El Doctor Formation Explained

El Doctor Formation
Type:	Formation
Period:	Cenomanian
Age:	Albian-Cenomanian ~
Prilithology:	Lime mudstone
Region:	Hidalgo
Coordinates:	20.8°N -99.3°W
Paleocoordinates:	18.9°N -64.5°W
Subunits:	La Negra Member

The El Doctor Formation is a geologic formation in Mexico. It preserves fossils dating back to the Albian and Cenomanian stages of the Cretaceous period.^[1] Ammonite fossils show that age of Late Albian is more likely.^[2]

Description

The light grey micritic limestone sequence with intercalated black chert lenses was deposited in an open marine basin with a hypersaline and/or poorly oxygenated bottom.^[1]

Fossil content

The formation has provided the following fossils:^{[1] [3] [4] [5]}

Fish

• Squalicorax falcatus
• Ptychodus decurrens
• Rajiformes^[6]
• Enchodus zimapanensis^[7]
• Xeneichthys yanesi
• Heckelichthys preopercularis
• Motlayoichthys sergioi
• Nunaneichthys mexicanus
• Ichthyotringa mexicana
• Muhichthys cordobai
• Dalgoichthys tropicalis
• Handuichthys interopercularis
• Pseudomonocentris microspinosus
• Araripichthys sp.
• Vinctifer sp.
• Pachyrhizodus sp.
• cf. Tselfatia
• Pycnodontiformes
• Cladocyclidae
• Elopiformes
• Gonorhynchiformes
• Mawsoniidae^[8]

Arthropods

• Aeger hidalguensis
• Polzia eldoctorensis^[9]
• Victoriacaris muhiensis^[9]
• Palinurus sp.

Ammonites

• Mortoniceras sp.
• Hamites aff. renzi
• Beudanticeras sp.

Echinoderms

• Echinoidea
• Crinoidea

See also

• List of fossiliferous stratigraphic units in Mexico
  • Sierra Madre Formation

References

Bibliography

Notes and References

1. http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&collection_no=135815 El Doctor Formation
2. López-Palomino . Isabel . González-Rodríguez . Katia Adriana . Schultze . Hans-Peter . Palma-Ramírez . Arturo . Contreras-Cruz . Diana . 2021-11-01 . Ammonites from the La Negra Facies (El Doctor Formation, late Albian) of the Muhi Quarry, Hidalgo, central Mexico . Journal of South American Earth Sciences . 111 . 103400 . 10.1016/j.jsames.2021.103400 . 2021JSAES.11103400L . 0895-9811.
3. Feldmann et al., 2007
4. Arratia . Gloria . González-Rodrígue . Katia . 17 July 2024 . A New Intriguing Teleost from the Albian Muhi Quarry, Central Mexico, and Early Euteleostean Diversification . Diversity . 16 . 7 . 414 . 10.3390/d16070414 . free.
5. Rodríguez . Katia González . Fielitz . Christopher . 2016 . CRETACEOUS OSTEICHTHYAN FISH ASSEMBLAGES FROM MEXICO . Cretaceous Period: Biotic Diversity and Biogeography. New Mexico Museum of Natural History and Science Bulletin . 71.
6. Book: González-Rodríguez . K.A. . Mesozoic Fishes 5 – Global Diversity and Evolution . Espinosa-Arrubarrena . K. . González-Barba . G. . Verlag Dr. Friedrich Pfeil . 2013 . 978-3-89937-159-8 . Arratia . G. . München . 9–34 . An overview of the Mexican fossil fish record . Schultze . H.-P. . Wilson . M.V.H. . http://www.pfeil-verlag.de/wp-content/uploads/2015/05/4_59d01.pdf.
7. Fielitz & González Rodríguez, 2010
8. Schultze . Hans-Peter . González-Rodríguez . Katia Adriana . 2016-04-15 . Actinistian gular plates from the Cretaceous of Mexico and the problems assigning gular plates taxonomically . Fossil Record . 19 . 2 . 101–117 . 10.5194/fr-19-101-2016 . free . 2016FossR..19..101S . 2193-0074.
9. Hegna et al., 2014