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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 ...
Two endemic, distinctive types of short-finned pilot whale, Tappanaga (or Shiogondou) the larger, northern type and Magondou the smaller, southern type, can be found along the Japanese archipelago where distributions of these two types mostly do not overlap by the oceanic front border around the easternmost point of Honshu.
The two parvorders, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have diverged around thirty-four million years ago. [13] Baleen whales have bristles made of keratin instead of teeth. The bristles filter krill and other small invertebrates from seawater. Grey whales feed on bottom-dwelling mollusks.
The family Balaenidae, the right whales, contains two genera and four species. All right whales have no ventral grooves; a distinctive head shape with a strongly arched, narrow rostrum, bowed lower jaw; lower lips that enfold the sides and front of the rostrum; and long, narrow, elastic baleen plates (up to nine times longer than wide) with fine baleen fringes.
This dolphin is found mainly in the Alboran Sea and the north-western Mediterranean [13] [14] [17] [34] where its population is estimated at between 3,000 and 5,000 individuals. [2] The other pilot whale species, the long-finned pilot whale (G. macrorhynchus), seems to have been seen at least once in the Mediterranean, probably as a stray group ...
The first spade-toothed whale bones were found in 1872 on New Zealand’s Pitt Island. Another discovery was made at an offshore island in the 1950s, and the bones of a third were found on Chile ...
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.
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 ...