Uroptychus alphonsei, 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 : 257-261

Uroptychus alphonsei n. sp.

( Figs. 3–5 )

Uroptychus nitidus var. C.— Chace, 1942: 17, fig. 6.

Type material. Holotype: MCZ CRU- 11320 , male (CL 7.9), off Caibarién , Santa Clara Province, north coast of Cuba, 22°52’30”N, 79°22’W, 240 fms [439 m], 1 May 1939, Atlantis Sta. 3428.

Paratype: MCZ IZ 49766, 1 ov. female (CL 9.9), collected with holotype.

Description. Carapace: Slightly (1.1 ×) longer than broad; greatest breadth 1.6 × distance between anterolateral spines. Dorsal surface smooth, glabrous and unarmed, somewhat inflated in profile, with moderate depression between gastric and cardiac regions. Lateral margins slightly convexly divergent posteriorly, with 5 or 6 very small spines along anterior half of posterior branchial margin; feebly ridged near posterior end. Anterolateral spine small, slightly larger than lateral orbital spine, situated distinctly posterior to position of and not reaching tip of that spine, directed anterolaterally. Rostrum [1.2]–1.3 × longer than broad, narrow triangular with interior angle of 15°, straight horizontal; length slightly less than half that of remaining carapace, breadth about half that of carapace measured at posterior margin; lateral margins concave on proximal third; dorsal surface flattish. Pterygostomian flap anteriorly somewhat roundish, produced to small spine.

Sternum: Excavated sternum sharply produced anteriorly, surface with small spine in center. Sternal plastron about as long as or [very slightly longer] than broad, lateral extremities weakly divergent posteriorly between sternites 4–6, subparallel between sternites 6 ad 7. Sternite 3 well depressed, with deeply excavated anterior margin bearing 2 distinct submedian spines separated by notch, laterally angular, anterolateral end with distinct low spine. Sternite 4 anterolateral margin irregular, anteriorly ending in [strong] or short stout spine not reaching anterior end of sternite 3, length 1.5 × that of posterolateral margin. Anterolateral margins of sternite 5 slightly 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 2.2 × broader than long; pleuron with rounded posterolateral terminus, lateral margins somewhat concavely divergent posteriorly. Pleura of somites 3 and 4 laterally rounded. Telson slightly more than half as long as broad; posterior plate [somewhat concave] or distinctly emarginate on posterior margin, length 1.9 × that of anterior plate.

Eye: [1.8]–1.9 × longer than broad; lateral and mesial margins subparallel, ending in distal third length of rostrum. Cornea not dilated, slightly shorter than remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle [2.9]–3.3 × longer than high. Antennal peduncle overreaching cornea. Article 2 with distinct distolateral spine. Antennal scale slender, as broad as article 5, very slightly falling short of distal end of that article. Distal 2 articles unarmed; article 5 [2.0]–2.3 × longer than article 4, breadth about half height of ultimate antennular article. Flagellum of 20–21 segments reaching distal end of P1 merus.

Mxp: Mxp1 with bases relatively close to each other, not contiguous. Mxp3 spineless on merus and carpus. Basis with 3 denticles on mesial ridge. Ischium with 27–[30] denticles on crista dentata, flexor margin not rounded distally. Merus 2.3 × longer than ischium, relatively thick mesio-laterally, flexor margin moderately ridged.

P1: Sparsely setose but fingers with thick setae, ventrally somewhat granulose on ischium, merus and carpus; length 5.2 × (male), 5.0 × (female) that of carapace. Ischium with sharp dorsal spine, unarmed along ventromesial margin. Merus 1.1–[1.2] × longer than carapace, ventrally with tiny blunt distomesial and distolateral spines. Carpus [1.2]–1.3 × longer than merus, subcylindrical, ventrally with small blunt distomesial and distolateral spines. Palm depressed (height 0.6 × breadth), [2.2] × (male), 3.3 × (female) longer than broad, 0.9 × length of carpus, mesial margin moderately ridged, with very small serration in distal half in male, smooth in female, ventral surface polished. Fingers gaping in proximal half in male, weakly so in proximal third in female, distally with no distinct spine; movable finger 0.6–0.7 × as long as palm, opposable margin with bluntly triangular process on gaping margin in male, bicuspid process in female.

P2–4: Slender, with long setae. Meri successively shorter posteriorly (P3 merus [0.94]–0.97 × length of P2 merus, P4 merus 0.8–[0.9] × length of P3 merus); length-breadth ratio [6.6]–7.2 on P2, [6.3]–6.8 on P3, [5.5]–6.1 on P4; dorsal and ventrolateral margins unarmed; P2 merus 1.0–[1.1] × length of carapace, 1.3 × length of P2 propodus; P3 merus 1.2 × length of P3 propodus; P4 merus [0.95]–1.0 × length of P4 propodus. Carpi subequal on P2–4; carpus-propodus length ratio, [0.6] on P2, [0.5]–0.6 on P3, 0.5 on P4. Propodi successively longer posteriorly; flexor margin nearly straight, with pair of terminal spines preceded by row of [8] or 9 basally articulated, long spines on P2, 10 spines on P3, [8] or 9 spines on P4. Dactyli subequal on P2–4, moderately curving at proximal third, length 0.4 × length of propodus on P2–4; dactylus-carpus length ratio, 0.7 on P2–4; flexor margin with 10 or 11 somewhat obliquely directed, triangular spines, distal 5 or 6 subequal.

Eggs: Number of eggs carried, 20; size, 1.00 × 1.22–1.10 × 1.15 mm.

Remarks. One (ovigerous female, Atlantis Sta. 2999 ) of the specimens reported by Chace (1942) could not be located. Very possibly it may have been sent to either the Museo Poey (Museo de Historia Natural Felipe Poey), Havana or the Bermuda Aquarium ( Bermuda Aquarium, Museum & Zoo), Flatts (see Chace 1942: 2).

Chace (1942) noted that U. nitidus var. C (= U. alphonsei n. sp.) is distinguished from U. nitidus var. B (= U. janiceae n. sp.) by pale eyes and rougher P1 with shorter fingers. This can be complemented by the following additional differences: the anterolateral spine of the carapace falls short of instead of overreaching the tip of the lateral orbital spine; the carapace lateral margin is more distinctly spinose rather than obscurely denticulate; the crista dentata bears more numerous denticles, 27–30 versus 17–21; the antennal scale is more slender, being equally broad as instead of 1.5–2.0 times broader than article 5; and the anterior margin of sternite 3 is more deeply excavated.

Uroptychus nitidus , from which Chace (1942) first separated this species by naming variety C, is distinctive in the P1 carpus, which is flattened instead of subcylindrical, in having a pair of epigastric ridges, in having the carapace lateral margin obscurely denticulate, and in having the lateral limit of the orbit angular, not spiniform.

Distribution. North coast of Cuba; 265– 439 m.

Etymology. Named for Alphonse Milne-Edwards who contributed much to the knowledge of squat lobster taxonomy, especially by his papers on the collections made by the U.S. Coast Survey Steamer Blake in the Gulf of Mexico (1877–78), in the Caribbean Sea (1878–79) and along the Atlantic coast of the United States (1880), and by the R/V Travailleur and the Talisman in the Canary and Cape Verde Islands and in the Azores (1880–1883).

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 4. Uroptychus alphonsei n. sp., holotype, male (CL 5.3), MCZ CRU- 11320, right P 1. A, ischium, merus and carpus, ventral. B, same, dorsal. C, palm and fingers, dorsal. D, ischium, merus and carpus, mesial. E, palm and fingers, mesial. Scale = 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.