Big-headed Amazon River turtle

Last updated

Peltocephalus dumerilianus
Peltocephalus dumerilianus photo.jpg
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Pleurodira
Family: Podocnemididae
Subfamily: Erymnochelyinae
Genus: Peltocephalus
A.M.C. Duméril & Bibron, 1835  [3]
Species:
P. dumerilianus
Binomial name
Peltocephalus dumerilianus
(Schweigger, 1812)  [4]
Peltocephalus dumerilianus range.jpg
Range
Synonyms [1] [5]
List
  • Emys dumeriliana
    Schweigger, 1812
  • Emys macrocephala
    Spix, 1824
  • Emys tracaxa
    Spix, 1824
  • Chelys (Hydraspis) lata
    Gray in Griffith, 1831
  • Emys icterocephala
    Gray in Griffith, 1831
  • Chelys (Hydraspis)
    dumerilliana
    [sic]
    — Gray, 1831
  • Podocnemis dumeriliana
    A.M.C. Duméril & Bibron, 1835
  • Peltocephalus tracaxa
    — A.M.C. Duméril & Bibron, 1835
  • Podocnemis tracaxa
    Boulenger, 1889
  • Peltocephalus dumeriliana
    Obst, 1985
  • Peltocephalus dumerilianus
    Gorzula & Señaris, 1999

The Big-headed Amazon River turtle (Peltocephalus dumerilianus), [5] also known as the big-headed sideneck, is a species of turtle in the family Podocnemididae. [3]

Contents

Taxonomy

By a lake on the Tapajos River. Peltocephalus dumerilianus Tapajos.jpg
By a lake on the Tapajós River.

An additional, much larger species of Peltocephalus is known, the extinct Peltocephalus maturin . [6]

Peltocephalus is the most basal podocnemidid genus, splitting off in the Cretaceous around 86 million years ago. [7]

Etymology

The specific name, dumerilianus, is in honor of French herpetologist André Marie Constant Duméril. [8]

Description

Tails of a female (A) and male (B) Peltocephalus dumerilianus female and male tails.jpg
Tails of a female (A) and male (B)

The largest specimen recorded possessed a 50 cm (1.6 ft) long carapace and weighing 15 kg (33 lb). However, Alfred Russel Wallace recorded coming across a remarkably large Peltocephalus specimen that eight people fed on with enough for leftovers for the next day. The exact size of this specimen is unknown. [7]

Sexual dimorphism is present like in most turtles, with males being larger with wider heads and longer tails. [7]

It is considered morphologically similar to another podocnemidid, the Madagascan big-headed turtle, which is similarly omnivorous unlike the herbivorous genus Podocnemis . [7] [9]

Geographic range

P. dumerilianus is found in Brazil (Amazonas, Pará), Colombia, French Guiana, Venezuela, Ecuador, and possibly in Peru. [5]

Habitat

The preferred natural habitats of P. dumerilianus are rivers and freshwater swamps, preferring igapó and other blackwater river systems. [5] [10]

Behaviour

1824 illustration Peltocephalus dumerilianus.jpg
1824 illustration

While not territorial, its strong jaws have been recorded severely injuring a child's knee, and ribeirinhos often report them mutilating the fingers of adults. Even juveniles have bites powerful enough to tear chunks off a conspecific's plastron. Captive specimens can be highly aggressive towards other turtle species, even killing them. [7]

Less agile swimmers than other podocnemidid turtles, they are generally thought to not disperse across long distances; one 19-year-old male was captured in the same stream where he was first tagged as a hatchling. [7]

Diet

Like all extant podocnemidids, P. dumerilianus is a plant-based omnivore, though includes the largest proportion of animal matter in its diet among its family. Nevertheless, fruits and seeds can represent up to 85% of its diet. It has a preference for apple snails when available. [11] As undigested seeds have been observed in the intestines, it may be an important seed disperser. [7] It is an opportunistic predator, usually crawling around the bottom of water bodies searching for mollusks, fish, insects, and even scavenged carrion from other reptiles and mammals. [12]

Adults have been observed sitting immobile underwater with their jaws open, possibly trying to catch prey with a sit-and-wait approach also seen in alligator snapping turtles. [7]

Reproduction

Like all other turtles, P. dumerilianus is oviparous. [5] Unlike other members of its group which lay their eggs on sandy beaches, the Big-headed Amazon River turtle prefers concealed nests. [7]

Conservation

Although listed as Vulnerable by the IUCN, the assessment was made in 1996. This may no longer be reflective of the level of threat against this species, as there has been habitat degradation through river contamination by mining activities and pesticides, deforestation, and the construction of hydroelectricity infrastructure. Additionally, illegal gold mining evicts over 1000 of the turtles per year (although this may be an underestimate), and may then be sold on the market at a price of up to USD $50 per turtle. [7]

The species is hunted for consumption in its range. During Alfred Russel Wallace's expedition along the Negro and Orinoco rivers, he and his team often fed on it. He records that while indigenous people in the upper Rio Negro often hunted the species, and penned them when there was scarcity of food, they also told him that the species was getting rarer. [7]

Related Research Articles

<span class="mw-page-title-main">Pelomedusidae</span> Family of turtles

Pelomedusidae is a family of freshwater turtles endemic to sub-Saharan Africa, including Madagascar, São Tomé, and the Seychelles. They range in size from 12 to 45 cm in carapace length, and are generally roundish in shape. They are unable to fully withdraw their heads into their shells, instead drawing them to the side and folding them beneath the upper edge of their shells, hence are called African side-necked turtles.

<span class="mw-page-title-main">Podocnemididae</span> Family of turtles

Podocnemididae is a family of pleurodire (side-necked) turtles, once widely distributed. Most of its 41 genera and 57 species are now extinct. Seven of its eight surviving species are native to South America: the genus Peltocephalus, with two species, only one of which is extant ; and the genus Podocnemis, with six living species of South American side-necked river turtles and four extinct. There is also one genus native to Madagascar: Erymnochelys, the Madagascan big-headed turtle, whose single species E. madagascariensis.

<span class="mw-page-title-main">Arrau turtle</span> Species of turtle

The Arrau turtle, also known as the South American river turtle, giant South American turtle, giant Amazon River turtle, Arrau sideneck turtle, Amazon River turtle or simply the Arrau, is the largest of the side-neck turtles (Pleurodira) and the largest freshwater turtle in Latin America. The species primarily feeds on plant material and typically nests in large groups on beaches. Due to hunting of adults, collecting of their eggs, pollution, habitat loss, and dams, the Arrau turtle is seriously threatened.

<i>Podocnemis</i> Genus of turtles

Podocnemis is a genus of aquatic turtles, commonly known as South American river turtles, in the family Podocnemididae. The genus consists of six extant species occurring in tropical South America. Four additional species are known only from fossils. These turtles have pig-like noses but are not closely related to the pig-nosed turtle.

<span class="mw-page-title-main">Yellow-spotted river turtle</span> Species of turtle

The yellow-spotted Amazon river turtle, also known commonly as the yellow-headed sideneck turtle and the yellow-spotted river turtle, and locally as the taricaya, is one of the largest South American river turtles.

<i>Stupendemys</i> Extinct genus of turtles

Stupendemys is an extinct genus of freshwater side-necked turtle, belonging to the family Podocnemididae. It is the largest freshwater turtle known to have existed, with a carapace over 2 meters long. Its fossils have been found in northern South America, in rocks dating from the Middle Miocene to the very start of the Pliocene, about 13 to 5 million years ago. Male specimens are known to have possessed bony horns growing from the front edges of the shell and the discovery of the fossil of a young adult shows that the carapace of these turtles flattens with age. A fossil skull described in 2021 indicates that Stupendemys was a generalist feeder.

<span class="mw-page-title-main">Madagascan big-headed turtle</span> Species of turtle

The Madagascan big-headed turtle is a turtle native to the waters of permanent slow moving rivers and lakes in western Madagascar. These turtles are critically endangered and have been evaluated to be the most endangered turtle in the world by a 2018 review. Due to its ancient origins and threatened status, it is ranked as #1 on the EDGE of Existence programme's list of priority reptiles.

<span class="mw-page-title-main">Red-headed Amazon River turtle</span> Species of turtle

The red-headed Amazon side-necked turtle, red-headed river turtle or red-headed sideneck is a species of turtle in the family Podocnemididae. It is found in the Amazon basin in Brazil, Colombia, and Venezuela. The red-headed river turtle is considered a small turtle with a size of less than 32 cm, making it easily distinguishable from other species in the area. Identifying factors of this turtle include colors ranging from dark brown to black, barbels under the chin, and a bright red strip that goes from behind its head to the tympanum.

<span class="mw-page-title-main">Magdalena River turtle</span> Species of turtle

The Magdalena River turtle or Rio Magdalena river turtle is a species of turtle in the family Podocnemididae, which diverged from other turtles in the Cretaceous Period, 100 million years ago. It is endemic to northern Colombia, where its home range consists of the Sinú, San Jorge, Cauca, and Magdalena river basins.

River turtle may refer to:

<span class="mw-page-title-main">August Friedrich Schweigger</span> German naturalist (1783–1821)

August Friedrich Schweigger was a German naturalist born in Erlangen. He was the younger brother of scientist Johann Salomo Christoph Schweigger (1779-1857).

<i>Mesoclemmys</i> Genus of turtles

Mesoclemmys is a genus of South American turtles in the family Chelidae.

Brontochelys is an extinct genus of podocnemidid from the Miocene of Pakistan. The only species known, B. gaffneyi was classified before in the genus Shweboemys, which is known from the Pliocene of Burma. Brontochelys is represented only by its type specimen BMNH R.8570, a nearly complete skull, which exact locality is unknown but probably comes from the Lower Miocene sediments in the Bugti Hills, in Baluchistan, Pakistan. This skull is different from its relatives like Shweboemys, Lemurchelys and Stereogenys by its large, forward-faced orbits, a large frontal bone that composes most of the dorsal orbit margin and a palatal curved. The name of Brontochelys is formed by the Greek words bronte, "thunder" and chelys, "turtle", in reference to the large size of the skull.

<i>Carbonemys</i> Extinct genus of turtles

Carbonemys cofrinii is an extinct giant podocnemidid turtle known from the Middle Paleocene Cerrejón Formation of the Cesar-Ranchería Basin in northeastern Colombia. The formation is dated at around 60 to 57 million years ago, starting at about five million years after the KT extinction event.

<i>Bauruemys</i> Extinct genus of turtles

Bauruemys is an extinct genus of turtles in the family Podocnemididae.

Bairdemys is an extinct genus of side-necked turtles in the family Podocnemididae. The genus existed from the Late Oligocene to Late Miocene and its fossils have been found in South Carolina, Puerto Rico, Panama and Venezuela. The genus was described in 2002 by Gaffney & Wood and the type species is B. hartsteini.

<i>Caninemys</i> Extinct genus of turtles

Caninemys is an extinct genus of large freshwater side-necked turtle, belonging to the family Podocnemididae. Its fossils have been found in Brazil and Colombia, in rocks dating back from the middle to late Miocene.

<i>Amabilis uchoensis</i> Extinct species of turtles

Amabilis uchoensis is a species of prehistoric pleurodiran turtle from the Late Cretaceous of South America. It is the only species in the genus Amabilis.

<i>Peltocephalus maturin</i> Extinct species of turtle

Peltocephalus maturin is an extinct species of podocnemidid river turtle closely related to the big-headed Amazon River turtle that lived during the Late Pleistocene and Early Holocene in what is now Brazil. P. maturin is known from a singular lower jaw of enormous size, with estimates suggesting its carapace may have reached lengths of around 1.70 m. This would make it one of the largest freshwater turtles in history, comparable in size to the Paleocene podocnemidid Carbonemys and only exceeded by the Miocene podocnemidid Stupendemys. Like its closest relative, it was likely an omnivore, the narrow cutting surface of its lower jaw unsuited for strict herbivory or durophagy.

<i>Neochelys</i>

Neochelys is an extinct genus of freshwater side-necked turtle that inhabited Europe during the Eocene. It was a diverse genus known throughout western and southern Europe from the Ypresian to the Priabonian.

References

  1. 1 2 Tortoise & Freshwater Turtle Specialist Group (1996). "Peltocephalus dumerilianus ". IUCN Red List of Threatened Species . 1996: e.T16511A5972664. doi: 10.2305/IUCN.UK.1996.RLTS.T16511A5972664.en . Retrieved 11 January 2018.
  2. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. 1 2 "Peltocephalus ". Integrated Taxonomic Information System.
  4. "Peltocephalus dumerilianus ". Integrated Taxonomic Information System.
  5. 1 2 3 4 5 "Peltocephalus dumerilianus ". The Reptile Database.
  6. Ferreira, G. S.; Nasciemento, E. R.; Cadena, E. A.; Cozzuol, M. A.; Farina, B. M.; Pacheco, M. L. A. F.; Rizzutto, M. A.; Langer, M. C. (2024). "The latest freshwater giants: a new Peltocephalus (Pleurodira: Podocnemididae) turtle from the Late Pleistocene of the Brazilian Amazon". Biology Letters. 20 (3). 20240010. doi:10.1098/rsbl.2024.0010. PMC   10932709 . PMID   38471564.
  7. 1 2 3 4 5 6 7 8 9 10 11 Gentil, Eduardo; de Medeiros, Larissa Azevedo; Vogt, Richard Carl; Barnett, Adrian Ashton (2021-10-20). "Biology of the Big-headed Amazon River Turtle, Peltocephalus dumerilianus (Schweigger, 1812) (Testudines, Pleurodira): the basal extant Podocnemididae species". Herpetozoa. 34: 207–222. doi: 10.3897/herpetozoa.34.e67807 . ISSN   2682-955X.
  8. Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN   978-1-4214-0135-5. (Peltocephalus dumeriliana, p. 77).
  9. Eisemberg, Carla C.; Reynolds, Stephen J.; Christian, Keith A.; Vogt, Richard C. (2017-02-01). "Diet of Amazon river turtles (Podocnemididae): a review of the effects of body size, phylogeny, season and habitat". Zoology. 120: 92–100. Bibcode:2017Zool..120...92E. doi:10.1016/j.zool.2016.07.003. ISSN   0944-2006. PMID   27552858.
  10. Gentil, E.; Azevedo de Medeiros, L.; Vogt, R. C.; Barnett, A. A. (2021). "Biology of the Big-headed Amazon River Turtle, Peltocephalus dumerilianus (Schweigger, 1812) (Testudines, Pleurodira): the basal extant Podocnemididae species". Herpetozoa. 34: 207–222. doi: 10.3897/herpetozoa.34.e67807 .
  11. Eisemberg, C. C.; Reynolds, S. J.; Christian, K. A.; Vogt, R. C. (2017). "Diet of Amazon river turtles (Podocnemididae): a review of the effects of body size, phylogeny, season and habitat". Zoology. 120: 92–100. Bibcode:2017Zool..120...92E. doi:10.1016/j.zool.2016.07.003. PMID   27552858.
  12. Gentil, E.; Azevedo de Medeiros, L.; Vogt, R. C.; Barnett, A. A. (2021). "Biology of the Big-headed Amazon River Turtle, Peltocephalus dumerilianus (Schweigger, 1812) (Testudines, Pleurodira): the basal extant Podocnemididae species". Herpetozoa. 34: 207–222. doi: 10.3897/herpetozoa.34.e67807 .

Further reading