Rhamphosuchus

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Rhamphosuchus
Temporal range: 5.333–2.588  Ma
Rhamphosuchus crassidens.jpg
Life restoration
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: Gavialinae
Genus: Rhamphosuchus
Falconer & Cautley, 1840
Type species
Rhamphosuchus crassidens
Falconer & Cautley, 1840

Rhamphosuchus ("Beak crocodile") is an extinct genus of gavialid crocodylians. It lived during the Pliocene and its fossils have been found in two regions; the Siwalik Hills of Pakistan and India as well as the Sindh region of Pakistan. Its type species is Rhamphosuchus crassidens, which is only known from incomplete sets of fossils, mostly teeth and skulls. Four species traditionally placed in the genus Gavialis may be included as well. [1]

Contents

Overview

Rhamphosuchus crassidens jaws Rhamphosuchus crassidens 7.JPG
Rhamphosuchus crassidens jaws
An 1868 illustration of specimens of R. crassidens (top and center) compared to other crocodylian fossils from the Sewalik Hills Sewalik crocodylians.jpg
An 1868 illustration of specimens of R. crassidens (top and center) compared to other crocodylian fossils from the Sewalik Hills

Traditionally, many palaeontologists estimated that it was one of the largest, if not the largest crocodylian that ever lived, reaching an estimated length of 15 to 18 m (49 to 59 ft). [2] However, a more recent study suggests that the animal may have been 8–11 m (26 to 36 ft) in length, and therefore is not the largest known crocodylian. [3] Another crocodylian, Purussaurus , from the Miocene of Peru and Brazil, is known from an equally incomplete fossil set. It is estimated to have been similar in length to the initial estimates at approximately 10.9 m (about 35 ft). However, this would mean that it would have been somewhat larger in size if the more recent size estimates for Rhamphosuchus are correct. If the most recent estimate is correct, then several other extinct crcoodilians and crocodylomorphs likely surpassed Rhamphosuchus in weight , such as the Late Cretaceous alligatoroid Deinosuchus , the Early Cretaceous pholidosaurid Sarcosuchus and the Miocene gavialid Gryposuchus , at 10.6 m, 9.5 m and 10 m, respectively.

Rhamphosuchus was previously regarded as a close relative of the modern false gharial within the subfamily Tomistominae. However, Tomistominae in its traditional sense is now known to be paraphyletic, and a 2022 study by Iijima and colleagues recovered Rhamphosuchus as a derived member of the subfamily Gavialinae instead. [4] Rhamphosuchus probably had a more generalized predatory diet than the piscivory of other "tomistomines". [3]

See also

Related Research Articles

<span class="mw-page-title-main">Gavialinae</span> Subfamily of gharial crocodylians

Gavialinae is a subfamily of large semiaquatic crocodilian reptiles, resembling crocodiles, but with much thinner snouts. Gavialinae is one of the two major subfamilies within the family Gavialidae - the other being the subfamily Tomistominae, which contains the false gharial and extinct relatives.

<span class="mw-page-title-main">Gavialidae</span> Family of gharial crocodylians

Gavialidae is a family of large semiaquatic crocodilians with elongated, narrow snouts. Gavialidae consists of two living species, the gharial and the false gharial, both occurring in Asia. Many extinct members are known from a broader range, including the recently extinct Hanyusuchus. Gavialids are generally regarded as lacking the jaw strength to capture the large mammalian prey favoured by crocodiles and alligators of similar size so their thin snout is best used to catch fish, however the false gharial has been found to have a generalist diet with mature adults preying upon larger vertebrates, such as ungulates.

<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.

<i>Tomistoma</i> Genus of crocodilians

Tomistoma is a genus of gavialid crocodilians. They are noted for their long narrow snouts used to catch fish, similar to the gharial. Tomistoma contains one extant (living) member, the false gharial, as well as potentially several extinct species: T. cairense, T. lusitanicumT. coppensi, and T. dowsoni. However, these species may need to be reclassified to different genera as studies have shown them to be paraphyletic, for example: previously assigned species T. taiwanicus from Taiwan, is reclassified to the genus Toyotamaphimeia, and T. dowsoni should be excluded from Tomistoma based on phylogenetic analysis.

<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. taiwanicus 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.

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>Gryposuchus</i> Extinct genus of gavialoid crocodilian

Gryposuchus is an extinct genus of gavialid crocodilian. Fossils have been found from Argentina, Colombia, Venezuela, Brazil and the Peruvian Amazon. The genus existed during the Miocene epoch. One recently described species, G. croizati, grew to an estimated length of 10 metres (33 ft). Gryposuchus is the type genus of the subfamily Gryposuchinae, although a 2018 study indicates that Gryposuchinae and Gryposuchus might be paraphyletic and rather an evolutionary grade towards the gharial.

Ikanogavialis is an extinct genus of gavialid crocodilian. Fossils have been found in the Urumaco Formation in Urumaco, Venezuela and the Solimões Formation of Brazil. The strata from which remains are found are late Miocene in age, rather than Pliocene as was once thought. A possible member of this genus survived into the Late Holocene on Muyua or Woodlark Island in Papua New Guinea.

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

Piscogavialis is an extinct monospecific genus of gryposuchine gavialid crocodylian. The only species yet known is P. jugaliperforatus. Fossils of Piscogavialis have been found from the Mio-Pliocene Pisco Formation of the Sacaco Basin in southern Peru in 1998, where it coexisted with the much smaller gavialid Sacacosuchus.

Siquisiquesuchus is an extinct genus of gavialid crocodilian. It is known from cranial remains and a few postcranial bones found in Miocene-age rocks of the Castillo Formation in northwestern Venezuela.

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

Penghusuchus is an extinct genus of gavialid crocodylian. It is known from a skeleton found in Middle to Upper Miocene rocks of Penghu Island, off Taiwan. The taxon was described in 2009 by Shan and colleagues; the type species is P. pani. It may be related to two other fossil Asian gavialids: Toyotamaphimeia machikanensis of Japan and Hanyusuchus sinensis of South China. It was a medium-sized gavialid with an estimated total length of 4.5 metres (15 ft).

<span class="mw-page-title-main">Crocodyloidea</span> Superfamily of crocodiles

Crocodyloidea is one of three superfamilies of crocodilians, the other two being Alligatoroidea and Gavialoidea, and it includes the crocodiles. Crocodyloidea may also include the extinct Mekosuchinae, native to Australasia from the Eocene to the Holocene, although this is disputed.

Melitosaurus is an extinct genus of gavialid crocodylian discovered in Gozo, Malta in Early Miocene Aquitanian stage marine limestone rock in 1850. It is related to the extant (living) False gharial and a member of the same subfamily Tomistominae, as shown in the cladogram below:

Gryposuchinae is an extinct subfamily of gavialid crocodylians. Gryposuchines lived mainly in the Miocene of South America. However, "Ikanogavialis" papuensis may have survived more recently, into the Late Pleistocene/Holocene. Most were long-snouted coastal forms. The group was named in 2007 and includes genera such as Gryposuchus and Aktiogavialis, although a 2018 study indicates that the group might be paraphyletic and rather an evolutionary grade towards the gharial.

<span class="mw-page-title-main">Gavialoidea</span> Superfamily of large reptiles

Gavialoidea is one of three superfamilies of crocodylians, the other two being Alligatoroidea and Crocodyloidea. Although many extinct species are known, only the gharial Gavialis gangeticus and the false gharial Tomistoma schlegelii are alive today, with Hanyusuchus having become extinct in the last few centuries.

<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>Astorgosuchus</i> Extinct genus of reptiles

Astorgosuchus is an extinct monospecific genus of crocodilian, closely related to true crocodiles, that lived in Pakistan during the late Oligocene period. This crocodile may have reached lengths of up to 8 m (26 ft) and is known to have preyed on many of the large mammals found in its environment. Bite marks of a large crocodile have been found on the bones of juvenile Paraceratherium, however if these were left by Astorgosuchus cannot be said with certainty. The genus contains a single species, Astorgosuchus bugtiensis, which was originally named as a species of Crocodylus in 1908 and was moved to its own genus in 2019.

Gavialis pachyrhynchus is an extinct species of gavialid from the Miocene of India. Although only known from fragmentary jaw material, the size of this material is substantially larger than comparable bones in large gharials.

Sacacosuchus is an extinct monospecific genus of marine gavialid that lived along the coast of the south-east Pacific from approximately 19 to 6.3 million years ago. Its fossils have been found in the Chilcatay and Pisco Formations of Peru, where it coexisted with the much larger Piscogavialis. Based on its skull, Sacacosuchus was most likely a generalist feeder with an estimated total body length of 4.32 m (14.2 ft). Its extinction is thought to have been caused by a combination of factors including falling sea levels and global cooling.

References

  1. Martin, J. E. (2018). "The taxonomic content of the genus Gavialis from the Siwalik Hills of India and Pakistan" (PDF). Papers in Palaeontology. 5 (3): 483–497. doi:10.1002/spp2.1247.
  2. Heilprin, Angelo (1974). The Geographical and Geological Distribution of Animals: The International Science Series Vol. 57. Ayer Publishing. ISBN   0-405-05742-3.
  3. 1 2 Head, J. J. (2001). "Systematics and body size of the gigantic, enigmatic crocodyloid Rhamphosuchus crassidens, and the faunal history of Siwalik Group (Miocene) crocodylians". Journal of Vertebrate Paleontology. 21 (Supplement to No. 3): 59A. doi:10.1080/02724634.2001.10010852. S2CID   220414868.
  4. Iijima, M.; Qiao, Y.; Lin, W.; Peng, Y.; Yoneda, M.; Liu, J. (2022). "An intermediate crocodylian linking two extant gharials from the Bronze Age of China and its human-induced extinction". Proceedings of the Royal Society B: Biological Sciences. 289 (1970): 20220085. doi: 10.1098/rspb.2022.0085 . PMC   8905159 . PMID   35259993.