A revision of Eogammarus Birstein, 1933 (Crustacea, Amphipoda, Anisogammaridae), with a description of a new species Author Tomikawa, Ko Author Morino, Hiroshi Author Toft, Jason Author Mawatari, Shunsuke F. text Journal of Natural History 2006 J. Nat. Hist. 2006-08-28 40 17 - 18 1083 1148 http://dx.doi.org/10.1080/00222930600828859 journal article 10.1080/00222930600828859 1464-5262 10092125 41F5583D-BD6D-4FFF-961F-39AA6A6ECCE8 Eogammarus barbatus ( Tzvetkova, 1965 ) [Japanese name: Kebuka togeo yokoebi, new] ( Figures 5–8 ) Anisogammarus ( Eogammarus ) barbatus Tzvetkova 1965 , p 351 , Figure 1 ; 1972, p 214; 1975, p 121–125, Figures 46, 47. Eogammarus barbatus : Bousfield 1979 , p 314 . Material examined Japan . „ , 20.2 mm , ♀ , 17.1 mm , Makinouchi (43 ° 219350N, 145 ° 379430E), Nemuro City, Hokkaido , 25 April 2003 , collected by K. Tomikawa. 3 „ , 17.5–24.9 mm , Shiraoi River (42 ° 339380N, 141 ° 199450E), Shiraoi Town , Shiraoi County , Hokkaido , 22 February 1990 , collected by K. Kuribayashi. Russia . „ , 19.0 mm, Achomten Bay , Kamchatka , 19 August 1933 , collected by N. Spasskii. „ , 16.5 mm , CMNC 1980-0134 , Antonova, 2 km from mouth of stream, Sakhalin Island, 4 October 1966 , collected by V . A. Kudrjaschov. ♀ , 12.5 mm , CMNC 2004-1025 , De-Kastri Bay , 19 August 1948 , collected by O. B. Mokijewsky. Description of male ( 20.2 mm from Makinouchi) Antenna 1 ( Figure 5A ): peduncular articles 1:2: 3 in ratio of 1.0:0.9:0.5; article 1 with robust seta posterodistally, posterior margin with two pairs and four clusters of setae and a single seta; posterior margin of article 2 with two pairs and four clusters of setae; posterior margin of article 3 with two pairs and cluster of setae; accessory flagellum seven-articulate; primary flagellum 29-articulate, each article with one short aesthetasc ( Figure 5B ). Antenna 2 ( Figure 5C ): 0.8× length of antenna 1; peduncular article 1 with apical setae; articles 4 and 5 about equal in length; posterior margin of article 4 with five clusters of setae; posterior margin of article 5 with six clusters of setae; flagellum 15-articulate, with cup-calceoli ( Figure 5D ). Pleon : smooth. Mandible ( Figure 5G, H ): palp article 2 with 19 marginal and 30 submarginal setae; palp article 3 as long as article 2 length, with three clusters of A-setae, pair of B-setae, and a single B-seta. Maxilla 1 ( Figure 5I ): inner plate with 22 plumose setae; palp article 1 with three setae on outer margin, article 2 with six setae on outer margin and seven stout and five slender setae apically. Maxilla 2 ( Figure 5J ): inner plate with 19 facial setae. Maxilliped ( Figure 5K–M ): inner plate with three apical and two medial bent, stout setae; outer plate beyond middle of palp article 2; outer distal corner of palp article 2 with cluster of setae. Figure 5. Eogammarus barbatus ( Tzvetkova, 1965 ) , Makinouchi, Nemuro, Japan, male, 20.2 mm. (A) Antenna 1; (B) flagellar article of antenna 1 (some setae are omitted); (C) antenna 2; (D) flagellar article of antenna 2 (some setae are omitted); (E) upper lip; (F) lower lip; (G) left mandible; (H) incisor and lacinia mobilis of right mandible; (I) maxilla 1 (robust apical setae on outer plate are shown enlarged); (J) maxilla 2; (K) palp of maxilliped; (L) inner plate of maxilliped; (M) outer plate of maxilliped; (N) gnathopod 1; (O) dactylus of gnathopod 1; (P) palm of gnathopod 1 (slender setae are omitted); (Q) gnathopod 2; (R) dactylus of gnathopod 2; (S) palm of gnathopod 2 (slender setae are omitted). Scale bars: 0.1 mm. Figure 6. Eogammarus barbatus ( Tzvetkova, 1965 ) , Makinouchi, Nemuro, Japan, male, 20.2 mm. (A, B) Pereopods 3 and 4; (C–E) coxa–ischium of pereopods 5–7; (F) pleopod 1 (plumose setae on rami are omitted); (G) retinacula of pleopod 1; (H) clothespin seta; (I–K) dorsal margins of urosomites 1–3; (L–N) epimeral plates 1– 3. Scale bars: 0.1 mm. Figure 7. Eogammarus barbatus ( Tzvetkova, 1965 ) , Makinouchi, Nemuro, Japan, male, 20.2 mm. (A–C) Uropods 1–3; (D) telson (dorsal view). Scale bars: 0.1 mm. Gnathopod 1 ( Figure 5N ): palmar margin of propodus ( Figure 5P ) lined with 11 inner and six outer robust striated peg setae. Gnathopod 2 ( Figure 5Q ): palmar margin of propodus ( Figure 5S ) lined with 10 inner and eight outer robust striated peg setae, inner stiff pectinate seta. Pereopods 3–4 ( Figure 6A, B ): basis with setose anterior and posterior margins; merus, carpus, and propodus length ratio 1.0:0.9:0.9 for pereopod 3, 1.0:0.9:1.0 for pereopod 4. Pereopod 5 ( Figure 6C ): inner posterodistal part of basis with robust seta. Pereopod 6 ( Figure 6D ): longest posteromarginal seta of basis 0.8× width of ischium. Pereopod 7 ( Figure 6E ): posterodistal margin with robust seta. Pleopods ( Figure 6F–H ): retinacula paired ( Figure 6G ). Epimera 1–3 ( Figure 6L–N ): with setose anteroventral margins. Uropod 1 ( Figure 7A ): inner ramus length 0.8×, outer ramus length 0.7× peduncle length; peduncle with robust marginal setae and slender basofacial seta; inner ramus with two robust inner marginal setae; outer ramus with one inner and one outer robust marginal setae. Uropod 2 ( Figure 7B ): inner ramus length 0.9× and outer 0.7× peduncle length; peduncle with robust marginal setae; inner ramus with two robust inner marginal setae; outer ramus with a robust outer marginal seta. Uropod 3 ( Figure 7C ): inner ramus length 0.2× outer ramus length, with plumose setae; outer margin of outer ramus with five clusters of robust setae and slender simple setae; terminal article length 0.1× proximal article length. Telson ( Figure 7D ): length 1.1× width, with robust apical and distolateral setae, slender apical and distolateral setae, and apical and distolateral penicillate setae; robust apical setae longer than slender setae; cleft 62%. Figure 8. Eogammarus barbatus ( Tzvetkova, 1965 ) , Makinouchi, Nemuro, Japan, female, 17.1 mm. (A) Antenna 1; (B) antenna 2; (C) gnathopod 1; (D) dactylus of gnathopod 1; (E) palm of gnathopod 1 (slender setae are omitted); (F) gnathopod 2; (G) dactylus of gnathopod 2; (H) palm of gnathopod 2 (slender setae are omitted); (I) brood plate of gnathopod 2; (J–L) coxa–ischium of pereopods 5–7; (M) uropod 3. Scale bars: 0.1 mm. Description of female ( 17.1 mm from Makinouchi) Antenna 1 ( Figure 8A ): accessory flagellum six-articulate; primary flagellum 37-articulate, each article with one short aesthetasc. Antenna 2 ( Figure 8B ): peduncular article 4 about as long as article 5; article 4 with five clusters of posteromarginal setae; article 5 posterior margin with one pair and four clusters of setae; flagellum 11-articulate, with cup-calceoli. Gnathopod 1 ( Figure 8C ): inner face of coxa strongly setose; palmar margin of propodus ( Figure 8E ) with 15 robust simple setae on inner distal part. Gnathopod 2 ( Figure 8F ): palmar margin of propodus ( Figure 8H ) with two simple and five robust pectinate setae on inner distal part. Pereopod 6 ( Figure 8K ): longest posteromarginal seta of basis 0.5× width of ischium. Pereopod 7 ( Figure 8L ): longest posteromarginal seta of basis 1.0× width of ischium. Uropod 3 ( Figure 8M ): outer margin of outer ramus with six clusters of robust setae, inner margin with five clusters of robust setae. Variation The number of clusters of setae on peduncular articles of both antennae 1 and 2 varies from four to six. The number of clusters of robust setae on the outer margin of the outer ramus of uropod 3 varies from four to six. The telson is as long as wide in some specimens. Remarks Eogammarus barbatus is closely similar to E. itotomikoae . Diagnostic characters between the two species are mentioned in the remarks for E. itotomikoae (see above). Distribution Hokkaido, Kamchatka , Sakhalin , Shakotan Island ( Kuril Islands ), Udskaya Gulf ( Sea of Okhotsk coast of Russia ) . Habitat River mouth.