Description of a new species of Epacanthion (Thoracostomopsidae, Nematoda) from Brazil and a modified key for species identification

Abstract

Epacanthion agubernaculus sp. nov. (Thoracostomopsidae, Nematoda) is described from sediments of Campos Basin, Atlantic Southeast, Brazil. The main features are: the long spicules, the absence of gubernaculum, and the presence of three pairs of setae in the tail region. Only one male was found for description, but the main features are strong enough to consider it clearly as a new species. An updated and modified key for species identification is proposed.

New species ofEpacanthion(Nematoda: Thoracostomopsidae) from Patagonia coast, Río Negro and Chubut, Argentina

“…Depending on the length of the spicules, the species of Epacanthion can be classified in two main groups. One with species with long spicules, more than 2 anal diameters, which includes: E. agubernaculus Guilherme et al , 2009; E. brevispiculosum Mawson, 1958; E. bütschlii (Southern, 1914); E. durapelle (Kreis, 1929); E. microdentatus Wieser, 1953; E. nadjae Sergeeva, 1974; E. polysetosum (Jensen, 1986); E. saveljevi (Filipjev, 1927); and E. stekhoveni Greenslade & Nicholas, 1991. And the other with species with short spicules, less than 2 anal diameters, which includes: E. brevispiculum Mawson, 1956; E. enoploidiforme (Gerlach, 1953); E. exploratoris Greenslade & Nicholas, 1991; E. galeatum Boucher, 1977; E. georgei Inglis, 1971; E. gorgonocephalum Warwick, 1970; E. macrolaimus Gagarin, 2009; E. mawsoni Warwick, 1977; E. multipapillatum (Wieser, 1959); E. oliffi Inglis, 1966; E. oweni Keppner, 1986; and E. pellucidum (Saveljev, 1912).…”

“…The last key for Epacanthion is from Guilherme et al (2009), that is a modified version of that present in Greenslade & Nicholas (1991). We modified here a part of that key to add our two new species and E. macrolaimus Gagarin, 2009.…”

“…Epacanthion ampullatum sp. nov. differs with: E. agubernaculus Guilherme et al, 2009 by the presence of gubernaculums; E. multipapillatum (Wieser, 1959), E. oweni Keppner, 1986 by the presence of one pre-cloacal supplement; E. pellucidum (Saveljev, 1912) (Gerlach, 1953), E. georgei Inglis, 1971, E. gorgonocephalum Warwick, 1970, E. oliffi Inglis, 1966 by the presence of pre-cloacal supplement; E. mawsoni Warwick, 1977 by the length of the body, the shape of the tail and the distance pre-cloacal supplement-cloaca; E. polysetosum (Jensen, 1986) by the distance pre-cloacal supplement-cloaca; E. nadjae Sergeeva ,1974, E. saveljevi (Filipjev, 1927 by the length of the spicule (equal length) and E. stekhoveni Greenslade & Nicholas, 1991 by the ausence of setae sparse (only two medial setae) in the tail.…”

“…They established 21 species as belonging to it. Afterwards, Gagarin (2009) has described one new species ( E. macrolaimus ) from the Mediterranean Sea and Guilherme et al (2009) have described another one ( E. agubernaculus ) from Brazil. In this last work, a new key for species identification was proposed.…”