Bathycopea dicarina, Shimomura, Michitaka, 2008

Shimomura, Michitaka, 2008, Bathycopea (Isopoda: Sphaeromatidea: Ancinidae) from Japan, with descriptions of two new species and redescription of B. parallela Birstein, Zootaxa 1678, pp. 25-49 : 34-41

publication ID	https://doi.org/ 10.5281/zenodo.180342
DOI	https://doi.org/10.5281/zenodo.6236166
persistent identifier	https://treatment.plazi.org/id/E74BC475-A75F-EE7F-FF67-BB67FC4E8288
treatment provided by	Plazi
scientific name	Bathycopea dicarina
status	sp. nov.

Treatment

Bathycopea dicarina View in CoL sp. nov.

Figs 8–13 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 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 View FIGURE 8 A, B) about 1.5 times as long as maximum width. Head ( Fig. 8 View FIGURE 8 A) fused with pereonite 1 at middle. Pleon ( Fig. 8 View FIGURE 8 A) slightly broader than pereonite 7; dorsum nearly flattened. Pleotelson ( Fig. 8 View FIGURE 8 A, B) about 1.6 times as broad as long, apically rounded; dorsum arched. Uropodal sympod with protuberance dorsal-proximally; endopod ( Fig. 8 View FIGURE 8 A) marginally crenulated, with many short setae laterally and short tooth distal-medially.

Antennule ( Fig. 8 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 8 H) with inner lobe bearing 1 apical long seta; outer lobe with 6 apical robust setae and few setulated scales.

Maxilla ( Fig. 8 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 ).

Body ( Fig. 10 View FIGURE 10 A–D) setation scattered. Dorsal seta ( Fig. 10 View FIGURE 10 F) on pereonite 5 branched, arising from shallow pit; dorsal seta ( Fig. 11 View FIGURE 11 A) on pleon strongly curved inward, with broad membranaceous fringe. Marginal setae on uropods ( Fig. 10 View FIGURE 10 E) penicillate. Antennule peduncular articles 1 ( Fig. 11 View FIGURE 11 B) ridged distal-dorsally. Setae on medial margin of antenna ( Fig. 11 View FIGURE 11 C) with many fine setae on half of its base. Incisors of mandibles ( Fig. 11 View FIGURE 11 D, E) with many setulated scales. Mandibular palp ( Fig. 11 View FIGURE 11 F): article 2 with many simple scales, marginally setulated; article 3 distally truncate, without scales. Maxilliped palp ( Fig. 12 View FIGURE 12 A): articles 2–4 with many scales bearing long fine setae; article 5 without scales. Pereopod 1 ( Fig. 12 View FIGURE 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 View FIGURE 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 View FIGURE 12 E): scales on merus and propodus simple medially, setulated on marginal ridge. Pleopod 1 ( Fig. 13 View FIGURE 13 A): scales rudimentary, simple. Pleopod 5 ( Fig. 13 View FIGURE 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 View FIGURE 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.