Uroptychus uncifer ( A. Milne-Edwards, 1880 )

Baba, Keiji & Wicksten, Mary K., 2017, Uroptychus nitidus (A. Milne-Edwards, 1880) and related species (Crustacea: Decapoda: Anomura: Chirostylidae) from the western Atlantic, Zootaxa 4221 (3), pp. 251-290 : 281-287

Uroptychus uncifer ( A. Milne-Edwards, 1880)

( Figs. 20–22 , 3 D)

Diptychus uncifer A. Milne-Edwards, 1880: 63 .

Diptychus nitidus A. Milne-Edwards, 1880: 62 (part).— Milne-Edwards & Bouvier 1897: 140, pl. 11: figs. 1–2, pl. 12: figs. 17– 29.

Uroptychus uncifer .— Benedict 1901: 148.— Chace 1942: 18, fig. 7 (part).— Lemaitre 1984: 427.—de Melo 1999: 170, fig. 104.— Poupin & Corbari 2016: 38 –39, fig. 9f.

Type material. Lectotype: MCZ CRU- 2674, 1 male (CL 4.1), off coast of Barbados, 13°5’0”N, 59°39’18”W, 140 fms [256 m], 10 Mar. 1879, Blake Sta. 299.

Paralectotype: MCZ CRU- 2716, 1 male (CL 5.3), off Milligan’s Key , St. Vincent, 13°7’55”N, 61°5’36”W, 124 fms [227 m], 3 Mar. 1879, Blake Sta. 269.

Other material examined: MCZ CRU- 2713, 1 male (CL 2.7), off Barbados, 13°2’36”N, 59°37’45”W, 123 fms, 10 Mar. 1879, Blake Sta. 297 . MCZ CRU- 2832, 1 female (CL 3.0), off St. Vincent, 13°6´45”N, 61°6´55”W, 88 fms [161 m], 21 Feb. 1879, Blake Sta. 232 . USNM 29175, 1 ov. female (CL 6.4), Mayaguez Harbor, Puerto Rico, 220 fms [402 m], U.S.F.C. Fish Hawk Sta. 6070.

Description. Carapace: [As long as], very slightly shorter or very slightly longer than broad; greatest breadth 1.6 × distance between anterolateral spines. Dorsal surface smooth, glabrous and unarmed, somewhat convex from anterior to posterior in profile, [without] or with depression between gastric and cardiac regions. Lateral margins smooth, divergent posteriorly, convex around branchial region, distinctly ridged along [posterior third] or posterior two-thirds. Anterolateral spine well developed, directed anteriorly, situated slightly posterior to position of small lateral orbital spine, overreaching tip of that spine. Rostrum [0.8]–0.9 × as long as broad, relatively broad, with interior angle of 28–[32]°, straight horizontal, slightly overreaching eye; length [0.6]–0.7 × (0.4 × in smallest male, CL 2.7 mm) that of remaining carapace, breadth slightly more than half that of carapace measured at posterior margin; lateral margins proximally concave; dorsal surface concave. Pterygostomian flap anteriorly somewhat roundish, produced to distinct spine.

Sternum: Excavated sternum sharply produced anteriorly, surface with small spine in center. Sternal plastron about as long as broad, sternites 4–7 successively broader posteriorly, sternites 6 and 7 subequally broad. Sternite 3 well depressed, moderately excavated anterior margin bearing 2 submedian spines separated by notch, laterally blunt; anterolateral end with distinct low spine. Sternite 4 anterolateral margin anteriorly ending in short, stout, anterolaterally directed spine not reaching anterior end of sternite 3, length 2.0 × that of posterolateral margin. Sternite 5 anterolateral margin1.5 × longer than posterolateral margin of sternite 4.

Abdomen: Tergites smooth and glabrous. Somite 1 convex from anterior to posterior, not transversely ridged. Somite 2 tergite 2.6–[2.7] × broader than long; pleuron posterolaterally ending in rounded terminus, lateral margins somewhat concavely divergent posteriorly. Pleura of somites 3 and 4 laterally rounded. Telson [about half as long as broad] or slightly less than so; posterior plate emarginate on posterior margin, length [1.6]–1.7 × that of anterior plate.

Eye: Short relative to breadth (1.4 × longer than broad), slightly convex on mesial margin, [reaching] or slightly falling short of apex of rostrum. Cornea not dilated, length [about half] or slightly more than half that of remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle 1.8–[2.1] × longer than high. Antennal peduncle overreaching cornea. Article 2 with distinct distolateral spine. Antennal scale relatively slender, 1.2–1.3 × broader than article 5, usually [terminating in], rarely barely reaching distal end of that article. Articles 4 and 5 each with distomesial spine; article 5 1.7–2.0 × longer than article 4, breadth 0.4 height of ultimate antennular article. Flagellum of 14 segments [reaching] or slightly overreaching distal end of P1 merus by distal 2 segments.

Mxp: Mxp1 with bases relatively close to each other but separated. Mxp3 unarmed on merus and carpus. Basis with [2] or 3 denticles on mesial ridge. Ischium with 28–[29] denticles on crista dentata, flexor margin not rounded distally. Merus 2.2–[2.6] × longer than ischium, relatively thick mesio-laterally, flexor margin moderately ridged.

P1: Massive (male palm massive, breadth subequal to distance between lateral orbital spines of carapace), distally with thick setae; length [3.8]–4.4 × (males), 4.5 × (female) that of carapace. Ischium with sharp dorsal spine and distinct ventromesial subterminal spine. Merus about as long as carapace, ventrally with tiny blunt distomesial and obsolescent distolateral spines, and several short granulate ridges and a few tubercles or small spines on ventro-proximal portion (in large specimens, several small spines along proximal part of lateral and mesial margins; in females, marginal spines very few or obsolescent). Carpus [about as long as] or very slightly shorter [rarely 1.2 × longer] than merus, somewhat depressed (height [0.8] or 0.9 × breadth]), ventrally smooth. Palm depressed (height [0.7] or 0.8 × breadth), [1.8] × (males), 2.0–2.4 × (females) longer than broad, [about as long as] or slightly shorter than (0.8 × in females) carpus, mesial margin smooth and roundly ridged, ventral surface polished. Fingers gaping in [proximal third] or proximal four-fifths in males (smaller P 1 in male, MCZ 2716, not gaping, presumably regenerated), not distinctly gaping in females, distally crossing with small wellincurved spine; movable finger 0.6–[0.7] × (0.96 × in smaller P 1 in male, MCZ 2716) as long as palm, opposable margin with [quadrangular and bicuspid] or low proximal process.

P2–4: Slender, sparsely setose but distal articles more setose. Meri successively shorter posteriorly (P3 merus 0.93–[0.95] × length of P2 merus, P4 merus 0.8 × length of P3 merus), breadths subequal on P2–4; length-breadth ratio [4.6]–4.9 on P2, 4.1–[4.7] on P3, [3.7]–4.1 on P4; dorsal and ventrolateral margins unarmed; P2 merus [about as long as] or 1.2 × longer (female, MCZ 2832) than carapace, [1.2]–1.3 × length of P2 propodus; P3 merus 1.0– [1.1] × length of P3 propodus; P4 merus [0.9] × length of P4 propodus. Carpi successively slightly shorter posteriorly or subequal on P2 and P3 and shorter on P4; carpus-propodus length ratio, 0.6 on P2, 0.5–0.6 [0.5] on P3, 0.5 on P4. Propodi subequal on P3 and P4, shorter on P2; flexor margin nearly straight, with pair of terminal spines preceded by row of 6–8 [7] basally articulated, long spines on P2, 5–8 [6] spines on P3, [5]–6 spines on P4. Dactyli subequal on P2–4, gently curving at proximal third, length 0.4 × that of propodus on P2–4; dactylus-carpus length ratio, 0.6–[0.7] on P2, 0.6–0.8 [0.7] on P3, 0.7–[0.8] on P4; flexor margin with 8–10 [9] (on P2 and P3), [8] (on P4) moderately obliquely directed, triangular spines, distal 4 or 5 subequal.

Color: Pink but lateral part of carapace and P2–4 pale, abdomen translucent ( Poupin & Corbari 2016: fig. 9f; Fig. 23 D, reproduced here by permission of Laure Corbari).

Distribution. Bahamas (Cay Sal Bank), Puerto Rico, Guadeloupe, off St. Vincent, Barbados, and Brazil (Pernambuco); 161– 453 m. Benedict (1901) recorded this species based on two lots taken by the U.S. F.C. Fish Hawk from Puerto Rico. One of these from Station 6070 was examined (see under Material). The other lot from Station 6065 could not be located. The latter material was recorded from an unusually shallow depth between 4–6 fms, which depth record remains questionable.

Remarks. This species was originally reported from Blake Stations 269, 273, 299 ( Milne-Edwards 1880). However, in the subsequent extensive account (Milne Edwards & Bouvier 1897), actual number and sex of specimens were given, with omission of Station 299. This omitted lot is now available registered under MCZ CRU- 2674. The three syntypes from the Blake Station 269 ( Milne-Edwards & Bouvier 1897: 141) each are now registered in three lots. Two of these (MCZ CRU-2590 and 4773) have not been examined. The syntype from Station 273 could not be located. Chace (1942: 20) wrote that part of the Blake specimens including syntypes of U. nitidus were referable to U. uncifer . Examination of these specimens disclosed that his identification was correct for the syntypes of U. uncifer and two lots of syntypes of U. nitidus from Blake Stations 232 (MCZ CRU-2832) and 297 (MCZ CRU-2713). However, the specimens from Blake Stations 147, 241, 254, 277 and 297, all syntypes of U. nitidus , proved to be a different species described above as U. reedae n. sp.

One of two lots taken at Blake Station 241 (ovigerous female, MCZ CRU-2582) is now very poor in condition. This lot contains two different chelipeds, one is typical of U. uncifer , bearing a distinct subterminal spine on the ischium, and the other is very much like that of U. reedae , lacking the spine. The antennae that help discriminate between U. uncifer and U. reedae are missing. This specimen is here treated as unidentifiable.

Figures

FIGURE 3. Uroptychus alphonsei n. sp., holotype, male (CL 5.3), MCZ CRU- 11320. A, carapace and anterior part of abdomen, dorsal; B, same lateral; C, sternal plastron, with excavated sternum, proximal part of Mxp 1 included. D, telson. E, right antenna, ventral. F, right Mxp 3, ventral, G, same, lateral. Scales = 1 mm.

FIGURE 20. Uroptychus uncifer (A. Milne-Edwards, 1880), lectotype, male (CL 4.1), MCZ CRU- 2674. A, carapace and anterior part of abdomen, dorsal. B, same, lateral. C, sternal plastron, with excavated sternum, proximal part of Mxp 1 included. D, telson. E, left antenna, ventral. F, left Mxp 3, ventral; G, same, lateral. Scales = 1 mm.

FIGURE 21. Uroptychus uncifer (A. Milne-Edwards, 1880), A – C, lectotype, male (CL 4.1), MCZ CRU- 2674; D – F, paralectotype, male (CL 5.3), MCZ CRU- 2716. A, left P 1, dorsal. B, same, mesial. C, same, proximal part (ischium and merus), ventral. D, left P 1, dorsal. E, same, proximal part (ischium and merus), dorsomesial. F, same, ventral. Scales = 1 mm.

FIGURE 22. Uroptychus uncifer (A. Milne-Edwards, 1880), lectotype, male (CL 4.1), MCZ CRU- 2674. A, right P 2, lateral. B, same, distal part, setae omitted, lateral. C, right P 3, setae omitted, lateral. D, same, distal part, lateral. E, right P 4, lateral. F, same, distal part, lateral. Scales = 1 mm.

FIGURE 23. A, Uroptychus nitidus with host corals taken in the northwestern Gulf of Mexico, 27 ° 4.8 ’ N, 92 ° 49.2 ’ W, 1145.9 m, remotely operated vehicle Deep Discoverer from R. V. Okeanos Explorer, photo courtesy of the U. S. National Oceanographic and Atmospheric Administration Office of Ocean Exploration and Research. B, U. fenneri n. sp., off Guadeloupe, KARUBENTHOS 2015 Sta. DW 4592, 214 – 201 m, MNHN-IU- 2013 - 19018. C, U. janiceae n. sp., off Guadeloupe, KARUBENTHOS 2015 Sta. CP 4618, 780 – 828 m, MNHN-IU- 2013 - 19095. D, U. uncifer, off Guadeloupe, KARUBENTHOS 2015 Sta. DW 4538, 338 – 320 m, MNHN-IU- 2013 - 18912 (Photo credits: B and C, Joseph Poupin; D, Laure Corbari).