Arktocara ("Platanista gangetica") which inhabits the tropics, making it its closest living relative. Allodelphinidae also included the genera "Allodelphis", "Goedertius", "Ninjadelphis", and "Zarhinocetus". Its discovery further reinforces the theory that the Platanistoidea river dolphins originated in the oceans. Of the characteristics it shared with other platanistoids was a cylindrical projection of the periotic bone in the ear, deeply grooved rostral sutures on the beak, the widening of the cranium, a depression on the roof of the orbit in the eye socket, a smaller exposed palatine bone in the roof of the mouth, an elongated and convex spine in the tympanic bulla
Endangered Species Act of 1973 habitat protection and recovery goals, requiring the identification and protection of all lands, water and air necessary to recover endangered species. To determine what exactly is critical habitat, the needs of open space for individual and population growth, food, water, light or other nutritional requirements, breeding sites, seed germination and dispersal needs, and lack of disturbances are considered. As habitat loss is the primary threat to most imperiled species, the Endangered Species Act of 1973 allowed the Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) to designate specific areas as protected "critical habitat" zones. In 1978, Congress