Chelus

Mata mata Temporal range: Pliocene–Recent PreЄ Є O S D C P T J K Pg N
Shanghai Aquarium
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Pleurodira
Family:	Chelidae
Subfamily:	Chelinae
Genus:	Chelus Duméril, 1806
Species:	C. fimbriata
Binomial name
Chelus fimbriata (Schneider, 1783)
Mata mata distribution
Synonyms
Genus Synonymy Chelus Duméril, 1806 Chelys Oppel, 1811 (nomen novum) Chelyda Rafinesque, 1815 (nomen novum) Matamata Merrem, 1820 (nomen novum)   Species Synonymy Testudo terrestris Fermin, 1765 Nomen rejectum Testudo fimbriata Schneider, 1783 Testudo fimbria Gmelin, 1789 nomen novum Testudo matamata Bruguière, 1792 nomen novum Testudo bispinosa Daudin, 1801 nomen novum Emydes matamata Brongniart, 1805 Chelus fimbriata (Schneider, 1783) recombination Testudo rapara Gray, 1831 nomen novum Testudo raparara Gray, 1844 nomen novum Testudo raxarara Gray, 1856 nomen novum Chelys boulengerii Baur, 1890 nomen novum

The mata mata, mata-mata, or matamata (Chelus fimbriata) is a freshwater turtle found in South America, primarily in the Amazon and Orinoco basins. It is the only extant species in the genus Chelus.

The mata mata was described for the first time by French naturalist Pierre Barrère in 1741 as a "large land turtle with spiky and ridged scales" (translation). It was first classified as Testudo fimbriata by German naturalist Johann Gottlob Schneider in 1783. It was renamed 14 different times in two centuries, finally being renamed Chelus fimbriata in 1992.

The mata mata is a large, sedentary turtle with a large, triangular, flattened head characterized with many tubercles and flaps of skin, and a "horn" on its long and tubular snout. Three barbels occur on the chin and four additional filamentous barbels at the upper jaw, which is neither hooked nor notched.

The mata mata's brown or black, oblong carapace can measure up to 45 cm (18 in) at adult age. The full adult weight is 15 kg (33 lb). The mata mata's plastron is reduced, narrowed, hingeless, shortened towards the front, and deeply notched at the rear with narrow bridges. These may be meant to allow the turtle to resemble a piece of bark, camouflaging it from possible predators. The plastron and bridges are cream to yellow or brown.

The head, neck, tail, and limbs are grayish brown on adults. The neck is longer than the vertebra under its carapace and is fringed with small skin flaps along both sides. Hatchlings show a pink to reddish tinge in the underside edge of their carapaces and plastrons that gradually disappear as they grow.

Each fore foot has five webbed claws. Males have concave plastrons and longer, thicker tails than females.

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