382 Memoir Sears Foundation for Marine Research 



It would be interesting to know whether a shark of this general type, and of which 

 we received a photograph, recently taken in the Patuca River, Honduras, in fresh water 

 was this same landlocked species, or whether it was simply a leucas that had run far up- 

 stream, which we think more likely (see discussion, p. 341). 



Recent contributors who have caught sharks in Lake Nicaragua'" report them as plen- 

 tiful there as well as in the upper reaches of the San Juan River, by which the lake dis- 

 charges into the Caribbean. It is not known how far downstream its range extends in the 

 San Juan, but since there are heavy rapids in the river it seems likely that the sharks from 

 the lake and upper river are entirely landlocked. According to local reports it also runs 

 at least 40 miles up the Rio Frio, which empties into the lake close to where the latter 

 discharges via the San Juan River. Rumors of its presence in Lake Managua appear to lack 

 foundation. The fact that the specimen shown in Fig. 70 was caught from the pier after 

 only 1 5 minutes fishing is some indication of the abundance of these sharks, at San Carlos 

 at any rate."* 



Synonyms and References: 



Eulamia nicaraguensis Gill and Bransford, Proc. Acad. nat. Sci. Philad., 1877: 190 (descr., Lake Nicaragua) ; 

 Eigenmann, Proc. U.S. nat. Mus., 16, 1893: 54 (name only, San Juan R., Nicaragua) ; Marden, Nat. 

 Geogr. Mag., S6, 1944: 183 (fatalities, capture of specs., excellent photos, L. Nicaragua). 



Corcharias nicaraguensis Liitken, Vidensk. Medd. naturh. Foren. Kbh., 1879-1880: 65 (ill., meas., descr., 

 San Juan R., Nicaragua); Regan, Biol. Cent. Amer. Pisces, 1906-1908: 183 (size. Lake Nicaragua 

 and San Juan R.) ; Jordan, Evermann and Clark, Rep. U.S. Comm. Fish. (1928), 2, 1930: 16 (Lake 

 Nicaragua, San Juan R., Panama Bay, but see footnote 112, p. 380). 



Carcharhinus nicaraguensis Jordan, Proc. U.S. nat. Mus., p, 1887: 556 (name only in list. Cent. Amer.); 

 Meek, Field Mus. Publ. Zool., 7, 1907: 103 (local abund., Lake Nicaragua and San Juan R.) ; Eigen- 

 mann, Rep. Princeton Exped. Patagonia (1896— 1899), 5 (4), 1910:377 (listed) ; Smith, H. W., Biol. 

 Rev., //, 1936: 64 (fresh water) ; Norman and Fraser, Giant Fishes, 1937: 36 (confined to fresh water). 



Carcharhinus {Carcharhinus) nicaraguensis Jordan and Evermann, Rep. U.S. Comm. Fish. (1895), 1896: 216 

 (Lake Nicaragua and San Juan R.) ; Bull. U.S. nat. Mus., 47 (l), 1896: 39 (descr., Lake Nicaragua 

 and San Juan R.). 



Carcharinus milberti (in part) Garman, Mem. Harv. Mus. comp. Zool., ^6, 1913: 133 (referred to synonymy 

 of milberti); Meek and Hildebrand, Field Mus. Publ. Zool., 75, 1 923: 38 (referred to synonymy of 

 milberti); not Carcharias {Prionodon) milberti Miiller and Henle, I 84 1. 



Carcharhinus obscurus Lesueur, 1 8 1 8 



Dusky Shark, Shovelnose 



Figures 71, 72 



Study Material. One female, 996 mm., and 5 males, 993 to 1,560 mm., from the 

 vicinity of Woods Hole (Harv. Mus. Comp. Zool.); 8 males, 970 to 1,500 mm. long, 



range, but seemingly not on any factual basis; nor would it be expected there even as a stray, for Lake Nica- 

 ragua drains into the Atlantic and not into the Pacific. 



1 13. We have received several personal communications on this subject. 



114. Smith's (Science, 22, 1893: 166) statement that unnamed sharks are abundant in Lake Nicaragua no doubt 

 refers to this species. 



