OMNH V823, Mussentuchit (Cretaceous of the United States)

Also known as UCM Loc. 83242, MNA 1072, UCM Loc. 83242

Where: Emery County, Utah (39.0° N, 111.0° W: paleocoordinates 40.3° N, 73.1° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: Mussentuchit Member (Cedar Mountain Formation), Early/Lower Cenomanian (99.6 - 93.5 Ma)

• A radiometric age of 98.37 ± 0.07 Ma was obtained by the OMNH from vol-canic ash within the Mussentuchit Member (Cifelli and others, 1997, 1999). Additional ages by Garrison and others (2007) ranging from 96.7 ± 0.5 to 98.2 ±0.6 Ma indicate that the Mussentuchit Member was deposited over an interval of 1.5 Ma during the early Cenomanian and supports a correlation with the siliceous marine Mowry Shale to the north, which is well-constrained from 40Ar/39Ar sanidine ages obtained from bentonite beds that bracket the Mowry in Wyoming; the basal Arrow Creek Bentonite is 98.5 ± 0.5 Ma and the capping Clay Spur Bentonite is 97.2 ± 0.7 Ma (Obradovich, 1993; Ogg and Hinnov, 2012; Sprinkel and others, 2012) near the base of the Upper Cretaceous. Tucker et al. 2020 also suggested a likely depositional age of ~96-94Ma for the Musseuntuchis member.

• bed-level stratigraphic resolution

Environment/lithology: terrestrial; lithology not reported

Size class: mesofossils

Collection methods: bulk, sieve,

Primary reference: J. G. Eaton and M. E. Nelson. 1991. Multituberculate mammals from the Lower Cretaceous Cedar Mountain Formation, San Rafael Swell, Utah. Contributions to Geology, University of Wyoming 29(1):1-12 [J. Alroy/J. Alroy/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 14395: authorized by John Alroy, entered by John Alroy on 21.09.1998, edited by Matthew Carrano and Roger Benson

Creative Commons license: CC BY (attribution)

Taxonomic list

• said to be Albian, and fm. dated at 101 Ma (no error: FT on zircon) by Kowallis et al. 1986; redated at 98.39 +/- 0.07 Ma (Ar/Ar on ash) by Cifelli et al. 1997
Mussentuchit Wash is about 8 mi WNW of Cedar Mountain in the far western part of Emery County
formation underlies the Dakota Fm. and technically speaking is in the Kaiparowits section
Mammalia
 Multituberculata -
Bryceomys intermedius3 Eaton and Cifelli 2001 multituberculate
MNA V5660
Paracimexomys "sp. A" Archibald 1982 multituberculate
MNA V5816; status unclear because second specimen apparently is not discussed by Eaton and Cifelli 2001
Paracimexomys robisoni n. sp. Eaton and Nelson 1991 multituberculate
UCM 54263-64, 54252, 54261; MNA V5655, 5678, 5708, 5817
"Paracimexomys bestia n. sp." = Cedaromys bestia Eaton and Nelson 1991 multituberculate
MNA V5656-58
Cedaromys parvus3 Eaton and Cifelli 2001 multituberculate
MNA V5665, UCM 54254
 Theriamorpha -
Sinbadelphys schmidti2 Cifelli 2004 metatherian
Reptilia
 Ornithischia -
Neoceratopsia indet.1 Sereno 1986 ceratopsian
 Squamata -
Squamata indet.4 squamates