Uroptychus orientalis Baba & Lin, 2008, sp. nov.
Creators: name: Baba, Keiji
name: Lin, Chia-Wei
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Chirostylidae
Uroptychus
Uroptychus orientalis

description: Uroptychus orientalis sp. nov.
(Figs. 8, 9, 13 C)
Uroptychus nitidus occidentalis. — Baba, 1973: 120, fig. 2, pl. 4, fig. 1 [not U. nitidus occidentalis Faxon, 1893].
Type material. Holotype: NTOU A00853, ovigerous female (11.2 mm), SW Taiwan, Stn CD230, 22°19.32’N, 120°3.3’E, 795–840 m, sticky mud, 30 Aug 2003. Paratypes: NTOU A00854, 4 ovigerous female (8.9–10.7 mm), SW Taiwan, Stn CD 134, 22°16.56’N, 120°6.11’E, 736–1040 m, 22 Nov 2001, gorgonian host; NTOU A00855, 1 female (9.0 mm), 1 ovigerous female (10.7 mm), SW Taiwan, Stn CD135, 22°17.21’N, 120°0.28’E, 961–1112 m, 22 Nov. 2001; NTOU A00856, 1 male (8.9 mm), 1 ovigerous female (9.7 mm), SW Taiwan, Stn CD229, 22°13.35’N, 120°1.9’E, 1060– 880m, big squid, 30 Aug 2003; NTOU A00857, 1 ovigerous female (10.7 mm), SW Taiwan, Stn CP300, 22°17.156’N, 119°59.963’E, 960–972 m, 11 Aug 2005; NTOU A00858, 1 ovigerous female (10.3 mm), South China Sea, SW of Taiwan, Stn CD321, 20°43.053’N, 117°33.258’E, 951–973 m, 19 Aug 2005, collected together with many Nematocarcinus sp., Plesionika nessisi and Uroptychus anatonus sp. nov.; NTOU A00859, 1 male (8.9 mm), SW Taiwan, Stn PCP333, 22°16.502’N, 120°2.242’E, 889–1037 m, many sponges, 5 Oct 2005; NTOU A00860, 2 males (7.4, 7.4 mm), SW Taiwan, Stn PCP334, 22°16.713’N, 120°0.114’E, 994– 975 m, many sponges, 5 Oct 2005; NTOU A00861, 1 ovigerous female (10.0 mm), SW Taiwan, Stn PCP343, 22°15.699’N, 120°2.131’E, 945– 1059 m, many sponges, 8 Mar 2006.
Diagnosis. Carapace slightly longer than broad, dorsal surface feebly granulose on lateral portion; pair of granulate epigastric ridges posterior to ocular peduncles. Rostrum slightly upturned distally. Pterygostomian flap anteriorly rounded, with tiny spine. Excavated sternum anteriorly sharp angular between close and nearly contiguous bases of Mxp1; surface with small spine in center. Sternite 3 with pair of submedian spines separated by narrow notch. Sternite 4 with distinct anterolateral spine followed by low denticles. Eyes distinctly longer than broad, cornea somewhat inflated. Antennal article 2 with sharp distolateral spine; antennal scale reaching at most distal fourth of article 5; articles 4 and 5 unarmed. Mxp3 spineless on merus and carpus. P1 relatively slender, smooth; ischium dorsally with short spine, ventrally without subterminal spine on mesial margin; merus slightly longer than carapace. P2–4 moderately compressed, with long setae on distal parts of carpi and whole propodi; meri successively shorter and narrower posteriorly; P2 merus slightly shorter than carapace; carpi successively shorter posteriorly, slightly more than half (on P2–3) or about half (on P4) as long as propodi; propodi slightly broadened distally, flexor margin ending in pair of spines preceded by 5–7, 4–6, 4 or 5 spines on P2, P3, P4 respectively; dactyli less than half length of propodi, flexor margin with 9–11 proximally diminishing triangular spines, ultimate and penultimate subequal.
Description. Carapace 1.1 times longer than broad. Dorsal surface moderately convex from side to side and from anterior to posterior end, with shallow depression between indistinct gastric and cardiac regions. Gastric region anteriorly sloping down in profile to midpoint of rostrum; epigastric region with pair of granulate ridges posterior to ocular peduncles; tiny scattered tubercles on lateral part (on hepatic and lateral branchial regions). Lateral margins slightly convexly divergent posteriorly, with granules or granulate short ridges, anterior end of branchial margin somewhat elevated; distinct ridge along posterior 1/5 of length. Rostrum sharp triangular, with interior angle of 22–30° [27°]; distally curving slightly dorsally; dorsal surface flattish, length 0.4–0.5 [0.4] that of carapace. Lateral orbital angle angular with small spine. Pterygostomian flap with tiny tubercles in median part, anterior margin rounded, with very small spine.
Excavated sternum anteriorly angular, well produced, surface with small spine in center. Sternal plastron 0.9–1.0 [0.9] as long as broad. Sternite 3 depressed well, anterior margin deeply excavated, with pair of submedian spines separated by narrow notch; anterolateral angle bluntly angular; anterolateral margin with small spine on each side. Sternite 4 with anterolateral margin 1.5 times longer than posterolateral margin, anteriorly with moderate-sized spine reaching lateral small spine on sternite 3, followed by a few to several weak processes.
Abdomen smooth and glabrous. Abdominal somite 1 without transverse ridge. Somite 2 having pleural lateral margins anteriorly and posteriorly rounded, concavely divergent posteriorly. Pleura of somites 3–4 tapering, ending in blunt end. Telson 0.5–0.6 [0.5] as long as broad; posterior lobe 1.4–1.8 [1.8] times longer than anterior lobe, posterior margin emarginate.
Eyes ending in distal third of rostrum, distally somewhat swollen, mesial margin concave on peduncle. Cornea slightly more swollen than distal part of peduncle, about as long as peduncle.
Ultimate article of antennule 2.5–2.9 [2.9] times longer than broad. Antennal peduncle terminating in distal end of cornea. Article 2 with strong distolateral spine. Antennal scale 1.4–1.7 [1.4] times broader than article 5, varying from terminating at midlength to reaching distal fourth [distal fourth] of article 5. Distal 2 articles unarmed. Article 5 1.8–2.1 [1.8] times longer than article 4, breadth 0.4–0.5 [0.4] that of antennular ultimate article. Flagellum consisting of 16–20 [20] segments, varying from slightly falling short of to slightly overreaching [slightly falling short of] end of P1 merus.
Mxps1 close to each other. Mxp3 barely setose on lateral surface. Basis with 4–6 [6] denticles on mesial ridge. Ischium with 17–24 [24] denticles on crista dentata, flexor margin not rounded on distal end. Merus with smooth, moderately ridged flexor margin, unarmed. Carpus unarmed but [very tiny spine in holotype] on proximal extensor margin.
P1 relatively slender, 4.8–4.9 (males), 4.3–4.5 [4.5] (females) times longer than carapace, smooth, barely setose except for fingers. Ischium dorsally with short spine, ventromesially lacking subterminal spine. Merus 1.1–1.3 [1.1] times longer than carapace, distally broadened, ventral surface with longitudinal groove flanked by row of low spines. Carpus 1.2–1.3 [1.3] times longer than merus, 0.75–[0.8] as high as broad, ventrally with a few small blunt spines distally. Palm 2.8–3.0 times longer than broad in males, 3.3–3.5 [3.5] in females, length 0.73–0.89 [0.74] that of carpus. Fingers broad relative to length, moderately depressed, distally ending in incurved spine; proximally gaping in males, not gaping in females. Fixed finger broadest at midlength, opposable margin bluntly angular at midlength. Movable finger 0.58–0.59 length of palm in males, 0.55–0.60 [0.55] in females, opposable margin with low truncate, broad (disto-proximally) process fitting to proximal third of opposing margin of fixed finger.
P2–4 moderately compressed, setose distally, setae on propodi and distal parts of carpi very long. Meri successively shorter posteriorly (P3 merus 0.9 P2 merus, P4 merus 0.8 P3 merus); breadth also successively slightly decreasing posteriorly; length-breadth ratio, 5.2–5.6 [5.5], 4.8–5.5 [5.2], 4.2–4.9 [4.9] on P2, P3, P4 respectively; merus-propodus length ratio, 1.2–1.3 [1.2] on P2, 1.1 on P3, 0.9 on P4; P2 merus 0.8–0.9 [0.9] length of carapace; unarmed. Carpi successively shorter posteriorly (P3 carpus 0.9–0.98 [0.9] P2 carpus, P4 carpus 0.8–0.9 [0.9] P3 carpus); carpus-propodus length ratio, 0.54–0.59 [0.59] on P2, 0.54–0.57 [0.54] on P3, 0.47–0.51 [0.49] on P4. Propodi slightly longer on P3 than on P2 and P4, subequal on P3 and P4 and slightly longer on P2, subequal on P2–4, or [successively slightly shorter posteriorly]; slightly broadened distally; length-breadth ratio, 5.3–5.8 [5.8] on P2, 5.1–6.0 [5.4] on P3, 5.4–6.2 [6.0] on P4; flexor margin ending in pair of spines preceded by 5–7 [7] (on P2), 4–6 [5–6] (on P3), 4–5 [4] (on P4) spines at most on distal half. Dactyli subequal, moderately curving, flexor margin with 9–11 [11] proximally diminishing triangular spines, ultimate and penultimate subequal; dactylus-propodus length ratio, 0.38–0.44 [0.38], 0.39–0.45 [0.39], 0.39– 0.44 [0.39] that of propodus on P2, P3, P4 respectively.
Eggs: Up to 16 eggs carried [in holotype, 8 larvae + 12 eggs]; size, 1.1 mm x 1.2 mm –1.8 x 1.9 mm.
Color in life. Pale orange overall.
Etymology. From the Latin orientalis (eastern), the antonym of occidentalis (western), alluding to the occurrence of the new species in the oriental region of Asia (= western Pacific). The close relative U. occidentalis is known from the “western” part of North and South American continents (= the eastern Pacific).
Remarks. Examination of the material reported under U. nitidus occidentalis by Baba (1973) showed that it is identical with this new species. Baba (2005) believed that Uroptychus nitidus (A. Milne Edwards, 1880) was a variable species. However, he examined in 2007 material in the collections of the Smithsonian Institution and found that U. nitidus from the western Atlantic and U. nitidus concolor from the eastern Atlantic are distinct species; Uroptychus nitidus forms A and B of Chace, (1942) are also different species and distinct from U. nitidus; and the material reported by Kensley from South Africa under U. nitidus is another undescribed species (Baba, unpublished).
Uroptychus nitidus occidentalis Faxon, from 838 m, was described from the Gulf of Panama, but the type material has not been located. Baba examined the following material of U. nitidus occidentalis in the collection of the Smithsonian Institution and found them different from U. nitidus at the specific level: USNM 29170, Albatross stn 2818, NE of Indefatigable Island, Galapagos, 717 m, 15 Apr 1888 [between Santa Cruz and San Cristobal Islands, Galapagos Islands, 00°29’00”S, 89°54’30”W, 717 m], 22 males (4.0– 10.4 mm), 23 ovigerous females (7.0– 10.5 mm), 7 females (3.8–9.0 mm), on Chrysogorgia fruticosa (Studer).
The new species strongly resembles the specimens of U. occidentalis Faxon, 1893 that KB examined (see Fig. 10) but the two species can be distinguished by the following: the rostrum in U. orientalis is directed dorsally, not horizontal as U. occidentalis; the antennal scale in U. orientalis usually terminates at the midlength and occasionally reaches the distal three-fourths of the antennal article 5, whereas in U. occidentalis it is usually overreaches the distal three-fourths and never reaches the distal end of the article 5; the ultimate spine of the P2–4 dactyli in U. orientalis is subequal to instead of distinctly more slender than the penultimate as in U. occidentalis; and P2–4 meri in U. orientalis is not so strongly depressed as in U. occidentalis.
The new species is also close to U. litosus Ahyong & Poore, 2004 from Tasmania, from which it is differentiated by the antennal scale reaching at most distal three-fourths instead of fully reaching the distal end of article 5, the rostrum directed dorsally instead of horizontal, the pterygostomian flap with very small instead of well-developed spine on the anterior end.
Distribution. Sagami Bay (Japan), SW Taiwan and South China Sea SW of Taiwan, in 795–1112 m.
description: Published as part of Baba, Keiji & Lin, Chia-Wei, 2008, Five new species of chirostylid crustaceans (Crustacea: Decapoda: Anomura: Chirostylidae) from Taiwan, pp. 1-24 in Zootaxa 1919 on pages 12-18, DOI: 10.5281/zenodo.184667