Fishes of the Western North Atlantic 477 



pis. 26, 27 (descr., ills., Matanzas, Cuba); Fowler, Monogr. Acad. nat. Sci. Philad., 7, 1945: 100, 161 

 (listed, N. Carolina, S. Carolina). 



Probable Reference: 



Rhinoptera bonasiu Fowler, Rep. N.J. Mus. (1907), 1908: 132 (ident. considered probable, Delaware Bay). 



Doubtful references: 



Rhinoptera qiiadriloba RadclifFe, Bull. U. S. Bur. Fish., J^, 1916: 279, pi. 47, fig. 4 (descr., photo, teeth, Beau- 

 fort, N. Carolina; see discuss., p. 467). 

 Rhinoptera quadriloba {bonasus) Gudger, J. Elisha Mitchell Sci. Soc, .^9, 1933 : 76, fig. 1 1 (abnormal dentition). 



Rhinoptera brasiliensis Miiller and Henle 1841 

 Figure 109 



Study Material. Three embryos, 205-209 mm wide, with open umbilical scars; 

 five specimens, 430—488 mm wide, either embryos or newborn, but with the umbilical 

 scar still visible and with one or two tail spines; head of one about 910 mm wide as 

 calculated from its breadth between the spiracles; all from Rio Grande do Sul and Rio 

 de Janeiro, Brazil; in Harvard Museum of Comparative Zoology. 



Distinctive Characters. Rhinoptera brasiliensis., if actually distinct from R. bonasus, is 

 separable from the latter only in that it has more series of teeth normally (at least nine 

 in the upper jaw in R. brasiliensis but only seven in R. bonasus) and that the teeth of 

 the median row average wider transversely relative to their lengths by the time it is 

 half-grown. But the shapes of the teeth, while noticeably divergent in extreme cases 

 {cf. Fig. 109 with 1 08 A), intergrade more or less, and the difference in the number of 

 series of teeth is not sharp cut, for at least two specimens of the genus Rhinoptera have 

 been seen with nine series above and only eight below.^^ Hence, an occasional individual 

 with eight rows in both jaws is to be expected, in which case it would not be positively 

 identifiable as either species by the number of teeth. However, it seems wise to recognize 

 the species brasiliensis, since comparison of full-grown specimens of the multidentate 

 form (when such are available) with typical bonasus may reveal additional differences 

 between the two. 



R. brasiliensis agrees with the eastern Atlantic Rhinoptera marginata and R. peli in 

 the number of series of teeth. However, all but the youngest R. brasiliensis appear to be 

 separable from both of these ^^ j^y the fact that teeth in the median series average ^-6 

 times broader (transversely) than long (anteroposteriorly) in R. brasiliensis (only about 

 three times broader than long in R. marginata or R. peli). Available information also 

 suggests that the anterior contour of the cranium is more deeply concave in R. brasiliensis 

 and in R. marginata than in R. peli (p. 468). 



Description. Proportional dimensions in per cent of extreme breadth of disc. Female, 

 430 mm broad, and male, 488 mm broad, from Rio de Janeiro, Brazil (Harv. Mus. 

 Comp. Zool., No. 534). 



52. One from Brazil in our Study Material; the other from North Carolina, pictured by RadclifFe (Bull. U. S. Bur. 

 Fish., 34, 1916: pi. 47, fig. 4) and by Gudger (J. Elisha Mitchell Sci. Soc, 4g, 1933: 76, fig. ii). 



53. If these two are actually separable one from the other; see discussion, p. 468. 



