Laimaphelenchus africanus n. sp. (Tylenchomorpha: Aphelenchoididae) from South Africa, a morphological and molecular phylogenetic study, with an update to the diagnostics of the genus

Abstract

A newly recovered population of the genus Laimaphelenchus from a dead maritime pine wood sample in Potchefstroom, South Africa, representing a new species, named L. africanus n. sp., is herein described and illustrated based on morphological and molecular data. The new species is mainly characterized by the following: 750 987 ?m long females; a cephalic region with no disc and six cephalic lobs not divided by ribs; a 10.0 12.5 ?m long stylet; four incisures in the lateral field; secretory-excretory pore (SE-pore) at slightly posterior to the nerve ring; vulva with a well-developed anterior flap, vagina with two well-developed sclerotized pieces; post-vulval uterine sac (PUS) 63 125 ?m long; tail conical, 30 44 ?m long, ventrally curved with a subventral stalk in terminus, lacking tubercles, with six to nine small projections at the tip in scanning electron microscopy (SEM); and rare males with 17 ? m long spicules. The new species was morphologically compared to those species of the genus with a stalk in tail terminus, lacking tubercles, a vulval flap and four incisures in the lateral field viz., L. liaoningensis, L. preissii, L. simlaensis, L. sinensis, L. spiflatus, and L. unituberculus. Phylogenetically, the new species was placed into the major Laimaphelenchus clade using partial large subunit ribosomal DNA (LSU rDNA D2-D3) sequences. An overall literature review corroborated the presence of the stalk (currently with two main groups) at the tail end is the main characteristic trait delimiting the genus. A compendium based on the characters of the stalk, presence/absence of a vulval flap in females and number of the lateral lines was also established.