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Hemisyntrachelus; Temporal range: Late Miocene-Quaternary; ~5.333–1.806 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Hemisyntrachelus cortesii skull
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Infraorder:	Cetacea
Family:	Delphinidae
Subfamily:	Orcininae
Genus:	†Hemisyntrachelus; Brandt 1873
Species
	H. cortesii Fischer 1829; H. oligodon Pilleri and Siber 1989; H. pisanus Biannuci 1996;
Synonyms
	Delphinus cortesii

Hemisyntrachelus is an extinct genus of cetacean.^[1]^[2]^[3]

Fossil records

This genus is known in the fossil records from the latest Miocene to the Quaternary (age range: from 5.332 to 1.806 million years ago). Fossils are found in the marine strata of Italy, the Netherlands, the Bahía Inglesa Formation of the Caldera Basin, Chile and in the fossiliferous Pisco Formation of Peru.^[2]^[3]

Species

The following species have thus far been classified as belonging to this genus:.^[2]^[3]

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).^[3] Its fossil skeleton reaches a length of about 3 metres (9.8 ft) and it has been found only in La Torrazza, Italy. This species shows intermediate characters between the bottlenose dolphin and the killer whale. 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 Pisco Formation of Peru.^[3]

Hemisyntrachelus pisanus could reach a length of about 5 metres (16 ft). It was widespread in the Mediterranea Sea during the Miocene. Fossils have been found only in Orciano, which is in a Piacenzian coastal claystone in Italy.

Gallery

Skull cast of Hemisyntrachelus cortesii
Skull cast of Hemisyntrachelus pisanus

References

^ Bianucci, G.; Vaiani, S. C.; Casati, S. (2009). "A new delphinid record (Odontoceti, Cetacea) from the Early Pliocene of Tuscany (Central Italy): Systematics and biostratigraphic considerations". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 254 (3): 275. doi:10.1127/0077-7749/2009/0018.
^ ^a ^b ^c Global Biodiversity Information Facility article on Hemisyntrachelus, accessed 11/10/13
^ ^a ^b ^c ^d ^e Hemisyntrachelus at Fossilworks.org