis)

Total length 29.9 mm. Overall form bulbous, constricting slightly proximal to the flounces and expanding again distally. Tip of the apex very slightly bilobed. Sulcus spermaticus simple, centrolineal, and with a distinctly flared tip, ending just short of the middle of the apex.

Base of the hemipenis with scattered minute spines. Enlarged sulcate spines present (one on right side of sulcus slightly more proximal, 5.05 mm long measured along topside; left spine about 4.9 mm long). Enlarged sulcate spines followed by a nude gap before the array of smaller spines. On the asulcate side are two enlarged asulcate spines (3.9 mm and 2.5 mm in length). Distal to these enormous spines are two or three irregular rows of much smaller spines, followed immediately by a spinose annulus containing 13 larger spines. Adjacent to the sulcus the spines in the array are somewhat larger than those farther away; the spines in the annulus are separated from the sulcus by one longitudinal row of these somewhat larger spines. Total number of spines on the hemipenis about 46.

Distal to the spines are about four rows of flounces/calyces with crenulated edges (more flounce-like proximally and toward the sulcate side; more calyx-like distally and toward the asulcate side). Proximal flounces broader than more distal ones, with gradual decrease in width distally and concomitant decrease in crenulation of the edges. The distal row of flounces/calyces has smooth edges. Flounces/calyces spinulate, with the points of their crenulated edges occupied by the tips of spinules. Spinules and crenulations much more densely arrayed and more prominent in the transverse walls of the calyces/flounces than in the longitudinal walls, which are mostly smoothedged.

Distal to the flounces/calyces around the periphery of the apex are some irregular calyces with low, thick, fleshy walls. Tip of the apex is nude but with a somewhat tubercular or rugose surface.

Variation and remarks. Five other everted or partially everted hemipenes of Dendrophidion clarkii from three specimens (LACM 148553–54, FMNH 165567) had 10–12 spines in the spinose annulus; two of these had total spine counts of 42 and 48. As described before (see species account), the hemipenis of the holotype has 15 spines in the annulus and a total of 52 spines. The lengths of twelve retracted hemipenes of Dendrophidion clarkii we examined were from the proximal portion of subcaudal 6 to the middle of subcaudal 10 with the following frequencies: to the proximal portion of subcaudal 6 (N = 1), suture between subcaudals 6 and 7 (1), proximal portion or the middle of subcaudal 7 (3), suture between subcaudals 7 and 8 (2), suture between subcaudals 8 and 9 (3), suture between subcaudals 9 and 10 (1), middle of subcaudal 10 (1).

Figures

FIGURE 28. Everted hemipenis of Dendrophidion clarkii in sulcate and asulcate views (AMNH 109719, Cauca department, Colombia).