Uroptychus kaitara, 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 : 553-555

UROPTYCHUS KAITARA SP. NOV. ( FIG. 6 )

Type material: HOLOTYPE: ♀ ovig. (3.5 mm), Macauley Island , Kermadec Ridge, 30° 17.59′S, 178° 25.30′W, 398–412 m, 28.vii.1974, stn NZOI K840 ( NMNZ Cr. 012081).

Diagnosis: Carapace longer than broad, entirely covered with small spines on dorsal and lateral surfaces; dorsal surface sculptured with epigastric and cardiac regions inflated; lateral margins subparallel. Anterior margin of abdominal tergite 2 with scattered small spines. Sternal plastron approximately as long as wide along midlength. Antennal peduncle articles subequal in length, penultimate article with long distal spine (rounded, lobe-like); antennal scale reaching midlength of ultimate peduncle article. Maxilliped 3 carpus with three spines along extensor margin. Pereopod 1 (cheliped) slender and unarmed except for small distodorsal spine on ischium. Pereopods 2–4 merus with five to seven spines on dorsal crest; carpus unarmed; propodus with distal pair of spines only, without marked projection; dactylus not truncate distally, with five or six acute triangular spines along flexor margin, loosely arranged, perpendicular to flexor margin, and very small (approximately quarter width of penultimate) ultimate spine, penultimate largest.

Description of holotype: Carapace: 1.2 times as long as broad (0.8 without rostrum), moderately convex from side to side. Dorsal surface covered with small spines; lateral epigastric area and cardiac region broadly inflated; cervical groove deep and distinct. Frontal margin deeply excavate; outer orbital angle produced to a sharp tooth. Anterolateral margin with small spine, slightly posterior to orbital spine; lateral margin subparallel, slightly wider posteriorly; with 21 or 22 small spines excluding anterolateral spine, hepatic region with five or six lateral spines, six spines in anterior branchial region, ten spines in posterior branchial region. Posterior margin with transverse row of small spines. Rostrum triangular, slightly deflected ventrally, length 0.4 times that of remaining carapace; dorsal surface excavate and with small spines on posterior two-thirds; lateral margins smooth. Pterygostomian flap lateral surface covered with small spines, anterior margin produced into a spine.

Sternum: sternal plastron 1.1 times as wide as long, lateral extremities subparallel between sternites 5–7 (sternite 4 widest), surface smooth and unarmed. Anterior margin with median notch flanked by pair of incurved submedian spines and produced medially; lateral margins rounded. Sternite 4 two times as wide as sternite 3, anteriorly deeply concave but shallow; anterolateral margin rounded with blunt round terminus.

Abdomen: tergites smooth and unarmed except for scattered small spines in anterior and lateral portions of tergite 2. First abdominal tergite with ridge at posterior margin; tergites 2–4 without transverse ridges or grooves. Pleural margins of segments 2 to 4 rounded, tergite 2 wide, slightly concave. Telson 1.7 times as broad as long; posterior portions equal length of anterior portion.

Eyes: smooth. Cornea subglobular, 0.5 times length of ocular peduncle, reaching distal quarter of rostrum.

Antennal peduncle: Article 2 with distinct outer spine, reaching nearly to midlength of penultimate article of peduncle. Penultimate article with very blunt and lobe-like distal spine (left peduncle with additional, ventral spine). Ultimate article unarmed, 1.1 times as long as penultimate. Antennal scale reaching to midlength of ultimate article; 3.7–4.0 times as long as wide.

Maxilliped 3: surface smooth. Ischium without distal spines, two teeth on basis of mesial ridge, otherwise obsolescent teeth. Merus extensor margin with distal spine, very blunt, lobe-like; flexor margin with one large median spine. Carpus extensor margin with two or three blunt spines, distal spine absent; propodus and dactylus unarmed.

Pereopod 1: slender, 3.9 times as long as carapace, surface scattered with long setae. Ischium with dorsal distal spine only. Merus and carpus unarmed; carpal length 0.9–1.0 times as long as palm. Propodus with palm 4.8–5.4 times as long as high, unarmed. Length of dactylus 2.5–2.9 times as long as propodus, occlusal margins slightly gaping on right, with median process, not gaping on left cheliped.

Pereopods 2–4: similar. Merus 0.8–1.0 times as long as propodus; dorsal margin with four to seven spines on dorsal crest (including distal spine); ventral margin without spines. Carpus unarmed. Propodus 1.7–2.0 times as long as dactylus; extensor margin smooth; flexor margin with only distal pair of spines. Dactylus straight; flexor margin with spines along distal two-thirds; with five or six spines along flexor margin (excluding distal spine), stout triangular, perpendicular to margin; penultimate spine largest; distal spine very small.

Variation and remarks: Uroptychus kaitara sp. nov. belongs in a group of species with an unarmed dorsal carapace, carapace lateral margin with more than three spines, P2–4 propodi without marked distal projection, dactyli penultimate spine extremely broader than ultimate, penultimate not much larger than antepenultimate, remaining spines loosely arranged; a group of species that comprises Uroptychus inclinis Baba, 2005 , Uroptychus tridentatus ( Henderson, 1885) , and Uroptychus zezuensis Kim, 1972 . It differs, however, from all these species in having the entire dorsal surface and entire lateral margin of the carapace and anterior margin of tergite 2 covered with small spines ( Uroptychus inclinis and Uroptychus tridentatus have seven and Uroptychus zezuensis bears five distinct spines along the anterior lateral margin, the posterior third and posterior carapace margin are unarmed). The dorsal surface is also more sculptured in Uroptychus kaitara with the epigastric and branchial region broadly inflated and separated by a deep and distinct cervical groove ( Uroptychus inclinis , Uroptychus tridentatus , and Uroptychus zezuensis are evenly convex with an indistinct cervical groove). Of the closely allied species, only Uroptychus tridentatus with its wide western Pacific distribution shares the distribution range of Uroptychus kaitara ; Uroptychus inclinis is only known from the Kei Islands, Indonesia and Uroptychus zezuensis has only been recorded from the northwestern Pacific.

Uroptychus kaitara sp. nov. can also be allied to species that have spines along the carapace lateral margin, spines across the entire dorsal carapace surface, and a smooth cheliped palm, such as Uroptychus paku sp. nov., Uroptychus fusimanus Alcock & Anderson, 1899 , and Uroptychus sexspinosus Balss, 1913 . All of these species, however, have scattered large spines on an otherwise smooth carapace and abdomen, whereas Uroptychus kaitara is densely covered with small spines including the second tergite of the abdomen. Uroptychus kaitara further differs from these three species in having spines along the dorsal margin of P2–4 meri only, whereas Uroptychus paku and Uroptychus sexspinosus have spines along the merus and carpus and Uroptychus fusimanus has unarmed ambulatory legs.

The left palm of the cheliped of the holotype is considerably larger than the right. All legs of the holotype are detached.

Distribution: Off Macauley Island, Kermadec Islands; 398–412 m ( Fig. 7 ).

Etymology: Kaitara is the Māori word for coarse, with reference to the tuberculate dorsal surface.

Figures

Figure 6. Uroptychus kaitara sp. nov. holotype, ♀ ovig., NMNZ Cr. 012081: A, carapace and abdomen dorsal, setae omitted; B, carapace and abdomen, lateral, setae omitted; C, sternal plastron; D, telson, setae omitted; E, antenna, left, ventral; F, antenna, right, ventral; G, antenna, right, lateral; H, endopod of third maxilliped, right, lateral, setae omitted; I, mesial ridge, right; J, right cheliped, dorsal; K–M, right pereopods 2–4; N, dactylus and distal portion of propodus of right pereopod 2, lateral. Scale bars = 2 mm.

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.