''Aegyptocetus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 ...

archaeocete

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 ...

known from

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 ...

Taxonomy

''Aegyptocetus'' is known from the articulated

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

MSNTUP I-15459, an almost complete

cranium The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

, lower jaws (with teeth) and a partial

postcrania Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

(cervical and thoracic

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

e and

rib In vertebrate anatomy, ribs ( la, costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the ches ...

s). The specimen was recovered when

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or Dolomite (mineral), dolomite. Marble is typically not Foliation (geology), foliated (layered), although there are exceptions. In geology, the ...

ized limestone was imported commercially to Italy. It was collected in the Khashm el-Raqaba limestone quarry (, paleocoordinates ) from the Gebel Hof Formation on the northern flank of Wadi Tarfa in the Eastern Desert of

, dating to the late

Mokattam The Mokattam ( arz, المقطم , also spelled Muqattam), also known as the Mukattam Mountain or Hills, is the name of a range of hills and a suburb in them, located in southeastern Cairo, Egypt. Etymology The Arabic name ''Mokattam'' ...

ian age of the middle

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

, about . Its cause of death may have been an attack by a large

shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...

as pattern of shark tooth marks preserved on the ribs. ''Aegyptocetus'' was first named by Giovanni Bianucci and Philip D. Gingerich in

2011 File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrate ...

and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''Aegyptocetus tarfa''. The generic name is derived from ''Aegyptus'',

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for Egypt, and ''cetus'', Latin for whale. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

refers to Wadi Tarfa, the desert valley where the holotype was found.

Description

''Aegyptocetus'' had features in its cranium and dentaries adapted for hearing in water. Its thoracic vertebrae (T1–T8), however, had long neural spines which is a characteristic of the weight-bearing system of land-living mammals retained in protocetids, such as '' Rodhocetus'' and '' Qaisracetus'', but absent in the more derived

basilosaurids 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.Buono M, Fordyce R.E., Marx F. ...

, such as '' Dorudon''. This suggests that ''Aegyptocetus'', like other protocetids, was able to support its body on land and probably was semi-aquatic.

References

Notes

Sources

* {{Taxonbar, from1=Q28605495, from2=Q3605934 Protocetidae Eocene mammals of Africa Fossil taxa described in 2011 Prehistoric cetacean genera