Where: Dallas County, Texas (32.6° N, 97.0° W: paleocoordinates 33.0° N, 64.3° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Collignoniceras woollgari ammonoid zone, Arcadia Park Shale Formation, Middle Turonian (93.5 - 89.3 Ma)

• approximately 15 cm above Kamp Ranch Limestone; Collignoniceras woollgari Zone

•

•"...less than 20 cm above the Turonian Kamp Ranch limestone, which lies in the Collignoceras woollgari Zone. The ten metres overlying the Kamp Ranch have no reported ammonites and the Prionocyclus percarinatus Zone is not recorded... we consider that the postition of [the] type approximates the Collignoceras woollgari Zone... the absolute age is constrained by the underlying Vasoceras birchbyi Zone (93.40 +or- 0.63) and the overlying Prionocyclus percarinatus Zone (90.51 +or-0.45, each separated from the Collignoceras woollgari Zone by one missing zone. an estimate of ~92 Ma for the first appearance of these primitive mosasauroids is not unreasonable" (Jacobs et al. 2005, p. 262).

• bed-level stratigraphic resolution

Environment/lithology: marine; shale

Size class: macrofossils

Collected by M. Cohen in 1992

Primary reference: M. J. Polcyn and G. L. Bell. 2005. Russellosaurus coheni n. gen., n. sp., a 92 million-year-old mosasaur from Texas (USA), and the definition of the parafamily Russellosaurina. Netherlands Journal of Geosciences — Geologie en Mijnbouw 84(3):321-333 [M. Carrano/M. Carrano/F. Aspromonte]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 93824: authorized by Matthew Carrano, entered by Matthew Carrano on 03.02.2010

Creative Commons license: CC BY (attribution)