Thalattosuchia
Thalattosuchia is a clade of marine crocodylomorphs from the Early Jurassic to the Early Cretaceous that had a cosmopolitan distribution.[2] They are colloquially referred to as marine crocodiles or sea crocodiles, though they are not members of Crocodilia and records from Thailand and China suggest that some members lived in freshwater.[3] The clade contains two major subgroupings, the Teleosauroidea and Metriorhynchoidea. Teleosauroids are not greatly specialised for oceanic life, with back osteoderms similar to other crocodyliformes. Within Metriorhynchoidea, the Metriorhynchidae displayed extreme adaptions for life in the open ocean, including the transformation of limbs into flippers, the development of a tail fluke, and smooth, scaleless skin,[4] and probably gave live birth, seemingly uniquely among archosaurs.[5]
Thalattosuchians Temporal range: Pliensbachian - Early Aptian | |
---|---|
Platysuchus,(Teleosauridae, Teleosauroidea) | |
Cricosaurus (Metriorhynchidae, Metriorhynchoidea) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Pseudosuchia |
Clade: | Crocodylomorpha |
Clade: | Crocodyliformes |
Suborder: | †Thalattosuchia Fraas, 1901[1] |
Superfamilies | |
Taxonomy
The term Thalattosuchia was coined by Fraas in 1901.[1] Various authors considered Thalattosuchia an infraorder or a suborder within "Mesosuchia". However, the term "Mesosuchia" is a paraphyletic group, and as such is no longer used. For consistency, the Thalattosuchia are here placed at suborder rank, although the order that contains it is unnamed. The exact phylogenetic position of Thalattosuchia is uncertain, with them either being interpreted as members of Neosuchia alongside other aquatic crocodylomorphs, or more basal members of Crocodylomorpha, with the similarities to neosuchians being as a result of convergent evolution.[6] The group consists of two major subgroupings, Teleosauroidea (containing the families Machimosauridae and Teleosauridae), and Metriorhynchoidea (containing Metriorhynchidae and some more basal taxa).[7][8]
Evolutionary history
The oldest possible records of thalattosuchians date to the Sinemurian stage of the Early Jurassic, represented by indeterminate remains from Chile and France. However, they cannot be assigned to the group with confidence as they lack diagnostic characters. The oldest confirmed member of the group is Turnersuchus from the Pliensbachian of England, which appears to be basal to both Teleosauroidea and Metriorhynchoidea.[8] In 2023 a basal teleosauroid was reported from the earliest Jurassic (Hettangian-Sinemurian) of Morocco.[9] While abundant during the Jurassic, their fossil record during the Early Cretaceous is scarce, and generally confined to low latitudes. The latest records of the group date to the Aptian.[10][11] Some members of Teleosauridae have been discovered in non-marine deposits.[3]
References
- Fraas E. 1901. Die Meerkrokodile (Thalattosuchia n. g.) eine neue Sauriergruppe der Juraformation. Jahreshefte des Vereins für vaterländische Naturkunde, Württemberg 57: 409-418.
- Alfio A. Chiarenza; Davide Foffa; Mark T. Young; Gianni Insacco; Andrea Cau; Giorgio Carnevale; Rita Catanzariti (2015). "The youngest record of metriorhynchid crocodylomorphs, with implications for the extinction of Thalattosuchia". Cretaceous Research. 56: 608–616. doi:10.1016/j.cretres.2015.07.001. hdl:2318/1537833.
- Martin, Jeremy E.; Suteethorn, S.; Lauprasert, K. (February 2019). "A new freshwater teleosaurid from the Jurassic of northeastern Thailand" (PDF). Journal of Vertebrate Paleontology. 64 (2): 239–260. doi:10.1080/02724634.2018.1549059. S2CID 91988192.
- Spindler, Frederik; Lauer, René; Tischlinger, Helmut; Mäuser, Matthias (2021-07-05). "The integument of pelagic crocodylomorphs (Thalattosuchia: Metriorhynchidae)". Palaeontologia Electronica. 24 (2): 1–41. doi:10.26879/1099. ISSN 1094-8074.
- Herrera, Y.; Fernandez, M.S.; Lamas, S.G.; Campos, L.; Talevi, M.; Gasparini, Z. (2017). "Morphology of the sacral region and reproductive strategies of Metriorhynchidae: a counter-inductive approach". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 106 (4): 247–255. doi:10.1017/S1755691016000165.
- Wilberg, Eric W. (2015-07-01). "What's in an Outgroup? The Impact of Outgroup Choice on the Phylogenetic Position of Thalattosuchia (Crocodylomorpha) and the Origin of Crocodyliformes". Systematic Biology. 64 (4): 621–637. doi:10.1093/sysbio/syv020. ISSN 1076-836X. PMID 25840332.
- Johnson, Michela M.; Young, Mark T.; Brusatte, Stephen L. (2020-10-08). "The phylogenetics of Teleosauroidea (Crocodylomorpha, Thalattosuchia) and implications for their ecology and evolution". PeerJ. 8: e9808. doi:10.7717/peerj.9808. ISSN 2167-8359. PMC 7548081.
- Wilberg, E. W.; Godoy, P. L.; Griffiths, E. F.; Turner, A. H.; Benson, R. B. J. (2023). "A new early diverging thalattosuchian (Crocodylomorpha) from the Early Jurassic (Pliensbachian) of Dorset, U.K. and implications for the origin and evolution of the group". Journal of Vertebrate Paleontology. e2161909. doi:10.1080/02724634.2022.2161909. S2CID 256149424.
- Benani, Hicham; Nehili, Ayoub; Ouzzaouit, Lalla Amina; Jouve, Stéphane; Boudad, Larbi; Masrour, Moussa; Jalil, Noureddine; Arrad, Taha Younes (February 2023). "Discovery of the teleosauroid crocodylomorph from the early Jurassic of Chaara cave, Middle Atlas of Morocco". Journal of African Earth Sciences. 198: 104804. doi:10.1016/j.jafrearsci.2022.104804.
- Young, Mark T.; Sachs, Sven (2021-09-02). "Evidence of thalattosuchian crocodylomorphs in the Portland Stone Formation (Late Jurassic) of England, and a discussion on Cretaceous teleosauroids". Historical Biology. 33 (9): 1473–1476. doi:10.1080/08912963.2019.1709453. ISSN 0891-2963. S2CID 213426116.
- Chiarenza, Alfio A.; Foffa, Davide; Young, Mark T.; Insacco, Gianni; Cau, Andrea; Carnevale, Giorgio; Catanzariti, Rita (September 2015). "The youngest record of metriorhynchid crocodylomorphs, with implications for the extinction of Thalattosuchia". Cretaceous Research. 56: 608–616. doi:10.1016/j.cretres.2015.07.001. hdl:2318/1537833.
Further reading
- Fraas, E. (1902). "Die Meer-Krocodilier (Thalattosuchia) des oberen Jura unter specieller Berücksichtigung von Dacosaurus und Geosaurus". Paleontographica 49: 1-72.
External links
- "Ancient ocean-going crocodiles mimicked whales and dolphins" at The Guardian, 20 Apr 2020