n. sp. (Cestoda: Proteocephalidae) from the saw-scaled viper, Stemmler (Ophidia: Viperidae), one of the world's deadliest snakes, from the United Arab Emirates.

n. sp. (Cestoda: Proteocephalidae) is described from the intestine of one of the world's deadliest snakes, the saw-scaled viper Stemmler (Ophidia: Viperidae) in the United Arab Emirates. The new species differs from other species of the non-monophyletic by the position of testes in two longitudinal lines on both sides of the uterus, and by the large size of an embryophore (diameter of 44-55 μm less than 40 μm in other species). Phylogenetic reconstructions based on DNA and concatenated DNA + COI datasets place the new species among proteocephalids from unrelated zoogeographical realms but mostly infecting venomous snakes. In all analyses, . n. sp. exhibited a strongly supported sister relationship with Rambeloson, Ranaivoson et de Chambrier, 2012, a parasite of a pseudoxyrhophiid snake endemic to Madagascar. Despite a shared close evolutionary history between these taxa, morphological synapomorphies remain unclear, which impedes the erection of a new genus to accommodate them. A list of the 71 tapeworms of the former, non-monophyletic subfamily Proteocephalinae, parasitising snakes and lizards, including , and the phylogenetically closely related from opossum, with selected characteristics, is also provided, together with a checklist of helminth parasites reported from .