Protodobenus japonicus (lat.) - a species of extinct marine mammals from the family Walrus order of prey . The only species of the genus Protodobenus . Its fossils were found in Niigata Prefecture ( Japan ), in the Lower Pliocene sediments (5.0-4.9 million years ago) [1] .
† Protodobenus japonicus | ||||||||||||||||||||
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 Protodobenus japonicus , head reconstruction | ||||||||||||||||||||
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| Protodobenus japonicus Horikawa, 1995 |
Content
- 1 Appearance and structure
- 2 Lifestyle and nutrition
- 3 Origin and family ties
- 4 notes
Appearance and structure
The structure of the skull of Protodobenus japonicus is similar to the modern walrus , but it is much more primitive, especially in terms of the structure of teeth and jaws [1] .
Lifestyle & Nutrition
The structure of the skull, especially the palate and lower jaw, suggests that Protodobenus japonicus had a morphological pre-adaptation to feeding by sucking mollusks from shells (a method of feeding modern walruses), but it could hardly be fed this way [1] .
Origin and kinship
Protodobenus japonicus comes from Imagotariinae . It is similar to such primitive walrus fossils as Ontocetus emmonsi from the western Atlantic Ocean and Aivukus cedrosensis from California, and has some common features with them, as well as significant differences from them. It is possible that the modern genus Walrus originated from Protodobenus japonicus [1] .
Notes
- ↑ 1 2 3 4 Hideo Horikawa. A primitive odobenine walrus of Early Pliocene age from Japan // Island Arc. - 1994. - Vol. 3 , iss. 4 . - DOI : 10.1111 / j.1440-1738.1994.tb00118.x .