A fossil clupeomorph fish from the Albian of the Northwest Territories of Canada, with notes on cladistic relationships of clupeomorphs



A primitive clupeomorph, Erichalcis arctagen. et sp. nov. is described from the Albian of Northwest Territories, Canada. Erichalcis is uniquely specialized among clupeomorphs in the presence of enlarged lateral line scales and in the structure of the caudal skeleton. Erichalcis is classified as Clupeiformes incertae sedis. The two recognized suborders, Clupeoidei and Denticipitoidei are examined with respect to primitive and derived character states. It is concluded that the clupeoids and denticipitoids are divergently specialized in details of the union between the supraorbital and infraorbital sensory canals and the recessus lateralis. It is further suggested that the reduction in size and the posterior shift of the dermosphenotic in clupeoids is correlated with an upper division of the levator arcus palatini muscle and an antero-dorsal process on the hyomandibular. Cladistic relationships of some Cretaceous clupeomorphs are proposed and it is suggested that Diplomystus brevissimus Cope not be included in the Clupeoidei.