Five subspecies of the Dorogostaiskia parasitica complex (Dybowsky) (Crustacea: Amphipoda: Acanthogammaridae), epibionts of sponges in Lake Baikal

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1 Online resource 1 Extended version of the Taxonomy section in the main paper: Mikhail E. Daneliya & Risto Väinölä Finnish Museum of Natural History, P. O. Box 17, FI-00014, University of Helsinki, Finland Correspondence: mikhail.daneliya@helsinki.fi Five subspecies of the Dorogostaiskia parasitica complex (Dybowsky) (Crustacea: Amphipoda: Acanthogammaridae), epibionts of sponges in Lake Baikal Taxonomy Family Acanthogammaridae Garjajeff, 1901 Subfamily Acanthogammarinae Garjajeff, 1901 Genus Dorogostaiskia Kamaltynov, 2002 Acanthogammarus Stebbing, 1899: 430, in part; 1906: 508, in part; Sowinsky, 1915: 301, in part Polyacanthus Garjajeff, 1901: 16, in part, nomen preoccupatum Spinacanthus Dorogostaisky, 1930: 56, in part, nomen preoccupatum; Bazikalova, 1945: 121, in part; Bousfield, 1977: 292; Barnard & Barnard, 1983: 517, in part; Kamaltynov, 1992: 28; 1999: 935 Brandtia (Spinacanthus) Bazikalova, 1948: 24, in part Dorogostaiskia Kamaltynov, 2001: 622 Composition Dorogostaiskia parasitica (Dybowsky, 1874), with five subspecies Dorogostaiskia insularis (Dorogostaisky, 1930) Dorogostaiskia birsteini (Bazikalova, 1948) Type species Gammarus parasiticus Dybowsky, 1874 Remarks There has been some confusion about the type species of the genus Dorogostaiskia. Bazikalova (1945) indicated Spinacanthus parasiticus, Takhteev (2000) Gammarus parasiticus, Barnard & Barnard (1983) either G. parasiticus (p. 365) or Spinacanthus insularis (p. 517), and Kamaltynov (2001) S. insularis as the type. The genus itself was initially described as Spinacanthus Dorogostaisky, Kamaltynov (1999) noted that Spinacanthus was a junior homonym of Spinacanthus Agassiz, 1835 (Osteichthyes), and proposed Dorogostaiskia as a new replacement name (Kamaltynov, 2001). Such a replacement taxon will retain the type species of the initial one (the Code: 67.8; ICZN, 1999). The initial description of Spinacanthus by Dorogostaisky (1930) did not directly indicate a type species. Bazikalova (1945) 1

2 fixed S. parasitica (initially described as Gammarus parasiticus Dybowsky, 1874) as the type of the genus, and Takhteev (2000) followed this. The alternative argument underlying Barnard & Barnard s (1983) and Kamaltynov s (1992, 2001) treatments seems to stem from an interpretation of Dorogostaisky s (1930) initial description of Spinacanthus, which then included four species-group taxa: S. parasiticus (Dybowsky, 1874) (=D. parasitica), S. armatus (Dybowsky, 1874) (=Dedyuola armata), S. armatus ongureni (Garjajeff, 1901) (=Dedyuola ongureni), and S. insularis Dorogostaisky, 1930 (=Dorogostaiskia insularis). The last one was introduced as a new species with the expression Spinacanthus insularis n. gen. n. sp., which could be (mis)interpreted as fixing S. insularis as the type species. However, as noted by Takhteev (2000), Article of the code states that such an expression will fix the type of the genus only if at least two new nominal species are simultaneously described, not one as in this case. Bazikalova s (1945) fixation of S. parasiticus (junior synonym of G. parasiticus) as the type, in turn, was correct and remains valid, as the first subsequent designation after the original description of the genus (Article 69.1 of the Code). S. parasiticus was originally included into the nominal genus and therefore eligible for type fixation (Code: 12), and Gammarus parasiticus Dybowsky, 1874, is to be treated as the type species of Dorogostaiskia. Dorogostaiskia parasitica (Dybowsky, 1874) sensu lato Diagnosis Length of mature specimens 6-12 mm. Spine-setae of the head on low tubercles. All keels of pereonites with spine-setae. Lobes of telson with no spine-setae (setae only). Segment 1 of antenna 1 peduncle with 8-12 spine-setae; segment 2 is times as long as segment 1. Rami of uropod 3 with no spine-setae (setae only). Comparison The adult specimens of D. parasitica sensu lato are smaller in size (body length 6-12 mm) than of D. insularis (Dorogostaisky, 1930), which are mm, and about as long as in D. birsteini (Bazikalova, 1948), which is still known only from a holotype female. From D. insularis the species differs also by the absence of high tubercles (only low ones) at the base of head dorsal spine-setae, absence of spine-setae on telson lobes and uropods 3, but more spine-setae of segment 1 of antenna 1 peduncle (only 3 in D. insularis) and shorter segment 2 of antenna 1 peduncle (1.5 times as long as segment 1 in D. insularis). From D. birsteini it differs by the presence of spine-setae on all dorsal keels (absent on pereonites in D. birsteini) and on antenna 1 (only setae in D. birsteini). From the species of the closely related genus Brandtia Bate, 1862, D. parasitica is distinguished by long antenna 1, which is about three times as long as antenna 2 (shorter than antenna 2 in Brandtia ssp.), presence of transverse prominences on pereopod 5-7 basis, long pleopods (rather short in Brandtia ssp.) and other characters. Molecular diagnosis and variation Dorogostaiskia parasitica sensu lato is characterized by a distinct mitochondrial DNA lineage (clade), whose individual haplotypes differ from any other studied taxa by > 15 % observed distance in the barcode COI gene segment (from D. insularis by %, Fig. 2). The D. parasitica lineage is typified by COI gene sequence from the type locality (GenBank KF586540, voucher A496), from which conspecific haplotypes differ by up to 11 %. In the 28S rrna gene segment studied, the D. parasitica sequence (GenBank KF586548) differs by 0.31 % from D. insularis (GenBank KF586549), while no variation was observed within the species. 2

3 Distribution Dorogostaiskia parasitica sensu lato is endemic to Lake Baikal, and is found along coasts of the whole lake except from the northern part of the North Basin north of Cape Zavorotnyi (54 18 N) on the west coast and north of the Svyatoi Nos Peninsula on the east coast (53 50 N), and from the shallows in front of the Selenga River delta which lacks sponge habitat (Bazikalova, 1945) (Fig. 1). Habitat Almost exclusively found as an epibiont on Baikalian lubomirskiid sponges, often in large numbers (Kamaltynov et al., 1993). In a number of cases was also collected from drowned wood or by dredging over the bottom (Kamaltynov, 2001; this study). Depth m, occasionally down to 200 m (Bazikalova, 1945; Kamaltynov et al., 1993; Kamaltynov, 2001; this study). During autumn partly migrates to deeper water (Kamaltynov et al., 1993). Remarks. Dybowsky (1874) noted body color variation within D. parasitica, but his observations seem to have been based on the nominotypical subspecies only. Indeed, the intensity of color may vary depending on substrate. Garjajeff (1901) also mentioned about coloration differences between northern and southern forms, but did not explicitly describe the difference. In this study, color forms strictly corresponding to geographical subspecies were found (see details in appropriate subspecific sections). Dorogostaiskia parasitica parasitica (Dybowsky, 1874) Figs 3A, 4-7, 8A, J Gammarus parasiticus Dybowsky, 1874: 147, table III fig. 3 Acanthogammarus parasiticus: Stebbing, 1899: 429, in part; 1906: 511, in part; Sowinsky, 1915: 323, in part; Dorogostaisky, 1922: 148, in part Polyacanthus parasiticus: Garjajeff, 1901: 31, in part Spinacanthus parasiticus: Dorogostaisky, 1930: 56, in part; Bazikalova, 1945: 122, table XLIX fig. 8, in part; Andres & Lott, 1977: 59; Barnard, Barnard, 1983: 517, fig. 35D, in part; Yampolsky et al., 1994: 317, in part Brandtia (Spinacanthus) parasitica: Bazikalova, 1948: 24, in part Dorogostaiskia parasitica. Kamaltynov, 2001: 623, in part Lectotype Female, 8 mm, partly dissected, appendages from one side of the body mounted on slide, the rest of the body left in alcohol, Baikal, Dybowsky (ZIN, 7144). Selected here from a specimen originally marked as typ descr and later considered a syntype (Andres & Lott, 1977; Kamaltynov, 2001). Paralectotypes Female, 8.5 mm, Baikal, Dybowsky (ZIN, 1/88488; previously in the same tube with the lectotype designated above); 2 males and 2 females (1 initially without part of abdomen), mm, Baikalsee, Dr. Dybowsky, , bought by I.D.E. Schmeltz (ZMH, 21646); designated here from former syntypes (Andres & Lott, 1977; Kamaltynov, 2001). Another 9 specimens labeled as Baikalsee, Dybowsky and registered in the museum catalogue as Gammarus parasiticus, were found in ZMB (3790/3798). Dybowsky (1874) provided measurements of only 4 specimens, but no mention of the total number of specimens studied and their type status. These specimens are provisionally considered as syntypes and hence here as paralectotypes. Type locality Lake Baikal, Southern Basin: Kultuk Bay (as designated by Kamaltynov, 2001); approximate coordinates N E [KUL in Fig. 1]. 3

4 Fig. 3 Dorogostaiskia parasitica (Dybowsky, 1874) sensu lato, color images of habitus of different subspecies, from type localities: (A) D. p. parasitica, Kultuk Bay; (B) D. p. kamaltynovi subsp. nov., Olkhon Strait; (C) D. p. hanajevi subsp. nov., Off Kocherikova River mouth; (D) D. p. ushkaniensis subsp. nov., Malyi Ushkani Island; E) D. p. stenocephala subsp. nov., Barguzin Bay Other material examined [BOY] Boyarskoe (S) (51 50 N E), st. 611/1, cl. 297/1, , coll. Baikalian Expedition of USSR AS (BEU): 1 specimen (ZIN 5/88492). [VYD] Vydrino (S) (51 28 N E), 10 m, encrusting sponge, , r/v Titov, st , dive, coll. Khanaev, Väinölä, Daneliya: 5 specimens (MZH ); 25, partly destroyed by DNA extraction (further referred to as PD) (MZH ; COI: 21; 28S: 2). [MUR] Murino Bank (S), start: N E, stop: N E, m, 5-10 cm stones encrusted by sponge, , r/v Titov, st , dredge, coll. Khanaev, Daneliya, Väinölä: 6 (MZH ). 4

5 [MUR] W of Murino (S), N E, m, encrusting sponge, , r/v Titov, st , dive, coll. Khanaev, Väinölä, Daneliya: 34 (MZH ); 30, PD (MZH ; COI: 28). [KUL] E of Kultuk (S), N E, 6-30 m, , r/v Titov, st. 7-63, dive, coll. Khanaev, Daneliya, Väinölä: 1, appendages dissected (MZH 97031); >100 specimens (MZH 97030); 1, dried and pinned (MZH ); 5 specimens, PD (MZH ; COI: 5; 28S: 1). [MAR] Cape Maritui (S) (51 47 N E), , r/v Titov, st , dive, coll. Khanaev, Daneliya, Väinölä: 45 (MZH ); 5, PD (MZH ; COI: 2). [MAR] Maritui (S) (51 47 N E), 19(16) : 9 (ZIN 3/88490). [POL] Polovinka (S), N E, 2-7 m, stones, , r/v Titov, st , dive, coll. Khanaev, Daneliya, Väinölä: 31 (MZH ). [LIS] Listvennichnyi Bay (S), Baranchiki (51 51 N E), 12 m, sponge, , dive, coll. Khanaev: 5, PD (MZH ; COI: 5); 73 (MZH ). [LIS] Listvennichnyi Bay (S), W of Listvyanka (51 51 N E), m, sponge, , dive, coll. Khanaev: >100 (MZH ). [LIS] Listvennichnyi Bay (S), entrance to Angara reservoir (51 52 N E), 24 m, drowned wood, , dive, coll. Khanaev: 70 (MZH ); 5, PD (MZH ; COI: 4). [LIS] Listvenichnoe (S), on sponge, m, , coll. Dorogostaisky: 14 (ZIN 7148). [LIS] Listvenichnoe (S), in front of harbor (51 51 N E), st. 41, 18 m, stones, sponge, : many (ZIN 4/88491). [BOK] Bolshie Koty (S), N E, 2005, coll. J. Smith: 75, PD (MZH ; COI: 6). [BOK] Between Bolshie Koty and Sennaya Bay (S), dr. 16, 12 fathoms, stones, 18(24) , coll. B. Sukachev: 24 (2 tubes) (ZIN 7142). [GOL] Goloustnoe (S) (52 02 N E), N28, 1898, coll. B. Sukachev: 2 (ZIN 7143). [GOL] Goloustnoe (S) (52 02 N E), st. 1054/1, cl. 389/1, , coll. BEU: 8 (ZIN 6/88493). [PES] Peshchanaya Bay (S), Cape Bolshaya Kolokolnya, ' N ' E, 6-9 m, encrusting sponge and wood, , r/v Vereshchagin, st , dive, coll. Khanaev, Väinölä, Daneliya: 23 (MZH ); 5, PD (MZH ; COI: 4). [PES] Peshchanaya Bay (S) (51 15' N ' E), 45 m, , coll. BEU: 3 (ZIN 7/88494); same locality, sand, , coll. BEU: 2 (ZMB 20461). [BUG] Buguldeika (C), N E, m, sponge, , r/v Titov, st. 07-9, dive, coll. Khanaev, Daneliya, Väinölä: >100 (MZH ); 5, PD (MZH ; COI: 4; 28S: 1). [KRE] Cape Krestovskii (C) (51 59 N E), 23 m, sponge, , st , coll. Kamaltynov, Väinölä: 2 (MZH ; COI: 1). 5

6 [OL5] Olkhon Gate (C), N E, , coll. J. Smith: 17, PD (MZH ; COI: 3; 28S: 1). [UKH] Olkhon Island, Cape Ukhan (C), N E, m, sponge 2 m high, rocky, pebbles, , r/v Titov, st , dive, coll. Khanaev, Daneliya, Väinölä: 31 (MZH ); 5, PD (MZH ; COI: 5). [BUD] Olkhon Island, Budyskaya Bay (C), N E, m, sponge, , r/v Titov, st , dive, coll. Khanaev, Väinölä, Daneliya: >100 (MZH ); 44 (MZH ; COI: 44; 28S: 1). Baikal, on sponge: 49 (ZIN 7145). Irkutskaya Guberniya, Putsillo, coll. Dybowsky: 5 (ZIN 2/88489). Diagnosis Head times as high as long. Dorsal keels of pereonites and pleonites triangular in lateral view. Antenna 1 slightly shorter or as long as body (0.8-1 times as long). Accessory flagellum 3-segmented; segment 2 as long as segment 1, segment 3 rudimentary. Coxal plates 1-3 with straight distal margin, usually without or rarely 1 lateral spine-seta. Distal margin of coxal plate 4 slightly concave. Dactylus of pereopods 3 and 4 is times as long as propodus. Posterior distolateral prominence of pereopod 5 basis about as long as or slightly shorter than ischium. Carpus of pereopods 5-6 is 2.0 times as long as wide and pereopod 7 is times as long as wide. Propodus of pereopods 5-7 is 5-6 times as long as wide. Color: body greenish with brown to red spots; eyes brown or dark-brown; pereonites and pleonites with lateral light blue or white spots; two golden spots in front of each dorsal keel; dorsal keels dark-brown; marginal keels red; segments of appendages with alternate red- or brown-greenish bands. Body length 6-11 mm. Comparison Morphological differences to individual sister taxa are delineated under each of the other subspecies sections, and summarised in Table 1. Live specimens of Dorogostaiskia parasitica parasitica are also readily distinguished from all other subspecies by characteristic paired golden spots between darkbrown dorsal keels. Molecular diagnosis D. p. parasitica is characterized by a distinct mitochondrial DNA lineage (Fig. 2), which is typified by the COI barcode sequence deposited as GenBank accession KF (from type locality). This lineage differs from other subspecies in 5-11 % of nucleotide sites, whereas observed intra-subspecies differences were < 5 %. Description of lectotype Body wide, about 3 times as long as wide. Head 1.5 times as high as long, with 2 postrostral, 4 dorsal, 1 lateral on each side and 4 marginal spine-setae on low tubercles, slightly bent backwards. Rostrum wide, short, angular. Interantennal blade with smooth lower and upper angles; lower margin parallel to dorsal side of head. Eyes convex, oval 1.4 times as long as wide and 0.4 times as wide as head length. Pereo- and pleonites with high, flat, but not sharp, triangular dorsal keels, slightly directed backwards. Each keel with 3 pairs of spine-setae. Dorsal keel of pereonite 1 and pleonites with a pair of basal anterior spine-setae. Pereonites with high, flat marginal keels, bearing 1 line of 3-5 spinesetae and 1 basal posterior spine-seta. Pleonites with 1 posterolateral and 1-2 marginal spine-setae. Marginal spine-setae of pleonites 1 and 2 on low prominences. Epimera distally rounded, with rare setae. Epimeron 1 shorter than epimera 2 and 3. Epimera 1 and 2 with transverse rib. Uronites 6

7 smooth, with rare setae. Telson about as long as uronite 3, bilobate; each lobe with 1 dorsomedial and 2 long apical setae. Fig. 4 Dorogostaiskia parasitica parasitica (Dybowsky, 1874), A, B, lectotype (ZIN 7144), C, Kultuk Bay (MZH ): (A) lateral view (thoracic appendages not shown); (B) dorsal view (antennae and distal part of abdomen not shown); (C) entire anterolateral view. Scales, 1 mm 7

8 Antenna 1. Peduncular segment 1 is 1.1 times as long as segment 2, with proximal anterolateral tubercle, bearing setae, 10 anterior irregularly set spine-setae, slightly bent backwards, and 2 posterior distomedial spine-setae, directed forward. Peduncular segment 2 as long as segment 3, with 4 groups of setae; segment 3 with 5 groups of setae. Accessory flagellum 3-segmented; segment 2 as long as segment 1, segment 3 rudimentary. Antenna 2 with long setae, up to 3 times as long as width of segments; antennal conus about as long as peduncular segment 3; peduncular segment 4 is 1.2 times as long as segment 5, with 5 anteromedial and 3 posterolateral bunches of setae; segment 5 with 4 medial and 3 posterolateral bunches of setae. Flagellum 7-segmented; flagellar segments with multiple distal dorsal, ventral and medial setae. Labrum distally with two fields of fine short setae, directed medially. Mandible. Incisors with 5 cusps. Left lacinia mobilis with 4 cusps. Inner margin with a row of 6 spine-setae and plumose setae between them. Molar with long plumose gnathobasic seta. Palp segment 2 is 1.1 times as long as segment 3, with gap between posterior setae. Palp segment 3 is 2.9 times as long as wide, with 3 medial and 3 lateral bunches of setae, 18 palmar and 5 apical setae. Labium bilobate; lobes with distolateral, distomedial and medial fields of fine setae, directed medially. Maxilla 1. Inner plate with 12 plumose setae. Outer plate with strong claw-setae with bearing distal denticles; medial marginal claw-seta with thin denticles, other with strong. Left palp segment 2 with stout setae and 1 outer thin seta. Right palp segment 2 with 3 short triangular spine-setae, 1 outer stout seta and 1 thin seta. Maxilla 2. Outer and inner plates with multiple setae. Maxillipede. Coxa with proximal posterior bunch of 5 setae, 2 distal posterior and 3 lateral setae. Basis with lateral seta and distal posterior bunch of setae. Basis endite reaches distal margin of merus, with distal plumose setae and 3-4 tooth-like spine-setae. Ischium with posterior distal bunch of setae. Ischium endite oval, large, about as long as and wider than carpus. Ischium endite with short outer setae, long medial setae, 6 tooth-like medial spine-setae, distally transferring into thinner and longer spine-setae and eventually plumose setae. Merus with distal medial bunch of setae. Carpus 1.2 times as long as propodus, with dense posteromedial setae. Propodus with 3 medial bunches of setae, part of which plumose, central anterolateral seta and distal anterolateral bunch of setae. Dactylus 0.9 times as long as propodus and 3.5 times as long as wide, with distal setae. Dactylar unguis thin, 0.6 times as long as dactylus. Coxal plates 1-4 with rounded distal anterior angle covered by rare setae. Coxae 5-7 with anterior lobe. Coxal plates 1-3 with straight distal margin and without lateral spine-setae. Coxal plate 4 with slightly concave distal margin, 1 anterolateral and 3 posterolateral spine-setae. Gnathopods subequal in size. Gnathopod 1. Basis anterior margin with short setae and proximal long setae; posterior margin with many long setae. Ischium with bunch of setae. Merus with 2 posterior bunches and 1 distal medial bunch of setae. Carpus with 2 anterior bunches of setae, 2 posteromedial and 3 posterolateral bunches of setae. Propodus almond-shaped, with 4 anteromedial, 5 posteromedial and 4 posterolateral bunches of setae and spine-setae. Palmar margin convex, with short setae. Dactylus with anterior seta. Gnathopod 2. Basis with long posterior and proximal anterior setae, and short distal anterior setae. Ischium and merus with 2 posterior bunches. Carpus with distal anterior bunch, distomedial bunch and 4 posterior bunches of setae. Propodus slightly wider distally than proximally, with 4 anteromedial, 3 posteromedial and 4 posterior bunches of setae. Palmar angle with 3 spine setae. Palmar margin convex with short setae. Dactylus with anterior seta. Pereopods strong. Ischium with 1-2 anterior bunches of setae. Merus and carpus distally wider than proximally, lobed. Propodus cylindrical, with distal anterior paradactylar pair of spine-setae. Dactylus with 2 distal anterior and 1 proximal posterior setae. Dactylar unguis strong, about as long as dactylus. Pereopods 3 and 4 subequal, shorter than pereopods 5-7. Merus with distal posterior bunch of spineseta and setae. Carpus rather short, about half of merus and propodus. Dactylus times as long as propodus. Pereopod 3. Merus 1.8 times as long as carpus, with 3 anterior and 1 posterior bunches of setae. Carpus with distal posterior bunch of setae. Propodus 2.0 times as long carpus, with 2 8

9 anterior and 2-3 posterior bunches of setae. Pereopod 4. Merus 1.6 times as long as carpus, with 3 anterior and 2 posterior bunches of setae. Carpus with distal anterior and distal posterior bunch of setae. Propodus 2.2 times as long as carpus, with 2 anterior and 2 posterior bunches of setae. Pereopods 5-7. Pereopod 5 about as long as pereopod 6 and longer than pereopod 7. Basis times as long as merus; anterior margin with proximal bunch of long setae, median short setae and distal bunch of short setae; posterior surface with lengthwise depression and distolateral prominence with spine-setae. Posterior distolateral prominence of pereopod 5 basis longer than prominence of pereopod 6 basis; and prominence of pereopod 6 longer than of pereopod 7. Posterior margin of basis proximally also with triangular lobe, particularly distinct in pereopods 7. Merus with 2 proximal anterior bunches of setae; posterior margin with 2 bunches of 1-3 spine-setae and setae. Posterior margin of carpus with 2-3 bunches of 1-3 spine-setae and setae. Carpus times as long as merus. Propodus times as long as merus and times as long as wide. Posterior margin of propodus with 4 bunches of setae. Dactylus times as long as propodus. Pereopod 5. Basis posterior distolateral prominence shorter than ischium; posteromedial margin and prominence with 3 spine-setae. Carpus 2 times as long as wide. Propodus anterior margin with 2 bunches of setae; distal subterminal bunch also with spine-seta. Pereopod 6. Basis posterior distolateral prominence significantly longer than prominence of pereopod 7, with 2-3 spine-setae; posterolateral margin with 1 spine-seta; posteromedial margin with 2 spine-setae and short setae. Carpus 2 times as long as wide. Propodus with predistal anterior bunch of spine-seta and setae. Pereopod 7. Basis posterior distolateral prominence with 1 spine-seta; posteromedial margin with 1 distal spine-seta and short setae. Carpus 1.7 times as long as wide. Propodus anterior margin with distal subterminal bunch of 2 spine-setae and setae. Pleopods quite long, about as long as pleon; rami segmented. Uropods 1 and 2: peduncle times as long as inner ramus; inner ramus 1.3 times as long as outer ramus; rami with medial setae and 5 terminal spine-setae; middle terminal spine-seta longer than lateral terminal. Uropod 1 about as long as uropod 3. Peduncle with medial setae, distal dorsomedial spine-seta and 5-6 dorsolateral spine-setae, the last of them twice as long as previous. Uropod 2 extends beyond peduncle of uropod 1. Peduncle with medial setae and 2 dorsolateral spine-setae. Uropod 3. Peduncle short, only half as long as rami, with distal dorsolateral spine-seta and dorsomedial setae. Outer ramus 1.1 times as long as inner ramus, with rudimentary segment 2. Setae about as long as rami. Outer ramus with simple lateral and plumose medial setae in distal part. Inner ramus with plumose setae around margins; lateral setae only in distal part. Variation (non-diagnostic characters) Body length mm (up to 11 mm in non-type material). Eye times as long as wide. Antenna 1 is times as long as antenna 2. Peduncular segment 1 of antenna 1 is times as long as segment 2. Flagellum of antenna 1 is segmented. Flagellum of antenna 2 is 7-9- segmented. Mandubular palp segment 3 is times as long as wide, with 2-4 medial and 2-3 lateral bunches of setae and palmar setae. Distribution The nominotypical subspecies D. p. parasitica is distributed in the Southern basin and west coast of the Central basin of Lake Baikal, including the SW coast of the Olkhon Island (Fig. 1a, b). In the Olkhon Gates Strait it is substituted by D. p. kamaltynovi subsp. nov. Remarks Since Dybowsky s (1874) sampling was obviously restricted to Southern Baikal, where only the nominate subspecies had been encountered, the original morphological description can be narrowly attributed to D. p. parasitica. It was not originally noticed (Dybowsky, 1874) that the accessory flagellum has a third rudimentary segment. Bazikalova (1945) might have studied the material from 9

10 other parts of the lake, particularly because she mentioned that the species is distributed throughout the entire Baikal except for Selenga delta area, despite the existing museum collections contain the samples from Southern Baikal only. She mentioned spine-setae on segment 2 of antenna 1, which in fact are absent in this and all the other subspecies. She also stated the conus of antenna 2 to be shorter than peduncular segment 3, while they in fact are equally long; segments 4 and 5 of antenna 2 to be equal in size, while segment 5 in fact is slightly shorter; propodites of pereopods lacking spine-setae, while in fact subterminal and terminal anterior spine-setae are present in all the subspecies. Bazikalova referred to coxal plates as epimeral plates. A detailed electron microscopy study of the mandible was made by Mekhanikova (2010), presumably on D. p. parasitica, though the exact sampling locality was not mentioned. Dorogostaiskia parasitica kamaltynovi Daneliya & Väinölä, subsp. nov. Figs. 3B, 8B, G, N, 9D Polyacanthus parasiticus: Garjajeff, 1901: 31, in part; table I Spinacanthus parasiticus: Yampolsky et al., 1994: , in part (sample 9) Holotype Female, 8 mm, partly dissected, appendages mounted on slide: Baikal, Olkhon Gates Strait (N/C basin), Khul Bay [KHU], N E, 12 m, on sponge, , r/v Titov, st , dive, coll. Khanaev, Daneliya, Väinölä (MZH 53189; slide ). Paratypes [KHU] From the same sample as the holotype: 94 specimens (MZH 53190); 3 males, 4 females, mm, 2 juveniles, mm (ZIN 1/88505); 7, PD (MZH 53191; COI: 6); [BUN] Baikal, Maloe More (N basin), Cape Budun, N E, 7-9 m, sponge, , r/v Titov, st b, dive, coll. Khanaev, Daneliya, Väinölä: 17 males, 50 females, mm (MZH 53199); 11, PD (MZH 53200; COI: 11; 28S: 2); 1 female (dried and pinned), 8 mm (MZH 97001); [OL2] Baikal, Olkhon Strait (N/C basin), Zagli Bay N E, m, , r/v "Vereshchagin", st , dive, coll. Grachev, Daneliya, Väinölä: 85 specimens, mm (MZH 97002); 5, PD (MZH ; COI: 5; 28S: 1); [OL4] Baikal, Olkhon Strait (N/C), Kurkut Bay, N E, m, sponge, , r/v Vereshchagin, st , dive, coll. Zagibalova, Daneliya, Väinölä: 3 females, 8.5 mm (1 with embryos and 1 with hatchlings), 8.5 mm, 1 juveline, 5.5 mm (MZH 97003); 5, PD (MZH 97004; COI: 5); [OL1] Baikal, Olkhon Strait (N/C), Cape Umysh-Tome, N E, 18.3 m, sponge, , r/v "Vereshchagin", st , dive, coll. Zagibalova, Daneliya, Väinölä: female, 7 mm, 5 juveniles, mm (MZH 97005); 5, PD, same label as for previous (MZH 97006; COI: 5; 28S: 1); [ARA] Baikal, Maloe More (N), Cape Aral, N E, m, dredging, fine and coarse sand, algae, , r/v Titov, st , dredge, coll. Daneliya, Väinölä: 8 males, 7 females (MZH 97008); 5, PD (MZH 97009; COI: 4); 10

11 Fig. 5 Dorogostaiskia parasitica parasitica (Dybowsky, 1874), lectotype: (A) antenna 1, lateral view; (B) accessory flagellum, lateral view; (C) antenna 2, medial view; (D) labrum; (E) labium; (F) left mandible; (G) right maxilla 1; (H) left maxilla 1; (I) maxilla 2; (J) maxilliped, posterior view. Scales: A, C, J, 1 mm, B, 0.25 mm, D-I, 0.5 mm 11

12 Fig. 6 Dorogostaiskia parasitica parasitica (Dybowsky, 1874), lectotype: (A) gnathopod 1, medial view (proximal part not shown); (B) gnathopod 2, lateral view; (C) pereopod 3, lateral view; (D) pereopod 4, lateral view; (E) pleopod 1, posterolateral view; (F) pleopod 2, posterolateral view; (G) pleopod 3, posterior view. Scales: A, B, 1 mm, C-G, 0.5 mm 12

13 Fig. 7 Dorogostaiskia parasitica parasitica (Dybowsky, 1874), lectotype: (A) pereopod 5, lateral view; (B) pereopod 6, lateral view; (C) pereopod 7, lateral view; (D) telson, dorsal view. Scales: A-C, 1 mm, D, 0.5 mm [ZAM] Baikal, Maloe More (N), Cape Zama, N E, 11 m, sponge, , r/v "Vereshchagin", st , dive, coll. Zagibalova, Daneliya, Väinölä: 30 males, 41 females, mm (MZH 97010); 10, PD (MZH 97011; COI: 5; 28S: 1). Etymology Named for our senior colleague Dr. Ravil M. Kamaltynov (Limnological Institute, Irkutsk), who introduced us to Lake Baikal amphipods, and who first noticed the distinction of this Olkhon Strait / Maloe More form of D. parasitica as a potentially new taxon. 13

14 Diagnosis Head times as high as long, with 4 dorsal spine-setae. Dorsal keels of pereonites and pleonites distally rounded or subrectangular in lateral view. Antenna 1 slightly shorter than body: times as long as body. Acessory flagellum 2-3-segmented, terminal segment rudimentary. Distal margin of coxal plates 1-3 convex; lateral surface without or with 1-2 spine-setae. Distal margin of coxal plate 4 straight. Dactylus of pereopods 3 and 4 is 0.5 times as long as propodus. Posterior distolateral prominence of pereopod 5 basis shorter than or as long as ischium. Pereopods 5-7, carpus times as long as wide and 0.8 times as long as merus. Propodus of pereopods 5 and 6 is 4 times as long as wide; propodus of pereopod 7 is 3.5 times as long as wide. Color: body greenish with darkbrown to red spots; eyes brown; pereonites and pleonites with lateral light blue or white spots; dorsal and marginal keels dark-brown; segments of appendages with alternate brown and greenish bands. Body length mm. Comparison Differs from all other subspecies by shorter and stronger pereopods, particularly carpus and propodus of pereopods 5-7. From the parapatric D. p. parasitica also differs by rounded or subrectangular dorsal keels (triangular in D. p. parasitica), convex distal margins of coxal plates 1-3 (straight in D. p. parasitica) and straight distal margin of coxal plate 4 (slightly concave in D. p. parasitica), and in coloration by the absence of dorsal golden spots. See the differences from other subspecies in appropriate sections and in Table 1. Molecular diagnosis Characterized by a distinct mitochondrial DNA lineage, typified by the COI barcode sequence deposited in GenBank as accession KF (from a paratype MZH 53191, voucher A82, type locality). The lineage differs from other subspecies at 9-10 % of COI gene nucleotide sites; whereas observed intra-subspecies differences were < 3 %. Description of holotype Body wide, about 3 times as long as wide. Head about 1.5 times as high as long. Head with 2 postrostral, 4 dorsal, 1 lateral and 5-6 marginal spine-setae on low tubercles. Rostrum wide, short, angular. Interantennal blade with smooth lower and upper angles; lower margin parallel to dorsal side of head. Eyes convex, oval, 1.6 times as long as wide and 0.4 times as wide as head length. Pereonites and pleonites with high, flat, but not sharp, rounded dorsal keels, slightly directed backwards. Each keel with 3 pairs of spine-setae. Dorsal keel of pereonite 1 and pleonites 2 and 3 with a pair of basal anterior spine-setae. Pereonites also with high, flat, rounded marginal keels with 1 line of up to 8 spine-setae. Pleonites with 1-2 posterolateral spine-setae. Pleonite 1 with 2 marginal spine-setae on slight prominence. Pleonite 2 with marginal spine-seta. Uronites 2 and 3 with lateral spine-seta. Epimera distally rounded, with rare setae. Epimeron 1 shorter than epimeron 2 and 3. Epimeron 1 and 2 with transverse rib. Telson as long as uronite 1, bilobate; each lobe with 1 dorsomedial seta and 2-3 distal setae. Antenna 1 is 0.9 times as long as body and 2.3 times as long as antenna 2, with setae about twice as long as width of segments. Peduncular segment 1 is 1.3 times as long as segment 2, with proximal anterolateral tubercle, anterior irregularly set spine-setae and 2 posterior distomedial spinesetae. Peduncular segment 2 about as long as segment 3, with 4 posteromedial and posterolateral bunches of setae. Peduncular segment 3 with 4 groups of setae. Acessory flagellum 2-segmented; distal segment rudimentary. Flagellum 20-segmanted; proximal segments with bunches of long setae; distal segments with short setae. Antenna 2 with long setae, up to 3 times as long as width of segments. Conus about as long as peduncular segment 3. Peduncular segment 4 is 1.1 times as long as segment 5; segments 4 with 3 anteromedial and 3 posterolateral bunches of setae. Segment 5 with 3 14

15 medial and 3 posterolateral bunches of setae. Flagellum 8-segmented. Flagellar segments with multiple distal dorsal, ventral and medial setae. Mandible. Incisors with 5 cusps. Right lacinia mobilis bifurcate; lower spine distally flattened, with 6 terminal denticles. Left lacinia mobilis with 4 cusps. Inner margin with row of 6 finely serrated spinesetae and plumose setae between them. Palp segment 2 as long as 3, with 16 posterior setae. Segment 3 with 3 medial and 3 lateral bunches of setae, 20 palmar and 5 distal setae. Maxilla 1. Left. Palp segment 2 with 5 spine-setae and seta. Outer plate with 10 distal claw-setae with 1-3 distal denticles. Right. Inner plate with 11 setae. Outer plate with 10 serrated claw-setae. Palp segment 2 with 3 apical and 1 distomedial triangular spine-setae and 2 distolateral seta. Maxilla 2 outer and inner plates with numerous plumose setae. Maxillipede. Coxa with 2 lateral setae. Basis with a lateral seta and distal posterior bunch of setae. Basis endite reaches distal margin of merus. Basis endite with long medial setae, short distal plumose setae and 3 distal tooth-like spine-setae. Ischium with posterior distal bunch of setae. Ischium endite oval, large, about as long as and wider than carpus. Ischium endite with short outer setae, long medial setae, 6 tooth-like medial spine-setae, distally transferring into thinner and longer spine-setae and eventually plumose setae. Merus with distal medial bunch of setae. Carpus 1.4 times as long as propodus, with dense posteromedial setae. Propodus 2.1 times as long as dactylus, with 3 medial bunches of setae, part of which plumose, central anterolateral seta and distal anterolateral bunch of setae. Dactylus 2.4 times as long as wide, with distal setae. Dactylar unguis thin and 0.7 times as long as dactylus. Distal margin of coxal plates 1-3 convex. Lateral surface of coxal plate 1 with 1 spine-seta. Coxal plate 2 with 1-2 lateral spine-setae. Coxal plate 3 with 1 lateral spine-seta. Coxal plate 4 distally straight; lateral surface with 1-2 anterior and 4 posterior spine-setae. Gnathopods subequal in size. Gnathopod 1. Basis anterior margin with short setae; posterior margin with numerous long setae. Ischium with bunch of setae. Merus with 2 posterior bunches of setae. Carpus with distal anterior bunch of setae and 2 posteromedial and 1 posterolateral bunches of setae. Propodus almond-shaped, with 4 anteromedial and 4 posteromedial bunches of setae, 1 anterolateral and 1 distal lateral bunch of setae, 2 posterior bunches of spine-seta and setae and distal posterior bunch of 5 spine-setae. Gnathopod 2. Basis anterior margin with numerous long setae and distal short seta; posterior margin with proximal long seta and 6 short setae. Ischium with bunch of setae. Merus with 2 posterior bunches of setae. Carpus with distal anterior bunch of setae, 2 medial bunches of setae and 4 posterior bunches of setae. Propodus slightly wider distally than proximally, with 4 anteromedial, 3 medial, 3 posterior bunches of setae; palmar angle with 5 spine-setae. Pereopods strong. Ischium with 1-2 anterior bunches of setae. Merus and carpus distally wider than proximally. Propodus cylindrical, with distal anterior paradactylar pair of spine-setae. Dactylus with 2 distal anterior and 1 proximal posterior setae. Dactylar unguis strong, about as long as dactylus. Pereopods 3 and 4 subequal, shorter than pereopods 5-7. Basis times as long as wide, with numerous long proximal setae and distal short setae. Merus with distal posterior bunch of spine-seta and setae. Carpus rather short, about half of merus and propodus. Dactylus 0.5 times as long as propodus. Pereopod 3. Merus 1.5 times as long as carpus, with 3 anterior and 1 posterior bunches of setae. Carpus with distal anterior and posterior bunch of setae. Propodus 1.8 times as long carpus, with 2 anterior and 2 posterior bunches of setae. Pereopod 4. Merus 1.5 times as long as carpus; anterior margin with 4 bunches of setae. Carpus anterior margin with distal bunch of setae; posterior margin with distal bunch of spine-seta and setae. Propodus 2.2 times as long as carpus, with 2 anterior and 2 posterior bunches of setae. Pereopods 5-7. Pereopod 5 about as long as pereopod 6 and longer than pereopod 7. Basis times as long as merus; anterior margin with proximal bunch of long setae, median short setae and distal bunch of short setae; posterior surface with lengthwise depression and distolateral prominence. 15

16 Fig. 8 Diagnostic features of Dorogostaiskia parasitica subspecies, A, J, D. p. parasitica, B, G, N, D. p. kamaltynovi subsp. nov., C, M, D. p. hanajevi subsp. nov., D, H, I, K, D. p. ushkaniensis subsp. nov., E, F, L, D. p. stenocephala subsp. nov.: (A-E) dorsal keels of pereonites; (F-H) head and anterior part of body (l, head leangth, h, head height); (I) accessory flagellum, medial view; (J-N) coxal plate 4, lateral view. Scales: A-H, J- N, 1 mm, I, 0.5 mm Distal posterior prominence of pereopod 5 basis longer than prominence of pereopod 6 basis; and prominence of pereopod 6 longer than of pereopod 7. Posterior margin of basis proximally also with triangular lobe, particularly distinct in pereopods 7. Carpus times as long as wide and 0.8 times as long as merus. Propodus 1.4 times as long as merus; posterior margin with 3 bunches of setae. Dactylus times as long as propodus. Pereopod 5. Basis posterior distolateral prominence shorter than ischium, with 5 spine-setae and setae; posterolateral and posteromedial margins with 1 spine-seta. Merus with 2 anterior bunches of setae and 2 posterior bunches of 1-3 spine-setae and setae. Carpus anterior margin with distal bunch of spine-seta and setae; posterior margin with two bunches of 1 and 5 spine-setae. Propodus 4 times as long as wide; anterior margin with subterminal bunch of setae and spine-seta. Pereopod 6. Basis posterior distolateral prominence longer than prominence of pereopod 7, with 3 spine-setae and setae; posteromedial margin with 2 distal spine-setae. Merus anterior margin with 3 bunches of setae, distal bunch also with spine-seta; posterior margin with 2 bunches of 2 and 4 spinesetae and setae. Carpus with proximal seta, distal anterior bunch of 2 spine-setae and setae, proximal 16

17 posterior bunch of spine-seta and seta and distal posterior bunch of 5 spine-setae. Propodus 4 times as long as wide, with 2 anterior bunches of setae, distal of them also with spine-seta. Pereopod 7. Basis posterior margins with setae only; posterior distolateral prominence with 1 spineseta. Merus with 2 anterior bunches of setae and 2 posterior bunches of 1 and 3 spine-setae and setae. Carpus with distal anterior bunch of 3 spine-setae and setae and distal posterior bunch of 3 spine-setae and setae. Propodus 3.5 times as long as wide, with proximal anterior bunch of setae and subterminal anterior bunch of 2 spine-setae and setae. Uropod 1. Peduncle with 3 long posterior spine-setae. Endopod with bunches of long setae and 5 distal spine-setae, one longer than other. Uropod 2 shorter than uropod 1. Peduncle with 1-2 posterior spine-setae. Rami with 4 distal spine-setae. Uropod 3. Peduncle with 1 posterolateral spine seta. Rami with long plumose setae. Exopod 1.8 time as long as peduncle. Endopod slightly shorter than exopod. Variability Body length mm. Dorsal keel of pereonite 1 with 2 or 3 basal anterior spine-setae. Dorsal keel of pleonite 1 with or without dorsal anterior spine-setae. Marginal prominence of pleonite 1 with 2-3 spine-setae. Pleonite 2 with 1-2 marginal spine-setae. Pleonite 3 with 1 or without marginal spineseta. Uronites 2 and 3 with lateral spine-seta in some specimens. Peduncular segment 1 of antenna 1 with anterior spine-setae and 1-2 distal posteromedial spine-setae. Antenna 1 flagellum segmented. Number of spine-setae on coxal plates 1-3: from 0 to 2; in some specimens spine-setae present on one side, but absent on another. Coxal plate 4 with 1-2 anterolateral and 2-4 posterolateral spine-setae. Some specimens from north-west part of Maloe Strait (Capes Aral and Zama) with 3 (2 welldeveloped and 1 rudimentary) segments of accessory flagellum, although in the majority of cases it is 2-segmented with the distal segment being rudimentary. Distribution North-West Baikal: the Olkhon Gates Strait (Proliv Olkhonskie Vorota) and the Maloe More Strait up to Cape Aral in the north, and most probably (by data of Garjajeff, 1901, see below) even to Cape Onguren somewhat further. Habitat and life history Recorded by us on lubomirskiid sponges at depths 7-21 m (down to m in Garjajeff, 1901). Many females have been found with embryos in the beginning of July. Remarks Garjajeff (1901) provided measurements of body length (TL) and antenna 1 length (A1L) for specimens from his sample from Cape Onguren in Northern Baikal. From the A1L:TL ratio (0.9) it seems that these specimens actually were D. p. kamaltynovi. Garjajeff also briefly noted a difference between these and southern specimens in coloration, but did not provide the details. Yampolsky et al. (1994) in turn mentioned that specimens from the Olkhon Strait (i.e. our D. p. kamaltynovi range) were larger than those from SW Baikal, red-greenish in colour and lacking the characteristic blue and yellow spots. Their allozyme data also showed a particular distinction of this Olkhon Strait sample. From our larger collection, we cannot confirm a systematic difference in body length, neither the absence of blue spots in the specimens from Olkhon Strait. Nevertheless, the absence of yellow spots concurs with the current diagnosis between D. p. kamaltynovi and D. p. parasitica. 17

18 Dorogostaiskia parasitica hanajevi Daneliya & Väinölä, subsp. nov. Figs. 3C, 8C, M, 9C Holotype Female, 9.5 mm, partly dissected, appendages mounted on slide: Baikal, near mouth of Kocherikova River [KOC, N basin], dredge from N E to N E, 19 m, sponge, , r/v Titov, st , coll. Daneliya, Väinölä (MZH 53192; slide MZH ). Paratypes [KOC] From the same sample as the holotype: 6 males, 18 females, 9-12 mm (MZH 53193); 1 female (pinned), 8.5 mm (MZH 53198); [KOC], Baikal, by mouth of Kocherikova River (N basin), N E, 6-28 m, sponge, , r/v Titov, st , dive, coll. Khanaev, Daneliya, Väinölä: 2 males, 28 females, mm, and 4 juveniles, 5-6 mm (MZH, 53196); 38, PD (MZH 53197; COI: 37; 28S: 2; GenBank KF586539); [ZAV] Baikal, Zavorotnaya Bay (N basin), N E, 10 m, sponge, , r/v Titov, st a, dive, coll. Khanaev, Väinölä, Daneliya: 1 (MZH 53194); [ZAV] Baikal, Zavorotnaya Bay (N), N E, m, sponge, , r/v Titov, st , dive, coll. Khanaev, Väinölä, Daneliya: 1 female, PD (MZH 53195; COI: 1). Etymology Named for Dr. Igor A. Khanaev, ichthyologist and diver, who organized the sampling of Dorogostaiskia for our study and collected himself most of the material. Diagnosis Head times as high as long, with 4 dorsal spine-setae. Dorsal keels of pereo- and pleonites distally rounded. Antenna 1 clearly shorter than body, 0.7 times as long. Accessory flagellum 3- segmented; segments 1 and 2 equally long, segment 3 rudimentary. Coxal plates 1-3 with 0 to 2 lateral spine-setae; distal margin straight. Coxal plate 4 distal margin deeply concave. Pereopods 5-7 carpus about as long ( ) as merus and times as long as wide. Pereopod 5 posterior distolateral prominence of basis at most as long as ischium. Pereopods 5-6 propodus times as long as wide. Pereopod 7 propodus 5 times as long as wide. Pereopod dactylus times as long as propodus. Color: body light brown with brown to red spots. Body length mm. Comparison Readily differentiated from all other subspecies by shorter antennae 1, which are about 0.7 times as long as body (vs. almost as long as body in other subspecies). In addition, D. p. hanajevi differs from D. p. parasitica by rounded (vs. triangular) dorsal keels and by the absence of golden and blue dorsal spots. From the adjacent, parapatric D. p. kamaltynovi, D. p. hanajevi also differs by the absence of blue dorso-lateral spots, by the straight (vs. convex) distal margins of coxal plates 1-3, but deeply concave (vs. straight) coxal plate 4, and by longer legs (pereopod 5-7 propodus times as long as wide in D. p. kamaltynovi). For differences from other subspecies, see Table 1. 18

19 Molecular diagnosis and variation The subspecies is characterized by a distinct mitochondrial DNA lineage, which differs from other subspecies by 11 % of COI gene nucleotide sites (uncorrected distance), whereas differences within the subspecies are < 2 %. The lineage is typified by the COI GenBank sequence KF (from a paratype MZH 53197, voucher A604, from near the type locality). Description of holotype Body wide, about 3 times as long as wide. Head about 1.5 times as high as long. Head with 2 postrostral, 4 dorsal, 1 lateral and 4-5 marginal spine-setae on low tubercles. Rostrum wide, short, angular. Interantennal blade with smooth lower and upper angles; lower margin parallel to dorsal side of head. Eyes large, convex, oval, 1.3 times as long as wide and 0.3 times as wide as head length. Pereonites and pleonites with high, flat, but not sharp, rounded dorsal keels, slightly directed backwards. Each keel with 3 pairs of spine-setae. Dorsal keel of pereonite 1 and pleonites with a pair of basal anterior spine-setae. Pereonites with high, flat, rounded marginal keels, bearing 1 line of up to 6 spine-setae and 1 basal posterior spine-seta. Pleonites with 1 posterolateral spine-seta. Pleonite 1 with 2 marginal spine-setae on low prominence. Pleonite 2 with 1 marginal spine-seta. Pleonite 3 without marginal spine-setae. Uronites smooth, with rare setae. Epimera distally rounded, with rare setae. Epimeron 1 shorter than epimeron 2 and 3. Epimeron 1 and 2 with transverse rib. Telson about as long as uronite 3, bilobate; each lobe with 1-2 dorsomedial and 3-4 long apical setae. Antenna 1 is 0.7 times as long as body and 2.3 times as long as antenna 2, with setae about twice as long as width of segments. Peduncular segment 1 is 1.2 times as long as segment 2, with proximal anterolateral tubercle, anterior irregularly set spine-setae and 1 posterior distomedial spine-seta. Peduncular segment 2 about as long as segment 3, with 4 groups of setae. Peduncular segment 3 with 4 groups of setae. Accessory flagellum 3-segmented; segment 2 as long as segment 1, segment 3 rudimentary. Flagellum segmented; proximal segments with bunches of long setae; distal segments with short setae. Antenna 2 with long setae, up to 3 times as long as width of segments. Conus about as long as peduncular segment 3. Peduncle segment 4 is 1.1 times as long as segment 5, with 3 anteromedial and 4 posterolateral bunches of setae. Peduncle segment 5 with 3 medial and 3 posterolateral bunches of setae. Flagellum 8-segmented. Flagellar segments with multiple distal dorsal, ventral and medial setae. Mandible. Incisors with 5 cusps. Right lacinia mobilis bifurcate; lower spine distally flattened, with 6 terminal denticles. Left lacinia mobilis with 4 cusps. Inner margin with a row of 6 finely serrated spine-setae and plumose setae between them. Palp segment 2 is times as long as segment 3, with posterior setae. Palp segment 3 with 4 medial and 3 lateral bunches of setae, palmar and 5-7 apical setae. Maxilla 1. Left. Inner plate with 12 plumose setae. Outer plate with 10 distal strong claw-setae with 13 distal denticles. Palp segment 2 with 3 spine-setae and 2 outer robust setae. Maxilla 2 outer and inner plates with numerous plumose setae. Maxillipede. Coxa with 2 distal posterior setae. Basis with lateral seta and distal posterior bunch of setae. Basis endite reaches distal margin of merus. Basis endite with long medial setae, short distal plumose setae and 3 distal tooth-like spine-setae. Ischium with posterior distal bunch of setae. Ischium endite oval, large, about as long as and wider than carpus. Ischium endite with short outer setae, long medial setae, 6 tooth-like medial spine-setae, distally transferring into thinner and longer spine-setae and eventually plumose setae. Merus with distal medial bunch of setae. Carpus 1.3 times as long as propodus, with dense posteromedial setae. Propodus 2.3 times as long as dactylus, with 3 medial bunches of setae, part of which plumose, central anterolateral seta and distal anterolateral bunch of setae. Dactylus 2.6 times as long as wide, with distal setae. Dactylar unguis thin and 0.7 times as long as dactylus. Coxal plates 1-3 with straight distal margin. Coxal plate 1 with 1 lateral spine-seta. Coxal plate 2 with or without lateral spine-seta. Coxal plate 3 with lateral spine-seta. Coxal plate 4 distally deeply concave, with advanced anterodistal angle; laterally with 2 spine-setae. 19