St. Marys Formation

The St. Marys Formation is a geologic formation in Maryland and Virginia, United States. It preserves fossils dating back to the Miocene Epoch of the Neogene period. It is the youngest Miocene formation present in the Calvert Cliffs and is part of the Chesapeake Group.

St. Marys Formation
Stratigraphic range: Neogene
TypeFormation
Unit ofChesapeake Group
UnderliesEastover Formation
OverliesChoptank Formation
Location
Region Maryland
 Virginia
Country United States

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.
Notorhynchus primigenius from the Calvert Formation
 [1]
Hexanchus H. gigas A species of cow shark. This species is extremely rare in this formation.
Hexanchus gigas teeth (not from St. Marys Formation)
 [1]
Squalus Commonly known as the spurdog. [1]
Squatina Commonly known as the angel shark. [1]
Rhincodon R. typus Commonly known as the whale shark. This species is extremely rare in this formation.
Modern Rhincodon typus teeth
 [1]
Carcharodon C. hastalis Putative ancestor to the extant great white shark
Carcharodon hastalis from the Calvert Formation
 [1]
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.
Carcharomodus escheri teeth from Germany
 [1]
Otodus O. megalodon This is the largest shark known to have existed.
C. megalodon from Chile
 [1]
Alopias A. latidens This species may be synonymous with the extant common thresher shark.
Alopias latidens from the Old Church Formation
 [1]
Mustelus Commonly known as smooth-hounds [1]
Hemipristis H. serra Commonly known as the snaggletooth shark. It is related to the extant snaggletooth shark.
Hemipristis serra teeth (Bone Valley)
 [1]
Carcharhinus C. falciformus Commonly known as the silky shark.
Carcharhinus falciformis upper teeth (modern)
 [1]
C. leucas Commonly known as the bull shark
Carcharhinus leucas teeth (modern)
 [1]
C. perezii Commonly known as the Caribbean reef shark
Carcharhinus perezii upper teeth (modern)
 [1]
C. priscus An extinct requiem shark [1]
C. plumbeus Commonly known as the sandbar shark
Carcharhinus plumbeus upper teeth (modern)
 [1]
Negaprion N. brevrostris Commonly known as the lemon shark
Negaprion brevirostris upper teeth
 [1]
Rhizoprionodon Commonly known as the sharpnose shark [1]
Pteromylaeus Commonly known as the bull ray [1]
Aetobatus Commonly known as the eagle ray [1]
Bony fish
Genus Notes Image Ref.
Acipenseridae gen. indet.
Extant Japanese sturgeon (Acipenser schrenckii)
 [1]
Lepisosteus
Extant spotted gar (Lepisosteus oculatus)
 [1]
Amia cf. A. calva
Extant Amia calva
 [1]
Alosa
Extant Alosa maeotica
 [1]
Ictalurus
Drawing of extant Ictalurus punctatus
 [1]
Merluccius
Drawing of extant Merluccius merluccius
 [1]
Belone B. countermani
Extant Belona belona
 [1][2]
Prionotus
Extant bandtail searobin (Prionotus ophryas)
 [1]
Agonidae gen. indet.
Extant Agonus cataphractus
 [1]
"Paralbula" "P." dorisiae [1]
Lagodon
Extant Lagodon rhomboides
 [1]
Stenotomus
Extant Stenotomus chrysops
 [1]
Pogonias
Extant black drum
 [1]
Sciaenops
Extant Sciaenops ocellatus
 [1]
Tautoga
Extant Tautoga onitis
 [1]
Astroscopus A. countermani
Artists rendition of Astroscopus countermani
 [3][1]
Sphyraena
Extant school of Sphyraena barracuda
 [1]
Istiophoridae gen. indet.
Extant Atlantic blue marlin
 [1]
Reptiles
Genus Species Notes Image Ref.
Thecachampsa T. antiquus A Tomistominae
Thecachampsa sp. Vertebra possibly derived from this formation
 [1]
Sea mammals
Type Genus Species Notes Image Ref.
Sirenians (sea cows) Metaxytherium M. floridanum
Metaxytherium floridanum skeleton
 [1]
Cetaceans (whales, dolphins and porpoises) Aulophyseter A. mediatlanticus A sperm whale
Artists depiction of Aulophyseter
 [4]
Lophocetus L. calvertensis [5]
Messapicetus
Messapicetus gregarius and M. longirostris skull diagrams
 [6]
Stenasodelphis S. russellae [7]
Terrestrial mammals
Name Notes Images Ref.
Procamelus cf. P. minor
Fossilized Procamelus mummy from Oklahoma
 [8]
Desmathyus [8]
Tapirus
Extant South American tapir (Tapirus terrestris)
 [8]
Neohipparion lenticulare
Skeleton and artists rendition of Neohipparion
 [8]
Equidae indet. Larger than Parahippus [8]
Rhinoceratidae [8]
Cormohipparion
Cranium of Cormohipparion occidentale
 [8]

See also

References
  1. 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.
  2. 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.
  3. 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.
  4. Aulophyseter at Fossilworks.org
  5. 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.
  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. 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.
  8. Eshelman, R. Terrestrial Mammal Remains from the Miocene Chesapeake Group of Calvert Cliffs, Maryland, and Comparisons With Miocene.


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