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The toothed whales (also called odontocetes, systematic name Odontoceti) are a clade of cetaceans that includes dolphins, porpoises, and all other whales with teeth, such as beaked whales and the sperm whales. 73 species of toothed whales are described. They are one of two living groups of cetaceans, the other being the baleen whales (Mysticeti ...
Whales emerged about 52 million years ago in the Tethys Ocean (between present-day India and Asia). It was a warm, fertile shallow sea very much like the one which covered southeastern United States 40 million years ago when whales (Georgiacetus & Carolinacetus) were already present in America. There are two schools of thought on how they got ...
Another similar feature was the composition of the teeth, which contained mostly calcium phosphate which is needed for eating and drinking by aquatic animals, though, unlike modern day toothed whales, they had a heterodont (more than one tooth morphology) dentition as opposed to a homodont (one tooth morphology present) dentition. [62]
Archaeoceti ("ancient whales"), or Zeuglodontes in older literature, is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene 1] Representing the earliest cetacean radiation , they include the initial amphibious stages in cetacean evolution , thus are the ancestors of both modern cetacean suborders ...
A beaked whale is any of at least 22 species of whale in the family Ziphiidae. Several species have only been described in the last two decades. Six genera have been identified. They possess a unique feeding mechanism among cetaceans known as suction feeding. They are characterized by having a lower jaw that extends at least to the tip of the ...
Ankylorhiza was about 4.8 meters (16 ft) long, with a long, robust skull bearing conical teeth that were angled forwards at the tip of the snout. Ankylorhiza is the largest known Oligocene toothed whale and is one of the most completely known early members of this group, with characteristics intermediate between basal and derived cetaceans. The ...
Millions of prehistoric marine fossils were discovered beneath a California high school over the course of a multi-year construction project. The relics recovered at San Pedro High School included ...
Odontocetes, such as the sperm whale, possess teeth with cementum cells overlying dentine cells. Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. Only in larger whales, where the cementum is worn away on the tip of the tooth, does enamel show.