Microlaimidae (Microlaimoidea: Nematoda) from the Indian Ocean: description of nine new and known species

Abstract

Nine species are described from the genera Aponema Jensen, 1978, Bolbolaimus Cobb, 1920, Calomicrolaimus Lorenzen, 1976, Ixonema Lorenzen, 1976 and Microlaimus de Man, 1880. Aponema decraemerae sp. n. is characterised by sexual dimorphism in the size of the amphids, short cephalic sensilla, spicules with a poorly developed capitulum and conical cylindrical tail with a pointed tip. Aponema mnazi sp.n. is characterised by short cephalic sensilla, head set off from the rest of the body by a fine constriction, spicules with a pointed anterior tip, one precloacal supplement located at 7 μm from the cloaca opening and a short tail with a blunt tip. Bolbolaimus bahari sp. n. is characterised by cuticular annules with fine interannular spaces, papilliform labial sensilla and short setiform cephalic ones, curved spicules with a poorly developed capitulum. Bolbolaimus abebei sp.n. is characterised by setiform outer labial and cephalic sensilla and spicules with a well-developed beak shaped capitulum. Calomicrolaimus jenseni sp. n. is characterised by an elongate cervical region, small (2 μm wide) amphids located at 44–54% of the pharyngeal length from the anterior and a conical tail with a pointed tip. Ixonema deleyi sp. n. is characterised by a small body (<400 μm long) an elongate cervical region, small (1–2 μm wide) circular amphids with rod-like corpus gelatum located at 30–45% of the pharyngeal length from the anterior. Microlaimus texianus Chitwood, 1951 is characterised by sexual dimorphism in the size of the amphids and presence of five pre-cloacal supplements. Microlaimus minutus sp. n. is characterised by a small body (< 300 μm long) that is often curved or coiled, amphids that are 55–60% cbd and located at 11–15 μm away from the anterior end and short (12–15 μm long) simple spicules. Microlaimus pwani sp.n. is characterised by prominent cuticular annules, long cephalic sensilla, amphids that are 50–55% cbd and located at 11–13 μm from the anterior end and long sausage-shaped striated sperms.