Twelve species (Bothriopsis bilineata, B. oligolepis, B. taeniata, Bothrocophias microphthalmus, Bothrops andianus, B. atrox, B. jonathani, B. moojeni, B. neuwiedi, B. sanctaecrucis, Crotalus durissus, Lachesis muta) and five genera of pitvipers are known from Bolivia. Known ranges of several species are expanded to accommodate recently collected material and Bothrops andianus is reported from Bolivia. The holotypes of Bothrops andianus and Lachesis peruvianus are redescribed. Bothriopsis oligolepis (Werner) is shown to be synonymous with Lachesis peruvianus Boulenger rather than L. chloromelas. We designate a lectotype of Bothriopsis chloromelas (Boulenger) and apply this name to the ornately patterned forest pitviper endemic to the northern and central Andes of Peru. Morphological variation and reproductive data are reported for B. sanctaecrucis. References to Bolivian specimens of B. jararacussu are based on misidentifications of B. sanctaecrucis. Although the known ranges of B. brazili, B. jararacussu, and Bothrocophias hyoprora approach Bolivia's borders, these species have not yet been collected within the country. A rectangular loreal is rare in pitvipers and may be a synapomorphy of two small Andean pitvipers: B. andianus and B. lojanus.

A new diminutive, long-tailed species of African wormsnake related to Leptotyphlops bicolor is described from Nigeria. The new species differs from L. bicolor by possessing a single anterior supralabial, a longer tail with fewer subcaudals, and the absence of brown pigment and an apical spine on the tail tip. The new species, which with L. bicolor, L. broadleyi, and L. sundewalli form the L. bicolor species group, shares characteristics with several New World taxa; these characteristics are probably plesiomorphic in the Old World radiation of Leptotyphlops.

Reexamination of the cranial anatomy of the abundant Late Permian dicynodont Diictodon confirms suggestions that only one species, D. feliceps, is recognizable. This monotypic genus is highly distinctive, being characterized by such features as a palatal notch, a large dentary table with a medial cutting blade, and the absence of postcanine teeth. Numerous anatomical variations exist within D. feliceps, but many appear biologically insignificant and show no apparent correlation with one another of with locality or stratigraphic position. However, statistical analysis reveals the presence of several features that correlate with the presence of canine tusks, including an occipitally positioned postparietal bone and the presence of a boss surrounding the pineal opening. This suggests that tusked and tuskless specimens do indeed represent distinct biological categories, but it seems highly probable that they are divisions within a single species (most probably opposite sexes) rather than distinct species. It is hoped that the detailed osteological description of the Diictodon skull presented here will provide useful data for future phylogenetic analyses of dicynodonts.