Uroptychus nitidus ( 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 : 253-257

Uroptychus nitidus ( A. Milne-Edwards, 1880)

( Figs. 1 , 2 , 23A )

Diptychus nitidus A. Milne-Edwards, 1880: 62 (part).— Milne-Edwards & Bouvier 1897: 134 (part), pl. 11, figs. 21–22, pl. 12, figs. 10–16.

Uroptychus nitidus .— Henderson 1888: 174, pl. 21, figs. 6, 2a.—de Melo 1999: 168, fig. 102.

Uroptychus nitidus (typical form).— Chace 1942: 11, fig. 3.— Pequegnat & Pequegnat 1970: 161, fig. 5–15.

Uroptychus nitidus nitudus .—de Melo-Filho 1999: 384, fig. 1 (copy of Chace 1942: fig. 3).

Not Uroptychus nitidus var. A.— Chace, 1942: 14, fig. 4 [= U. fenneri n. sp.].

Not Uroptychus nitidus var. B.— Chace, 1942: 15, fig. 5 [= U. janiceae n. sp.].

Not Uroptychus nitidus var. C.— Chace, 1942: 17, fig. 6 [= U. alphonsei n. sp.].

Dubious identification:

Uroptychus nitidus .— Kensley 1977: 167, fig. 4.— Barnard 1950: 495, figs 92g –i.— Alcock & Anderson 1894: 173.— Anderson 1896: 101.

Type material. Lectotype: MCZ CRU- 2756 , female (CL 7.1), off Martinique, 14°31’55”N, 61°07’28”W, 472 fms [863 m], 7 Feb. 1879, Blake Sta. 200.

Paralectotypes: MCZ CRU- 2695, 2 females (CL 7.3, 8.6), off Martinique, 14°42’35”N, 61°13’15”W, 502 fms [918 m], 5 Feb. 1879, Blake Sta. 195 . MCZ CRU- 2700, 1 male (CL 9.5), off Guadeloupe, 16°15.405'N, 61°32.902'W, 734 fms [1342 m], 22 Jan. 1879, Blake Sta. 173 . MCZ CRU- 2747, 1 female (CL 3.3), off Dominica, 15°32’18’N, 61°32’00”W, 611 fms [1117 m], 24 Jan. 1879, Blake Sta. 175 . MCZ CRU-2831, 1 male (CL 4.9), 3 females (CL 3.0, 3.1, 4.2), northwest of Dry Tortugas, Florida, 25°33’0”N, 84°35’0”W, 539 fms [986 m], Dec. 1877 – Mar. 1878, Blake Sta. 44. MCZ CRU- 3072, 2 females (CL 3.4, 5.2), off St. Lucia, 13°58’37”N, 61°4’45”W, 422 fms [772 m], 16 Feb. 1879, Blake Sta. 222 . MCZ CRU-3073, 1 male (CL 5.3), 1 ov. female (CL 10.7), 1 female (CL 4.6), off Dominica, 15°18’12”N 61°26’32”W, 542 fms [991 m], 29 Jan. 1879, Blake Sta. 190 . MCZ CRU- 4770, 2 males (CL 8.2, 11.7), off St. Vincent, 13°10’10”N, 61°18’15”W, 573 fms [1048 m], 19 Feb. 1879, Blake Sta. 227 . MCZ CRU- 4771, 1 male (CL 11.0), off St. Vincent, 13°06'45"N, 61°06'55"W, 88 fms [161 m], 21 Feb. 1879, Blake Sta. 232.

Other material examined. USNM 309623, 1 female (CL 9.6), northern Gulf of Mexico, off Louisiana , 27°27’42” N, 89°45’30”W, 1420–1600 m, 0 7 Dec. 1984, LGL/ MMS NGoMBCS Sta. C 4, id. L.H. Pequegnat . USNM 1014166,1 female (CL 11.5), northern Gulf of Mexico, off Louisiana , 26°44’24”N, 93°18’36”W, 1372– 1454 m, 9 Apr. 1984, LGL/ MMS NGoMBCS Sta. W 4, Id. W.E. & L.H. Pequegnat . USNM 29168, 1 male (CL 6.8), northern Gulf of Mexico, off Mississippi Delta , 28°38’30”N, 87°02’W, commensal host Acanella eburnea (Pourtalès) , 420 fms (768 m), 13 March 1885, Albatross Sta. 2394 . USNM 136680, 6 males (CL 7.2–10.0), 6 ov. females (CL 8.6–10.0), 1 female (CL 5.1), Straits of Florida, 23°58’N, 82°54’W, 805–842 m, 18 June 1963 . USNM 136684, 7 males (CL 6.8–10.4), 3 ov. females (CL 9.3–11.2), 3 females (CL 4.5–10.0), Straits of Florida, 23°51’N, 81°02’W, 1107–1162 m, 16 Sept. 1964 . USNM 136685, 1 male (CL 9.8), 1 ov. female (CL 10.2), 1 female (CL 9.0), Straits of Florida, 23°50’N, 81°37’W, 1208–1241 m, 17 Sept 1964 . USNM 309622, 1 male (CL11.0), northern Gulf of Mexico continental slope, off Louisiana , 27°31’04”N, 89° 48’59”W, 1064 m, 15 Nov.1984, LGL/ MMS NGoMCS Sta. C 8 . USNM 1027022, 1 ov. female (CL 9.0), northern Gulf of Mexico, 27°29’27”N, 89°47’47”W, 1355–1362 m, 31 May 2000 , DGOMB Sta. C-4. USNM 136688, 1 female (CL 6.5), Straits of Florida, 23°59’N 82°09’W, 979–1027 m, 0 1 Dec. 1964 . TCWC 2-0425, 3 males (CL 8.6–11.6), northwestern Caribbean Sea off eastern Mexico, 18°57’N, 87°09’W, 1144 m, commensal host gorgonian, 7 Jul. 1970, Alaminos Sta. 70A10-9, id. L. Pequegnat . TCWC 2-0426, 1 ov. female (CL 12.0), southern Caribbean Sea off northern Columbia , 11°31.8’N, 73°45.1’W, 1144 m, 16–17 Jul. 1970, Alaminos Sta. 70A10-29, id. L. Pequegnat . TCWC 2- 6947, 1 ov. female (CL 13.0), southern Caribbean Sea off northern Venezuela, 12°39’N 69°44’W, 1345 m, commensal host Isididae , 19 Jul. 1970, Alaminos Sta. 70A10-42, id. W. Pequegnat . TCWC 2-6864, 1 female (CL 11.5), southwestern Gulf of Mexico, 24°28’N, 96°35’W, 600 fms [1097 m], 12 Apr. 1964 , Oregon Sta. 4813 (identified as Uroptychus sp. by Michele de St. Laurent ) . TCWC 2-8142 , ov. female (CL 14.5), southwestern Gulf of Mexico, 18°54'N, 94°58.8'W, 777–823 m, 14 Aug. 1969, Alaminos Sta. 69A11-27 ( Fig. 5-15 in Pequegnat & Pequegnat 1970).

Description. Carapace: [1.1] × longer than broad; greatest breadth 1.3–1.7 [1.5] × distance between anterolateral spines (smaller in small specimens). Dorsal surface nearly smooth, with pair of granulate epigastric ridges, moderately convex from side to side and anterior to posterior, with shallow depression between gastric and cardiac regions. Lateral margin weakly convexly divergent posteriorly, with fine granulations (or obscurely denticulate), and ridged along posterior third of length. Anterolateral spine directed slightly anterolaterally, overreaching acuminate lateral limit of orbit. Rostrum sharp, triangular, with interior angle of [17]–23°, curving dorsally or horizontally directed straight forward; dorsal surface flattish, length [1.3]–1.5 × breadth, 0.4–[0.5] × length of remaining carapace, breadth 0.5–[0.6] × (0.7–0.8 × in small specimens) that of carapace measured at posterior margin. Lateral limit of orbit angular and acuminate, not spiniform. Pterygostomian flap smooth on surface, anteriorly roundish with tiny spine.

Sternum: Excavated sternum anteriorly triangular and sharply pointed, with posteriorly diminishing ridge in midline. Sternal plastron [as long as] or slightly shorter than broad; lateral extremities slightly divergent posteriorly between sternites 4 and 6, subparallel between sternites 6 and 7. Sternite 3 moderately depressed, anterior margin deeply excavated with pair of submedian spines, anterolateral angle blunt, occasionally angular, anterolateral end with small spine. Sternite 4 anterolateral margin irregular, bearing small or moderate-sized anterior spine not reaching anterior end of sternite 3, followed by posterior diminishing processes or spines; length [1.3]–1.6 × that of posterolateral margin. Anterolateral margin of sternite 5 as long as posterolateral margin of sternite 4.

Abdomen: Smooth. Somite 1 without transverse ridge, weakly convex from anterior to posterior. Somite 2 tergite 2.3–2.5 [2.4] × broader than long, pleuron with lateral margin concavely divergent posteriorly, blunt on posterolateral terminus. Pleura of somites 3–5 posterolaterally blunt angular. Telson 0.5–[0.6] × as long as broad; posterior lobe 1.4–2.2 [1.5] × longer than anterior lobe (longer in small specimens), [emarginate] or feebly concave on posterior margin.

Eyes: [1.3]–1.6 × (1.2 × in smallest specimen) longer than broad, reaching point 0.6 of rostral length, mesial margin concave. Cornea slightly inflated, slightly longer than remaining peduncle.

Antennule and antenna: Ultimate article of antennule 2.8–3.5 [3.1] × longer than high (shorter in small specimens). Antennal peduncle overreaching eye. Article 2 with distinct distolateral spine. Antennal scale terminating in between midlength and [distal fourth] of article 5, breadth [1.3]–1.6 × that of article 5, 0.4 × height of ultimate antennular article. Articles 4 and 5 unarmed; article 5 [2.2]–2.5 × longer than article 4. Flagellum of [17]–22 segment usually not reaching, rarely terminating in distal end of P1 merus.

Mxp: Mxp1 with bases close to each other but not contiguous. Mxp3 basis with 3–[4] denticles on mesial ridge. Ischium with 18–26 [20] denticles on crista dentata, flexor margin not rounded distally. Merus [2.0]–2.3 × longer than ischium, flexor margin roundly ridged. No spine on merus and carpus.

P1: 4.7–5.4 × (males), 4.1–5.7 [5.5] × (females) longer than carapace (shorter in small specimens), nearly smooth and glabrous, but fingers setose. Ischium with small dorsal spine, ventromesially unarmed. Merus 1.1–1.5 [1.2] × longer than carapace; ventral surface with furrow mesial to lateral margin. Carpus [1.3] × longer than merus, dorsal surface with rounded longitudinal ridge in midline of anterior portion in large specimens, well depressed dorsoventrally, height much smaller than breadth (height-breadth ratio, 0.6–[0.7]). Palm 0.7–0.9 [0.8] × length of carpus, 2.6–3.0 × (males), 3.1–3.9 [3.5] × (females) longer than broad. Fingers not gaping, 0.5–[0.6] × length of palm, distally with small incurved spine; movable finger with bicuspid proximal process, fixed finger with low prominence (obsolescent in small specimens) distal to opposite process of movable finger.

P2–4: Slender, setose on distal 3 articles; Meri and carpi unarmed. Meri successively shorter posteriorly (P3 merus 0.8–[0.97] × length of P2 merus, P4 merus [0.8]–0.9 × length of P3 merus). P2 merus as long as or very slightly shorter than carapace, [1.2]–1.3 × longer than P2 propodus, P3 merus [1.1]–1.2 × length of P3 propodus, P4 merus [0.9]–1.0 × length of P4 propodus; length-breadth ratio, 6.5–7.6[7.2] on P2, 5.6–6.5 [6.6] on P3, 4.8–6.3 [5.8] on P4. Carpi successively shorter posteriorly, length 0.6 × that of propodus on P2, 0.6 × on P3, 0.5 × on P4. Propodi [subequal] or slightly longer on P4 than on P2 and P3; flexor margins straight, with pair of terminal spines preceded by 4–9 [7] basally articulated, long spines on P2 and P3, 4–7 [6] spines on P4 (fewer in small specimens). Dactyli subequal in length, curving at proximal fourth, length 0.4 × that of propodus, flexor margin with 10 or [11] (rarely 8 or 12) subtriangular, obliquely directed spines, distal 4 or 5 subequal, occasionally ultimate slightly longer.

Eggs: Number of eggs carried, ca. 20; size, 1.30 × 1.31 mm – 1.60 mm × 1.85 mm.

Color in life: Pale pink to dark orange ( Fig. 3 A).

Habitat: Symbiotic with gorgonians of families Chrysogorgiidae and Isididae growing on muddy sea floor ( Fig. 3 A). The only one of these gorgonians identified to species among the material we examined is Acanella eburnea (Pourtalès) ( USNM 29168). Pequegnat and Pequegnat (1970) reported that U. nitidus also associates with Chrysogorgia elegans (Verrill) (family Chrysogorgiidae ) and A. arbuscula (Johnson) . One of us (MKW) reexamined the specimen shown resting among the branches of C. elegans in their fig. 5-15, and confirmed that it is indeed U. nitidus ( TCWC 2-8142).

Remarks. The species is characterized by the rostrum usually distinctly upcurved distally (rarely feebly so); the epigastric region with a pair of granulate ridges behind eyes; the lateral orbital angle acuminate, not spiniform; the excavated sternum ridged in midline, without a spine in center; and the P1 carpus noticeably depressed dorsoventrally (0.6–0.7 as high as broad).

The ovigerous female (CL 10.7) of the specimens from Blake Sta. 190 (MCZ CRU-3073) seems to be aberrant in having a broader carapace (as long as broad), a broader and shorter rostrum (with the interior angle of 26°, 1.1 times longer than broad), shorter pereopods (P1 merus slightly shorter than carapace, P2 merus 0.7 times as long as carapace), broader P2–4 (length-breadth ratios of meri, 4.1, 3.6, 3.1 on P2, P3, P4 respectively). This specimen is provisionally placed in this species, awaiting a discovery of more material that allows molecular analyses.

The syntypes of U. nitidus from the Blake Stations 260 and 283, which were classified in variety A along with specimens from four Atlantis stations ( Chace 1942) , are referred to a new species named U. fenneri n. sp. (see below). The material from Station 130 registered under the syntype of U. nitidus (MCZ CRU-2734) proved to be identical with variety B of Chace, which is herein named U. janiceae n. sp. (see below). Chace (1942) noted that the Blake specimens from 147, 232, 241, 254, 269, 273, 277, 296, 297 and 299 were referable to U. uncifer . His identification was correct for those from Stations 232 and 297 (syntypes of U. nitidus ), and from Stations 269 and 299 (syntypes of U. uncifer ), but the other specimens from Stations 147, 241, 254, 277, all syntypes of U. nitidus , are referred to U. reedae n. sp. in this paper. The material from Station 273 could not be located. Distinguishing characters between U. nitidus and the other species are given under the respective species.

The identification of the Challenger material by Henderson (1888) was verified by direct examination.

Distribution. Straits of Florida, northern and southwestern Gulf of Mexico, north coast of Cuba, the Lesser Antilles from the Virgin Islands to St. Vincent (St. Croix, Culebra, Sombrero Islands, Guadeloupe, Dominica, Martinique, St. Lucia, St. Vincent),northwestern and southern Caribbean Sea, and Brazil (Pernambuco, Espírito Santo. Rio de Janeiro, São Paulo and Rio Grande do Sul); 161–1362 m.

Figures

FIGURE 1. Uroptychus nitidus (A. Milne-Edwards, 1880), lectotype, female (CL 7.1), MCZ CRU- 2756. 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 2. Uroptychus nitidus (A. Milne-Edwards, 1880), lectotype, female (CL 7.1), MCZ CRU- 2756. A, left P 1, proximal part, dorsal. B, same, ventral. C, same, distal part, dorsal. D, same, mesial. E, left P 2, lateral; F, same, distal part, setae omitted, lateral. G, left P 3, setae omitted, lateral. H, same, distal part, lateral. I, left P 4, lateral. J, same, distal part, lateral. Scales = 1 mm.

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 5. Uroptychus alphonsei n. sp., holotype, male (CL 5.3), MCZ CRU- 11320. A, left P 2, lateral. B, same, distal part, setae omitted, lateral. C, left P 3, setae omitted, lateral. D, same, distal part, lateral. E, left P 4, lateral. F, same distal part, lateral. Scales = 1 mm.

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 9. Uroptychus janiceae n. sp., holotype, male (CL 6.8), MCZ CRU- 11318. 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, right Mxp 3, ventral; G, same, lateral. Scales = 1 mm.

FIGURE 10. Uroptychus janiceae n. sp., holotype, male (CL 6.8), MCZ CRU- 11318, A – C, left P 1. D, E, right 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 11. Uroptychus janiceae n. sp., holotype, male (CL 6.8), MCZ CRU- 11318. A, left P 2, lateral. B, same, distal part, setae omitted, lateral. C, left P 3, setae omitted, lateral. D, same, distal part, lateral. E, left P 4, lateral. F, same, distal part, lateral. Scales = 1 mm.

FIGURE 12. Uroptychus lindae n. sp., holotype, male (CL 5.5), USNM 1254678. 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 13. Uroptychus lindae n. sp., holotype, male (CL 5.5), USNM 1254678, left P 1. A, ischium, merus and carpus. B, palm and fingers. C, ischium and merus, ventral. D, same, lateral. E, merus and carpus, mesial. F, palm and fingers, mesial. Scale = 1 mm.

FIGURE 14. Uroptychus lindae n. sp., holotype, male (CL 5.5), USNM 1254678. A, left P 2, lateral. B, same, distal part, setae omitted, lateral. C, left P 3, setae omitted, lateral. D, same, distal part, lateral. E, left P 4, lateral. F, same, distal part, lateral. Scales = 1 mm.

FIGURE 15. Uroptychus rafai n. sp., male (CL 8.3), holotype, USNM 1107844. 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, right Mxp 3, ventral. 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).