Freeliving nematodes from nature reserves in Costa Rica. 1. Dorylaimina

This article gives the first results of a study of dorylaims found in nature reserves in Costa Rica. The material examined shows the great interest of the nematofauna of these reserves. Two species were found for which new generic names had to be erected: Parapalus n.gen. for a species resembling Paraxonchium but with a long symmetrical odontostyle as in Gopalus the single species P. arboricola n.sp. lives in epiphytic mosses. Inbionema n.gen. is conspicuous for the very widely separate lips and the long (but not needle-shaped) odontostyle; the single species I. biforme n.sp, (named because there are two classes of odontostyle length, under 44 and over 59 mum) lives in the same habitat as the previous species. Other new species found are: Pachydorylaimus schizodontus n.sp. (furcate part eel 33% of odontostyle length), Sicorinema esquiveli n.sp. (cuticular annules 0.5 Crm wide, body length over 1 mm): Brasilaimus bidentatus n.sp. (24-26 longitudinal ridges, each onchium with an additional denticle), B. vinciguerrae n.sp. (32 ridges, odontostyle slender), Xiphinemella monyhystera n.sp. (female monodelphic, tail conoid in both sexes) and Tyleptus bongersi n.sp. (liplets amalgamated into disc-like structure, distance vulva-cardia very short). The female of Idiodorylaimus annulatus (von Daday, 1905) is reported for the first time. The following nominal species were found and redescribed: Practinocephalus secundus Andrassy, 1986, Axonchium labiatum Thorne, 1939, Metaxonchium micans (Thorne, 1939), Oxydirus tropicus Theme, 1964, O. tenuicaudatus Theme, 1964, Funaria acuta (Zullini, 1973), Caveonchus saccutus (Goseco et al., 1981) and Sclerostylus xiphinemoides (Monteiro, 1970). A key to the species of Pachydorylaimus is given. The subfamily Paraxonchiinae and the position of the genus Gopalus are discussed