A new genus and two new species of cavernicolous amphipods (Crustacea: Typhlogammaridae) from the Western Caucasus

Abstract

Abstract. This study deals with the biodiversity and distribution of cavernicolous Amphipoda in caves of the Arabika massif (Western Caucasus). The Sarma, Trojka and Orlinoe Gnezdo caves were explored during speleological expeditions over the years 2011-12. Two new species of Amphipoda were found: a sub-surface dweller Zenkevitchia sandroruffoi sp. nov. is reported from the Sarma, Trojka and Orlinoe Gnezdo caves at depths from -30 m to -350 m; the second one, a deep dweller Adaugammarus pilosus gen. et sp. nov. is reported from the Sarma Cave at depths of -1270 to -1700 m. Adaugammarus gen. nov. shares similarities with Typhlogammarus Schäferna, 1907 and Zenkevitchia Birstein, 1940. The species Anopogammarus birsteini Derzhavin, 1945 is also re-described herein based on new samples that suggest close affinity of this species with the family Gammaridae. The original taxonomic combination is resurrected for Zenkevitchia revazi Birstein & Ljovuschkin, 1970, comb. resurr. (from Anopogammarus Derzhavin, 1945. To accommodate morphologically different species in the genus Zenkevitchia, two new groups are proposed. These are the admirabilis-group (Z. admirabilis Birstein, 1940 and Z. yakovi Sidorov, 2015) and the sandroruffoi-group (Z. sandroruffoi sp. nov. and Z. revazi). An updated molecular (mt-cox1) phylogeny, an identification key to the genera and a distribution map for the typhlogammarid amphipod species of Transcaucasia are provided.

Kruberia abchasica, a new genus and species of troglobiont amphipods (Crustacea: Gammaridae) from Krubera Cave (Western Transcaucasia)

“…However, Anopogammarus differs in asymmetric palp of maxilla I and in two-segmented exopodite of uropod III. A typical species of the genus Adaugammarus -A. pilosus [see Sidorov et al, 2015] and in species of the genus Typhlogammarus has a different structure of the front edge of the head with recess; also, these genera is different in the shape of basipodite of pereopods V-VII and uropod III. From the sandroruffoi-group (Zenkevitchia) it differs in short antennal cone of antenna II, not reduced palp of maxilla I and in large predatory gnathopod propodi.…”

“…The taxonomic richness of underground gammarids of Western Transcaucasia is not very diverse. In partic-ular for Abkhazia only 3 stygobiont genera of Gammaridae Leach, 1814 and Typhlogammaridae Bousfield, 1978 families are known [see Birstein, 1940;Derzhavin, 1945;Sidorov et al, 2015]; two of them -Anopogammarus Derzhavin, 1945 and Adaugammarus Sidorov, Gontcharov et Sharina, 2015 each represented by the single species, whereas from the genus Zenkevitchia Birstein, 1940 four species are known.…”

Zenkevitchia Karamani, a Distinct New Species of Admirabilis-Group (Crustacea: Amphipoda: Typhlogammaridae) From Abkhazia

“…n. is an unique taxon that shares the features of several groups. Among the seven subterranean species of gammarid Amphipoda of the Caucasian region (Anopogammarus birsteini Derzhavin, 1945, Kruberia abchasica Sidorov, Samokhin, in press) in Gammaridae and (Adaugammarus pilosus Sidorov et al, 2015, Zenkevitchia admirabilis, Zenkevitchia sandroruffoi Sidorov et al, 2015, Zenkevitchia revazi Birstein et Ljovuschkin, 1970, Zenkevitchia yakovi Sidorov, 2015 in Typhlogammaridae, Z. karamani has a some distinct features: (1) palmar angle of gnathopods with small corner spines on inner face (this feature is also inherent to the following species A. birsteini, K. abchasica and A. pilosus); (2) modified spine between lacinia and molar process (this feature is also inherent to K. abchasica) (Sidorov, Samokhin, in press).…”

“…The endemial cavernicolous genus Zenkevitchia was established by Birstein (1940), based primarily on morphology of the outer plate of maxilla 1, which was described as ‗filtrative' with numerous multitoothed spines. To date four species of Zenkevitchia have been reported from the Abkhazian caves, which are preliminarily attributed in two unranked categories ‗admirabilis' and ‗sandroruffoi' groups (Sidorov et al, 2015).…”

Crustacean “cave fishes” from the Arabika karst massif (Abkhazia, Western Caucasus): new species of stygobiotic crustacean genera Xiphocaridinella and Niphargus from the Gegskaya Cave and adjacent area

“…Unfortunately, scientists have never collected or researched samples of such mysterious Caucasian cave fishes. At the same time, it is known that a unique endemic fauna lives in the Arabika karst massif [e.g., Sidorov, 2014;Sidorov et al, 2015Sidorov et al, , 2018Sidorov, Samokhin, 2016] and some interesting animals are expected to be discovered from there.…”