Published December 31, 2010 | Version v1
Taxonomic treatment Open

Odius cassigerus subsp. ochoticus Labay, 2010, subsp. n.

Description

Odius cassigerus ochoticus, subsp. n.

Figs. 5–8

Material. Holotype: Okhotsk Sea, 12 Aug. 2007, 54°82'N, 144°43'E, 200 m, female, length 16 mm. Collection of a Museum of Marine Biology Institute, Vladivostok: N 18861. Paratype: 1 male, length 8 mm. Collection of a Museum of Marine Biology Institute, Vladivostok: N 18861.

Diagnosis. Body with dorsal carination on pereonites 1–4 and with distinct teeth on pereonites 5–7 and on all plronites. Lower corner of cephalon subrectangular. Epimeral plate 3 with obtuse tooth medially. Posterior margin of bases of pereopods 5–7 with large triangular teeth in distal part. Maxilla 1 palp 1-articulate, short, about 1/5 of the outer plate length; with one setae on the distal margin. Maxilliped palp 4-articulate. Carpus lobe of preopod 2 (gnathopod 2) exceeding 1/2 of propodus length. Telson cleft 1/7.

Description. Body with dorsal carination on pereonits 1–4, with distinct teeth on pereonits 5–7 and on all pleonites (fig. 5). Sculpture of cover with large punctuation. Rostrum well-developed, reaching ½ of peduncle article 2 antenna 1 length. Lower corner of cephalon subrectangular. Pereonite 1 forming a sharp visor on an anterior margin that covers a posterior part of cephalon. Coxa 1–3 long, slightly curved anteriorly (fig. 7a,c.e). Coxa 1 rounded, pointed distally. Coxa 2 with smoothly rounded right angle anterodistally. Coxa 3 with acute angle anterodistally. Coxa 4 excavated with obtuse posterodistal angle (fig. 7f). Coxa 5–7 with processed posterior lobe. Eye medium size, long reniform, about 1/3 of the head height. Antenna 1 no longer than antenna 2; accessory flagellum lacking; flagellum with numerous short sensory setae along lower margin (fig. 6a). Antenna 2 with short flagellum which is slightly longer than last peduncle article (fig. 6b).

Mandible narrow conical, claw shaped; incisor multidentate, accessory plate present on left side; molar prominent, setose; short spine and setae row present between incisor and molar (fig. 6d,e). Palp of mandible 3-articulate; articles 2 slightly longer than 3; article 3 with a row of two-claw spines, distally with two oar shaped spines. Lower lip notched along midline; apices narrow pointed, without setation (fig. 6f). Maxilla 1 with short 1-articulate palp, about 1/5 of the outer plate length and carrying one setae distally (fig. 6g,h). Outer plate narrow, pointed, carrying short, heavy bidentate spines distally, densely setose proximally. Inner plate short, about ½ length of the outer plate, with 2 plumose setae distally. Maxilla 2 outer plate narrower than inner; setae on outer plate subequal to those on inner (fig. 6i). Maxilliped palp 4-articulate; article 2 slightly expanded medially; article 4 long (fig. 6j).

Pereopod 1 (gnathopod 1) chelate (fig. 7b). Anterior margin of basis with a row of setae; posterior margin prominent with out setae. Propodus slightly shorter than carpus; palm of propodus forming chela, with distinct finger, distally with short spine. Base of dactylus with two strong ridge setae.

Pereopod 2 (gnathopod 2) (fig. 7d). Basis elongate; posterior margin prominent, distally with few spines; anterior margin with a row of setae. Merus with processed lobe; border with stout setae. Carpus short; with distinct lobe that is a little more than 1/2 of propodus length; lobe and inner margin armed a row of strong plumose setae. Propodus expanded distally, strong; palm toothed, with two spines at palm angle. Dactylus slightly shorter than propodus palm, two-claw.

Pereopods 3–4 (fig. 7e,g). Basis elongate; anterior margin concave, with numerous setae; posterior margin curved. Merus slightly longer than carpus, with distinct acute lobe at the anterior distal angle. Carpus about 0.6 times as long as propodus; with 2–3 groups of small spines along posterior margin. Propodus linear; armed 6-7 small spines along posterior margin. Dactylus about ½ as long as propodus.

Pereopod 5–7 (fig. 7h-j): basis with distinct hind distal rounded lobe; posterior margin with large triangular teeth in distal part; wing of base separated with curved crest; anterior margin armed a row of setae. Merus produced distally, posterior long acute lobe, as long as carpus; posterior margin bearing 4–6 small spines. Carpus about 0.5–0.6 times as long as propodus. Propodus linear, armed 4 spines along anterior margin. Dactylus short, about 1/3 as long as propodus.

Epimeral plate 1: posterior margin slightly excavate (fig. 8a). Epimeral plate 2 with oblique crest; posteroventral corner pointed; posterior margin with obtuse tooth (fig. 8b). Epimeral plate 3: posteroventral corner angularly rounded; posterior margin with obtuse tooth medially (fig. 8c).

Pleopods normal (fig. 8d). Peduncle with two specific toothed coupling spines on the inner corner. Basis of inner ramus with a row of specific stout two-pointed plumose setae along inner margin (fig. 8e-g).

Length of uropods 1–3 decreases from 1 to 2; 2 and 3 subequel. Peduncle margins of uropod 1 armed numerous spines proximally (fig. 8h). Inner ramus subequal to outer; both with numerous spines along posterior margin. Uropod 2 peduncle with numerous spines along borders (fig. 8i). Inner ramus about 0.7 as long as outer ramus, both with 7 spines along posterior margin. Uropod 3 peduncle subequel to inner ramus (fig. 8j). Inner ramus about ½ as long as outer ramus, lanceolate, with few small spines along hind margin. Outer ramus with numerous spines along posterior margin.

Telson longer than wide, cleft 1/7 (fig. 8k).

Remarks. The nominal subspecies Odius cassigerus cassigerus Gurjanova, 1972 was originally described from the south outlying part of Okhotsk Sea near south Kuril Islands. In Gurjanova´s (1972) there was an error: in the legends of plates 42 and 43 the type locality is given as Tatarsk Strait (Sea of Japan); in the descriptive text, however, the south part of Okhotsk Sea (44°49'N, 144°26'E) is given as the type locality. The author has found this nominal subspecies also in a southern part of Okhotsk Sea in Aniva bay. Odius cassigerus cassigerus Gurjanova, 1972 has the granulated sculpture of covers. Rostrum straight. Pereonite 1 anterodorsally with peak which covers a posterior part of head. Lower corner of cephalon forming acute angle. Coxa 2 rounded anterodistally. Posterior margin of epimeral plate 3 with distinct acute upwards curved tooth. Odius cassigerus ochoticus subsp. n. was found in the north-west part of Okhotsk Sea (54°82'N, 144°43'E). This subspecies differs from the nominative subspecies by a head shape: lower corner of cephalon subrectangular. Coxa 2 has smoothly rounded right angle anterodistally. Epimeral plate 3 has obtuse tooth medially. Sculpture of cover with large punctuation.

Other

Published as part of Labay, Vjacheslav S., 2010, A new species and subspecies of Ochlesidae Stebbing, 1910 (Amphipoda: Gammaridea) from the Okhotsk Sea, pp. 35-44 in Zootaxa 2354 on pages 40-43, DOI: 10.5281/zenodo.193532

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Linked records

Additional details

Biodiversity

Family
Odiidae
Genus
Odius
Kingdom
Animalia
Order
Amphipoda
Phylum
Arthropoda
Species
ochoticus
Taxonomic status
subsp. nov.
Taxon rank
subSpecies
Taxonomic concept label
Odius cassigerus subsp. ochoticus Labay, 2010

References

  • Gurjanova, E. F. (1972) New species of Amphipoda (Amphipoda, Gammaridea) from a northwest part of Pacific ocean and high Arctic regions. Trudy Zoologicheskogo instituta AN SSSR, 52, 129 - 200. [in Russian].