FISHERY BULLETIN: VOL. 83, NO. 1 



oval, long axis disposed either longitudinally or 

 transversely). Median plate of sternite XIII 

 flaskshaped in outline, tapering into long, slender 

 spine reaching between anterior and posterior ex- 

 tremities of coxa of anteriorly extended second 

 pereopods; plate constricted, its ventral surface 

 strongly excavate at level of coxae of fourth 

 pereopods; posterior component of plate, with 

 rounded posterolateral margins and broad shal- 

 low, median emargination. Paired, broad based 

 spines projecting anteriorly from posterior margin 

 of sternite XI. Posterior thoracic ridge narrow, 

 with concave, sharp anteromedian margin but 

 merging laterally with preceeding plate. 



The smallest impregnated females encountered 

 have a carapace of 8 mm, about 31 mm tl. 



Color. — Specimens preserved in Formalin'* buff 

 with purplish blue markings: antenna, lateral 

 ridge of scaphocerite, postrostral and abdominal 

 carina, and dorsal ribs of telson transversely 

 banded; anterior margin and posterior ridge of 

 carapace, anterior margin of pleuron of first ab- 

 dominal somite, and posterior margin of all ab- 

 dominal somites with series of small spots; tip of 

 teeth on rostrum, carapace, and first abdominal 

 somite also purplish blue; lateral ramus of uropod 

 with subterminal spot on lateral ridge and large 

 mesial blotch at same level. 



Maximum size. — Males 15.6 mm cl, 60.5 mm tl; 

 females 22.5 mm cl, 87.2 mm tl. 



Geographic and bathymetric ranges. — From 

 southwest of Isla Santa Margarita (24°19'48" 

 N, lir47'06"W - 24°19'36"N, lir47'06"W), 

 Baja California Sur, Mexico, to southern tip of 

 Baja California Sur and throughout the Gulf of 

 California southward to off Punta Lizardo 

 (18°06'00"N, 102°5718"W), Michoacan; also from 

 E of Puerto Angel (15°41'00"N, 96°07'30"W), 

 Oaxaca, Mexico, to SW of Punta Ana Maria 

 ( 7°50'30"N, 78°49'00"W - 7°50'48"N, 78°48'00"W), 

 Panama (Fig. 38). It has been found at depths 

 between 9 and 242 m, on substrates of sand, rock, 

 mud, and coralline debris. 



D/scuss/on. — Although closely allied to S. affinis 

 and S. aliaffinis, S. martini can be distinguished 

 readily from both of them by the length, shape, and 

 armature of the rostrum; the shape of the tooth on 



Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



56 



the first abdominal somite; the sculpture of the ab- 

 domen; and features of the petasma and thelycum. 



In S. martini the rostrum is quite long, surpass- 

 es the eyes, and almost reaches the distal margin 

 of the second antennular article. In males, the 

 rostrum is straight or upturned at an angle of no 

 more than 10°, and armed with three dorsal teeth 

 and three or four apical teeth, the ventral one of 

 which is occasionally subterminal. In females, the 

 rostrum is strongly elevated (40°-50°), with its 

 ventral margin usually markedly convex in the 

 middle and concave posterior to the base of the 

 subterminal tooth, and bears two dorsal teeth and 

 three to five apical teeth, the ventral one of which 

 lies distinctly posterior to the adjacent tooth. In S. 

 affinis and S. aliaffinis the rostrum is shorter than 

 in S. martini, reaching at most the distal margin 

 of the eye; in both males and females it is upturned 

 at an angle of about 30°, thus more elevated than 

 in males of S. martini but less so than in females, 

 and its ventral margin is usually straight or, occa- 

 sionally, slightly convex basally. Also, in these two 

 species the rostrum is armed with only two dorsal 

 teeth, and the ventral of the two or three apical 

 teeth (four or five have not been observed) is ter- 

 minal, instead of subterminal as it is in all females 

 and some males of S. martini. 



The tooth on the first abdominal somite is pro- 

 portionately higher in S. martini than in the other 

 two species; its dorsal margin is sigmoid and it 

 ends in a strong, recurved, hooklike tip. In S. 

 affinis and S. aliaffinis the dorsal margin of the 

 tooth is gently curved in an arc, and the tooth is 

 inclined more anteriorly than in S. martini; in S. 

 affinis it ends in a slightly curved tip, and in S. 

 aliaffinis the tip is triangular rather than hook- 

 like. Also, the abdominal sculpture of S. martini is 

 much stronger than that of its two closest congen- 

 ers, and exhibits unusual, longitudinally disposed, 

 inverted V-shaped ridges at the ventral end of the 

 dorsal third of the second and third somites, which 

 are absent in the other two species. 



In S. martini, the projection of the dorsolateral 

 lobule of the petasma is bifurcate apically, the tips 

 sharp. In S. affinis and S. aliaffinis, the projection 

 is compressed distally with the ventral extremity 

 rounded, the dorsal extremity sharply produced in 

 a simple spine, and the distal margin (im- 

 mediately ventral to the spine) truncate or 

 slightly emarginate. Furthermore, the projection 

 of the ventrolateral lobule of the petasma of S. 

 martini, like that of S. affinis but in contrast to 

 that of S. aliaffinis, is flattened distally rather 

 than thickened (dorsally) into a subovoid pro- 



