Aguja Formation

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Aguja Formation
Stratigraphic range: Campanian-Maastrichtian, 80.5–72Ma
Type Geological formation
Unit of Tornillo Group
Sub-units
  • Upper Shale Member
  • Terlingua Creek Sandstone Member
  • McKinney Springs Marine Tongue
  • Rattlesnake Mt. Sandstone Member
  • Lower Shale Member
  • Basal Sandstone Member
Underlies Javelina Formation
Overlies Pen Formation
Location
Region  Texas  Chihuahua
Country  USA  Mexico

The Aguja Formation is a geological formation in North America, exposed in Texas, whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.[1]

Age[edit]

The ages of the Aguja Formation and its primary fossil-bearing unit, the Upper Shale, are not well understood. Two radiometric dates have been taken from different sections of the upper shale, yielding ages of 72.6 Ma +/- 1.5 Ma old, and 76.9 Ma +/- 1.2 Ma old, respectively.[2] The contact with the overlying Javelina Formation has been estimated at about 70 Ma ago[3] but also as recently as 68.5 million years ago.[4] The base of the entire Aguja Formation has been estimated at about 80.5 million years old.[5]

Invertebrate paleofauna[edit]

Ammonites[edit]

Ammonites of the Aguja Formation
Genus Species Location Member Abundance Notes Images

Baculites

B. mclearni

  • Rattlesnake Mountain Sandstone

Hoplitoplacenticeras

H. plasticum

  • Rattlesnake Mountain Sandstone

Pachydiscus

P. paulsoni

  • Rattlesnake Mountain Sandstone

Vertebrate paleofauna[edit]

Crurotarsans[edit]

Crurotarsans of the Aguja Formation
Genus Species Location Member Material Notes Images

Deinosuchus[6]

D. riograndensis[6]

Deinosuchus skull reconstruction.

Phobosuchus[6]

P. riograndensis[6]

Reclassified as a Deinosuchus species.

Ornithischians[edit]

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Ornithischians of the Aguja Formation
Genus Species Location Member Material Notes Images

Agujaceratops[7]

A. mariscalensis[7]

  • Low Upper Shale[2]

The type species, A. mariscalensis, was formerly considered a species of Chasmosaurus.[7]

Angulomastacator[8]

A. daviesi[8]

Chasmosaurus[9]

C. mariscalensis[10]

"[Twelve] disarticulated skull (sic), postcrania, juvenile."[11]

Considered by paleontologists Lucas, Sullivan, and Hunt to be distinct enough from the Chasmosaurus type species, C. belli to warrant being split off to a new genus, Agujaceratops.[7]

Indeterminate[12]

Edmontonia[10]

E. rugosidens[13]

Euoplocephalus[10]

Unnamed species[10]

Unnamed genus and species[14]

Formerly referred to Kritosaurus and Gryposaurus, appears to be an unnamed species related to Secernosaurus.[15]

Kritosaurus[9]

K. cf. navajovius[16]

Indeterminate[9]

Panoplosaurus[10]

Unnamed species[10]

Stegoceras[10]

Indeterminate[10]

Texacephale[18]

T. langstoni[18]

  • Low Upper Shale[2]

Saurischians[edit]

Indeterminate ornithomimid remains are known from the Upper Aguja Formation.[5] Indeterminate tyrannosaurid fossils are known from the Upper Aguja Formation of Texas and Mexico.[19]

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Saurischians of the Aguja Formation
Genus Species Location Member Material Notes Images

cf. Daspletosaurus[20]

Indeterminate[21]

cf. Dromaeosaurus[23]

Indeterminate[23]

Leptorhynchos

L. gaddisi

A caenagnathid.

Ricardoestesia[25]

R. cf. gilmorei[26]

R. isosceles[25]

Saurornitholestes[10]

S. cf. langstoni[27]

cf. Troodon[28]

Indeterminate[28]

Turtles[edit]

Testudines of the Aguja Formation
Genus Species Location Member Material Notes

Terlinguachelys[6]

T. fischbecki[6]

  • Texas
  • Rattlesnake Mountain Sandstone[6]

See also[edit]

Footnotes[edit]

  1. ^ Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. ISBN 0-520-24209-2.
  2. ^ a b c Longrich, N. R.; Sankey, J.; Tanke, D. (2010). "Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA". Cretaceous Research 31 (2): 274. doi:10.1016/j.cretres.2009.12.002.  edit
  3. ^ Woodward, H. N. (2005). Bone histology of the sauropod dinosaur Alamosaurus sanjuanensis from the Javelina Formation, Big Bend National Park, Texas.
  4. ^ Sankey, J. (2010). Faunal composition and significance of high–diversity, mixed bonebeds containing Agujaceratops mariscalensis and other dinosaurs, Aguja Formation (Upper Cretaceous), Big Bend, Texas. In New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium (pp. 520-537).
  5. ^ a b Sullivan, R.M., and Lucas, S.G. 2006. "The Kirtlandian land-vertebrate "age" – faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America." New Mexico Museum of Natural History and Science, Bulletin 35:7-29.
  6. ^ a b c d e f g h i "Aguja Formation (Upper Shale Member), Big Bend Region, Texas," in Sullivan and Lucas (2006). Page 16.
  7. ^ a b c d e "Abstract," Lucas, Sullivan, and Hunt. (2006).
  8. ^ a b c Wagner and Lehman (2009).
  9. ^ a b c "Dinosaur distribution (Texas and Chihuahua)." Weishampel, et al. (2004). Page 582 and 588.
  10. ^ a b c d e f g h i j k l m n o p q r s "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.
  11. ^ "Table 23.1," in Weishampel, et al. (2004). Page 496.
  12. ^ a b Listed as ?Chasmosaurus sp. in "Dinosaur distribution (Late Cretaceous; North America; Chihuahua)." Weishampel, et al. (2004). Page 588.
  13. ^ Listed as Edmontonia cf. rugosidens in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.
  14. ^ Listed as ?Gryposaurus sp. in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.
  15. ^ Prieto-Márquez, A. (2013). "Skeletal morphology of Kritosaurus navajovius (Dinosauria:Hadrosauridae) from the Late Cretaceous of the North American south-west, with an evaluation of the phylogenetic systematics and biogeography of Kritosaurini." Journal of Systematic Palaeontology, (advance online publication) doi:10.1080/14772019.2013.770417
  16. ^ Listed as Kritosaurus cf. navajovius in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.
  17. ^ "Dinosaur distribution (Late Cretaceous; North America; Chihuahua)." Weishampel, et al. (2004). Page 588.
  18. ^ a b c "Abstract," Longrich, Sankey, and Tanke (2010).
  19. ^ Mortimer, M (2004). "Tyrannosauroidea". The Theropod Database. Retrieved 2007-08-21. 
  20. ^ Mortimer, M (2004). "Tyrannosauroidea". The Theropod Database. Retrieved 2007-08-21. 
  21. ^ Mortimer, M (2004). "Tyrannosauroidea". The Theropod Database. Retrieved 2007-08-21. 
  22. ^ Mortimer, M (2004). "Tyrannosauroidea". The Theropod Database. Retrieved 2007-08-21. 
  23. ^ a b Listed as cf. Dromaeosaurus sp. in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.
  24. ^ Longrich, N. R.; Barnes, K.; Clark, S.; Millar, L. (2013). "Caenagnathidae from the Upper Campanian Aguja Formation of West Texas, and a Revision of the Caenagnathinae". Bulletin of the Peabody Museum of Natural History 54: 23. doi:10.3374/014.054.0102. edit
  25. ^ a b c d "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 581.
  26. ^ Listed as R. cf. gilmorei in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 581.
  27. ^ Listed as Saurornitholestes cf. langstoni in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.
  28. ^ a b Listed as cf. Troodon sp. in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.

References[edit]