Leptochela papulata Chace 1976

Leptochela (Leptochela) papulata

DIAGNOSIS.—Rostrum with dorsal margin convex or slightly sinuous. Carapace with 3 longitudinal dorsal ridges in breeding females only. Orbital margin entire, rarely minutely serrate, without mesially directed tooth on ventral portion; suborbital angle unarmed. Fifth abdominal somite with 1 to 3 more or less distinct pimplelike elevations in posterior half of dorsal midline, without posterior tooth. Telson with 1 pair of dorsolateral spines in addition to anterior mesial pair; posterior margin with pair of minute mesial spines in addition to usual 5 pairs of prominent spines. Antennal scale barely ½ as long as carapace. First pereopod with 16 to 28 spines on opposable margin of movable finger. Second preopod with 22 to 36 spines on opposable margin of movable finger. Third pereopod with exopod not nearly reaching distal end of ischium. Endopod of 1st pleopod of male flared distolaterally. Appendix masculina, not including spines, distinctly overreaching appendix interna. Maximum carapace length 4.4 mm.

DESCRIPTION.—Rostrum (Figure 22a) usually with dorsal margin regularly convex, rarely slightly concave in anterior half, usually falling short of distal surface of eye, rarely overreaching basal segment of antennular peduncle. Carapace with median dorsal carina on anterior 1/5 to ½ length in males and nonbreeding females, sharply tricarinate over most of length in breeding females. Orbital margin (Figure 22b) entire, rarely minutely serrate, ventral portion without mesially directed tooth; suborbital angle rounded, not dentate.

Abdomen (Figure 22c) regularly rounded dorsally on 4 anterior somites. Fifth somite (Figure 22c,g) bluntly carinate dorsally, carina usually surmounted in posterior half by 1 to 3 (usually 3) pimplelike elevations, rarely with barely visible vestiges thereof; posterior margin unarmed. Sixth somite about 1.6 times as long as high, with usual transverse swelling and carina near anterior end of dorsal surface, long slender spine on ventrolateral surface, and usually with minute blunt tooth (Figure 22d) on posterodorsal margin of posterolateral lobe (tooth sometime lacking, rarely prominent and acute). Telson (Figure 23a), not including posterior spines, about 1.8 times as long as 6th somite, about 3.4 times as long as wide, armed with 1 pair of dorsolateral spines at about midlength, in addition to anterior mesial pair; posterior margin (Figure 23b) bearing pair of minute spines (Figure 23c) between bases of mesial pair of usual 5 pairs of prominent spines.

Eye (Figure 22b) with papilla on mesial surface of stalk proximal to cornea, cornea slightly wider than stalk.

Antennular peduncle (Figure 22e) with stylocertie reaching nearly as far as distolateral margin of basal segment; 2nd segment longer than distal segment in mesial aspect but distinctly shorter in dorsal aspect.

Antennal scale (Figure 22f) barely 0.5 as long as carapace, 2.8 to 3.5 times as long as wide, lateral margin sinuous, blade forming rather distinct shoulder at base of distal tooth. Distal segments of antennal peduncle about 2/3 as wide as scale and nearly reaching midlength of scale.

Mouthparts as illustrated (Figure 23d–i). Third maxilliped (Figure 23i) rarely overreaching antennal scale, distal segment about 4/5 as long as penultimate segment.

First pereopod (Figure 23j) usually overreaching antennal scale by little more than length of fingers; fingers 1.2 to 1.5 times as long as palm; dactyl (Figure 23k) armed with 16 to 28 spines on opposable margin. Second pereopod (Figure 23l) sometimes overreaching antennal scale by more than length of fingers; fingers 1.6 to 2.0 times as long as palm; dactyl (Figure 23m) armed with 22 to 36 spines on opposable margin. Third pereopod (Figure 23n) overreaching extreme anterior margin of carapace by about length of dactyl; exopod falling far short of distal end of ischium; ischium armed with row of about 9 slender sharp spines near extensor margin and 3 subequally spaced stout spines on lateral surface; merus with 4 longer blunt spines on lateral surface; dactyl slightly shorter than propodus. Fourth pereopod (Figure 23o) overreaching ischium of 2nd pereopod by about length of dactyl when both extended anteriorly; dactyl shorter than propodus. Fifth pereopod (Figure 23p) similar to and only slightly shorter than 4th, reaching to about distal 1/3 of ischium of 2nd pereopod when both extended anteriorly; dactyl nearly as long as propodus.

Endopod of 1st pleopod of male (Figure 24a,6) with lateral margin flared distally. Appendix masculina (Figure 24c,d) bearing 7 long spines, distinctly overreaching appendix interna, without including spines. Lateral branch of uropod (Figure 23a) armed with 10 to 17 movable spines, in addition to setae.

SIZE.—Carapace lengths of males, 2.1–3.9 mm; of nonbreeding females, 2.2–3.6 mm; of nonovigerous breeding females, 2.7, 3.9 mm; of ovigerous females, 3.2–4.4 mm; of juveniles, 1.6–2.0 mm. The smallest male has a barely discernible appendix masculina; the smallest male with a fully developed appendix masculina has a carapace length of 2.6 mm.

Material.—NORTH CAROLINA. East of Cape Lookout; 34°35′30″N, 75°45′30″W; 59 m; white sand with black specks; 18 October 1885; large beam trawl; Albatross Sta. 2605: 1 ovig. (3.8) holotype. Southeast of Cape Lookout; 34°34.5′N, 76°25.5′W; 20 m; sand and broken shell; 9°C; 19 January 1966; dredge; Beveridge (J. H. Day Sta. BST. 271. V.): 1 (2.6) 1 (2.5). Same locality and date; 0.2m2 Van Veen grab; Beveridge (J. H. Day Sta. BST 274. E.): l (2.2). 34°28.5′N, 76°13.1′W; 33 m; 15 February 1965; Van Veen grab; Eastward Sta. 489: 1 juv. (2.0). 34°28.1′N, 76°20.0′W; 27 m; 15 February 1965; small biological trawl; Eastward Sta. 497: l (2.7) 1 juv. (2.0). 34°24.8′N, 75°59.5′W; 40 m; coarse sand and mud; 20.6° C; 30 November 1965; dredge; Eastward Sta. 3464 (J. H. Day Sta. BST. 236. P.): 1y (2.1). 34°20.0′W, 75°54.5′W; 202 m; hard packed; 8 January 1966; dredge; Eastward Sta. 3538 (J. H. Day Sta. BST. 289, M.): 1 juv. (1.6+). South of Cape Lookout; 34°04.5′N, 75°25.5′W; 20 m; coarse sand; 20°C; 24 November 1965; 0.2m2 Van Veen grab; Beveridge (J. H. Day Sta. BST. 233. N.): 1 ovig. (3.5).

SOUTH CAROLINA. Southeast of Charleston; 32°12′N, 79°15′W; 46 m; terigenous sand, shell debris; 12 July 1961 (1730-1732); Van Veen grab: Atlantis Sta. A–266–36: 1 (2.7).

GEORGIA. Sapelo Whistle 335°–5½ km; 21 m; 28 February 1962; M. Gray: I (3.6). East of Doboy Sound Sea Buoy 13–46 km; 16–22 m; 4 December 1962; M. Gray: 1 (2.9).

GULF OF MEXICO. South of Cape San Blas, Florida; 29°15230″N, 85°29′30″W; 49 m; gravel; 7 February 1885; large beam trawl; Albatross Sta. 2372: 1 (3.6). Anclote Light, Florida, E 7/8 N–39.8 km; 23 m; rock, coral, and sand; 17.2°C; 28 March 1901 (10:30 a.m.); dredge; Fish Hawk Sta. 7106: 1 (3.2). Southwest of Sarasota, Florida; 27°04′00″N, 83°21′5″W; 48 m; coarse gray sand and broken shell; 18 March 1885; large beam trawl; Albatross Sta. 2409: 1 (3.9). West of Captiva Island, Florida; 26°33′N, 83°10′W 51 m; sandy; 19.1 °C; 2 April 1901 (6.30 a.m.); 7-ft beam trawl; Fish Hawk Sta. 7123: 1 ovig. (3.9). West of Marco Florida; 26°04′00″N, 82°49′00″W; 39 m; sand and broken shell; 17 March 1889; hand dredge; Grampus Sta. 5099: 1 ovig. (4.4). 25°54′00″N, 83o20′00″W; 57 m; gray sand with black specks and broken shell; 15 March 1889; hand dredge; Grampus Sta. 5092; 2 (3.2, 3.9) (1 ovig. (3.2)). Northwest of Dry Tortugas; 25°34′00″N, 83°28′00″W; 71 m; gray coral and fine shell; 1 March 1889; hand dredge; Grampus Sta. 5076: 1 (3.8).

HABITAT.—In depths of 20 to 202 meters, usually less than 70 meters, commonly on bottoms of sand, frequently with shell fragments, occasionally on gravel, rock, and coral, at bottom temperatures ranging from 9° to 20.6°C.

There is no evidence from the material available that L. (L.) papulata approaches the surface at night, as do L. (L) bermudensis and L. (L.) serratorbita, but additional surface or subsurface collections in the region inhabited by the former species may refute this assumption; the fact that, on four different occasions, specimens of L. (L.) papulata were found in grab samples indicates that the species must spend some time in actual contact with the bottom.

TYPE-LOCALITY.—East of Cape Lookout, North Carolina; 34°35′30″N, 75°45′30″W; 59 meters.

DISPOSITION OF TYPES.—The ovigerous female holotype (USNM 23375) and the rest of the type-series are deposited in the National Museum of Natural History, Smithsonian Institution, under the catalog numbers of the United States National Museum (USNM).

DISTRIBUTION.—Off North Carolina to Georgia and the eastern Gulf of Mexico, in depths of 20 to 202 meters.

ETYMOLOGY.—From papula (L., = pimple) + atus (L., = provided with), in reference to the one to three elevations usually present in the dorsal midline of the fifth abdominal somite.