ABSTRACT Eutrachelophis, new genus is established to accommodate E. bassleri, new species, and E. steinbachi (Boulenger), new combination; a third species close to E. bassleri awaits naming. These taxa are placed in the Eutrachelophiini, new tribe, to express hypothesized relationship with the Xenodontini, which are defined by presence of hemipenial apical discs (a character lost in several species). The acalyculate spiny hemipenis of Eutrachelophis bassleri is unique among “xenodontines” in having a noncapitate, well-formed capitulum in the form of a nude dome; bifurcation is lacking even in the insertion of the major retractor muscle; the sulcus spermaticus is centrolineal in the retracted organ but becomes centrifugal during eversion. The hemipenis of Eutrachelophis steinbachi is strikingly different in being deeply divided, with long spiny lobes tipped with tufts of sender spines, but it resembles those of some other colubrids (e.g., South American Xenodon suspectus; African Mehelya poensis). Based on...