Bathycopea oculata, 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 : 27-34

publication ID	https://doi.org/ 10.5281/zenodo.180342
DOI	https://doi.org/10.5281/zenodo.6236164
persistent identifier	https://treatment.plazi.org/id/E74BC475-A754-EE66-FF67-BEB7FAD485E0
treatment provided by	Plazi
scientific name	Bathycopea oculata
status	sp. nov.

Treatment

Bathycopea oculata View in CoL sp. nov.

Figs 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7

Material examined. Holotype. Male, 2.6 mm ( KMNH IvR 700,033), dissected and mounted on glass slides, St.4-2, off Cape Toi, Miyazaki Prefecture, 31º26.20’N, 131º39.84’E- 31º25.65’N, 131º39.62’E, 528– 523 m, sand, 3 m ORE beam trawl, TRV Toyoshio-maru, 18 May, 2004, collected by MS.

Paratypes. Ovigerous female, 4.5 mm ( KMNH IvR 700,030), dissected and mounted on glass slides, ovigerous female, 4.5 mm ( KMNH IvR 700,031), dissected and mounted on aluminum stubs for SEM observation, ovigerous female with 17 juveniles, 4.5 mm ( KMNH IvR 700,032), dissected and mounted on glass slides, TRV Toyoshio-maru, St. 9, off Mi-shima Island, Yamaguchi Prefecture, Sea of Japan, 34º47.40’N, 131º19.80’E, 99 m, sand and mud, sledge net, 18 November, 1999, collected by MS; 3 non-ovig. females, 1.7 mm ( KMNH IvR 700,252), 1.4 mm ( KMNH IvR 700,253), 1.2 mm ( KMNH IvR 700,254), whole specimens in glass bottle, St. X(5’), off Amami-oshima, Kagoshima Prefecture, 28º22.37’N, 129º15.97’E- 28º22.28’N, 129º15.43’E, 290 m, sand, 3 m ORE beam trawl, 21 May, 2004, collected by Dr. S. Ohtsuka.

Diagnosis. Body dorsally smooth. Pereonites 1 to 7 increasing in width posteriorly, without dorsal keels. Pereonite 2 broadly projected anterior-laterally. Pleonite 1 strongly arched dorsally; lateral margins broadly rounded. Pleotelson gradually decreasing in width posteriorly, with single dorsal carina. Eye lobes well-developed, with 43–57 ommatidia. Uropod moderately broad, about 4–4.7 times as long as width, with short tooth medial-laterally, without large serrations on lateral margin. Epistome triangular in shape, apically rounded, not surpassing frontal margin of antennule peduncular article 1; margins straight. Pereopod 1: distal corner of carpus blunt, broadly rounded. Pereopod 2 in male: merus and carpus shorter than ischium; propodus about 2.9 times as long as carpus, slightly curved inward, without proximal projections, with 3 sensory robust setae ventral-proximally and simple seta ventral-distally, ventral-distally denticulated; dactylus as long as propodus, curved inward, with few short simple setae.

Description of the holotype male. Body ( Fig. 2 View FIGURE 2 A, B) about 1.6 times as long as maximum width. Head ( Fig. 2 View FIGURE 2 A) partly fused with pereonite 1. Pleon ( Fig. 2 View FIGURE 2 A, B) slightly broader than pereonite 7. Pleotelson ( Fig. 2 View FIGURE 2 A) about 1.2 times as broad as long, apically rounded; central part distinguished by ridge smooth and flattened dorsally. Uropod ( Fig. 2 View FIGURE 2 A) marginally crenulated, with many short setae laterally.

Antennule ( Fig. 2 View FIGURE 2 A, D) peduncular article 1 about as long as broad, dorsally with 4 short setae and 11 simple scales, cuticularized on medial margin; article 2 with 5 short setae and few simple scales, strongly ridged distal-dorsally, cuticularized on medial margin; article 3 longest, with few short medial, lateral and dorsal setae. Flagellum of 8 articles, shorter than peduncle: article 1 minute; article 2 shorter than peduncular article 2; article 3 half as long as article 2, with medial seta; articles 4 to 8 decreasing in length gradually, each articles with some simple setae and aesthetascs distally.

Antenna ( Fig. 2 View FIGURE 2 C, E) article 1 with fine setae laterally; article 2 broadest at nearly proximal base, with several setae medially and simple seta laterally and distally; article 3 longest and widest, with 10 setae medially and 1 setae and many fine setae laterally; article 4 as long as article 2, with 9 setae medially and 2 simple setae laterally. Flagellum about as long as peduncle: articles 1–3 with some simple scales; article 1 slightly longer than peduncular article 4, with many setae medially and few setae laterally; article 2 about 0.3 times as long as article 1, with 5 setae medially; article 3 as long as article 2, with 6 medial setae; articles 4 to 10 decreasing in length, each with some simple setae.

Left mandible ( Fig. 2 View FIGURE 2 F) article 1 of palp robust, with some setulated scales, with simple seta ventrally; article 2 about 1.5 times as long as article 1, with 5 pectinate setae, and some setulated scales; article 3 shortest, with 8 pectinate setae. Incisor slender, widest at middle part. Right mandible ( Fig. 2 View FIGURE 2 G): article 1 of palp robust, with some setulated and simple scales; article 2 with 4 pectinate setae, some simple and setulated scales; article 3 about 0.3 times as long as article 2, with 7 pectinate setae.

Maxillule ( Fig. 2 View FIGURE 2 H) with mesial lobe bearing 1 apical long and few fine setae; lateral lobe with 6 apical stout serrate and 2 simple setae, and few setulated scales.

Maxilla ( Fig. 2 View FIGURE 2 I) with mesial lobe bearing 2 apical simple spines and 3 setulated scales; middle lobe with 4 apical pectinate setae; lateral lobe with 4 apical simple setae.

Maxilliped ( Fig. 3 View FIGURE 3 A) article 1 with ventral seta and few simple scales; article 2 trapezoidal, about 3 times as long as article 1, with 1 medial seta, and setulated scale and many simple scales; article 3 as long as article 2, with 2 long distal-medial setae and 4 setulated and 4 simple scales; article 4 narrow, slightly shorter than article 3, with 3 distal-medial and 2 lateral setae, and 6 setulated scales; article 5 minute, with 4 apical long and few lateral short setae; endite trapezoidal, bearing many fine marginal setae, with many setulated and simple scales ventrally, and coupling hook medially.

Pereopod 1 ( Fig. 2 View FIGURE 2 J) basis robust, dorsally with 8 short setae; ischium about 0.7 times as long as basis, without setae; merus trapezoidal, about half as long as ischium, without setae; carpus as long as merus, distally rounded, distally with many short setae; propodus with row of triangular robust setae on palm, proximalmedially with some setulated and simple scales; dactylus stylet-like, with 2 blunt teeth proximal-ventrally, reaching to carpus, without setae.

Pereopod 2 ( Fig. 2 View FIGURE 2 K) basis with short simple seta and many simple scales; ischium about 0.3 times as long as basis, with few simple scales; merus subtriangulate, shorter than ischium, with simple seta ventral-distally; carpus trapezoidal, about as long as merus, with 2 simple setae medially, ventral-distally denticulated; propodus robust, slightly curved inward, with 3 robust sensory setae ventral-proximally and simple seta ventral-distally, ventral-distally denticulated; dactylus slender, about as long as propodus, curved inward, with 2 ventral and 2 apical short simple setae.

Pereopod 7 ( Fig. 3 View FIGURE 3 C) basis with 12 short ventral and 4 dorsal setae; ischium about 0.3 times as long as basis, without setae; merus about twice as long as ischium, with 1 long and 6 short setae ventrally, 2 simple setae dorsal-distally and simple seta medial-distally and lateral-distally; carpus longer than merus, distal-ventrally with 2 long setae and broom seta, and with 2 setae dorsal-distally; propodus about 0.9 times as long as carpus, with 3 long distal-ventral, 1 long ventral and 2 long distal-dorsal setae; dactylus narrowest article; distally with 3 short simple seta and unguis

Pleopod 1 ( Fig. 3 View FIGURE 3 D) with some simple scales ventrally: peduncle about 2.8 times as broad as long, with 3 coupling hooks distal-medially and few fine setae medially, and many short setae laterally; endopod about 2.1 times as long as peduncle, slightly broader than long, bearing many long plumose marginal setae and fine simple setae; exopod narrower than endopod, longer than endopod, with many long plumose setae and many fine setae marginally and few simple short setae ventrally.

Pleopod 2 ( Fig. 3 View FIGURE 3 E) with some simple scales ventrally: peduncle about 2.1 times as broad as long, with 3 coupling hooks distal-medially and many fine setae marginally; endopod moderately narrow, triangulate, about 2.3 times as long as broad, 3.6 times as long as peduncle, bearing some long plumose and fine simple setae; appendix masculina as long as endopod, with fine microtrichs ventrally; exopod ovate, about 0.6 times as long and about 0.7 times as wide as endopod, with many long plumose and many fine setae marginally.

Pleopod 3 ( Fig. 4 View FIGURE 4 A) with some simple scales ventrally: peduncle longer than those of pleopods 1 and 2, about 2.1 times as broad as long, with 2 coupling hooks distal-medially and many fine short setae marginally; endopod broad, about 2.3 times as long as peduncle, longer than broad, bearing 4 short plumose setae apically; exopod articulated, bearing many plumose marginal setae.

Pleopod 4 ( Fig. 4 View FIGURE 4 B): endopod longer than exopod, tapering to apex, with simple seta apically; exopod pyriform in shape, about twice as long as broad, bearing simple seta laterally.

Pleopod 5 ( Fig. 4 View FIGURE 4 C): endopod about 2.3 times as long as broad, with 2 notches proximal-medially and many fine setae distal-medially; exopod as long as endopod, with simple seta medially and many fine setae distal-medially.

Description of the paratype female. Pereopod 2 ( Fig. 3 View FIGURE 3 B): basis with 6 short ventral and 1 dorsal-distal setae; ischium about 0.3 times as long as basis, without setae; merus as long as ischium, with 1 long and many fine setae ventrally and 2 short setae dorsally; carpus longer than merus, with 2 long ventral-distal and many fine ventral setae; propodus as long as carpus, with 2 long ventral and 3 dorsal-distal setae; dactylus narrowest article; with 2 distal setae and curved unguis.

Pleopod 2 ( Fig. 3 View FIGURE 3 F) with many simple scales ventrally: peduncle about 2.1 times as broad as long, with 3 coupling hooks distal-medially and many fine setae marginally; endopod broad, about 3 times as long as peduncle, longer than broad, bearing many long plumose marginal setae and fine simple setae; exopod ovate, about 0.8 times as long as endopod, with many long plumose and many fine setae marginally.

Additional notes on paratype. One paratype female was observed with SEM ( Figs. 5–7 View FIGURE 5 View FIGURE 6 View FIGURE 7 ).

Body ( Fig. 5 View FIGURE 5 A–C) moderately smooth: setation scattered. Cephalon ( Fig. 5 View FIGURE 5 A) completely fused with pereonite 1 at middle part. Dorsal setae ( Fig. 5 View FIGURE 5 E) on pereon branched, arising from sheath. Marginal setae on uropods ( Fig. 5 View FIGURE 5 D) penicillate. Dorsal-distal part of antennule peduncular article 2 ( Fig. 4 View FIGURE 4 F) strongly ridged. Incisors of right mandible ( Fig. 6 View FIGURE 6 A) with many scales having row of short setae; lacinia mobilis with 2 cusps, branched at its base; molar process setulated distally. Incisor with left mandible ( Fig. 6 View FIGURE 6 B) with many scales, with setulate robust seta and molar process. Mandibular palp ( Fig. 6 View FIGURE 6 C): article 2 with 23 curved simple scales, marginally setulated; article 3 triangulate, distally pointed, without scales. Maxilliped palp ( Fig. 6 View FIGURE 6 D): scales on article 2 nearly straight, without setae; scales on articles 3 and 4 nearly straight, with long setae; article 5 without scales. Coupling hook of maxilliped ( Fig. 6 View FIGURE 6 E) curved ventrally; inner margin denticulate. Pereopod 1 ( Figs. 6 View FIGURE 6 F, 7A, B): palm of propodus with row of many short simple setae and triangulate setae; scales of propodus with many setae agglutinated on basis. Pereopod 7 ( Fig. 7 View FIGURE 7 C, D): distal setae on carpus feather-like, broad apically; scales simple without setae. Pleopod 1 ( Fig. 7 View FIGURE 7 E, F): plumose setae consisting of robust trunk and many thin, membranous setae; scales rudimentary, without setae.

Colour. Colour in life ( Fig. 1 View FIGURE 1 ) yellowish white, with dark brown chromatophores. Eyes: pigment colour brownish red.

Remarks. Both Bathycopea oculata sp. nov. and Bathycopea daltonae from the shallow-water habitats in California have eyes. B. oculata is, however, distinguished from B. daltonae by the following features (those of B. daltonae in parentheses): uropod about 4–4.7 times as long as width, with short tooth medial-laterally (5.4 times as long as width, without short tooth medial-laterally) and pleotelson gradually decreasing in width posteriorly (more sharply decreasing).

Etymology. From the Latin oculus, referring to the well-developed eyes with many ommatidia.