Big Bend National Park (west and east parts) (Cretaceous of the United States)

Also known as Mosasaur localities

Where: Brewster County, Texas (29.3° N, 103.6° W: paleocoordinates 31.3° N, 71.8° W)

• coordinate based on political unit

• local area-level geographic resolution

When: Ernst Member (Boquillas Formation), Late/Upper Turonian (93.5 - 89.3 Ma)

• Stratigraphy in text not defined with respect to geographic locality. Same geographical data will be used, and divisions based upon stratigraphic information.

•

•Approximately 85 m (280 ft) above the base of the unit

• formation-level stratigraphic resolution

Environment/lithology: marine; limestone

• Based on a section measured at Ernst Tinaja (type section of the Ernst Member) and using high resolution sequence stratigraphic methods, the Cenomanian–

•Turonian boundary was identified 283 m above the base of the Ernst Member. This occurs 65 cm above the top of a 30 cm bentonite couplet consisting of interbedded yellow, white, and maroon clays. Within this couplet is a thin bed of burrowed silty limestone with a diverse ammonite fauna representing perhaps as much as three Late Cenomanian ammonite zones. At 15 m above the Cenomanian–Turonian boundary is the highest hard limestone bed in this interval. It is 10–15 cm thick, with an undulatory base and iron-stained burrows on top. Its density and profuse borings suggest this bed represents a condensed zone or hardground. Immediately above this begins an 83 m-thick section strongly dominated by thick shale intervals with thin calcarenite beds and numerous, thin bentonite stringers.

Size class: macrofossils

Primary reference: G. L. Bell Jr., K. R. Barnes, and M. J. Polcyn. 2013. Late Cretaceous mosasauroids (Reptilia, Squamata) of the Big bend region in Texas, USA. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 103:571-581 [P. Mannion/J. Tennant/F. Aspromonte]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 151425: authorized by Philip Mannion, entered by Jonathan Tennant on 01.10.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Reptilia
 Squamata -
Mosasauroidea indet.
Mosasauroidea indet. squamates
TMM 43056-4, TMM-43352-6, TMM- 43352-12, TMM 43352-13
 Squamata - Mosasauridae
Tylosaurinae indet., Russellosaurina indet., Mosasaurinae indet.
Tylosaurinae indet. Wiliston 1895 mosasaur
TMM 43345-1; consists of most of an articulated skull, several cervical and trunk vertebrae, and ribs. A portion of the left side of the snout, including the premaxilla, was lost prior to discovery.
Russellosaurina indet. Bell 1997 mosasaur
TMM 43056-12, TMM 43342-1, TMM 43352-2, TMM 43352-16, TMM 43352-18, TMM 43359-4, TMM 43352-1, TMM 43352-14
Mosasaurinae indet. Gervais 1853 mosasaur
TMM 43056-3, TMM 43056-7, TMM 43352-11