''Hemisyntrachelus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

cetacean Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

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Fossil records

This genus is known in the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

s from the latest Miocene to the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...

(age range: from 5.332 to 1.806 million years ago). Fossils are found in the marine strata of

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

, the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

, the

Bahía Inglesa Formation Caldera Basin ( es, Cuenca de Caldera) is a sedimentary basin located in the coast of northern Chile west of Copiapó. The basin has a fill of marine sediments of Late Cenozoic age. With a north-south extension of and an east-west width of the ...

of the Caldera Basin,

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

and in the fossiliferous

Pisco Formation The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica, Peru, Ica and Arequipa. The approximately thick formation was deposited in the Pisco Basin, spanning an age from the Miocene, Middle Miocene up to ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

Species

The following species have thus far been classified as belonging to this genus:.Global Biodiversity Information Facility article on ''Hemisyntrachelus''
accessed 11/10/13 * ''Hemisyntrachelus cortesii'' Fischer 1829 * ''Hemisyntrachelus oligodon'' Pilleri and Siber 1989 * ''Hemisyntrachelus pisanus'' Biannuci 1996

Description

''Hemisyntrachelus cortesii'' lived about three million years ago (from 3.6 to 2.588 mya). Its fossil skeleton reaches a length of about and it has been found only in La Torrazza, Italy. This species shows intermediate characters between the

bottlenose dolphin Bottlenose dolphins are aquatic mammals in the genus ''Tursiops.'' They are common, cosmopolitan members of the family Delphinidae, the family of oceanic dolphins. Molecular studies show the genus definitively contains two species: the common ...

and the

killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pa ...

. It fed on large fishes and squids. ''Hemisyntrachelus oligodon'' lived from 7.246 to 5.332 million years ago. Fossils have been found only in the

of Peru. ''Hemisyntrachelus pisanus'' could reach a length of about . It was widespread in the Mediterranea Sea during the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

. Fossils have been found only in Orciano, which is in a Piacenzian coastal claystone in Italy.

Gallery

File: HemisyntrachelusCortesii.JPG, Skull cast of ''Hemisyntrachelus cortesii'' File: Hemisyntrachelidae - Hemisyntrachelus pisanus.JPG, Skull cast of ''Hemisyntrachelus pisanus''

Fossil records

Species

Description

Gallery

References

Further reading