Entradasuchus

Entradasuchus Temporal range: Middle Jurassic
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Clade:	Crocodyliformes
Genus:	†Entradasuchus Hunt & Lockley, 1995
Species:	†E. spinosus
Binomial name
†Entradasuchus spinosus Hunt & Lockley, 1995

Entradasuchus (meaning "Entrada [Sandstone and Ranch] crocodile") is a genus of crocodyliform, an early member of the group including crocodilians. The only known specimen was found in rocks of the Middle Jurassic Entrada Sandstone of Entrada Ranch, Grand County, Utah. Middle Jurassic terrestrial tetrapods are very rare, and Entradasuchus was the first unequivocal North American Middle Jurassic nonmarine tetrapod known from body fossils when it was described (1995).^[1]

Description

Entradasuchus is based on CU-MWC 183-11, a skeleton including at least the upper surfaces of the skull, articulated armor scutes from the neck to the tail, and some limb bones, all preserved in top (dorsal) view. The exact composition of the specimen was unknown at the time of its description, because it is preserved in sandstone that is harder than the calcite that has replaced the bones, which makes preparation difficult. Additionally, much of the visible part of the skeleton is represented by mold impressions of eroded bones. The block containing the specimen weathered from canyon walls and probably came from the middle Moab Member of the Entrada Sandstone, dated to the very late middle Callovian of the Middle Jurassic. The Moab Member of the Entrada Sandstone represents an inland dune (eolian) setting.^[1]

The skull of CU-MWC 183-11 is distinguished by the width of the posterior portion. Approximately 42 pairs of scutes ran down the midline of the back. The first pair behind the skull were square, but those on the back and tail were rectangular and had short spiny projections on their posterior outside corners. These spines inspired the name of the type species: E. spinosus. CU-MWC 183-11 was not a large animal, with a skull only a few centimeters or inches long. This small size and the form of the skull could indicate it was a juvenile, but the fusion of the parietals in the skull and the generally small size of animals found in settings like the upper Entrada Sandstone suggest it was an adult. Adrian Hunt and Martin Lockley, who described Entradasuchus in 1995, classified it as Crocodyliformes incertae sedis.^[1]

The type specimen is curated at the Museum of Western Colorado in Fruita, Colorado.

References

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Pseudosuchia

Kingdom: Animalia Phylum: Chordata Class: Sauropsida Clade: Archosauria
Sauropsida see Sauropsida Archosauromorpha see Archosauromorpha Pseudosuchia see below↓

Pseudosuchia
Pseudosuchia †Dasygnathoides †Nundasuchus †Phytosauria? †Ornithosuchidae Aenigmaspina? Dynamosuchus Ornithosuchus Riojasuchus Venaticosuchus Suchia †Heteropelta? †Koilamasuchus? †Mandasuchus †Nundasuchus? †Ticinosuchus †Erpetosuchidae Archeopelta? Dyoplax? Erpetosuchus Pagosvenator Parringtonia Tarjadia †Aetosauriformes Acaenasuchus Euscolosuchus Revueltosaurus Aetosauria see Aetosauria †Gracilisuchidae Gracilisuchus Maehary? Turfanosuchus Yonghesuchus Paracrocodylomorpha see below↓

Paracrocodylomorpha
Paracrocodylomorpha †Mambawakale †Poposauroidea Lotosaurus Schultzsuchus? Qianosuchus Ctenosauriscidae Arizonasaurus Bromsgroveia Bystrowisuchus Ctenosauriscus Hypselorhachis Tsylmosuchus? Xilousuchus Poposauridae Dolichobrachium Poposaurus Shuvosauridae Effigia Shuvosaurus Sillosuchus Loricata †Apatosuchus †Arganasuchus †Batrachotomus †Dagasuchus †Decuriasuchus †Etjosuchus †Fasolasuchus †Heptasuchus †Heteropelta? †Incertovenator? †Luperosuchus †Mandasuchus? †Prestosuchus †Procerosuchus †Saurosuchus †Stagonosuchus †Youngosuchus †Rauisuchidae Arganasuchus? Energosuchus? Jushatyria? Polonosuchus Postosuchus Procerosuchus? Rauisuchus Scolotosuchus Scythosuchus? Teratosaurus Tikisuchus? Vivaron Vjushkovisaurus? Vytshegdosuchus? Crocodylomorpha see below↓

Crocodylomorpha
Crocodylomorpha †Carnufex †Dibothrosuchus †Dromicosuchus †Hesperosuchus †Heteropelta? †Junggarsuchus †Kayentasuchus †Parrishia †Phyllodontosuchus †Pseudhesperosuchus †Redondavenator †Sphenosuchus †Syntomiprosopus? †Trialestes †Saltoposuchidae Litargosuchus Saltoposuchus Terrestrisuchus †Hallopodidae Almadasuchus Hallopus Macelognathus †Thalattosuchia see Thalattosuchia Crocodyliformes †Entradasuchus †Eopneumatosuchus †Kemkemia †Microchampsa †Platyognathus †Stegomosuchus †Tagarosuchus †Protosuchidae Coloradisuchus Dianosuchus Edentosuchus Erythrochampsa Hemiprotosuchus Hoplosuchus Orthosuchus? Pedeticosaurus? Protosuchus †Notochampsidae Notochampsa Orthosuchus? †Gobiosuchidae Cassissuchus Gobiosuchus Lisboasaurus? Zaraasuchus Mesoeucrocodylia †Dianchungosaurus †Hsisosuchus †Induszalim †Lusitanisuchus †Neuquensuchus †Pachycheilosuchus? †Titanochampsa †Thalattosuchia? †Shartegosuchoidea Hadongsuchus Shantungosuchus Sichuanosuchus Zosuchus Shartegosuchidae Adzhosuchus Fruitachampsa Kyasuchus Nominosuchus Shartegosuchus Metasuchia †Ziphosuchia see Ziphosuchia includes notosuchians Neosuchia see Neosuchia includes crocodilians

• See also: Rauisuchia
• Prestosuchidae
• Bathyotica
• Sphenosuchia
• Protosuchia
• Mesosuchia
• Category