AGr-4: Early/Lower Campanian - Middle Campanian, Alabama
collected by S. L. Olson 1992
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Reptilia
- Testudines
- Ctenochelyidae
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Ctenochelys acris
Zangerl 1953
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Gentry 2017 | 1 specimen | ||||||||
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Reptilia
- Avisauridae
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Halimornis thompsoni n. gen., n. sp.
Chiappe et al. 2002
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Reptilia
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Ichthyornis dispar
Marsh 1872
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Benito et al. 2022 | |||||||||
| MSC 5895, 7841, 7844 | ||||||||||
| see common names | ||||||||||
Geography
| Country: | United States | State/province: | Alabama | County: | Greene |
| Coordinates: | 32.9° North, 88.2° West (view map) | ||||
| Paleocoordinates: | 35.7° North, 60.2° West | ||||
| Basis of coordinate: | estimated from map | ||||
| Geographic resolution: | small collection |
Time
| Period: | Cretaceous | Epoch: | Late/Upper Cretaceous |
| Stage: | Campanian | 10 m.y. bin: | Cretaceous 7 |
| Key time interval: | Early/Lower Campanian - Middle Campanian | ||
| Age range of interval: | 83.60000 - 72.10000 m.y. ago |
Stratigraphy
| Geological group: | Selma | Formation: | Mooreville Chalk | ||
| Stratigraphic resolution: | formation | ||||
| Stratigraphy comments: "lower member of the Mooreville Chalk Formation [which] ranges from latest Santonian to middle Campanian in age... AGr-4... lies in approximately the middle of the Mooreville Chalk Formation... Thus [it is] late-early to early-middle Campanian in age" Chiappe et al. 2002.
Per Gentry 2016 "Isotopic analysis (Liu 2009) and nanofossils (Raymond et al. 1988) from the Mooreville Chalk of Greene County indicate a Campanian age for these deposits of between 82 and 83.5 Ma." | |||||
Lithology and environment
| Primary lithology: | concretionary,pyritic "carbonate" |
| Lithology description: vertebrate fossils are from dark "dysoxic layers" that "contain abundant pyrite concretions" | |
| Environment: | deep subtidal shelf |
| Geology comments: "a near-shore depositional environment... [with] fairly clean, shallow waters of normal marine salinity within a warm climatic regime... AGr-4 is estimated to have been about 50 km offshore" | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
| Articulated whole bodies: | some |
Collection methods and comments
| Collection methods: | selective quarrying,surface (float) | ||
| Reason for describing collection: | general faunal/floral analysis | ||
| Collectors: | S. L. Olson | Collection dates: | 1992 |
| Collection method comments: many "elements were found as a fan-shapeed scatter on a slightly sloping surface" and "a few" others were found during "subsequent excavation" | |||
Metadata
| Database number: | 80890 | ||
| Authorizer: | M. Uhen, P. Mannion, P. Holroyd | Enterer: | M. Uhen, P. Holroyd, P. Mannion |
| Modifier: | P. Holroyd | Research group: | vertebrate |
| Created: | 2008-05-19 14:56:55 | Last modified: | 2016-09-24 02:07:31 |
| Access level: | the public | Released: | 2008-05-19 14:56:55 |
| Creative Commons license: | CC BY |
Reference information
Primary reference:
| 27220. | L. M. Chiappe, J. P. Lamb, and P. G. P. Ericson. 2002. New enantiornithine bird from the marine upper Cretaceous of Alabama. Journal of Vertebrate Paleontology 22(1):170-174 [M. Uhen/M. Uhen] |
Secondary references:
| 85525 | J. Benito, A. Chen, L. E. Wilson, B.-A. S. Bhullar, D. Burnham and D. J. Field. 2022. Forty new specimens of Ichthyornis provide unprecedented insight into the postcranial morphology of crownward stem group birds. PeerJ 10:e13919 [P. Mannion/P. Mannion] | |
| 60410 | A. D. Gentry. 2017. New material of the Late Cretaceous marine turtle Ctenochelys acris Zangerl, 1953 and a phylogenetic reassessment of the ‘toxochelyid’-grade taxa. Journal of Systematic Palaeontology 15(8):675-696 [P. Holroyd/P. Holroyd/P. Mannion] |