A new specimen of Parahesperornis (Ayes: Hesperornithiformes) from the Smoky Hill Chalk (Early Campanian) of western Kansas

摘要

Despite the abundance of hesperornithiform fossils from the Western Interior of North America, particularly the Niobrara Chalk of Kansas, few specimens are known of Parahesperornis, a toothed, foot-propelled diving bird somewhat smaller than Hesperornis.Numerous specimens of three species of Hesperornis as well as those of Baptornis advenus are known from the Smoky Hill Chalk of western Kansas, but only two specimens of Parahesperornis have been collected to date. This paper presents a new specimen of Parahesperornis and a detailed description of the tarsometatarsus of this genus. Minor differences in morphology of the isolated tarsometatarsus presented here prevent its inclusion in Parahesperornis alexi, however these differences are not sufficient to warrant the designation of a new taxon at this time.