''Aegicetus'' 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 ...

protocetid Protocetidae, the protocetids, form a diverse and heterogeneous group of extinct cetaceans known from Asia, Europe, Africa, South America, and North America. Description There were many genera, and some of these are very well known (e.g., ''Ro ...

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

based on a partial skull with much of an associated postcranial skeleton discovered in

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

.Philip D. Gingerich, Mohammed Sameh M. Antar und Iyad S. Zalmot: "''Aegicetus gehennae'', a new late Eocene protocetid (Cetacea, Archaeoceti) from Wadi Al Hitan, Egypt, and the transition to tail-powered swimming in whales". ''PLoS ONE'' 14(12): e0225391 doi:10.1371/journal.pone.0225391 It lived around 35 million years ago (during the

Late Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "daw ...

), making it the youngest known protocetid to date. ''Aegicetus'' was discovered in 2007 at

Wadi El Hitan ( ar, وادي الحيتان, lit=Valley of the Whales ) is a paleontological site in the Faiyum Governorate of Egypt, some south-west of Cairo. It was designated a UNESCO World Heritage Site in July 2005 for its hundreds of fossils of some ...

( Gehannam Formation) as a relatively complete skeleton and a partial second specimen. They were assigned to a new

and species in 2019 by Philip D. Gingerich ''et al.'' Aegicetus size

''Aegicetus'' is reported to have been intermediate in form and functionally transitional in having a larger and more powerful vertebral column of a tail-powered swimmer. It differs from ''

Peregocetus ''Peregocetus'' is a genus of early whale that lived in what is now Peru during the Middle Eocene epoch. Its fossil was uncovered in 2011 in the Yumaque Formation of the Pisco Basin at Playa Media Luna by a team consisting of members from Bel ...

'' by lacking a firm

sacroiliac joint The sacroiliac joint or SI joint (SIJ) is the joint between the sacrum and the ilium bones of the pelvis, which are connected by strong ligaments. In humans, the sacrum supports the spine and is supported in turn by an ilium on each side. The ...

and from '' Rodhocetus'' by having smaller hind feet, indicating it were less capable of moving on land and relied less on its hind limbs to propel through the water.

References

{{Taxonbar, from=Q91878655 Protocetidae Fossils_of_Egypt Taxa named by Philip D. Gingerich Fossil taxa described in 2019 Prehistoric cetacean genera