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''Basilosaurus'' (meaning "king lizard") 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, which prompted 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. ''Basilosaurus'' is considered to have been common in the Tethys Ocean. It was one of the largest, if not the largest, animals of the
Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
. It was the top predator of its environment, preying on sharks, large fish and other marine mammals, namely the dolphin-like '' Dorudon'', which seems to have been their predominant food source. ''Basilosaurus'' was at one point a wastebasket taxon, before the genus slowly started getting reevaluated, with many species of different Eocene cetacean being assigned to the genus in the past, however they are invalid or have been reclassified under a new or different genus, leaving only 2 confirmed species. ''Basilosaurus'' may have been one of the first fully aquatic cetaceans (sometimes referred to as the pelagiceti). ''Basilosaurus'', unlike modern cetaceans, had various types of teeth–such as canines and molars–in its mouth ( heterodonty), and it probably was able to chew its food in contrast to modern cetaceans which swallow their food whole.


Taxonomic history


Etymology

The two species of ''Basilosaurus'' are ''B. cetoides'', whose remains were discovered in the United States, and ''B. isis'', which was discovered in Egypt. ''B. cetoides'' is the type species for the genus. The Holotype Harlan found, was found in Ouachita Parish, Louisiana. Vertebrae were sent to the American Philosophical Society by a Judge Henry Bry of Ouachita Parish, Louisiana and Judge John Creagh of
Clarke County Clarke County may refer to: ;Places *One of five counties in the United States: **Clarke County, Alabama **Clarke County, Georgia **Clarke County, Iowa **Clarke County, Mississippi **Clarke County, Virginia * Clarke County, New South Wales, in Aust ...
, Alabama. Both fossils ended up in the hands of the anatomist Richard Harlan, who requested more examples from Creagh. The first bones were unearthed when rain caused a hillside full of sea shells to slide. The bones were lying in a curved line "measuring upwards of four hundred feet in length, with intervals which were vacant." Many of these bones were used as
andiron An andiron or firedog, fire-dog or fire dog is a bracket support, normally found in pairs, on which logs are laid for burning in an open fireplace, so that air may circulate under the firewood, allowing better burning and less smoke. They gene ...
s and destroyed; Bry saved the bones he could find, but was convinced more bones were still to be found on the location. Bry speculated that the bones must have belonged to a "sea monster" and supplied "a piece having the appearance of a tooth" to help determine which kind. Harlan identified the tooth as a wedge-shaped shell and instead focused on "a vertebra of enormous dimensions" which he assumed belonged to the order " Enalio-Sauri of Conybeare", "found only in the sub-cretaceous series." He noted that some parts of the vertebra were similar to those of '' Plesiosaurus'' and skull was similar to
Mosasaurus ''Mosasaurus'' (; "lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages o ...
, but that they were completely different in proportions. Comparing his vertebra to those of large dinosaurs such as '' Megalosaurus'' and '' Iguanodon'', Harlan concluded that his specimen was considerably larger—he estimated the animal to have been no less than long—and therefore suggested the name ''Basilosaurus'', meaning "king lizard". Harlan brought his assembled specimens (including fragments of jaw and teeth, humerus, and rib fragments) to the UK where he presented them to anatomist
Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Owe ...
. Owen concluded that the molar teeth were two-rooted, a dental morphology unknown in fishes and reptiles, and more complex and varied than in any known reptile, and therefore that the specimen must be a mammal. Owen correctly associated the teeth with cetaceans, but he thought it was an herbivorous animal, similar to sirenians. Consequently, Owen proposed renaming the find ''Zeuglodon cetoides'' ("whale-like yoke teeth" in reference to the double-rooted teeth) and Harlan agreed.


Wadi El Hitan

Wādī al-Ḥītān () is an Egyptian sandstone formation where many early-whale skeletons were discovered. German botanist Georg August Schweinfurth discovered the first archaeocete whale in Egypt (''Zeuglodon osiris'', now ''
Saghacetus ''Saghacetus'' is an extinct genus of basilosaurid early whale, fossils of which have been found in the Upper Eocene (middle Priabonian, ) Qasr el Sagha Formation, Egypt (, paleocoordinates ). In 1879, German botanist Georg August Schweinfurt ...
osiris'') in 1879. He visited the Qasr el Sagha Formation in 1884 and 1886 and missed the now famous Wadi El Hitan by a few kilometers. German paleontologist Wilhelm Barnim Dames described the material, including the type specimen of ''Z. osiris'', a well-preserved dentary. Hugh Beadnell, head of the Geological Survey of Egypt 1896–1906, named and described ''Zeuglodon isis'' in based on a partial mandible and several vertebrae from Wadi El Hitan in Egypt. described a skull and some vertebrae of a smaller archaeocete and named it ''Prozeuglodon atrox'', now known today as '' Dorudon atrox''. discovered deciduous teeth in this skull and it was then believed to be a juvenile 'Pro'''zeuglodon isis'' for decades before more complete fossils of mature ''Dorudon'' were discovered. In the 1980s,
Elwyn L. Simons Elwyn LaVerne Simons (July 14, 1930 – March 6, 2016) was an American paleontologist, paleozoologist, and a wildlife conservationist for primates. He was known as the father of modern primate paleontology for his discovery of some of humankind ...
and Philip D. Gingerich started to excavate at Qasr el-Sagha and Wadi El Hitan with the hope of finding material that could match archaeocete fossils from Pakistan. Since then, over 500 archaeocete skeletons have been found at these two locations, of which most are ''B. isis'' or ''D. atrox'', several of the latter carrying bite marks assumed to be from the former. A 1990 paper described additional fossils including foot bones and speculated that the reduced hind limbs were used as copulatory guides. One thing that was noted, was that whale fossils were so common, that when a mason company looked at their newest table counter, they realized that they had created a cross section of a 40 million year old Basilosaurid fossil. This find was another thing that caught the eye of Gingerich. In 2016, a complete skeleton, the first-ever find for ''Basilosaurus'', was uncovered in Wadi El Hitan, preserved with the remains of its prey, including a ''Dorudon'' and several species of fish. The whale's skeleton also shows signs of scavenging or predation by large sharks such as the otodontid ''Carcharocles sokolovi''.


Wastebasket taxa

Many dubious species have been assigned to ''Basilosaurus'' in the past which have since been invalidated or were too incomplete to determine anything.


''Nomina dubia''

A ''
nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...
'' is a scientific name that is of unknown or doubtful application. There are a few documented cases of this being applied to Basilosaurus in the past. * ''Zeuglodon wanklyni'', was a supposed species of Basilosaurus, that described in 1876 based on a skull found in the Wanklyn's Barton Cliff in the United Kingdom. This single specimen, however, quickly disappeared and has since been declared a ''
nomen nudum In taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published with an adequate descr ...
'' or referred to as ''
Zygorhiza ''Zygorhiza'' ("Yoke-Root") is an extinct genus of basilosaurid early whale known from the Late Eocene (Priabonian, 38–34 Ma) of Louisiana, Alabama, and Mississippi, United States, and the Bartonian (43–37 Ma on the New Zealand geologic time ...
wanklyni''. * ''Zeuglodon vredense'' or ''vredensis'' was named in the 19th century based on a single, isolated tooth without any kind of accompanying description, and therefore declared it a ''nomen nudum''. * ''Zeuglodon puschi ' was a species that was said to come from Poland, it was named by . noted that the species is based on an incomplete vertebra of indeterminable position and, therefore, that the species is invalid. * ''Zeuglodon brachyspondylus'' was described by
Johannes Peter Müller Johannes Peter Müller (14 July 1801 – 28 April 1858) was a German physiologist, comparative anatomy, comparative anatomist, ichthyology, ichthyologist, and herpetology, herpetologist, known not only for his discoveries but also for his ability ...
based on some vertebrae from "''Zeuglodon hydrarchus''", better known as Dr. Albert Koch's "Hydrarchos". , synonymized it with ''
Pontogeneus ''Pontogeneus'' ('' nomen dubium'') is a genus of extinct cetacean known from fossils recovered from Late Eocene sediments (Bartonian-Priabonian stages) of the southeastern United States (most notably Alabama and Florida). Classification When ...
priscus'', which a 2005 study declared a ''
nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...
''.


Reassigned species

* ''Basilosaurus drazindai'' was named by a 1997 study based on a single lumbar vertebra. Originally, the species was thought to have lived in Pakistan and the UK. It was later declared a ''nomen dubium'' by Uhen (2013), but Gingerich and Zouhri (in press) reassigned it to the genus '' Eocetus''. This species was at one point in time concluded to be the earliest record of the genus Basilosaurus, before its reclassification. * ''Zeuglodon elliotsmithii'', ''Z. sensitivius'', ''Z. sensitivus'', and ''Z. zitteli'' were synonymized and grouped under the genus ''
Saghacetus ''Saghacetus'' is an extinct genus of basilosaurid early whale, fossils of which have been found in the Upper Eocene (middle Priabonian, ) Qasr el Sagha Formation, Egypt (, paleocoordinates ). In 1879, German botanist Georg August Schweinfurt ...
'' by a 1992 study. * ''Zeuglodon paulsoni'' from Ukraine (then the Russian Empire) was named by . It was synonymized with '' Platyosphys'' but is now considered ''nomen dubium''. Gingerich and Zouhri (in press), however, maintain ''Platyosphys'' as valid. * ''Basilosaurus caucasicus'' also known as Basilosaurus caucasicum or Zeuglodon caucasicum was species described in the Russian Empire, it gets its name from the Caucasus of where it was found in the 1890s. The specimen was found. The fossil was reassigned to the toothed whale Microzeuglodon caucasicum. * ''Basilosaurus harwoodi ''was discovered in Murray River near Wellington in South Australia, this species classification is quite controversial, yet today it is agreed that the Australian, Basilosaurus harwoodi (or Zeuglodon harwoodi) is most likely a member of the genus Metasqualodon as noted by T. S. Hall 1911. *In 1906, German naturalist
Othenio Abel Othenio Lothar Franz Anton Louis Abel (June 20, 1875 – July 4, 1946) was an Austrian paleontologist and evolutionary biologist. Together with Louis Dollo, he was the founder of "paleobiology" and studied the life and environment of fossilized or ...
thought fossils from the Eocene of Alabama, previously described in 1900 as being a ''Basilosaurus'' hip bone by American zoologist
Frederic Augustus Lucas Frederic Augustus Lucas, Sc.D. (March 25, 1852 – February 9, 1929) was a zoologist who served as a curator of the Brooklyn Museum and director of the American Museum of Natural History. He was an expert on the osteology and anatomy of birds. Bio ...
, represented the shoulder of a large bird similar to '' Gastornis'', and named it ''Alabamornis gigantea''. Lucas later countered his conclusion in 1908 as he reassigned the fossil specimens to the original conclusion of a Basilosaurus hip bone.


Description

With ''B. cetoides'' measuring long and ''B. isis'' measuring long, ''Basilosaurus'' is one of the largest animals known to exist between the K–Pg extinction event 66 million years ago (mya) and around 15 million years ago when modern
cetacea 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 ...
ns began to reach enormous sizes. Body mass estimates for both species have been varied throughout numerous literature. Gingerich initially estimated the body mass of ''B. cetoides'' at and ''B. isis'' at , but later considered his estimates to be questionable due to the unique morphology of this genus. Waugh and Thewissen later proposed lower body mass estimates of for ''B. cetoides'' and for ''B. isis'' based on the same specimens used for Gingerich's original estimates. ''Basilosaurus'' is distinguished from other genera of basilosaurids by its larger body size and its more elongated posterior thoracic, lumbar, and anterior caudal vertebrae. ''Basilosaurus'' does not have the vertically oriented metapophyses seen in its closest relative the basilosaurid known as '' Basiloterus''. ''Basilosaurus'' is considered to be the largest of archeocete whales.


Cranium

The dental formula for ''B. isis'' is . The upper and lower molars and second to fourth premolars are double-rooted and high-crowned. The head of ''Basilosaurus'' did not have room for a melon like modern toothed whales, and the brain was smaller in comparison, as well. They are not believed to have had the social capabilities of modern whales. A 2011 study concluded that the skull of ''Basilosaurus'' is asymmetrical like in modern toothed whales, and not, as previously assumed, symmetrical like in baleen whales and artiodactyls (which are closely related to cetaceans). In modern toothed whales, this asymmetry is associated with high-frequency sound production and echolocation, neither of which is thought to have been present in ''Basilosaurus''. This probably evolved to detect sound underwater, with a fatty sound-receiving pad in the mandible. In the skull, the inner and middle ear are enclosed by a dense
tympanic bulla The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal. It originates as a separate bone (tympanic ...
. The
synapomorphic In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...
cetacean air sinus system is partially present in basilosaurids, including the pterygoid, peribullary, maxillary, and frontal sinuses. The
periotic bone The periotic bone is the single bone that surrounds the inner ear of mammals. It is formed from the fusion of the prootic, epiotic, and opisthotic bones. References External links * http://www.encyclopedia.com/doc/1O8-perioticbone.html ...
, which surrounds the inner ear, is partially isolated. The
mandibular canal In human anatomy, the mandibular canal is a canal within the mandible that contains the inferior alveolar nerve, inferior alveolar artery, and inferior alveolar vein. It runs obliquely downward and forward in the ramus, and then horizontally f ...
is large and laterally flanked by a thin bony wall, the pan bone or acoustic fenestra. These features enabled basilosaurs to hear directionally in water. The ear of basilosaurids is more derived than those in earlier archaeocetes, such as remingtonocetids and protocetids, in the acoustic isolation provided by the air-filled sinuses inserted between the ear and the skull. The basilosaurid ear did, however, have a large external auditory meatus, strongly reduced in modern cetaceans, but, though this was probably functional, it can have been of little use under water.


Hind limbs

A individual of ''B. isis'' had hind limbs with fused tarsals and only three digits. The limited size of the limb and the absence of an articulation with the sacral vertebrae make a locomotory function unlikely. Analysis has shown that the reduced limbs could rapidly adduct between only two positions. Possible uses for the structure have been given, such as clasper-like body functions (compare to the function of pelvic spurs, the last vestiges of limbs in certain modern snakes). These limbs would have been used to guide the animals' long bodies during mating.


Spine and movement

A complete ''Basilosaurus'' skeleton was found in 2015, and several attempts have been made to reconstruct the vertebral column from partial skeletons. estimated a total of 58 vertebrae, based on two partial and nonoverlapping skeletons of ''B. cetoides'' from Alabama. More complete fossils uncovered in Egypt in the 1990s allowed a more accurate estimation: the vertebral column of ''B. isis'' has been reconstructed from three overlapping skeletons to a total of 70 vertebrae with a vertebral formula interpreted as seven cervical, 18 thoracic, 20 lumbar and sacral, and 25 caudal vertebrae. The vertebral formula of ''B. cetoides'' can be assumed to be the same. ''Basilosaurus'' has an anguilliform ( eel-like) body shape because of the elongation of the centra of the thoracic through anterior caudal vertebrae. In life, these vertebrae were filled with marrow, and because of the enlarged size, this made them buoyant. ''Basilosaurus'' probably swam predominantly in two dimensions at the sea surface, in contrast to the smaller '' Dorudon'', which was likely a diving, three-dimensional swimmer. The skeletal anatomy of the tail suggests that a small fluke was probably present, which would have aided only vertical motion. Similarly sized thoracic, lumbar, sacral, and caudal vertebrae imply that it moved in an anguilliform fashion, but predominantly in the vertical plane. Paleontologist Philip D. Gingerich theorized that ''Basilosaurus'' may also have moved in a very odd, horizontal anguilliform fashion to some degree, something completely unknown in modern cetaceans. The vertebrae appear to have been hollow, and likely also fluid-filled. This would imply that ''Basilosaurus'' typically functioned in only two dimensions at the ocean surface, compared with the three-dimensional habits of most other cetaceans. Judging from the relatively weak axial musculature and the thick bones in the limbs, ''Basilosaurus'' is not believed to have been capable of sustained swimming or deep diving, or terrestrial locomotion. Basilosaurus did still have an elbow joint in its flipper like a seal.


Paleobiology


Feeding

The cheek teeth of ''Basilosaurus'' retain a complex morphology and functional occlusion. Heavy wear on the teeth reveals that food was first chewed then swallowed. Scientists were able to estimate the bite force of ''Basilosaurus'' by analyzing the scarred skull bones of another species of prehistoric whale, ''Dorudon'', and concluded they could bite with a force of . Analyses of the stomach contents of ''B. cetoides'' has shown that this species fed exclusively on fish and large sharks, while bite marks on the skulls of juvenile ''Dorudon'' have been matched with the dentition of ''B. isis'', suggesting a dietary difference between the two species, similar to that found in different populations of modern killer whales. It was probably an active predator rather than a scavenger. The discovery of juvenile ''Dorudon'' at Wadi Al Hitan bearing distinctive bite marks on their skulls indicates that ''B. isis'' would have aimed for the skulls of its victims to kill its prey, and then subsequently torn its meals apart, based on the disarticulated remains of the ''Dorudon'' skeletons. The finding further cements theories that ''B. isis'' was an apex predator that may have hunted newborn and juvenile ''Dorudon'' at Wadi Al Hitan when mothers of the latter came to give birth. The stomach contents of an elderly male '' B. isis'' not only includes ''Dorudon'' but the fish ''
Pycnodus ''Pycnodus'' (from el, πυκνός , 'dense' and el, ὀδούς 'tooth') is an extinct genus of ray-finned fish ranging from the Jurassic to Eocene periods. As its name suggests, it is the type genus of Pycnodontiformes. The known whole ...
mokattamensis''.


Paleoecology

''Basilosaurus'' would have been the top predator of its environment. It lived in the warm tropical environment of the Eocene in areas abundant with sea grasses, such as ''
Thalassodendron ''Thalassodendron'' is a genus of seagrass in the family Cymodoceaceae, described as a genus in 1970. It grows along the shores of the Indian Ocean, the western Pacific Ocean and around Australasia. The genus was circumscribed by Cornelis den Ha ...
'', '' Thalassia'' (also known as turtle grass) and ''
Halodule ''Halodule'' is a genus of plants in the family Cymodoceaceae described as a genus in 1841. It is widespread on tropical and semi-tropical ocean shores of all continents except Europe and Antarctica. Species Hybridization has been reported in ...
''. It would have coexisted with the dolphin-like ''Dorudon'', the whales '' Cynthiacetus'' and '' Basiloterus'', the primitive sirenian '' Protosiren'', the early elephant '' Moeritherium'', the sea turtle ''
Puppigerus ''Puppigerus'' is an extinct genus of sea turtle from the Eocene. It is known from finds in the United States, the United Kingdom, Belgium, Denmark, and Uzbekistan. Taxonomy ''Puppigerus'' was described by Edward Drinker Cope in 1870. As of 1997 ...
'' and many sharks, such as ''
Galeocerdo alabamensis ''Galeocerdo alabamensis'' is an extinct relative of the modern tiger shark. Nomenclature of this shark has been debated, and recent literature identified it more closely with the ''Physogaleus'' genus of prehistoric shark, rather than ''Galeocer ...
'', '' Physogaleus'', '' Otodus'', '' Squatina prima'', ''
Striatolamia ''Striatolamia'' is an extinct genus of sharks belonging to the family Odontaspididae. These extinct sharks lived from the Early Paleocene to Late Miocene (61.7 to 10.3 Ma). Etymology The Latin genus name ''Striatolamia'' refers to the striati ...
'', ''
Carcharocles sokolovi ''Otodus sokolovi'' is an extinct species or chronospecies of large shark in the family Otodontidae which may represent a transitional chronospecies between '' Otodus auriculatus'' and '' Otodus angustidens''. They differ from the former with a ...
'' and '' Isurus praecursor''.


Extinction

Basilosaurus fossil record seems to end at about 35–33.9 mya. Basilosaurus extinction coincides with the Eocene–Oligocene extinction event which happened 33.9 mya, which also resulted in the extinction of almost all other archaeocetes. The event has been attributed to volcanic activity, meteor impacts or a sudden change in climate (such as the environment getting cooler), the latter of which might have caused changes in the ocean by disrupting oceanic circulation. ''Basilosaurus'' went extinct leaving no descendants. Despite this new currents and deep ocean upwelling favored the diversification of modern cetaceans such as early toothed and baleen whales.


Classification

Below is the phylogenetic analysis on the placement of ''Basilosaurus''. Two subfamilies exist in Basilosauridae: Basilosaurinae which includes ''Basilosaurus'', and Dorudontinae. These groups have been declared invalid in the past. ''Dorudon'' remains were once thought to represent juvenile ''Basilosaurus''.


In popular culture

The species ''B. cetoides'' is the
state fossil Most American states have made a state fossil designation, in many cases during the 1980s. It is common to designate one species in which fossilization has occurred, rather than a single specimen, or a category of fossils not limited to a single ...
of Alabama and Mississippi. During the early 19th century, ''B. cetoides'' fossils were so common (and sufficiently large) that they were regularly used as furniture in the American South. ''Basilosaurus'' is featured in the BBC's
Walking with series ''Walking with...'' is a palaeontology media franchise produced and broadcast by the BBC Natural History Unit. The franchise began with the critically acclaimed series ''Walking with Dinosaurs'' (1999), created by Tim Haines. By far the most wa ...
in ''
Walking with Beasts ''Walking with Beasts'', marketed as ''Walking with Prehistoric Beasts'' in North America, is a 2001 six-part nature documentary television miniseries created by Impossible Pictures and produced by the BBC Natural History Unit, the Discovery C ...
'' and ''
Sea Monsters Sea monsters are beings from folklore believed to dwell in the sea and often imagined to be of immense size. Marine monsters can take many forms, including sea dragons, sea serpents, or tentacled beasts. They can be slimy and scaly and are ofte ...
''. In the novel Moby Dick, by Herman Melville,
Ishmael Ishmael ''Ismaḗl''; Classical/Qur'anic Arabic: إِسْمَٰعِيْل; Modern Standard Arabic: إِسْمَاعِيْل ''ʾIsmāʿīl''; la, Ismael was the first son of Abraham, the common patriarch of the Abrahamic religions; and is cons ...
cites the ''Basilosaurus'' during his studies as a possible whale fossil.


See also

* Evolution of cetaceans


References


Cited literature

* ** * * * ** * * * * ** *


Further reading

* * * * ** * **


External links

{{Taxonbar, from=Q134884 Eocene mammals of North America Eocene mammals of Africa Basilosauridae Transitional fossils Prehistoric cetacean genera Fossil taxa described in 1834 Taxa named by Richard Harlan Taxa named by Charles William Andrews Symbols of Alabama Symbols of Mississippi Fossil cetaceans misidentified as reptiles Eocene mammals of Asia