Description of Trichodorus marylandi n. sp. (Nematoda: Trichodoridae) from Maryland, USA

During nematode surveys in natural vegetation, a new species, described herein as Trichodorus marylandi n. sp., was identified in addition to Paratrichodorus species and Nanidorus minor from Maryland, USA, and three putative new Trichodorus species from California. Trichodorus marylandi n. sp. is about 1 mm long with a medium-sized onchiostyle 54 (47-59) ìm long. Males are characterised by a single ventromedian cervical papilla located anterior to the secretory-excretory pore, all three ventromedian precloacal supplements located anterior to the retracted spicules, and spicules 42 (38-44) ìm long showing a minor indentation at the level of the posterior border of the capsule of the protractor muscles. Females possess a short barrel-shaped vagina when the body is relaxed, and two sublateral body pores on each side, one up to four body diam. anterior to the vulva and one advulvar in position. A rare observation of a 'hood' ventrally attached to a moulting male juvenile was observed and illustrated. Trichodorus marylandi n. sp. is morphologically closest to T. obtusus. Based on recent information gained from molecular data for Trichodorus species that has revealed the occurrence of several cryptic species, T. proximus is temporarily accepted as a valid species until molecular data become available from topotype specimens. Phylogenetic relationships within trichodorids, as inferred from the analyses of the D2-D3 expansion segments of 28S rRNA and ITS2 rRNA gene analysis and a statistical parsimony network showing the phylogenetic relationships between COI haplotypes of T. obtusus and T. marylandi n. sp., are also provided.