THE DISCOVERY OF HETEROTIDINAE (TELEOSTEI, OSTEOGLOSSIDAE) FROM THE PALEOCENE PASKAPOO FORMATION OF ALBERTA, CANADA

A new fossil genus of Osteoglossidae, named dagger Joffrichthys gen. n ov., is described based mainly on three articulated specimens from the Paskapoo Formation of central Alberta, Canada. This discovery suggest s the occurrence of Heterotidinae in the Paleocene of western North Am erica. The inclusion of dagger Joffrichthys gen. nov. in the Heterotid inae is supported by at least four synapomorphies: maxilla posteriorly lying on dentary part of lower jaw, horizontal arm of preopercle abou t as long as vertical arm, a large, irregularly wide, and trapezoidal io2, and approximately equal-sized dorsal and anal fins. The presumed dagger Sinoglossus-Scleropages-Osteoglossum relationship is not suppor ted. This paper recognizes a Heterotidinae relationship of dagger Sino glossus based on shared derived character slates. Three features (io1 used with antorbital. a typical ''cheek wall'' formed by io1 to io3 an d covering all the area below the orbit from the antorbital to the ant erior edge of the preopercle, and reticulate scales) even suggest that the eastern Asian Eocene-Oligocene dagger Sinoglossus is probably sis ter to the clade consisting of Heterotis and Arapaina. Two Late Jurass ic and/or Early Cretaceous eastern Asian teleosts (dagger Huashia and dagger Kuntulunia) and one mid-Cretaceous South American primitive ost eoglosso-morph (dagger Laeliichthys) might have some relationship with the ancestral lineages of Heterotidinae. However, evidence remains in conclusive about the early evolution of Heterotidinae.