Kentisuchus
Encyclopedia
Kentisuchus is an extinct genus
of tomistomine
. It is considered one of the most basal
members of the subfamily. Fossil
s have been found from England
that date back to the early Eocene
. There is also evidence that suggests that the genus was also present in Ukraine
at the time, although material found from the Ukrainian locality cannot be referred to any particular species.
in 1836. Buckland named "Crocodylus" spenceri on the basis of a partial skull found from the Isle of Sheppey
in Kent
, England. Another tomistomine known as "Crocodylus" toliapicus was later described by Richard Owen
, who considered it synonymous with “Crocodylus” spenceri yet kept the new name. In 1888 Richard Lydekker
considered "C." toliapicus synonymous with two other known crocodilians, "C." champsoides, named by Owen, and "C." arduini, named by De Zigno, and reapplied the name "C." spenceri to all of these species.
The genus name Kentisuchus was constructed only after it was realized that these tomistomine specimens were clearly distinct from the genus Crocodylus
and that some specimens originally assigned to "C." spenceri belonged to entirely different genera and species. "C." arduini was reassigned to the new genus Megadontosuchus
in the same paper that Kentisuchus was first described in. "C." toliapicus and "C." champsoides were both found to be species of Kentisuchus, the former being considered the type species
. "C." spenceri has provisionally been referred to Kentisuchus as well.
suggest that K. spenceri is closely related to Dollosuchus. An apparent close relationship between K. spenceri and Eosuchus lerichei
has been used to imply that the latter species was a tomistomine, while it is now thought that Eosuchus is a basal gavialoid that is crownward
to most other members of the superfamily
.
localities that were once part of a Tethysian
archipelago
, suggests that it came to these islands after a tomistomine dispersal event south from mainland Europe
rather than north from Africa
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of tomistomine
Tomistominae
Tomistominae is a subfamily of crocodylians that includes one living species, the False gharial. Many more extinct species are known, extending the range of the subfamily back to the Eocene epoch...
. It is considered one of the most basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
members of the subfamily. Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s have been found from England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
that date back to the early Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
. There is also evidence that suggests that the genus was also present in Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
at the time, although material found from the Ukrainian locality cannot be referred to any particular species.
Species
The genus Kentisuchus was constructed by Charles Mook in 1955 as a replacement name for the basal tomistomine "Crocodylus" spenceri, named by William BucklandWilliam Buckland
The Very Rev. Dr William Buckland DD FRS was an English geologist, palaeontologist and Dean of Westminster, who wrote the first full account of a fossil dinosaur, which he named Megalosaurus...
in 1836. Buckland named "Crocodylus" spenceri on the basis of a partial skull found from the Isle of Sheppey
Isle of Sheppey
The Isle of Sheppey is an island off the northern coast of Kent, England in the Thames Estuary, some to the east of London. It has an area of . The island forms part of the local government district of Swale...
in Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...
, England. Another tomistomine known as "Crocodylus" toliapicus was later described by Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
, who considered it synonymous with “Crocodylus” spenceri yet kept the new name. In 1888 Richard Lydekker
Richard Lydekker
Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...
considered "C." toliapicus synonymous with two other known crocodilians, "C." champsoides, named by Owen, and "C." arduini, named by De Zigno, and reapplied the name "C." spenceri to all of these species.
The genus name Kentisuchus was constructed only after it was realized that these tomistomine specimens were clearly distinct from the genus Crocodylus
Crocodylus
Crocodylus is one of three genera from the Crocodylinae subfamily extending from the Crocodylidae family.Established species include three extinct species:* † Crocodylus acer - probably represents a distinct genus....
and that some specimens originally assigned to "C." spenceri belonged to entirely different genera and species. "C." arduini was reassigned to the new genus Megadontosuchus
Megadontosuchus
Megadontosuchus is a genus of tomistomine from the middle Eocene of Italy. Fossils have been found from Monte Duello in the province of Verona. The genus is currently monotypic, with the type and only species being M. arduini. The species was originally named in 1880, although it was assigned to...
in the same paper that Kentisuchus was first described in. "C." toliapicus and "C." champsoides were both found to be species of Kentisuchus, the former being considered the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
. "C." spenceri has provisionally been referred to Kentisuchus as well.
Phylogenetics
K. spenceri may be congeneric with M. arduini and Dollosuchus dixoni, according to several more recent studies. If this is the case then the name Dollosuchus has seniority over the other two, although it is likely the three taxon will remain their own distinct species. Other recently conducted phylogenetic analysesPhylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
suggest that K. spenceri is closely related to Dollosuchus. An apparent close relationship between K. spenceri and Eosuchus lerichei
Eosuchus
Eosuchus is an extinct genus of gavialoid crocodilian. It is among the most basal of all gavialoids, lying crownward of all other known members of the superfamily, including earlier members such as Thoracosaurus and Eothoracosaurus. Fossils have been found from France as well as eastern North...
has been used to imply that the latter species was a tomistomine, while it is now thought that Eosuchus is a basal gavialoid that is crownward
Crown group
A crown group is a group consisting of living representatives, their ancestors back to the most recent common ancestor of that group, and all of that ancestor's descendants. The name was given by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms...
to most other members of the superfamily
Taxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
.
Paleobiology
The close relation of Kentisuchus and Dollosuchus, which are known from European localities that were on the mainland during the early Eocene, to Megadontosuchus, which is known from ItalianItaly
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
localities that were once part of a Tethysian
Tethys Ocean
The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...
archipelago
Archipelago
An archipelago , sometimes called an island group, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- and πέλαγος – pélagos through the Italian arcipelago...
, suggests that it came to these islands after a tomistomine dispersal event south from mainland Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
rather than north from Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
.
External links
- Kentisuchus in the Paleobiology DatabasePaleobiology Database' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...