Uroptychus singularis, Baba, Keiji & Lin, Chia-Wei, 2008

Baba, Keiji & Lin, Chia-Wei, 2008, Five new species of chirostylid crustaceans (Crustacea: Decapoda: Anomura: Chirostylidae) from Taiwan, Zootaxa 1919, pp. 1-24 : 18-23

publication ID	https://doi.org/ 10.5281/zenodo.184667
DOI	https://doi.org/10.5281/zenodo.6228977
persistent identifier	https://treatment.plazi.org/id/03B887DA-5604-FFA9-FF48-FC4FFD25FCF2
treatment provided by	Plazi
scientific name	Uroptychus singularis
status	sp. nov.

Treatment

Uroptychus singularis View in CoL sp. nov.

( Figs. 11 View FIGURE 11 , 12 View FIGURE 12 , 13 View FIGURE 13. A D)

Type material. Holotype: NTOU A00862 View Materials , male (7.1) mm, SW Taiwan, Stn CP179, 22°21.22’N, 119°54.78’E, 1212– 1063 m, gorgonian host, 25 Aug 2002. Paratypes: NTOU A00863 View Materials , 17 males (4.0–8.0 mm), 9 ovigerous females (5.7–7.0 mm), 16 females (4.2–7.3 mm), station data as for the holotype, 4 males and 6 females with rhizocephalan externa; NTOU A00864 View Materials , 1 ovigerous female (6.6 mm), 1 female (6.4 mm), SW Taiwan, Stn CP134, 22°16.56’N, 120°6.11’E, 736–1040 m, gorgonian host, 22 Nov 2001; NTOU A00865 View Materials , 1 male (6.8 mm), SW Taiwan, Stn CD135, 22°17.21’N, 120°0.28’E, 961–1112 m, 22 Nov 2001; NTOU A00866 View Materials , 3 males (5.9–7.8 mm), 2 ovigerous females (6.5–7.1 mm), 4 females (5.9–7.1 mm), Stn CD136, 22°7.75’N, 120°0.87’E, 1211– 998 m, sticky mud, 22 Nov 2001; NTOU A00867 View Materials , 5 males (4.3–7.4 mm), 2 ovigerous females (6.1, 6.3 mm), SW Taiwan, Stn CD141, 22°12.04’N, 119°59.96’E, 1110– 985 m, coral fans and antique pot, gorgonian host, 24 Nov 2001; NTOU A00868 View Materials , 4 males (5.3–7.8 mm), 2 ovigerous females (7.1–7.2 mm), 1 female (8.0 mm), NE Taiwan, Stn CP235, 25°22.95’N, 122°43.63’E, 765–806 m, many small mud tubes, woods and sponges, 22 Jul 2004; NTOU A00869 View Materials , 1 male (6.8 mm), SW Taiwan, Stn CP 300, 22°17.156’N, 119°59.963’E, 960–972 m, 11 Aug 2005; NTOU A00870 View Materials , 2 males (7.0, 7.1 mm), 5 ovigerous females (5.2–7.0 mm), 6 females (5.0– 7.2 mm), SW Taiwan, Stn PCP334, 22°16.713’N, 120°0.114’E, 994– 975 m, many sponges, gorgonian host, 5 Oct 2005; NTOU A00871 View Materials , 12 males (3.2–7.7 mm), 4 ovigerous females (6.3–7.5 mm), 7 females (3.9–7.2 mm), SW Taiwan, Stn IK341, 22°11.707’N, 120°10.483’E, 824– 779 m, gorgonian host, 7 Mar 2006; NTOU A00872 View Materials , 4 males (6.4–7.1 mm), 6 ovigerous females (5.6–7.5 mm), 2 females (6.2, 6.8 mm), SW Taiwan, Stn PCP344, 22°15.952’N, 120°0.110’E, 995– 1073 m, many sponges, some mud flasks, 8 Mar. 2006; NTOU A00873 View Materials , 1 ovigerous female (5.8 mm), SW Taiwan, Stn PCP345, 22°11.886’N, 120°0.526’E, 1165–1197 m, 8 Mar 2006.

Diagnosis. Carapace distinctly longer than broad, dorsally smooth, with pair of small epigastric spines. Anterolateral spine small, not reaching distal end of antennal article 2; small spine at anterior end of branchial margin. Pterygostomian flap anteriorly angular, ending in small spine. Excavated sternum anteriorly sharp angular between close bases of Mxp1, surface with small spine in center. Sternite 3 with pair of submedian spines separated by V-shaped notch. Sternite 4 anterolaterally with small spine. Eyes relatively broad, cornea not inflated. Antennal article 2 with distolateral spine; antennal scale slightly overreaching midlength of article 5; articles 4 and 5 unarmed, article 5 about twice as long as article 4, antennal flagellum not reaching distal end of P1 merus. Mxp3 unarmed on merus and carpus. P1 relatively slender, unarmed; ischium with short dorsal spine, without subterminal spine on ventromesial margin; merus slightly longer than carapace. P2–4 slen- der, with long setae on carpi and propodi, unarmed on meri and carpi, P4 much smaller than P2 and P3; P2 merus subequal to P3 merus, distinctly shorter than carapace. Carpi longer than dactyli, half as long as propodi or slightly more than so on P2 and P3, nearly half as long on P4. Propodi having flexor margin with 5–7 spines on P2, 4–6 on P3 and P4, terminal one single, not paired. Dactyli strongly curving proximally, with 9– 11 spines oriented to parallel to flexor margin, terminal spine much larger.

Description. Carapace 1.1–1.2 [1.2] times as long as broad. Dorsal surface convex from side to side, distinctly elevated from level of rostral base, feebly excavated between indistinct gastric and cardiac regions, glabrous and smooth. Gastric region with pair of small spines behind eyes usually distinct, rarely obsolescent or absent [distinct]. Lateral margins divergent posteriorly, weakly convex posteriorly; small spine at anterior end of branchial region; elevated ridge along posterior third. Anterolateral spine small, located posterior to level of lateral orbital spine, not reaching distal end of article 2 of antennal peduncle. Rostrum straight, directed somewhat dorsally, relatively broad at base, sharp long triangular, with interior angle of 21–28° [23°], length 0.4 that of rest of carapace; dorsal surface flattish; lateral margins entire. Lateral limit of orbit angular, ending in very small spine. Pterygostomian flap smooth on surface, anteriorly angular, ending in small spine.

Excavated sternum sharply produced anteriorly, surface with small spine in center. Sternal plastron as long as or slightly shorter than [as long as] broad, lateral extremities subparallel or slightly divergent posteriorly between sternites 4–7 [subparallel]. Sternite 3 moderately depressed, anterior margin excavated in broad V-shape, with submedian spines of good size separated by shallow V-shaped notch; anterolateral margin with small spine. Sternite 4 with anterolateral margin straight or slightly convex [straight], steeply oblique, anteriorly angular and spiniform, followed by posteriorly diminishing, obsolescent denticles, anterolateral margin 1.3–1.5 [1.4] length of posterolateral margin.

Abdominal somites smooth and glabrous. Somite 1 gently convex from anterior to posterior end, without sharp ridge. Pleuron of somite 2 with concavely divergent lateral margins ending in rounded or bluntly produced corner. Somites 3 and 4 also with bluntly angular lateral margin. Telson 0.6–0.7 [0.6] times as long as broad; posterior lobe moderately emarginate on posterior margin, length 1.5–1.8 [1.7] times that of anterior lobe.

Eyes broad relative to length, 1.4–1.6 [1.4] times longer than broad, exceeding 3/4 length of rostrum, proximally somewhat narrowed, lateral margin slightly convex, mesial margin somewhat convex at midlength of peduncle without cornea. Cornea not dilated, length subequal to that of peduncle.

Ultimate article of antennule 1.7–2.3 [2.2] times longer than broad. Antennal peduncles terminating in distal end of cornea. Article 2 with distinct short spine. Antennal scale slightly broader than article 5, slightly overreaching midlength of article 5. Distal 2 articles unarmed; article 5 1.7–2.2 [2.2] times longer than article 4; breadth 0.4–0.5 [0.4] that of antennular ultimate article. Flagellum consisting of 9–13 [13] segments, falling far short of distal end of P1 merus.

Mxps1 close to each other at base. Mxp3 barely setose on lateral surface. Basis with 4–6 [5] denticles on mesial ridge. Ischium with 11–14 [12–13] denticles on crista dentata, flexor margin not rounded distally. Merus unarmed, moderately thick, flexor face with rounded ridge. Carpus unarmed.

P1 relatively slender, 4.7–5.5 [6.2] (in males), 4.5–5.3 (in females) times longer than carapace, barely setose except for fingers. Ischium dorsally with short triangular spine; ventromesial margin with a few very small proximal spines, lacking subterminal spine. Merus dorsally smooth, ventrally with 2 rows of very small spines; length 1.1–1.3 [1.3] times that of carapace. Carpus smooth, 1.2–1.5 [1.5] times longer than merus, subcylindrical. Palm also smooth, 3.2–3.6 [3.6] (in males), 3.6–4.4 (in females) times longer than broad, length 0.8–1.0 [0.9] that of carpus; mesial and lateral margins nearly subparallel. Fingers straight in lateral view, setose, relatively broad, crossing, distally ending in small incurved spine; movable finger 0.4–0.5 [0.4] as long as palm; in males, broad truncate process proximal to midlength of opposing margin; in females, opposable margins slightly sinuous, proximal process of movable finger fitting to opposing concavity of fixed finger when closed.

P2–4 sparingly with long setae, slender, unarmed except for propodi and dactyli. Meri well compressed, with mesial surface flattish, ventral margins sharply keeled; lengths subequal on P2 and P3, much smaller on P4 (P4 merus 0.6–0.7 [0.6] P3 merus); breadths subequal on P2 and P3 or slightly greater on P3 than on P2, P4 merus 0.6–0.7 [0.7] as broad as P3 merus; length-breadth ratio, 4.1–4.9 [4.6] on P2, 4.1–4.8 [4.5] on P3, 3.6–4.8 [4.1] on P4; P2 merus 0.8 length of carapace, 1.1–1.2 [1.2] times longer than P2 propodus, P3 merus 1.0–1.1 [1.1] times longer than P3 propodus, P4 merus 0.8–0.9 [0.9] length of P4 propodus. Carpi subequal on P2 and P3 or slightly longer on P3, much shorter on P4 (P4 carpus 0.7–0.8 [0.7] P3 carpus); carpus-propodus length ratio, 0.49–0.58 [0.54] on P2, 0.46–0.54 [0.49] on P3, 0.44–0.52 [0.47] on P4. Propodi longest on P3, shorter on P4 than on P2; length-breadth ratio 4.3–4.7 [4.6] on P2, 4.3–5.1 [5.1] on P3, 4.3–5.0 [4.9] on P4; flexor margin with row of spines (5–7 [5] on P2, 4–6 [5] on P3, 4–6 [4] on P4) at most on distal half, distalmost (terminal) single, shorter than penultimate. Dactyli longest on P3, subequal on P2 and P4 or slightly longer on P4 than on P2; length 0.37–0.44 [0.37] that of propodus on P2, 0.36–0.46 [0.38] on P3, 0.43–0.49 [0.45] on P4; flexor margins strongly curving at proximal third, with row of 9–11 [10] spines oriented parallel to margin, terminal one largest.

Eggs: Up to 28 eggs carried; size, 1.0 mm x 1.0 mm – 1.6 mm x 2.1 mm.

Color in life. Pale orange overall. Deep orange viscera visible through gastric region of carapace.

Etymology. From the Latin singularis (single), alluding to a single spine at the end of P2–4 propodi, not paired as in the close species U. australis .

Remarks. The species is close to U. australis ( Henderson, 1885) in having paired epigastric spines, very short and slender P4, and P2–4 dactyli with inclined spines almost contiguous to or oriented parallel to the flexor margin. The new species is readily distinguished from that species by the P2–4 propodi with the flexor margins ending in a single instead of a pair of spines, and the antennal scale only slightly overreaches the midlength instead of reaching the end of antennal article 5.

Distribution. S and NE Taiwan, 736–1212 m.