Chañares Formation

The Chañares Formation in La Rioja Provence, Argentina, dates to the Anisian stage of the early Middle Triassic.

Some localities are well known for their abundance of tetrapods. Theraspids include the kannemeyeriid Dinodontosaurus, and cynodonts such as Probainognathus and Massetognathus, the latter being the more abundant taxon.^[1] However, the most common group of tetrapods present from the formation are the archosaurs. Ornithodirans include Lewisuchus,^[2] Lagerpeton,^[3] Marasuchus,^[4] and Pseudolagosuchus.^[5] Other archosaurs include Gracilisuchus^[6] and Luperosuchus.^[7] Two proterochampsids are known from the formation, Chanaresuchus and Gualosuchus. They are very similar in appearance, differing only in size and cranial proportions.^[8]

Notes

1. ^ Romer, A. S. (1967). "The Chañares (Argentina) Triassic reptile fauna. III. Two new gomphodonts, Massetognathus pascuali and M. teruggii". Breviora 264: 1–25. 
2. ^ Romer, A. S. (1972). "The Chañares (Argentina) Triassic reptile fauna; XIV, Lewisuchus admixtus, gen. et sp. nov., a further thecodont from the Chañares beds". Breviora 390: 1–13. 
3. ^ Romer, A. S. (1971). "The Chañares (Argentina) Triassic reptile fauna. X. Two new but incompletely known long-limbed pseudosuchians". Breviora 378: 1–10. 
4. ^ Sereno, P. C.; Arcucci, A. B. (1994). "Dinosaurian precursors from the Middle Triassic of Argentina: Marasuchus lilloensis, gen. nov". Journal of Vertebrate Paleontology 14 (1): 53–73. doi:10.1080/02724634.1994.10011538. 
5. ^ Arcucci, A. B. (1987). "Un nuevo Lagosuchidae (Thecodontia-Pseudosuchia) de la fauna de Los Chañares (Edad Reptil Chañarense, Triasico Medio), La Rioja, Argentina". Ameghiniana 24 (1-2): 89–94. 
6. ^ Romer, A. S. (1972). "The Chañares (Argentina) Triassic reptile fauna. XIII. An early ornithosuchid pseudosuchian, Gracilisuchus stipanicicorum, gen. et sp. nov". Breviora 389: 1–24. 
7. ^ Romer, A. S. (1971). "The Chañares (Argentina) Triassic reptile fauna. VIII. A fragmentary skull of a large thecodont, Luperosuchus fractus". Breviora 373: 1–8. 
8. ^ Romer, A. S. (1971). "The Chañares (Argentina) Triassic reptile fauna. XI. Two new long-snouted thecodonts, Chanaresuchus and Gualosuchus". Breviora 379: 1–22.