A review of the comparative morphology and systematics of Utah Lake suckers (Catostomidae)

Abstract

Utah Lake, Utah, U.S.A. harbours an endemic catostomid fish, the June sucker Chasmistes liorus, that is recognized as being endangered. Since 1981, post-1935 representatives of the June sucker have generally been considered to be examples of a self-propagating hybrid. Utah Lake has contained another endemic catostomid, the webug sucker Chasmistes fecundus that was regarded as a true species until 1981 when it was judged to be an extirpated sterile hybrid. Since then, fisheries biologists have not attempted to identify it. This review makes a comparative examination of the published descriptions of the internal and external anatomy of these two species, plus the third catostomid of Utah Lake, the Utah sucker Catostomus ardens. The Utah sucker purportedly crossed with a form of the June sucker that has supposedly since been expunged, to produce hybrids. On the basis of comparative morphology and the consideration of temporal changes in the habitat and piscifauna of Utah Lake, the authenticity of supposed hybridism in the webug sucker, and in the contemporary June sucker, is analysed. The conclusion is reached that there is insufficient evidence to deem these taxa hybrids, or the webug sucker, extinct.