Paramysis (Paramysis) bakuensis G.O. Sars, 1895

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 : 30-34

Paramysis (Paramysis) bakuensis G.O. Sars, 1895 , stat. rev.

( Figs 6 , 7 )

Paramysis bakuensis G.O. Sars, 1895: 437 , pl. II, figs. 1–10; Sars 1907: 257, 293; Băcescu 1934: 335; Paramysis baeri Sowinsky 1898: 377 ; Băcescu 1934: 335;

Paramysis (Paramysis) baeri Derzhavin 1939: 37 partim; Daneliya 2004: 409 partim; Paramysis baeri bispinosa Martynov 1924: 61 ; Buchalowa 1929: 237; Pauli 1957: 149; Paramysis (Paramysis) baeri bispinosa Băcescu 1954: 114 , fig. 45; Băcescu 1969: 374; Komarova 1991: 83; Paramysis cf. baeri I Audzijonyte et al. 2006: 2974 ;

Paramysis cf. baeri II Audzijonyte et al. 2006: 2974.

Type specimens. Lectotype (+slide), subadult Ψ, 11 mm, « Paramysis bakuensis G.O. Sars Mysis relicta Sin. Baku 6 fm VI/1874 », Grimm ( ZIN, 5694); paralectotype, subadult ɗ, 9 mm, “ Paramysis bakuensis G.O. Sars Sin. Baku 6 f, Kaspian Sea”, Grimm ( ZMO, F19722).

Type locality. Caspian Sea: Southern Caspian Sea near Baku.

Additional specimens. 3 ɗ and 7 juveniles, Oblast Voiska Donskogo (Don), 0 4.08.1919, Martynov ( ZIN, 6168); Ψ and juveniles, same district, Siniavskaya (Don Delta), 29.05.1920, Martynov ( ZIN, 6162); Ψ, as previous ( ZIN, 6163); 1 ɗ, 3 Ψ and 5 juveniles, same district, 15.08.1920, Martynov ( ZIN, 6164); 2 ɗ and 2 juveniles, same district, Bagaevskaya (Don), 30.07.– 03.08.1919, Martynov ( ZIN, 6165); 7 juveniles, same district, Kuterma (Don delta), 19.06.1920, Martynov ( ZIN, 42/86846); 1 ɗ, 4 Ψ and 3 juveniles, as previous ( ZIN, 11824); juvenile, Don, Rostov-on-Don, 13.07.1913, Derzhavin ( ZIN, 37788); 8 juveniles, Sea of Azov, Mariupol, shoreline, N25, 1– 1.5 m, mud+sand, 0 6.09.1914, Derzhavin ( ZIN, 37791); many, Sea of Azov, Glafirovskaya spit, st. 406a, N2822, 26.10.1924, Derzhavin ( ZIN, 43/86847); juvenile, Sea of Azov, Miusskii liman, 0 2.09.2003, Audzijonyte ( MZH, 53044); 7 juveniles, Kuban delta, Akhtanizovskii liman, 0 3.09.2003, Daneliya ( MZH, 53003; GenBank DQ779867 ); many (+4 slides of ɗ), Sea of Azov, Taganrog Bay, 25.06.1998, Syrovatka ( ZMRSU, slides in MZH), 3 ɗ and Ψ (+6 slides of ɗ, 5 slides of Ψ), Sea of Azov, Taganrog Bay, Morskaya, mud+sand, 1.5 m, 0 1.07.2001, Daneliya ( MZH, 53043); 2 ɗ, Don, by mouth, 24.06.1999, Syrovatka ( ZMRSU); 3 juveniles, Don Delta, Mertvyi Donets, 13.09.2003, Daneliya ( MZH, 53045; GenBank DQ779865 , DQ779866 ); many adults, Lower Don, Arpachin, 0 3.07.2001, Daneliya ( ZMRSU); 2 Ψ, Lower Don, Razdorskaya, sand, 18.06.1999, Syrovatka ( ZMRSU); 2 Ψ, Lower Don, Bagaevskaya, sand, 19.06.1999, Syrovatka ( ZMRSU); 3 Ψ, same location, 17.05.2000, Daneliya ( ZMRSU); 2 ɗ, 2 Ψ, same location, 0 5.07.2001, Daneliya ( MZH, 53046); Ψ, Lower Don, by Sal River mouth, mud+sand, 17.05.2000, Daneliya ( ZMRSU); Ψ and 16 juveniles, Middle Don, Novogrigorevskaya, sand, 20.08.2000, Daneliya ( ZMRSU); Ψ, Middle Don, Veshenskaya, sand, 26.08.2000, Daneliya ( ZDRSU); Ψ and 4 juveniles, Middle Don, 0 6.06.2004, Mugue ( MZH, 53040); 2 ɗ, Ψ and 8 juveniles (+5 slides of ɗ, 1 slide of Ψ), Volga delta, Damchik, 3–4 m, 18.09.2003, Väinölä ( MZH, 53005; GenBank DQ779862 , DQ779863 , DQ779864 ); 15 juveniles, same location, 19.09.2003, Audzijonyte ( MZH, 53041); 10 juveniles, same location, 0 9.2003, Daneliya, Audzijonyte ( MZH, 53042); juvenile, Volga delta, Rakushechnyi ilmen, 45°46´07´´ N, 47°33´30´´ E, st. 81, N331, 7 m, sand+shells, 0 3.06.1904, “Strazha” ( ZIN, 5696); Ψ, 45°32´30´´ N, 47°45´30´´ E, st. 83, N337, 3 m, sand, 0 3.06.1904, “Strazha” ( ZIN, 5695); ɗ and Ψ, 45°37 N, 47°40´45´´ E, st. 108, N410, 8 feet (~ 2.5 m), 18.06.1904, “Strazha” ( ZIN, 5699); 6 ɗ, 6 Ψ and juvenile, Caspian Sea, Mangyshlak, Baer ( ZIN); 46 specimens, Danube delta, Staro-Stambulskoe girlo, st. 12, 8– 10 m, 25.08.1958, Zhadin ( ZIN, 38267); 3 ɗ, Caspian Sea, Southern Coast, 1877, Baer ( ZIN, 2635); 20 juveniles, Caspian Sea, 43°20´45´´ N, 47°42´E, st.

77, N313, 19 m, dark grey mud, 30.05.1904, “Strazha” ( ZIN, 5697); 5 Ψ and 2 juveniles, Caspian Sea, 42°58´N, 47°40´E, st. 89, N355, 22 m, 0 7.06.1904, “Strazha” ( ZIN, 5698); 2 juveniles, Kaspiske Hav (Caspian Sea) ( ZMUC); juvenile (slide), G.O. Sars ( ZMO, F12167); ɗ (slide), G.O. Sars ( ZMO, F12168); ɗ (slide), G.O. Sars ( ZMO, F12169); ɗ (slide), G.O. Sars ( ZMO, F12170); ɗ (slide), G.O. Sars ( ZMO, F12171); 2 juveniles, Kaspisch. Meer (Caspian Sea) ( ZMB); ɗ, Ψ, 3 subadult Ψ and juvenile (+ 2 slides of ɗ), Donaudelta (Danube Delta), Lacul Razelm, bei Sarichiei, 44°57´N, 28°52´E, 1.5 m, 17.4o C, 516 ìS/cm, Schlamm, Dreissena , Cardium -Schalen, hohe Trübe, Bodennetz, 31.05.1997, Wittmann ( MZH, 53006; GenBank DQ779868 , DQ779869 ; DQ779861 – this sequence was mistakenly attributed to a sample from the Caspian Sea in Audzijonyte et al. 2006); 2 Ψ (+slide of Ψ), Northern Caspian Sea, Russia, 0 7.2004, Cristescu ( MZH, 53028; Gen- Bank AY529030 ).

Revised description. Body stout; body length of mature males 13–26 mm, of 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; distal margin does not cover the last thoracic segment. Sternites and last abdominal segment usually almost black in juveniles, rarely in adults. Telson longer than the last abdominal segment, tapering distally; proximal width 2.5–3.2 times distal width; length 2.1–2.5 times proximal width; cleft small, acute- or right-angled, usually with 2 (but sometimes 1–5) denticles and fine setae; lateral margins with 13–20 spine-setae.

Antennular peduncle only slightly shorter than antennal peduncle. Antennal scale less than twice the length of the antennular peduncle; distal part rather wide, distal width 0.7–0.8 of maximal width; frontal margin slightly advanced; length 2.7–3.1 times the maximal width.

Mandibular palp: 2nd segment 1.7–1.8 times longer than 3rd segment; ventral setae of the 2nd segment quite long, densely set. Maxilla II: exopod rather wide; slightly longer than wide, with long proximal and short distal setae; proximal setae protrude from the lateral sides of carapace at the pleurocervical fissures in dorsal view; second segment of endopod with 9–14 pinnate setae and one to three distal spine-setae.

Maxillipede I: merus length 1.5-1.8 times its width. Maxillipede II: ischium length 1.2–1.6 times ischium width; merus length 1.7–2.2 times merus width; merus 1.1–1.2 times as long as ischium; carpopropodus 2.0– 2.7 times as long as dactylus; dactylar dorsal setae strong, claw-like, strongly serrated; dactylar ventral setae about twice as longer as the dorsal claw-setae; terminal dactylar claw-setae strongly serrated.

Pereiopods: merus of endopod 0.7–0.8 times as long as ischium; carpopropodus with four segments. Pereiopod I: ischium length 2.5–3.2 times ischium width; merus length 2.2–2.4 times merus width; 4th segment of carpopropodus 0.6 times as long as 3rd segment; one or two paradactylar claw-setae with wide, strong denticles ( Fig. 7 e). Pereiopods II–VI: paradactylar claw-setae smooth or with fine, hardly visible serration. Pereiopod VI: ischium length 2.4–2.9 times ischium width.

Penis with large outer blade and one to three distal long setae. Endopod of uropod with a total of 6–13 spine-setae along one to two thirds of inner margin, with the proximal spine-setae arranged in two rows.

Diagnosis. Telson cleft usually with 2 denticles (rarely 1–5), and fine setae. Distal part of antennal scale rather wide, distal width 0.7–0.8 of maximum width; frontal margin slightly advanced. Exopod of maxilla II rather wide, length slightly greater than width. Pereiopod I merus length 2.2–2.4 times merus width. Paradactylar claw-setae of pereiopods II–VI smooth or with fine, hardly visible serration.

All the above listed characters differentiate P. b a k u e n s i s from P. b a e r i. P. b a k u e n s i s is also morphologically close to P. e u r y l e p i s and is distinguished from this species by narrower antennal scale which is approximately three times longer than wide, and by short distal setae of the maxilla II exopod. P. bakuensis differs from P. kessleri by long proximal and short distal setae of the maxilla II exopod, so that long proximal setae protrude from the sides of head next to pleurocervical fissures; by merus of pereiopod I 0.7–0.8 times as long as ischium; the length of 4th segment of carpopropodus, which is 0.6 of 3rd segment length; by the spine-setae of uropod endopod, set in two rows proximally.

Molecular characters. P. bakuensis is characterized by a specific mitochondrial DNA lineage typified by a CO1 gene fragment sequence (GenBank DQ779864 ), from which most conspecific specimens (N = 12; DQ779862 – DQ779869 ) differ by less than 1.2%, whereas divergence from the closest species P. baeri is> 7.2% ( Audzijonyte et al. 2006).

However, two specimens from Northern Caspian Sea, identified here as P. b a k u e n s i s (initially studied by Cristescu & Hebert (2005) and referred to as P. cf. baeri II in Audzijonyte et al. (2006)), have another distinct mtDNA lineage that is equally divergent from the rest of P. b a k u e n s i s and P. baeri (c. 7%). The molecular variation in P. b a k u e n s i s and possible presence of cryptic species thus require further study.

Distribution. Endemic of the Ponto-Caspian basin. Central and Southern Caspian coasts, Northern Caspian Sea, Volga River; the Sea of Azov, Don and Kuban rivers; Danube River (Black Sea basin) (Fig. 1).

Habitat. Upper sublittoral (0–8 m). Fresh and oligohaline waters (0–5‰, rarely up to 9‰), rivers up to over 500 km upstream. Sandy, muddy-sandy bottom (psammophilic). Together with P. ullskyi , P. intermedia , occasionally with P. baeri in the Caspian Sea.

Remarks. Sars (1895) distinguished P. bakuensis from P. baeri by the overall habitus, the shape and armature of telson, the shape of antennal scale and merus of pereiopods. The body and thoracopods of P. bakuensis are slightly stouter than those of P. baeri . Telson of P. b a k u e n s i s is less tapering and usually has two denticles in the cleft, while P. baeri always has more than two denticles. Antennal scale of P. bakuensis is usually more convex distally and concave at the outer margin. Martynov (1924) independently used the same characters to describe the Don River subspecies P. baeri bispinosa . In fact, the difference in the habitus between P. bakuensis and P. baeri in not so easy to see, and the species are hard to distinguish by stoutness alone. The shape of telson and number of denticles in the telson cleft may also mislead due to the occasional overlap. Therefore, after the inspection of large collections from the Caspian Sea, Derzhavin (1939) doubted the distinctness of P. bakuensis as a separate species and synonymized it with P. b a e r i.

The most reliable character that separates the two species is the structure of paradactylar claw-setae of pereiopods. Both species, like other species of the genus Paramysis , have strong denticles on paradactylar claw-setae of pereiopod I. Denticles are also present on paradactylar setae of other pereiopods in P. baeri , but not in P. bakuensis (neither in P. e u r y l e p i s and P. kessleri ). This might be related to different substrate utilization, although no direct observations exist so far. Additionally, the characters of telson, antennal scale, exopod of maxilla II and merus of pereiopod can be used for the identification.

Figures

FIGURE 6. Paramysis bakuensis G. O. Sars, 1895: (a, c – e) lectotype, subadult Ψ; (b) Ψ, Volga delta, head; (a) total view; (c) maxillipede I, frontal view; (d) maxillipede II, frontal view; (e) pereiopod I (setae and dactylus missing), frontal view. Scales: (a), (b) 1 mm, (c), (d), (e) 0.25 mm.

FIGURE 7. Paramysis bakuensis G. O. Sars, 1895: (a, c) lectotype, subadult Ψ; (b, d – g) Ψ, Volga delta; (a) telson (terminal spine-setae missing); (b) telson, distal part; (c) antennal scale, dorsal view; (d) exopod of maxilla II, caudal view; (e) pereiopod I, frontal view; (f) pereiopod VI, frontal view; (g) dactylus of pereiopod VI, frontal view. Scales: (a) 1 mm, (b), (c), (e), (f), (g) 0.5 mm, (d) 0.25 mm.