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Chelus

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Chelus
Temporal range: Miocene–recent[1]
Chelus fimbriatus
Chelus orinocensis
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Pleurodira
Family: Chelidae
Subfamily: Chelinae
Genus: Chelus
Duméril, 1805[2]
Type species
Testudo fimbriata
Schneider 1783

Chelus is a genus of large freshwater turtles found in tropical South America, known as matamatas, mata-matas, or mata matas. Formerly considered to be a monotypic genus,[3] it now consists of two extant species after Chelus orinocensis was identified in 2020 from a genetic analysis.[4]

Evolution

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Fossils of the extinct †C. colombianus have been found in Venezuela, Colombia, and Brazil, including a skull dating to the early Miocene (~ 16 m.y.) of the Castilletes Formation, Cocinetas Basin, in Colombia. The fossil shows that the skull morphology of Chelus has been almost unchanged since the Miocene.[5][6]

The two extant species diverged during the late Miocene approximately 12.7 million years ago, likely as a result of the tectonic forces that divided the Orinoco basin and Amazon basin around 10.5 million years ago.[7]

Species

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There are two extant recognized species in this genus[3][8] and one extinct species:[1]

Description

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Mata matas are large, sedentary turtles with large, triangular, flattened head with many tubercles and flaps of skin, and a "spike" on their long and tubular snouts.[10] Three barbels occur on the chin and four additional filamentous barbels at the upper jaw, which is neither hooked nor notched.[11]

The mata mata's brown or black, oblong carapace can measure up to 45 cm (18 in) at adult age.[12][13] The mata mata's plastron is reduced, narrowed, hingeless, shortened towards the front, and deeply notched at the rear with narrow bridges.[11] The shell may be meant to resemble a piece of bark, camouflaging it from possible predators.[14] The neck is longer[clarification needed] than the vertebra under its carapace and is fringed with small skin flaps along both sides.[11] Hatchlings show a pink to reddish tinge in the underside edge of their carapaces and plastrons that gradually disappear as they grow.[citation needed] Each forefoot has five webbed claws. Males have concave plastrons and longer, thicker tails than females.[11]

Behavior

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The shell of mata matas shell resemble bark, and their heads resemble fallen leaves.[15] As they remain motionless in the water, the skin flaps enable them to blend into the surrounding vegetation until a fish comes close.[15] Mata mata thrust out their heads and open their large mouths as wide as possible, creating a low-pressure vacuum that sucks the prey into their mouth, known as suction feeding.[15] Mata matas snap their mouth shut, the water is slowly expelled, and fish are swallowed whole.[15]

Mata matas are strictly aquatic, but prefer standing in shallow water where their snouts can reach the surface to breathe.[16]

Diet

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Closeup of a mata mata's head

Mata matas are carnivorous, feeding almost exclusively upon aquatic invertebrates (such as worms, mussels, crustaceans and insects)[17][18][19] and fish.[20][21] On rare occasions, they may feed on small birds, amphibians or small mammals that have entered the water.[22][19] When the stomach contents of 20 wild mata matas were examined it consisted exclusively of small fish. The turtles predominantly feed at night in muddy water with limited visibility. However the turtle is well adapted to hunting in these conditions. Mata matas have very fine eyesight with eyes that reflect light, similar to other nocturnal reptiles. In addition, the skin flaps on the neck are also extremely sensitive and help mata matas detect nearby movement.[23]

Mata matas use a specific method of seizing their prey. They will move the prey into shallower areas of water, surround the prey, and wave their front legs to prevent them from escaping. Once surrounded, mata matas will open their mouths and contract their pharynx, causing a rush of water that pushes the prey into their mouth.[24]

In captivity

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On exhibit at the North Carolina Museum of Natural Sciences

Mata matas are readily available in the exotic pet trade and are quite expensive to obtain. Due to their unique appearance, they make interesting display animals. They also grow quite large. However, mata matas are not active hunters, so, like the alligator snapping turtle, they need less space than a large, active species.

As with all aquatic turtles, water quality is one of the keys to keeping this species successfully in captivity. Warm, acidic water is the best type used with a high tannin content that should be maintained all year round. Moderate to heavy filtration is recommended.[25] Author David Fogel considers his captive mata mata turtles to be quite intelligent. For example, he has observed one turtle positioning itself near the spray bar of the aquarium at feeding time so that floating food is pushed beneath the water's surface where the turtle can catch it more easily.[26]

References

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  1. 1 2 "Chelus Duméril 1806". Paleobiology Database. Retrieved 16 April 2024.
  2. ↑ Duméril, A.M.C. 1805. Zoologie Analytique, ou Méthode Naturelle de Classification des Animaux. Paris: Perronneau, 344 pp.
  3. 1 2 Rhodin, Anders G.J.; Inverson, John B.; Roger, Bour; Fritz, Uwe; Georges, Arthur; Shaffer, H. Bradley; van Dijk, Peter Paul; et al. (Turtle Taxonomy Working Group) (2021). Rhodin A. G.J.; Iverson J.B.; van Dijk P.P.; Saumure R.A.; Buhlmann K.A.; Pritchard P.C.H.; Mittermeier R.A. (eds.). "Turtles of the world, 2021 update: Annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status (9th Ed.)". Chelonian Research Monographs. Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. 9 (8 ed.): 1–472. doi:10.3854/crm.8.checklist.atlas.v9.2021. ISBN 978-1-5323-5026-9.{{cite journal}}: CS1 maint: periodical has ISBN (link)
  4. ↑ Sanchez-Vilaga, Marcelo R.; Prichard, Peter C. H.; Paolillo, Alfredo; Linares, Omar J. (January 1995). "Geographic variation in the matamata turtle, Chelus fimbriatus, with observations on its shell morphology and morphometry" (PDF). Chelonian Conservation and Biology. 1: 292–300.
  5. ↑ Cadena, Ea; Jaramillo, Ca (2015). "The first fossil skull of Chelus (Pleurodira: Chelidae, Matamata turtle) from the early Miocene of Colombia". Palaeontologia Electronica. doi:10.26879/545. ISSN 1094-8074.
  6. 1 2 Ferreira, Gabriel S.; Rincón, Ascanio D.; Solórzano, Andrés; Langer, Max C. (April 2016). "Review of the fossil matamata turtles: earliest well-dated record and hypotheses on the origin of their present geographical distribution". The Science of Nature. 103 (3–4). doi:10.1007/s00114-016-1355-2. ISSN 0028-1042.
  7. ↑ Vargas-Ramírez, Mario; Caballero, Susana; Morales-Betancourt, Mónica A.; Lasso, Carlos A.; Amaya, Laura; Martínez, José Gregorio; das Neves Silva Viana, Maria; Vogt, Richard C.; Farias, Izeni Pires; Hrbek, Tomas; Campbell, Patrick D.; Fritz, Uwe (2020). "Genomic analyses reveal two species of the matamata (Testudines: Chelidae: Chelus spp.) and clarify their phylogeography". Molecular Phylogenetics and Evolution. 148: 106823. doi:10.1016/j.ympev.2020.106823.{{cite journal}}: CS1 maint: article number as page number (link)
  8. ↑ Chelus at the Reptarium.cz Reptile Database. Accessed 16 April 2024.
  9. ↑ Wood, Roger Conant (1975). "Two new species of Chelus (Testudines: Pleurodira) from the Late Tertiary of northern South America". Breviora. 435: 1–26.
  10. ↑ Espenshade III, William H (1990), "Matamata, Chelus fimbriatus", Tortuga Gazette, 26 (5): 3–5
  11. 1 2 3 4 Bartlett, Dick (2007), "The Matamata", Reptiles Magazine, 15 (12): 18–20
  12. ↑ (in French) Toutes les tortues du monde by Franck Bonin, Bernard Devaux and Alain Dupré, second edition (1998), editions Delachaux and Niestlé/WWF.
  13. ↑ Matamata, Chelus fimbriatus, California Turtle & Tortoise Club
  14. ↑ Encyclopedia of Animals: Mammals, Birds, Reptiles and Amphibians, Harold G. Cogger, Edwin Gould, Joseph Forshaw
  15. 1 2 3 4 Cogger, Harold; Zweifel, Richard (1992), Reptiles & Amphibians, Sydney, Australia: Weldon Owen, p. 112, ISBN 978-0-8317-2786-4
  16. ↑ Rosenfeld, Arthur (1989), Exotic Pets, New York: Simon & Schuster, pp. 153–155, ISBN 978-0-671-47654-0
  17. ↑ David, Johnathan (22 February 2022). "Mata Mata Turtle: Care Guide & Species Profile". Everything Reptiles.
  18. ↑ "Mata mata turtle, Chelus fimbrata, care sheet". 14 April 2020.
  19. 1 2 Hailey, A. "Chelus fimbriatus (Mata Mata Turtle)" (PDF). UWI St. Augustine. Retrieved 2023-12-16.
  20. ↑ Espenshade III, William H (1990), "Matamata, Chelus fimbriatus", Tortuga Gazette, 26 (5): 3–5
  21. ↑ Cogger, Harold; Zweifel, Richard (1992), Reptiles & Amphibians, Sydney, Australia: Weldon Owen, p. 112, ISBN 978-0-8317-2786-4
  22. ↑ "Matamata - the Animal Facts - Habitat, Appearance, Diet, Behavior".
  23. ↑ Fogel, David (2011). Matamatas: The Natural History, Captive Care and Breeding of Chelus fimbriatus. Turtle and tortoise preservation Group Turtles of the world series.
  24. ↑ Wise1, Formanowicz Jr.2, Brodie Jr.3, Scott C.1, Daniel R.2, Edmund D.3 (September 1989). "Matamata Turtles Ambush but Do Not Herd Prey". Journal of Herpetology. 23 (3): 297–299. doi:10.2307/1564454. JSTOR 1564454.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  25. ↑ Mata mata Care Sheet
  26. ↑ Fogel, David (2011). Matamatas: The Natural History, Captive Care and Breeding of Chelus fimbriatus. Turtle and Tortoise Preservation group's Turtles of the world series.


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