Allodaposuchus

Allodaposuchus is an extinct genus of crocodyliforms that includes four species that lived in what is now southern Europe during the Campanian and Maastrichtian stages of the Late Cretaceous. Although generally classified as a non-crocodylian crocodylomorph, it is sometimes placed as one of the earliest true crocodylians. Allodaposuchus is one of the most common Late Cretaceous crocodylomorphs from Europe, with fossils known from Spain, Romania, and France.

Allodaposuchus
Temporal range: Campanian-Maastrichtian
~84.9–66.043 Ma
Allodaposuchus precedens
A. precedens skull
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Family: Allodaposuchidae
Genus: Allodaposuchus
Nopcsa, 1928
Type species
Allodaposuchus precedens
Nopcsa, 1928
Species
  • A. hulki Blanco et al., 2015[1]
  • A. palustris Blanco et al., 2014[2]
  • A. precedens Nopcsa 1928[3]

Description

Allodaposuchus BW
Restoration of A. precedens

Like many other Cretaceous crocodylomorphs, Allodaposuchus has a relatively small body size compared to living crocodylians. The largest known specimen of Allodaposuchus belongs to an individual that was probably around 3 metres (9.8 ft) long.[4] Although the shape varies between species, in general Allodaposuchus has a short, flattened, and rounded skull. Allodaposuchus precedens has a brevirostrine or "short-snouted" skull with a snout about the same length as the skull table (the region of the skull behind the eye sockets) and A. subjuniperus has a mesorostrine or "middle-snouted" skull with a snout that is longer than the skull table.[4][5] The main feature that distinguishes Allodaposuchus species from other related crocodylomorphs is the orientation of a groove at the back of the skull called the cranioquadrate passage; unlike the cranioquadrate passages of other crocodylomorphs, which are only visible at the back of the skull, the cranioquadrate passage of Allodaposuchus is visible when the skull is viewed from the side.[6]

At least one species of Allodaposuchus, A. hulki, may have adaptations that would have allowed it to live on land for extended periods of time. A. hulki has large sinuses in its skull that are not seen in any other crocodylian living or extinct and may have aided it in hearing out of water, as well as lightening the skull. Moreover, A. hulki has well-developed muscle attachments on its scapula, humerus, and ulna bones that would have allowed the forelimbs to have been held in a semi-erect stance suitable for walking over land. Remains of A. hulki come from interbedded sandstones and marls that, based on the presence of charophyte algae, likely formed in ephemeral ponds in a large floodplain far from permanent bodies of water like lakes or rivers. A. hulki may therefore have spent much of its time out of water, travelling between these ponds for food.[1]

History of study

There are four described species Allodaposuchus. The type species of Allodaposuchus, A. precedens, was named by Hungarian paleontologist Franz Nopcsa in 1928 from Vălioara, Romania.[3] Nopcsa found bone fragments in a deposit of the Hațeg Basin that dates back to the late Maastrichtian stage – the very end of the Late Cretaceous. Several partial skulls from Spain and France were attributed to A. precedens in 2001.[7] Some of these skulls came from Campanian-age deposits slightly older than those in Romania, meaning that the species must have persisted for about 5 million years.[4] In 2013 a second species of Allodaposuchus, A. subjuniperus, was named on the basis of a skull from the late-Maastrichtian Conquès Formation, part of the Tremp Group, in the province of Huesca, Spain. The skull was found underneath a juniper tree whose roots had grown between the bones, hence the species name subjuniperus or "under juniper" in Latin.[4] The 2013 study also proposed that the French and Spanish fossils assigned to A. precedens in 2001 might actually represent a new unnamed species of Allodaposuchus currently identified as Allodaposuchus sp. A study published in 2005 had suggested that these fossils belong to several different genera of crocodylomorphs and that the original Romanian material is too fragmentary to assign to its own genus, making Allodaposuchus a nomen dubium or "dubious name".[8] However, the 2013 study reaffirmed the Romanian material's distinctiveness from other European Cretaceous crocodylomorphs and therefore reaffirmed the validity of Allodaposuchus as a genus.[4]

In 2014, A. palustris was described from a partial skull and other skeletal fragments found in Maastrichtian age sediments of the Tremp Formation in a fossil locality called Fumanya Sud in the southern Pyrenees.[2] These remains allowed for the first detailed description of the postcranial (non-skull) anatomy of Allodaposuchus. A fourth species of Allodaposuchus, A. hulki, was named in 2015 and also came from the Tremp Formation, although this time in a locality called Casa Fabà. The species is named after the Hulk from Marvel Comics, in reference to features on the bones that suggest it had strong muscles.[1]

Relationships

Allodaposuchus palustris
jaw fragments and teeth of A. palustris
Allodaposuchus palustris skeletal diagram
Skeletal diagram showing known remains of A. palustris

Allodaposuchus is one of the earliest members of the Crocodylia clade, the most exclusive group including all modern crocodylians. The ancestors of Allodaposuchus and other crocodylians were part of a larger evolutionary group called Eusuchia that originated in the Early Cretaceous. Allodaposuchus is part of an evolutionary radiation of eusuchians that happened later in the Cretaceous as they spread to multiple continents.

When Franz Nopcsa named Allodaposuchus, he proposed that it was a close relative of Leidyosuchus, a crocodylian from Canada. However, Nopsca could only base this assignment on a few fragments of bone. After more complete material was uncovered from Spain and France, Allodaposuchus was reinterpreted as a non-crocodylian eusuchian in 2001. The 2001 study recognized a close relationship between Allodaposuchus and Hylaeochampsa, a eusuchian from the Early Cretaceous of England. A 2010 phylogenetic analysis supported a relationship similar to Nopsca's by placing Allodaposuchus within Alligatoroidea, a group of crocodylians that includes modern-day alligators and Leidyosuchus. The most recent phylogenetic analyses of Allodaposuchus – published alongside the descriptions of A. palustris in 2014 and A. hulki in 2015 – place it within Crocodylia but outside Alligatoroidea as a sister taxon (closest relative) of the clade Brevirostres, which includes Alligatoroidea and Crocodyloidea, the group including crocodiles and their closest extinct relatives. According to these studies Allodaposuchus is more closely related to Alligatoroidea and Crocodyloidea than it is to the third major group of living crocodylians, Gavialoidea, which includes modern gharials. Among extinct groups, Allodaposuchus is most closely related to the genus Borealosuchus, which existed in North America from the Late Cretaceous to the Eocene, and the family Planocraniidae, which existed in North America, Europe, and Asia from the Paleocene to the Eocene.[1]

The 2015 analysis also indicated a close relationship between Allodaposuchus species and a genus called Arenysuchus, regarded as a crocodyloid in earlier analyses. Like Al. palustris and Al. hulki, Arenysuchus comes from the Tremp Formation of Spain, although from a different locality called Elías. Arenysuchus fell within the Allodaposuchus clade, being more closely related to A. hulki and A. precedens than is A. palustris, raising the possibility that Allodaposuchus is a polyphyletic taxon (i.e., not a true clade) . The authors of the analysis proposed the name Allodaposuchia for the clade containing Arenysuchus and Allodaposuchus species. Below is a cladogram from that analysis:[1]

Eusuchia

Hylaeochampsidae

Crocodylia

Gavialoidea

Planocraniidae

Borealosuchus spp.

"Allodaposuchia"

Allodaposuchus palustris

Allodaposuchus subjuniperus

Arenysuchus gascabadiolorum

Allodaposuchus hulki

Allodaposuchus precedens

Brevirostres

Alligatoroidea

Crocodyloidea

References

  1. ^ a b c d e Blanco et al., 2015, p.10
  2. ^ a b Blanco et al., 2014, p.7
  3. ^ a b Nopcsa, 1928
  4. ^ a b c d e Puértolas et al., 2014, p.93
  5. ^ Martin, 2010
  6. ^ Delfino et al., 2008
  7. ^ Buscalioni et al., 2001
  8. ^ Martin & Buffetaut, 2005

Bibliography

Aegyptosuchidae

Aegyptosuchidae is an extinct family of eusuchian crocodyliforms from the Cretaceous period of Africa. They are characterized by their large size and flat heads. The family includes two genera, Aegyptosuchus and Aegisuchus.

Agaresuchus

Agaresuchus is an extinct genus of allodaposuchid once known as "Allodaposuchus" subjuniperus.

In 2013 a second species of Allodaposuchus, A. subjuniperus, was named on the basis of a skull from the late-Maastrichtian Conquès Formation, part of the Tremp Group, in the province of Huesca, Spain. The skull was found underneath a juniper tree whose roots had grown between the bones, hence the species name subjuniperus or "under juniper" in Latin. In 2016, the species was renamed to Agaresuchus subjuniperus The 2013 study also proposed that the French and Spanish fossils assigned to A. precedens in 2001 might actually represent a new unnamed species of Allodaposuchus currently identified as Allodaposuchus sp.

Allodaposuchidae

Allodaposuchidae is an extinct clade of basal eusuchians that lived in southern Europe during the Late Cretaceous (Santonian-Maastrichtian).

Batrachomimus

Batrachomimus is an extinct genus of neosuchian crocodyliform known from the Late Jurassic of northeastern Brazil. It contains a single species, Batrachomimus pastosbonensis, which was first described and named by Felipe C. Montefeltro, Hans C. E. Larsson, Marco A. G. de França and Max C. Langer in 2013. It is known from a nearly complete skull, osteoderms and limb bones. Batrachomimus belongs to the family Paralligatoridae and predates all other members of the family and its immediate sister group, Eusuchia, by 30 million years.

Brillanceausuchus

Brillanceausuchus is an extinct genus of atoposaurid crocodylomorph. Fossils have been found in Early Cretaceous–age rocks of Cameroon. The genus is notable for the position of the secondary choana within its palate. Parts of the pterygoid bones make up the rostral margin of the choana and thus separate it from the palatines, a feature also seen in the more advanced neosuchian suborder Eusuchia. This characteristic was once thought to be characteristic of Eusuchia, but its presence in Brillanceausuchus suggests that the trait is homoplasic, thus making the evolution of the position of the choana within crocodilians more complex than previously thought.

Coelosuchus

Coelosuchus is an extinct genus of goniopholidid mesoeucrocodylian. Fossils have been found from the Graneros Shale of the Benton Group in Wyoming, and are of Cenomanian age. It was slightly over 1 meter in length.

Dinosaur Planet (TV series)

Dinosaur Planet is a four-part American nature documentary that aired on the Discovery Channel as a special-two night event on December 14 and 16, 2003. It is hosted by paleontologist Scott Sampson and narrated by actor Christian Slater. It was released on DVD as a two-disc pack on February 17, 2004, and was also released on VHS around the same time.

The format is similar to Discovery's earlier series When Dinosaurs Roamed America. Each episode tells a fictionalized account of a dinosaur from the Late Cretaceous period. The animals are recreated with computer-generated imagery and composited into present-day filmed locations that approximate prehistoric Earth. Periodic interludes (three in each episode) feature Scott Sampson explaining the scientific findings behind the story, also similar to When Dinosaurs Roamed America, but has improved in quality.

Dinosaurs of Romania

The dinosaurs of Romania are exclusively Cretaceous. Lowermost Cretaceous dinosaurs come from a bauxite mine in the Bihor County (northwest Romania) that has yielded thousands of disarticulated bones. Uppermost Cretaceous dinosaurs have been known from the Hațeg Basin (south Transylvania) since the end of the 19th century, mostly as bone concentrations (fossiliferous pockets); more recently, nests with dinosaur eggs, including hatchlings, have been found in Hațeg. Although separated by a gap of approximately 60 million years, the two dinosaur faunas from Romania share some common features: predominance of ornithopods, absence of large theropods (although the Maastrichtian Hațeg assemblage has several small theropods), and, in general, the small size of the individuals (see also insular dwarfism).

The discovery of dinosaur bones in a bauxite mine at Cornet-Brusturi, near Oradea (Bihor County) was made accidentally by two miners in 1978 during ore exploitation. Almost at the same time, research in the already known Uppermost Cretaceous dinosaur-bearing deposits from the Hațeg Basin were restarted by Dan Grigorescu, after an interruption of more than 60 years, since Franz Nopcsa’s work in the region.

The Berriasian bauxite deposits at Cornet have yielded approximately 10,000 bones and bone fragments, mainly from ornithopod dinosaurs and rarer pterosaurs. The region was located to the east of the Piemont-Liguria Ocean, and during the Early Cretaceous formed an archipelago of coral and volcanic islands, not too dissimilar to today's Indonesia or the Caribbean. As the Apulian Plate moved northwest towards the end of the Cretaceous and the beginning of the uplift of the Alpide belt, the offshore Hațeg Island was formed at the rim of the shrinking Tethys Ocean.

Among the species that lived here are: Zalmoxes, Telmatosaurus, Balaur, Rhabdodon, Magyarosaurus and Struthiosaurus. Other prehistoric creatures that lived among them, without being dinosaurs are: Allodaposuchus and Hatzegopteryx.

Eusuchia

The Eusuchia ("true crocodiles") are a clade of crocodylomorphs that first appears in the Early Cretaceous with Hylaeochampsa. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survived the K-T extinction. Since the other two clades died out 35 and 11 million years ago, all living crocodilian species are eusuchians, as are many extinct forms.

Ischyrochampsa

Ischyrochampsa is an extinct genus of Late Cretaceous mesoeucrocodylian belonging to the eusuchian clade Allodaposuchidae. Fossils of the type species I. meridionalis are late Campanian in age and were found in the commune of Saint-Estève-Janson in Bouches-du-Rhône, France. Material is also known from Spain. At an estimated length of over 4 metres (13 ft), Ischyrochampsa was a large mesoeucrocodylian. It was named and described in 1995.Ischyrochampsa was first classified as a trematochampsid, but was removed from the group by subsequent studies. In their description of Allodaposuchus remains from southern France, Martin and his colleagues treated the genus as a possible junior synonym of Allodaposuchus.

Lohuecosuchus

Lohuecosuchus (Lo Hueco crocodile) is an extinct genus of crocodyliforms related to the current crocodiles. It lived during the Late Cretaceous (late Campanian to early Maastrichtian) in what is now Spain and southern France. It is a genus closely related to Allodaposuchus, a crocodile that lived in what is now Romania. It was both synchronic and sympatric with another allodaposuchid species, Agaresuchus fontisensis. Fossils of the genus have been recovered from the Villalba de la Sierra Formation at Lo Hueco.

Matheronodon

Matheronodon (meaning "Matheron tooth") is a genus of rhabdodontid ornithopod dinosaur from the Late Cretaceous of France. The genus contains a single species, M. provincialis, which is known from a single maxilla and associated teeth. It was named by Pascal Godefroit and colleagues in 2017. The teeth of Matheronodon are large but few in number. The teeth are also in an unusual arrangement, emerging alternatingly from one of a pair of fused tooth sockets in its mouth. In life, the teeth would have functioned like a pair of scissors, allowing Matheronodon to feed on the tough leaves of monocot plants.

Nannosuchus

Nannosuchus (meaning "dwarf crocodile") is an extinct genus of goniopholidid mesoeucrocodylian from the Berriasian of England.

Neosuchia

Neosuchia is a clade within Mesoeucrocodylia that includes all modern extant crocodilians and their closest fossil relatives. It is defined as the most inclusive clade containing all crocodylomorphs more closely related to Crocodylus niloticus (the Nile Crocodile) than to Notosuchus terrestris. Neosuchia is very diverse and may be polyphyletic, as the clade has undergone many revisions since it was first named in 1988. Neosuchians first appear in the Early Jurassic with the earliest known goniopholid Calsoyasuchus, which lived during the Sinemurian and Pliensbachian stages.

Paluxysuchus

Paluxysuchus is an extinct genus of neosuchian crocodyliform known from the Early Cretaceous Twin Mountains Formation (late Aptian stage) of north-central Texas. It contains a single species, Paluxysuchus newmani. Paluxysuchus is one of three crocodyliforms known from the Early Cretaceous of Texas, the others being Pachycheilosuchus and an unnamed species referred to as the "Glen Rose Form". Paluxysuchus has a long, flat skull that is probably transitional between the long and narrow skulls of many early neosuchians and the short and flat skulls of later neosuchians.

Paralligatoridae

Paralligatoridae is an extinct family of neosuchian crocodyliforms that existed during the Jurassic and Cretaceous periods. It includes the genera Paralligator, Brillanceausuchus, Kansajsuchus, Shamosuchus, Scolomastax, Sabresuchus, Rugosuchus, Batrachomimus and Wannchampsus, as well as the yet-unnamed "Glen Rose form".

Susisuchus

Susisuchus is an extinct genus of neosuchian mesoeucrocodylian crocodyliform from the Early Cretaceous of Brazil. Fossils have been found from the Nova Olinda Member of the Aptian-age Crato Formation in the Araripe and Lima Campos Basins of northeastern Brazil. Named in 2003, Susisuchus is the sole member of the family Susisuchidae, and is closely related to the clade Eusuchia, which includes living crocodilians. The type species is S. anatoceps, known from a single partial articulated skeleton that preserves some soft tissue. A second species, S. jaguaribensis, was named in 2009 from fragmentary remains.

Symptosuchus

Symptosuchus is an extinct genus of goniopholidid mesoeucrocodylian. It is known from the Late Cretaceous of Argentina. Argentine paleontologist Florentino Ameghino named the genus in 1899, along with the type species S. contortidens. It was formally described by Carlos Rusconi in 1934.

Extinct crocodilian species

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