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

We review the systematics of the Dendrophidion nuchale complex in Central America and northern South America andrecognize three species. The names D. nuchale (W. Peters) and D. clarkii Dunn apply to two of the species. The third isdescribed as a new species, D. rufiterminorum. It differs from D. clarkii and D. nuchale in coloration and hemipenial char-acters but all three species of the nuchale complex are very similar in scutellation characters. Dendrophidion nuchale isdistributed in the coast ranges and adjacent foothills of northern Venezuela, and in a seemingly disjunct population in theSerranía de Perijá in western Venezuela. The name clarkii was recently applied to all populations of the nuchale complexfrom Belize and Guatemala in the north to western Colombia and Ecuador in the south. Herein, we restrict the name D.clarkii to populations in lower Middle America (Costa Rica and Panama) and west of the Andes in Colombia and Ecuador.Dendrophidion rufiterminorum is distributed in northern Central America (Belize, Guatemala, northern Honduras) fol-lowed by a broad disjunction without records of the species throughout most of Honduras and Nicaragua; thereafter, a fewspecimens and photographs document the presence of D. rufiterminorum on the Caribbean versant of southern Nicaraguaand Costa Rica, and uplands of northwestern Costa Rica (Pacific versant). Two localities of sympatry between D. rufiter-minorum and D. clarkii are known in Costa Rica (one on the Atlantic versant, the other on Pacific versant). Nonetheless,there is sparse documentation of either species in Costa Rica. The populations referred to D. clarkii in southwestern CostaRica, the eastern half of Panama, and western Colombia and Ecuador need further study. Hemipenes of species of thenuchale complex are described. All three species have a pair of enormously enlarged sulcate spines and a regular lineararray of enlarged spines (spinose annulus) encircling the base of the apical region. These characters are also shared with D. dendrophis sensu lato but not other members of the dendrophis species group.