Docodonta
Encyclopedia
Docodonta is an order of extinct proto-mammal
s that lived during the mid- to late-Mesozoic
era. Their most distinguishing physical features were their relatively sophisticated set of molars
, from which the order gets its name. In the fossil record, Docodonta is represented primarily by isolated teeth and bits of jawbones. While most of these specimens have been found across former Laurasia
(modern-day North America
, Europe
, and Asia
), some have also been found from Gondwana
(modern-day India
and Southern Hemisphere
).
The exact phylogenetic position of the docodonts depends on the method one is using. From a cladistic point of view, docodonts are advanced mammaliaforms just outside the Mammalia proper. From a 'traditional' point of view, the docodonts are basal mammals and usually placed in the paraphyletic subclass Allotheria
.
Docodonts are thought to have been primarily herbivorous
or insectivorous
, although Castorocauda
has teeth which suggest it ate fish.
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s that lived during the mid- to late-Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
era. Their most distinguishing physical features were their relatively sophisticated set of molars
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
, from which the order gets its name. In the fossil record, Docodonta is represented primarily by isolated teeth and bits of jawbones. While most of these specimens have been found across former Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...
(modern-day North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
), some have also been found from Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
(modern-day India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
).
The exact phylogenetic position of the docodonts depends on the method one is using. From a cladistic point of view, docodonts are advanced mammaliaforms just outside the Mammalia proper. From a 'traditional' point of view, the docodonts are basal mammals and usually placed in the paraphyletic subclass Allotheria
Allotheria
Allotheria was a branch of successful Mesozoic mammals. The most important characteristic was the presence of lower molariform teeth equipped with two longitudinal rows of cusps...
.
Docodonts are thought to have been primarily herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
or insectivorous
Insectivore
An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures. An alternate term is entomophage, which also refers to the human practice of eating insects....
, although Castorocauda
Castorocauda lutrasimilis
Castorocauda was a genus of small, semi-aquatic relative of mammals living in the mid Jurassic period, around 154 million years ago, found in lakebed sediments of the Daohugou Beds of Inner Mongolia...
has teeth which suggest it ate fish.