Ditylenchus dactylonae n. sp. (Tylenchomorpha: Anguinidae), an associate of Cynodon dactylon (L.) Pers. in the USA

A new species of the genus Ditylenchus was recovered from rhizosphere soil of a 'TifEagle' hybrid bermudagrass (Cynodon dactylon (L.) Pers. x C. transvaalensis (Burtt-Davy)) putting green located at the Pee Dee Research & Education Center, Clemson University, Florence, SC, USA. It is described herein as Ditylenchus dactylonae n. sp. and is characterised by possessing the combined characters of a medium body size (682-815 & mu;m in females; 618-718 & mu;m in males), six incisures at the lateral fields, a delicate stylet (7.6-8.0 & mu;m) with rounded knobs, a bottle-shaped basal pharyngeal bulb (BPB), an excretory pore (EP) near anterior end of BPB, a posteriorly located vulva (V = 78-83%), a reflexed ovary, a uterus with crustaformeria anteriorly and nearly spherical structure posteriorly, a post-vulval uterine sac (30-50% of the vulva-anus distance), an elongate conoid and ventrally bent tail, a tylenchoid spicule (17-18 & mu;m), and a leptoderan bursa. Ditylenchus dactylonae n. sp. was differentiated from other sequenced species by the partial small subunit (SSU) rRNA gene, D2-D3 expansion segments of the large subunit (LSU) rRNA gene and internal transcribed spacer (ITS) rRNA. Phylogenetic analysis revealed that D. dactylonae n. sp. belongs to the D. dipsaci-group, and is sister to D. medicaginis and/or D. ferepolitor based on SSU 18S, LSU D2-D3 and ITS sequences.