La Boca Formation

The La Boca Formation is a geological formation in Tamaulipas state, northeast Mexico. It was trougth to date back to the Early Jurassic, concretely the Pliensbachian stage epoch.[3][4] Altrougth, the latest studies had proven that the local Vulcanism, related to the aperture of the Atlantic Ocean and the several Rift Events, that continue until the Bajocian where developed until the Latest Pliensbachian, with tha fossil taxa deposited on the rocks above.[5] Due to successions of Aalenian depositional sistems on the upper layers of the Huizachal Canyon, has been delimited the formation to the Toarcian stage, being the regional equivalent of the Moroccan Azilal Formation.[2][1]

La Boca Formation
Stratigraphic range: Upper Pliensbachian-Lower Bajocian, 183–165 Ma
[1][2]
TypeGeological formation
Unit ofHuizachal Group
Sub-units
  • Upper Part with Epiclastic Sedimentation
  • Lower Part with Pyroclastic sedimentation
UnderliesLa Joya Formation
OverliesHuizachal Formation
Thickness<10 m
Lithology
PrimaryRed sandstones, mudstones, and siltstones
OtherPyroclastic volcanic rocks
Location
RegionTamaulipas
Country Mexico

Fossil record

Unclassified Diapsida

Genus Species Location Stratigraphic position Abundance Notes Images

Tamaulipasaurus[6]

T. morenoi

Dinosaur National Monument South, Huizachal Canyon

Lower Part

Skull and several fragmentary remains

A strange burrowing Diapsid: "Burrowing diapsid representing a heretofore unknown clade"[6]

Synapsida

Genus Species Location Stratigraphic position Abundance Notes Images

Bocaconodon[7]

B. tamaulipensis[7]

Jim's Joy, Huizachal Canyon

Lower Part

Teeth

A basal Mammaliaform[7]

Bocatherium[8]

B. mexicanum[8]

Huizachal Canyon

Lower Part

IGM 3492, Skull

A Tritylodontid[8]

Huasteconodon[7]

H. wiblei[7]

Huizachal Canyon

Lower Part

Teeth

A Gobiconodont[7]

Victoriaconodon[7]

V. inaequalis[7]

Rene's Roost, Huizachal Canyon

Lower Part

Teeth

A Triconodontid[7]

Unnamed Mammaliaforms (IGM 6622,IGM 6855, and IGM 6856)[7]

Indeterminate

  • Cementario, Huizachal Canyon
  • Casa de Fidencio, Huizachal Canyon

Lower Part

IGM 6855, partial right dentary; IGM 6856, left dentary; IGM 6622, partial right dentary

Sphenodontia

Genus Species Location Stratigraphic position Abundance Notes Images

Cynosphenodon[9]

C. huizachalensis

Huizachal Canyon

Lower Part

Jaws & teeth of various specimens

A Sphenodontidae Rhynchocephalian.[10]

Sphenovipera[11]

S. jimmysjoyi[11]

Jim's Joy, Huizachal Canyon

Lower Part

IGM 6076, right lower jaw

A venomous Sphenodont[11]

Zapatadon[12]

Z. ejidoensis

Tierra Buena, W Huizachal Canyon

Lower Part

Jaws

A dwarf Sphenodont


Pterosauria

Genus Species Location Stratigraphic position Abundance Notes Images

"Dimorphodon"[13]

"D." weintraubi

Huizachal Canyon

Lower Part

Fragmentary skeleton of a large rhamphorhynchoid that includes a remarkably preserved pes.

A Pterosaur of uncertain phylogenetic placement, being originally proposed as a member of the genus Dimorphodon, altrougth, has some great differences with the original holotype, and Dimorphodon is a lower Liassic Genus. Most recent analises place it on different positions on Novialoidea.[14]


Crocodrylomorpha

Genus Species Location Stratigraphic position Abundance Notes Images

Unnamed Crocodyliforms[8][15]

Indeterminate

Huizachal Canyon

Lower Part

Skull fragment

Non compared

Metasuchia[8]

? Metasuchia indeterminate

Huizachal Canyon

Lower Part

IGM 3498 & additional specimens. Partial skulls and postcranial skeletons

Non compared


Dinosauria

Genus Species Location Stratigraphic position Abundance Notes Images

"Syntarsus"[16]

"Syntarsus" mexicanum [17]

Casa de Fidencio, Huizachal Canyon

Lower Part

(IGM 6624) partial twelfth dorsal vertebra, partial thirteenth dorsal vertebra, partial synsacrum, incomplete fused pelvis

An indeterminate Coelophysoidean.

Ceratosauria[16]

Ceratosauria Indeterminate

Casa de Fidencio, Huizachal Canyon

Lower Part

IGM 6625, craneal fragmentary elements

A possible basal ceratosaur related with the African Berberosaurus.

Neotheropoda[16]

Neotheropoda Indeterminate

Huizachal Canyon

Lower Part

Isolated teeth

Several morphotypes, maybe related with Coelophysoidea, Dilophosauridae or Tetanurae.[16]

Heterodontosauridae[18]

cf. Heterodontosaurus sp.

Huizachal Canyon

Lower Part

Teeth

An Ornithischian of the family Heterodontosauridae.

?Sauropodomorpha[4][16]

?Sauropodomorpha indeterminate

Rene's Roost, Huizachal Canyon

Lower Part

Large bone fragments

A possible Basal Sauropodomorph.

See also

References

  1. Rubio-Cisneros, I. I., & Lawton, T. F. (2011). Detrital zircon U-Pb ages of sandstones in continental red beds at Valle de Huizachal, Tamaulipas, NE Mexico: Record of Early-Middle Jurassic arc volcanism and transition to crustal extension. Geosphere, 7(1), 159-170.
  2. Martini, M., & Ortega-Gutiérrez, F. (2018). Tectono-stratigraphic evolution of eastern Mexico during the break-up of Pangea: A review. Earth-Science Reviews, 183, 38-55.
  3. Mesozoic Sedimentary and Tectonic History of North-central Mexico, Issue 340, pg 206; edited by Claudio Bartolini, James Lee Wilson, Timothy Frost Lawton.
  4. Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 537–538. ISBN 0-520-24209-2.
  5. Boschman, L., Van Hinsbergen, D. J., Langereis, C. G., Molina-Garza, R. S., & Kimbrough, D. L. (2017, December). Paleomagnetic Constraints on the Tectonic History of the Mesozoic Ophiolite and Arc Terranes of Western Mexico. In AGU Fall Meeting Abstracts.
  6. Clark, J. M. (1994). A new burrowing diapsid from the Jurassic La Boca Formation of Tamaulipas, Mexico. Journal of Vertebrate Paleontology, 14(2), 180-195.
  7. Montellano, M., Hopson, J. A., & Clark, J. M. (2008). Late Early Jurassic mammaliaforms from Huizachal Canyon, Tamaulipas, México. Journal of Vertebrate Paleontology, 28(4), 1130-1143.
  8. Fraser, Nicholas; Sues, Hans-Dieter, eds. (1994). In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods. Cambridge University Press. ISBN 0-521-45242-2.
  9. Reynoso, V. H. (1996). A Middle Jurassic Sphenodon-like sphenodontian (Diapsida: Lepidosauria) from Huizachal Canyon, Tamaulipas, Mexico. Journal of Vertebrate Paleontology, 16(2), 210-221.
  10. Reynoso, V. H. (2003). Growth patterns and ontogenetic variation of the teeth and jaws of the Middle Jurassic sphenodontian Cynosphenodon huizachalensis (Reptilia: Rhynchocephalia). Canadian Journal of Earth Sciences, 40(4), 609-619.
  11. Reynoso, V.H. 2005. Possible evidence of a venom apparatus in a Middle Jurassic sphenodontian from the Huizachal red beds of Tamaulipas, Mexico. Journal of Vertebrate Paleontology 25: 646–653. doi:10.1671/0272-4634(2005)025[0646:PEOAVA]2.0.CO;2
  12. V.-H. Reynoso and J. M. Clark. 1998. A dwarf sphenodontian from the Jurassic La Boca Formation of Tamaulipas, Mexico. Journal of Vertebrate Paleontology 18:333-339
  13. Clark, J. M., Hopson, J. A., Fastovsky, D. E., & Montellano, M. (1998). Foot posture in a primitive pterosaur. Nature, 391(6670), 886-889.
  14. Britt, B. B., Dalla Vecchia, F. M., Chure, D. J., Engelmann, G. F., Whiting, M. F., & Scheetz, R. D. (2018). Caelestiventus hanseni gen. et sp. nov. extends the desert-dwelling pterosaur record back 65 million years. Nature ecology & evolution, 2(9), 1386-1392.
  15. V.-H. Reynoso. 2006. Research on fossil amphibians and reptiles in Mexico, from 1869 to early 2004 (including marine forms but excluding pterosaurs, dinosaurs, and obviously, birds). In F. J. Vega, T. G. Nyborg, M. Del Carmen Perrilliat, M. Montellano-Ballesteros, S. R. S. Cevallos-Ferriz, S. A. Quiroz-Barroso (eds.), Studies on Mexican Paleontology 24:209-231
  16. R. C. Munter and J. M. Clark. 2006. Theropod dinosaurs from the Early Jurassic of Huizachal Canyon, Mexico. In M. T. Carrano, T. J. Gaudin, R. W. Blob, J. R. Wible (eds.), Amniote paleobiology: perspectives on the evolution of mammals, birds, and reptiles. University of Chicago Press, Chicago 53-7
  17. González, De Stefano and Hernandez, 2002. [unknown title] in González and Stéfano (eds.). Fósiles de México- Coahuila: Una ventana a través del tiempo. Gobierno del Estado de Coahuila. 214-215.
  18. Clark, James; Montellano, Marisol; Hopson, James A.; Hernandez, Rene; Fastovsky, David A. (1994). "An Early or Middle Jurassic tetrapod assemblage from the La Boca Formation, northeastern Mexico". In Fraser, N.C.; Sues H.-D. (eds.). In The Shadow of the Dinosaurs: Early Mesozoic Tetrapods. Cambridge: Cambridge University Press. pp. 295–302. ISBN 0-521-45899-4.


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