The Genus Xiphinema (Dorylaimida) in Surinam

Abstract

Investigation of the Xiphinema material collected in Surinam by den Ouden in 1964 and by Maas in 1965-1970 showed six species to occur, four of which are new. X. filicaudatum n. sp. is characterized by a spear length of 300 μ or more and by its very long filiform tail. X. surinamense n. sp., which occurs in a smaller and a larger form, is a round-tailed species, with males having only one mid-ventral supplement. In both species only the posterior female gonad is functional; the uterus of the anterior gonad is identical in size and structure to that of the posterior one, but the anterior ovary and oviduct are lacking. In X. denoudeni n. sp. the anterior gonad is more strongly reduced; tail shape varies from convex-conoid to digitate; males are unknown. X. imambaksi n. sp., of which also only females were found, is a didelphic species possessing a Z-organ; the tail is digitate. The other two species found are X. elongatum Schuurmans Stekhoven & Teunissen, 1938 and X. vulgare Tarjan, 1964. It is recommended that, in species descriptions in this genus, great attention be given to the structure of the female reproductive system. The hypothesis is put forward that the odontostyle-forming cell does not stop its activity at the same moment of ontogeny in all specimens; this would explain that within one species one may find adults with mucro, without mucro and with a complete extra odontostyle. Attention is drawn to intraspecific variation in Xiphinema species. Finally a key is given.