Bathycopea dicarina Shimomura, 2008, sp. nov.
Creators: name: Shimomura, Michitaka
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Ancinidae
Bathycopea
Bathycopea dicarina

description: Bathycopea dicarina sp. nov.
Figs 8–13
Material examined. Holotype. Male, 4.1 mm (KMNH IvR 700,255), dissected and mounted on glass slides, RV Tansei-maru, St. BT-1, Tosa Bay, Kochi Prefecture, 33º11.1’N, 133º40.1’E- 33º11.9’N, 133º41.0’E, 518– 522 m, 3 m ORE beam trawl, 25 June, 2000, collected by Dr. T. Akiyama.
Paratypes. 2 males, 4.0 mm (KMNH IvR 700,256), dissected and mounted on aluminum holders for a SEM observation, 4.4 mm (KMNH IvR 700,257), non-ovig. female, 2.6 mm (KMNH IvR 700, 258), whole specimens in glass bottle, same data as holotype; male, 4.2 mm (KMNH IvR 700,259), non-ovig. female, paratype, 4.3 mm (KMNH IvR 700,260), dissected and mounted on glass slides, RV Tansei-maru, St. EN-5, Enshu-nada, Shizuoka Prefecture, 34.05º42.80’N, 137º57.28.70’E-34.04º66.70’N, 137º56.30.80’E, 952–1060 m, 3 m ORE beam trawl, 3 May, 2004, collected by Dr. T. Akiyama.
Diagnosis. Body dorsally smooth. Pereonites 1 to 7 increasing in width posteriorly, without dorsal keels. Pereonite 2 anterior-laterally projected: lateral projection broad. Pleonite 1 tapering laterally, slightly arched dorsally. Pleotelson gradually decreasing in width posteriorly, with double carina dorsally. Eye lobes rudimentary, without ommatidia. Epistome apically pointed, narrow, reaching to frontal margin of antennule peduncular article 1; margins curved laterally. Uropod moderately narrow, about 7.5 times as long as width, without large serrations on lateral margin. Pereopod 1: distal corner of carpus pointed. Pereopod 2 in male: merus and carpus slightly longer than ischium; propodus about 1.2 times as long as carpus, nearly straight, without proximal projection, with 5 robust sensory setae and some simple scales ventrally; dactylus slender, about 0.7 times as long as propodus, curved inward, with few apical short simple setae.
Description of the holotype male. Body (Fig. 8 A, B) about 1.5 times as long as maximum width. Head (Fig. 8 A) fused with pereonite 1 at middle. Pleon (Fig. 8 A) slightly broader than pereonite 7; dorsum nearly flattened. Pleotelson (Fig. 8 A, B) about 1.6 times as broad as long, apically rounded; dorsum arched. Uropodal sympod with protuberance dorsal-proximally; endopod (Fig. 8 A) marginally crenulated, with many short setae laterally and short tooth distal-medially.
Antennule (Fig. 8 A, D): peduncular article 1 dorsally with few short setae and many simple scales, ridged distal-dorsally; article 2 about 0.8 times as long as article 1; article 3 longest, with some short medial and long distal setae. Flagellum consisting of 10 articles: article 1 minute; article 2 slightly shorter than peduncular article 2, with 2 medial setae; article 3 half as long as article 2, with 2 distal setae; article 4 slightly longer than article 3, with 2 medial and dorsal short setae; article 5 as long as article 4, with 3 medial fringed setae and 1 dorsal simple seta, and with 2 long simple setae and 1 long aesthetasc distally; article 6 shorter than article 5, distally with 2 long and 1 short simple setae, and 2 long aesthetascs; articles 7 to 10 decreasing in width, each with some simple setae and long aesthetascs distally.
Antenna (Fig. 8 C, E): peduncular article 2 with many medial and 1 lateral setae; article 3 longest and widest, with many medial and lateral fringe setae, and simple scales; article 4 as long as article 2, with many medial and lateral fringe setae, and simple scales. Flagellum consisting of 10 articles: article 1 slightly longer than peduncular article 4, with many medial and few lateral fringe setae, and many simple scales; article 2 to 10 decreasing in length and width, each with some fringe and simple setae.
Left mandible (Fig. 8 F): article 1 of palp robust, with 1 distal seta; article 2 longest, about 1.4 times as long as article 1, with 5 pectinate setae and few simple scales; article 3 about half as long as article 2, with 7 pectinate setae. Incisor slender, with 3 teeth; lacinia mobilis with 3 teeth; setal row with robust setae. Right mandible (Fig. 8 G): article 1 of palp with some setulated scales, without setae; article 2 with 1 simple short seta and 3 pectinate setae, and some setulated scales; article 3 with 5 pectinate setae.
Maxillule (Fig. 8 H) with inner lobe bearing 1 apical long seta; outer lobe with 6 apical robust setae and few setulated scales.
Maxilla (Fig. 8 I) with inner lobe bearing 3 apical robust setae; medial lobe with 6 apical pectinate setae; outer lobe with 4 apical robust setae.
Maxilliped (Fig. 9 A): article 1 with 1 ventral seta and few simple scales; article 2 trapezoidal, twice as long as article 1, with 2 medial and 1 ventral setae, and 8 simple and 6 setulated scales; article 3 as long as article 2, with 2 medial setae and 11 setulated scales; article 4 narrow, slightly shorter than article 3, with 2 distal-medial setae, and 8 setulated scales; article 5 minute, with 4 apical long setae and 4 setulated scales; endite trapezoidal, bearing many fine marginal setae, with many setulated and simple scales ventrally, and coupling hook medially.
Pereopod 1 (Fig. 8 J): basis robust, ventrally setulose; ischium about 0.7 times as long as basis, without setae; merus trapezoidal, about 0.8 times as long as ischium, without setae; carpus shorter than merus, without distal setae; propodus with row of triangulate fringes on palm, proximal-medially with some setulated and simple scales; dactylus stylet-like, with 2 blunt teeth proximal-ventrally, reaching to carpus, without setae.
Pereopod 2 (Fig. 8 K) with many simple scales; ischium about 0.4 times as long as basis, with some short simple setae and few simple scales ventrally; merus as long as ischium, ventrally setulose, with long simple seta and some simple scales ventrally and simple seta distal-dorsally; carpus slightly longer than merus, ventrally setulose, with 2 simple setae and some simple scales ventrally; propodus longer than carpus, with 5 robust sensory setae and some simple scales ventrally, with long simple seta ventral-distally and 4 long simple setae dorsal-distally; dactylus slender, shorter than propodus, curved inward, with 2 apical short simple setae.
Pereopod 7 (Fig. 8 L): basis longest article, unarmed; ischium 1/3 longer than basis, unarmed; merus about 1.5 times as long as ischium, with long and short setae distal-ventrally and 2 long setae distal-dorsally; carpus longer than merus, with long and short setae distal-ventrally, and 2 short setae ventrally, and with long seta distal-dorsally; propodus shorter than carpus, with 2 distal-ventral, 1 ventral, 3 distal-dorsal long setae and 2 dorsal short setae; dactylus narrowest article; distally with 2 short setae and unguis
Pleopod 1 (Fig. 9 B) with many simple scales ventrally: peduncle about 3.3 times as broad as long, with 3 coupling hooks distal-medially and many fine setae medially, and many short setae laterally; endopod subtriangulate, about 2.6 times as long as peduncle, slightly broader than long, bearing many long plumose and fine simple setae; exopod as broad as endopod, longer than endopod, with many long plumose and many fine setae marginally and few simple short setae ventrally.
Pleopod 2 (Fig. 9 C) with many simple scales ventrally: peduncle about 2.4 times as broad as long, with 3 coupling hooks distal-medially and many fine setae marginally; endopod broad, trapezoidal, about 2.1 times as long as broad, 4.1 times as long as peduncle, bearing some long plumose and fine simple setae; appendix masculina as long as endopod, with fine setae proximal-ventrally; exopod ovate, about 0.7 times as long and about 0.8 times as wide as endopod, with many long plumose and fine setae marginally.
Pleopod 3 (Fig. 9 D) with some simple scales ventrally on peduncle and exopod: peduncle longer than those of pleopods 1 and 2, about 2.2 times as broad as long, with 3 coupling hooks distal-medially and many fine short setae medially; endopod broad, about 2.5 times as long as peduncle, longer than broad, bearing 4 short plumose setae and short simple seta apically; exopod articulated, bearing many plumose setae.
Pleopod 4 (Fig. 9 E): endopod as long as exopod, tapering to apex, with 1 simple seta apically; exopod similar to endopod in shape, about 2.1 times as long as broad, bearing 6 simple setae laterally.
Pleopod 5 (Fig. 9 F): endopod about 2.3 times as long as broad, with 3 shallow notches proximal-medially and many fine setae distal-medially; exopod longer than endopod, with 6 scale patches medially, 7 short simple setae laterally and many fine setae distal-medially.
Additional notes on paratype. One paratype male was observed with SEM (Figs. 10–13).
Body (Fig. 10 A–D) setation scattered. Dorsal seta (Fig. 10 F) on pereonite 5 branched, arising from shallow pit; dorsal seta (Fig. 11 A) on pleon strongly curved inward, with broad membranaceous fringe. Marginal setae on uropods (Fig. 10 E) penicillate. Antennule peduncular articles 1 (Fig. 11 B) ridged distal-dorsally. Setae on medial margin of antenna (Fig. 11 C) with many fine setae on half of its base. Incisors of mandibles (Fig. 11 D, E) with many setulated scales. Mandibular palp (Fig. 11 F): article 2 with many simple scales, marginally setulated; article 3 distally truncate, without scales. Maxilliped palp (Fig. 12 A): articles 2–4 with many scales bearing long fine setae; article 5 without scales. Pereopod 1 (Fig. 12 B, C, D): palm of propodus with rows of 18 short setae and triangulate fringes; dactylus without rudimentary unguis; scales of propodus simple, agglutinated on basis. Pereopod 2 (Fig. 12 F): propodus with many simple scales medially and setulated scales on palm; dactylus with few short setae subdistally and setulated scales proximally. Pereopod 3 (Fig. 12 E): scales on merus and propodus simple medially, setulated on marginal ridge. Pleopod 1 (Fig. 13 A): scales rudimentary, simple. Pleopod 5 (Fig. 13 B) with scale patch having curved setulated scales.
Remarks. Bathycopea dicarina sp. nov. is similar to B. typhlops in having pereonites increasing in width posteriorly, eye lobes rudimentary, moderately slender uropod, and pleonite 1 tapering laterally. The two species, however, differ from each other in the following characters (those of B. typhlops in parentheses): pleotelson having double carina dorsally (single carina) (see Fig. 14 A, B) and merus and carpus of male pereopod 2 longer than ischium (shorter than ischium).
Etymology. Named after for the double carina on the pleotelson.
description: Published as part of Shimomura, Michitaka, 2008, Bathycopea (Isopoda: Sphaeromatidea: Ancinidae) from Japan, with descriptions of two new species and redescription of B. parallela Birstein, pp. 25-49 in Zootaxa 1678 on pages 34-41, DOI: 10.5281/zenodo.180342