Paramysis (Paramysis) baeri Czerniavsky, 1882

Daneliya, Mikhail E., Audzijonyte, Asta & Väinölä, Risto, 2007, Diversity within the Ponto-Caspian Paramysis baeri Czerniavsky sensu lato revisited: P. bakuensis G. O. Sars restored (Crustacea: Mysida: Mysidae), Zootaxa 1632, pp. 21-36 : 24-29

Paramysis (Paramysis) baeri Czerniavsky, 1882

( Figs 2–5 )

Paramysis baeri Czerniavsky, 1882: 56 partim; Sars 1893: 403, pl. I, II; 1907: 256, 293 Paramysis (s. str.) baeri Derzhavin 1939: 37 partim

Paramysis (Paramysis) baeri Daneliya 2004: 409 partim

Paramysis baeri s. str. Audzijonyte et al. 2006: 2974.

Type specimens. Lectotype (+slide), subadult ɗ, 22.5 mm, “Baer, Kaspiiskoe more” ( ZIN, 2631). Paralectotype, Ψ, 24.5 mm, “Baer, Kaspiiskoe more” ( ZIN, 1/88426). The type series of P. baeri Czerniavsky, 1882 included five specimens, of which two we designated as the lectotype and paralectotype while three others (two ɗ and one Ψ) were identified as P. b a k u e n s i s and therefore excluded from the type series ( ZIN, 1/88427). The description of Czerniavsky (1882) also refers to additional material that was not assigned a type status. These are: P.(P.) b a e r i: 9 ɗ, 2 Ψ, 28 juveniles, “Goebel, Kaspiiskoe more, port Astara, 18 m, 24.08.1863 ” (Southern Caspian Sea) ( ZIN, 2633); 2 ɗ, 1 Ψ, “Baer, Kaspiiskoe more, Mangyshlak” (Northern Caspian Sea) ( ZIN, 2632) [from the same sample 6 ɗ, 6 Ψ, 1 juvenile identified as P. (P.) b a k u e n s i s ( ZIN, 2/88428)]; 1 ɗ, “Goebel, Kaspiiskoe more, 1863» ( ZIN, 2663). Specimens from the Caspian Sea (Baku), which Czerniavsky (1882, p. 62) designated as Paramysis baeri varietas littoralis and deposited in the Zoological Museum of Odessa University, have been lost, and their identity cannot be established.

Type locality. Caspian Sea.

Additional material. ɗ and Ψ, Volga delta, Kharbuta ilmen, 45°41´39´´ N, 47°25´18´´ E, 4–5 feet (~ 1.5 m), mud, 19.06.1904, “Strazha” ( ZIN, 5193); 20 ɗ and 9 Ψ, Volga delta, Kharbuta ilmen, 45°40´35´´ N, 47°30´15´´ E, st. 110, N416, about 5/ 3 m, mud, 19.06.1904, “Strazha” ( ZIN); ɗ, st. 110, G.O. Sars ( ZMO, F12166); 9 ɗ, 7 Ψ, 1 juvenile, Caspian Sea, st. 110, N416 ( ZMO, F19746); ɗ (+ slide), G.O. Sars ( ZMO, F12165); 2 ɗ, 1 Ψ, Caspian Sea, st. 15, Warpachowsky ( ZMO, F19739); Ψ, Caspian Sea, Lonberg ( ZMO, F19747); 21 ɗ and 43 Ψ, Caspian Sea, Agrakhan Bay, 0 6.08.1921, Rustambekova ( ZIN); fragment, Caspian Sea, 43°11´N, 51°17´22´´ E, by Cape Peshchanyi, st. 69, N291, 10 m, sand+shells, 23.05.1904, “Geok-Tepe” ( ZIN, 5691); Ψ, Caspian Sea, 45°09´N, 49°50´30´´ E, st. 19, N74, 9 m, sand+shells, 29– 30.03.1904, “Geok- Tepe” ( ZIN, 5686); ɗ and juvenile, Kaspiske Hav (Caspian Sea) ( ZMUC, CRU- 9900); ɗ (slide), G.O. Sars ( NHMUO, F12165); 1 juvenile, Kaspisch. Meer (Caspian Sea) ( ZMB, 11286); 13 ɗ and 21 Ψ, Caspian Sea, Dagestan, by Krainovka, shells+mud, 2–4 m, 0 2.05.2004, Audzijonyte ( MZH, 53002; GenBank DQ779856 , DQ779857 ); 2 ɗ (+5 slides of ɗ) and 7 Ψ (+6 slides of Ψ), Caspian Sea, Dagestan, Sulak Bay, from Sulak River mouth to the sea, mud+sand, 4–8 m, 0 1.05.2004, Audzijonyte ( MZH, 53001; GenBank DQ779858 , DQ779859 , DQ779860 ); 4 juveniles, Caspian Sea, Dagestan, by Sulak mouth, mud, 8–10 m, 0 3.05.2004, Audzijonyte ( MZH, 53026); ɗ, Caspian Sea, Dagestan, Staroterkskoe, canal, plants, mud, 0 2.05.2004, Audzijonyte ( MZH, 53010); 2 ɗ, Caspian Sea, Dagestan, Audzijonyte ( MZH, 53004).

Revised description. Body slender; body length (from tip of subrostral lamina to end of telson) of mature males 13–25 mm, mature females 15–31 mm. Head about as wide as 1st abdominal segment. Subrostral lamina rather long, distinctly protrudes from under the carapace. Carapace: frontal margin convex, smoothly rounded; antero-lateral angles acute; distal margin does not cover the last thoracic segment. Telson longer than the last abdominal segment, tapering distally, 2.1–2.6 times wider proximally than distally; length 2.3–2.5 times the proximal width; cleft small, acute- or right-angled, with 3–11 denticles; lateral margins with 16–23 spine-setae and fine setae.

Eyes large, pyriform. Antennular peduncle only slightly shorter than antennal peduncle. Male antennular process large, larger than 3rd segment of antennular peduncle. Antennal scale about twice as long as the antennular peduncle, lanceolate, with a strong outer spine-seta; inner and frontal margins with long setae; frontal margin narrow and almost straight; distal width less than 0.55 of the maximal width (from outer side of base of the spine-seta till outer side of distal segment of the scale); spine-seta advances beyond the distal margin; length 3.1–3.5 times the maximal width.

Upper labrum smooth, convex. Mandibular palp: 2nd segment 1.7–1.8 times as long as 3rd segment; ventral setae of the 2nd segment quite long, densely set. Maxilla II: exopod rather wide, almost square, width up to 1.3 times the length, with long proximal and short distal setae; proximal setae protrude from the lateral sides of the carapace near pleurocervical fissures; second segment of endopod with setae and one to three frontal spine-setae.

Maxillipede I: exopod with 9 segments; preischium endite and ischium endite well-developed; ischium endite larger than the preischium endite; merus length 1.7 times its width. Maxillipede II: exopod with 10 segments; ischium length 1.4–1.7 times its width; merus length 2.0–2.2 times its width; merus length 1.1 times ischium length; carpopropodus 2.0–2.5 times as long as dactylus; dactylar dorsal setae strong, claw-like, strongly serrated; dactylar ventral setae about twice as long as dorsal claw-setae; terminal dactylar claw-setae strongly serrated.

Pereiopods: exopod with 9–10 segments; merus of endopod 0.7–0.8 times as long as ischium; carpopropodus with four segments; paradactylar claw-setae with wide, strong denticles. Pereiopod I: preischium with one to three setae; dorsal margin of ischium with central and distal groups of setae; ischium length 2.9–3.6 times its width; merus about the same width as ischium and 0.7–0.8 as long as ischium, with five or six bunches of almost straight ventral setae; merus length 2.5–3.1 times its width; 4th segment of carpopropodus 0.6 of the length of 3rd segment; two or three paradactylar claw-setae with denticles; strong dactylar claw-seta smooth. Pereiopod VI: ischium length 2.7–3.2 times its width; one or two paradactylar claw-setae with strong denticles.

Penis with large outer blade and one to three distal long setae; apex with multiple long setae curved inside around gonopore. Pleopods of female reduced, uniramous. Pleopods I, II, V of male reduced, uniramous, pleopod III biramous. Pleopod IV of mature male: endopod reduced, exopod long, with five segments, extends beyond the abdomen, its basis exceeds 6th abdominal segment; 2nd exopod segment the same length as 4th and 5th together; relative lengths of segments 3:2:3.5:1:1. Endopod of uropod with a total of 7–16 spine-setae along one to two thirds of inner margin, with the proximal spine-setae arranged in two rows.

Diagnosis. Telson cleft with 3–11 denticles. Frontal margin of antennal scale narrow and almost straight, distal width less than 0.55 of maximum width. Exopod of maxilla II almost square, wider than long. Pereiopod I merus length three times its width. Paradactylar claw-setae of all pereiopods with strong serration.

P. baeri differs from P. bakuensis by all above-mentioned characters. From P. e u r y l e p i s it differs by the same set of characters and also by narrower antennal scale, which is at least three times as long as wide (less than three times in P. e u r y l e p i s); and by the long proximal and short distal setae of the maxilla II exopod (all setae equally long and protruding from the lateral sides of the carapace near pleurocervical fissures in P. e u r y l e p i s). P. baeri can not be separated from P. k e s s l e r i by the shape of antennal scale, yet it differs by the long proximal setae protruding from the lateral sides of pleurocervical fissures and the short distal setae of maxilla II exopod (all equally short and not protruding in P. kessleri ); it also differs by the length of pereiopod I merus, which is 0.7–0.8 of ischium length (almost equal to ischium in P. kessleri ); by the shorter 4th segment of the carpopropodus, which is slightly more than a half of 3rd segment (0.7 in P. kessleri ); and by spine-setae of uropod endopod that are arranged in two rows proximally (one row in P. kessleri ).

Molecular characters. P. baeri is characterized by a unique mitochondrial DNA lineage typified by the CO1 gene fragment sequence (GenBank DQ779860 ), from which all studied conspecific specimens (N = 4; DQ779856 – DQ779859 ) differ by less than 2.5%, whereas divergence from the closest species P. bakuensis is> 7.2% ( Audzijonyte et al. 2006).

Distribution. Endemic of the Caspian Sea. So far known from the Northern Caspian Sea and western coast of the Central and Southern Caspian Sea (Fig. 1).

Habitat. Upper sublittoral (0–20 m). Fresh and oligohaline waters (0–5‰, rarely up to 13‰). Sandy, sandy-muddy bottom (psammophilic). Recorded together with P. kessleri and P. ullskyi , rarely with P. bakuensis . Evident habitat difference from P. bakuensis has not yet been found, although P. baeri seems to have slightly wider depth range (0–8 m in P. bakuensis ). The two species have been found together at several Caspian Sea stations. Both species inhabit the upper sublittoral, in contrast to P. e u r y l e p i s, detected at depths from 10 to 114 m. P. kessleri in turn is more eurybiotic, found at depths from 0 m to 114 m ( Derzhavin, 1939).

Figures

FIGURE 2. Paramysis baeri Czerniavsky, 1882, lectotype, subadult ♂. Scale 1 mm.

FIGURE 3. Paramysis baeri Czerniavsky, 1882, lectotype, subadult ♂: (a) mandibular palp, medial view; (b) maxilla I, frontal view; (c) maxillipede I, frontal view; (d) maxillipede II, frontal view. Scales 0.5 mm.

FIGURE 4. Paramysis baeri Czerniavsky, 1882, lectotype, subadult ♂: (a) telson; (b) antennal scale (without setae); (c) maxilla II, frontal view; (d) pereiopod I, frontal view; (e) pereiopod VI, frontal view; (f) dactylus of pereiopod VI, frontal view. Scales: (a), (b), (c), (d), (e) 0.5 mm, (f) 0.25 mm.

FIGURE 5. Paramysis baeri Czerniavsky, 1882: (a – c) ♂, Dagestan; (a) head; (b) penis, medial view; (c) pleopod IV, dorsal view; (d) lectotype, subadult ♂, endopod of uropod (without setae and statocyst), ventral view. Scales: (a) 1 mm, (b), (c), (d) 0.5 mm.