Huizachal Canyon (Jurassic of Mexico)

Where: Tamaulipas, Mexico (26.6° N, 99.5° W: paleocoordinates 26.6° N, 99.5° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: La Boca Formation, Pliensbachian (190.8 - 182.7 Ma)

• lower part of the La Boca Formation; originally dated as Middle Jurassic, but U-Pb isotopic data from zircon in a volcaniclastic rock from the lowest part of the formation yields an age of 189 plus/minus 0.2 Ma. The fossil-bearing sedimentary rocks are above this unit and conformable with it (see Montellano et al. 2008).

• member-level stratigraphic resolution

Environment/lithology: "floodplain"; lithified, volcaniclastic siltstone

• "deposited as a subaerial, waterlain debris flow"

Size classes: macrofossils, mesofossils

Collected by J. Clark in 1982-

Collection methods: surface (float), surface (in situ), mechanical,

• IGM: Instituto de Geologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico

Primary reference: J. M. Clark and J. A. Hopson. 1985. Distinctive mammal-like reptile from Mexico and its bearing on the phylogeny of the Tritylodontidae. Nature 315(6018):398-400 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 28212: authorized by Matthew Carrano, entered by Matthew Carrano on 30.01.2003, edited by Richard Butler and Jonathan Tennant

Creative Commons license: CC BY (attribution)

Taxonomic list

 Saurischia -
Theropoda indet.2 Marsh 1881 theropod
Isolated teeth
 Pterosauria - Dimorphodontidae
Dimorphodon weintraubi n. sp.1 Clark et al. 1998 pterosaur
"new species"
 Loricata -
Crocodylomorpha indet.5 Hay 1930 crocodilian
Skull fragment
? Metasuchia indet.2 crocodilian
"new species"; IGM 3498 & additional specimens. Partial skulls and postcranial skeletons
 Rhynchocephalia - Sphenodontidae
Cynosphenodon huizachalensis n. gen. n. sp.4 Reynoso 1996 rhynchocephalian
IGM 6652, dentary. IGM 6653-6660, upper and lower jaws, and 16 incomplete lower jaws
 Therapsida - Tritylodontidae
Bocatherium mexicanum n. sp. Clark and Hopson 1985 therapsid
IGM 3492 (holotype), skull
 Eutriconodonta - Gobiconodontidae
Huasteconodon wiblei n. gen. n. sp.3
Huasteconodon wiblei n. gen. n. sp.3 Montellano et al. 2008 mammal
"taxon C"