Gavialidae is a
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
of large
semiaquatic
In biology, semiaquatic can refer to various types of animals that spend part of their time in water, or plants that naturally grow partially submerged in water. Examples are given below.
Semiaquatic animals
Semiaquatic animals include:
* Verte ...
crocodilia
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...
ns with elongated, narrow snouts. Gavialidae consists of two
living
Living or The Living may refer to:
Common meanings
*Life, a condition that distinguishes organisms from inorganic objects and dead organisms
** Living species, one that is not extinct
*Personal life, the course of an individual human's life
* ...
species, the
gharial
The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males have a distinct b ...
(''Gavialis gangeticus'') and the
false gharial
The false gharial (''Tomistoma schlegelii''), also known by the names Malayan gharial, Sunda gharial and tomistoma is a freshwater crocodilian of the family Gavialidae native to Peninsular Malaysia, Borneo, Sumatra and Java. It is listed as Vu ...
(''Tomistoma schlegelii''), both occurring in Asia. Many
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
members are known from a broader range, including the recently extinct ''
Hanyusuchus
''Hanyusuchus'' is an extinct genus of gavialid crocodilian from the Holocene of South China. It contains a single species, ''Hanyusuchus sinensis''. Reaching a total body length of , it shares characteristics of both Tomistominae, tomistomines a ...
''. Gavialids are generally regarded as lacking the jaw strength to capture the large mammalian prey favoured by crocodiles and
alligator
An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additiona ...
s of similar size so their thin snout is best used to catch fish, however the false gharial has been found to have a
generalist
A generalist is a person with a wide array of knowledge on a variety of subjects, useful or not. It may also refer to:
Occupations
* a physician who provides general health care, as opposed to a medical specialist; see also:
** General pract ...
diet with mature adults preying upon larger vertebrates, such as
ungulates
Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...
.
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. It is currently recognized as a
crown group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
,
meaning that it only includes the
last common ancestor
In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...
of all
extant
Extant is the opposite of the word extinct. It may refer to:
* Extant hereditary titles
* Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English
* Extant taxon, a taxon which is not extinct, ...
(living) gavialids (the
gharial
The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males have a distinct b ...
and
false gharial
The false gharial (''Tomistoma schlegelii''), also known by the names Malayan gharial, Sunda gharial and tomistoma is a freshwater crocodilian of the family Gavialidae native to Peninsular Malaysia, Borneo, Sumatra and Java. It is listed as Vu ...
) and their descendants (living or
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
).
Traditionally, crocodiles and alligators were considered more closely related and grouped together in the clade
Brevirostres
Brevirostres is a paraphyletic group of crocodilians that included alligatoroids and crocodyloids. Brevirostres are crocodilians with small snouts, and are distinguished from the long-snouted gharials. It is defined phylogenetically as the last ...
, 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.
However, recent molecular studies using
DNA sequencing
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
have rejected Brevirostres upon finding the crocodiles and gavialids to be more closely related than the alligators.
The new clade
Longirostres
Longirostres is a clade of crocodilians that includes the crocodiles and the gavialids, to the exclusion of the alligatoroids. Named in 2003 by Harshman ''et al.'', Longirostres is a crown group defined phylogenetically as including the last c ...
was named by Harshman ''et al.'' in 2003.
In addition, these recent molecular DNA studies consistently indicate that the
false gharial
The false gharial (''Tomistoma schlegelii''), also known by the names Malayan gharial, Sunda gharial and tomistoma is a freshwater crocodilian of the family Gavialidae native to Peninsular Malaysia, Borneo, Sumatra and Java. It is listed as Vu ...
(''Tomistoma'') (and by inference other related extinct forms) traditionally viewed as belonging to the crocodylian subfamily
Tomistominae
Tomistominae is a subfamily of crocodylians that includes one living species, the false gharial. Many more extinct species are known, extending the range of the subfamily back to the Eocene epoch. In contrast to the false gharial, which is a fre ...
actually belong to
Gavialoidea
Gavialoidea is one of three superfamilies of crocodylians, the other two being Alligatoroidea and Crocodyloidea. Although many extinct species are known, only the gharial ''Gavialis gangeticus'' and the false gharial ''Tomistoma schlegelii'' are ...
(and Gavialidae).
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
Crocodyloidea is one of three superfamilies of crocodilians, the other two being Alligatoroidea and Gavialoidea, and it includes the crocodiles. Crocodyloidea may also include the extinct Mekosuchinae, native to Australasia from the Eocene to th ...
as close relatives of crocodile
Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...
s, based solely on morphological evidence.
A 2018 tip dating Tip dating is a technique used in molecular dating that allows the inference of time-calibrated phylogenetic trees. Its defining feature is that it uses the ages of the samples to provide time information for the analysis, in contrast with traditio ...
study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
), and stratigraphic
Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks.
Stratigraphy has three related subfields: lithostrati ...
(fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
age) data established the inter-relationships within Crocodilia
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...
, which was expanded upon in 2021 by Hekkala ''et al.'' using paleogenomics Paleogenomics is a field of science based on the reconstruction and analysis of genomic information in extinct species. Improved methods for the extraction of ancient DNA (aDNA) from museum artifacts, ice cores, archeological or paleontological site ...
by extracting DNA from the extinct ''Voay
''Voay'' is an extinct genus of crocodile from Madagascar that lived during the Late Pleistocene to Holocene, containing only one species, ''V. robustus''. Numerous subfossils have been found, including complete skulls, noted for their distinctiv ...
''. 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
Homoplasy, in biology and phylogenetics, is the term used to describe a Phenotypic trait, feature that has been gained or lost independently in separate lineages over the course of evolution. This is different from Homology (biology), homology, wh ...
convergence
Convergence may refer to:
Arts and media Literature
*''Convergence'' (book series), edited by Ruth Nanda Anshen
* "Convergence" (comics), two separate story lines published by DC Comics:
**A four-part crossover storyline that united the four Wei ...
between thoracosaurs and ''Gavialis''.
The below cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
from latest study shows Gavialidae's placement within Crocodylia
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...
:
Here is a more detailed cladogram that shows the proposed phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
of Gavialidae including extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
members:
Species list
Family Gavialidae
*Subfamily Tomistominae
Tomistominae is a subfamily of crocodylians that includes one living species, the false gharial. Many more extinct species are known, extending the range of the subfamily back to the Eocene epoch. In contrast to the false gharial, which is a fre ...
**Genus ''Gavialosuchus
''Gavialosuchus'' is an extinct genus of gavialid crocodylian from the early Miocene of Europe. Currently only one species is recognized, as a few other species of ''Gavialosuchus'' have since been reclassified to other genera.
Taxonomy
The typ ...
''?
**Genus ''Maomingosuchus
''Maomingosuchus'' is an extinct genus of gavialoid crocodylian from Late Eocene of Southeast Asia. It was discovered in Priabonian-aged deposits of China and possibly also Thailand. The type species, originally ''Tomistoma petrolica,'' was named ...
''?
**Genus '' Melitosaurus''
**Genus ''Paratomistoma
''Paratomistoma'' (meaning "next to or near ''Tomistoma''") is an extinct monospecific genus of gavialoid crocodylian. It is based on the holotype specimen CGM 42188, a partial posterior skull and lower jaw discovered at Wadi Hitan, Egypt ...
''?
**Genus ''Thecachampsa
''Thecachampsa'' is an extinct genus of gavialoid crocodylian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found from the eastern United States in deposits of Miocene age. Those named in the 19th century we ...
''?
**Genus ''Tomistoma
''Tomistoma'' is a genus of gavialid crocodilians. They are noted for their long narrow snouts used to catch fish, similar to the gharial. ''Tomistoma'' contains one extant (living) member, the false gharial (''Tomistoma schlegelii''), as we ...
''
***''Tomistoma schlegelii'', false gharial
The false gharial (''Tomistoma schlegelii''), also known by the names Malayan gharial, Sunda gharial and tomistoma is a freshwater crocodilian of the family Gavialidae native to Peninsular Malaysia, Borneo, Sumatra and Java. It is listed as Vu ...
or Malayan gharial
***''Tomistoma lusitanica
''Tomistoma'' is a genus of gavialid crocodilians. They are noted for their long narrow snouts used to catch fish, similar to the gharial. ''Tomistoma'' contains one extant (living) member, the false gharial (''Tomistoma schlegelii''), as we ...
''
*Subfamily Gavialinae
Gavialinae is a subfamily of large semiaquatic crocodilian reptiles, resembling crocodiles, but with much thinner snouts. Gavialinae is one of the two major subfamilies within the family Gavialidae - the other being the subfamily Tomistominae, ...
**Genus '' Aktiogavialis''
**Genus ''Argochampsa
''Argochampsa'' (meaning " Argo crocodile", in reference to the mythological ''Argo'' of Jason) is an extinct genus of eusuchian crocodylomorph, usually regarded as a gavialoid crocodilian, related to modern gharials. It lived in the Paleoce ...
''?
**Genus '' Dadagavialis''
**Genus '' Eogavialis''?
**Genus ''Eosuchus
''Eosuchus'' ("dawn crocodile") is an extinct genus of eusuchian Crocodylomorpha, crocodylomorph, traditionally regarded as a Gavialoidea, gavialoid crocodilian. It might have been among the most Basal (phylogenetics), basal of all gavialoids, l ...
''?
**Genus ''Eothoracosaurus
''Eothoracosaurus'' is an extinct monospecific genus of eusuchian Crocodylomorpha, crocodylomorphs found in Eastern United States which existed during the Late Cretaceous period. ''Eothoracosaurus'' is considered to belong to an informally named ...
''?
**Genus ''Gavialis
''Gavialis'' is a genus of crocodylians that includes the living gharial ''Gavialis gangeticus'' and one known extinct species, '' Gavialis bengawanicus.'' ''G. gangeticus'' comes from the Indian Subcontinent, while ''G. bengawanicus'' is known ...
''
***''Gavialis gangeticus'', gharial
The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males have a distinct b ...
***'' Gavialis bengawanicus''
**Genus ''Gavialosuchus
''Gavialosuchus'' is an extinct genus of gavialid crocodylian from the early Miocene of Europe. Currently only one species is recognized, as a few other species of ''Gavialosuchus'' have since been reclassified to other genera.
Taxonomy
The typ ...
''?
**Genus ''Gryposuchus
''Gryposuchus'' is an extinct genus of gavialid crocodilian. Fossils have been found from Argentina, Colombia, Venezuela, Brazil and the Peruvian Amazon. The genus existed during the Miocene epoch (Colhuehuapian to Huayquerian). One recently d ...
''? (may by paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
, along with Gryposuchinae
Gryposuchinae is an extinct subfamily (biology), subfamily of Gavialidae, gavialid crocodylians. Gryposuchines lived mainly in the Miocene of South America. However, ''Ikanogavialis, "Ikanogavialis" papuensis'' may have survived more recently, in ...
)
**Genus ''Hanyusuchus
''Hanyusuchus'' is an extinct genus of gavialid crocodilian from the Holocene of South China. It contains a single species, ''Hanyusuchus sinensis''. Reaching a total body length of , it shares characteristics of both Tomistominae, tomistomines a ...
''
**Genus ''Harpacochampsa
''Harpacochampsa'' is a poorly known Early Miocene crocodilian from the Bullock Creek lagerstätte of the Northern Territory, Australia. The current specimen consists of a partial skull and fragments of a long, slender snout reminiscent of that ...
''?
**Genus '' Hesperogavialis''
**Genus ''Ikanogavialis
''Ikanogavialis'' is an extinct genus of gavialid crocodilian. Fossils have been found in the Urumaco Formation in Urumaco, Venezuela and the Solimões Formation of Brazil. The strata from which remains are found are late Miocene in age, rather t ...
''
**Genus ''Maomingosuchus
''Maomingosuchus'' is an extinct genus of gavialoid crocodylian from Late Eocene of Southeast Asia. It was discovered in Priabonian-aged deposits of China and possibly also Thailand. The type species, originally ''Tomistoma petrolica,'' was named ...
''?
**Genus ''Ocepesuchus
''Ocepesuchus'' (meaning "Ocepe crocodile", in reference to the OCP, or Office Chérifien des Phosphates, a phosphate-mining company that participated in the excavation of the specimen) is an extinct genus of gavialoid crocodilian, related to mod ...
''
**Genus ''Paratomistoma
''Paratomistoma'' (meaning "next to or near ''Tomistoma''") is an extinct monospecific genus of gavialoid crocodylian. It is based on the holotype specimen CGM 42188, a partial posterior skull and lower jaw discovered at Wadi Hitan, Egypt ...
''?
**Genus ''Penghusuchus
''Penghusuchus'' is an extinct genus of gavialid crocodylian. It is known from a skeleton found in Upper Miocene rocks of Penghu Island, off Taiwan. It may be related to two other fossil Asian gavialids: '' Maomingosuchus petrolica'' of southe ...
''
**Genus ''Piscogavialis
''Piscogavialis'' is an extinct monospecific genus of gryposuchine gavialid crocodylian. The only species yet known is ''P. jugaliperforatus''. Fossils of ''Piscogavialis'' have been found from the Mio-Pliocene Pisco Formation of the Sacaco Bas ...
''
**Genus ''Rhamphosuchus
''Rhamphosuchus'' ("Beak crocodile") is an extinct genus of gavialid crocodylians. It lived during the Pliocene and its fossils have been found in two regions; the Siwalik Hills of Pakistan and India as well as the Sindh region of Pakistan. Its ...
''
**Genus ''Siquisiquesuchus
''Siquisiquesuchus'' (meaning " Siquisique crocodile" after the town in Lara, Venezuela, near where the first described specimens were found) is an extinct genus of gavialid crocodilian. It is known from cranial remains and a few postcranial bon ...
''
**Genus '' Thoracosaurus''?
**Genus ''Toyotamaphimeia
''Toyotamaphimeia machikanensis'' (Toyotama-hime from Mountain Machikane ( :ja:待兼山)) is an extinct gavialid crocodylian which lived in Japan during the Pleistocene. A specimen recovered in 1964 at Osaka University during the construction of ...
''
† Indicates extinct group
Extant species
References
{{Taxonbar, from=Q878388
Reptile families
Taxa named by Andrew Leith Adams
Extant Eocene first appearances