No abstract

No abstract

Cardabiodon ricki and Cardabiodon venator were large lamniform sharks with a patchy but global distribution in the Cenomanian

No abstract

No abstract

No abstract

The latest early Campanian archipelago deposits of the Kristianstad Basin, southern Sweden, yield one of the most diverse Cretaceous chondrichthyan faunas collected from a narrow stratigraphical interval. Building on previous descriptions of various selachians, squatiniform and synechodontiform sharks are added to the faunal list. Squatinidae is represented by Squatina (Squatina) lundegreni sp. nov. and Squatina (Squatina) fortemordeo sp. nov. The poorly preserved type specimens of the nominal Squatina hassei from the Maastrichtian of The Netherlands were recently regarded conspecific with better preserved Santonian–Maastrichtian teeth of Squatina (Cretascyllium) from the Anglo-Paris Basin. This appears to have been based largely on the assumption that the nominal S. hassei was the only Squatina present in NW Europe during the Santonian–Maastrichtian. The Swedish material indicates a greater diversity of squatinoids, and the nominal S. hassei is here regarded as a nomen dubium of uncertain subgeneric affinity. Two types of synechodontid teeth with a tall central cusp co-occur in the Campanian of the Kristianstad Basin. Based on articulated jaws of the markedly dignathic S. dubrisiensis from the Cenomanian of England, the two morphs are regarded as upper and lower anterior teeth of the single species S. filipi sp. nov.

A euselachian assemblage was recovered from the middle Cenomanian Dunvegan Formation situated in northwestern Alberta. This assemblage is the most northern described within the Western Interior Seaway and provides an important insight into the euselachian faunal diversity of this little-known region of the seaway. Despite its high paleolatitude, the assemblage contains a number of elasmobranch taxa, including Hybodus , Squalicorax , Archaeolamna , Cretodus , Dallasiella , and Cretoxyrhina . The Dunvegan assemblage also contains the first known reports from Canada of the odontaspid shark Johnlongia parvidens , the cretoxyrhinid shark Protolamna carteri , and the ray Pseudohypolophus mcnultyi . This assemblage extends the northern geographical range of all taxa. Preliminary comparisons with other middle Cenomanian Western Interior Seaway assemblages show that the core composition of the Dunvegan assemblage is remarkably similar to that of other time-equivalent assemblages; however, conspicuously absent are species that are exceedingly common in other localities situated farther south. We suggest that absence of these taxa from the Dunvegan localities may be caused by a temperature intolerance associated with latitude and sea-water circulation patterns, or by an inability to inhabit environments that exhibit salinity variation.