Gavialosuchus

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Gavialosuchus
Temporal range: Early Miocene, 20.4–16  Ma [1]
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Gavialosuchus eggenburgensis 4423.jpg
Gavialosuchus eggenburgensis skull
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Family: Gavialidae
Genus: Gavialosuchus
Toula and Kail, 1885
Type species
Gavialosuchus eggenburgensis
Toula and Kail, 1885

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.

Contents

Taxonomy

The type species, G. eggenburgensis, is known from the early Miocene of Austria. Two other species - G. americanus and G. carolinensis - have since been reclassified to other genera.

Myrick Jr. (2001) proposed synonymizing Gavialosuchus americanus with Thecachampsa antiqua . [2] Piras et al. (2007) advocated transferring both G. americanus and G. carolinensis to Thecachampsa as distinct species of the latter genus, however. [3] Jouve et al. (2008) retained G. americanus in Gavialosuchus and found it to be the sister group of G. eggenburgensis (G. carolinensis was not discussed). [4] However, Jouve et al. (2008) didn't test Thecachampsa antiqua in their phylogenetic analysis. Shan et al. (2009) found that G. americanus and G. eggenburgensis are not sister taxa. However, they didn't include T. antiqua and G. carolinensis in their analysis. [5] Christopher A. Brochu and Glenn W. Storrs (2012) tested all four species, along with other crocodyloids, and found relatively strong support for Piras et al. (2007) suggestion. [6] Weems (2018) agreed with Piras et al. (2007) and Brochu & Storrs (2012) at americanus and carolinensis are part of Thecachampsa. [7]

Below is a cladogram based morphological studies comparing skeletal features that shows Gavialosuchus as a member of Tomistominae, related to the false gharial: [8]

Crocodylidae

Based on morphological studies of extinct taxa, the tomistomines (including the living false gharial) were long thought to be classified as crocodiles and not closely related to gavialoids. [9] However, recent molecular studies using DNA sequencing have consistently indicated that the false gharial (Tomistoma) (and by inference other related extinct forms in Tomistominae) actually belong to Gavialoidea. [10] [11] [12] [13] [14] [15] [16]

Below is a cladogram from a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data that shows Gavialosuchus as a gavialid, related to both the gharial and the false gharial: [15]

Gavialidae

Ecology

Unlike its modern fresh water relatives, Gavialosuchus was an estuarine and coastal water crocodilian, living in shallow marine waters.

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.

<span class="mw-page-title-main">False gharial</span> Species of crocodilian

The false gharial, also known by the names Malayan gharial, Sunda gharial and tomistoma, is a freshwater crocodilian of the family Gavialidae native to Peninsular Malaysia, Borneo, Sumatra and Java. It is listed as Endangered on the IUCN Red List, as the global population is estimated at around 2,500 to 10,000 mature individuals.

<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.

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.

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

Dollosuchus is an extinct monospecific genus of tomistomine crocodilian originally named as a species of Gavialis. It is a basal form possibly related to Kentisuchus, according to several phylogenetic analyses that have been conducted in recent years, and is the oldest known tomistomine to date. Fossils have been found from Belgium and the United Kingdom. It had large supratemporal fenestrae in relation to its orbits, similar to Kentisuchus and Thecachampsa.

<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.

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

Planocrania is an extinct genus of eusuchian crocodyliforms from what is now China. Two species are currently known to belong to the genus.

<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.

<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.

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.

<span class="mw-page-title-main">Brevirostres</span> Taxon of reptiles

Brevirostres is a paraphyletic group of crocodilians that included alligatoroids and crocodyloids. Brevirostres are crocodilians with small snouts, and are distinguished from the long-snouted gharials. It is defined phylogenetically as the last common ancestor of Alligator mississippiensis and Crocodylus niloticus and all of its descendants. This classification was based on morphological studies primarily focused on analyzing skeletal traits of living and extinct fossil species, and placed the gharials outside the group due to their unique skull structure, and can be shown in the simplified cladogram below:

<span class="mw-page-title-main">Planocraniidae</span> Extinct family of reptiles

Planocraniidae is an extinct family of eusuchian crocodyliforms known from the Paleogene of Asia, Europe and North America. The family was coined by Li in 1976, and contains three genera, Boverisuchus, Duerosuchus and Planocrania. Planocraniids were highly specialized crocodyliforms that were adapted to living on land. They had extensive body armor, long legs, and blunt claws resembling hooves, and are sometimes informally called "hoofed crocodiles".

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

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