DESCRIPTION OF HEMICRICONEMOIDES-PARATAIWANENSIS SP-N (CRICONEMATIDAE) AND 4 OTHER HEMICRICONEMOIDES SPECIES FROM PAPUA-NEW-GUINEA WITH A CONSIDERATION OF VARIABILITY IN THE GENUS

Hemicriconemoides populations from Papua New Guinea contained H. parataiwanensis sp. n. (differing from H. taiwanensis in head shape, stylet length and RVan value), H. mangiferae, H. cocophillus, H. gaddi and H. obtusus. H. mangiferae was represented by two populations, so different from each other that their inclusion in the same species could only be concluded after comparison with some twenty populations from the literature. This study of variability demonstrated that the number of body annuli is correlated to body length, suggesting that annulus width is constant in Hemicriconemoides species; other correlations found are between number of body annuli and stylet length and between body annuli and vulva position. SEM study of the en face view revealed four different types of head structure: the most common one shows a narrow oral disc and two large, but covered, amphidial openings; a second type shows a large raised oral disc with an outer rim with amphids sometimes indistinct; while third and fourth types are represented only by one Australian species each.