Osteology and morphology of the genera Cristivomer and Salvelinus and their relationships with other Salmonidae.

Abstract

The aim of this study, which is mainly osteological, is to clarify the status of the genera Cristivomer and Salvelinus. A morphometric and meristic study in conjunction with osteology was used to assess their phylogenetic relationships with other genera of Salmonidae. About 390 specimens of adult and adolescent fish and 268 eggs and fry were examined. Presently, seven genera are recognized in Salmonidae. The genus Cristivomer is separated from Salvelinus because of the shape of the supraethmoid, supramaxilla, subopercle, vomer, lingual plate, and caudal fin, and also the high number of pyloric caeca, presence of pearl organs, and breeding behaviour of the former. In the genus Salvelinus, S. alpinus (including various forms), S. malma, and S. fontinalis are distinguished. S. alpinus oquassa, previously known as S. marstoni, is considered a subspecies of S. alpinus. The two previously designated species S. oquassa and S. aureolus are synonymized with S. a. oquassa. S. timagamiensis is reduced to a sub-species of S. fontinalis. The genus Salmothymus is maintained. The genus Cristivomer is more generalized than Salvelinus. The species S. malma is intermediate between S. alpinus and S. fontinalis. For the first time a detailed osteological study of C. namaycush and several forms of Salvelinus is undertaken, and their relationships assessed.