Description of Ruehmaphelenchus americanum n. sp. (Nematoda: Aphelenchoididae) found in Loblolly pine from the USA

Abstract

Summary Ruehmaphelenchus americanum n. sp., isolated from southern yellow pine (Pinus taedae L.) from the USA is described and figured. It is characterised by a relatively stout body (a = 30 for females and males), three lines in the lateral field, both oocytes and spermatocytes arranged in two rows, male spicules relatively small (14-18 μm) with weakly developed condylus and rostrum, short tail with a bluntly pointed tip, seven papilliform genital papillae present, female vulva positioned at ca 82% of body length, vulval lips slightly protruding, post-uterine branch extending two-thirds of vulva to anus distance, tail cylindrical, ca two anal body diam. long, terminus forming a spike-like projection or mucron, 7.6-12.2 μm long, with pointed tip. The new species can be separated from 11 known species (except R. thailandae) by male genital papillae arrangement (the second and third pair adjacent vs separated). Detailed phylogenetic analysis based on 18S and 28S D2-D3 region ribosomal RNA (rRNA) sequences has confirmed the status of this nematode as a new species.