UCMP V84246, Tonahakaad Wash (Jurassic of the United States)

Where: Coconino County, Arizona (35.8° N, 111.1° W: paleocoordinates 15.8° N, 50.9° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Dinosaur Canyon Member (Moenave Formation), Hettangian (201.3 - 199.3 Ma)

• Collected 5 m below PaleoDB locality 46392

•Most of the Moenave Formation is the Dinosaur Canyon Member. In the Moenave type section, near Tuba City, Arizona, all of the Moenave section is Dinosaur Canyon Member, as it is throughout the Moenave outcrop belt along the Echo Cliffs and Ward's Terrace of northern Arizona. However, north of the Grand Canyon in Arizona and in southwestern Utah, the upper part of the Moenave Formation is lacustrine strata. These strata are the Whitmore Point Member.

•Lucas et al. (2011: Palaeo3 302: 194-205) proposed, on the basis of multiple lines of biostratigraphic evidence, that the Triassic–Jurassic boundary is placed within the middle part of the Whitmore Point Member of the Moenave Formation where this member is present, and high in the Dinosaur Canyon Member elsewhere. The "Whitmore Point assemblage" of vertebrate taxa, earliest Jurassic (Hettangian) in age. The underlying "Dinosaur Canyon assemblage", is latest Triassic (Rhaetian) in age.

• bed-level stratigraphic resolution

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Reposited in the UCMP

Primary reference: J. M. Clark and D. E. Fastovsky. 1986. Vertebrate biostratigraphy of the Glen Canyon Group in northern Arizona. The Beginning of the Age of the Dinosaurs: Faunal change across the Triassic-Jurassic boundary, N. C. Fraser and H.-D. Sues (eds.), Cambridge University Press 285-301 [R. Whatley/R. Whatley/R. Whatley]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 137295: authorized by Richard Butler, entered by Richard Butler on 14.12.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

Reptilia
 Loricata - Protosuchidae
Protosuchus richardsoni Brown 1933 crocodilian
UCMP 130860