Gavialidae

{{Short description|Family of gharial crocodylians}} {{Automatic taxobox | name = Gavialidae | fossil_range = Eocene, {{fossilrange|38|0}} | image = Indian Gharial Crocodile Digon3.JPG | image_caption = Indian gharial, ''Gavialis gangeticus'' | taxon = Gavialidae | authority = Adams, 1854 | subdivision_ranks = Subfamilies | subdivision = *Gavialinae *Tomistominae * †Gryposuchinae? }}

'''Gavialidae''' is a family of large semiaquatic crocodilians with elongated, narrow snouts. Gavialidae consists of two living species, the gharial (''Gavialis gangeticus'') and the false gharial (''Tomistoma schlegelii''), both occurring in Asia. Many extinct members are known from a broader range, including the recently extinct ''Hanyusuchus''. Gavialids are generally regarded as lacking the jaw strength to capture the large mammalian prey favoured by crocodiles and alligators of similar size so their thin snout is best used to catch fish, however the false gharial has been found to have a generalist diet with mature adults preying upon larger vertebrates, such as ungulates.<ref name=EoR>{{cite book |editor1=Cogger, H. G. |editor2=Zweifel, R. G. |author=Magnusson, W. E. |year=1998 |title=Encyclopedia of Reptiles and Amphibians |publisher= Academic Press |location=San Diego|isbn= 978-0-12-178560-4 |pages= 229–230 |chapter=}}</ref>

==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.<ref>{{cite book |author1=Adams, A. |year=1854 |title=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 |location=London |publisher=John Van Voorst |editor1=Adams, A. |editor2=Baikie, W. B. |editor3=Barron, C. |chapter=II. Order – Emydosaurians (Emydosauria) |pages=70–71 |chapter-url=https://books.google.com/books?id=71FAAAAAIAAJ&pg=PA70}}</ref> It is currently recognized as a crown group,<ref name="LeeYates2018">{{cite journal | author=Michael S. Y. Lee |author2=Adam M. Yates |date=27 June 2018 |title=Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil |journal=Proceedings of the Royal Society B |volume=285 |issue=1881 |doi=10.1098/rspb.2018.1071 |pmid=30051855 |pmc=6030529 |doi-access=free}}</ref> 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.<ref>{{cite journal | author=Holliday, Casey M. | author2=Gardner, Nicholas M. | year=2012 | title=A new eusuchian crocodyliform with novel cranial integument and its significance for the origin and evolution of Crocodylia | journal=PLOS ONE | volume=7 |issue=1 | article-number=e30471 |doi=10.1371/journal.pone.0030471 |editor1-last=Farke |editor1-first=Andrew A |pmid=22303441 |pmc=3269432 |bibcode = 2012PLoSO...730471H | doi-access=free }}</ref> However, recent molecular studies using DNA sequencing have rejected Brevirostres upon finding the crocodiles and gavialids to be more closely related than the alligators.<ref name="Harshman2003">{{cite journal |pmid=12775527 |year=2003 |last1=Harshman |first1=J. |title=True and false gharials: A nuclear gene phylogeny of crocodylia |journal=Systematic Biology |volume=52 |issue=3 |pages=386–402 |last2=Huddleston |first2=C. J. |last3=Bollback |first3=J. P. |last4=Parsons |first4=T. J. |last5=Braun |first5=M. J. |doi=10.1080/10635150309323 |doi-access=free }}</ref><ref name="Gatesy2008">{{cite journal|last1=Gatesy |first1=J. |last2=Amato |first2=G. |year=2008 |title=The rapid accumulation of consistent molecular support for intergeneric crocodylian relationships |journal=Molecular Phylogenetics and Evolution|volume=48 |issue=3 |pages=1232–1237 |doi=10.1016/j.ympev.2008.02.009|pmid=18372192}}</ref><ref name=bite>{{cite journal| author=Erickson, G. M.| author2=Gignac, P. M.| author3=Steppan, S. J.| author4=Lappin, A. K.| author5=Vliet, K. A.| author6=Brueggen, J. A.| author7=Inouye, B. D.| author8=Kledzik, D.| author9=Webb, G. J. W. | year=2012 | title=Insights into the ecology and evolutionary success of crocodilians revealed through bite-force and tooth-pressure experimentation | journal=PLOS ONE | volume=7 |issue=3 |article-number=e31781 |doi=10.1371/journal.pone.0031781|editor1-last=Claessens|editor1-first=Leon|bibcode = 2012PLoSO...731781E | pmid=22431965 | pmc=3303775| doi-access=free}}</ref><ref name="LeeYates2018"/><ref name="Hekkala2021">{{Cite journal|last1=Hekkala |first1=E. |last2=Gatesy |first2=J. |last3=Narechania |first3=A. |last4=Meredith |first4=R. |last5=Russello |first5=M. |last6=Aardema |first6=M. L. |last7=Jensen |first7=E. |last8=Montanari |first8=S. |last9=Brochu |first9=C. |last10=Norell |first10=M. |last11=Amato |first11=G. |date=2021-04-27 |title=Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus |journal=Communications Biology |language=en |volume=4 |issue=1 |page=505 |doi=10.1038/s42003-021-02017-0 |pmid=33907305 |pmc=8079395 |issn=2399-3642 |doi-access=free}}</ref> The new clade Longirostres was named by Harshman ''et al.'' in 2003.<ref name="Harshman2003"/>

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).<ref name="Harshman2003"/><ref name="Gatesy2003">{{cite journal |last=Gatesy |first=Jorge |author2=Amato, G. |author3=Norell, M. |author4=DeSalle, R. |author5= Hayashi, C. |year=2003 |title=Combined support for wholesale taxic atavism in gavialine crocodylians |journal=Systematic Biology |volume=52 |issue=3 |pages=403–422 |doi= 10.1080/10635150309329|pmid=12775528 |url=http://www.faculty.ucr.edu/~mmaduro/seminarpdf/GatesyetalSystBiol2003.pdf|doi-access=free }}</ref><ref name="Willis2007">{{Cite journal | last1 = Willis | first1 = R. E. | last2 = McAliley | first2 = L. R. | last3 = Neeley | first3 = E. D. | last4 = Densmore Ld | first4 = L. D. | title = Evidence for placing the false gharial (''Tomistoma schlegelii'') into the family Gavialidae: Inferences from nuclear gene sequences | doi = 10.1016/j.ympev.2007.02.005 | journal = Molecular Phylogenetics and Evolution | volume = 43 | issue = 3 | pages = 787–794 | date = June 2007 | pmid = 17433721}}</ref><ref name="Gatesy2008"/><ref name=bite/><ref name="LeeYates2018"/><ref name="Hekkala2021"/> 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.<ref name="Gatesy2003"/>

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,<ref name="LeeYates2018"/> which was expanded upon in 2021 by Hekkala ''et al.'' using paleogenomics by extracting DNA from the extinct ''Voay''.<ref name="Hekkala2021"/> 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 the only possible explanation for the morphological data placing thoracosaurs within the gharial lineage was a significant amount of homoplastic convergence between thoracosaurs and ''Gavialis''.<ref name="LeeYates2018"/>

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

{{clade| style=font-size:85%;line-height:85% |label1='''Crocodylia''' |sublabel1=(crown group) |1={{clade |label1=Alligatoroidea |sublabel1=(stem-based group) |1={{clade |1=extinct basal Alligatoroids{{extinct}} |label2=Alligatoridae |sublabel2=(crown group) |2={{clade |label1=Caimaninae |1={{clade |1={{clade |1=''Caiman'' 90 px |2=''Melanosuchus'' 120 px }} |2=''Paleosuchus'' 90 px }} |label2=Alligatorinae |2=''Alligator'' 100 px }} }} |label2=Longirostres |sublabel2=(crown group) |2={{clade |label1=Crocodyloidea |sublabel1=(stem-based group) |1={{clade |1=''"Crocodylus" megarhinus''{{extinct}} |label2=Crocodylidae |sublabel2=(crown group) |2={{clade |1=''Crocodylus'' 90 px |2={{clade |1=''Mecistops'' 90 px |2=''Osteolaemus'' 90 px }} }} }} |label2=Gavialoidea |sublabel2=(stem-based group) |2={{clade |1=''Kentisuchus''{{extinct}} |2={{clade |1={{clade |1=''Maroccosuchus''{{extinct}} |2=''Paratomistoma''{{extinct}} }} |2={{clade |1=''Dollosuchoides''{{extinct}} |2={{clade |1=''Tomistoma cairense''{{extinct}} |label2='''Gavialidae''' |sublabel2=(crown group) |2={{clade |1=''Gavialis'' 110 px |2=''Tomistoma'' 90 px }} }} }} }} }} }} }} }}

Here is a more detailed cladogram that shows the proposed phylogeny of Gavialidae including extinct members:<ref name="Iijima2022">{{cite journal | vauthors = Iijima M, Qiao Y, Lin W, Peng Y, Yoneda M, Liu J |year=2022 | title = An intermediate crocodylian linking two extant gharials from the Bronze Age of China and its human-induced extinction |journal=Proceedings of the Royal Society B: Biological Sciences |volume=289 |issue=1970 |article-number=20220085 |doi=10.1098/rspb.2022.0085| pmid=35259993 |doi-access=free |pmc=8905159 }}</ref> {{clade| style=font-size:85%;line-height:85% |1={{clade |1='''Crocodyloidea''' |label2='''Gavialoidea''' |2={{clade |1={{clade |1={{extinct}}''Maroccosuchus zennaroi'' |2={{extinct}}''Megadontosuchus arduini'' |3={{extinct}}''Dollosuchoides densmorei'' |4={{extinct}}''Xaymacachampsa kugleri'' |5={{clade |1={{extinct}}''Kentisuchus astrei'' |2={{extinct}}''Kentisuchus spenceri'' }}}} |label2='''Gavialidae''' |2={{clade |1={{extinct}}''Tomistoma cairense'' |2={{extinct}}''Tomistoma coppensi'' |3={{extinct}}''Maomingosuchus petrolica'' |label4='''Tomistominae''' |4={{clade |1=''Tomistoma schlegelii'', '''false gharial''' |2={{clade |1={{extinct}}''Tomistoma lusitanicum'' |2={{clade |1={{extinct}}''Gavialosuchus eggenburgensis'' |2={{clade |1={{extinct}}''Melitosaurus champsoides'' |2={{extinct}}''Tomistoma calaritanum'' |3={{extinct}}''Tomistoma gaudense'' |4={{clade |1={{extinct}}''Thecachampsa carolinensis'' |2={{extinct}}''Thecachampsa antiqua'' }}}}}}}}}} |label5='''Gavialinae''' |5={{clade |1={{extinct}}''Paratomistoma courti'' |2={{clade |1={{clade |1={{extinct}}''Penghusuchus pani'' |2={{clade |1={{extinct}}''Toyotamaphimeia machikanensis'' |2={{extinct}}''Hanyusuchus sinensis'' }}}} |2={{clade |1={{clade |1={{extinct}}''Eosuchus lerichei'' |2={{extinct}}''Eosuchus minor'' }} |2={{clade |1={{extinct}}''Ocepesuchus eoafricanus'' |2={{clade |1={{extinct}}''Eothoracosaurus mississippiensis'' |2={{clade |1={{extinct}}''Thoracosaurus macrorhynchus'' |2={{extinct}}''Thoracosaurus neocesariensis'' }}}} |3={{clade |1={{extinct}}''Aktiogavialis puertoricensis'' |2={{extinct}}''Eogavialis africanum'' |3={{clade |1={{extinct}}''Argochampsa krebsi'' |2={{clade |1={{extinct}}''Piscogavialis jugaliperforatus'' |2={{clade |1={{extinct}}''Ikanogavialis gameroi'' |2={{clade |1={{extinct}}''Siquisiquesuchus venezuelensis'' |2={{clade |1={{extinct}}''Dadagavialis gunai'' |2={{clade |1={{extinct}}''Gryposuchus neogaeus'' |2={{extinct}}''Gryposuchus croizati'' |3={{clade |1={{extinct}}''Aktiogavialis caribesi'' |2={{extinct}}''Gryposuchus pachakamue'' }}}} |3={{clade |1={{extinct}}''Gryposuchus colombianus'' |2={{extinct}}''Rhamphosuchus crassidens'' |3={{extinct}}Myanmar gavialid |4={{extinct}}''Gavialis lewisi'' |5={{extinct}}''Gavialis bengawanicus'' |6={{clade |1=''Gavialis gangeticus'', '''gharial''' |2={{extinct}}Siwalik ''Gavialis'' }}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}

===Species list=== {{See also|List of crocodilians}} Family '''Gavialidae''' *Subfamily Tomistominae **Genus {{extinct}}''Gavialosuchus''? **Genus {{extinct}}''Maomingosuchus''? **Genus {{extinct}}''Melitosaurus'' **Genus {{extinct}}''Paratomistoma''? **Genus {{extinct}}''Thecachampsa''? **Genus ''Tomistoma'' ***''Tomistoma schlegelii'', false gharial or Malayan gharial ***{{extinct}}''Tomistoma lusitanicum'' *Subfamily Gavialinae **Genus {{extinct}}''Aktiogavialis'' **Genus {{extinct}}''Argochampsa''? **Genus {{extinct}}''Dadagavialis'' **Genus {{extinct}}''Eogavialis''? **Genus {{extinct}}''Eosuchus''? **Genus {{extinct}}''Eothoracosaurus''? **Genus ''Gavialis'' ***''Gavialis gangeticus'', gharial ***{{extinct}}''Gavialis bengawanicus'' **Genus {{extinct}}''Gavialosuchus''? **Genus {{extinct}}''Gryposuchus''? (may by paraphyletic, along with Gryposuchinae)<ref name="LeeYates2018"/> **Genus {{extinct}}''Hanyusuchus'' **Genus {{extinct}}''Harpacochampsa''? **Genus {{extinct}}''Hesperogavialis'' **Genus {{extinct}}''Ikanogavialis'' **Genus {{extinct}}''Maomingosuchus''? **Genus {{extinct}}''Ocepesuchus'' **Genus {{extinct}}''Paratomistoma''? **Genus {{extinct}}''Penghusuchus'' **Genus {{extinct}}''Piscogavialis'' **Genus {{extinct}}''Rhamphosuchus'' **Genus {{extinct}}''Siquisiquesuchus'' **Genus {{extinct}}''Thoracosaurus''? **Genus {{extinct}}''Toyotamaphimeia''

<small>† Indicates extinct group</small>

===Extant species=== {| class="wikitable" |- ! Image !! Scientific name !! Common name !! Distribution |- |150px || ''Gavialis gangeticus'' ||Gharial|| India |- |150px || ''Tomistoma schlegelii''||False gharial, Malayan gharial, Sunda gharial and tomistoma || Peninsular Malaysia, Borneo, Sumatra, and Java. |- |}

==References== {{Commons category}} {{Wikispecies}} {{Reflist}}

{{Crocodilia|G.}} {{Extinct Crocodilia|G.}} {{Crocs}} {{Taxonbar|from=Q878388}} {{Authority control}}

Category:Gavialidae Category:Crocodilian families Category:Taxa named by Andrew Leith Adams Category:Extant Eocene first appearances