Genus Sahelinus Richardson 1836 



By 



Henry B. Bigelow 



Museum of Comparative Zoo/ogy 

 Harvard University 



Sahelinus Richardson, Fauna Boreal.-Amer., 3, 1836: i6g; first use in the singular (by implication) of the 

 group name Salmones salvelines of Nilsson, Prod. Ichthyol. Scand., 1832: 7; type species, Salmo sahelinus 

 Linnaeus, Syst. Nat., ed. 10, j, 1758: 309, Austria, designated by Jordan, Genera Fish., 2, 1919: 186. 



Generic Synonyms: 



Salmo (in part) Linnaeus, Syst. Nat., ed. 10, j, 1758, for S. alpinus Linnaeus 1758 : 309, Lapland, .Alpine lakes 

 in England; S. sahelinus Linnaeus, 1758: 309, Austria; S. salmarinus Linnaeus, 1758: 310, "Habitat 

 tridente in fluviis frigidis"; and S.umbla Linnaeus, 1758: 310, Switzerland.^ 



Baione, DeKay, Zool. N. Y., Fishes, 4, 184.2: 244; rj-pe species, B.fontinalis DeKay 1842; Rockland County, 

 New York. 



Umbla, von Rapp, Jheft. Ver. ^'aterl. Naturk. Wijrttemberg (1854), 10, 1856: 171; t)'pe species, Salmo umbla 

 Linnaeus, Syst. Nat., ed. 10, j", 1758: 310; Lakes of Switzerland and Italy. 



Not Cristivomer Gill and Jordan in Jordan, Manual Vert, north. U. S., ed. 2, 1878: 356, 359; type species, 

 Salmo namaycush Walbaum, P. Artedi Genera Pise, Ichthyol., Emend., 3, 1792: 68, by ref. to "the 

 Namaycush," Pennant, Arctic Zool., I, Introd., 1784; cxci; lakes far inland from Hudson Bay. 



Characters. Essentially as in the genus Salmo, but with: Scales very small, 

 scarcely visible — at least 195 rows and commonly 200 or more (120—130 in Salmd)\ 

 Teeth lacking on shaft ot vomerine bone along midline of roof of mouth (one or two 

 more or less complete rows in the young of all species of Salmo, persisting throughout 

 life in some); the teeth on premaxillaries usually forming a continuous series around 

 front of mouth (for exception, see Fig. 127). Caudal fin only moderately concave. 

 Bone above vomer (Ethmoid of Kendall, Mesethmoid of Regan, Proethmoid of Starks) 

 more than 38 "/q as wide as long. Frontal area of skull not flat, usually with a median 

 longitudinal ridge. Not more than 50 Pyloric caeca. 



Sexual Dimorphism. Normally, in the mature male the head is noticeably larger 

 than in the female, as is the mouth, the teeth are somewhat larger, and the pectoral 

 and pelvic fins are somewhat longer. In the male at spawning time the lower jaw be- 

 comes slightly hooked, as in Fig. 124 (less so than in the salmon), a thick mucous 

 layer develops, nearly or quite concealing the scales, and the colors intensify, especially 

 the reddish hues, with the white margins of the pectoral and pelvic fins standing out 

 more conspicuously. These seasonal characters disappear soon after spawning has been 

 completed (45: 85; 62: 7; 9: 8). 



Remarks. The restriction of the genus Sahelinus to species having a nearly truncated 



I. Salmo lacustris Linnaeus, 1758: 309, appears to have included more than one species. For an early discussion, see 

 Heckel {31: 353, pi. 7, figs. 4, 5). 



