Where: Utah (38.9° N, 110.1° W: paleocoordinates 37.3° N, 59.6° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Yellow Cat Member (Cedar Mountain Formation), Valanginian (139.8 - 132.9 Ma)

• A gravelly, calcareous sandstone often hosting a stromatolitic layer at its top that divides the Yellow Cat Member into an upper and lower sequence [34,35] has been informally designated the caprock in this area. The Hayden-Corbett site is above this regional marker bed, whereas both the Suarez and Crystal Geyser Quarries are below the caprock (Fig. 1). The upper Yellow Cat Member has been dated at about 124 Ma (early Aptian) based on detrital zircons.

•Date from "just above the capping sandstone above the Suarez site and below the Martharaptor site"

•

•The age of the base of the YCM is unknown and estimates range from Berrisian to early Aptian. Britt et al. 2007 suggested a maximum depositional age for the YCM of ~124Ma, but Sames et al. 2010 suggested on the basis of ostracod biostratigraphy the YCM may be as old as Late Berrisian. Hendrix et al. 2015 and Joeckel et al. 2019 supported this with U-Pb dates from detrital zircons, the latter study suggested that the upper YCM is Valanginian. At any rate, the age of the overlying Poison strip member was dated at its base to 119.4Ma, so the YCM is older than this.

Environment/lithology: crevasse splay; mudstone and sandstone

Size class: macrofossils

Collected by Martha Hayden

Collection methods: surface (float),

• UMNH collection (Natural History Museum of Utah, Salt Lake City, Utah).

•The bones of the holotype of M. greenriverensis were found disarticulated. However, there is no indication that more than one individual is present in the sample. All the skeletal material, including the surface ‘‘float’’ that drew attention to the skeleton, was found in an area of less than two square meters, and most of it is from an excavated mudstone block that is less than one square meter in lateral area and less than 0.2 m deep.

Primary reference: P. Senter, J. I. Kirkland, and D. D. DeBlieux. 2012. Martharaptor greenriverensis, a new theropod dinosaur from the Lower Cretaceous of Utah. PLoS ONE 7(8):e43911:1-12 [R. Benson/R. Benson/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 133038: authorized by Roger Benson, entered by Roger Benson on 31.08.2012

Creative Commons license: CC BY (attribution)