Acratocnus | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Pilosa |
Family: | † Megalocnidae |
Genus: | † Acratocnus Anthony 1916 |
Type species | |
†Acratocnus odontrigonus Anthony, 1916 | |
Species | |
| |
Synonyms | |
HabanocnusMayo, 1978 |
Acratocnus is an extinct genus of ground sloths that were found on Cuba, Hispaniola (today the Dominican Republic and Haiti), and Puerto Rico.
Like all of the Antillean sloths, Acratocnus was formerly thought on the basis of morphological evidence to be a member of the family Megalonychidae, which was also thought to include Choloepus , the two-toed tree sloths. Recent molecular evidence has clarified that Caribbean sloths represent a separate basal branch of the sloth radiation, [1] [2] now placed in the family Megalocnidae. [1]
Fossils of Acratocnus were found on the islands of Puerto Rico, Cuba, and Hispaniola, where they inhabited the montane forests of the highlands. The Puerto Rican ground sloth, Acratocnus odontrigonus is known from several poorly documented cave excavations in northwestern Puerto Rico. The various species are regarded as being semi-arboreal because of their (relatively speaking) small size and their large hooked claws.
The various species of Acratocnus ranged in weight from 50 to 150 pounds (23 to 68 kg), and were thus much larger than living tree sloths (genera Choloepus and Bradypus ), which do not exceed 20 pounds (9.1 kg).[ citation needed ]
As with many sloth fossils, these species of sloth have not been radiometrically dated. [3] It is suggested[ by whom? ] that the Puerto Rican and Hispaniolan Acratocnus species survived into the late Pleistocene but disappeared by the mid-Holocene.[ citation needed ] The related Cuban ground sloth, Megalocnus rodens, survived until at least c. 6600 BP, [4] and the latest survival reported for any of the Antillean sloths is c. 5000 BP, for the Hispaniolan Neocnus comes, [4] based on AMS radiocarbon dating. The cause(s) of their extinctions may have been climatic changes, or more likely, human hunting by the indigenous peoples of the Caribbean. [4]
Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. Ground sloths varied widely in size, with the largest genera Megatherium and Eremotherium being around the size of elephants. Ground sloths are a paraphyletic group, as living tree sloths are thought to have evolved from ground sloth ancestors.
Nesophontes, sometimes called West Indies shrews, is the sole genus of the extinct, monotypic mammal family Nesophontidae in the order Eulipotyphla. These animals were small insectivores, about 5 to 15 cm long, with a long slender snout and head and a long tail. They were endemic to the Greater Antilles, in Cuba, Hispaniola, Puerto Rico, the United States Virgin Islands, and the Cayman Islands.
Choloepus is a genus of xenarthran mammals of Central and South America within the monotypic family Choloepodidae, consisting of two-toed sloths, sometimes also called two-fingered sloths. The two species of Choloepus, Linnaeus's two-toed sloth and Hoffmann's two-toed sloth, were formerly believed on the basis of morphological studies to be the only surviving members of the sloth family Megalonychidae, but have now been shown by molecular results to be closest to extinct ground sloths of the family Mylodontidae.
Megalonychidae is an extinct family of sloths including the extinct Megalonyx. Megalonychids first appeared in the early Oligocene, about 35 million years (Ma) ago, in southern Argentina (Patagonia). There is, however, one possible find dating to the Eocene, about 40 Ma ago, on Seymour Island in Antarctica. They first reached North America by island-hopping across the Central American Seaway, about 9 million years ago, prior to formation of the Isthmus of Panama about 2.7 million years ago. Some megalonychid lineages increased in size as time passed. The first species of these were small and may have been partly tree-dwelling, whereas the Pliocene species were already approximately half the size of the huge Late Pleistocene Megalonyx jeffersonii from the last ice age.
Paralouatta is a platyrrhine genus that currently contains two extinct species of small primates that lived on the island of Cuba.
The fauna of Puerto Rico is similar to other island archipelago faunas, with high endemism, and low, skewed taxonomic diversity. Bats are the only extant native terrestrial mammals in Puerto Rico. All other terrestrial mammals in the area were introduced by humans, and include species such as cats, goats, sheep, the small Indian mongoose, and escaped monkeys. Marine mammals include dolphins, manatees, and whales. Of the 349 bird species, about 120 breed in the archipelago, and 47.5% are accidental or rare.
Neocnus is an extinct genus of ground sloth, whose species ranged across Cuba and Hispaniola. Neocnus would have resembled a typical ground sloth, though much smaller, with a longer tail and a broad trunk, as well as lissome limbs and long claws. This sloth was known for having caudal vertebrae that were broad, a trait shared with other ground sloths, indicating that this animal, like the tamandua of today, likely used its tail to stand upright. The caniniform teeth of the Neocnus were large and triangular, and its skull was deep and had a large, sagittal crest which, when used with the deep mandible likely allowed strong exertion by the masticatory muscles.
The Jamaican monkey is an extinct species of New World monkey that was endemic to Jamaica. It was first uncovered at Long Mile Cave by Harold Anthony in 1920.
Megalocnus is a genus of extinct ground sloths that were native to Cuba during the Pleistocene and Holocene epochs. They were among the largest of the Caribbean sloths (Megalocnidae), with individuals estimated to have weighed up to 270 kg to 200 kg, around the size of a black bear when alive. Its relatives include other megalocnid sloths, such as Acratocnus, Mesocnus, Miocnus, Neocnus andParocnus. The former species M. zile from Hispaniola is currently thought to be a junior synonym of Parocnus serus.
Imagocnus is an extinct genus of ground sloth from the Early Miocene (Burdigalian) Lagunitas Formation of Cuba.
The Caribbean bioregion is a biogeographic region that includes the islands of the Caribbean Sea and nearby Atlantic islands, which share a fauna, flora and mycobiota distinct from surrounding bioregions.
The Hispaniola monkey is an extinct primate that was endemic on the island of Hispaniola, in the present-day Dominican Republic. The species is thought to have gone extinct around the 16th century. The exact timing and cause of the extinction are unclear, but it is likely related to the settlement of Hispaniola by Europeans after 1492.
The mammalian order Pilosa, which includes the sloths and anteaters, includes various species from the Caribbean region. Many species of sloths are known from the Greater Antilles, all of which became extinct over the last millennia, but some sloths and anteaters survive on islands closer to the mainland.
A unique and diverse albeit phylogenetically restricted mammal fauna is known from the Caribbean region. The region—specifically, all islands in the Caribbean Sea and the Bahamas, Turks and Caicos Islands, and Barbados, which are not in the Caribbean Sea but biogeographically belong to the same Caribbean bioregion—has been home to several families found nowhere else, but much of this diversity is now extinct.
Megalocnidae is an extinct family of sloths, native to the islands of the Greater Antilles from the Early Oligocene to the Mid-Holocene. They are known from Cuba, Hispaniola and Puerto Rico, but are absent from Jamaica. While they were formerly placed in the Megalonychidae alongside two-toed sloths and ground sloths like Megalonyx, recent mitochondrial DNA and collagen sequencing studies place them as the earliest diverging group basal to all other sloths. They displayed significant diversity in body size and lifestyle, with Megalocnus being terrestrial and probably weighing several hundred kilograms, while Neocnus was likely arboreal and similar in weight to extant tree sloths, at less than 10 kilograms.
Parocnus is an extinct genus of sloth native to Cuba and Hispaniola, belonging to the family Megalocnidae. It was a terrestrial ground sloth, being the second largest Caribbean sloth after Megalocnus.