Morphological and molecular characterization of two new species of the genus Aporcelinus Andrássy, 2009 (Nematoda, Dorylaimida, Aporcelaimidae) from the USA, with new insights on the phylogeny of the genus.

Abstract

Two new species of the genus Aporcelinus from the USA are described and illustrated. Aporcelinus floridensis sp. n. is characterized by its 1.12-1.52 mm long body, lip region offset by marked constriction and 14.5-17.0 μm broad with perioral liplets, odontostyle 16.5-20.0 μm at its ventral side and 1.1-1.2 times the lip region diameter, neck 316-395 μm long, pharyngeal expansion occupying 43-48% of total neck length, uterus simple and 33-56 μm long or 0.8-1.2 times the corresponding body diameter, V = 48-54, female tail conical (36-49 μm long, c = 27-41, c' = 1.2-2.0) with finely rounded terminus and no hyaline portion, and male absent. Aporcelinus paolae sp. n. is characterized by its 1.29-1.80 mm long body, lip region offset by marked constriction and 14-16 μm broad, odontostyle 15-17 μm at its ventral side and 1.0-1.1 times the lip region diameter, neck 314-397 μm long, pharyngeal expansion occupying 43-53% of total neck length, uterus tripartite and 128-164 μm long or 2.6-3.6 times the corresponding body diameter, V = 53-57, female tail conical (30-39 μm long, c = 40-51, c' = 1.1-1.3) with finely rounded terminus and variably re-curved dorsad, male tail conical (27-36 μm, c = 39-59, c' = 0.9-1.2), ventrally straight and dorsally convex, spicules 48-54 μm long, and 7-9 irregularly spaced ventromedian supplements lacking hiatus. The analyses of the D2-D3 expansion segments of 28S rRNA (LSU) gene sequences of the two new species confirmed the monophyly of the genus, based upon currently available data, showing a close relationship between the genera Aporcelinus and Makatinus, and justified the placement of Aporcelaimellus, Makatinus and Aporcelinus under the subfamily Aporcelaimellinae.