Tomistoma cairense

Tomistoma cairense
Temporal range: Eocene: Lutetian, 47.8–41.2 Ma[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Family: Gavialidae
Genus: Tomistoma
Species:
T. cairense
Binomial name
Tomistoma cairense
Müller, 1927[2]

Tomistoma cairense is an extinct species of gavialoid crocodilian from the Lutetian stage of the Eocene era.[3] It lived in North East Africa, especially Egypt.[3] Remains of T. cairense have been found in the Mokattam Formation, in Mokattam, Egypt.[4] Tomistoma cairense did not have a Maxilla process within their lacrimal gland, whereas all extant (living) crocodilians do.[5]

Below is a cladogram based morphological studies comparing skeletal features that shows Tomistoma cairense as a member of Tomistominae, related to the false gharial:[6]

Crocodylidae

Based on morphological studies of extinct taxa, the tomistomines (including the living false gharial) were long thought to be classified as crocodiles and not closely related to gavialoids.[7] However, recent molecular studies using DNA sequencing have consistently indicated that the false gharial (Tomistoma) (and by inference other related extinct forms in Tomistominae) actually belong to Gavialoidea (and Gavialidae).[8][9][10][11][12][13][14]

Below is a cladogram from a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data that shows Tomistoma cairense as a gavialoid, more basal than the last common ancestor to both the gharial and the false gharial:[13]

Gavialoidea
(stem-based group)

Tomistoma cairense may need to be reclassified to a new genera, as studies have shown that its inclusion makes Tomistoma out to be paraphyletic.[6][13]

  1. ^ Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ. 9: e12094. doi:10.7717/peerj.12094. PMC 8428266. PMID 34567843.
  2. ^ "Crocodyloidea". www.helsinki.fi. Retrieved 4 March 2017.
  3. ^ a b Jouve, Stéphane (2016). "A new basal tomistomine (Crocodylia, Crocodyloidea) from Issel (Middle Eocene; France): Palaeobiogeography of basal tomistomines and palaeogeographic consequences". Zoological Journal of the Linnean Society. 177: 165–182. doi:10.1111/zoj.12357. Retrieved 4 March 2017.
  4. ^ BROCHU, CHRISTOPHER A. (1997). "Morphology, Fossils, Divergence Timing, and the Phylogenetic Relationships of Gavialis". Systematic Biology. 46 (3). Department of Geological Sciences, University of Texas: 479–522. doi:10.1093/SYSBIO/46.3.479. PMID 11975331. S2CID 11011122.
  5. ^ BROCHU, CHRISTOPHER A. (2007). "Systematics and Taxonomy of Eocene Tomistomine Crocodylians from Britain and Northern Europe". Palaeontology. 50 (4): 917–928. doi:10.1111/j.1475-4983.2007.00679.x. Retrieved 4 March 2017.
  6. ^ a b Iijima, Masaya; Momohara, Arata; Kobayashi, Yoshitsugu; Hayashi, Shoji; Ikeda, Tadahiro; Taruno, Hiroyuki; Watanabe, Katsunori; Tanimoto, Masahiro; Furui, Sora (2018-05-01). "Toyotamaphimeia cf. machikanensis (Crocodylia, Tomistominae) from the Middle Pleistocene of Osaka, Japan, and crocodylian survivorship through the Pliocene-Pleistocene climatic oscillations". Palaeogeography, Palaeoclimatology, Palaeoecology. 496: 346–360. Bibcode:2018PPP...496..346I. doi:10.1016/j.palaeo.2018.02.002. ISSN 0031-0182.
  7. ^ Brochu, C.A.; Gingerich, P.D. (2000). "New tomistomine crocodylian from the Middle Eocene (Bartonian) of Wadi Hitan, Fayum Province, Egypt". University of Michigan Contributions from the Museum of Paleontology. 30 (10): 251–268.
  8. ^ Harshman, J.; Huddleston, C. J.; Bollback, J. P.; Parsons, T. J.; Braun, M. J. (2003). "True and false gharials: A nuclear gene phylogeny of crocodylia". Systematic Biology. 52 (3): 386–402. doi:10.1080/10635150309323. PMID 12775527.
  9. ^ Gatesy, Jorge; Amato, G.; Norell, M.; DeSalle, R.; Hayashi, C. (2003). "Combined support for wholesale taxic atavism in gavialine crocodylians" (PDF). Systematic Biology. 52 (3): 403–422. doi:10.1080/10635150309329. PMID 12775528.
  10. ^ Willis, R. E.; McAliley, L. R.; Neeley, E. D.; Densmore Ld, L. D. (June 2007). "Evidence for placing the false gharial (Tomistoma schlegelii) into the family Gavialidae: Inferences from nuclear gene sequences". Molecular Phylogenetics and Evolution. 43 (3): 787–794. doi:10.1016/j.ympev.2007.02.005. PMID 17433721.
  11. ^ Gatesy, J.; Amato, G. (2008). "The rapid accumulation of consistent molecular support for intergeneric crocodylian relationships". Molecular Phylogenetics and Evolution. 48 (3): 1232–1237. doi:10.1016/j.ympev.2008.02.009. PMID 18372192.
  12. ^ Erickson, G. M.; Gignac, P. M.; Steppan, S. J.; Lappin, A. K.; Vliet, K. A.; Brueggen, J. A.; Inouye, B. D.; Kledzik, D.; Webb, G. J. W. (2012). Claessens, Leon (ed.). "Insights into the ecology and evolutionary success of crocodilians revealed through bite-force and tooth-pressure experimentation". PLOS ONE. 7 (3): e31781. Bibcode:2012PLoSO...731781E. doi:10.1371/journal.pone.0031781. PMC 3303775. PMID 22431965.
  13. ^ a b c Michael S. Y. Lee; Adam M. Yates (27 June 2018). "Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil". Proceedings of the Royal Society B. 285 (1881). doi:10.1098/rspb.2018.1071. PMC 6030529. PMID 30051855.
  14. ^ Hekkala, E.; Gatesy, J.; Narechania, A.; Meredith, R.; Russello, M.; Aardema, M. L.; Jensen, E.; Montanari, S.; Brochu, C.; Norell, M.; Amato, G. (2021-04-27). "Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus". Communications Biology. 4 (1): 505. doi:10.1038/s42003-021-02017-0. ISSN 2399-3642. PMC 8079395. PMID 33907305.