Fishes of the Western North Atlantic 363 



Dasyatis geijskesi Boeseman 1 948 

 Figure 85 

 Study Material. None. 



Distinctive Characters. This newly described species*"- differs noticeably from all 

 other known dasyatid Rays of the Atlantic in shape of disc with narrowly projecting 

 snout, and pelvic fins with long anterior margins and narrowly pointed and somewhat 

 falcate outer corners. 



Description. ^°^ Proportional dimensions in per cent of extreme breadth. 

 Disc: length 103.0. 



Snout length: in front of orbits 42.7; in front of mouth 41.2. 

 Orbits: horizontal diameter 1.8; distance between 10. o. 

 Spiracles: length 5.2; distance between 14.7. 

 Mouth: breadth 8.5. 



Exposed nostrils: distance between inner ends 11.8. 



Gill openings: longest 2.8; distance between inner ends, ist 14.7; 5th 13.0. 

 Pelvics: anterior margin 35.3. 

 Distance: from tip of snout to center of cloaca 92.5. 



Disc about as broad as long; anterior margins deeply concave, the snout pro- 

 jecting conspicuously as shown in Fig. 85, slightly blunted at tip; outer corners 

 broadly rounded, outer posterior margins moderately and evenly convex, but posterior 

 corners well rounded; inner margins weakly convex and somewhat excavate at axils. 

 Axis of greatest breadth about 48 "/o of distance back from tip of snout toward level 

 of axils of pectorals. Tail slender, whip-like, somewhat flattened dorsoventrally in 

 advance of tail spines but more rounded posteriorly, with a low keel on either side; 

 upper surface of tail with a low keel originating a little behind tip of second spine, 

 gradually disappearing rearward; lower surface of tail (on juvenile male) with a shallow 

 median groove along anterior part and a narrow cutaneous fold extending rearward 

 for a distance about Vs (22 "/o) as great as length of disc from a little anterior to insertion 

 of spine, its maximum width about Vs as great as longitudinal diameter of eye; dorsal 

 keel and ventral fold perhaps becoming larger with growth; length of tail (somewhat 

 mutilated) from center of cloaca about 2.35 times as great as distance from center of 

 cloaca to tip of snout and almost 2.1 times as great as length of disc. 



Two tail spines (on only specimen known) sharp-tipped and laterally serrate, the 

 anterior spine about twice as long as eye, the posterior spine about 4.5 times the eye; 

 the longer spine about 8 "/o as wide as long. 



Central belt on upper surface of disc and on upper surface of tail posterior to 

 spines rough with small low tubercles, rounded on disc but more conical and with 

 radiate bases on tail; a median row of larger tubercles from nuchal region to a little 

 anterior to tail spines, interrupted on posterior part of disc, the tubercles widely spaced 

 on tail; median tubercles with narrow flat-topped crest rising from front to rear, more 



102. Known only from the original account (see Reference, p. 364). 103. After Boeseman. 



