Apratylenchus vietnamensis gen. n., sp. n. and A. binhi gen. n., sp. n., sedentary Pratylenchidae (Nematoda: Tylenchida) from coffee in Vietnam, with proposal of Apratylenchinae subfam. n.

Abstract

Abstract Apratylenchinae subfam. n. is proposed within the Pratylenchidae to include Apratylenchus gen. n. and two new species, A. vietnamensis gen. n., sp. n. and A. binhi gen. n., sp. n., from coffee plantations in Vietnam. Apratylenchus gen. n. is distinguished by the presence of transverse rows of cuticular tubercles on the annuli and by sexual dimorphism in which the males are stout and cylindrical, but mature sedentary females are club-shaped. The sedentary females are broadest in the posterior third although narrowing posterior to the vulva (V ≥ 85%). The female cephalic region is low and dome-shaped with all labial sectors fused to one another and the oral disc and the pharyngeal glands overlap the intestine ventrally. Males have a weak stylet with reduced knobs and a conical tail with a blunt terminus, arcuate spicules and a non-protrusible gubernaculum. Apratylenchus vietnamensis gen. n., sp. n. is characterised by a sedentary mature female with a 368-515 μm long club-shaped body, cephalic region low, dome shaped with three annuli, body annuli bearing a single or double row of refractive tubercles, stylet 17.0-19.9 μm long, V = ca 88-92, spermatheca filled with sperm and males known, if rarely found, in the type population. Males have a weak, 15 μm long stylet with reduced knobs, 16 μm spicules, a non-protrusible gubernaculum and low bursa. It differs from A. binhi gen. n., sp. n., the only other nominal species of the new genus, by longer female body (368-515 vs 326-364 μm), longer distance from anterior end to anus (353-512 vs 310-348 μm) and longer stylet (17.0-19.9 vs 14.7-16.9 μm). In addition, the spermatheca is filled with round sperm vs empty in A. binhi gen. n., sp. n. and the cuticle has less densely spaced and less pronounced tubercles. D2/D3 sequences of the 28 rDNA gene clearly support the separation of Apratylenchus gen. n. from other Pratylenchidae and further distinguish the two new species from each other.