Pseudopinnixa carinata Ortmann, 1894

Komai, Tomoyuki & Konishi, Kooichi, 2012, Reappraisal of the Systematic Position of the Supposed Pinnotherid Crab Pseudopinnixa carinata (Crustacea: Decapoda: Brachyura), Species Diversity 17 (1), pp. 29-37 : 30-36

Pseudopinnixa carinata Ortmann, 1894 (Figs 1–5)

Pseudopinnixa carinata Ortmann, 1894: 694 , pl. 23, g. 6; Tesch 1918: 287 (list); Sakai 1939: 600; 1955: 110; 1976: 586 (English text), pl. 203, g. 1; Schmitt et al. 1973: 126 (bibliography); Miyake 1983: 243 (list); Muraoka 1998: 49; Komai 1999: 90; MarumuraandKosaka 2003: 68; NgMihoBay, TottoriPrefecture, 35°28.710'N, 133°18.414'E, et al. 2008: 248 (list), 252 (mention); Palacios-ffieil et al. 9.3 m, sand bottom, 18 August 2003, SM grab, CBM-ZC 2009: 461. 8144; 2 males (4.6×6.0 mm, largeronebadlydamaged), 3 youngfemales (3.8×5.2 to 5.5× 7.3 mm), similarlocality, Materialexamined. Syntypes: 9 males (11.0×13.6 to 35°28.903'N, 133°18.576'E, 12 m, 18 August 2003, SMgrab, 13.2×17.0 mm), 17 females (9.7×12.5 to 12.3×16.0 mm), CBM-ZC 8145; 2 males (3.7×5.0, 7.9× 10.6 mm), 2 young TokyoBay, 1880–1881, coll. L. Döderlein, MZS 1167 (spir-females (4.3×5.7, 5.4× 7.3 mm), 4 juveniles (2.2×2.7 to it); 1 male (10.0×13.0 mm), samedata, MZS 308 (dry); 3 2.6×3.0 mm), similarlocality, 35°29.089'N, 133°18.591'E, males (11.0×14.5 to 11.5× 15.6 mm), 2 females (12.1×16.6, 12.7 m, sand, 30 January 2004, SMgrab, CBM-ZC 8154; 1 13.3× 17.4 mm), samedata, MZS 309 (dry). female (4.5× 6.4 mm), similarlocality, 5 m, 30 January 2004, Non-type: 1 male (3.6× 4.8 mm), RV Tansei-maru, KT95- SMgrab, CBM-ZC 10199.

5 cruise, stn TB-10, SE of Cape Taito, Misaki, Boso Peninsu- Redescription . A dult male. Carapace (Figs 1A, B, 2A) la, 54–55 m, 21 April 1995, dredge, coll . T. Komai, CBM-ZC 1.3–1. 4 times wider than long, greatest width somewhat 9303; 1 male (5.0× 7.2 mm), Kiso-sansen River estuary, Ise posterior to midlength; dorsal surface slightly convex trans- Bay , Mie Prefecture, intertidal sand at, 30 April 2002, coll . versely, somewhat more convex longitudinally, granulate H. Sekiguchi, CBM-ZC 9867; 1 male (5.1× 6.8 mm), 1 young adjacent to lateral margins, remaining part nearly smooth, female (4.6× 6.6 mm), 9 juveniles (2.6×3.0 to 2.9× 3.5 mm), withdistinctsubmarginalridgealongposteriormargin (Fig. 5A); regions not demarcated. Inter-orbital (Fig. 2B) area granulate; frontal margin granulate, slightly de exed, slightly concave on either side of slightly produced, blunt midpoint; lateral frontal angle not produced. Anterolateral margin broadly arcuate, delimited by granulate ridge running from suborbital margin to branchial region; posterolateral margin not con uent with anterolateral margin. Epimera partially visible in dorsal view. Upper orbital margin granulate; lower orbital margin clearly separated from suborbital ridge, inner angle blunt, unarmed. Pterygostomial region (Fig. 2C) with slightly arcuate, granulate suborbital ridge extending from anterolateral angle of buccal frame; lower part with scattered short setae . Lateral margin of buccal frame with sharp, granulate carina. Epistome (Fig. 2B) relatively short, ventral margin slightly produced into blunt point medially, shallowly concave on either side of midpoint; surface shallowly concave.

Eye (Fig. 2B) small, completely lling orbit, movable. Antennular basal segments separate by narrow median septum; antennular peduncle folding transversely (Fig. 2B). Antennal peduncle (Fig. 2B) vertical, reaching lateral frontal angle by distal margin of third segment; agellum longer than width of front, consisting of 7–9 articles.

ffiird maxilliped (Fig. 2G, H) with numerous elongate setae on inner surface of carpus and inner surface and margins of dactylus. Merus with shallow depression lled with small granules distomesially on outer face; inner face shallowly depressed in medial half, with distinct longitudinal groove along mesial margin, distal margin produced into triangular lobe. Carpus sparsely granulate on outer surface. Articulation between propodus and dactylus strongly oblique. Propodus with few moderately long setae on inner face. Dactylus elongate oval, spatulate. Exopod covered by lateral margin of ischium-merus in mesial half, having strongly sinuous lateral margin; outer face with longitudinal row of granules delimiting shallowly depressed mesial half.

Chelipeds equal or subequal, similar (Figs 1B, 3A). Chela (Fig. 2A, B) relatively small, length 0.30–0.55 of carapace width; ngers crossing at tip when closed. Dactylus subequal in length to palm, slightly curving, terminating in subacutely pointed tip; outer face with row of short, sti setae adjacent to dorsal margin; dorsal surface rounded; cutting edge with a median tooth (in largest specimen, tooth prominent). Fixed nger nearly straight, unarmed along cutting edge. Palm approximately as long as high; dorsal margin keeled, gently arcuate in outer view; outer face with longitudinal row of setae dorsally, sharply carinate ventrally including xed nger, bearing row of setae; inner face with sparse setae; ventral margin sinuous in outer view. Carpus subequal in length to palm measured along dorsal margin, lacking prominent spine or tooth, surfaces nearly smooth; inner face with granules dorsally and ventrally. Merus (Fig. 2C, D) stout; dorsal margin convex, with row of long setae on distal half; outer (posterior) face sparsely granulate, outer ventral margin nearly straight; inner face with granules dorsally and ventrally, otherwise nearly smooth; distal margin granulate. Ischium very short.

Eye (Fig. 2B) small, completely lling orbit, movable. Antennular basal segments separate by narrow median septum; antennular peduncle folding transversely (Fig. 2B). Antennal peduncle (Fig. 2B) vertical, reaching lateral frontal angle by distal margin of third segment; agellum longer than width of front, consisting of 7–9 articles.

Ambulatory legs (Figs 1B, 4A–E) moderately short and stout. ffiird and fourth pereopods (second and third ambulatory legs) subequal in length, longer than second and

h pereopods (rst and fourth ambulatory legs), lengths 1.1–1.2 times carapace width; h pereopod with merus reaching midlength of merus of fourth pereopod. Ischia with outer face granulate (second to fourth pereopods) or smooth (h pereopod). Meri coarsely granulate on upper and lower margins; posterior faces with scattered short setae and some short, transverse rows of granules on upper part and scattered coarse granules on lower part; row of setae on upper and lower margin. Carpi smooth (second pereopod) or coarsely granulate (third to h pereopods) on extensor margin; posterior faces with irregular longitudinal rows of granules along midline; propodi subequal in length to (second to fourth pereopods) or shorter than (h pereopod) carpi, bearing granules (second to fourth) or nearly smooth (h). Dactyli longer than propodi measured along extensor margin, each gradually tapering to acute apex, somewhat attened lance-shaped (on second to fourth) or subconical (on h); extensor surface with 2 (on second and third) or 4 shallow longitudinal sulci, median part somewhat elevated; posterior and anterior margins bluntly carinate in second to fourth pereopods; exor surface with 2 shallow longitudinal sulci anking slightly elevated median part.

First to third thoracic sternites (Fig. 2D, E) clearly divided by distinct sutures. First and second sternites deeply depressed; rst sternite trilobed anteriorly with median tubercle and noticeably produced anterolateral angles. Second sternite having distinct carina bordering anterior margin, anterolateral angles produced anteriorly. ffiird and fourth sternites granulate, medially slightly concave. Fi h sternite with small, tubercular abdomen locking press button at anteromesial portion. Exposed part of eighth sternite subquadrate, nearly smooth on surface. Penis sternal, located at anterior end of eighth sternite. Sterno-abdominal cavity bordered by granulate ridge, more distinct on fourth sternite.

Gill formula summarized in Table 1; second maxilliped with small podobranchia; third maxilliped with small podobranchia and 2 greatly unequal, well developed arthrobranchiae (second gill much larger than rst gill); rst pereopod with 2 large arthrobranchiae; pleurobranchia above base of second pereopod smaller than arthrobranchiae on rst pereopod.

Abdomen (Fig. 5A) moderately narrow, with third to sixth somites functionally fused, although sutures dividing somites distinct. First and second somites short, smooth on outer faces. ffiird somite widest, with rounded proximolateral angles. Fourth somite with concave lateral margins. Tel- son subtriangular with blunt tip, nearly as long as wide.

First gonopod (Fig. 5B–D) moderately slender, laterally compressed with cross section subovate, reaching suture between third and fourth thoracic sternite, distally curving dorsally; ventral margin bordered by granules over entire length; chitinous terminal process somewhat attened, shallowly concave on mesial side, distally rounded, obscured by numerous sti setae. Second gonopod (Fig. 5E, F) small, moderately stout, sinuous, tapering distally.

Female. Generally similar to adult males, but chela (Fig. 3E) proportionally smaller, ventral margin almost straight, setae longer than in males, lacking tooth on cutting edge of dactylus. Abdomen (Fig. 5G) broad, subcircular, broadest at fourth and h somites; rst somite with distinct transverse ridge running across entire width; lateral margins of second to sixth somites minutely granulated, those of sixth somite strongly convex proximally; telson broadly subtriangular, 3.0 times broader than long, distolateral margins faintly concave.

Coloration in life.B ody and appendages generally gray; carapace with brown markings surrounding median part.

Distribution.K nown only from Japan: o Cape Inubo and o Misaki, Chiba Prefecture; Tokyo Bay; Osaka Bay; Miho Bay, Tottori Prefecture; Moji, Fukuoka Prefecture; intertidal to 55 m ( Ortmann 1894; Sakai 1976; Marumura and Kosaka 2003; Palacios-ffieil et al. 2009; this study).

Habitat.O ccurring on muddy sand bottoms and probably burrowing in sediments. ffiere is no evidence of association with other inverterbates.

Remarks.Or tmann (1894) listed 13 males and 19 females examined in his account of Pseudopinnixa carinata , although he did not designate a holotype. ffierefore, these 32 specimens are syntypes. During a stay in the Musée Zoologique, Strasbourg, in 1997 and 1998, the rst author located all these specimens, although they were separated into three di erently preserved lots. Nine males and 17 females (MZS 1167) were preserved in ethanol and are in good condition. ffiree males and two females (MZS 309) are now dried. One male specimen in dry condition was found in the box containing the syntypes of Pinnaxodes major Ortmann, 1894 (MZS 308), but it was probably just misplaced. ffiere is no doubt that these syntypic specimens all represent the same species. As the genus is monotypic and there are no known taxonomic or nomenclatural problems associated with this species, we do not see the need to select a lectotype for the time being.

ffie six subadult specimens (3.8×5.2 to 5.5× 7.3 mm; CBM-ZC 8144, 8145, 8154) are androgynous in having a triangular abdomen with functionally fused third to sixth somites, which is proportionally slightly wider than in normal males, gonopores on the sixth thoracic sternite, and biramous rst to fourth pleopods. ffie smallest normal female is 4.5× 6.4 mm (CBM-ZC 10199), i.e., within the size range of these aberrant specimens. Androgyny in the Brachyura is little known, although Ahyong and Ng (2008) demonstrat- ed examples of this sexual aberration in four species in two genera of Pinnotheridae .