Morphological and molecular characterizations of Africanema multipapillatum sp. nov. (Nematoda, Enoplida) in intertidal sediment from the East China Sea

Abstract

A new nematode species, Africanema multipapillatum sp. nov., is described from a sand beach in the East China Sea. The new species is assigned to the family Trefusiidae based on both the morphological and molecular analyses. Africanema multipapillatum sp. nov. is a distinct species characterized by its toothless and spacious buccal cavity, jointed labial setae, non-spiral and elongate groove-shaped amphidial fovea, faintly striated cuticle, and a single posterior ovary. Within the family Trefusiidae, the new species is most similar to the monotypic genus Africanema, but differs distinctly from Africanema interstitiale by the long and curved spicules with gubernaculum apophysis, long and slim sperm cells, and the lack of pharyngeal papillate supplements. Molecular phylogenetic analyses indicate that Africanema multipapillatum sp. nov. and the genera Rhabdocoma and Trefusia always fell within a single clade of the family Trefusiidae, where it is closely related to Rhabdocoma. Thus, we propose assigning the genus Rhabdocoma from the subfamily Trefusiinae to the subfamily Halanonchinae.