Deltanema Kreis, 1929

Venekey, Virag, Gheller, Paula F., Kandratavicius, Noelia, Cunha, Beatriz Pereira, Vilas-Boas, Ana Carolina, Fonseca, Gustavo & Maria, Tatiana F., 2019, The state of the art of Chromadoridae (Nematoda, Chromadorida): a historical review, diagnoses and comments about valid and dubious genera and a list of valid species, Zootaxa 4578 (1), pp. 1-67 : 51-52

Genus Deltanema Kreis, 1929

The genus Deltanema was described by Kreis (1929) in subfamily Desmodorinae Filipjev, 1922 (at that time this subfamily belonged to Chromadoridae ), based on a single female, when he found the new species D. parvum Kreis, 1929 in the English Channel. Kreis (1929) argued that Deltanema is close to Chromadorina and Chromadorita but distinguished from these genera by the well-developed teeth. Hope & Murphy (1972) synonymized Deltanema with Metalinhomoeus but nevertheless Lorenzen (1994) recognized it as a valid genus in Hypodontolaiminae . Smol & Decraemer (2006) and Tchesunov (2014) argued that Deltanema has limited description and poor illustrations, therefore it should be considered a dubious genus. We agree with them and also consider Deltanema here as a dubious genus.

Genus Deltanema Kreis, 1929

1. Deltanema parvum Kreis, 1929 (English Channel)

Genus Dicriconema Steiner & Hoeppli, 1926

The genus Dicriconema is known from a single species, Dicriconema tenuis Steiner & Hoeppli, 1926 ; described based on a single immature female. Steiner & Hoeppli (1926) described the cuticle in details but gave little information about internal organs stating that they are unable to complete the generic diagnosis due to the thick cuticle which obscured the internal structures. Wieser (1954) regarded Dicriconema as a dubious genus considering it closely related to Euchromadora , distinguishable only by some differences in the cuticle. Inglis (1969) reviewed Euchromadora and similar genera comparing cuticle and other characters. The author considered D. tenuis as species inquirenda stating that Dicriconema cannot be unequivocably recognized. Nevertheless, both Gerlach & Riemann (1973) and Lorenzen (1994) considered it as valid genus of Euchromadorinae without any discussion. Kulikov & Dashchenko (1991) presented an identification key to genera of Euchromadorinae and considered Dicriconema as dubious using the same argumentation as Inglis (1969). More recently Tchesunov (2014) omitted Dicriconema without any explanation and we consider it invalid based on Inglis (1969) and Kulikov & Dashchenko (1991).

Genus Dicriconema Steiner & Hoeppli, 1926

1. Dicriconema tenue Steiner & Hoeppli, 1926 ( Japan, Pacific Coast)