Gavialidae

Superregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Subdivisio: Pseudosuchia
Superordo: Crocodylomorpha
Ordo: Crocodilia
Subordo: Eusuchia

Familia: Gavialidae
Subfamiliae (2 + 1†): Gavialinae - Tomistominae - †Gryposuchinae
Overview of genera (2)

Gavialis – Tomistoma
+ fossil genera
Name

Gavialidae Adams, 1854
Type genus: Gavialis Oppel, 1811

Primary references

Manual Nat. Hist.:70.

Additional references

Hoser, R. 2012: A review of the taxonomy of the living crocodiles including the description of three new tribes, a new genus, and two new species. Australasian journal of herpetology, (14): 9–16. PDF of whole issue Reference page. [the author places the two extant genera, Gavialis and Tomistoma, in a "new tribe" Gavialini of family Crocodylidae, and he erroneously claims authorship of the "new tribe" (see ZooBank: 77BC8123-7F44-4DBE-A307-F7748196DC28)]

Vernacular names
Deutsch: Gaviale
English: Gharial
suomi: Gaviaali
français: Gavial
hrvatski: Gavijal
magyar: Gaviálfélék
日本語: ガビアル亜科
Nederlands: Gavialen
norsk: Gangesgavial
português: Gavial
svenska: Gavial
ไทย: ตะโขง
Tiếng Việt: Họ Cá sấu Ấn Độ

Gavialidae is a family of large semiaquatic reptiles, resembling crocodiles, but with much thinner snouts. The thin snout is used to catch fish. Gavialids lack the jaw strength to capture the large mammalian prey favoured by crocodiles and alligators of similar size.[1] Gavialidae consists of only two extant (living) members from Asia, the gharial (Gavialis gangeticus) and the false gharial (Tomistoma schlegelii), although many extinct members are known from a broader range.

Taxonomy

The family Gavialidae was proposed by Arthur Adams in 1854 for reptiles with a very long and slender muzzle, webbed feet and nearly equal teeth.[2] It is currently recognized as a crown group,[3] meaning that it only includes the last common ancestor of all extant (living) gavialids (the gharial and false gharial) and their descendants (living or extinct).

Traditionally, crocodiles and alligators were considered more closely related and grouped together in the clade Brevirostres, to the exclusion of the gharials. This classification was based on morphological studies primarily focused on analyzing skeletal traits of living and extinct fossil species.[4] However, recent molecular studies using DNA sequencing have rejected Brevirostres upon finding the crocodiles and gavialids to be more closely related than the alligators.[5][6][7][3][8] The new clade Longirostres was named by Harshman et al. in 2003.[5]

In addition, these recent molecular DNA studies consistently indicate that the false gharial (Tomistoma) (and by inference other related extinct forms) traditionally viewed as belonging to the crocodylian subfamily Tomistominae actually belong to Gavialoidea (and Gavialidae).[5][9][10][6][7][3][8] As its name suggests, the false gharial was once thought to be only distantly related to the gharial despite its similar appearance. The false gharial and other tomistomines were traditionally classified within the superfamily Crocodyloidea as close relatives of crocodiles, based solely on morphological evidence.[9]

A 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data established the inter-relationships within Crocodilia,[3] which was expanded upon in 2021 by Hekkala et al. using paleogenomics by extracting DNA from the extinct Voay.[8] The tip dating analysis resolved the extinct Thoracosaurus and similar extinct close relatives ("thoracosaurs") as outside of Gavialoidea due to the large time difference. They concluded that that the only possible explanation for the morpholigcal data placing thoracosaurs within the gharial lineage was a significant amount of homoplastic convergence between thoracosaurs and Gavialis.[3]

The below cladogram from latest study shows Gavialidae's placement within Crocodylia:

Crocodylia

Alligatoroidea   extinct basal Alligatoroids†   Alligatoridae Caimaninae     Caiman     Melanosuchus       Paleosuchus     Alligatorinae Alligator   (crown group) (stem-based group) Longirostres Crocodyloidea   "Crocodylus" megarhinus†   Crocodylidae   Crocodylus       Mecistops     Osteolaemus     (crown group) (stem-based group) Gavialoidea   Kentisuchus†         Maroccosuchus†     Paratomistoma†         Dollosuchoides†       Tomistoma cairense†   Gavialidae   Gavialis     Tomistoma   (crown group)       (stem-based group) (crown group)

(crown group)

Here is a more detailed cladogram that shows the proposed phylogeny of Gavialidae including extinct members:[3]

Gavialidae	Gavialis gangeticus Gharial     Gavialis bengawanicus†       Gavialis browni†       Gryposuchus colombianus†       Ikanogavialis†         Gryposuchus pachakamue†     Piscogavialis†         Harpacochampsa†           Toyotamaphimeia†     Penghusuchus†       Gavialosuchus†           Tomistoma lusitanica†     Tomistoma schlegelii False gharial

 
 
Species list
See also: List of crocodilians

Family Gavialidae

Subfamily Tomistominae
Genus Tomistoma
Tomistoma schlegelii, false gharial or Malayan gharial
†Tomistoma lusitanica
Genus †Rhamphosuchus
Genus †Thecachampsa
Subfamily Gavialinae
Genus Gavialis
Gavialis gangeticus, gharial
†Gavialis bengawanicus
Additional genera
Genus †Aktiogavialis
Genus †Gryposuchus? (may by paraphyletic)[3]
Genus †Hesperogavialis
Genus †Siquisiquesuchus
Genus †Ikanogavialis
Genus †Piscogavialis
Genus †Harpacochampsa
Genus †Toyotamaphimeia
Genus †Penghusuchus
Genus †Gavialosuchus

† Indicates extinct group
Extant species gallery

Gharial (Gavialis gangeticus)

False gharial (Tomistoma schlegelii)

References

Magnusson, William E. (1998). Cogger, H.G.; Zweifel, R.G. (eds.). Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. pp. 229–230. ISBN 978-0-12-178560-4.
Adams, A. (1854). "II. Order – Emydosaurians (Emydosauria)". In Adams, A.; Baikie, W. B.; Barron, C. (eds.). A Manual of Natural History, for the Use of Travellers: Being a Description of the Families of the Animal and Vegetable Kingdoms: with Remarks on the Practical Study of Geology and Meteorology. London: John Van Voorst. pp. 70–71.
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.
Holliday, Casey M.; Gardner, Nicholas M. (2012). Farke, Andrew A (ed.). "A new eusuchian crocodyliform with novel cranial integument and its significance for the origin and evolution of Crocodylia". PLOS ONE. 7 (1): e30471. Bibcode:2012PLoSO...730471H. doi:10.1371/journal.pone.0030471. PMC 3269432. PMID 22303441.
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" (PDF). Systematic Biology. 52 (3): 386–402. doi:10.1080/10635150309323. PMID 12775527.
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.
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.
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.
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.
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.