Two known species of Aporcelinus Andrassy, 2009 (Dorylaimida: Aporcelaimidae) from Vietnam, with the first molecular study of the genus

Two poorly known species of the genus Aporcelinus are characterised in detail and re-defined, including line drawings, LM and SEM pictures, on the basis of abundant material collected from natural habitats in Vietnam. Aporcelinus granuliferus is distinguished by its body 0.93-1.70 mm long, lip region offset by constriction and 15-17 mu m broad, odontostyle 17-22 mu m long, neck 270-403 mu m long, pharyngeal expansion 132-214 mu m long or 47-52% of total neck length, presence of a dorsal cell mass at the pharyngo-intestinal junction, uterus a simple tube 38-57 mu m or 0.7-0.9 times than the corresponding body diam. long, V = 46-55, female tail conical (29-55 mu m, c = 24-41, c' = 0.7-1.9) with acute tip and lacking a hyaline region. Aporcelinus jiaonanensis is recognisable by its 1.11-1.71 mm long body, lip region offset by weak constriction with small inner liplets and 17-20 mu m broad, odontostyle 20-23 mu m long, neck 307-436 mu m long, pharyngeal expansion 154-234 mu m long or 47-55% of total neck length, uterus tripartite and 56-97 mu m long or 1.0-1.5 times the corresponding body diam., V = 51-59, tail conical (23-43 mu m, c = 29-68, c' = 0.7-1.3) with finely rounded tip and a distinct hyaline region, spicules 51 mu m long, and nine, regularly spaced, ventromedian supplements, two of them within the range of the spicules. Analysis of three D2-D3 28S rDNA gene sequences of A. jiaonanensis, the first from a representative of the genus, reveals a close relationship with members of Aporcelaimellus