Free-living nematodes from nature reserves in Costa Rica. 3. Araeolaimida

Seven species of Araeolaimida were found in soil, moss and freshwater habitats of tropical forests in Costa Rica. Three are described as new. Anonchus pulcher n. sp. is characterised by slender body, lip region demarcated by a depression, presence of ca 45-60 sublateral glands on each side of the body and monoprodelphic female genital apparatus. Paraplectonema americanum n. sp. lacks somatic setae, the stoma is 3.0-3.4 lip region diameter long, the female rectum measures 26 μm, the male tail 137-153 μm, presence of ten to 11 male supplements, spicula 28-30 μm long, gubernaculum of complicated shape with a caudal apophysis. Chronogaster costaricae n. sp. is characterised by absence of longitudinal incisures, rows of spines, crystalloids and vacuolated glandular bodies, terminus with open mucro with one or two basal spines. The species redescribed, either briefly for well known, or more extensively for less well known, species are: Plectus patagonicus de Man, 1904; P. indicus Khera, 1972; Chronogaster serrulata Loof, 1973 and C. cameroonensis Heyns & Coomans, 1984