Eutaw Formation Explained

Eutaw Formation
Type:Geological formation
Age:Upper Cretaceous
Period:Late Cretaceous
Prilithology:Glauconitic sandstone
Namedfor:Eutaw, Alabama
Region:Alabama, Georgia, Mississippi
Country:United States
Subunits:Tombigbee Sand Member, Ingersoll Shale
Underlies:Austin Group and Mooreville Chalk Formation
Overlies:Tuscaloosa Group
Thickness:40m (130feet) to 120m (390feet)

The Eutaw Formation is a geological formation in North America, within the U.S. states of Alabama, Georgia, and Mississippi. The strata date from the late Coniacian to the early Santonian stage of the Late Cretaceous.[1] It consists of the upper Tombigbee Sand Member and an unnamed lower member. Dinosaur, mosasaur, and pterosaur remains have been recovered from the Eutaw Formation.[2] [3]

Vertebrate paleofauna

Cartilaginous fish

Cartilaginous fish of the Eutaw Formation
TaxaSpeciesStateStratigraphic positionAbundanceNotesImages
ArchaeolamnaA. kopingensis[4] AlabamaA lamniform shark
BorodinopristisB. schwimmeriAlabamaA sclerorhynchid
BrachyrhizodusB. mcnultyiAlabamaMyliobatids
B. wichitaensis
CarchariasC. sp.AlabamaA lamniform shark
CantioscylliumC. globidensAlabamaCarpet sharks
C. decipiens (=C. meyeri or C. saginatus?)
ChiloscylliumC. greeniAlabamaA hemiscylliid
CretodusC. semiplicatusAlabamaA lamniform shark
CretalamnaC. appendiculataAlabamaOtodontids
C. serrata
CretoxyrhinaC. mantelliAlabamaA lamniform shark
EdaphodonE. sp.AlabamaA chimaera
Heterodontus?H. sp.AlabamaA heterodontiform
HybodusH. sp.AlabamaA hybodontid
IschyrhizaI. miraAlabamaA rajiform
Lissodus (=Lonchidion?)L. sp.AlabamaA hybodontid
ParanomotodonP. angustidensAlabamaA lamniform shark
PseudocoraxP. laevisAlabamaA lamniform shark
Pseudohypolophus (=Brachyrhizodus?)P. mcnultyiAlabamaA rajiform
PtychodusP. mortoniAlabamaPtychodontids
P. polygyrus
P. rugosus
PtychotrygonP. triangularis (=P. vermiculata and/or P. chattahoochiensis?)AlabamaA ptychotrygonid
Rajiformes indet.Alabama
ScapanorhynchusS. raphiodonAlabamaLamniform sharks
S. texanus
Sclerorhynchus?S. sp.AlabamaA rajiform
SqualicoraxS. falcatusAlabamaLamniform sharks
S. kaupi
S. pristodontus
SquatinaS. hasseiAlabamaA squatinid

Bony fish

Bony fish of the Eutaw Formation
TaxaSpeciesStateStratigraphic positionAbundanceNotesImages
AlbulaA. dunkleiAlabamaA bonefish
AnomoeodusA. phaseolusAlabamaA pycnodontid
AtractosteusA. sp.?AlabamaA gar
BananogmiusB. sp.AlabamaA plethodid
BelonostomusB. sp.AlabamaAn aspidorhynchiform
EnchodusE. petrosusAlabamaAn enchodontid
HadrodusH. priscusAlabamaA pycnodontid
LepisosteusL. sp.AlabamaA gar
MawsoniaM. sp.AlabamaA coelacanthiform fish
PhacodusP. puncatatusAlabamaA pycnodontiform
ProtosphyraenaP. sp.AlabamaA pachycormiform
StratodusS. apicalisAlabamaAn aulopiform
XiphactinusX. audaxAlabamaAn ichthyodectid

Turtles

Turtles of the Eutaw Formation
TaxaSpeciesStateStratigraphic positionAbundanceNotesImages
ChedighaiiC. barberiAlabamaA bothremydid
ProtostegaP. gigasAlabamaA protostegid
ThinochelysT. sp.Alabama
ToxochelysT. sp.Alabama
Trionychidae indet.Alabama

Plesiosaurs

Plesiosaurs of the Eutaw Formation
TaxaSpeciesStateStratigraphic positionAbundanceNotesImages
DiscosaurusD. vetustusAlabamaAn elasmosaurid
Elasmosauridae indet.Alabama

Mosasaurs

Mosasaurs of the Eutaw Formation
TaxaSpeciesStateStratigraphic positionAbundanceNotesImages
ClidastesClidastes sp.AlabamaA mosasaurine
EonatatorE. sternbergii[5] AlabamaA halisaurine
  1. E. sternbergii was formerly classified as Halisaurus sternbergii
GlobidensG. alabamaensisAlabamaA mosasaurine
PlatecarpusP. tympaniticusAlabamaA plioplatecarpine
PlioplatecarpusP. sp.AlabamaA plioplatecarpine
SelmasaurusS. russelliAlabamaA plioplatecarpine
TylosaurusT. nepaeolicusAlabamaTylosaurines
T. proriger

Crocodylians

Crocodylians of the Eutaw Formation
GenusSpeciesStateStratigraphic positionAbundanceNotesImages
BorealosuchusB. sp.AlabamaAn eusuchian
DeinosuchusD. rugosus?AlabamaAn alligatoroid
LeidyosuchusL. sp.AlabamaAn alligatoroid

Ornithodires

Dinosaur feathers have been found in the Ingersoll Shale of Georgia, which is a subunit of the Eutaw Formation.[3] Indeterminate hadrosaurid remains have been found in Mississippi.[6] Ornithomimosaurs of medium-size and large-size have also been unearthed in Mississippi.[7]

Ornithodires of the Eutaw Formation
GenusSpeciesStateStratigraphic positionAbundanceNotesImages
LophorhothonL. atopusAlabamaA hadrosauromorph dinosaur
PteranodonIndeterminateGeorgiaA pteranodontid pterosaur

See also

Notes and References

  1. Web site: Liu . Kaiyu . Facies Changes of the Eutaw Formation (Coniacian-Santonian), Onshore to Offshore, Northeastern Gulf of Mexico Area. 2009-02-10. Department of Geological Sciences. University of Alabama.
  2. Kiernan . Caitlin R. . 2002 . Stratigraphic distribution and habitat segregation of mosasaurs in the Upper Cretaceous of western and central Alabama, with an historical review of Alabama mosasaur discoveries . Journal of Vertebrate Paleontology . 22 . 1 . 91–103 . 10.1671/0272-4634(2002)022[0091:SDAHSO]2.0.CO;2 . 130280406 .
  3. Encyclopedia: Coastal Plain Geologic Province. 2009-02-10. 2007-08-30. The New Georgia Encyclopedia. Georgia Humanities Council and the University of Georgia Press.
  4. Kejiri, T.. Ebersole, J.A.. Blewitt, H.L.. Ebersole, S.M.. 2013. An Overview of Late Cretaceous Vertebrates from Alabama. Bulletin of the Alabama Museum of Natural History. 31. 1. 46–71.
  5. 2002 . A new species of Halisaurus from the Late Cretaceous phosphates of Morocco, and the phylogenetical relationships of the Halisaurinae (Squamata: Mosasauridae) . Zoological Journal of the Linnean Society. 143 . 3 . 447–472 . Bardet N, Suberbiola P, Iarochene M, Bouyahyaoui F, Bouya B, Amaghzaz M . 10.1111/j.1096-3642.2005.00152.x . free .
  6. Kaye . John M. . Russell . Dale A. . The Oldest Record of Hadrosaurian Dinosaurs in North America . Journal of Paleontology . January 1973 . 47 . 1 . 91–93 . 1302869 .
  7. Chinzorig . Tsogtbaatar . Cullen . Thomas . Phillips . George . Rolke . Richard . Zanno . Lindsay E. . 2022-03-25 . Large-bodied ornithomimosaurs inhabited Appalachia during the Late Cretaceous of North America . en . 2022.03.25.485782 . 10.1101/2022.03.25.485782. 247749395 .