Oxysomatium brevispiculum n. sp. (Nematoda: Cosmocercidae) from Amphisbaena alba Linnaeus (Squamata, Amphisbaenidae) in the Cerrado Biome from Brazil

In the present study, we describe Oxysomatium brevispiculum n. sp. (Ascaridida: Cosmocercidae) parasitizing Amphisbaena alba Linnaeus (Squamata: Amphisbaenidae) in the municipality of Uberlândia, Cerrado Biome, Minas Gerais, Brazil. Oxysomatium brevispiculum n. sp. differs from its congeners by having shorter spicules and by the number and arrangement of caudal papillae. The males of the new species have a precloacal unpaired papilla and can be easily distinguished from O. caucasicum in which this morphological trait is absent. Oxysomatium brevispiculum n. sp. differs from the other three species of the genus by the number and arrangement of caudal papillae, with 13 pairs + 1 unpaired precloacal papilla, arrangement 8+1:2:3, while O. brevicaudatum has 14–16 pairs +1 unpaired papilla, and 7–9+1:1:6 arrangement, O. petrolinensis has 16 pairs +1 unpaired papilla, and 8+1:1:7 arrangement, and O. dollfusi with 15–16 pairs +1 unpaired papilla, and 8–9+1:1:6 arrangement. Oxysomatium brevispiculum n. sp. is the fifth species of this genus, the second species in a Neotropical host, and the first species of this genus described in amphisbaenid hosts. In addition, the present study provides an identification key for the species of this genus.