<P> Other invertebrate groups, including rudists (reef - building clams) and inoceramids (giant relatives of modern scallops), also became extinct at the K--Pg boundary . </P> <Table> <Tr> <Td> </Td> <Td> This article needs attention from an expert in Palaeontology or Fish . The specific problem is: The paragraph on sharks and survival through the K-T event simply does not make sense . It contradicts the article on sharks, and self - contradicts . It also requires some language cleanup . WikiProject Palaeontology or WikiProject Fish may be able to help recruit an expert . (March 2017) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs attention from an expert in Palaeontology or Fish . The specific problem is: The paragraph on sharks and survival through the K-T event simply does not make sense . It contradicts the article on sharks, and self - contradicts . It also requires some language cleanup . WikiProject Palaeontology or WikiProject Fish may be able to help recruit an expert . (March 2017) </Td> </Tr> <P> There are substantial fossil records of jawed fishes across the K--Pg boundary, which provide good evidence of extinction patterns of these classes of marine vertebrates . While the deep sea realm was able to remain seemingly unaffected, there was an equal loss between the open marine apex predators and the durophagous demersal feeders on the continental shelf . </P>

What is the k-t boundary event most known for