Chernyshevia, Sagorny & Döhren & Rouse & Tilic, 2022

Sagorny, Christina, Döhren, Jörn von, Rouse, Greg W. & Tilic, Ekin, 2022, Cutting the ribbon: bathyal Nemertea from seeps along the Costa Rica margin, with descriptions of 2 new genera and 9 new species, European Journal of Taxonomy 845 (1), pp. 132-174 : 147-149

Genus Chernyshevia gen. nov.

urn:lsid:zoobank.org:act:BFBBBA9E-80F4-4F57-9A81-B85FE723A7A6

Type species

Chernyshevia escarpiaphila gen. et sp. nov.

Diagnosis

Monostiliferan nemertean lacking eyes, with one pair of ventro-lateral cephalic furrows continuing as unforked ciliated canal; cerebral organs close in front of brain; rhynchocoel extending to posterior end of body; apical organ present; cephalic glands extending to brain; lateral nerve cords with small accessory nerves; mid-dorsal blood vessel without vascular plug; intestinal cecum with anterior diverticula; sexes separate.

Etymology

The genus is named after Dr Alexei Chernyshev to acknowledge his significant contributions to the study of deep-sea nemerteans.

Phylogenetic remarks

The genus is sister to the represented specimen of Tetrastemma elegans (Girard, 1852) ( Fig. 7 ) that is in need of revision. This clade is sister to the monotypic genus Vieitezia Junoy, Andrade & Giribet, 2010 , including specimens of the type species Vieitezia luzmurubeae Junoy, Andrade & Giribet, 2010 , and specimens of Tetrastemma vittigerum ( Bürger, 1904) . The genus is nested within a clade that also includes the new genus Alvinonemertes gen. nov., as well as the represented specimens of the genera Gononemertes Bergendal, 1900 and Galathenemertes Chernyshev & Polyakova, 2019 ( Fig. 7 ).

Remarks

The genus Chernyshevia gen. nov. is erected as new genus based on its phylogenetic position and the questionable position of different species of ‘ Tetrastemma ’ ( T. elegans and T. vittigerum ) that are nested within the same clade as Chernyshevia . Moreover, some morphological differences between specimens of the genera Vieitezia and Chernyshevia , such as the absence or presence of an accessory nerve, the dimension of the cephalic glands, and the presence of separate sexes, might also support the presence of a new genus.

Species included

Only the type species Chernyshevia escarpiaphila gen. et. sp. nov.

Figures

Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.