﻿REVIEW OF GENUS DOROSOMA — MILLER 401 



C.N.H.M. No. 5925: 6 young from Lake Managua. 



C.N.II.IM. No. 5926: G specimens, 53 to 137 mm. long, from Lake Managua. 



C.N.H.M. No. 5927: 6 specimens, 110 to 125 mm. long, from Laguna San 

 Francisco. 



C.N.H.M. No. 5928: 5 specimens, 123 to 142 mm. long, from Laguna Jenfcero. 



C.N.H.M. Nos. 14631-36: 6 specimens, 135 to 162 mm. long, from Laguna 

 Jenicero. 



U.S.N. M. No. 78100: 2 specimens, 88 and 171 mm. long, from Nicaragua. 



U.S.N.M. No. 16882: 2 young in poor condition, 41 and 68 mm. long, col- 

 lected by J. F. Bransford in Lake Nicaragua in March, 1876. 



U.S.N.M. No. 22138: 3 adults, 145 to 186 mm. long, collected by Bransford 

 in Nicaragua in 1877. 



Range. — Kno\vn only from the basins of Lakes Managua and 

 Nicaragua in Nicaragua. 



DOROSOMA SMITHI Hubbs and Miller 



Dorosoma sm'dhi Hubbs and Miller, 1941, pp. 232-238, fig. 1 (original descrip- 

 tion; type locality, Rfo Piaxtla near Piaxtla, Sinaloa, Mexico). 



This is the only species of Dorosoma known from the Pacific drain- 

 age, and it has been taken thus far only in northwestern Mexico. 

 Since D. smithi was described from only five type and three nontype 

 specimens, its range of variation was imperfectly known. The ex- 

 amination of 177 additional specimens, along with renewed study 

 of the original series, has brought to light new characters that further 

 distinguish smithi and has eliminated most of the described differences 

 beteen the types and the three variants. 



All the additional series of smithi were generously collected by my 

 father, the late Ralph G. Miller, from the state of Sinaloa: in the Rio del 

 Fuerte, the Rio Sinaloa Basin, and in the Rio de Mocorito. These 

 three streams lie between the type locality, Rio Piaxtla, also in Sinaloa, 

 and Rio Muerto, Sonora, where the variants discussed by Hubbs and 

 Miller (1941, pp. 237-238) were taken. The new material agrees 

 well with the original description. 



Diagnosis. — A Dorosoma with 43 to 47 (usually 44 or 45) vertebrae, 

 71 to 79 lateral scales, 50 to 60 scales around the body, 28 to 31 

 scales around the caudal peduncle, 11 or 12 (rarely 9, 10, or 13) dorsal 

 rays, 22 to 29 (24 to 27) anal rays, usually 17+11 ventral scutes, 

 and with a short dorsal filament. 



Relationships. — D. smithi is distinguished most significantly from the 

 other members of the genus by the much fewer vertebrae, the reduced 

 number of anal rays, and the greater number of scales around the 

 caudal peduncle and around the body (tables 2^). In having a 

 short dorsal filament it closely approaches D. chavesi (table 5) and 

 differs sharply from both D. cepedianum and D. anale. The number 

 of prepelvic scutes, usually 17 and commonly 16, is also similar to 

 that of chavesi, and the fewer anal rays is a further point of resemblance 

 between these two species. 



