Dollosuchus

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Dollosuchus
Temporal range: Early Eocene–Middle Eocene
Dollosuchus dixoni.jpg
Fossils referred to Gavialis dixoni (now Dollosuchus dixoni) by Richard Owen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Family: Gavialidae
Subfamily: Tomistominae
Genus: Dollosuchus
Swinton, 1937 vide Owen, 1850
Type species
Dollosuchus dixoni
Owen, 1850
Synonyms

Dollosuchus (meaning "Louis Dollo's crocodile") is an extinct monospecific genus of tomistomine crocodilian originally named as a species of Gavialis . [1] It is a basal form possibly related to Kentisuchus , according to several phylogenetic analyses that have been conducted in recent years, [2] [3] [4] and is the oldest known tomistomine to date. Fossils have been found from Belgium and the United Kingdom. [5] It had large supratemporal fenestrae in relation to its orbits, similar to Kentisuchus and Thecachampsa . [6]

Contents

Dollosuchus was originally described on the basis of numerous mandibular fragments found from the Early to Middle Eocene Bracklesham Beds Formation in the United Kingdom. The material cannot be distinguished from other related longirostrine, or long-snouted, crocodilians. A nearly complete skeleton from Belgium (IRScNB 482) discovered in 1915 and described by Swinton in 1937, [5] and referred to Dollosuchus, formed the basis of the new taxon Dollosuchoides densmorei . [4] The holotype, BMNH 26125 and BMNH 26126, is now on display at the World of Kina museum in Ghent, Belgium.

Species

The type species of Dollosuchus is D. dixoni. Many other species that once belonged to other genera have been proposed as members of the genus, but little work has been published to support these claims. Charactosuchus kugleri , another Eocene crocodilian, has been suggested to be synonymous with Dollosuchus, [7] but this is no longer likely because C. kugleri is now thought to be a member of the family Crocodylidae, and thus closer related to modern crocodiles than to gharials. It has been suggested that Kentisuchus spenceri, Megadontosuchus arduini , and Dollosuchus dixoni are cogeneric. If this is the case, the genus name Dollosuchus would be adopted for all three species, as the name has seniority over the other two. [8] [9]

Related Research Articles

<i>Gavialis</i> Genus of reptiles

Gavialis is a genus of crocodylians that includes the living gharial Gavialis gangeticus and one known extinct species, Gavialis bengawanicus.G. gangeticus comes from the Indian Subcontinent, while G. bengawanicus is known from Java. Gavialis likely first appeared in the Indian Subcontinent in the Pliocene and dispersed into the Malay Archipelago through a path called the Siva–Malayan route in the Quaternary. Remains attributed to Gavialis have also been found on Sulawesi and Woodlark Island east of the Wallace Line, suggesting a prehistoric lineage of Gavialis was able to traverse marine environments and reach places possibly as far as western Oceania.

Atacisaurus is an extinct dubious genus of gavialoid crocodylian. Fossils have been found in the Grès de Carcassonne Member of the Sables du Castrais Formation in Laure-Minervois, France that date back to the Middle Eocene.

<i>Toyotamaphimeia</i> Extinct genus of reptiles

Toyotamaphimeia is a genus of extinct gavialid crocodylian which lived in Japan and Taiwan during the Pleistocene. A specimen recovered in 1964 at Osaka University during the construction of a new science building has been dated to around 430–380 thousand years old based on the stratum in which it was found. Toyotamaphimeia was a fairly large crocodylian measuring approximately 6.3–7.3 metres (21–24 ft) long. Two species are named, T. machikanensis from Japan and T. taiwanica from Taiwan, both originally described as members of the genus Tomistoma.

<i>Gavialosuchus</i> Extinct genus of reptiles

Gavialosuchus is an extinct genus of gavialoid crocodylian from the early Miocene of Europe. Currently only one species is recognized, as a few other species of Gavialosuchus have since been reclassified to other genera.

<i>Harpacochampsa</i> Extinct genus of crocodilian

Harpacochampsa is a poorly known Early Miocene crocodilian from the Bullock Creek lagerstätte of the Northern Territory, Australia. The current specimen consists of a partial skull and fragments of a long, slender snout reminiscent of that of a false gharial, demonstrating that it was a piscivore in life.

<i>Megadontosuchus</i> Extinct genus of reptiles

Megadontosuchus is an extinct monospecific genus of gavialoid crocodylian, traditionally regarded as a member of Tomistominae, 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 Megadontosuchus arduini. The species was originally named in 1880, although it was assigned to the genus Crocodilius. The genus was first erected by paleontologist Charles C. Mook in 1955 along with the genus Kentisuchus, which was also first classified as Crocodilius. No holotype for Megadontosuchus was designated in 1880, and a lectotype wasn't proposed until 2007.

<i>Asiatosuchus</i> Extinct genus of reptiles

Asiatosuchus is an extinct genus of crocodyloid crocodilians that lived in Eurasia during the Paleogene. Many Paleogene crocodilians from Europe and Asia have been attributed to Asiatosuchus since the genus was named in 1940. These species have a generalized crocodilian morphology typified by flat, triangular skulls. The feature that traditionally united these species under the genus Asiatosuchus is a broad connection or symphysis between the two halves of the lower jaw. Recent studies of the evolutionary relationships of early crocodilians along with closer examinations of the morphology of fossil specimens suggest that only the first named species of Asiatosuchus, A. grangeri from the Eocene of Mongolia, belongs in the genus. Most species are now regarded as nomina dubia or "dubious names", meaning that their type specimens lack the unique anatomical features necessary to justify their classification as distinct species. Other species such as "A." germanicus and "A." depressifrons are still considered valid species, but they do not form an evolutionary grouping with A. grangeri that would warrant them being placed together in the genus Asiatosuchus.

Dollosuchoides, colloquially known as the Crocodile of Maransart, is an extinct monospecific genus of gavialoid crocodilian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found in the Brussel Formation of Maransart, Belgium and date back to the middle Eocene.

Eogavialis is an extinct genus of eusuchian crocodylomorph, usually regarded as a gavialoid crocodylian. It superficially resembles Tomistoma schlegelii, the extant false gharial, and consequently material from the genus was originally referred to Tomistoma. Indeed, it was not until 1982 that the name Eogavialis was constructed after it was realised that the specimens were from a more basal form.

<i>Eosuchus</i> Extinct genus of reptiles

Eosuchus is an extinct genus of eusuchian crocodylomorph, traditionally regarded as a gavialoid crocodilian. It might have been among the most basal of all gavialoids, lying crownward of all other known members of the superfamily, including earlier putative members such as Thoracosaurus and Eothoracosaurus. Fossils have been found from France as well as eastern North America in Maryland, Virginia, and New Jersey. The strata from which specimens have been found date back to the late Paleocene and early Eocene epochs.

Ferganosuchus is an extinct monospecific genus of gavialid crocodilian. The genus is thought to be a tomistomine, although it has been suggested that Ferganosuchus may be a more basal gavialoid. Fossils have been found in the region of Kazakhstan and Kyrgyzstan that date back the middle Eocene. The genus is well known from fairly complete specimens, unlike most other Asian tomistomines, whose remains tend to be more fragmentary.

<i>Kentisuchus</i> Extinct genus of reptiles

Kentisuchus is an extinct genus of gavialoid crocodylian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found from England and France that date back to the early Eocene. The genus has also been recorded from Ukraine, but it unclear whether specimens from Ukraine are referable to Kentisuchus.

Maroccosuchus zennaroi is an extinct gavialoid crocodylian from the Early Eocene of Morocco, traditionally regarded as a member of the subfamily Tomistominae.

Paratomistoma is an extinct monospecific genus of gavialoid crocodylian. It is based on the holotype specimen CGM 42188, a partial posterior skull and lower jaw discovered at Wadi Hitan, Egypt, in Middle Eocene-age rocks of the Gehannam Formation. The skull is unfused but considered morphologically mature. Paratomistoma was named in 2000 by Christopher Brochu and Philip Gingerich; the type species is P. courti in honor of Nicholas Court, who found CGM 42188. They performed a phylogenetic analysis and found Paratomistoma to be a derived member of Tomistominae, related to the false gharial. It may have been a marine or coastal crocodilian.

Prodiplocynodon is an extinct genus of basal crocodyloid crocodylian. It is one of the only crocodyloids known from the Cretaceous and existed during the Maastrichtian stage. The only species of Prodiplocynodon is the type species P. langi from the Lance Formation of Wyoming, known only from a single holotype skull lacking the lower jaw.

<i>Thecachampsa</i> Extinct genus of reptiles

Thecachampsa is an extinct genus of gavialoid crocodylian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found from the eastern United States in deposits of Miocene age. Those named in the 19th century were distinguished primarily by the shape of their teeth, and have since been combined with T. antiquus. More recently erected species were reassigned from other genera, although their assignment to Thecachampsa has since been questioned.

<span class="mw-page-title-main">Tomistominae</span> Subfamily of reptiles

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. In contrast to the false gharial, which is a freshwater species that lives only in southeast Asia, extinct tomistomines had a global distribution and lived in estuaries and along coastlines.

<i>Gavialis browni</i> Extinct species of reptile

Gavialis browni is an extinct species of the crocodylian genus Gavialis and a close relative of the living gharial Gavialis gangeticus.

<i>Noteosuchus</i> Extinct genus of reptiles from the earliest Triassic deposits of South Africa

Noteosuchus is an extinct genus of basal rhynchosaur known from the earliest Triassic deposits of Eastern Cape Province, South Africa. It was first named by David Meredith Seares Watson in 1912 and the type species is Eosuchus colletti. The generic name Eosuchus is preoccupied by the generic name of Eosuchus lerichei Dollo, 1907, a gavialoid crocodilian known from northern France. Thus, an alternative generic name, Noteosuchus, was proposed by Robert Broom in 1925. The generic name erected by Broom (1925) is a compound, meaning "Not Eosuchus", while "Eosuchus" is derived from the name of Eos, the goddess of the dawn in Greek mythology, and suchus, Latinized from the Greek souchos, an Egyptian crocodile god, thus meaning "dawn crocodile". The specific name, colletti, honors Mr. Collett for the discovery of the holotype and only known specimen.

Tomistoma cairense is an extinct species of gavialoid crocodilian from the Lutetian stage of the Eocene era. It lived in North East Africa, especially Egypt. Remains of T. cairense have been found in the Mokattam Formation, in Mokattam, Egypt. Tomistoma cairense did not have a Maxilla process within their lacrimal gland, whereas all extant (living) crocodilians do.

References

  1. Owen, R. (1849). A History of British Fossil Reptiles, Part I. 1-328
  2. Jouve, S. (2004). Etude des crocodyliformes fini Crétace−Paléogène du Bassin de Oulad Abdoun (Maroc) et comparaison avec les faunes africaines contemporaines: systématique, phylogénie et paléobiogéographie. Ph.D. thesis. 652 pp. Muséum National d’Histoire Naturelle de Paris, Paris.
  3. Delfino, M.; Piras, P.; Smith, T. (2005). "Anatomy and phylogeny of the gavialoid crocodylian Eosuchus lerichei from the Paleocene of Europe". Acta Palaeontologica Polonica. 50: 565–580.
  4. 1 2 Brochu, C. A. (2007). "Systematics and taxonomy of Eocene tomistomine crocodylians from Britain and Northern Europe". Palaeontology . 50 (4): 917–928. Bibcode:2007Palgy..50..917B. doi: 10.1111/j.1475-4983.2007.00679.x .
  5. 1 2 Swinton, W. E. (1937). The Crocodile of Maransart (Dollosuchus dixoni [Owen]). Mémoire 80: 3-46
  6. Piras, P.; Delfino, M.; Del Favero, L.; Kotsakis, T. (2007). "Phylogenetic position of the crocodylian Megadontosuchus arduini and tomistomine palaeobiogeography". Acta Palaeontologica Polonica. 52 (2): 315–328.
  7. Domning, D. P.; Clark, J. M. (1993). "Jamaican Tertiary marine Vertebrata. In: R.M. Wright and E. Robinson (eds.)". Biostratigraphy of Jamaica. Geological Society of America Memoir. 182: 413–415. doi:10.1130/mem182-p413.
  8. Brochu, C. A. (1997). Phylogenetic Systematics and Taxonomy of Crocodylia. Unpublished Ph.D. thesis. 467 pp. University of Texas, Austin
  9. Brochu, C. A. (2001). Congruence between physiology, phylogenetics, and the fossil record on crocodylian historical biogeography. In: G. Grigg, F. Seebacher, and C.E. Franklin (eds.), Crocodilian Biology and Evolution, 9–28. Surrey Beatty and Sons, Sydney