Pseudoangiostoma onychodactyla gen. n. comb. n. (Nematoda: Angiostomatidae) parasitic in Onychodactylus spp. (Caudata: Hynobiidae) salamanders from Japan.

The new genus Pseudoangiostoma gen. n. (Nematoda: Angiostomatidae) was established on the basis of the type species Pseudoangiostoma onychodactyla comb. n. (syn. Angiostoma onychodactyla), which parasitizes the stomach and intestine of some species of the genus Onychodactylus (Amphibia: Hynobiidae) in Japan. Pseudoangiostoma gen. n. differs from the genus Angiostoma by having a lower inverted truncated cone-shaped buccal cavity, a thicker and strongly curved buccal wall, and for parasitizing hosts of the order Caudata. The phylogenetic pattern provided substantial suppot for the new genus, exhibiting two major divergent lineages (diverged in terrestrial gastropods vs. salamanders). This study indicated that P. onychodactyla comb. n. did not originate from host-switching event from terrestrial gastropods to salamanders. However, other species of Angiostoma parasitic in amphibians and reptiles are still considered insertae sedis.