Heteroptychus anouchkae Baba 2018, n. sp.
Creators: name: Baba, Keiji
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Chirostylidae
Heteroptychus
Heteroptychus anouchkae

description: Heteroptychus anouchkae n. sp.
Figures 287, 288, 306I
TYPE MATERIAL — Holotype: New Caledonia, Norfolk Ridge. BATHUS 3 Stn CC 841, 23°03’S, 166°53’E, 640-680 m, 30.XI.1993, ov. ♀ 4.7 mm (MNHN-IU-2014-17097). Paratypes: New Caledonia. HALIPRO 1 Stn CP854, 21°45.37’S, 166°38.34’E, 650-780 m, 19.III.1994, 1 ♂ 4.6 mm (MNHN-IU-2014-17098). – Stn CH 872, 23°03’S, 166°53’E, 620-700 m, 30.III.1994, 1 ♂ 4.6 mm, 3 ov. ♀ 4.0- 4.3 mm (MNHN-IU-2014-17099). – Stn CH 873, 23°01’S, 166°53’E, 640-680 m, 30.III.1994, 1 ov. ♀ 4.5 mm (MNHN-IU-2014-17100). New Caledonia, Norfolk Ridge. BATHUS 3 Stn CP831, 23°04’S, 166°56’E, 650-658 m, 30.XI.1993, 1 ♂ 4.7 mm (MNHN-IU-2014-17101), 1 ov. ♀ 4.5 mm (MNHN-IU-2013-12292). – Stn CC 841, collected with holotype, 2 ov. ♀ 4.3, 4.5 mm (MNHN-IU-2014-17102). – Stn CP846, 23°03’S, 166°58’E, 500- 514 m, 1.XII.1993, 1 ov. ♀ 3.4 mm (MNHN-IU-2014-17103). – Stn CC848, 23°02’S, 166°53’E, 680-700 m, 1.XII.1993, 1 ♂ 4.1 mm (MNHN-IU-2013-12291). New Caledonia, Loyalty Ridge. MUSORSTOM 6 Stn DW483, 21°19.80’S, 167°47.80’E, 600 m, 23.II.1989, 1 ov. ♀ 4.0 mm (MNHN-IU-2013-12294).
ETYMOLOGY„ Named for Anouchka Sato who helped me in various ways during my stays at the Paris Museum.
DISTRIBUTION„ Loyalty Ridge, New Caledonia and Norfolk Ridge, in 500- 780 m.
SIZES„ Males, 4.1-4.7 mm; females, 3.4-4.7 mm, ovigerous females from 3.4 mm.
DESCRIPTION„ Small species. Carapace: 0.6-0.7 × as long as broad, greatest breadth 2.1-2.4 × distance between anterolateral spines. Dorsal surface polished, moderately convex from anterior to posterior, ridged along posterior half of lateral margin; greatest breadth measured at posterior quarter. Lateral margins strongly convexly divergent posteriorly; anterolateral spine prominent, directed straight forward but somewhat dorsally, slightly overreaching rostral tip. Rostrum distally narrow triangular, with interior angle of 23-37°, distally sharply pointed, straight horizontal, reaching or slightly falling short of tip of eye; length 0.6-0.8 × breadth, 0.2-0.3 × length of remaining carapace; dorsal surface flattish but feebly concave basally. Lateral limit of orbit with small but distinct spine. Pterygostomian flap very low in posterior half (posterior height 0.1 × anterior height); anteriorly produced to sharp strong spine; anterior surface well inflated, with longitudinal ridge bearing 2 or 3 obsolescent (females and small males) or distinct, blunt (males) processes, occasionally smooth.
Sternum: Excavated sternum with subtriangular anterior margin, surface with 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 pair of small obtuse median processes. Sternite 4 with rounded anterolateral margin.
Abdomen: Smooth and polished. Dorsal surface of somite 1 gently convex from anterior to posterior. Somite 2 tergite 2.3-2.6 × (females), 3.0-3.4 × (males) broader than long; pleural lateral margin moderately concave, strongly divergent posteriorly, ending in blunt tip. Pleura of somites 3-4 strongly tapering in females, less so in males, ending in rounded margin. Telson 0.3-0.4 × as long as broad; posterior plate moderately concave on posterior margin, length subequal to or slightly more than that of anterior plate.
Eyes: About 1.8 × as long as broad, subovate, medially inflated, distally and proximally narrowed; cornea 0.4 × length of remaining eyestalk.
Antennule and antenna: Ultimate article of antennular peduncle 3.5 × longer than high. Article 2 of antennal peduncle without lateral spine. Antennal scale narrow triangular, ending in or barely reaching midlength of article 4, distinctly articulated. Distal 2 articles unarmed; article 5 1.1-1.3 × longer than article 4, breadth 0.44 × height of ultimate antennular article. Flagellum of 9-12 segments directed laterally or posteriorly.
Mxp: Mxp1 with bases broadly separated. Mxp3 basis with 3-4 denticles on mesial ridge. Ischium relatively short, 0.4 × as long as merus, crista dentata with 1-3 obsolescent denticles on proximal third of length, flexor margin not rounded distally. Merus relatively thick mesio-laterally, with rounded ridge along flexor margin, unarmed. No spine on carpus.
P1: Smooth and nearly glabrous except for fingers, 7.5-8.7 × (males), 6.8-7.1 × (females) longer than carapace. Ischium with basally broad, distally blunt distodorsal process and lobe-like proximal process overhanging basis. Merus with 2 distodorsal spines mesially, length 1.8-1.9 × (males), 1.4-1.7 × (females) that of carapace. Carpus 1.5-1.6 × (males), 1.3-1.4 × (females) longer than merus, dorsally with 3 or 4 terminal spines, ventromesially with several obsolescent spines. Palm 3.5-3.7 × (males), 3.6-4.3 × (females) longer than broad, 0.6-0.7 × as broad as high, 0.7-0.8 × as long as carpus, subequally broad medially and distally or very slightly broader medially, proximally narrowed; mesial margin sharply ridged, and shallowly or obsolescently serrated in males, more obsolescently so in females. Fingers directed straight forward or somewhat inclined laterally, gaping in proximal half, straightly fitting to each other in distal half when closed, relatively slender, distally spooned; movable finger 0.5-0.6 × (usually 0.6 x) length of palm, opposable margin with prominent blunt (truncate) process at midlength of gaping portion, distal to position of opposite process on fixed finger.
P2-4: Setose along prehensile margins of propodi and dactyli. Meri subequal on P2 and P3, P4 merus 0.4-0.5 × length of P3 merus; length-breadth ratio, 4.5-4.8 on P2, 4.7-4.8 on P3, 2.6-2.9 on P4; P2 merus subequal to length of carapace, 1.3 × length of P2 propodus, P3 merus 1.3 × length of P3 propodus, P4 merus 0.7 × length of P4 propodus. Carpi subequal in length on P2 and P3, P4 carpus 0.4 × length of P3 carpus; carpus-dactylus length ratio, 1.4-1.5 on P2, 1.4 on P3, 0.6 on P4. Propodi subequal on P2 and P3, P4 propodus 0.9 × length of P3 propodus; propodus-dactylus length ratio, 1.5 on P2, 1.6 on P3, 1.3-1.4 on P4; flexor margin concavely curving in lateral view, unarmed. Dactyli subequal on P2-4, dactylus-carpus length ratio, 0.7 on P2 and P3, 2.0 on P4; flexor margin with row of 13 or 14 (rarely 15) sharp slender spines proximally diminishing and subperpendicular to margin, ultimate and penultimate spines subequal.
Eggs. Number of eggs carried, 30; size, 1.00 × 1.24 mm - 1.12 × 1.35 mm (MNHN-IU-2014-17097).
Color. Male 4.7 mm from Bathus 3 Stn CP831, Norfolk Ridge (MNHN-IU-2014-17101): Reddish all over surface, abdomen translucent, P2-4 dactyli pale. Ovigerous female 4.6 mm from HalipRo 1 Stn CP854 (MNHN-IU-2014-17098): Reddish; abdomen, P2-3 dactyli and entire P4 pale.
REMARKS„ The species of Heteroptychus are classified into two groups by the presence or absence of articulation between the antennal scale and article 2: articulation present in H. anouchkae n. sp., H. apophysis n. sp., H. colini n. sp., H. edwardi (Kensley, 1981), H. paulae n. sp., and H. scambus (Benedict, 1902); articulation absent in H. brevis (Benedict, 1902), H. claudeae n. sp. and H. lemaitrei n. sp.
In the first group, H. anouchkae, H. apophysis and H. paulae share a long anterolateral spine of the carapace fully reaching or slightly falling short of the apex of the rostrum, whereas in the other species of the group, it is much shorter. Heteroptychus anouchkae differs from H. apophysis and H. paulae in having a much narrower, distally sharp pointed rostrum; the carapace lateral margin is more strongly convex around the posterior quarter rather than around posterior third; the anterolateral spine is directed somewhat dorsally instead of straight horizontal, the lateral orbital spine is consistently present; the anterior margin of sternite 3 bears a pair of submedian spines instead of a median notch.
description: Published as part of Baba, Keiji, 2018, Chirostylidae of the Western and Central Pacific: Uroptychus and a new genus (Crustacea: Decapoda: Anomura), pp. 1-612 in Mémoires du Muséum national d'Histoire naturelle 212 on pages 572-575, DOI: 10.5281/zenodo.3760976