Heteroptychus claudeae, Baba, 2018

Baba, Keiji, 2018, Chirostylidae of the Western and Central Pacific: Uroptychus and a new genus (Crustacea: Decapoda: Anomura), Tropical Deep-Sea Benthos (Mémoires du Muséum national d'Histoire naturelle 212), pp. 1-612 : 580-586

Heteroptychus claudeae n. sp.

Figures 292-294

Uroptychus scambus — Baba 1981: 120; 1988: 43. — Baba et al. 2009: 59 (part), figs 49-51.

TYPE MATERIAL — Holotype: Wallis and Futuna Islands. MUSORSTOM 7 Stn CP564, 11°46’S, 178°27’W, 1015-1020 m, with Chrysogorgiidae gen. sp. ( Calcaxonia ), 20.V.1992, ♂ 5.0 mm ( MNHN-IU-2013-8571 ) . Paratypes: New Caledonia, Chesterfield Islands. MUSORSTOM 5 Stn CP387, 20°53.41’S, 160°52.14’E, 650-660 m, with Chrysogorgiidae gen. sp. ( Calcaxonia ), 22.X.1986, 1 ov. ♀ 4.5 mm (MNHN-IU-2013-8573) . Solomon Islands. SALOMON 2 Stn CP2189, 8°19.6’S, 160°01.9’E, 660-854 m, 23.X.2004, 1 ov. ♀ 3.9 mm (MNHN-IU-2014-17105) ; 2 ♂ 3.8, 4.0 mm, 2 ov. ♀ 3.9, 4.1 mm, 1 ♀ 3.7 mm (MNHN-IU-2014-17106) . – Stn DW2190, 08°24’S, 159°27’E, 140-263 m, 24.X.2004, 1 ♀ 4.0 mm ( MNHN- IU-2014-17107) . – Stn CP2250, 7°29.2’S, 156°16.7’E, 845-970 m, 2.XI.2004, 1 ov. ♀ 4.5 mm (MNHN-IU-2014-17108) . – Stn CP2253, 7°26.5’S, 156°15.0’E, 1200-1218 m, 2.XI.2004, 1 ov. ♀ 4.9 mm (MNHN-IU-2014-17109) . Wallis and Futuna Islands. MUSORSTOM 7 Stn CP564, collected with holotype, 7 ♂ 4.2-5.5 mm, 8 ov. ♀ 4.2-5.6 mm ( MNHN- IU-2014-17110) . – Stn CP567, 11°47’S, 178°27’W, 1010-1020 m, 20.V.1992, 4 ♂ 4.6-4.9 mm, 6 ov. ♀ 4.2-5.5 mm ( MNHN- IU-2013-12286, MNHN-IU-2013-12284, MNHN-IU-2013-11272) , 1 ♂ 5.8 mm, (MNHN-IU-2013-12285) . – Stn DW589, 12°16’S, 174°41’W, 400 m, 23.V.1992, 1 ov. ♀ 4.1 mm (MNHN-IU-2014-17111) . – Stn CP551, 12°15’S, 177°28’W, 791-795 m, 18.V.1992, 2 ♂ 4.2, 4.3 mm, 1 ov. ♀ 4.3 mm (MNHN-IU-2013-8572) . – Stn CP550, 12°15’S, 177°28’W, 800- 810 m, 18.V.1992, 1 ♂ 4.1 mm, 1 ov. ♀ 4.5 mm (MNHN-IU-2014-17112) . New Caledonia, Loyalty Ridge. BIOGEOCAL Stn CP297, 20°37’S, 167°11’E, 1230-1240 m, 28.IV.1987, 1 ♂ 3.8 mm (MNHN-IU-2014-17113) . MUSORSTOM 6 Stn CP438, 20°23’S, 166°20’E, 800 m, 18.II.1989, 1 ♂ 4.4 mm, 1 ov. ♀ 3.6 mm (MNHN-IU-2014-17114) . New Caledonia. HALIPRO 2 Stn BT96, 23°59’S, 161°55’E, 1034-1056 m, 25.XI.1996, 1 ♂ 4.2 mm (MNHN-IU-2014-17115) . – Stn BT101, 24°19’S, 161°43’E, 970-1063 m, 26.XI.1996, 1 ♂ 4.8 mm (MNHN-IU-2014-17116) . New Caledonia, Norfolk Ridge. BIO- CAL Stn CP31, 23°08’S, 166°51’E, 850 m, 29.VIII.1985, 1 ♂ 3.5 mm (MNHN-IU-2014-17117) . – Stn CP32, 23°07’S, 166°51’E, 825 m, 29.VIII.1985, 1 ov. ♀ 3.7 mm (MNHN-IU-2014-17118) . – Stn CP54, 23°10’S, 167°43’E, 950-1000 m, 1.IX.1985, 1 ♂ 4.5 mm, 2 ov. ♀ 4.7, 4.8 mm, 1 ♀ 3.8 mm (MNHN-IU-2014-17119) . – Stn CP61, 24°11’S, 167°32’E, 1070 m, 2.IX.1985, 1 ♂ 3.4 mm, 3 ov. ♀ 3.7-4.2 mm, 1 sp., sex indet., 2.4 mm (MNHN-IU-2013-12287, MNHN-IU-2013-12288, MNHN-IU-2013-11271) . BATHUS 3 Stn CP823, 23°23’S, 167°52’E, 980-1000 m, 29.XI.1993, 1 ♂ 5.0 mm ( MNHN- IU-2014-17120) . Vanuatu. MUSORSTOM 8 Stn CP992, 18°52.34’S, 168°55.16’E, 775- 748 m, 24.IX.1994, 1 ov. ♀ 4.7 mm (MNHN-IU-2014-17121) . – Stn CP1125, 15°57.63’S, 166°38.43’E, 1160-1220 m, 10.X.1994, 1 ov. ♀ 4.4 mm ( MNHN- IU-2014-17122) . – Stn CP1036, 18°01.00’S, 168°48.20’E, 920-950 m, 29.IX.1994, 1 ♂ 4.6 mm (MNHN-IU-2014-17123) . Tonga. BORDAU 2 Stn CP1613, 23°03’S, 175°47’W, 331-352 m, 17.VI.2000, 1 ♂ 4.1 mm (MNHN-IU-2014-17124) . – Stn CP1625, 23°28’S, 176°22’W, 824 m, 19.VI.2000, 1 ♀ 4.1 mm (MNHN-IU-2014-17125) .

ETYMOLOGY„ Named for Claude Crosnier for her hospitality during my stays in Paris.

DISTRIBUTION„ Japan, Taiwan, Indonesia, in 1175-1184 m, and now Wallis and Futuna Islands, Chesterfield Islands, Solomon Islands, New Caledonia, Vanuatu, Loyalty Ridge, Norfolk Ridge, and Tonga, in 331-1240 m.

SIZE„ Males, 3.4-5.5 mm; females, 3.7-5.6 mm; ovigerous females from 3.7 mm.

DESCRIPTION„ Carapace: Broader than long (0.7 × as long as broad), greatest breadth 2.1-2.3 × distance between anterolateral spines. Dorsal surface polished, moderately convex in profile on anterior half, feebly so on posterior half, ridged along posterior half of lateral margin. Lateral margins strongly convex around posterior third; anterolateral spine prominent, horizontally inclined anteromesially, occasionally directed straight forward, not reaching apex of rostrum. Rostrum distally narrow triangular, laterally concave, with interior angle of 20-30°, nearly horizontal or directed somewhat or moderately dorsally, reaching or slightly overreaching tip of eye; length 0.9 × breadth, 0.3 × length of remaining carapace; dorsal surface flattish but feebly concave basally. Lateral limit of orbit unarmed, acuminate or with small spine. Pterygostomian flap anteriorly produced to sharp strong spine; anterior surface well inflated, smooth or with feeble or distinct ridge in lateral midline on anterior portion; posterior height 0.1 × anterior height.

Sternum: Excavated sternum with roundly produced anterior margin, surface bearing sharp ridge in midline on anterior half. Sternal plastron in males 0.5-0.6 × as long as broad; in females, left and right parts of sternites 5-7 discontinuous, interrupted by loss of median parts. Sternite 3 having anterior margin broadly and deeply excavated, with small (rarely obsolescent) median notch, with or without small submedian processes. Sternite 4 with rounded anterolateral margin. Sternites 5 and 7 subequal in breadth, sternite 6 broadest.

Abdomen: Smooth and polished. Dorsal surface of somite 1 gently convex from anterior to posterior. Somite 2 tergite 2.4- 2.8 × (males), 2.1-2.6 × (females) broader than long; pleural lateral margin slightly concave, strongly divergent posteriorly, ending in blunt tip. Pleura of somites 3-4 somewhat more narrowed in females than in males, ending in rounded margin. Telson 0.4 × as long as broad; posterior plate feebly concave on posterior margin, length 1.4-1.8 × that of anterior plate.

Eyes: 1.3-1.4 × as long as broad, subovate. Cornea 0.5-0.7 × length of remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle 2.7-2.8 × longer than high. Article 2 of antennal peduncle fused with antennal scale. Antennal scale narrow triangular, reaching or barely reaching midlength of article 4, laterally with or without small spine. Distal 2 articles unarmed; article 5 1.2-1.3 × as long as article 4, breadth less than half height of ultimate antennular article. Flagellum of 9-11 segments.

Mxp: Mxp1 with bases broadly separated. Mxp3 basis unarmed on mesial ridge. Ischium relatively short,‰.4 × as long as merus, crista dentata without distinct denticles, flexor margin not rounded distally. Merus relatively thick mesiolaterally, with rounded ridge along flexor margin, unarmed. No spine on carpus.

P1: Smooth and nearly glabrous except for fingers, length 6.3-8.7 × (males), 6.3-6.9 × (females) that of carapace. Ischium with basally broad, blunt distodorsal process (elongate in large specimens) and lobe-like proximal process overhanging basis, unarmed elsewhere. Merus mesially with 1 well-developed distodorsal and 1 small or obsolescent distoventral spine, length 1.6-1.9 × (males), 1.6-1.8 × (females) that of carapace. Carpus 1.4-1.5 × longer than merus, with 2 terminal spines dorsomesially and several obsolescent spines ventromesially. Palm 5.1-5.4 × (males), 3.8-5.9 × (females) longer than broad, 0.8-0.9 × length of carpus, subequally broad medially and distally, proximally narrowed; mesial margin variably ridged from roundly to sharply, more sharply in large specimens, usually with no spine or serration (with obsolescent blunt spines in large specimens). Fingers directed somewhat anterolaterally, gaping in proximal half, straightly fitting to each other in distal half when closed, relatively slender, distally spooned; movable finger‰.5-0.6 × length of palm, opposable margin with prominent blunt process at midlength of gaping portion, distal to position of opposite truncate process on fixed finger.

P2-4: Setose along prehensile margins of propodi and dactyli. Meri subequal on P2 and P3, P4 merus 0.3-0.4 × length of P3 merus; length-breadth ratio, 5.1-5.8 on P2, 5.1-5.5 on P3, 2.5-2.8 on P4; P2 merus 0.9 × (1.1 × in largest male MNHN- IU-2013-12285) length of carapace, 1.1-1.2 × length of P2 propodus, P3 merus 1.1-1.3 × length of P3 propodus, P4 merus 0.6-0.7 × length of P4 propodus. Carpi subequal in length on P2 and P3, P4 carpus 0.3 × length of P3 carpus; carpusdactylus length ratio, 1.1-1.2 on P2 and P3, 0.4 on P4. Propodi subequal on P2 and P3, P4 propodus 0.8 × length of P3 propodus; propodus-dactylus length ratio, 1.4 on P2, 1.3-1.4 on P3, 1.2 on P4; flexor margin concavely curving in lateral view, unarmed. Dactyli subequal on P2 and P3, slightly shorter on P4; dactylus-carpus length ratio, 0.9 on P2 and P3, 2.2- 2.6 on P4; flexor margin with row of 13-16 sharp slender spines proximally diminishing and perpendicular to margin, ultimate somewhat larger than penultimate.

Eggs. Number of eggs carried, 20; size, 1.33 × 1.04 mm - 1.33 × 1.08 mm (MNHN-IU-2013-8573); 25 eggs; size, 1.23 × 1.49 mm - 1.41 × 1.67 mm (MNHN-IU-2013-12285).

Color. Two specimens in different color of Uroptychus scambus from Taiwan (now referred to H. claudeae ; see below) were illustrated by Baba et al. (2009: Figures 49 , 50 ).

REMARKS„ The antennal scale is fused with article 2 in H. claudeae , H. lemaitrei n. sp. and the western Atlantic H. brevis ( Benedict, 1902) , whereas in all the other species it is articulated. Heteroptychus brevis has both the rostrum and the anterolateral spines distally blunt and the P1 ischium bearing an obsolescent posterior dorsal lobe (see Figure 295 ), the features differentiating it from H. claudeae and H. lemaitrei . Heteroptychus claudeae differs from H. lemaitrei in having the carapace lateral margin smooth instead of bearing a small but distinct protuberance at the anterior end of branchial margin (see below under the remarks of H. lemaitrei ).

Unlike all the other species, the presence or absence of lateral orbital spine and the shape of the anterior margin of sternite 3 are unstable in H. claudeae ( Figure 294 ).

The specimens reported under U. scambus in my earlier paper ( Baba, 1981) from Japan are referable to H. claudeae , as also are the specimens from Taiwan ( Baba et al. 2009) except for the male from TAIWAN Stn CD141 (= H. scambus ; see below) and the specimens from Station PCP342 (not examined).

One of the specimens, the largest of the type series (1 ♂ 5.8 mm, MNHN-IU-2013-12285) collected together with the holotype from Wallis and Futuna, resembles H. lemaitrei in having a spiniform rostrum and in having the P1 ischium with a spiniform distodorsal spine. Unfortunately, the molecular analyses of this lot were unsuccessful (L. Corbari, personal comm.). Also, one of the Japanese specimens collected at Soyo-Maru Stn B4, 1700 m ( Baba, 1981) has a spiniform rostrum but the distodorsal process of the P1 ischium is distally obtuse, not spiniform. These two specimens are provisionally placed in U. claudeae .

The variability noted above, as well as the color difference in Taiwan specimens ( Baba et al. 2009: figs 49, 50) suggest that the species may likely contain cryptic species, for which further study is required.

Figures

FIGURE 49 Uroptychus brucei Baba, 1986a, male 13.7 mm (MNHN-IU-2014-16353). A, carapace and anterior part of abdomen, proximal part of right P1 included,dorsal.B, same,lateral.C, sternal plastron,with excavated sternum and basal parts of Mxp1.D, left antenna,ventral.E, right Mxp3,ventral.F, right P1, proximal part,ventral.G, same,dorsal.H, right P2,lateral. I, same,distal part,setae omitted. Scale bars:A, B, F,G, H, 5 mm; C-E,I, 1 mm.

FIGURE 50 Uroptychus buantennatus n. sp.,A-C, E-G, holotype,ovigerous female 3.0 mm (MNHN-IU-2014-16354);D, paratype,male 2.5 mm (MNHN-IU-2014-16356);E, paratype,male 2.5 mm (MNHN-IU-2014-16355).A, carapace and anterior part of abdomen,proximal part of right P1 included, dorsal.B, same,lateral. C, anterior part of sternal plastron. D, sternal plastron,with excavated sternum and basal parts of Mxp1; E, telson.F, left antenna,ventral. G, left Mxp3,ventral. H, same,lateral. Scale bars:1 mm.

FIGURE 292 Heteroptychus claudeae n. sp., A-C, E-H, holotype, male 5.0 mm (MNHN-IU-2013-8571); D, paratype, ovigerous female 4.5 mm (MNHN-IU-2014-17110). A, carapace and anterior part of abdomen, dorsal. B, same, lateral. C, sternal plastron, with excavated sternum and basal partsof Mxp1.D, same.E,telson.F, left antenna,ventral.G, right Mxp3,ventral.H, same,lateral.Scale bars:1 mm.

FIGURE 293 Heteroptychusclaudeae n. sp.,holotype,male 5.0 mm (MNHN-IU-2013-8571).A, right P1,dorsal.B, same,proximal part omitted, mesial.C, same, fingers, ventral. D, left P2, lateral. E, same, distal part, setae omitted, lateral. F, left P3, lateral. G, left P4, lateral.Scale bars: 1 mm.

FIGURE 294 Heteroptychus claudeae n.sp.,paratypes,showinganterior part of carapace and anteriorpart of sternal plastron (MNHN-IU-2014-17110). A, male 4.4 mm. B, male 4.6 mm.C, male 5.7 mm. D, ovigerous female 5.1 mm. E, ovigerous female 5.2 mm.F, ovigerous female 5.6 mm. Scale bar:1 mm.

FIGURE 295 Heteroptychus brevis (Benedict,1902),holotype of Uroptychus brevis, ovigerous female 5.2 mm, USNM 20566.A, anterior part of carapace,dorsal. B, sternal plastron,with excavated sternum and basal parts of Mxp1.C, left antenna, ventral. D, right P1, proximal part, lateral. E, same, dorsal.F, right P2,lateral.G, right P3, lateral.H, right P4,lateral.Scales:1 mm.