Fishes of the IVestern North Atlantic 429 



Body much compressed, its ventral outline strongly convex, forming a pronounced 

 arc, its greatest depth over basal half of pectoral, 1.8-2.0 in SL. Caudal peduncle 

 short, its depth 3.0 in head. 



Ventral scutes prominent, especially the posterior ones. A median series of 5 

 spines between occiput and origin of dorsal. 



Head 3.65-4.0 in SL. Snout shorter than eye, 3.5 in head. Eye 2.5 in head. 

 Interorbital half of width of eye. Mouth almost vertical. Maxillary extending 

 below anterior margin of eye, 2.5 in head. Mandible projecting, extending nearly into 

 dorsal outline of head. Gill rakers slender, about 2.25 times in diameter of eye, 20-23 

 on lower limb. 



Dorsal fin high anteriorly, its longest rays reaching far beyond tip of last ray 

 if deflexed, nearly as long as head, its origin much nearer to margin of snout than to 

 base of caudal. Caudal fin well forked, the lobes a little shorter than head. Anal long, 

 its origin under or just behind last rays of dorsal, a little less than 0.5 of SL. Pectoral 

 a little shorter than head. 



Color. After Fowler: "Color in alcohol with back pale brown and under surfaces 

 bright shining silvery white. Iris silvery white. Back and occiput with scattered dark 

 to blackish dots. Dorsal and caudal yellowish buff basally, pale gray terminally. Other 

 fins dull buff." 



Size. A maximum length of only 1 10 mm (4.4 in.) has been reported. 



Range. Coast of the Guianas to Brazil, ascending streams; reported from the 

 Ucayali River Basin in the upper Amazon system, Peru. 



Synonyms and References: 



/'m/r^^dx/^rCuvier, Regne Anim., ed. \,2, 1817: I76and^:pl. 10, fig. 3 (diagn. of genus and species combined; 

 no specific name given; type local. "Seas of America"); Cuvier, Regne Anim., ed. 2, J, 1830: pi. 12, 

 fig. 3 (no specific name on plate, but includ. in 1829 text; see under P. cayanus below). 



Pristigaster cayanus Cuvier, Regne Anim., ed. 2, 2, 1829: 321 {two spp. referred to; name cayanus provided 

 for Amer. species figured in 1817; type local, fixed by specific name as Cayenne, French Guiana; fig. on 

 1830 plate of ed. 2 Regne Anim. ident. to that in ed. i); Cuvier and V'alenciennes, Hist. Nat. Poiss., 

 20, 1847: 334, pi. 597 (descr., discus.); Giinther, Cat. Fish. Brit. Mus., 7, 1868: 463 (synon., descr., 

 range); Jordan and Evermann, Bull. U. S. nat. Mus., 47 (i), 1896: 438 (descr. after Cuvier and Valen- 

 ciennes, synon.); Starks, Stanf. Univ. Publ., 1913: 9 (Madeira R., Brazil, 400 miles above mouth); 

 Norman, Ann. Mag. nat. Hist., (9) 11, 1923: 14 (synon., descr., range); Jordan, Evermann, and Clark, 

 Rep. U. S. Comm. Fish. (1928), 2, 1930: 45 (range, synon.); von Ihering, Rev. Indust. Anim., i (3), 

 1930: 230 (ref, diagn.); von Ihering, Die. Anim. Brasil, 1940: 716 (habitat, notes); Eigenmann and 

 Allen, Fish. West. S. Amer., 1942: 333 (Peruvian Amazon). 



Pristigaster martii Agassiz, in Spix and Agassiz, Genera Species Pise. Brazil., 1829: 55, pi. 24a (orig. descr.; 

 type local, mouth of Amazon); Cuvier and Valenciennes, Hist. Nat. Poiss., 20, 1847: 337 (presumed 

 differences from P. cayanus; rec. for the mouth of Amazon); Castelnau, Anim. Nouv. Rates Amer. 

 Bud, Poiss., 1855: 57 (Amazon); Fowler, Proc. Acad. nat. Sci. Philad., gi, 1940: 221, fig. 2 (Rio 

 Ucayali, Peruvian Amazon, synon., descr.); Campos, Arqu. Zool. estad. Sao Paulo (1941), J (7), 

 1942: 187, fig. 2 (synon., descr., geogr. distr.); Fowler, Arqu. Zool. estad. Sao Paulo, 6, 1948: 16, 

 fig. 6 (synon.). 



Pristigaster americanus Guerin-MeneviUe, Iconogr. R^gne Anim. Cuvier, Poiss., 1829-1844: 33, pi. 57, fig. 3 

 (type local, coast of S. Amer. in Atlantic). 



Pristigaster phaeton Cuvier and Valenciennes, Hist. Nat. Poiss., 20, 1847: 338 (orig. descr., type local. Amazon); 



