Uroptychus fenneri, Baba, Keiji & Wicksten, Mary K., 2017

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 : 261-264

Uroptychus fenneri n. sp.

( Figs. 6–8 , 23 B)

Uroptychus nitidus . — A. Milne-Edwards, 1880: 62 (part).

Uroptychus nitidus var. A.— Chace, 1942: 14, fig. 4.— Poupin & Corbari 2016: 36, fig. 9b.

Type material. Holotype: MCZ CRU- 2715 , male (CL 5.0), off Grenada, 2°3'30"N, 61°47'10"W, 291 fms [532 m], 28 Feb. 1879, Blake Sta. 260.

Paratypes: MCZ CRU- 2724, 2 males (4.1, 4.3), off Barbados, 13°5’5”N, 59°40’50”W, 236 fms [432 m], 7 Mar. 1879, Blake Sta. 283 . USNM 1107841, 1 male (CL 5.3), USNM 1000760, 74 males (CL 3.7–5.4), 31 ov. females (CL 4.0–5.0), 45 females (CL 3.0–5.0), northeastern Gulf of Mexico , Florida, SW of Panama City, 28°07’38”N, 85°51’36”W, 624–631 m, 16 May 1985 . USNM 250195, 2 males (CL 5.0, 5.6), 9 ov. females (CL 4.0–5.0), 1 female (CL 2.8), northeastern Gulf of Mexico, off Tampa , Florida, 370 fms [677 m], 6 May 1987 . USNM 155631, 1 ov. female (CL 5.5), Straits of Florida, off Little Bahama Bank, 700 m, 11 Nov. 1974 . USNM 1027031, 1 male (CL 4.6), northern Gulf of Mexico, De Soto Canyon, DGoMB Sta. S 35, 29°22’33”N, 87°01’46”W, 645–695 m, 12 June 2000 . USNM 92630, 3 males (CL 3.0–4.7), 3 ov. females (CL 4.3–4.7), northeastern Gulf of Mexico , Oregon Sta. 489, 27°44’N, 85°09’W, 254 fms [465 m], 29 Sept. 1951, U.S. Fish & Wildlife Service. USNM 1000632, 20 males (CL 4.2–5.3), 3 ov. females (CL 4.5–5.7) , 13 females (CL 3.4–5.1), Florida , Panama City, 28°35’01”N, 86°45’44”W, 625 m, 13 May 1985 . USNM 1107847, 1 male (CL 5.5), Oregon II Sta. 11717, 30°52’N, 79°34’W, 360 fms [658 m], 21 Jan. 1972 . TCWCX 2-6781 : 14 bodies, southwestern Gulf of Mexico, off eastern Mexico, 21°16.2'N, 96°51.8'W, 567 m, 7 Aug. 1971, Alaminos Sta. 71A8-40, id. L. Pequegnat.

Description. Carapace: [1.1]–1.2 × longer than broad; greatest breadth 1.5 × distance between anterolateral spines. Dorsal surface smooth, moderately convex from side to side, feebly so from anterior to posterior, [with] or without feeble depression between gastric and cardiac regions. Gastric region with pair of [granulate ridges]or very small spines behind eyes. Lateral margins somewhat convex posteriorly, nearly smooth, ridged along posterior third. Anterolateral spine relatively small, directed straight forward or [slightly anterolaterally], usually terminating in tip of small lateral orbital spine and located anterior to position of that spine. Rostrum narrow triangular, with interior angle of 14–[21°], straight horizontal; lateral margins [slightly convex] or straight in distal two-thirds, concave in proximal third; dorsal surface flattish; length 1.3–[1.6] × breadth, 0.5–[0.7] length of carapace. Pterygostomian flap smooth on surface, anteriorly roundish, with small spine.

Sternum: Excavated sternum anteriorly produced to small spine between close bases of Mxp1, surface with small spine in center. Sternal plastron as long as broad, lateral extremities of sternites 4–7 weakly divergent posteriorly. Sternite 3 well depressed, anterior margin semicircularly excavated with pair of submedian spines separated by narrow notch. Sternite 4 anterolateral margin irregular, with posteriorly diminishing spines, anteriormost not reaching anterior end of sternite 3; length 1.3–1.7 [1.5] × that of posterolateral margin. Sternite 5 with anterolateral margin convexly divergent posteriorly, about as long as posterolateral margin of sternite 4.

Abdomen: Smooth and glabrous. Somite 1 weakly convex from anterior to posterior, without ridge. Somite 2 tergite 2.2–2.5 [2.4] × broader than long, pleuron rounded on anterolateral margin. Pleura of somites 3–5 laterally blunt. Telson 0.6 × as long as broad, posterior lobe [1.6]–2.0 × longer than anterior lobe, [distinctly] or weakly emarginate on posterior margin (occasionally not emarginate in small specimens).

Eyes: Terminating in between [midlength] and point two-thirds of rostral length, mesial and lateral margins weakly convex. Cornea not dilated, slightly shorter than remaining eyestalk.

Antennule and antenna: Ultimate article of antennule 1.8–2.2 [2.0] × longer than broad. Antennal peduncles relatively slender, reaching or slightly overreaching eye. Article 2 with distinct short distolateral spine. Antennal scale slender, 1.3–[1.4] × broader than article 5, slightly overreaching article 5 (often [reaching] or overreaching distal end of proximal second segment of flagellum). Articles 4 and 5 unarmed; article 5 2.3–[2.6] × longer than article 4, breadth [0.3]–0.4 × height of ultimate article of antennule. Flagellum consisting of 10–[15] segments, not reaching end of P1 merus.

Mxp: Mxp1 with bases close to each other but not contiguous. Mxp3 basis with [2]–5 denticles on mesial ridge. Ischium with 17–[22] denticles on crista dentata, flexor margin not rounded distally. Merus [2.4]–2.5 × longer than ischium, spineless, flexor margin roundly ridged. Carpus unarmed.

P1: [5.0]–5.3 × (males), 5.6–6.0 × (females) longer than carapace, nearly glabrous except for fingers, generally smooth. Ischium with small dorsal spine, unarmed elsewhere. Merus 1.2–1.4 [1.3] × as long as carapace, ventromesial margin with row of obtuse small processes or granules, occasionally with another paralleling row of similar processes mesial to it. Carpus subcylindrical, length 1.2–1.5 [1.3] × that of merus. Palm 0.7–1.0 [0.8] × length of carpus, 3.0–3.9 [3.3] × (males), 3.9–5.2 × (females) as long as broad, [0.7] as high as broad. Fingers gaping in males, not gaping in females, tips slightly incurved; when closed, opposable margins straight in distal third or [distal half] in males, in entire length in females; in males, movable finger with [truncate] (often obscurely bicuspid) process at midlength of gaped margin; in females, with low proximal process; length about half ([0.45]– 0.57) that of palm.

P2–4: Moderately compressed, sparsely setose, unarmed on meri and carpi. Meri successively shorter posteriorly (P3 merus 0.8–[0.9] × length of P2 merus, P4 merus 0.7–[0.8] × length of P3 merus); length-breadth ratio, 4.9–5.9 [5.5] on P2, 4.4–5.2 [4.6] on P3, 3.8–4.3 [3.9] on P4. P2 merus as long as or slightly [0.9] shorter than carapace, [1.3] (rarely 1.2) × longer than P2 propodus; P3 merus 1.1 × length of P3 propodus, P4 merus 0.9 × length of P4 propodus. Carpi successively shorter posteriorly, length [0.6] × (rarely 0.7) that of propodus on P2–3, 0.5 × on P4. Propodi subequal on [P2–4], shorter on P4 than on P2–3 or successively shorter posteriorly; flexor margin with 7–10 [9] basally articulated, long spines on P2, 7–[9] on P3, 6–[8] on P4, terminal spine single, situated very near end of margin. Dactyli subequal on P2–4 or [slightly longer on P3 and P4], slightly less than half (0.4) length of propodus, distinctly curving at proximal third; flexor margins with 8–10 [8 or 9] subtriangular, proximally diminishing, strongly obliquely directed spines, ultimate spine slightly larger than penultimate.

Color: Overall pale pink, with very narrow orange stripe in midline of rostrum, behind each eye straightly extending posteriorly to between gastric and branchial regions, and along upper margin of pterygostomian flap; antennal flagellum orange ( Poupin & Corbari 2016: fig. 9b; Fig. 23 B, reproduced by permission of J. Poupin).

Remarks. This species is referable to U. nitidus var. A of Chace (1942).

Uroptychus fenneri n. sp. is easily distinguished from U. nitidus by the antennal scale, which extends beyond instead of falling short of the distal end of article 5, the P1 carpus, which is subcylindrical instead of strongly flattened, and the P2–4 propodi, which bear the distalmost of flexor marginal spines single instead of being paired.

This species shares with U. rafai n. sp. the distalmost of the flexor marginal spines single, not paired on the P2–4 propodi. Distinguishing characters between these two species are outlined under U. rafai (see below).

The material from the following Atlantis stations ( Chace 1942) is now housed in the collection of the Museum of Comparative Zoology under registration numbers indicated in parentheses: Stations 3459 (MCZ CRU-11315), 3469 (MCZ CRU-11304), 3476 (MCZ CRU-11311) and 3782 (MCZ CRU-11314).

Distribution. Off east coast of Florida (off St. Augustine), northeastern and southwestern Gulf of Mexico, north coast of Cuba, Guadeloupe, Barbados, Grenada and off northern Columbia; 201– 914 m.

Etymology. Dedicated to the late Fenner A. Chace, Jr. for his works on squat lobsters of the western Atlantic. KB thanks his help and support during a stay in the Smithsonian during 1974–75 and for his welcome manner to review manuscripts on request.

Figures

FIGURE 6. Uroptychus fenneri n. sp., holotype, male (CL 5.0), MCZ CRU- 2715. 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 7. Uroptychus fenneri n. sp., holotype, male (CL 5.0), MCZ CRU- 2715, left P 1. A, ischium, merus and carpus, dorsal. B, palm and fingers dorsal. C, ischium and merus, ventral. D, carpus, mesial. E, palm and fingers, mesial. Scale = 1 mm.

FIGURE 8. Uroptychus fenneri n. sp., holotype, male (CL 5.0), MCZ CRU- 2715. 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).