Bear Springs, Comanche National Grassland: Late/Upper Cenomanian, Colorado
collected by Bruce A. Schumacher 2006

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
unclassified
Vertebrata indet. (Lamarck 1801)
ca. 10,000 bone fragments
Chondrichthyes
Chondrichthyes indet. Huxley 1880
1 vertebra
Chondrichthyes - Hybodontiformes - Ptychodontidae
Ptychodus anonymus Williston 1900
35 teeth
Chondrichthyes - Rajiformes - Rhinobatidae
Rhinobatos incertus Cappetta 1973
4 teeth
Chondrichthyes - Lamniformes - Cretoxyrhinidae
Cretoxyrhina mantelli (Agassiz 1835)
4 teeth
Chondrichthyes - Lamniformes - Odontaspididae
Carcharias saskatchewanensis (Case et al. 1990)
recombined as Microcarcharias saskatchewanensis
24 teeth
Chondrichthyes - Lamniformes - Archaeolamnidae
Archaeolamna kopingensis (Davis 1890)
4 teeth
Chondrichthyes - Lamniformes - Aquilolamnidae
Cretomanta canadensis Case et al. 1990
1 tooth
Chondrichthyes - Lamniformes - Anacoracidae
Squalicorax curvatus (Williston 1900)
20 teeth
unclassified
Osteichthyes indet. (Huxley 1880)
18 vertebrae
Actinopteri - Amiiformes - Caturidae
Caturidae indet. Owen 1860
2 teeth
Actinopteri
Teleostei informal sp. A (Müller 1846)
8 teeth
Teleostei informal sp. B (Müller 1846)
17 teeth
Teleostei informal sp. C (Müller 1846)
11 teeth
Teleostei informal sp. D (Müller 1846)
2 teeth
Teleostei indet. (Müller 1846)
1 jaw bone
Actinopteri - Salmoniformes - Cimolichthyidae
Cimolichthys nepaholica (Cope 1872)
8 teeth
Actinopteri - Aulopiformes - Enchodontidae
Enchodus cf. gladiolus Cope 1872
3489 teeth, 1 jaw bone
Enchodus cf. shumardi Leidy 1856
12 teeth
Actinopteri - Aulopiformes - Ichthyotringidae
Apateodus sp. Woodward 1901
3 teeth
Actinopteri - Tselfatiiformes - Plethodidae
Plethodidae indet. Loomis 1900
7 teeth, 6 bones
Actinopteri - Crossognathiformes - Pachyrhizodontidae
Elopopsis sp.
22 teeth
cf. Pachyrhizodus sp. Agassiz 1850
1 tooth
Pachyrhizodus minimus Stewart 1899
1504 teeth
Actinopteri - Albuliformes - Albulidae
Albulidae indet. Bleeker 1859
1 tooth plate, 4 pieces
Actinopteri - Pachycormiformes - Pachycormidae
Protosphyraena sp. Leidy 1857
6 teeth
Actinopteri - Pycnodontiformes - Mesturidae
Micropycnodon kansasensis (Hibbard and Graffham 1941)
3 teeth
Actinopteri - Pycnodontiformes - Pycnodontidae
Palaeobalistum sp. Blainville 1818
5 teeth
Reptilia
Coniasaurus crassidens Owen 1850
18 teeth
Bivalvia - Myalinida - Inoceramidae
Inoceramidae indet. Giebel 1852
Bivalvia - Ostreida - Gryphaeidae
Exogyra aff. boveyensis
see common names

Geography
Country:United States State/province:Colorado
Coordinates: 37.7° North, 103.9° West (view map)
Paleocoordinates:37.4° North, 66.7° West
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period:Cretaceous Epoch:Late/Upper Cretaceous
Stage:Cenomanian 10 m.y. bin:Cretaceous 5
Key time interval:Late/Upper Cenomanian
Age range of interval:100.50000 - 93.90000 m.y. ago
Stratigraphy
Formation:Greenhorn Limestone Member:Hartland Shale
Stratigraphic resolution:bed
Stratigraphy comments: Lower one third of the Hartland Shale Member, roughly 4m above the contact with the underlying Lincoln Limestone Member. The calcarenite contains bivalve shells of taxonomically indeterminate inoceramids and the oyster Exogyra aff. E. boveyensis Bergquis , 1944. Exogyra aff. E. boveyensis was initially reported to occur in the middle Late Cenomanian based on the fossil record in Kansas (Hattin, 1975), but Kauffman et al. (1993) depicted the occurrence of this taxon (also referred to as “Exogyra n. sp. aff. E. boveyensis”) as restricted to their Calycoceras cantiaurinum ammonite zone, which is early Late Cenomanian in age. Regardless, the fossiliferous calcarenite bed examined in our study is interpreted to be early Late Cenomanian in age (ca. 94.6 Ma).
Lithology and environment
Primary lithology: lithified "limestone"
Includes fossils?Y
Lithology description: calcarenite
Environment:deep subtidal ramp
Geology comments: Periodic current events and/or depositional hiatuses during which skeletal debris was winnowed and concentrated. Whereas these brief depositional episodes might signal periods of temporary sea-level regression, they can be similarly explained as storm-winnowed debris from especially significant wave events, as evidenced by the abundance of clayey rip-up clasts.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils,mesofossils
Collection methods and comments
Collection methods:chemical,acetic,field collection
Reason for describing collection:general faunal/floral analysis
Collectors:Bruce A. Schumacher Collection dates:2006
Collection method comments: Repository: Sternberg Museum of Natural History, Fort Hays State University (FHSM)
Metadata
Database number:132505
Authorizer:P. Mannion Enterer:P. Mannion
Modifier:M. Clapham Research group:vertebrate
Created:2012-08-20 23:17:23 Last modified:2020-08-30 12:52:14
Access level:the public Released:2012-08-20 23:17:23
Creative Commons license:CC BY
Reference information

Primary reference:
42689. M. Nagrodski, K. Shimada, and B. A. Schumacher. 2012. Marine vertebrates from the Hartland Shale (Upper Cretaceous: Upper Cenomanian) in southeastern Colorado, USA. Cretaceous Research 37:76-88 [P. Mannion/P. Mannion/M. Clapham]