Allodelphis
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''Allodelphis'' is an
extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
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whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...
belonging to Allodelphinidae found in marine deposits of the eastern North Pacific.


Description

''Allodelphis'' has a very elongated rostrum and a polydont, heterodont dentition. It differs from '' Ninjadelphis'' and '' Zarhinocetus'' in the following characters: wider dorsal opening of mesorostral canal anterior to dorsal nares, posterior part of rostrum anterior to dorsal nares not depressed, posterior ends of premaxillae less irregular and digitated, posterior ends of premaxillae extending posteriorly beyond level of posterior margins of corresponding nasal bones, nasal bones elevated anteriorly rather than tilting anteroventrally into posterior part of dorsal nares, nasal bones expanded in width anteriorly rather than narrow anteriorly, nasal bones not fused to each other at midline or to underlying frontal bones, instead having margins defined clearly by sutures, nasal bones and dorsal exposures of frontal bones at cranial vertex symmetrical, with mid-line sutures on mid-sagittal plane rather than skewed asymmetrically to left side, right and left halves of nuchal crest symmetrical and having approximately equal widths and curvatures, and nuchal crest nearly straight transversely rather than curved anteriorly near cranial vertex; tympanic bulla with less inflated outer lip, and smaller and more posteriorly directed sigmoid process; atlas vertebra having dorsal transverse process tapered and not expanded dorsoventrally.Toshiyuki Kimura and Lawrence G. Barnes (2016). "New Miocene fossil Allodelphinidae (Cetacea, Odontoceti, Platanistoidea) from the North Pacific Ocean". Bulletin of the Gunma Museum of Natural History 20: 1–58.


Taxonomy

Two species are currently recognized, ''A. pratti'' and ''A. woodburnei''. The latter species is found in younger (Early Miocene, Aquitanian) deposits than ''A. pratti'', which is found in the late Oligocene
Jewett Sand Formation The Jewett Sand Formation is a Formation (geology), geologic formation in California, USA. It preserves fossils dating back to the Miocene Epoch (geology), Epoch of the Neogene Period (geology), period. Vertebrates Cartilaginous fishes Sharks ...
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Kern County Kern County is a county (United States), county located in the U.S. state of California. As of the 2020 United States census, 2020 census, the population was 909,235. Its county seat is Bakersfield, California, Bakersfield. Kern County compris ...
, California.L. G. Barnes and R. E. Reynolds. 2009. A new species of early Miocene allodelphinid dolphin (Cetacea, Odontoceti, Platanistoidea) from Cajon Pass, Southern California, U.S.A. Museum of Northern Arizona Bulletin 65:483-507.


Biology

The nature of the sediments in which ''Allodelphis'' has been found denotes a neritic environment for the genus. The advanced degree of telescoping in the cranium shows that it could track prey using echolocation.


References

Allodelphinidae Oligocene cetaceans Miocene cetaceans Prehistoric cetacean genera Fossil taxa described in 1935 {{paleo-whale-stub