MORPHOMETRIC STUDIES ON COOMANSUS JAIRAJPURI AND KHAN, 1977 (NEMATODA, MONONCHIDA) AND DESCRIPTIONS OF 2 NEW SPECIES FROM THE SUB-ANTARCTICREGION

Four known and two new species of the genus Coomansus Jairajpuri & Kha n, 1977, inhabiting different areas of New Zealand, the Antarctic Peni nsula, and Subantarctic America, are studied. A morphometric analysis is carried out to differentiate between C. gerlachei (de Man, 1904), C . mesadenus (Clark, 1960), C. composticola (Clark, 1960), C. intestinu s (Vinciguerra & La Rosa, 1990), C. meridionalis sp. n., and C. magell anicus sp. n. C. meridionalis sp. n. is characterized mainly by body l ength (2.10-2.65 mm), buccal cavity size (39-45 x 18-22 mu m), apex of the dorsal tooth at 84-95 % of the total buccal cavity measured from the base, spicule length (94-110 mu m), very slender lateral guiding p ieces, conoid and ventrally curved tail with rounded terminus, and abs ence of spinneret. C. magellanicus sp. n. can be separated from the ot her species of the genus by the following combination of characters: b ody length (1.7-2.1 mm), buccal cavity size (32-36 X 18-22 mu m), apex of the dorsal tooth at 76-80 % of the total buccal cavity from base, spicule length (97-98 mu m), not very slender lateral guiding pieces, conoid and ventrally arcuate rail with broadly rounded terminus, and a bsence of caudal glands. (C) Orstom/Elsevier, Paris.