FOUR NEW SPECIES OF THE GENUS RHIGONEMA COBB, 1898 (NEMATODA: RHIGONEMATIDA: RHIGONEMATIDAE)

Abstract

Four new species of Rhigonema Cobb, 1898, R. acrulocantha sp. n., R. tomentosum sp. n., R. tribonophora sp. n. and R. villosum sp. n. from the intestine of two unidentified species of giant diplopod (Diplopoda; Spirobolida) from Papua New Guinea are described and illustrated. Three of the species possess a vaginal diverticulum whereas R. tribonophora sp. n. has a long, anteriorly directed and then doubly reflexed, overjector. R. acrulocantha sp. n. is unique amongst nominal Rhigonema species because of the highly developed pilose region extending from the head to the beginning of the tail in both sexes, the microtrichs being heavily cuticularized and spiniform. R. tomentosum sp. n. and R. villosum sp. n. are similar, yet morphologically distinct and from different hosts and may represent sibling species. SEM studies of the en face and pilose regions of three of the species are presented.