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The false gharial (''Tomistoma schlegelii''), also known by the names Malayan gharial, Sunda gharial and tomistoma is a freshwater
crocodilian Crocodilia (or Crocodylia, both ) is an Order (biology), order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous Period (geology), period (Cenomanian St ...
of the family
Gavialidae 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. ...
native to Peninsular Malaysia,
Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and ea ...
, Sumatra and Java. It is listed as Vulnerable on the IUCN Red List, as the global population is estimated at around 2,500 to 10,000 mature individuals. The specific name ''schlegelii'' honors Hermann Schlegel.


Taxonomy

The scientific name ''Crocodilus (Gavialis) schlegelii'' was proposed by
Salomon Müller Salomon Müller (7 April 1804 – 29 December 1864) was a German naturalist. He was born in Heidelberg, and died in Freiburg im Breisgau. Müller was the son of a saddler in Heidelberg. Along with Heinrich Boie and Heinrich Christian Macklot, h ...
in 1838 who described a specimen collected in Borneo. In 1846, he proposed to use the name ''Tomistoma schlegelii'', if it needs to be placed in a distinct genus. The 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 well ...
'' potentially also contains several extinct species like ''T. cairense'', ''T. lusitanicum'', ''T. taiwanicus'', and ''T. coppensi''. However, these species may need to be reclassified to different genera as are paraphyletic. The false gharial's snout broadens considerably towards the base and so is more similar to those of true
crocodiles Crocodiles (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 include all extant taxo ...
than to the gharial (''Gavialis gangeticus''), whose osteology indicated a distinct lineage from all other living crocodilians. However, although more morphologically similar to
Crocodylidae Crocodiles (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 include all extant mem ...
based on skeletal features, recent molecular studies using DNA sequencing consistently indicate that the false gharial 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 fres ...
actually belong to Gavialoidea and Gavialidae. Fossils of extinct ''Tomistoma'' species have been found in deposits of Paleogene, Neogene, and Quaternary ages in Taiwan, Uganda, Italy, Portugal, Egypt and India, but nearly all of them are likely to be distinct genera due to older age compared to the false gharial. 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 ...
of the major living crocodile groups is based on molecular studies and shows the false gharial's close relationships: The following cladogram shows the false gharial's placement within the Gavialidae; it is based on a tip dating study, for which morphological, DNA sequencing 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: lithostra ...
data were analysed:


Characteristics

The false gharial is dark reddish-brown above with dark brown or black spots and cross-bands on the back and tail.
Ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
s are grayish-white, with some lateral dark mottling. Juveniles are mottled with black on the sides of the jaws, body, and tail. The smooth and unornamented snout is extremely long and slender, parallel sided, with a length of 3.0 to 3.5 times the width at the base. All teeth are long and needle-like, interlocking on the insides of the jaws, and are individually socketed. The dorsal scales are broad at midbody and extend onto the sides of the body. The digits are webbed at the base. Integumentary sensory organs are present on the head and body
scalation In most biological nomenclature, a scale ( grc, λεπίς, lepís; la, squāma) is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran (butterfly and moth) species, scales are plates on the surf ...
. Scales behind the head are frequently a slightly enlarged single pair. Some individuals bear a number of adjoining small keeled scales. Scalation is divided medially by soft granular skin. Three transverse rows of two enlarged
nuchal The nape is the back of the neck. In technical anatomical/medical terminology, the nape is also called the nucha (from the Medieval Latin rendering of the Arabic , "spinal marrow"). The corresponding adjective is ''nuchal'', as in the term ''n ...
scales are continuous with the
dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...
scales, which consist of 22 transverse rows of six to eight scales, are broad at midbody and extend onto the sides of the body. Nuchal and dorsal rows equals a total of 22 to 23 rows. It has 18 double-crested
caudal Caudal may refer to: Anatomy * Caudal (anatomical term) (from Latin ''cauda''; tail), used to describe how close something is to the trailing end of an organism * Caudal artery, the portion of the dorsal aorta of a vertebrate that passes into the ...
whorls and 17 single-crested caudal whorls. The flanks have one or two longitudinal rows of six to eight very enlarged scales on each side.Brazaitis, P. (2001) ''A Guide to the Identification of the Living Species of Crocodilians''. Science Resource Center, Wildlife Conservation Society The false gharial has one of the slimmest snouts of any living crocodilian, comparable to that of the
slender-snouted crocodile ''Mecistops'' is a genus of crocodiles, the slender-snouted crocodiles, native to sub-Saharan Africa. Taxonomy and etymology Traditionally placed in '' Crocodylus'', recent studies in DNA and morphology have shown that it is in fact basal to ...
and the freshwater crocodile in slenderness; only that of the gharial is noticeably slimmer. Males can reportedly grow up to in length. Three mature males kept in captivity measured and weighed , while a female measured and weighed . Females have been recorded at lengths of up to . The false gharial apparently has the largest skull of any extant crocodilian, in part because of the great length of the slender snout. Out of the eight longest crocodilian skulls from existing species that could be found in museums around the world, six of these belonged to false gharials. The longest crocodilian skull belonging to an extant species was of this species and measured in length, with a mandibular length of . Most of the owners of these enormous skulls had no confirmed (or even anecdotal) total measurements for the animals, but based on the known skull-to-total length ratio for the species they would measure approximately in length. The false gharial is considered to be a large crocodilian, with one large male individual weighing . Three individuals ranging from in length and weighing from had a
bite force Bite force quotient (BFQ) is a numerical value commonly used to represent the bite force of an animal, while also taking factors like the animal's size into account. The BFQ is calculated as the regression of the quotient of an animal's bite f ...
of .


Distribution and habitat

False gharials are native to Peninsular Malaysia,
Sarawak Sarawak (; ) is a state of Malaysia. The largest among the 13 states, with an area almost equal to that of Peninsular Malaysia, Sarawak is located in northwest Borneo Island, and is bordered by the Malaysian state of Sabah to the northeast, K ...
, and Indonesia ( Sumatra, and
Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and ea ...
), but were extirpated in Singapore, Vietnam, and Thailand. It is unclear if they remain in Java. Apart from rivers, they inhabit swamps and lakes. The species is almost entirely found today in peat swamps and lowland swamp forests. In the 1990s, information and sightings were available from 39 localities in 10 different river drainages, along with the remote river systems of Borneo. Prior to the 1950s, ''Tomistoma'' occurred in freshwater ecosystems along the entire length of Sumatra east of the
Barisan Mountains The Bukit Barisan or the Barisan Mountains are a mountain range on the western side of Sumatra, Indonesia, covering nearly 1,700 km (1,050 mi) from the north to the south of the island. The Bukit Barisan range consists primarily of volca ...
. The current distribution in eastern Sumatra has been reduced by 30-40% due to hunting, logging, fires, and agriculture.Bezuijen, M.R., Webb, G.J.W., Hartoyo, P., Samedi, Ramono, W.S., Manolis, S.C. (1998) "The False Gharial (''Tomistoma schlegelii'') in Sumatra". In: ''Crocodiles. Proceedings of the 14th Working Meeting of the Crocodile Specialist Group'', IUCN. The World Conservation Union, Gland, Switzerland and Cambridge, UK. Pp. 10–31.


Ecology and behaviour


Diet

Until recently, very little was known about the diet or behaviour of the false gharial in the wild. Details are slowly being revealed. In the past, the false gharial was thought to have a diet of only fish and very small vertebrates, but more recent evidence indicates that it has a generalist diet despite its narrow snout. In addition to fish and smaller aquatic animals, mature adults prey on larger vertebrates, including proboscis monkeys,
long-tailed macaque The crab-eating macaque (''Macaca fascicularis''), also known as the long-tailed macaque and referred to as the cynomolgus monkey in laboratories, is a cercopithecine primate native to Southeast Asia. A species of macaque, the crab-eating macaqu ...
s, deer, water birds, and reptiles. There is an eyewitness account of a false gharial attacking a
cow Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ma ...
in East Kalimantan. The false gharial may be considered an ecological equivalent to Neotropical crocodiles such as the
Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wo ...
and
American crocodile The American crocodile (''Crocodylus acutus'') is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas, with populations present from South Florida and the coas ...
s, which both have slender snouts but a broad diet.


Reproduction

False gharials are mound-nesters. Females lay small clutches of 13 to 35 eggs per nest, and appear to produce the largest eggs of extant crocodilians. Sexual maturity in females appears to be attained around , which is large compared to other crocodilians. It is not known when they breed in the wild or when the nesting season is. Once the eggs are laid, and construction of the mound is completed, the female abandons her nest. Unlike most other crocodilians, the young receive no parental care and are at risk of being eaten by predators, such as
mongoose A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family is currently split into two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to s ...
s, tigers,
leopard The leopard (''Panthera pardus'') is one of the five extant species in the genus ''Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, a ...
s, and
wild dogs Wild Dogs is an American heavy metal band from Portland, Oregon, formed loosely in 1981 by original members Jeff Mark, Danny Kurth, Matt McCourt, and Pete Holmes. The band has since released six albums, three live albums and one DVD. Wild Dogs ...
. The young hatch after 90 days and are left to fend for themselves.


Conflict

In 2008, a 4-m female false gharial attacked and ate a fisherman in central Kalimantan; his remains were found in the gharial's stomach. This was the first verified fatal human attack by a false gharial. However, by 2012, at least two more verified fatal attacks on humans by false gharials had occurred indicating perhaps an increase of human-false gharial conflict possibly correlated to the decline of habitat, habitat quality, and natural prey numbers.


Threats

The false gharial is threatened with extinction throughout most of its range due to the
drainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging (anaerobic condition ...
of its freshwater swamplands and clearance of surrounding rainforests. The species is also hunted frequently for its skin and meat, and the eggs are often harvested for human consumption.


Conservation

The false gharial is listed on
CITES Appendix I CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
. Currently population surveys indicate that while the false gharial is not for the most extirpated from areas it used to inhabit, the distribution of individuals is much more spotty than the previously more connective distribution, putting the animals at risk of genetic isolation. In large part, the isolation of false gharials is due to extremely extensive habitat destruction and disturbance within the species' area of distribution, few areas outside of legally protected areas are likely to bear viable breeding populations. Steps have been taken by the Malaysian and Indonesian governments to prevent its extinction in the wild. There are reports of some populations rebounding in Indonesia, yet with this slight recovery, mostly irrational fears of attacks have surfaced amongst the local human population. Yayasan Ulin (The Ironwood Foundation) is currently attempting to manage a wetland area in East Kalimantan, which is known to contain the false gharials.


References


External links

* Crocodile Specialist Group:  
''Tomistoma'' Task Force

Saint Louis Zoo: False gharial

ARKive
Images
BBC News: 'Match-making' for rare male croc

The Orangutan Foundation research centre being used for critical research on false gharials
{{Taxonbar, from=Q242464 Gavialidae Reptiles of Malaysia Reptiles of Indonesia Reptiles of Borneo Reptiles described in 1838 Apex predators Crocodilians of Asia