NOTES ON A SMALL COLLECTION OF RAJIDS FROM THE SUB-ANTARCTIC REGION1 Henry %. Bigelow and William

Transcription

1 NOTES ON A SMALL COLLECTION OF RAJIDS FROM THE SUB-ANTARCTIC REGION1 Henry %. Bigelow and William C. Schroeder Woods Hole Oceanographic Institution and Harvard University ABSTRACT Five species of raiids from the Pataaonian-Falkland Islands-South Georgia Island regions and off Valparaiso, Chile are described INTROlXJCTION This report deals with a small collection of rajids from the Pa tagonian-falkland Islands-South Georgia Island regions and off Valparaiso, Chile. Five species, all of them previously described, arc included. Major works dealing with the fish fauna of this area include those by Norman ( 1937, 1938) and Hart ( 1946), both of which cover the trawling surveys made by RRS William Scoresby in April 1927, June-July 1928 and October-April , together with some material from the RRS Discovery trawlings. For the opportunity to work up this collection we thank Dr. Hugh H. Dewitt who is in charge of the benthic fishes collected during a continuing program of Antarctic biological research by the University of Southern California, sponsored by the National Science Foundation. The survey has been made by the USNS Eltanin. Our species descriptions follow the form used by Bigelow and Schroeder (1953). RAJA GEORGZANA NORMAN ( ID 3 8 ) The original account of this species is based on a single specimen, a female 185 mm in total length with a disc 140 mm wide, trawled in East Cumberland Bay, South Georgia Island, in m depth. Study material An immature male 440 mm in total length (Fig. 1)) from the offing of South Georgia Island, S lat, W long, in m, USNS Eltanin station _ Contribution No from the Woods Hole Oceanographic Institution, Woods Hole, Massachusetts. 732; a mature male of 860 mm from 54O40.8 S lat, W long, in m, station 671; a male of 189 mm and a female of 206 mm from S lat, W long, in m, station 731. Our mm specimens agree closely with Norman s description of the type. He points out that it appears to be most nearly related to R. maczoviana Norman (1937) from the Patagonian region, and to R. murrayi Giinther ( 1880) from Kerguelcn, but differs from both in shape of disc, in smaller eyes, in greater internasal width, and in the form and arrangement of spines. Tts greater number of thorns (24-28) in the midrow on disc and tail and more prickly and thorny disc distinguishes R. georginnn from R. doello-iurudoi Pozzi ( 1935)) which has thorns in the midrow and scattered spines on the disc. The more rounded outer corners of disc, axis of greatest breadth of disc 7481% backward from tip of snout toward axils of pectorals, and pale lower surface, set R. georgiana apart from R. bad&z Garman ( 1899), which has the corners of disc abruptly rounded, the axis of greatest breadth about 89% backward, and the lower surface dark brown. Description of mule 440 mm in total length-proportional dimensions in per cent of total length. Disc-Extreme breadth, 86.0; length, Snout length-in front of orbits, 14.8; in front of mouth, Orbits-Horizontal diameter, 4.8; distance between, 7.3. Spiracles-Length, 3.4; distance between, Mouth-Breadth, R38

2 RA JIDS FROM SUB-ANTARCTIC REGION R39 FIG. 1. Raja georgiana An immature male, 440 mm long, from off South Georgia Island. Exposed nostrils-distance between inner ends, Gill openings-length: lst, 1.7; 3rd, 1.8; 5th, 1.4; distance between inner ends: lst, 22.0; 5th, First dorsal fin-height, 2.5; length of base, 4.6. Second dorsal fin-height, 2.5; length of base, 5.4. Pelvics-Anterior margin, Distance-From tip of snout to center of cloaca, 50.5; from center of cloaca to 1st dorsal 36.0; to tip of tail, 49.5; from rear end of 2nd dorsal base to tip of tail, 3.0. Interspace-1st and 2nd dorsals, 0.5. Disc 1.42 times as broad as long; maximum angle in front of spiracles 113 ; tip of snout sharply rounded; anterior margins of disc slightly undulate about midway between tip of snout and outer angle which is narrowly rounded; posterior margins nearly straight, rounded at inner corners. Axis of greatest breadth 77% backward from tip of snout toward axils of pectorals. Tail rather slender, tapering evenly to tip; the lateral folds, low down, originate at the axils of the pelvics, as a thickened ridge, gradually widening rearward, reaching tip of tail; length of tail from center of cloaca to origin of first dorsal 0.71 times as great and to its tip 0.98 times as great as distance from center of cloaca to tip of snout. Upper surface exceedingly thorny, the entire disc and tail covered with an assortment of prickles, small thorns, and large thorns. These are distributed chiefly as follows: One large thorn at inner anterior margin of orbit, one at inner rear margin, and one a little posterior to spiracle, the three thorns nearly in line; a row of 28

3 R40 HENRY B. BIGELOW AND WILLIAM C. SCHROEDER formidable thorns from nuchal region to first dorsal, without interruption, the thorns becoming progressively smaller and closer together posteriorly, with a heavy base and sharp tips bent rearward; a pair of scapular thorns on each side, one behind the other. Rest of disc and tail covered with thorns and prickles of various sizes and in complex arrangement, the least spinous area being a band along the outer angle and rear margin of disc which lacks thorns and where the prickles are minute and more easily felt than seen. Pelvics with a large patch of prickles on central area of posterior lobe; dorsals, caudal, and skin over eyes, all prickled; one small thorn each side of the very small interdorsal space. Lower surface smooth except for a few minute prickles on tip of snout. Snout in front of orbits 3.2 times as long as orbit, its length in front of mouth 1.4 times as great as distance between exposed nostrils. Distance between orbits 1.5 times as great as length of orbit. Orbit 1.4 times as long as spiracle. Nasal curtain coarsely fringed on rear margin and along its outer margin, the latter fringe less prominent; outer margin of nostril flap smooth-edged. Upper and lower jaws moderately arched. Teeth 42/40 ( uppers and lowers), small, arranged in quincunx, with nearly circular base and narrow cusp directed somewhat inward. Distance between first gill openings 1.9 times as great as between exposed nostrils; between fifth openings 1.4 times; second, third, and fourth gill openings slightly longer than first and 1.3 times as long as fifth. Dorsal fins similar in shape, the base of second 1.17 times length of base of first, with a barely perceptible interspace. Caudal very small, confluent with second dorsal. Pelvics deeply concave outwardly, anterior lobe stout, about % as long as distance from its own origin to rear tip of pelvic; margins of both anterior and posterior lobes scalloped, outer margin of latter broadly rounded, inner margin about straight. Rostra1 cartilage firm; extending forward to within one orbit s length of tip of snout. Anterior rays of pectorals reaching % the distance from front margin of orbits toward tip of snout. Claspers immature, failing to reach tip of pelvics by about 1 orbit length. Color above, disc greyish brown with numerous rather widely scattered pale spots of irregular shape, the spots also present on pelvics, along sides of tail and with one spot on each dorsal and the tiny caudal. Below, the disc is whitish with a light greyish band along outer margin, beginning opposite third gill opening, widest at outer angles, the inner margin of band irregular. A small area of faint greyish markings is present in front of the base of the anterior pelvic lobes, including an oblique series of 4 or 5 very small roundish grey spots; anterior lobe of pelvics with grey markings followed by 3 spots along margin of the anterior part of the posterior lobe. Tail pale, with a narrow greyish stripe extending along midline. The 8%mm specimen agrees closely in proportional dimensions. The maximum angle of disc in front of spiracles is 107 and the anterior margin of disc more conspicuously undulate. The distribution of thorns and prickles on the disc and pelvics is much the same except for the presence of malars and alars. There are 27 thorns in the midrow from the nuchal region to the first dorsal, several of the anterior ones worn down; 3 scapular thorns on each side of the midrow, forming a triangle, and a row of small thorns low down each side of the midrow on the tail. A patch of sharp malar thorns is present opposite the orbits. The alar thorns, on the outer part of the pectorals, are well developed, very sharp, pointing inward, in only 2 rows, the longest row equal to the distance from the tip of snout to the anterior margin of the orbits. Smooth below. The nasal curtain has but one fringe along its outer margin. Upper and lower jaws strongly arched. Teeth 38/34. The claspers are massive, extending % the distance from axils of pelvics toward the first dorsal fin. Color above brown, with vague pale markings on disc, pelvics, and tail, and with 1 or 2 very small whitish blotches on the claspers. Below, the disc is whitish

4 RA JIDS FROM SUB-ANTARCTIC REGION R41 of m. IIart (1946, p. 262) increased this number to 30 fcmalcs and 38 males, from 12 stations all taken within this same arca. FIG. 2. Raja doello-iuradoi. Recently hatched fcmalc, 100 mm long, from the Strait of Magcllan. with a grey band along the outer margin from opposite the mouth to the axils of pectorals, widest at outer angles, its inner margin irregular. There are patches of grey below the mouth, and a large one in front of each pelvic fin, a greyish blotch at the excavations of the pclvics and a grey stripe along the center of the tail throughout its length. Compared with the larger specimens, the two juveniles have a relatively shorter disc, % of total length. The arrangcmcnt of the major thorns are in close agreement, thcrc being 3 orbitals, 3 scapulars forming a triangle, and 24 in the midline to the first dorsal, all thorns very sharp. Teeth 38/34-39/36. The most striking clifferencc is in color, the brown of the upper surface being marked with a pale reticulation on the disc and pelvics, the design more in the form of bars on the tail. Pale below. The male is not as intensely marked as the female. Known from the vicinity of South Georgia Island in depths of m. RAJA DOELLO-JURADOI POZZI ( 1935 ) Norman s ( 1937) account of this species is based on 5 females mm in total length and 7 males of loo-430 mm, from 10 stations, trawled between S lat and W long in depths A recently hatched fcmalc 100 mm in total length, from the Strait of Magellan, S lat, W long, in 485 m, USNS Eltmin station 963 (Fig. 2). This specimen differs from our two smallest R. georgiana ( mm long, p. R38), which it most closely resembles, chiefly as follows : The disc width is about 3% the total length oe the specimen, the intcrorbital width slightly less than diameter of orbit, internarial width 56% of the distance from snout to mouth, and there are 17 thorns in the midline from nuchal region to first dorsal. On the two R. georgibnn, the disc width is about g total length, interorbital about 1.4 times diameter OF orbit, internarial 71-77% of distance From snout to mouth and there are 24 thorns in the midline on both specimens. Known from Argentina and Patagonian- Falklands region. BREVIRAJR I3RACIIYUROPS ( FOWLER, ) Norman ( 1937) lists a total OF 84 spccimens mm in total length from 30 stations between S lat and W long in depths OF His dcscrip tion includes the two Challenger types (Gunther 1880, as Rnjn hmchyurn, name preoccupied ), a male of 693 mm and a female of 826 mm in total length, from m depth, taken west of the Strait of Magellan. Hart ( 1946) found B. bmchyurops to be the most abundant skate taken during the trawling surveys, He increased the above totals to 274 individuals from 48 stations, caught within the same area, Study mterinl A female 372 mm in total length from Rurwood Bank, S lat, W long, in 120 m, USNS Eltnnin station 343 and an immature male of 593 mm ( Fig. 3)) from east of the Strait of Magellan, S lat, W long, in 128 m, station 976.

5 1342 IIENRY B. BIGELOW AND WILLIAM C. SCHROEDER FIG. 3. Bwuiraja brachywops. An immature malt, 593 mm long, from cast of the Magellan. Strait : of R. hrachyurops is closely related to B. griseocauda (Norman, 1937). In comparing the two species, Norman (1937) points out that the latter has a proportionately longer tail, measured from the cloaca, no median spines on the disc anteriorly, stronger tail spines, and spinules on the disc that are a little larger, less numerous, and rather wider apart. Ckscriptio~Proportional dimensions in per cent of total length of the 372 mm Eemale and 593 mm male. Disc-Extreme breadth, 76.0, 69.0; length, 58.4, Snout length-in front of orbits, 14.2, 14.2; in front of mouth, 16.4, Orbits-Horizontal diameter, 5.1, 5.4; distance between, 5.1, 4.9. Spiracles-Length, 3.0, 2.7; distance bctween, 8.6, 8.4. Mouth-Breadth, 8.2, 8.5. Exposed nostrils-distance between inner ends, 8.4, 8.3. Gill openings-length: lst, 1.3, 1.3; 3rd, 1.3, 1.4; 5th, 1.3, 1.2; distance between inner ends: lst, 18.8, 17.4; 5th, 12.4, First dorsal fin-height, 3.8, 3.5; length OF base, 4.6, 4.5. Second dorsal fin-height, 3.8,3.5; length of base, 3.8, 4.1. Pelvics-Anterior margin, 12.1, Distance-From tip of snout to center of cloaca, 53.2, 53.7; from center of cloaca to first dorsal, 36.0, 35.5; to tip of tail, 46.8, Interspace-1st and 2nd dorsals, 1.3, 0.8.

6 RA JIDS FROM SUB-ANTARCTIC REGION R43 Disc 1.3c1.19 times as broad as long, maximum angle in front of spiracles ; snout with a small roundish projection; anterior margins of disc slightly undulate, outer corners moderately rounded, posterior margins gently convex. Axis of greatest breadth 69-68% backward from tip of snout towards axils oe pectorals. Tail robust, its lateral folds originating as a ridge opposite axils of pelvics, widening posteriorly, reaching tip of tail; length of tail from center of cloaca to origin 0F first dorsal times as great and to its tip times as great as distance from center of cloaca to tip of snout. Upper surface of disc of fcmalc with small prickles in advance of axis across spiracles, in a broad band along margins of disc nearly to outer angles and along midsector from nuchal region on to and along sides of tail to its tip. No orbital thorns. A midrow of sharp, backward pointing prominent thorns, three between the nuchal region and scapular arch followed by 17 between the axils of pectorals and first dorsal, the gap covered with prickles, the thorns of about the same size and rather evenly spaced; one thorn bctwecn dorsals; a few prickles on skin over eyes, on dorsals and on caudal fin, Pelvics smooth. Lower surface of disc and tail smooth. On the male, the distribution of thorns and prickles is essentially the same as on the female, the chief variation being that there are but two nuchal-scapular thorns and 12 from a little posterior to axils of pectorals to the dorsal. There is one in- complete row of alar thorns on the outer part of each pectoral. Norman (1937, p. 26) states that mature males have two, three, or more series of alar spines. Snout in front of orbits times as long as orbit, its length in front of mouth 2.0 times as great as distance between exposed nostrils. Distance between orbits times length of orbit. Orbit times as long as spiracle. Nasal curtain and expanded outer margin of nostril flap with a coarse fringe. Jaws slightly arched. Teeth in 28/28 series in the female, 30/30 in the male, arranged chiefly in quincunx, with slightly oval base and narrow triangular cusp, many of them blunted. Distance between first gill openings times as great as between exposed nostrils; bctwecn fifth openings times. Dorsals similar in shape, the first slightly the larger, with a small interspace. Caudal fin exceedingly small, its base only about X< that of the second dorsal with which it is confluent. Pclvics clecply concave outwardly, scalloped at excavation, anterior lobe stout, about?@$ as long as distance from its own origin to rear margin of pelvic which is narrowly rounded. The claspers of the male extend but slightly beyond the tips of the pelvics. Rostra1 cartilage with a short triangular base, firm, extending forward only about!z the distance from anterior rim of orbits toward tip of snout, its continuation narrow and flexible. Pectoral rays reaching nearly to tip of snout, their anterior ends close togcthcr. Color of upper surface of disc of fema.lc light brown with a mixture of pale and darkish brown spots of various sizes and shapes, a few appearing as obscure ocelli and with one ocellus, pale centered with a dark margin, oval in shape, situated on the rear third of each pectoral. Tail less distinctly marke,d. Dorsals plain light brown. Lower surface of disc and tail yellowish, but whitish when mucus is removed. The malt is dark brown above, spotted, with the pair of ocelli clongato in shape. Below, the disc is white with a few small irregular greyish blotches scattered along the postcrior margin, the tail with an irregular band of grcy along its midscctor posteriorly. Known from the Patagonian-Falklands region and Strait of Magellan. BREVIRAJA GRISEOCAUDA ( NORMAN, 1:) R 7 ) Norman s ( 1937) brief description of this species is based on 1 female (the holotypc) 460 mm in total length and 5 males of mm total length trawled at 5 stations bctwecn V S lat and W long in depths of m.

7 R44 T-TENllY B. BIGELOW AND WILLJAM C. SCEI1~OEDEI~ FIG. 4. Breviraja griseocauda. A mature male, 490 mm long, from off South Shetland Islands. Hart (1946, p. 270) increased the number of specimens to 8 and added 1 station at S lat, W long. Study material A mature male 490 mm in total length (Fig. 4)) from northeast of South Shetland Islands, S lat, W long, in m, USNS Eltanin station 410, and a female of 258 mm from northeast of Clarence Island, S lat, W long, m depth, station B. griseocauda closely resembles B. spinicauda (Jensen, 1914) of the North Atlantic Ocean. In our account of this species, as Raia spinicauda, (,Bigelow and Schroeder 1953, p ), based chiefly on a specimen 1,236 mm long, we stated that the anterior rays of the pectorals extend forward about 85% of the distance from levd of fronts of orbits toward tip of snout, but we omitted mention of the rostra1 process. However, we failed to recognize that it actually agreed with our

8 RA JIDS FROM SUTbANTARCTIC REGION R45 description of Ureviraja gen. nov. (Bigelow and Schroeder 1948, p. SSS), in which the rostra1 cartilage falls short of the anterior rays of the pectorals that may be either close together anteriorly or farther separated. Subsequently, we obtained a B. spinicaudu, a male 382 mm long, from N lat, W long, that is an undoubted Breviraja, its firm rostrum short, triangular, extending a little less than h the distance in advance of orbits toward tip of snout, with the anterior pectoral rays reaching nearly to end of snout, their tips close together. Our 490-mm male B. griseocc~ucln, which is mature, has an anterior angle of disc in front of spiracles of 117, the distance from snout to mouth is 12.5% of the total length of the specimen, and the jaws are moderately arched. On the 382#- mm male B. spinicauda, which is a juvenile, the anterior angle is 99, distance from snout to mouth 19.4%, and the jaws arc virtually straight. A B. spinicauda of 1,236 mm is not yet fully mature (Bigelow and Schroeder 1953, p. 271). B. griseocauda appears to bc closely rclated to B. scaphiops ( Norman, 1937) and to B. eatonii (Gunther, 1876), but it has a much more prickly disc and tail and a larger number of thorns (20-27) along the midline of tail. B. scaphiops is described as having the upper surface of disc mainly smooth, but with areas of minute spinules on anterior parts of pectorals, on snout, round the eyes and on back and the median series, extending from the pelvic region to the first dorsal fin, numbers 17 to 19. I?. eatonii has the greater part of the upper surface of disc smooth, a single large recurved spine on the middle of back, and a series of 9 or 10 small spines rather widely spaced along the midline of the tail. Norman concluded that B. griseocauda was close to B. brachyuropls (see p. 1~41)) but the latter has a row of one to five spines from the nuchal to the scapular region, although very occasionally they are absent. We find, also in comparing our two specimens of each species, that I?. griwocauda has a shorter snout, its distance to mouth % of the total length of the speci- mens (B. brachyurops %), and a smaller distance, %, between the first pair of gill openings (B. brachyurops % ). Description of 490-mm male-proportional dimensions in per cent of total length: Disc-Extreme breadth, 67.6; length, Snout length-in front of orbits, 12.0; in Eront of mouth, Orbits-Horizontal diameter, 4.1; distance bctwecn, 3.9. Spiracles-Length, 3.1; distance between, 8.0. Mouth-Breadth, 7.6. Exposed nostrils- Distance between inncr ends, 7.0. Gill openings-length: lst, 1.4; 3rd, 1.4; 5th, 1.0; distance between inner ends: lst, 14.3; 5th, 9.0. First dorsal fin-height, 2.5; length of base, 3.7. Second dorsal fin-iieight, 2.5; length of base, 3.7. Pelvics-An tcrior margin, Distance-From tip of snout to center of cloaca, 47.0; from center of cloaca to 1st dorsal, 43.3; to tip of tail, 53.0; from rear end of 2nd dorsal base to tip of tail, 2.3. Interspace-1st and 2nd dorsals, 0.0. Disc 1.27 times as broad as long; maximum angle in front of spiracles 117 ; tip of snout projecting slightly; anterior margins of disc gently convex to opposite orbits thence slightly concave toward outer corners which are broadly rounded; posterior margins convex, inner margins nearly straight. Axis of greatest breadth 75% rearward from tip oe snout toward axils of pectorals. Tail rather slender, tapering evenly to tip; the lateral folds, low down, originate a little posterior to axils of pclvics, reaching tip of tail, very narrow anteriorly, widening posteriorly; length of tail from center of cloaca to origin of first dorsal fin 0.92 times as great, and to its tip I.13 times as great as distance from center of cloaca to tip of snout. Upper surface of disc with small closely spaced prickles, anteriorly and along a

9 R46 HENRY B. BIGELOW AN D WILLIAM C. SCTIROEDER broad band centrally, but sparce opposite alar thorns, the tips of most of them directed from slightly to sharply rearward, the base with 4 radii; coarse prickles in a wide band along the outer part of disc, following the lines of the pectoral rays. Alar thorns well developed, sharp, pointing obliquely inward and backward along the anterior half oe the patch, directly inward on the posterior half, in as many as five rows, the length of patch equal to distance from tip of snout to center of orbit, its greatest width a little more than interorbital space. Tail densely covered with small prickles, their bases touching; dorsal fins and skin over eyes also with prickles. Pelvics smooth. No orbital, scapular, or nuchal thorns. A median row of 20 sharp thorns beginning a little anterior to axils of pclvics, reaching nearly to first dorsal, with a stout, vertical, cone-shaped base, the tips, sharp on those not blunted, pointing slightly rearward, the last 3 thorns the smallest. Lower surface of disc, pelvics, and tail smooth. Snout in front of orbits 2.9 times as long as orbit, its length in front of mouth 1.8 times as great as distance between exposed nostrils. Distance between orbits nearly as great as length of orbit. Orbit 1.3 times as long as spiracle. Nasal curtain and expanded outer margin of nostril flap smoothedged. Jaws moderately arched. Teeth 26/Z& arranged in oblique rows, except the median pair, with slightly oval base, uppers with the seven teeth on each side of midline with a rather narrow triangular cusp, the others with a broadly triangular cusp; lowers with broadly triangular cusp near center of mouth, the cusps barely perceptible toward its corners. Distance between first gill openings 2.0 times as great as between exposed nostrils; between fieth openings 1.3 times; first to fourth gill openings 1.4 times as long as fifth, Dorsal fins similar in size and shape, confluent at base. Caudal fin very small, confluent with second dorsal base. Pelvics deeply concave outwardly scalloped along anterior side of excavation; anterior lobe stout. about % as long as distance from its own origin to rear tip of pelvic which is sharply rounded. Rostra1 cartilage soft. Pectoral rays reaching nearly to tip of snout, their anterior ends close together. Claspers slender, reaching about half the distance from axils of pelvics toward first dorsal. Color of upper surface brown, the disc with a few small scattered pale spots. Pale below. The 258~mm female is more obtuse anteriorly than is the male, the maximum angle of disc in front of spiracles being 135 ; the margins straight from opposite orbits to curvature of outer corners of disc. The tail is relatively longer, its length, from center of cloaca to its tip 1.36 times as great as distance from center of cloaca to tip of snout. The upper surface of disc is densely prickled excepting at the tip of snout, along a narrow marginal band from snout to outer corners, and thence in a wider band to axils of pectorals. The tail is densely covered with prickles, as on the male; prickles arc also present on the dorsal fins and skin over eyes. The pelvics have a small patch of prickles, absent on the male. A median row of 27 thorns (including 8 empty pockets) extends from a trifle anterior to the axils of pelvics to the dorsal fin. Lower surface smooth. The upper surface is dark brown, with numerous small pale spots scattered over the disc, a few on the posterior lobes of the pelvics and on the tail. Below, the disc is plain whitish, the tail with pale brownish markings, except posteriorly. Known from the Patagonian, Falkland Islands, and South Shetland Islands region in depths of m. PSAMMOBATZS SCOBZNA ( PIIILIPPI, ) Norman ( 1937) found this to be an extremely variable species, particularly in the presence and absence of spines and in their arrangement. This genus lacks the rostra1 prolongation of the cranium. He lists in the material examined 50 males and 32 females, mm long, trawled at 26 stations, in m depths, ranging from

10 RA JIDS FROM SUB-ANTARCTiC REGION FIG. 5 Psammobatb scobina. A juvenile male, 222 mm long, from off Valparaiso, Chile S lat and from W B. brachyurops, and found the total catch long. Hart (1946) mentions this as the to be 156, the sex ratio was 67% malts, most abundant skate in this area, next to taken at 48 trawling stations,

11 1~48 ITENIXY B. BKELOW AND WILLIAM C. SCHl~OEl~El~ Study material A mature male 430 mm in total length, from off Valparaiso, Chile, on the Continental Slope, in m depth; also 3 males and 3 females, juveniles, mm long (Fig. 5), from the same locality, all taken by a commercial trawler in July Llescription of 430-mm male-proportional dimensions in per cent of total length. Disc-Extreme breadth, 60.0; length, 49.3,. Snout length-in front of orbits, 10.7; in front of mouth, Orbits-Horizontal diameter, 4.2; distance between, 4.2. Spiracles-Length, 4.4; distance between, 7.0. Mouth-Breadth, 8.9. Exposed nostrils- Distance between inner ends, 6.0. Gill openings-length: lst, 3.0; 3rd, 3.0; 5th, 2.1; distance between inner ends: Ist, 19.3; 5th, 8.4. First dorsal fin-height, 1.9; length oe base, 5.8. Second dorsal fin-height, 1.9; length oe base, 5.8. Pelvics-Anterior margin, Distance-From tip of snout to center of cloaca, 44.3; from center of cloaca to 1st dorsal, 41.3; to tip of tail, 55.7; from rear end of 2nd dorsal base to tip of tail, 2.8. In tcrspace-1st and 2nd dorsals, 0.0. Disc 1.22 times as broad as long; maximum angle in front of spiraclcs 127 ; tip of snout with a minute projection, margins of disc broadly rounded, slightly undulate opposite spiracles. Axis of greatest breadth 66% rearward from tip of snout toward axils of pectorals. Tail slender, gradually tapering to tip; the lateral folds, low down, originate about one orbit s diameter postcrior to axils of pelvics, reaching tip of tail, length of tail from center of cloaca to origin of first dorsal 0.93 times as great and to its tip 1.25 times as great as distance Erom center of cloaca to tip of snout. Three thorns at anterior margin of orbit, with two at inner posterior margin of one orbit and one thorn at the other; two thorns at inner margin of spiraclcs. A row OE six thorns along the midline from nuchal to scapular regions, with two thorns aside the most posterior two on one side but none on the other, foliowed by a row of about 42 sharp pointed thorns that originates opposite excavation of pelvic fins, ending at first dorsal, some thorns alternating in size and some paired side by side; a row each side the midrow beginning a little posterior to tip of pelvics, ending about an orbit s diameter anterior to first dorsal, the first few thorns very small, the others nearly the same size as those in the midrow. Disc with coarse prickles along outer margin from near tip of snout to outer angle; minute prickles in front of and between orbits and in a broad band along the midsection of disc and sides of tail, sparcc on posterior lobe of pelvics, present on dorsals and skin over eyes. Rest of disc smooth except for alar thorns which are very sharp, many of them in close pairs, in three rows, greatest length of rows 74 mm, and width 13 mm. Lower surface of disc and tail smooth. Snout in front of orbits 2.6 times as long as orbit, its length in front of mouth 1.9 times as great as distance between exposed nostrils. Distance between orbits equal to length of orbit. Orbit 0.95 times as long as spiracle. Nasal curtain and outer margin of nostril flap without a fringe. Jaws slightly arched. Teeth 46/46, arranged in quincunx, with ovoid or roundish bases, uppers in central area ( about 10 rows) crowded, with a low triangular cusp, bluntish (evidently worn), pointing inward, the teeth smaller in size than those in the next nine rows which have a longer and more pointed cusp directed towards corners of mouth, followed by the outward nine rows, the cusps of which are very low or lacking. The lower teeth do not vary appreciably in size. Distance between first pair of gill openings 19.3% of total length of specimen and 3.2 times as great as distance between exposed nostrils; bctwecn fifth openings 1.4 times. Length oe the gill openings, first to fourth, 3.0% and fifth, 2.1% of total length 0 E specimen. This is exceptionally great as

12 RAJIDS FROM SUB-ANTARCTIC REGION R49 compared with most other species of rajids. In the western North Atlantic Ocean, at least among 37 species of Rajidae, the greatest length of the first four gill openings for five species (R. garmani, R. laevis, R. ocellata, R. olseni, R. radiata) on which, collectively, they have proven to bc the longest, ranges from 1.8 to 23% of the total length of specimen. First and second dorsals similar in size and shape, without an intcrspacc. Caudal fin very small, its base about half as long as that of second dorsal with which it is confluent. Pelvics deeply concave outwardly, anterior lobe rather narrow, about S!/lo as long as the distance from its own origin to rear tip of pelvic, posterior lobe gently convex, its tip sharply rounded. Claspers slender, extending about S the distance rearward from axils of pclvics toward first dorsal. Rostra1 projection from front of cranium lacking, anterior part of disc supported by anterior radials of pectorals which reach nearly to tip of snout, assisted by a ligamentous band extending forward from front of cranium. The six juveniles agree closely with the 43O-mm male in proportional dimensions. The maximum angle of disc in front of spiracles ranges from 124 to 135. The disc is broadly rounded and not undulate along the anterior margin. The axis of grcatcst breadth, G&69%. Orbital thorns have not yet appeared, and the nuchals are lacking except on one specimen ( 198 mm), which has one thorn. The midrow of thorns on tail, about in number, originates, variously, from about opposite the axils of the pelvics to opposite their tips and cxtends to the first dorsal. The row is somewhat irregular, the thorns more or less alternating in size, some of them very small, none very large. The side row of tail thorns is not yet in evidence. The distribution of prickles is much the same as on the large malt although, relatively, they are not as coarse in some areas, particularly in the malar region. The nasal flap or nasal curtain, or both, have a few minute fringes on several specimens while others lack them. The teeth in the upper jaw are in 36 to 48 rows, about the same in the lower, the cusps very small on those teeth which have them, scarcely noticcablc on a male of 172 mm. The distance between the first pair of gill openings is 19.4-X7% of the total length of the spccimcns and times as great as bctweon the exposed nostrils, bctwccn the fifth openings times. The length of the gill openings, first to fourth, is % and of the fifth % of the total length of the specimens. In color, all are brown above, a few with a number of pale blotches on the disc and tail. Pale below. Known from off the coasts of Argentina, Patagonia, and Chile. REFERENCES BKELOW, II. B., AND W. C. SCIIROEDHL New genera and spccics of hatoid fishes. J. Marine Rcs., 7: , AND Fishes of the wcstcm North Atlantic. Mcm. Scars Found. Marinc Rcs., No. 1, Part 2, 588 p. l?owt,er, 11. w Notes on batoid fishes. Proc. Acad. Nat. Sci. Phila., 62: CARMAN, S The fishes (Albatross 1891 Expcd. ) Mem. Muscum Comp. Zool., Harvard Coil., 241: 431 p., 97 Pl. G~~NTEIER, A Remarks on fishes with description of new species in the British Muscum, chicfly from southern seas. Ann. Mng. Nat. Hist., Ser. 4, 17: Report on the short fishes. Rcpt. Sci. Res. Voyage H.M.S. Challenger, , Zoology, 1: Part 6, 82 p. %RT, T. J Report on trawling surveys on the Patagonian Continental Shelf ( compiled mainly from manuscripts left by the late E. R. Gunther, M. A. ). Discovery Rept., 23: JENSEN, A. S The selachians of Greenland. Mindoskr. Jap. Stcenstrup, 2( 30) : 40 p. NORMAN, J. R Coast fishes. Part II. The Patagonian region. Discovery Rept., 16: l Coast fishes, Part III. The Antarctic zone. Discovery Rept., 18: l-104. ~'IIIL~I, R. A Ueber cinigc Chilcnischc vijgcl und fischc, p Archiv fiir Naturgeschichtc, Berlin. PWZI, A. J Communication prcliminar sobrc una nueva especie dc raya de la costa atlantica argentina, Raia docllo-juradoi n. SP. Rev. Sot. Arg. Cienc. Nat., 11: p