Neopleustes carinatus Margulis 1963
Creators: name: Labay, Vjacheslav S.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Pleustidae
Neopleustes
Neopleustes carinatus

description: Neopleustes carinatus Margulis, 1963
Figures 1c, 2c, j, q, y, 3b, 4c, 5c, 14–17, 22
Neopleustes carinatus Margulis, 1963: 168–169, fig. 3.— Kudrjashov 1968: 94.— Barnard & Karaman 1991: 649.— Hendrycks & Bousfield 2004: 94.— Dzhurinskyi 2013: 135.
The species was very briefly described by Margulis (1963) on 10 specimens from the north-eastern part of the Sea of Okhotsk without an exact indication of localization. A full description of the species is given below on the specimens from the author’s collection to fill the existing gaps.
Diagnosis. Female (11.4 mm). Body, pereon segments 1–7 and pleon segments 1 and 2 without carination, pleon segment 3 with sloping low ridge dorsally. Cephalon, pereonal and pleonal segments with submedial and sublateral groups of simple aesthetascs dorsally.
Head without anterodorsal crest. Rostrum small, about 0.2 times as long as peduncular segment 1 of antenna 1, apex acute; anterior head lobe rounded, lateral cephalic lobe deeply recessed sinus, anteroventral corner acute. Eye large, broadly reniform, light brown, with light edging. Antenna 1 destructed; peduncular segment 1 elongate and strong, 1.8 times as long as segment 2.
Upper lip apically bilobate and asymmetrical. Lower lip, outer lobes oblique elliptical, widely spread. Mandible, molar weak, covered microsetae, without triturative surface and without a medial molar seta; incisor margins with 7–9 teeth; left lacinia 10-dentate, right lacinia absent; accesory spine rows with 8–9 raker setae; palp very large; palp segment 3 is 1.2 times longer than segment 2, inner margin lined with 11–13 strong pectinate D setae, apex with 2 long pectinate and with 2 medium simple E setae; segment 2, inner margin lined with simple setae; segment 1 without setae. Maxilla 1, inner plate with single plumose apical seta; outer plate with 9 slender pectinate setae (spine-like setae); palp extending beyond outer plate, apex oblique, with a row of 7–8 cuspidate setae (Watling, 1989: type IIA3) and with a subapical row of 6 thin setae. Maxilla 2, inner plate slightly shorter and broader than outer plate; inner margin with single strong plumose seta. Maxilliped, inner plate short, reaching basal article of palp, apex subtruncate, with 7 button setae (Watling, 1989: type IIA43) and with two cuspidate setae; outer plate short, reaching about 1/3x length of palp segment 2, apex narrowly subtruncate, inner margin with a row of numerous setae; palp narrow, segment 2 subequal in legth to segment 3; dactylus slender, slightly curved and slightly shorter than palp segment 3, the distal process of palp segment 3 present, buy not conspicuous.
Coxal plates 1–3 posteroventrally with single tooth, lower margins rounded; coxal plate 4 much broader, deeply excavated posteroproximally, rounded below; coxal plates 5–6 broadly posterolobate, posteriorly roundly subquadrate, posterior lobe with numerous short simple setae ventrally; coxal plate 7 with oblique anterior margin, rounded posteroventrally. Coxal gills 2–6, relatively small, sac-like.
Pereopods 1 and 2 (gnathopods 1 and 2) small, weakly subchelate and subsimilar. Pereopod 1, basis with a dense row of anterior setae, carpus long, about 0.87 times as long as propodus, posterior lobe broad, shallow; propodus narrow, with oblique palmar margin, with small mid-palmar tooth, palmar margin with 2 clusters of spine-like setae posteriorly; posterior margin with 4–5 groups of setae. Pereopod 2, basis with a rare anterior row of short setae, merus without posterodistal tooth, carpus long, about 0.69 times as long as propodus, carpal lobe as in pereopod 1, palmar margin with medial tooth and with 2 clusters of strong posterodistal spineformes setae, posterior margin with 6 transversal setae clusters. Pereopods 3–4 medium strong; basis linear, with dense row of short setae along anterior margin; merus anterodistally produced, acute; carpus 1.4 times shorter than merus, posterior margin with 3–4 groups of strong spine-like setae; propodus 1.25–1.4 times as long as carpus, posterior margin with 6–7 groups of strong spine-like setae; dactylus slender, 0.55 times as long as propodus. Pereopods 5–7 closely homopodous in form and size; bases with posterior rounded wing; merus posterodistally produced, acute, anterior margin with 5–6 groups of strong spine-like setae, posterior margin with 5 groups of strong setae; carpus 1.3 times shorter than merus, anterior margin with 4 groups of strong spine-like setae; propodus 1.3 times as long as carpus, anterior margin with 5 groups of strong spine-like setae; dactylus medium in length, 0.52–0.55 times as long as propodus.
Epimeral plates 1–3, lower margin with short spine-like setae, posteroventral corners subacute, slightly produced in plate 1, posterior margin without serration. Pleopods regular, coupling basis of inner ramus with 7 specific stout two-pointed plumose setae along inner margin.
Uropod 1, peduncle subequal to outer ramus in length; outer ramus the shorter; margins of peduncle and rami with serially arranged short spine-like setae. Uropod 2, inner ramus 1.7 times as long as peduncle, outer ramus the shorter, 0.67 times as long as inner. Uropod 3, inner ramus 3 times as long as peduncle, with a row of 9–10 small spine-shaped setae along lateral and medial margins each, with acute and non-spinose apex; outer ramus about 0.56 times as long as inner; outer ramus with a row of 4 small spine-shaped setae along lateral and medial margins each, with acute and non-spinose apex. Telson linguiform, apically rounded, length about 1.53x width, with proximal ventral keel, with lateral paired short setae.
Male: unknown.
Material. Female, 11.4 mm, Х 53865 /Cr-2410, Sea of Okhotsk, Far East of Russia (52.15368898° N 143.8973123° E, 60 m), coarse sand, 23 July 2019. 1 female, 8.4 mm, Х 53866 /Cr-2411, Sea of Okhotsk, Far East of Russia (52.16004338° N 143.886981° E, 61.6 m), coarse sand, 27 June 2019; 1 female, 4.9 mm, Х 53867 /Cr-2412, Sea of Okhotsk, Far East of Russia (52.16004338° N 143.886981° E, 61.6 m), coarse sand, 27 June 2019.
Type locality. Sea of Okhotsk, without indicating the exact location (Margulis 1963).
Ecology: N. carinatus was found in the depth interval from 7 (Margulis 1963) to 62 m (own data) on the rocks, stones, pebbles and coarse sand. Females with developed marsupium was found in July.
Distribution: The shelf of Sea of Okhotsk.
Remarks. N. carinatus differs from other species of the genus Neopleustes by the absence of distinct dorsal teeth on pereon and epimeron (Figs. 1c, 14a).
description: Published as part of Labay, Vjacheslav S., 2021, Review of amphipods of the family Pleustidae Buchholz, 1874 (Crustacea Amphipoda) from the coastal waters of Sakhalin Island (Far East of Russia). I. Subfamily Neopleustinae Bousfield & Hendrycks, 1994, pp. 267-306 in Zootaxa 4974 (2) on pages 290-295, DOI: 10.11646/zootaxa.4974.2.3, http://zenodo.org/record/4775545