A new ring nematode, Mesocriconema abyanehense sp. n. (Nematoda: Criconematidae), from Central Iran

Ring nematodes of the genus Mesocriconema are among the most diverse genera within the family Criconematidae. They are polyphagous, migratory, root-ectoparasites of plants, with more than 90 described species. During a nematological survey in Esfehan Province, one new Mesocriconema species was isolated from the rhizosphere of meadow grasses. In the present study, this new species is described based on morphological, morphometric and molecular data. It is characterised by a slightly curved body 546–741 μm in length, with 97–114 cuticular body annuli with smooth to rough margins; the anterior margin is mostly not indented laterally, although a few specimens display various degrees of indentation. Anastomosis was very rare and observed in only two individuals. The lip region is not offset, consisting of three annuli, tapering and slightly conical. Small submedian lobes and a labial plate are present but not very pronounced. The stylet is robust (58–67 μm) with well-developed knobs. The vulva is open with a simple anterior lip and a straight vagina. The spermatheca is filled with globular sperm. The tail is conical, with the last annulus more or less rounded; the tail tip is usually single, but sometimes multi-lobed. Discussions are made on the characterisation of M. abyanehense sp. n. from the most closely related species, M. abolafiai, and several other species having similar tail shape. Molecular phylogenetic analyses based on the D2–D3 segments of large subunit (LSU) and COI mtDNA sequences indicate that M. abyanehense sp. n. is closely related to M. abolafiai and M. rusticum.http://www.zoobank.org/urn:lsid:zoobank.org:pub:B555FBD9-B653-4974-9C8B-9C8494ABF183