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The article presents a study on the nature and phylogenetic vulval appendages in nematodes. The phylogenetic distribution of nematode vulval appendages showed three major classes which include cuticular inflations, protruding vulvar appendages of extruded gonadal tissues and vulval ridges. The study found vulval appendages in commensal or parasitic nematode taxa. The evaluation of vulval appendages in nematode taxonomy requires accurate definitions, terminology and documentation.

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. [ABSTRACT FROM AUTHOR]

Three species of nematodes from the nematofauna found in Spanish fir woodlands (pinsapo forests) are described: Prodesmodora zullinii n. sp., Prodesmodora nigra n. sp. and Chiloplectus loricatus Andrássy, 1985. P. zullinii n. sp. is a relatively small species of this genus, has a variable body length (0.25-0.41 mm), only two denticles on the stoma wall, amphid diam. 25-40% of the corresponding body diam., located at 12.1± 1.2 μm of the anterior end, vulva-anus distance 2-2.3 times the tail length, vaginal wall lightly sclerotised and tail tip pointed. P.nigra n. sp., also a relatively small species (0.53-0.55 mm), is characterised by three denticles on the stoma wall, amphid diam. 30-34% of the corresponding body diam. situated at 17.6 ± 0.9 μm of the anterior end, and vulva-anus distance 2.7-2.9 times the tail length, vaginal sclerotisation wall prominent and tail tip pointed. Two additional differential characters for C. loricatus are the seven to ten rows of denticles of the pharynx valve and two small projections on both sides of the spinneret base. Data are presented on some ecological features of the habitat where these three species were found, as well as taxonomic data comparing the different species of Prodesmodora smaller than 0.55 mm. [ABSTRACT FROM AUTHOR]

Nematode communities of 18 Indiana mixed hardwood stands were comprised of an average of 23% tylenchid species, 31% dorylaimid species, and 46% species of six other orders. Based on total numbers of individuals present the stands averaged 42% tylenchids, 20% dorylaimids, and 38% individuals of other orders. Ordination of the sites using data only for tylenchid species gave an even distribution of sites, indicating little effect of site disturbances on tylenchid populations. By contrast an ordination using data for dorylaimid species showed a high degree ofd issimilarity between reference sites indicating that disturbances at some sites had drastically affected the dorylaimid fauna. An ordination utilizing biomass of all species present was very similar to the ordination based on data for dorylaimid species only.