Leptochela serratorbita Spence Bate 1888

Leptochela (Leptochela) serratorbita Bate

Leptochela serratorbita Bate, 1888:859, pl. 139: fig. 1.—Young, 1900:497—Rathbun, 1901:127.—Schmitt, 1935:134, fig. 7.— Lum, 1939:335.—Springer and Bullis, 1956:10.—Williams, 1965:41, figs. 33, 34.—Chacc, 1972:16.

Leptochela serratorbita?.—Chacc, 1937:111.

DIAGNOSIS.—Rostrum with dorsal margin straight, concave, or sinuous, rarely convex. Carapace without longitudinal dorsal ridges in either males or females. Orbital margin minutely spinulose dorsolaterally, with mesially directed rectangular or obtuse tooth on ventral portion; suborbital angle dentate. Fifth abdominal somite entire, without dorsal elevations or posterior tooth. Telson with 2 pairs of dorsolateral spines in addition to anterior mesial pair; posterior margin with pair (frequently fused, rarely absent) of minute mesial spines in addition to usual 5 pairs of prominent spines. Antennal scale more than ½ but less than 1/3 as long as carapace. First pereopod with 9 to 29 spines on opposable margin of movable finger. Second pereopod with 13 to 37 spines on opposable margin of movable finger. Third pereopod with exopod not nearly reaching distal end of ischium. Endopod of 1st pleopod of male rather narrowly rounded distally. Appendix masculina, not including spines, occasionally reaching to or slightly beyond distal end of appendix interna. Maximum carapace length 4.1 mm.

DESCRIPTION.—Rostrum (Figure 29a,b) with dorsal margin variable, straight, concave, sinuous, or rarely convex, falling slightly short of or reaching slightly beyond level of distal margin of basal segment of antennular peduncle. Carapace without median or dorsolateral carinae or ridges in either males or females. Orbital margin (Figure 29b,c) minutely spinulose dorsolaterally, with mesially directed rectangular or obtuse tooth on ventral portion; suborbital angle dentate.

Abdomen (Figure 29d) rounded dorsally on 3 anterior somites, usually bluntly carinate on at least posterior part of 4th and all of 5th. Fifth somite entire, without dorsal prominences or posterodorsal tooth. Sixth somite nearly twice as long as high, with usual transverse swelling near anterior end of dorsal surface, relatively short slender spine on ventrolateral surface, and rather strong acute tooth on posterodorsal margin of posterolateral lobe (Figure 29). Telson (Figure 29f) nearly ½ times as long as 6th somite, fully 3 times as long as wide, armed with 2 pairs of dorsolateral spines, posterior pair near midlength, in addition to anterior mesial pair; posterior margin (Figure 29g) bearing pair (frequently fused, rarely absent) of minute spines (Figure 29h) between bases of mesial pair of usual 5 pairs of prominent spines.

Eye (Figure 29c) with papilla (visible only in oblique view) on dorsomesial surface of stalk at juncture with cornea, cornea slightly wider than stalk.

Antennular peduncle (Figure 29i) with stylocerite reaching about as far as distolateral margin of basal segment; 2nd segment about as long as distal segment in ventromesial aspect, much shorter in dorsal aspect.

Antennal scale (Figure 29) 0.5 to 0.6 as long as carapace, 2.9 to 4.4 times as long as wide, lateral margin noticeably concave at about midlength, distal tooth usually continuous with mesial margin of blade, latter rarely with suggestion of subdistal shoulder. Distal segments of antennal peduncle about 2/5 as wide as scale, not nearly reaching midlength of scale; ventral tooth on basal segment neither prominent nor very sharp.

Mouthparts as illustrated (Figure 30a-f). Mandible (Figure 30a) with distal margin faintly concave. Third maxilliped (Figure 30f) rarely reaching as far as distal end of antennal scale, distal segment more than 2/5 as long as penultimate segment.

First pereopod (Figure 30g) usually overreaching antennal scale by less than length of fingers; fingers 1.4 to 2.1 times as long as palm; dactyl (Figure 30i) armed with 9 to 29 spines on opposable margin. Second pereopod (Figure 30i) overreaching antennal scale by less than length of fingers; fingers 1.5 to 2.4 times as long as palm; dactyl (Figure 30f) armed with 13 to 37 spines on opposable margin. Third pereopod (Figure 30k) overreaching anterior margin of carapace by combined lengths of dactyl and propodus; exopod not nearly reaching distal end of ischium; ischium bearing row of 3 long spines near flexor margin and subdistal spine on extensor margin; merus armed with 5 or more similar spines near flexor margin; dactyl distinctly shorter than propodus. Fourth pereopod (Figure 30Z) reaching nearly to midlength of ischium of 2nd pereopod when both extended anteriorly; dactyl usually longer than propodus. Fifth pereopod (Figure 30m) similar to and little shorter than 4th, reaching to about midlength of ischium of 3rd pereopod when both extended anteriorly; dactyl usually longer than propodus.

Endopod of 1st pleopod of male (Figures 31a, b) rather narrowly rounded distally, lateral margin convex, not flared distally. Appendix masculina (Figure 31c,d) bearing 6 long spines and occasionally reaching to end of or slightly beyond appendix interna, not including spines. Lateral branch of uropod (Figure 29f) armed with 7 to 13 spines.

SIZE.—Carapace length of males, 1.5–3.7 mm; of females without eggs, 1.6–4.1 mm; of ovigerous females, 2.7–3.9 mm.

MATERIAL.—NORTH CAROLINA. Beaufort; 6 November 1929; J. S. Gutsell: 1 (4.1).

GULF OF MEXICO: Cayos Areas, Bahia de Campeche; 18 m; 11 December 1952; from bonefish stomach; Oregon: 13 (2.8).

FLORIDA KEYS. Key West; 1884; electric light at surface; Albatross (W. Nye): 81 (2.5–3.4) 43 (2.0–3.6) (4 ovig. (2.9–3.0)).

PUERTO RICO. Playa de Fajardo; 23 February 1933; 8-foot circular net under cargo light; Johnson-Smithsonian Deep-sea Expedition: 115 (2.0–3.7) 35 (1.7–3.6) (1 ovig. (3.4)) 1?. Cayo Icacos; 24 February 1933; 8-foot circular net with cargo light and submarine light; Johnson-Smithsonian Deep-sea Expedition: 3 (1.8–2.6) 5 (2.2–3.0). Off Isla de Vieques; Culebritas lighthouse NE 1/2 N 18.5 km; 27 m; coral; 8 February 1899; tangle; Fish Hawk Sta. 6091: 1 ovig. (2.7). Off Isla de Culebra; Culebritas lighthouse NE 9.7 km; 27 m; coral; 8 February 1899; tangle; Fish Hawk Sta. 6093: 4 (2.5–3.0). Canal de Luis Peña, Isla de Culebra; 25 February 1938; 8-foot circular net under cargo light; Johnson-Smithsonian Deep-sea Expedition: 25 (2.1–3.3) 2 (2.6, 2.8). Same; 3-foot net towed from port launch: 4 (2.3–2.5).

VIRGIN ISLANDS. Brewers Bay, Saint Thomas; 1 March 1933; 8-foot circular net under cargo light; Johnson-Smithsonian Deep-sea Expedition: 15 (15-2.4) 53 (1.6–2.8). Saint Thomas; 17-24 January 1884; Albatross: 8(1.9–3.0) 2 (2.6) 1? (2.3). Sopers Hole, Tortola; 5-11 m; shells and compact sand; 1 April 1958; dredge; Smithsonian-Bredin Caribbean Expeditions Sta. 25-58; 23 (2.6, 2.7). Off Vixen Point, Prickly Pear Island, Virgin Gorda; 6 April 1958; 9:00 p.m.; light at bottom at anchorage in 20 m; Smithsonian-Bredin Caribbean Expeditions Sta. 36b-58: 1 juv. (0.8).

LEEWARD ISLANDS. Off Oyster Pond Landing, west side of Barbuda; 5 April 1956; 7:00-8:30 p.m.; light over side at anchorage in 5½ m; Smithsonian-Bredin Caribbean Expeditions Sta. 84-56: 222 (2.3–3.6) 200 (2.6–4.0) (8 ovig. (3.0–3.9)). South of Bird Island, Nonsuch Bay, Antigua Island; 23 April 1958; light over side at anchorage in 7 m; Smithsonian-Bredin Caribbean Expeditions Sta. 93-58: 13 (3.4).

HABITAT.—In or over depths of 5½ to 27 meters. It may be noted that 8 of the 15 lots and all but 25 of the 826 specimens studied were taken under a light at the surface at night. See discussion of the habitat of L. (L.) bermudensis and remarks under L. (P.) carinata.

TYPE-LOCALITY.—Saint Thomas, Virgin Islands.

DISTRIBUTION.—North Carolina and western Gulf of Mexico to the Leeward Islands, in and over depths of 5½ to 27 meters.

Reexamination of the material collected at the surface beneath a light and dredged in 15-29 meters on a sandy bottom at San Lucas, Baja California, tentatively assigned to L. (L.) serratorbita by Chace (1937) has revealed no obvious differences from western Atlantic populations, but a more thorough comparison would be desirable when additional adult specimens become available from the eastern Pacific.

DISTRIBUTION.—If my conclusions are correct (see “Remarks”), L. sydniensis is known from the Arabian Sea, the Bay of Bengal, the South China and Yellow seas, and Japanese waters, as well as off the southeastern and southern coasts of Australia.