Ilchunaia

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Ilchunaia
Temporal range: Late Eocene (Divisaderan-Tinguirirican)
~37.2–33.9  Ma
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Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Crocodylomorpha
Clade: Crocodyliformes
Clade: Notosuchia
Clade: Sebecosuchia
Clade: Sebecia
Family: Sebecidae
Genus: Ilchunaia
Rusconi, 1946
Type species
Ilchunaia parva
Rusconi, 1946

Ilchunaia is an extinct genus of sebecid mesoeucrocodylian. Fossils have been found from the Divisadero Largo Formation of Argentina dating back to the Late Eocene, [1] [2] [3] and a locality in Mendoza, Argentina dating back to the Oligocene. [4] [5] Little material is known from the genus, with only the anterior portion of the skull being present to study (the holotype has since been lost). [6] [7]

Contents

Taxonomy

The placement of Ilchunaia within Sebecosuchidae has been questioned in the past, and many recent phylogenetic analyses have shown the family to be entirely paraphyletic, with members most likely being basal sebecosuchians ancestral to the baurusuchids. [8] [9] [10] [11]

Related Research Articles

<span class="mw-page-title-main">Crocodylomorpha</span> Clade of reptiles

Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably more ecologically diverse than modern crocodillians. The earliest and most primitive crocodylomorphs are represented by "sphenosuchians", a paraphyletic assemblage containing small-bodied, slender forms with elongated limbs that walked upright, which represents the ancestral morphology of Crocodylomorpha. These forms persisted until the end of the Jurassic. During the Jurassic, crocodylomorphs morphologically diversified into numerous niches, with the subgroups Neosuchia and the extinct Thalattosuchia adapting to aquatic life, while some terrestrial groups adopted herbivorous and omnivorous lifestyles. Terrestrial crocodylomorphs would continue to co-exist alongside aquatic forms until becoming extinct during the Miocene.

Purranisaurus is an extinct genus of marine crocodyliform from the Middle to Late Jurassic period of Chile and Vaca Muerta of Argentina. Rusconi originally regarded Purranisaurus potens to be a plesiosaur; however, Gasparini demonstrated that it was in fact a metriorhynchid crocodyliform, and that may be a junior synonym of Metriorhynchus. It was about 3.3 m (11 ft) long.

<span class="mw-page-title-main">Madtsoiidae</span> Extinct family of snakes

Madtsoiidae is an extinct family of mostly Gondwanan snakes with a fossil record extending from early Cenomanian to late Pleistocene strata located in South America, Africa, India, Australia and Southern Europe. Madtsoiidae include very primitive snakes, which like extant boas and pythons would likely dispatch their prey by constriction. Genera include some of the longest snakes known such as Vasuki, measuring at least 11–15 metres (36–49 ft) long, and the Australian Wonambi and Yurlunggur. As a grouping of basal forms the composition and even the validity of Madtsoiidae is in a state of flux as new pertinent finds are described, with more recent evidence suggesting that it is paraphyletic as previously defined.

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.

<span class="mw-page-title-main">Notosuchia</span> Extinct suborder of reptiles

Notosuchia is a suborder of primarily Gondwanan mesoeucrocodylian crocodylomorphs that lived during the Jurassic and Cretaceous. Some phylogenies recover Sebecosuchia as a clade within Notosuchia, others as a sister group ; if Sebecosuchia is included within Notosuchia its existence is pushed into the Middle Miocene, about 11 million years ago. Fossils have been found from South America, Africa, Asia, and Europe. Notosuchia was a clade of terrestrial crocodilians that evolved a range of feeding behaviours, including herbivory (Chimaerasuchus), omnivory (Simosuchus), and terrestrial hypercarnivory (Baurusuchus). It included many members with highly derived traits unusual for crocodylomorphs, including mammal-like teeth, flexible bands of shield-like body armor similar to those of armadillos (Armadillosuchus), and possibly fleshy cheeks and pig-like snouts (Notosuchus). The suborder was first named in 1971 by Zulma Gasparini and has since undergone many phylogenetic revisions.

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

Baurusuchidae is a Gondwanan family of mesoeucrocodylians that lived during the Late Cretaceous. It is a group of terrestrial hypercarnivorous crocodilians from South America and possibly Pakistan. Baurusuchidae has been, in accordance with the PhyloCode, officially defined as the least inclusive clade containing Cynodontosuchus rothi, Pissarrachampsa sera, and Baurusuchus pachecoi. Baurusuchids have been placed in the suborder Baurusuchia, and two subfamilies have been proposed: Baurusuchinae and Pissarrachampsinae.

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

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

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<i>Langstonia</i> Extinct species of reptile

Langstonia is an extinct genus of notosuchian crocodylomorph of the family Sebecidae. It lived in the middle Miocene, in the "Monkey Beds" of the Colombian Villavieja Formation. Langstonia was named in 2007 by Alfredo Paolillo and Omar Linares for fossils originally described by Langston in 1965 as Sebecus huilensis. Thus, the type species is L. huilensis.

Trematochampsidae is an extinct family of mesoeucrocodylian crocodyliforms. Fossils are present from Madagascar, Morocco, Niger, Argentina, and Brazil. Possible trematochampsids have been found from Spain and France, but classification past the family level is indeterminant. The trematochampsids first appeared during the Barremian stage of the Early Cretaceous and became extinct during the late Maastrichtian stage of the Late Cretaceous.

Ayllusuchus is an extinct genus of sebecid mesoeucrocodylian. Fossils have been found in the Lumbrera Formation of Argentina.

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

Bergisuchus is an extinct genus of small sebecosuchian mesoeucrocodylian known primarily from the Eocene Messel Pit in Germany. Few fossils of Bergisuchus have been discovered, only a single incomplete snout, a few partial lower jaws and some teeth. Despite being fragmentary, the jaw bones are enough to indicate that Bergisuchus had a short, deep, narrow snout and serrated teeth, quite unlike the broad flat snouts of modern crocodylians.

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

Bretesuchus is an extinct genus of sebecosuchian mesoeucrocodylian within the family Sebecidae known from northwestern Argentina. It was a large apex predator.

Eremosuchus is an extinct genus of sebecosuchian mesoeucrocodylian. Fossils have been found from El Kohol, Algeria of Eocene age. It had serrated, ziphodont teeth.

Lomasuchus is an extinct genus of peirosaurid notosuchian known from the Late Cretaceous of Neuquén Province, western central Argentina. It contains a single species, Lomasuchus palpebrosus.

Meridiosaurus is an extinct genus of mesoeucrocodylian that is a possible member of the family Pholidosauridae. Remains have been found in the Late Jurassic Tacuarembó Formation in Tacuarembó, Uruguay. The genus was described in 1980 on the basis of a partial rostrum that included the premaxillae and most of the maxillae. The assignment to Pholidosauridae is considered doubtful by some authors, but a 2011 redescription and phylogenetic analysis confirmed the pholidosaurid classification of Meridiosaurus.

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

Sebecus is an extinct genus of sebecid crocodylomorph from Eocene of South America. Like other sebecosuchians, it was entirely terrestrial and carnivorous. The genus is currently represented by two species, the type S. icaeorhinus and S. ayrampu. Several other species have been referred to Sebecus, but were later reclassified as their own genera.

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

Sebecidae is an extinct family of prehistoric terrestrial sebecosuchian crocodylomorphs, known from the Late Cretaceous and Cenozoic of Europe and South America. They were the latest surviving group of non-crocodilian crocodylomorphs.

Sebecosuchia is an extinct group of mesoeucrocodylian crocodyliforms that includes the families Sebecidae and Baurusuchidae. The group was long thought to have first appeared in the Late Cretaceous with the baurusuchids and become extinct in the Miocene with the last sebecids, but Razanandrongobe pushes the origin of Sebecosuchia to the Middle Jurassic. Fossils have been found primarily from South America but have also been found in Europe, North Africa, Madagascar, and the Indian subcontinent.

<span class="mw-page-title-main">Ziphosuchia</span> Extinct clade of reptiles

Ziphosuchia is a clade of mesoeucrocodylian crocodyliforms that includes notosuchians and sebecosuchians.

References

  1. Ilchunaia at Fossilworks.org
  2. Paolillo, Alfredo; and Linares, Omar J. (2007). Nuevos cocodrilos Sebecosuchia del Cenozoico Suramericano (Mesosuchia: Crocodylia). Paleobiologia Neotropical3: 1–25.
  3. Turner, A. H. and Calvo, J. O. (2005). A new sebecosuchian crocodyliform from the Late Cretaceous of Patagonia. Journal of Vertebrate Paleontology25(1):87–98.
  4. Rusconi, C. (1946). Ave y reptil oligocenos de Mendoza. Bolletín Paleontológico (Buenos Aires)21:1–3.
  5. Langston, W. J. (1956). The Sebecosuchia: cosmopolitan crocodilians? American Journal of Science254:605–614.
  6. Gasparini, Z., Fernández, M. and Powell, J. (1993). New Tertiary Sebecosuchians (Crocodylomorpha) from South America: Phylogenetic Implications. Hististorical Biology7:1-19.
  7. Gasparini, Z. (1972). Los Sebecosuchia (Crocodilia) del territorio argentino. Consideraciones sobre su “status” taxonómico. Ameghiniana9(1): 23-34.
  8. Busbey III, A. B. (1986). New material of Sebecus cf. huilensis (Crocodilia: Sebecosuchia) from the Miocene La Venta Formation of Colombia. Journal of Vertebrate Paleontology6(1):20-27.
  9. Gasparini, Z., Fernández, M. and Powell, J. (1993). New Tertiary Sebecosuchians (Crocodylomorpha) from South America: Phylogenetic Implications. Hististorical Biology7:1-19.
  10. Ortega, F., Buscalioni, A. D. and Gasparini, Z. (1996). Reinterpretation and new denomination of Atacisaurus crassiporatus (Middle Eocene; Issel, France) as cf. Iberosuchus (Crocodylomorpha, Metasuchia). Geobios29:353–364.
  11. Ortega, F., Gasparini, Z., Buscalioni, A. D., and Calvo, J. O. (2000). A new species of Araripesuchus (Crocodylomorpha, Mesoeucrocodylia) from the Lower Cretaceous of Patagonia (Argentina). Journal of Vertebrate Paleontology20:57–76.