Ojo Alamo Formation
| Ojo Alamo Formation Stratigraphic range: Maastrichtian-Danian ~69–64 Ma PreЄ Є O S D C P T J K Pg N ↓ | |
|---|---|
| Type | Geological formation |
| Sub-units | Naashoibito Member, Kimbeto Member |
| Underlies | Nacimiento Formation |
| Overlies | Kirtland Formation |
| Location | |
| Region | San Juan Basin, New Mexico |
| Country |  USA |
The Ojo Alamo Formation is a geologic formation spanning the Mesozoic/Cenozoic boundary. Dinosaur remains are among the fossils that have been recovered from the formation, though all dinosaur remains come from the lowest part of the formation, the Naashoibito member (sometimes considered part of the Kirtland Formation, which dates to the late Maastrichtian stage of the Cretaceous period.[1]
The Ojo Alamo formation is divided into two subunits separated by a large unconformity—a gap in the geologic record. The lower Naashoibito member (sometimes considered part of the Kirtland Formation) was deposited during the Maastrichtian age of the Cretaceous period, specifically between about 69-68 million years ago. It overlies the De-na-zin member of the Kirtland formation, though the two are separated by another large unconformity that spans 73-69 million years of geologic time.[2] All dinosaur fossils probably come from this unit.[3]
The upper unit of the Ojo Alamo Formation is the Kimbeto Member, which was deposited mainly during the earliest Cenozoic (Danian age of the Paleogene period), between 66 and 64 million years ago.[2] Some researchers have claimed to find isolated non-avian dinosaur remains in this younger unit. If this is the case, it would represent the only known instance of a non-avian dinosaur population persisting after the Cretaceous–Paleogene extinction event. However, most scientists consider these to have been stratigraphically misinterpreted or reworked from the older Naashoibito member.[3]
Contents
1 Alamo Wash fauna
2 See also
3 References
4 Further reading
Alamo Wash fauna
The following species are known to be present in the Naashoibito Member "Alamo Wash Fauna".[4]
Lizards
- Peneteius
Fish
Myledaphus sp.
Squatirhina sp.- cf. Lepisosteus sp.
- ?Osteichthyes indet.
Amphibians
Caudata indet.
Turtles
- Aspideretoides
- Compsemys
- cf. Hoplochelys sp.
- Neurankylus
- Plastomenus
Adocus?
Basilemys?
Theropods
Dromaeosauridae sp.
Ojoraptorsaurus boerei[5]
Ornithomimidae indet.
Richardoestesia sp.
Troodontidae indet.
Tyrannosauridae indet.- aff. Tyrannosaurus rex
Alamotyrannus brinkmani? Paper regarding its discovery has not been published as of 2018.[6]
Sauropods
- Alamosaurus sanjuanensis
Ankylosaurs
- Glyptodontopelta mimus
Ankylosauridae indet.
Hadrosaurids
Saurolophinae indet.- aff. Edmontosaurus annectens
- aff. Kritosaurus navajovius
Lambeosaurinae indet. similar to Hypacrosaurus altispinus[7]
Ceratopsians
- Ojoceratops fowleri
- Torosaurus utahensis
- aff. Eotriceratops xerinsularis
Pterosaurs
- Quetzalcoatlus northropi
Mammals
- cf. Alphadon marshi
Alphadontinae indet.- Essonodon browni
- cf. Glasbius sp.
- Mesodoma formosa
- cf. Meniscoessus sp.
Multituberculata indet.- cf. Pediomyidae indet.
- cf. Alphadon marshi
See also
- List of dinosaur-bearing rock formations
References
^ Williamson, T.E. and Weil, A. (2008). "Metatherian mammals from the Naashoibito Member, Kirtland Formation, San Juan Basin, New Mexico and their biochronologic and paleobiogeographic significance. Journal of Vertebrate Paleontology, 28: 803-815.
^ ab Sullivan, R.M., and Lucas, S.G. 2006. "The Kirtlandian land-vertebrate "age" – faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America[permanent dead link]." New Mexico Museum of Natural History and Science, Bulletin 35:7-29.
^ ab Sullivan, RM (2003). "No Paleocene dinosaurs in the San Juan Basin, New Mexico". Geological Society of America Abstracts with Programs. 35 (5): 15. Retrieved 2007-07-02..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ Jasinski, S. E., Sullivan, R. M., & Lucas, S. G. (2011). Taxonomic composition of the Alamo Wash local fauna from the Upper Cretaceous Ojo Alamo Formation (Naashoibito Member) San Juan Basin, New Mexico. Bulletin, 53, 216-271.
^ Robert M. Sullivan, Steven E. Jasinski and Mark P.A. Van Tomme (2011). "A new caenagnathid Ojoraptorsaurus boerei, n. gen., n. sp. (Dinosauria, Oviraptorosauria), from the Upper Ojo Alamo Formation (Naashoibito Member), San Juan Basin, New Mexico" (PDF). Fossil Record 3. New Mexico Museum of Natural History and Science Bulletin. 53: 418–428.
^ DALMAN, S.G.; LUCAS, S.G. "A new large Tyrannosaurid Alamotyrannus brinkmani, n. gen., n. sp. (Theropoda: Tyrannosauridae), from the Upper Cretaceous Ojo Alamo Formation (Naashoibito Member), San Juan Basin, New Mexico". New Mexico Museum of Natural History and Science Bulletin. In Press.|access-date=requires|url=(help)
^ Jasinski, Steven E.; Sullivan, Robert M.; Lucas, Spencer G.; Spielmann, Justin A. "The first "lambeosaurin" (Dinosauria, Hadrosauridae, Lambeosaurinae) from the Upper Cretaceous Ojo Alamo Formation (Naashoibito Member), San Juan Basin, New Mexico: further implications for the age of the Alamo Wash local fauna". www.researchgate.com. ResearchGate. Retrieved 21 August 2016.
Further reading
Burns, Michael E. (2008). "Taxonomic utility of ankylosaur (Dinosauria, Ornithischia) osteoderms: Glyptodontopelta mimus Ford, 2000: a test case". Journal of Vertebrate Paleontology. 28 (4): 1102–1109. doi:10.1671/0272-4634-28.4.1102.
