Fossil Marine Vertebrates from the Blue Hill Shale Member (Middle Turonian) of the Upper Cretaceous Carlile Shale in Northeastern Nebraska

Abstract

The Blue Hill Shale Member of the Carlile Shale is a Middle Turonian (ca. 90 Ma) nearshore deposit formed during the regressive phase of the Late Cretaceous Western Interior Seaway of North America. Over 900 identifiable specimens of fossil vertebrates were recovered from a locality in northeastern Nebraska that include at least 40 taxa, comprising a minimum of 23 chondrichthyan fishes, 16 osteichthyan fishes, and one aquatic squamate reptile. The fauna includes taxa such as Meristodonoides, Cantioscyllium, Scapanorhynchus, Cretodus, Protoplatyrhina, Pseudohypolophus, and Ptychotrygon, that are commonly represented in Middle Turonian nearshore deposits of North America. The vertebrate fauna described here is composed of nearly 50% non-durophagous and 50% durophagous fishes by number of taxa. Among the nondurophagous fishes are a large carnivorous Cretodus crassidens and medium-sized scavengers Squalicorax spp., but others are primarily piscivores.