Uroptychus lindae, 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 : 270-274

Uroptychus lindae n. sp.

( Figs. 12–14 )

Type material. Holotype: USNM 1254678 , male (CL 5.5), Caribbean Sea , off northern Columbia, 12°14.3’N, 72°31.8’W, 205 m, 18 July 1970, Alaminos Sta. 70A10-39.

Paratypes: TCWC 2-6946, 9 males (CL 2.0–4.7), 9 ov. females (CL 4.3–5.6), 6 females (CL 2.5–5.9); TCWC 2-6948, 3 ov. females (CL 4.1–4.3), station data as for holotype .

Description. Carapace: 1.0–[1.1] × longer than broad; greatest breadth [1.6]–1.7 × distance between anterolateral spines. Dorsal surface smooth, glabrous and unarmed, with distinct depression between convex gastric and cardiac regions. Lateral margins smooth, somewhat divergent posteriorly, convex along branchial region, distinctly ridged along posterior third. Anterolateral spine well developed, directly (very closely) lateral to and overreaching lateral limit of orbit, directed straight forward. Rostrum 1.2–[1.4] × (rarely 1.1) longer than broad, narrow triangular with interior angle of 13–18 [16]°, straight horizontal or [directed slightly ventrally]; length about half that of remaining carapace, breadth slightly more than half that of carapace measured at posterior margin; dorsal surface concave; lateral margins straight on distal two-thirds, concave on proximal third. Lateral limit of orbit rounded or with very tiny spine. Pterygostomian flap anteriorly somewhat roundish, produced to small spine.

Sternum: Excavated sternum sharply produced anteriorly, surface with small spine in center. Sternal plastron 0.9–[1.0] × as long as broad, lateral extremities between sternites 4 and 7 weakly divergent posteriorly. Sternite 3 well depressed, with deeply excavated anterior margin bearing 2 distinct submedian spines separated by notch, laterally angular, anterolateral end with distinct spine. Sternite 4 anterolateral margin 1.7–[2.0] × longer than posterolateral margin, anteriorly ending in spine not reaching anterior end of sternite 3, followed by distinct or obsolescent posteriorly diminishing spines. Anterolateral margin of sternite 5 [1.5]–1.6 × longer than posterolateral margin of sternite 4.

Abdomen: Tergites smooth and glabrous. Somite 1 gently convex from anterior to posterior, not transversely ridged. Somite 2 tergite 2.2–2.7 [2.4]× broader than long; pleuron posterolaterally ending in rounded terminus, lateral margins slightly concavely divergent posteriorly. Pleura of somites 3 and 4 laterally rounded. Telson 0.6 × as long as broad; posterior plate moderately, [slightly] or barely concave on posterior margin, length [1.5]–1.7 × that of anterior plate.

Eye: Short relative to breadth (1.6–[1.7] × as long as broad), ending in [distal third] to distal two-fifths length of rostrum, lateral margin strongly convex, especially in small specimens. Cornea not dilated, distinctly narrower than and [0.6]–0.7 × as long as remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle 2.6–[3.5] × longer than high. Antennal peduncle slightly overreaching cornea. Article 2 with distinct distolateral spine. Antennal scale slender, narrower than article 5, reaching [distal end] or midlength of second segment of flagellum, rarely slightly overreaching first segment. Article 4 [unarmed] or with tiny or obsolescent distomesial spine. Article 5 1.5–[1.7] × longer than article 4, breadth slightly more than half height of ultimate antennular article, distomesially with distinct spine. Flagellum of 15–18 [18] segments overreaching distal end of P1 merus by distal 1–[5] segments.

Mxp: Mxp1 with bases relatively close to each other but separated. Mxp3 spineless on merus and carpus. Basis with [1]–3 denticles on mesial ridge. Ischium with [22]–23 denticles on crista dentata, flexor margin not rounded distally. Merus 2.4 × longer than ischium, relatively thick mesio-laterally, flexor margin roundly ridged.

P1: Sparsely setose but fingers with thick setae; length [5.4]–6.1 × (males), 5.8–6.1 × (females) that of carapace. Ischium with sharp dorsal spine and small additional spine distantly proximal to it, unarmed along ventromesial margin. Merus [1.2]–1.3 × longer than carapace, ventrally with tiny blunt distomesial and distolateral spines and scattered tubercles on proximal half. Carpus [1.4]–1.5 × longer than merus, subcylindrical, ventrally with small blunt distomesial and distolateral spines, with [distinct] or obsolescent tubercles on ventral distal portion. Palm somewhat depressed (height [0.8]–0.9 × breadth), [2.9]–3.7 × (males), 4.3–4.8 × (females) longer than broad, 0.8–[1.0] × length of carpus, mesial margin roundly ridged, ventral surface polished. Fingers [gaping in proximal half] or not gaping, distally slightly crossing; movable finger [0.5]–0.6 × as long as palm, opposable margin with bluntly triangular process on gaping margin.

P2–4: Slender, with long setae. Meri successively shorter posteriorly (P3 merus 0.8–[0.9] × length of P2 merus, P4 merus [0.8]–0.9 × length of P3 merus); length-breadth ratio 6.5–[6.6] on P2, 5.0–5.6 [5.1] on P3, 4.6 on P4; dorsal and ventrolateral margins unarmed; P2 merus [1.0]–1.1 × length of carapace, 1.3–[1.5] × length of P2 propodus; P3 merus 1.0–1.3 [1.2] × length of P3 propodus; P4 merus [0.9]–1.0 × length of P4 propodus. Carpi subequal on P2–4; carpus-propodus length ratio, 0.6 on P2 and P3, [0.5]–0.6 on P4. Propodi successively longer posteriorly; flexor margin nearly straight, with pair of terminal spines preceded by row of 7–[8] basally articulated, relatively closely arranged, long spines on P2, 6–[8] spines on P3, 6–[7] spines on P4. Dactyli subequal on P2–4, moderately curving at proximal fourth, length 0.4 × that of propodus on P2, P3, P4 respectively; dactylus-carpus length ratio, 0.6 on P2 and P3, 0.7 on P4; flexor margin with 9–[11] (P2), 9–[11] (P3), 10–[11] (P4) somewhat obliquely directed, subtriangular spines, distal 5 or 6 subequal or very slightly diminishing proximally.

Eggs: Number of eggs carried, up to 12; size, 0.90 × 1.00 mm– 1.16 mm × 1.40 mm.

Habitat. Symbiotic with unidentified Chrysogorgia sp. The original label identified the gorgonian as C. elegans , but Les Watling (University of Hawaii at Manoa, pers. comm.) examined a specimen and believes that it is an undescribed species.

Remarks. The smallest male (CL 2.0), which lacks P1 and P2, looks immature, showing the following features that are different from the other larger specimens: rostrum broad triangular with interior angle of 28°, 0.8 as long as broad, terminating in distal end of eye; eyes short relative to breadth (length 1.4 × breadth), with strongly inflated eyestalk; antennal flagellum consisting of 12 segments; P2–4 propodi and dactyli with fewer spines (propodi with 5 and 4 flexor marginal spines proximal to the distal pair on P3 and P4 respectively, and dactyli with 6 flexor marginal spines).

The new species is readily distinguished from the other related species by the combination of the following characters: the anterolateral spine very close to the lateral limit of orbit, the antennal scale exceeding beyond article 5, and article 5 with a distinct distomesial spine.

Distribution. Caribbean Sea off northern Columbia, 205 m.

Etymology. Dedicated to Linda H. Pequegnat for her contribution to the knowledge of western Atlantic squat lobsters. This species was first recognized by her as distinct from U. nitidus , giving the name Uroptychus sp. D.

Figures

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.