Squalodontidae closely related to the South Asian river dolphin ("Platanista gangetica"). The genus "Squalodon" was named by French naturalist Jean-Pierre Sylvestre de Grateloup in 1840 based on a jaw fragment he thought belonged to a reptile. Fossils discovered later, nevertheless, showed that this was a toothed whale. In extant odontocetes, however, the dentition is atavistic with all teeth reduced to simple, undifferentiated conical shapes. In squalodonts the teeth resemble those of the archaic whales, Archaeoceti, with conical incisors anteriorly and low-crowned, serrated teeth posteriorly. Squalodontidae Squalodontidae or the shark-toothed dolphins is an extinct family of large toothed whales who had long
Endangered species suggests a positive relationship between human activity and species endangerment. Under the Endangered Species Act of 1973 in the United States, species may be listed as "endangered" or "threatened". The Salt Creek tiger beetle ("Cicindela nevadica lincolniana") is an example of an endangered subspecies protected under the ESA. The US Fish and Wildlife Service as well as the National Marine Fisheries Service are held responsible for classifying and protecting endangered species, and adding a particular species to the list can be a long, controversial process (Wilcove & Master, 2008, p. 414). Some endangered species laws are controversial. Typical areas of