Zenkevitchia sandroruffoi, Sidorov & Gontcharov & Sharina, 2015

Sidorov, Dmitry A., Gontcharov, Andrey A. & Sharina, Svetlana N., 2015, A new genus and two new species of cavernicolous amphipods (Crustacea: Typhlogammaridae) from the Western Caucasus, European Journal of Taxonomy 168, pp. 1-32 : 11

sandroruffoi -group

Remarks

Although, as described below, Zenkevitchia sandroruffoi sp. nov. differs from other species of Zenkevitchia ( Z. admirabilis , Z. yakovi ) in the non-filtrative maxilla 1, we decided that it, along with Z. revazi , differs sufficiently to warrant recognition as a new species group within the genus Zenkevitchia , which we here designate as the sandroruffoi -group. The sandroruffoi -group ( Z. sandroruffoi sp. nov. and Z. revazi Birstein & Ljovuschkin, 1970 ) is phenotypically more distant from the type species of the genus Zenkevitchia , bearing only up to 22 multi-toothed spines (non-falcate in shape). In some sense, the group occupies an intermediate position between Zenkevitchia ( admirabilis -group) and other species of the Typhlogammaridae (cf. Accubogammarus ), although, in our opinion, it is closer to the former. The indicators for affinity to Zenkevitchia are: interantennal cephalic lobes sub-acute, urosomal segments weakly armed, shortened antenna 1, antennal gland cone of antenna 2 long, reduced and subsymmetrical palps of maxilla 1, structure and armament of gnathopods (both appendages with well-defined palmar angle).

Despite these points of similarity, Z. revazi needs re-description because some features, such as sexual dimorphism, were not described properly, although important characters that clearly differentiate both species (characteristics of Z. sandroruffoi sp. nov. in parentheses in the following list) are evident. These are: outer plate of maxilla 1 with 11 spines (22 spines), palps of maxilla 1 asymmetric, reduced (sub-symmetric, cf. Typhlogammarus m. mrazeki Schäferna, 1907 and T. m. heteropalpus Karaman, 1972; Karaman 1972, 1988) body of mandibles compacted (elongated), bases of pereopods 5–7 without lobes (with extraordinary roundish postero-proximal lobes), uropod 3 well-developed, setose with plumose setae (reduced, weakly setose). Zenkevitchia revazi reveals a number of features in common with Accubogammarus and the minor differences between these taxa ( Karaman 1973, 1974, 1988) are mainly related to the structure of uropod 3.