Dendrophidion rufiterminorum

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 : 42

Dendrophidion rufiterminorum (LSUMZ 8901, holotype. Fig 29 , left hemipenis)

Total length of hemipenis about 23 mm. The hemipenis was everted completely in the field except for a small portion of the apex. The tip of the apex was everted manually by pushing outward from the inside with a small probe; this manual eversion accounts for the shape of the apex in Fig. 29 . The tip of the sulcus and all other apical surfaces are completely visible. The base of the organ was twisted during fixation, making precise configuration of the base difficult to discern. Before full eversion the retractor penis magnus was pulled back through the base of the organ to examine its internal attachment to the hemipenis; it was divided for about 3 mm.

Sulcus spermaticus simple, centrolineal, with a distinctly flared tip ending in the center of the apex between two shallow depressions (points of internal attachment of the retractor branches). The distinct broadening of the sulcus tip almost gives the appearance of being terminally divided, probably due to manual eversion of the apex; if the tissue were fully ‘relaxed’ the tissue between the sides of the sulcus would probably flatten out with full eversion, leading to a flared appearance similar to D. nuchale ( Fig. 27 ). It is unclear whether the apex is bilobed. It does not appear to be so, but because of the manual eversion it is uncertain whether the apical tissue would take on a more bilobed appearance if it were fully relaxed and maximally inflated.

Basal portion of hemipenis nude, seemingly in a broader area on the left side of the sulcus than on the right side. A band of minute spines occupies the portion of the hemipenial body just proximal to the enlarged sulcate spines. This band is broad next to the sulcus spermaticus but much narrower and with more sparsely deployed spines on the asulcate side. On each side of the sulcus just proximal to the array of spines is a bulbous projection (the one on the right side larger and more rounded than the one on the left); the minute spines occupy these projections.

Enlarged sulcate spines very large (about 4.5 mm long measured along their upper distal surface); the spine left of the sulcus is closer to the sulcus than the one on the right. In approximate alignment with the enlarged sulcate spines is a regular row of moderately enlarged spines encircling the hemipenis except for the spaces between each enlarged sulcate spines and the sulcus spermaticus. Distal to the enlarged sulcate spines and the aligned row are three or four loosely arranged rows of much smaller spines, followed by a spinose annulus. Some of the very small spines between the proximal and distal rows are mere nubbins. Twenty-three spines in the spinose annulus (24 in the annulus of the right hemipenis). Total number of spines about 90 (93 for the right hemipenis). There are no distinctly enlarged asulcate spines, the spines in the first row instead being of uniform size on the asulcate side ( Fig. 29 , asulcate view).

Distal to the spines are about four or five rows of poorly developed calyces; the proximal row consists of pockets underneath the proximal border of the second row, with no distinct wall between these pockets and the spinose annulus. These calyces have smooth borders (no projecting spinules or papillae) that are mostly straight, sometimes slightly undulating or crenulated. The transverse borders of the first couple of rows have some embedded spinules, not very distinct, but distal calyces seem to lack these entirely. Calyces become shallower distally (with lower walls), such that calyces in the distalmost row might largely disappear upon full inflation and stretching of the apex of a fresh hemipenis. Apex distal to the calyces is entirely nude and relatively smooth.

Variation and remarks. We have seen no other fully everted hemipenes of Dendrophidion rufiterminorum . A few details are available from partially everted organs of another specimen from Belize (UCM 25846). The left and right hemipenis each had 22 spines in the spinose annulus and about 86 and 87 total spines. The visible portion of the morphology of each is similar to that of LSUMZ 8901, including slightly enlarged spines in the proximal row compared to more distal spines in the array except for those in the spinose annulus. The length of six retracted hemipenes from Belize and Guatemala were to the middle of subcaudal 5 (1), the suture between subcaudals 5 and 6 (2), the suture between subcaudals 7 and 8 (1), and to the middle of subcaudal 8 (2).

Figures

FIGURE 27. Hemipenis of Dendrophidion nuchale, oblique apical view (TCWC 59022). Sulcus spermaticus is the deep furrow in the center of the photograph.

FIGURE 29. Everted hemipenis of Dendrophidion rufiterminorum in sulcate and asulcate views (LSUMZ 8901 [holotype], Cayo District, Belize). The tip of the apex was manually everted and the base is twisted.