Also known as SMU 76476

Where: Collin County, Texas (33.0° N, 96.8° W: paleocoordinates 34.5° N, 64.9° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: Atco Formation (Austin Group), Early/Lower Coniacian (89.3 - 85.8 Ma)

• "The palynological assemblage recovered from the matrix surrounding SMU 76476 contains two taxa (Tanyosphaeridium salpinx and Catastomocystis spinosa) that have last occurrences in the Turonian and two taxa (Dinogymnium acuminatum and Dinogymnium euclaense) that have first occurrences in the Coniacian. Pre-Coniacian reports (Londeix et al., 1996; Zippi, personal commun., 2009) of both D. acuminatum and D. euclaense initially suggested a likely Turonian age for SMU 76476, but the fissile, dark gray shales of the Turonian Eagle Ford Group north of Dallas are inconsistent with the matrix lithology. The limestone matrix surrounding SMU 76476 is consistent with the chalk deposits of the lower part of the Austin Group (Fig. 1), so T. salpinx and C. spinosa are interpreted as reworked from the underlying Eagle Ford Group. Given the presence of reworked Turonian taxa in the matrix, SMU 76476 must be derived from the basal Atco Formation within the Austin Group."

• bed-level stratigraphic resolution

Environment/lithology: marine; gray, muddy limestone

Size class: macrofossils

Collection methods: SMU: Shuler Museum of Paleontology, Southern Methodist University, Dallas

Primary reference: T. S. Myers. 2010. Earliest occurrence of the Pteranodontidae (Archosauria: Pterosauria) in North America: new material from the Austin Group of Texas. Journal of Paleontology 84:1071-1081 [R. Butler/R. Butler]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 100363: authorized by Richard Butler, entered by Richard Butler on 08.12.2010, edited by Graeme Lloyd

Creative Commons license: CC BY (attribution)