St. Marys Formation

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

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. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 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. 1 2 3 4 5 6 7 Eshelman, R. Terrestrial Mammal Remains from the Miocene Chesapeake Group of Calvert Cliffs, Maryland, and Comparisons With Miocene.