Prochaetosoma Micoletzky, 1922

Fedyaeva, Maria A., Neretina, Tatjana V., Konovalova, Olga P. & Tchesunov, Alexei V., 2016, Two known and one new species of Draconematidae and Epsilonematidae (Nematoda, Desmodorida) from the White Sea, North Russia, Zootaxa 4121 (4), pp. 383-411 : 393

Genus Prochaetosoma Micoletzky, 1922

Diagnosis (after Allen & Noffsinger 1978; Decraemer et al. 1997, emended): Prochaetosomatinae . Pharyngeal body region only slightly swollen. Rostrum rounded. Six to 14 CATs located just posterior to rostrum. Amphideal fovea loop-shaped to uni- or doubled spiral. PATs all anterior to anus. Pharynx consists of cylindrical corpus and posterior bulb; internal cuticle of the bulb distinctly thickened in most species. Buccal cavity with conspicuous dorsal tooth.

Type species: Prochaetosoma primitiva ( Steiner, 1916) Micoletzky, 1922 .

Discussion. In their synthesis of Draconematidae, Decraemer et al. (1997) listed ten species of Prochaetosoma . Some of these species, i.e. P. arcticum ( Kreis, 1963) , D. lugubre ( Gerlach, 1957) and P. primitivum ( Steiner, 1916) are known from only a few or a single female and juveniles. The lack of males in the original diagnoses hampers identification because the males, apart from the copulatory apparatus important for species determination, may possess particular precloacal midventral differentiations indicating belonging to a definite species. Therefore, since diagnoses of P. arcticum and P. lugubre miss male characters, and their females are not marked by any clear diagnostic features, both these species are qualified here as species inquirendae. They may be restored as valid species in future if males and females found and re-described from type localities. Decraemer et al. (1997) regarded P. primitivum , the type species of Prochaetosoma Micoletzky, 1922 , despite the lack of males, since the single fourth stage juvenile specimen described distinctive characters such as the number of posterior adhesive tubes.

Rho et al. (2010) described P. dokdoense , summarized eleven valid species of Prochaetosoma and provided a table and a key for their identification. Almost simultaneously, Rho & Min (2011) described eight additional species ( P. beomseomense Rho & Kim , P. brevicaudatum Rho & Kim , P. byungilli Rho & Kim , P. cracense Rho & Kim , P. saheungi Rho & Kim , P. sujungi Rho & Kim , P. supseomense Rho & Kim , P. youngdeokense Rho & Kim ). As in the case of Draconema (see above), these species names are accompanied neither with designation of new species nor indication of a former publication of the species. Again, we treat these eight species as invalid.