Description of Longidorus sanlitanensis n. sp. (Dorylaimida: Longidoridae) from the rhizosphere of Melilotoides ruthenica and Chamaerhodos erecta in China

Abstract

Longidorus sanlitanensis n. sp. was recovered from the rhizosphere of Melilotoides ruthenica and Chamaerhodos erecta in the Inner Mongolia Autonomous Region, P.R. China, and was described and illustrated using morphological and molecular data. The new species is characterised by medium body length of females (4.0-4.8 mm), lip region anteriorly rounded and separated from the rest of the body by a depression, pocket-shaped amphidial pouches, the guiding ring located at 58.4-66.0 μm from the anterior end, odontostyle and odontophore 107.2-114.6 and 71.6-77.8 μm long, respectively, the pharyngeal bulb 68.7-79.7 μm long, a short conical tail with a broadly rounded terminus, four juvenile developmental stages (J1 was not detected) and males absent. By similarities in the distance of the guiding ring from the anterior body end, body and odontostyle length and lip region shape, the new species was compared with nine similar species, namely: L. litchi, L. diadecturus, L. fursti, L. himalayensis, L. jonesi, L. wiesae, L. macromucronatus, L. fangi and L. zhengi. The matrix code of the new species is: A4-B2-C5-D4-E1-F2-G2-H12-I2-J1-K?. The phylogenetic relationships of the new species with other relevant species were reconstructed using near-full-length 18S, ITS1 and 28S D2-D3 regions of rRNA gene and the resulted topologies were discussed. In 18S phylogeny, L. sanlitanensis n. sp. formed a clade with L. litchi inside a major clade, including species with a posteriorly located guiding ring, and in 28S phylogeny it showed close relationships with species having a posteriorly located guiding ring. This is the 22nd Longidorus species recorded from China.