St. Marys Formation

St. Marys Formation
Stratigraphic range:
TypeFormation
Unit ofChesapeake Group
UnderliesEastover Formation
OverliesChoptank Formation
Location
RegionMaryland, Virginia
CountryUnited States

The St. Marys Formation is a geologic formation in Maryland and Virginia, United States. It preserves fossils dating back to the Tortonian stage of the Late Miocene epoch of the Neogene period (11 to 8 million years ago).[1] It is the youngest Miocene formation present in the Calvert Cliffs and is part of the Chesapeake Group.

Vertebrate paleofauna

A diverse vertebrate paleofauna is known from the St. Marys Formation:

Cartilaginous fish
Genus Species Notes Tooth example Ref.
Notorynchus N. primigenius This species is possibly synonymous with the broadnose sevengill shark. [2]
Hexanchus H. gigas A species of cow shark. This species is extremely rare in this formation. [2]
Squalus Commonly known as the spurdog. [2]
Squatina Commonly known as the angel shark. [2]
Rhincodon R. typus Commonly known as the whale shark. This species is extremely rare in this formation. [2]
Carcharodon C. hastalis Putative ancestor to the extant great white shark [2]
Carcharomodus C. escheri Commonly known as Escher's mako. It is also known as Carcharodon subserratus and is sometimes placed in Isurus. It is extremely rare in this formation. [2]
Otodus O. megalodon This is the largest shark known to have existed. [2]
Alopias A. latidens This species may be synonymous with the extant common thresher shark. [2]
Mustelus Commonly known as smooth-hounds [2]
Hemipristis H. serra Commonly known as the snaggletooth shark. It is related to the extant snaggletooth shark. [2]
Carcharhinus C. falciformus Commonly known as the silky shark. [2]
C. leucas Commonly known as the bull shark [2]
C. perezii Commonly known as the Caribbean reef shark [2]
C. priscus An extinct requiem shark [2]
C. plumbeus Commonly known as the sandbar shark [2]
Negaprion N. brevrostris Commonly known as the lemon shark [2]
Rhizoprionodon Commonly known as the sharpnose shark [2]
Pteromylaeus Commonly known as the bull ray [2]
Aetobatus Commonly known as the eagle ray [2]
Bony fish
Genus Notes Image Ref.
Acipenseridae gen. indet. [2]
Lepisosteus [2]
Amia cf. A. calva [2]
Alosa [2]
Ictalurus [2]
Merluccius [2]
Belone B. countermani [2][3]
Prionotus [2]
Agonidae gen. indet. [2]
"Paralbula" "P." dorisiae [2]
Lagodon [2]
Stenotomus [2]
Pogonias [2]
Sciaenops [2]
Tautoga [2]
Astroscopus A. countermani [4][2]
Sphyraena [2]
Istiophoridae gen. indet. [2]
Reptiles
Genus Species Notes Image Ref.
Thecachampsa T. antiquus A Tomistominae [2]
Sea mammals
Type Genus Species Notes Image Ref.
Sirenians (sea cows) Metaxytherium M. floridanum [2]
Cetaceans (whales, dolphins and porpoises) Aulophyseter A. mediatlanticus A sperm whale [5]
Lophocetus L. calvertensis [6]
Messapicetus [7]
Stenasodelphis S. russellae [8]
Terrestrial mammals
Name Notes Images Ref.
Procamelus cf. P. minor [9]
Desmathyus [9]
Tapirus [9]
Neohipparion lenticulare [9]
Equidae indet. Larger than Parahippus [9]
Rhinoceratidae [9]
Cormohipparion [9]

See also

References

  1. ^ Carnevale, Giorgio; Godfrey, Stephen James (2018). "Miocene bony fishes from the Calvert, Choptank, St. Marys and Eastover Formations, Chesapeake Group, Maryland and Virginia". Smithsonian Contributions to Paleobiology (100).
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an Godfrey, Stephen J., ed. (2018-09-25). "The Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland, USA". Smithsonian Contributions to Paleobiology (100): 2–274. doi:10.5479/si.1943-6688.100. ISSN 1943-6688.
  3. ^ de Sant'Anna, V. B., Collette, B. B., & Godfrey, S. J. (2013). † Belone countermani, a new Miocene needlefish (Belonidae) from the St. Marys Formation of Calvert Cliffs, Maryland. Proceedings of the Biological Society of Washington, 126 (2), 137-150.
  4. ^ Carnevale, Giorgio; Godfrey, Stephen J.; Pietsch, Theodore W. (2011-11-01). "Stargazer (Teleostei, Uranoscopidae) cranial remains from the Miocene Calvert Cliffs, Maryland, U.S.A. (St. Marys Formation, Chesapeake Group)". Journal of Vertebrate Paleontology. 31 (6): 1200–1209. doi:10.1080/02724634.2011.606856. ISSN 0272-4634. S2CID 196608143.
  5. ^ Aulophyseter at Fossilworks.org
  6. ^ Fuller, Anna J.; Godfrey, Stephen J. (2007-06-12). "A late Miocene ziphiid (Messapicetus sp.: Odontoceti: Cetacea) from the St. Marys Formation of Calvert Cliffs, Maryland". Journal of Vertebrate Paleontology. 27 (2): 535–540. doi:10.1671/0272-4634(2007)27[535:ALMZMS]2.0.CO;2. ISSN 0272-4634. S2CID 85606021.
  7. ^ Fuller, Anna J.; Godfrey, Stephen J. (2007-06-12). "A late Miocene ziphiid (Messapicetus sp.: Odontoceti: Cetacea) from the St. Marys Formation of Calvert cliffs, Maryland". Journal of Vertebrate Paleontology. 27 (2): 535–540. doi:10.1671/0272-4634(2007)27[535:almzms]2.0.co;2. ISSN 0272-4634. S2CID 85606021.
  8. ^ Godfrey, Stephen J.; Barnes, Lawrence G. (2008-06-12). "A new genus and species of late Miocene pontoporiid dolphin (Cetacea: Odontoceti) from the St. Marys Formation in Maryland". Journal of Vertebrate Paleontology. 28 (2): 520–528. doi:10.1671/0272-4634(2008)28[520:ANGASO]2.0.CO;2. ISSN 0272-4634. S2CID 86216551.
  9. ^ a b c d e f g Eshelman, R. Terrestrial Mammal Remains from the Miocene Chesapeake Group of Calvert Cliffs, Maryland, and Comparisons With Miocene.


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