El Doctor Formation
Geologic formation in Mexico
From Wikipedia, the free encyclopedia
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]
| El Doctor Formation | |
|---|---|
| Stratigraphic range: Albian-Cenomanian ~ | |
| Type | Formation |
| Sub-units | La Negra Member |
| Lithology | |
| Primary | Lime mudstone |
| Location | |
| Coordinates | 20.8°N 99.3°W |
| Approximate paleocoordinates | 18.9°N 64.5°W |
| Region | Hidalgo |
| Country | Mexico |
  El Doctor Formation (Mexico)  El Doctor Formation (Hidalgo) | |
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][2]
- 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.