| Peltocephalus dumerilianus | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Testudines |
| Suborder: | Pleurodira |
| Family: | Podocnemididae |
| Genus: | Peltocephalus A.M.C. Duméril & Bibron, 1835 [3] |
| Species: | P. dumerilianus |
| Binomial name | |
| Peltocephalus dumerilianus | |
| Synonyms [1] [5] | |
| |
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]
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.
The specific name, dumerilianus, is in honor of French herpetologist André Marie Constant Duméril. [7]
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 8 people fed on with enough for leftovers for the next day. The exact size of this specimen is unknown. [8]
Sexual dimorphism is present like in most turtles, with males being larger with wider heads and longer tails. [8]
It is considered morphologically similar to the another podocnemidid, the Madagascan big-headed turtle, which is similarly omnivorous unlike the herbivorous genus Podocnemis . [8] [9]
P. dumerilianus is found in Brazil (Amazonas, Pará), Colombia, French Guiana, Venezuela, Ecuador, and possibly in Peru. [5]
The preferred natural habitats of P. dumerilianus are rivers and freshwater swamps, preferring igapó and other blackwater river systems. [5] [10]
While not territorial, it's 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. [8]
Less agile swimmers than other podocnemidid turtles, they're 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. [8]
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 avaliable. [11] As undigested seeds have been observed in the intestines, it may be an important seed disperser. [8] 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. [8]
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. [8]
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. [8]
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. [8]
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.
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.
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.
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.
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.
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.
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.
Hydromedusa is a turtle genus in the family Chelidae, commonly known as the South American snake-necked turtles. They are quite closely related to the South American side-necked swamp turtles (Acanthochelys) and the snake-necked turtles of the Australian-Melanesian region (Chelodina), but less closely to the spine-necked river turtles of South America (Podocnemididae) which belong to a more modern lineage of Pleurodira.
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.
River turtle may refer to:
August Friedrich Schweigger was a German naturalist born in Erlangen. He was the younger brother of scientist Johann Salomo Christoph Schweigger (1779-1857).
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.
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.
Bauruemys is an extinct genus of turtles in the family Podocnemididae.
The Presidente Prudente Formation is a geological formation of the Bauru Group in the Paraná Basin, located in Brazil whose strata date back to the Late Campanian to Early Maastrichtian.
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.
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.
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.
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.
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