Babr baikali Stebbing 1899

Babr baikali (Stebbing, 1899)

(Figures 3 – 7)

Gammarus Lovenii Dybowsky, 1874: 137, Tab. XIII, Fig. 7, [non G. lovenii Bruzelius, 1859]; Pallasea baikali (partim) Stebbing, 1899: 422; Stebbing, 1906: 378; Sowinsky, 1915: 272; Pleuracanthus lovenii Garjajev, 1901: 42;

Pallasea (Pallasea) baikali Bazikalova, 1945: 144; Barnard & Barnard, 1983: 480; Pallasea kessleri var. inermis Sowinsky, 1915: 265;

P. baikali inermis Dorogostaisky, 1922: 123, Tab. 2, Fig. 4;

Pallasea (Pallasea) baikali inermis Bazikalova, 1945: 145; Barnard & Barnard, 1983: 480; P. baikali Väinölä & Kamaltynov, 1999: 951 [“ P. baikali M+N”]; P. (Pallasea) baikali baikali Takhteev, 2000: 60;

Babr baikali Kamaltynov, 2002: 756;

Babr inermis Kamaltynov, 2002: 756.

Type material. Lectotype, male, 22 mm, “Loveni”, Baikal, 1873 (ZIN 1/88436). Paralectotypes: 1 juvenile, Baikal (ZIN 1/88436); 1 male, 27.5 mm, “ Gammarus loewenii” (ZMH 21667).

Additional material examined. (The following notations are used: sites are mainly listed counterclockwise following shoreline; locality name is followed by a basin code (S=southern, C=central, N=northern main basin of Lake Baikal, see Fig. 1); station codes (st.) refer to the cruises of respective years on r/v Obruchev (91-x =1991) and r/v Titov (99-x, 00-x, 06-x and 07-x); collector acronyms are MED=Mikhail Daneliya, RMK=Ravil Kamaltynov, RV=Risto Väinölä; the numbers of specimens examined by different methods are indicated as mor: for morphology, all: for allozymes and mtD: for the mitochondrial COI gene sequence. Museum collection numbers given after the mor: specification are MZH =Zoological Museum, University of Helsinki; LIN=Limnological Institute, Irkutsk, ZIN =Zoological Institute, St. Petersburg).

Kultuk Bay (S), 51°43´N, 103°43´E, sandy beach 0.5 m, 14.09.1998, coll. RV & RMK (mor: 2 MZH 53152; all: 9; mtD: 3);

Kultuk Bay (S), 51°43´N, 103°43´E, 2−3 m sand, 14.09.1998, coll. RV (mor: 2; all: 2)

Kultuk Bay (S), 53º 43'13'' N, 103º42'54'' E (st. 07-64), 0.5–1 m sand, 14.08.2007 coll. RV & MED (mor: 77 MZH 53153; mtD: 2);

same location and date, 2–3 m, sand, stones, vegetation (mor: 19 MZH 53154);

Kultuk Bay (S), 51°43´02´´ N, 103°43´10´´ E (st. 07-62), 10 m, sand, 14.08.2007, coll. MED & RV (mor: 4 MZH 53155, 53175; mtD 1);

Cape Ulan-Koblit (unknown locality), 18 m, mud, algae, 31.07.1916, coll. Baikal Expedition (mor: 1 ZIN);

Budyskaya Guba (Olkhon Island; C), 53°07´37´´ N, 107°29´12´´ E (st. 07-14), 2–3 m, sand, 0 6.08.2007, coll. RV & MED (mor: 33 MZH 53157; mtD: 5);

Olkhon Strait, Khul Bay (C/N), 53°04´N, 106°56´E (st. 91-4), 7−15 m, Charales, 16.08.1991, coll. RMK & RV (mor: 1; all: 2; mtD: 3)

Olkhon Strait, Khul Bay (C/N), 53°04´N, 106°56´E (st. 00-14), 2−9 m, 23.09.2000, coll. RMK & RV (mor: 1; mtD: 1)

Olkhon Strait, Khul Bay (C/N), 53º03'04'' N, 106º55'56'' E (st. 07-15a), 2–3 m, sand, vegetation, 0 6.08.2007, RV & MED (mor: 32 MZH 53158; mtD: 1);

Maloe More strait, Bayan-Shungen Bay (N), 53°15´21´´ N, 107°29´30´´ E (st. 07-16a), 1–2 m, sand, 0 6.08.2007, coll. RV & MED (mor: 49 MZH 53159, 53174; mtD: 5);

Maloe More, Toubdi (N, exact locality unknown), 13.07.1897, coll. Botkin (mor: 1 LIN 854);

Boguchanski Bay (N), 55°25´21´´ N, 109°11´18´´ E (st. 06-14), 0.5–1.5 m, sand, 15.08.2006, RV & MED (mor: 9 MZH 53161; mtD: 2);

off Yarki Island (N), 55°45´N, 109°40´E (st. 91-8), 20.08.1991, coll. RMK & RV (mor: 1; all: 43; mtD: 3);

Frolikha Bay (N), 55°31´N, 109°51´E (st. 99-54), 13−30 m, 26.7.1999, coll. RV & RMK (mor: 1; mtD: 3);

Ayaya Bay (N), 55°27´22´´ N, 109°53´58´´ E (st. 06-22a), 0.5–1.5 m, sand, 15.08.2006, coll. RV & MED (mor: 16 MZH 53160; mtD: 1);

Davsha Bay (N), 54°20´N, 109°29´E (st. 07-34b), 2 m, sand, 0 9.08.2007, coll. RV & MED (mor: 36 MZH 53162, 53173; mtD: 5);

Senogda Bay (N, 55°34´N, 109°13´E), st. 633, 2 m, sand, 0 9.07.1955, coll. Bazikalova (mor: 1 LIN 868);

Irinda Bay (N), 54°50´N, 109°40´E (st. 91-10), 21.08.1991, coll. RMK & RV (mor: 1; all: 9; mtD: 3);

1 km S from mouth of Malaya Cheremshana River (N), 54°00´N, 109°24´E (st. 99-39), 25.7.1999, 15– 25 m, coll. RMK & RV (mor: 1; mtD: 1);

Chivyrkui Gulf, Zmeinaya Bay & Pesochnaya Bay (N), 53°45´N, 109°01´E (st. 00-28/29), 1m / 4m sand, 25.9.2000, coll. RV (mor: 2; mtD: 2);

Chivyrkui Gulf, Kurbulik (N), 53°42´N, 109°02´E (st. 91-11), sand, 22.08.1991, coll. RV (all: 7).

Barguzin Bay, off Cape Kholodyanka (C), 53°23´N, 108°59' E (st. 99-27), 4−7 m, sand, 23.07.1999, coll. RV & RMK (mor: 3 MZH 53156; mtD: 3);

Bezymyannaya Bay (C), 53°02´N, 108°18´E (st. 99-21), 23.7.1999, 2.5−4 m sand, coll. RMK & RV (mor: 2 MZH 53170; mtD: 3);

Talanki Bay (C, 52°42´N, 107°41´E), st. 1194, 10 m, 21.07.1957, coll. Bazikalova (mor: 1 LIN 867);

Off Selenga delta mouth (S/C), 2 m, mud, 0 8.05.1915 (mor: 12 ZIN 2/88439 " Pall. baikali inermis Sow., det. Dorogostaisky");

Off Severnoe Ustie mouth (S/C, 52°23´N, 106°33´E), 2 m, 0 8.05.1915, collector unknown (mor: 1 LIN 851 " Pallasea (Pallasea) baicali inermis, det. Dorogostaisky");

Off Posolskoe, southern edge of Selenga delta (S), 52°01´N, 106°10´E (st. 99-6), 3.5 m, sand, 21.7.1999, coll. RV & RMK (mor: 1; mtD: 1)

Type locality. Lake Baikal, Kultuk Bay (southern basin; as specified in Kamaltynov 2002).

Diagnosis. Marginal prominences of head about equal in length to marginal prominences of pereonite 1 (Fig. 4 b). Uronite 1 with dorso-lateral setae only (Fig. 4 c). Antenna 1 shorter than or equal to a half of body length (Fig. 4 a). Antenna 1 peduncle segment 1 1.1–1.2 times as long as segment 2, and segment 2 1.5 times as long as segment 3 (Fig. 4 a, 5a). Mandibular palp segment 1 without setae; segment 3 with 16 to 22 short ventral spine-setae (Fig. 5 b). Coxa 4 with straight distal margin (Fig. 4 a). Posterior margin of pereopod 6 basis slightly concave (Fig. 6 c). Uropod 3 shorter than urosome (Fig. 4 a), rather wide. Uropod 3 exopod 1.3–1.5 times as long as endopod (difference in the length especially strong in younger specimens) (Fig. 7 a).

Color white, greenish-white or yellowish-white; spots varying in color from slight greenish-brown, yellowish or reddish to dark red or black, varying with the size of animal and substrate (environment). Pereonites 1−5 all with narrow dorso-lateral spots (Fig. 3 a, b).

Body length of mature individuals 21–33 mm.

Description of lectotype. Fitting the generic and specific diagnoses above, with following specifications: Marginal prominences of head conical, sharp. Uronite 2 with two dorso-lateral spine-setae. Uronite 3 with three dorso-lateral spine-setae. Antenna 1 length 0.43 of body length. Antenna 1 about 1.5 times as long as antenna 2. Flagellum with 26 subsegments. Length of antenna 2 peduncle segment 4 equal to segment 5 length. Mandibular palp segment 3 with 16 short ventral spine-setae. Uropod 3 exopod 1.3 times as long as endopod.

DNA. Mitochondrial DNA typified by the sequence of a fragment of the COI deposited in GenBank with accession no GQ919203 (from a specimen from Kultuk Bay, MZH 53175), from which conspecific specimens differ at less than 10 % of nucleotide sites, whereas any heterospecific sequences studied differed at more than 15 %. The variability within B. baikali comprises four main lineages, with typical geographical distributions: southern, eastern, western (around Olkhon Island), and northern (represented by GenBank sequences GQ919203 - GQ919206). (Figs 1 a and 2).

Allozymes. Distinguished from B. nigromaculatus by having electrophoretically faster allozymes of the enzymes ENO, MDH-1 and PGD, and electrophoretically slower ones of the enzymes AAT-2, AP, ARK, IDH- 1, IDH-2, MDH-2 and PGM (Table 1).

Distribution and habitat. Throughout the coasts of Baikal (Fig. 1 a), on shallow-water sandy bottoms. Depth 0.5–30 m, more often less than 10 m.