This family, which consisted of 5 species in 4 genera, lived in the Greater Antilles plus Anguilla and St. Martins. All species are extinct, but it is likely that populatons of at least two genera, Amblyrhiza and Clidomys, coexisted with humans in the West Indies. The name "quemi" was the native name given to an animal described by early Spanish explorers. It was said to be slightly larger than a hutia (Capromyidae) and was a source of food for natives. If the quemi was in fact a heptaxodontid, then this family became extinct soon after the Spanish conquest of the West Indies.
Heptaxodontids were medium-sized to very large rodents. The largest, Amblyrhiza, was nearly the size of a black bear. Their skulls resembled those of nutria (Myocastoridae), but close relationship has also been suggested with the families Chinchillidae, Capromyidae, and Dinomyidae. Like nutrias, heptaxodontids had a massive rostrum, long paroccipital processes, large infraorbital canal with no accessory grove or foramen, sagittal crest often present, small bullae, and other characters. Their cheekteeth were strongly hypsodont, appearing to be made up of lamellar plates set at an angle to the long axis of the palate.
The fossil record of this family is restricted to the Pleistocene and Recent.
Families of Order Rodentia Suborder Sciurognathi Family Aplodontidae (mountain beaver, sewellel) Family Sciuridae (squirrels) Family Castoridae (beavers) Family Geomyidae (pocket gophers) Family Heteromyidae (kangaroo rats, pocket mice, and allies) Family Dipodidae (birch mice, jumping mice, jerboas) Family Muridae (familiar rates and other rodents) Family Anomaluridae (scaly-tailed squirrels) Family Pedetidae (spring hare, springhaas) Family Ctenodactylidae (gundis) Family Myoxidae (dormice and hazel mice) Suborder Hystricognathi Family Bathyergidae (mole rats, blesmols, and rats) Family Hystricidae (Old World porcupines) Family Petromuridae (rock rat or dassie rat) Family Thryonomyidae (cane rats or grasscutters) Family Erethizontidae (New World porcupines) Family Chinchillidae (Chinchillas and viscachas) Family Dinomyidae (pacarana, branick rats, false paca) Family Caviidae (cavies and guinea pigs) Family Hydrochaeridae (capybara) Family Dasyproctidae (agoutis, acouchis) Family Agoutidae (pacas) Family Ctenomyidae (tuco-tucos) Family Octodontidae (degus, coruros, rock rats) Family Abrocomidae (chinchilla rats, chinchillones) Family Echimyidae (spiny rats) Family Capromyidae (hutias, zagouties, cavies, Indian coneys) Family Heptaxodontidae (Quemi, giant hutias) Family Myocastoridae (nutria, coypu)
<<<<<<<>>>>>>>ARTIODACTYLA CARNIVORA CETACEA CHIROPTERA DASYUROMORPHIA DERMOPTERA DIDELPHIMORPHI DIPROTODONTIA HYRACOIDEA INSECTIVORA LAGOMORPHA MACROSCELIDEA MICROBIOTHERIA MONOTREMATA NOTORYCTEMORPHIA PAUCITUBERCULATA PERAMELEMORPHIA PERISSODACTYLA PHOLIDOTA PRIMATES PROBOSCIDEA RODENTIA SCANDENTIA SIRENIA TUBULIDENTATA XENARTHRA