Dursogammarus dromaderus Marin & Palatov, 2022

Marin, Ivan, Palatov, Dmitry & Copilaș-Ciocianu, Denis, 2023, The remarkable Ponto-Caspian amphipod diversity of the lower Durso River (SW Caucasus) with the description of Litorogammarus dursi gen. et sp. nov., Zootaxa 5297 (4), pp. 483-517 : 512

Dursogammarus dromaderus Marin & Palatov, 2022

Figs 19–20

Dursogammarus dromaderus Marin & Palatov, 2022: 3 , figs 1–4 [type locality— Durso , Russia].

Material examined. 4 ÔÔ, LEMMI — Russian Federation, southwestern Caucasus, Krasnodar Krai, Novorossiysk area, mouth of Durso river , 44°40’42.7”N 37°33’41.9”E, in the stream under stones and boulders, with hand net, coll. Palatov D.M. & Marin I.N., 20.07.2021 .

Diagnosis. Hea d with blunt lateral lobes. Pleon with free smooth urosomites and well-defined remarkable conical protrusion (knob) on dorsal surface of urosomal segment I. Antenna I with 3-segmented accessory flagellum. Antenna II with calceoli on articles I – X. Gnathopod I with teardrop-shaped propodus (palm). Gnathopod II with pyriform propodus (palm), with oblique distoventral part of palmar margin. Pleopods with 2 elongated hooks and 2 thick bristles in retinacules. Pereopod VII with basis (article 2) lacking ventral lobe. Uropod III with outer ramus broad, about 5–6 times as long as wide, with mostly reduced distal article.

Remarks. For the morphology see the original description of the species ( Marin & Palatov, 2022). However, Figures 3–4 , presented in the original description, were accidentally published incorrectly (see Marin & Palatov, 2022). Herewith we presented the correct one showing epimeral plates, telson, pleopods and the structure of the retinacula, the dorsal knob on urosomal segment I and uropods ( Figs. 19 , 20 ).

Dursogammarus dromaderus is similar to Gmelina G.O. Sars, 1894 in having a slender body and a long uropod III. The presence and the form of the dorsal knob of urosomal segment I are rather unique features within the Ponto-Caspian gammarids as well as the family Gammaridae , which clearly identified the species. Moreover, the phylogenetic analyses revealed that the genus is not closely related to the Caucasian Ponto-Caspian gammarids, instead being nested within the Atlantic-Mediterranean Pectenogammarus clade (see Fig. 3 ).

GenBank accession number. OQ407695 (this study).

Distribution and ecology. The species is presently known from the lower part of the Durso River, living under a thick layer of pebble, very close to the sea.

Figures

FIGURE 3. Maximum-likelihood phylogenetic tree based on COI. Number above nodes represent ultrafast bootstrap (UFBS) and Shimodaira-Hasegawa approximate likelihood ratio test (SHaLRT) values. Number below nodes represent posterior probabilities (PP). Strongly supported nodes in all analyses are shown with green circles. Species from Durso River are indicated with red arrows. Taxonomically relevant taxa are shown with various colors. Species belonging to Chaetogammarus are shown with dotted branches.

FIGURE 4. Litorogammarus dursi sp. nov., holotype Ô, ZMMU Mb-1243 (a–c, e, f, i, j), paratype ♀, ZMMU Mb-1244 (d, g, h, k, l): a—antenna I; b—accessory flagellum of antenna I; c, d—antenna II; e, g—gnathopod I; f, h—palmar margin of chela of GnI; i, k—gnathopod II; j, l—palmar margin of chela of GnII.

FIGURE 19. Dursogammarus dromaderus Marin & Palatov, 2022, holotype Ô, ZMMU Mb-1225: a–c—epimeral plates I–III; d—telson; e—urosomal segment I with dorsal knob; f—pleopod III; g—retinacula of pleopod III; h—uropod I; i—uropod II; j—uropod III; k—distal segment of outer ramus (exopod) of uropod III.

FIGURE 20. Dursogammarus dromaderus Marin & Palatov, 2022, Ô (LEMMI), urosomal segments, lateral view, and dorsal knob of urosomal segment I (enlarged).