Sabinal Formation

Sabinal Formation
Stratigraphic range: Kimmeridgian to Valanginian PreꞒ Ꞓ O S D C P T J K Pg N
Type	sedimentary
Unit of	Tlaxiaco Basin
Underlies	Tlaxiaco Formation
Overlies	Consuelo Group, Tecocoyuncan Group
Lithology
Primary	Shale
Other	Mudstone, wackestone, marl
Location
Coordinates	17°18′N97°42′W / 17.3°N 97.7°W / 17.3; -97.7
Approximate paleocoordinates	11°36′N49°42′W / 11.6°N 49.7°W / 11.6; -49.7
Region	Oaxaca
Country	Mexico
Sabinal Formation (Mexico)

The Sabinal Formation is a Late Jurassic and Early Cretaceous-aged geological formation in Oaxaca, Mexico. It preserves a highly diverse marine fauna. ^{[1] [2]}

It was initially thought to only encompass the Late Jurassic (Kimmeridgian & Tithonian), but more recent studies have redefined it to cover the earliest Cretaceous (Berriasian & Valanginian) as well. It is part of the Tlaxiaco Basin, a prominent structural basin in southern Mexico that accumulated both continental and marine sediments between the Early Jurassic and the Paleogene. ^[2] The most prolific site of the formation is the Kimmeridgian-aged Llano Yosobe site near Tlaxiaco. ^[1]

Vertebrate paleobiota

Cartilaginous fish

Cartilaginous fish of the Sabinal Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Planohybodus	P. sp.	Yosobé	Kimmeridgian	Teeth	A hybodont. [1]

Ray-finned fish

Ray-finned fish of the Sabinal Formation'
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Belonostomus	B. ornatus	Cerro de la Virgen	Berriasian		An aspidorhynchid. [3] [4]
Gyrodus	G. sp.	Yosobé	Kimmeridgian	Teeth, partial skeleton	A pycnodont. The most abundant vertebrate fossil in the formation. [1]
Nhanulepisosteus	N. mexicanus	Yosobé	Kimmeridgian	Partial cranium	A gar, the earliest known from the fossil record. [5]
Otomitla	O. mexicana	Cerro de la Virgen	Berriasian		An ichthyodectiform. [4]
	O. speciosa
Pleuropholidae indet.		Yosobé	Kimmeridgian	Trunk with scales	A pleuropholid. [1]
Pleuropholis	P. cisnerosorum	Yosobé	Kimmeridgian	Partial skull	A pleuropholid. [6]
? Thrissops	T. sp.	Cerro de la Virgen	Berriasian		An ichthyodectiform. [4]
Vinctifer	V. ferrusquiai	Yosobé	Kimmeridgian	Parts of head and trunk	An aspidorhynchid. [7]

Reptiles

Crocodylomorphs

Crocodylomorphs of the Sabinal Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Maledictosuchus	M. nuyivijanan	Yosobé	Kimmeridgian	Nearly complete cranium, jaws, and some vertebrae	A metriorhynchid thalattosuchian. First record of this genus outside Europe. [8]
Torvoneustes	T. mexicanus (=Plesiosaurus mexicanus, Cricosaurus mexicanus)	Unknown, but most likely Yosobé	Kimmeridgian	Parts of cranium and jaws	A metriorhynchid thalattosuchian. First record of this genus outside Europe. [9]

Turtles

Turtles of the Sabinal Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Notoemys	N. tlaxiacoensis	Yosobé	Kimmeridgian	Nearly complete carapace with plastron	A stem-group sideneck turtle. [10] [11]

Plesiosaurs

Plesiosaurs of the Sabinal Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Liopleurodon	L. sp.	Yosobé	Kimmeridgian	Partial jaw with teeth	A pliosaur. First record of this genus outside Europe. [12]
Pliosauridae indet.		Yosobé	Kimmeridgian	Vertebrae and ribs	An indeterminate pliosaur. Remains appear to have been scavenged by Planohybodus . [12]

Ichthyosauria

Ichthyosaurs of the Sabinal Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Ophthalmosauridae indet.		Yosobé	Kimmeridgian	Vertebrae	An ophthalmosaurid ichthyosaur.

References

1. Alvarado-Ortega, Jesús; Barrientos-Lara, Jair Israel; Espinosa-Arrubarrena, Luis; Pilar Melgarejo-Damián, María del (2014-07-09). "Late Jurassic marine vertebrates from Tlaxiaco, Oaxaca State, southern Mexico". Palaeontologia Electronica. doi:10.26879/454 . Retrieved 2025-01-27.
2. Zell, Patrick; Stinnesbeck, Wolfgang; Beckmann, Seija; Adatte, Thierry; Hering, Fabio (2015-10-01). "The Berriasian–Valanginian (Early Cretaceous) boundary transition at Santa Catarina Ticuá, Oaxaca state, southern Mexico: Ammonites, bivalves, calpionellids and their paleobiogeographic significance" . Journal of South American Earth Sciences. 62: 33–57. Bibcode:2015JSAES..62...33Z. doi:10.1016/j.jsames.2015.04.009. ISSN   0895-9811.
3. Van Vranken, Nathan E.; Fielitz, Christopher; Ebersole, Jun A. (2019-09-13). "New occurrences of Belonostomus (Teleostomorpha: Aspidorhynchidae) from the Late Cretaceous of the North American Gulf Coastal Plain, USA". Palaeontologia Electronica. doi: 10.26879/983 . Retrieved 2025-01-27.
4. GONZÁLEZ-RODRÍGUEZ, KATIA A.; FIELITZ, CHRISTOPHER; BRAVO-CUEVAS, VICTOR M.; BAÑOS-RODRÍGUEZ, ROCÍO E. (2016). "CRETACEOUS OSTEICHTHYAN FISH ASSEMBLAGES FROM MEXICO". New Mexico Museum of Natural History and Science Bulletin (71).
5. Brito, Paulo M.; Alvarado-Ortega, Jésus; Meunier, François J. (2017-12-19). "Earliest known lepisosteoid extends the range of anatomically modern gars to the Late Jurassic". Scientific Reports. 7 (1): 17830. Bibcode:2017NatSR...717830B. doi:10.1038/s41598-017-17984-w. ISSN   2045-2322. PMC   5736718 . PMID   29259200.
6. Alvarado-Ortega, Jesús; Brito, Paulo M. (2016-09-02). "A Jurassic pleuropholid fish (Teleostei, Pleuropholidae) in the Tethys Sea domain of North America" . Journal of Vertebrate Paleontology. 36 (5): e1201767. Bibcode:2016JVPal..36E1767A. doi:10.1080/02724634.2016.1201767. ISSN   0272-4634.
7. Cantalice, Kleyton M.; Alvarado-Ortega, Jesús; Brito, Paulo M.; Cantalice, Kleyton M.; Alvarado-Ortega, Jesús; Brito, Paulo M. (2018). "On the occurrence of Vinctifer ferrusquiai sp. nov. (Actinopterygii, Aspidorhynchiformes) in the Kimmeridgian (Late Jurassic) deposits near Tlaxiaco, Oaxaca, southern Mexico". Revista Mexicana de Ciencias Geológicas. 35 (2): 179–187. Bibcode:2018RMxCG..35..179C. doi: 10.22201/cgeo.20072902e.2018.2.713 . ISSN   1026-8774.
8. Barrientos-Lara, Jair I.; Alvarado-Ortega, Jesús; Fernández, Marta S. (2018-07-04). "The marine crocodile Maledictosuchus (Thalattosuchia, Metriorhynchidae) from the Kimmeridgian deposits of Tlaxiaco, Oaxaca, southern Mexico" . Journal of Vertebrate Paleontology. 38 (4): (1)–(14). doi:10.1080/02724634.2018.1478419. hdl:11336/82460. ISSN   0272-4634.
9. Barriento Lara, Jair Israel; Herrera, Laura Yanina; Fernández, Marta Susana; Alvarado Ortega, Jesús (2016). "Occurrence of Torvoneustes (crocodylomorpha, metriorhynchidae) in marine jurassic deposits of Oaxaca, Mexico". Revista Brasileira de Paleontologia. 19 (3): 415–424. doi:10.4072/rbp.2016.3.07. hdl: 11336/130337 . ISSN   1519-7530.
10. López-Conde, Oliver A.; Sterli, Juliana; Alvarado-Ortega, Jesus; Chavarría-Arellano, María L. (2017). "A new platychelyid turtle (Pan-Pleurodira) from the Late Jurassic (Kimmeridgian) of Oaxaca, Mexico" . Papers in Palaeontology. 3 (2): 161–174. Bibcode:2017PPal....3..161L. doi:10.1002/spp2.1069. ISSN   2056-2802.
11. Conde, Oliver A. López; Ortega, Jesús Alvarado (2021-12-01). "New remains of Notoemys tlaxiacoensis from the Llano Yosobé, Sabinal Formation (Upper Jurassic, Kimmeridgian), Oaxaca, Mexico" . Revista Paleontología Mexicana. 10 (2): 123–128. doi:10.22201/igl.05437652e.2021.10.2.306. ISSN   2007-5189.
12. Barrientos-Lara, Jair Israel; Fernández, Marta S.; Alvarado-Ortega, Jesús; Barrientos-Lara, Jair Israel; Fernández, Marta S.; Alvarado-Ortega, Jesús (2015). "Kimmeridgian pliosaurids (Sauropterygia, Plesiosauria) from Tlaxiaco, Oaxaca, southern Mexic". Revista Mexicana de Ciencias Geológicas. 32 (2): 293–304. ISSN   1026-8774.