Basilosaurus is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). First described in 1834, it was the first archaeocete and prehistoric whale known to science. Fossils attributed to the type species B. cetoides were discovered in the United States. They were originally thought to be of a giant reptile, hence the suffix "-saurus", Ancient Greek for "lizard". The animal was later found to be an early marine mammal, prompting attempts at renaming the creature, which failed as the rules of zoological nomenclature dictate using the original name given. Fossils were later found of the second species, B. isis, in 1904 in Egypt, Western Sahara, Morocco, Jordan, Tunisia, and Pakistan. Fossils have also been unearthed in the southeastern United States and Peru.
Basilosauridae is a family of extinct cetaceans. They lived during the middle to the early late Eocene and are known from all continents, including Antarctica. They were probably the first fully aquatic cetaceans. The group is noted to be a paraphyletic assemblage of stem group whales from which the monophyletic Neoceti are derived.
Dorudon ("spear-tooth") is a genus of extinct basilosaurid ancient whales that lived alongside Basilosaurus 40.4 to 33.9 million years ago in the Eocene. It was a small whale, with D. atrox measuring 5 metres (16 ft) long and weighing 1–2.2 metric tons. Dorudon lived in warm seas around the world and fed on small fish and mollusks. Fossils have been found along the former shorelines of the Tethys Sea in present-day Egypt and Pakistan, as well as in the United States, New Zealand and Western Sahara.
Wādī al-Ḥītān is a paleontological site in the Faiyum Governorate of Egypt, some 150 kilometres (93 mi) south-west of Cairo. It was designated a UNESCO World Heritage Site in July 2005 for its hundreds of fossils of some of the earliest forms of whale, the archaeoceti. The site reveals evidence for the explanation of one of the greatest mysteries of the evolution of whales: the emergence of the whale as an ocean-going mammal from a previous life as a land-based animal.
Archaeoceti, or Zeuglodontes in older literature, is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene. Representing the earliest cetacean radiation, they include the initial amphibious stages in cetacean evolution, thus are the ancestors of both modern cetacean suborders, Mysticeti and Odontoceti. This initial diversification occurred in the shallow waters that separated India and Asia 53 to 45 mya, resulting in some 30 species adapted to a fully oceanic life. Echolocation and filter-feeding evolved during a second radiation 36 to 35 mya.
Protocetus atavus is an extinct species of primitive cetacean from Egypt. It lived during the middle Eocene period 45 million years ago. The first discovered protocetid, Protocetus atavus was described by Fraas 1904 based on a cranium and a number of associated vertebrae and ribs found in middle Lutetian Tethyan marine limestone from Gebel Mokattam near Cairo, Egypt.
Protosiren is an extinct early genus of the order Sirenia. Protosiren existed throughout the Lutetian to Priabonian stages of the Middle Eocene. Fossils have been found in the far-flung locations like the United States, Africa (Egypt), Europe and Asia.
Cynthiacetus is an extinct genus of basilosaurid early whale that lived during the Late Eocene Specimens have been found in the southeastern United States and Peru.
Ancalecetus is an extinct genus of early whale known from the Late Eocene Birket Qarun Formation in Wadi Al-Hitan, Egypt. The species is named after anthropologist and primate researcher Elwyn L. Simons who discovered the type specimen in 1985.
The Jebel Qatrani Formation is a geologic formation located in the Faiyum Governorate of central Egypt. It is exposed between the Jebel Qatrani escarpment and the Qasr el Sagha escarpment, north of Birket Qarun lake near Faiyum. The formation conformably overlies the Qasr el Sagha Formation and is topped by the Widan el Faras Basalt. The age of the formation has been subject to debate, but the most recent research indicates that it covers both the latest parts of the Eocene and the Early Oligocene, spanning over the boundary between these two time periods.
Protocetidae, the protocetids, form a diverse and heterogeneous group of extinct cetaceans known from Asia, Europe, Africa, South America, and North America.
Pontogeneus is a genus of extinct cetacean known from fossils recovered from the Late Eocene sediments of the southeastern United States.
Saghacetus is an extinct genus of basilosaurid early whale, fossils of which have been found in the Upper Eocene Qasr el Sagha Formation, Egypt.
Aegyptocetus is an extinct genus of protocetid archaeocete whale known from Egypt.
Cordichelys is an extinct genus of podocnemidid turtle. It was around during the Eocene. Fossils of this turtle have been discovered at Wadi El Hitan as of November 2020.
Masracetus is an extinct genus of basilosaurid ancient whale known from the Late Eocene of Egypt.
Stromerius is an extinct genus of basilosaurid early whale known from the Late Eocene of Fayum, Egypt.
Eocetus is an extinct protocetid early whale known from the early-late Eocene Giushi Formation in Gebel Mokattam, outside Cairo, Egypt. The specimen was first named by Fraas as Mesocetus schweinfurthi. However, the name Mesocetus was previously used causing a change to the species name to Eocetus schweinfurthi. Since the genus was first described in the early 20th century, several other specimens, mostly isolated vertebrae, have been attributed to Eocetus, but the taxonomic status of these widely distributed specimens remain disputed.
Rayanistes is a genus of remingtonocetid whale from the Middle Eocene deposits in Egypt.
Aegicetus is an extinct genus of protocetid whale based on a partial skull with much of an associated postcranial skeleton discovered in Egypt. It lived around 35 million years ago, making it the youngest known protocetid to date. Aegicetus was discovered in 2007 at Wadi El Hitan as a relatively complete skeleton and a partial second specimen. They were assigned to a new genus and species in 2019 by Philip D. Gingerich et al.
Egypt 
