Uroptychus webberi, Schnabel, 2009

Schnabel, Kareen E., 2009, A review of the New Zealand Chirostylidae (Anomura: Galatheoidea) with description of six new species from the Kermadec Islands, Zoological Journal of the Linnean Society 155 (3), pp. 542-582 : 572-575

UROPTYCHUS WEBBERI SP. NOV. ( FIG. 17 )

Type material: HOLOTYPE: ♀ ovig. (10.7 mm), Macauley Island , Kermadec Ridge, 30° 13.09′S, 178° 31.99′W, 610–640 m, 29.vii.1974, stn NZOI K846 ( NMNZ Cr. 012097).

Diagnosis: Carapace longer than broad; lateral margins parallel behind hepatic region, distal third with wide and distinct ridge, stout anterolateral spine; dorsal surface smooth, unarmed. Rostrum short, 0.2 times remaining carapace length, apex rounded, falling short of ocular peduncles. Sternal plastron as broad as long along midlength; sternite 3 with pair of submedian spines, strong anterolateral spines. Sternite 4 not reaching anterior end of sternite 3, smooth except for tuberculate transverse ridge. Antennal articles 4–5 unarmed; scale nearly twice as wide as article 4, reaching midlength of article 5, rounded. Pereopod 1 (cheliped) ischium with one stout distodorsal and one distoventral spine followed by row of granules. Pereopods 2–4 meri and carpi smooth along dorsal margins; propodi with six to ten spines along distal 0.5–0.6 of flexor margin, distal paired, margins not convex; dactyli strongly curved, without plumose setae, with loosely arranged spines, ultimate slender, longer than remaining spines, subequal width to remaining spines on flexor margin.

Description of holotype: Carapace: 1.2 times as long as broad (1.0 without rostrum), moderately convex from side to side. Dorsal surface smooth; cervical groove indistinct (faintly indicated), gastric region unarmed, only with very small granules in epigastric region. Frontal margin slightly excavate, relatively straight, relatively straight; outer orbital angle produced into small spine. Anterolateral margin with welldeveloped spine; lateral margin subparallel from posterior to hepatic region, widest at posterior threequarters, with distinct ridge in posterior third, unarmed but irregular. Posterior margin unarmed. Rostrum short, deflected ventrally, 0.2 times the length of remaining carapace, round apex; dorsal surface smooth, sparsely setose, and shallowly convex; lateral margins smooth. Pterygostomian flap lateral surface with few granules, anterior margin produced into a small spine.

Sternum: sternal plastron as wide as long, lateral extremities slightly divergent between sternites 5–7, serrated along lateral margins, surface smooth except for transverse row of granules on sternite 4. Anterior margin of sternite 3 with median notch flanked by pair of submedian spines; lateral margins produced to strong tooth. Sternite 4 two times as wide as sternite 3, anteriorly shallowly concave; anterolateral margin produced to tooth (not overreaching sternite 3 but reaching base of anterolateral tooth).

Abdomen: tergites smooth and unarmed, with very few setae. First abdominal tergite with shallow ridge at anterior margin. Pleural margins of segments 2–4 rounded; tergite 2 wide, slightly concave. Telson and tergite 6 two times as broad as long, distal portion emarginate, length 1.4 times that of proximal portion.

Eyes: cornea subglobular, 0.4 times length of ocular peduncle, overreaching rostrum.

Antennal peduncle: article 2 with blunt distolateral spine. Penultimate and ultimate articles unarmed distally. Ultimate article two times as long as penultimate. Antennal scale reaching to midlength of ultimate article; 2.1–2.2 times as long as wide.

Maxilliped 3: surface smooth, ischium without distal spines, 12 teeth on mesial ridge (four or five strong spines on basis). Merus, carpus, propodus, and dactylus unarmed.

Pereopod 1: stout, 2.7 times as long as carapace (3.3 excluding rostrum), surface smooth, fingers furnished with long setae. Ischium with dorsal and ventral spines distally and with row of spinules on ventral margin. Merus with rows of granules, ventral row of spines, with two ventral spines distally. Carpus sparsely tuberculate on ventral surface, with two small, round ventral spines distally, carpus 1.1–1.2 times as long as palm. Propodus with palm 2.4–2.5 times as long as high, unarmed. Dactylus 0.3 times as long as propodus, occlusal margins slightly gaping, denticulate, with distinct distal process.

Pereopods 2–4: decreasing in length and spination posteriorly (merus of P4 0.7 times merus of P2), surface slightly setose (distally furnished with long setae). Merus unarmed, 1.3–1.0 times as long as propodus (P2 longest). Carpus unarmed. Propodus 2.0–2.2 times as long as dactylus, extensor margin smooth. Flexor margin with 6–10 spines along distal half portion, distal paired. Dactylus curved; with 9–12 spines along entire length of flexor margin, ultimate slender and longest, preceded by subequal stout and rounded spines.

Ovum : 1.4–1.6 mm.

Remarks: Uroptychus webberi sp. nov. is most closely allied to those species with a smooth lateral carapace margin and smooth dorsum, narrow rostrum, anterior margin of sternum with submedian spines, smooth sternite 4 with anterolateral angle not reaching anterior margin of sternite 3, P2–4 propodi with a row of spines along the distal portion of the flexor margin (with distally paired spines), without convex margin, dactyli with regularly arranged blunt, triangular spines, and lacking plumose setae. This group of species includes Uroptychus litosus Ahyong & Poore, 2004 , Uroptychus nitidus ( Milne Edwards, 1880) , Uroptychus similis Baba, 1977 , and Uroptychus indicus Alcock, 1901 . Uroptychus webberi can be readily distinguished from these species by the parallel carapace margin with distinct and wide ridge along posterior third, round rostrum overreached by ocular peduncle and broader antennal scale (approximately half as wide as long).

The truncation of the rostrum could also be a result of damage and confirmation of this condition is pending collection of further specimens. Only the third pereopods remain attached to the body and the left second pereopod is missing in the holotype.

The record for Uroptychus webberi is closest to the known distribution of Uroptychus litosus , known from Tasmania. Uroptychus nitidus has a known Atlantic and north-western Pacific distribution range, Uroptychus similis has been recorded from Midway Island, Hawaii, and Uroptychus indicus is widespread in the Indian Ocean.

Distribution: Off Macauley Island, Kermadec Islands, 610–640 m ( Fig. 7 ).

Etymology: Named in honour of Richard Webber, Curator of Crustacea, National Museum of New Zealand Te Papa Tongarewa, Wellington for his contributions to New Zealand crustacean taxonomy, for providing material for this work, and his general support.

Figures

Figure 7. Records of Uroptychus kaitara sp. nov., Uroptychus paku sp. nov., Uroptychus rutua sp. nov., Uroptychus toka sp. nov., Uroptychus webberi sp. nov., and Uroptychus yaldwyni sp. nov. around the Kermadec Islands, New Zealand. 250, 1000, and 2500 m bathymetric contours are shown.

Figure 17. Uroptychus webberi sp. nov., holotype, ♀ ovig., NMNZ Cr. 012097: A, carapace and abdomen dorsal, setae omitted; B, carapace and abdomen, lateral, setae omitted; C, sternal plastron; D, telson, setae omitted; E, antenna, right, ventral; F, endopod of third maxilliped, left, lateral, setae omitted. G, mesial ridge, left; H, right cheliped, dorsal; I, right cheliped, ischium and merus, lateral; J–L, right pereopods 2–4; M, dactylus and distal portion of propodus of right pereopod 3, lateral. Scale bars = 2 mm.