Triconodonta
Encyclopedia
Triconodonta is the generic name for a group of early mammal
s which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic
and the Cretaceous
. They are one of the groups that can be classified as mammals by any definition. Several other extinct groups of Mesozoic
animals that are traditionally considered to be mammals (such as Morganucodonta
and Docodonta
) are now placed just outside Mammalia by those who advocate a 'crown-group' definition of the word "mammal".
Their name, meaning "Three conical teeth", is based on one of their fundamental characteristics. They had the typical morphology of the proto-mammals: small, furry, tetrapod animals with long tails. They probably had a nocturnal lifestyle to avoid dinosaur
predators, coming out from their burrows after dusk to hunt for small reptiles and insects. However, recent evidence from China
suggests that some triconodonts such as Repenomamus
were indeed able to take on small dinosaurs. http://www.newscientist.com/channel/life/dn6874.html.
after Marisol Montellano, James A. Hopson, James M. Clark (2008) and Thomas Martin & Alexander O. Averianov (2006) for Klameliidae
.
Cladogram after Kielan-Jaworowska, Cifelli & Luo (2004), Gao et al. (2010) and Thomas Martin & Alexander O. Averianov (2006) for Klameliidae
.
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 which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
and the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
. They are one of the groups that can be classified as mammals by any definition. Several other extinct groups of 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...
animals that are traditionally considered to be mammals (such as Morganucodonta
Morganucodonta
The morganucodonts are an extinct group of important animals that seem to represent the earliest of mammals. These were shrew-sized, likely warm-blooded and possibly possessed mammary glands....
and Docodonta
Docodonta
Docodonta is an order of extinct proto-mammals 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...
) are now placed just outside Mammalia by those who advocate a 'crown-group' definition of the word "mammal".
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
predators, coming out from their burrows after dusk to hunt for small reptiles and insects. However, recent evidence from China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
suggests that some triconodonts such as Repenomamus
Repenomamus
Repenomamus is the largest mammal known from the Cretaceous period of Manchuria, and it is the mammal for which there is the best evidence that it fed on dinosaurs. It is not possible to determine if Repenomamus actively hunted live dinosaurs or scavenged dead dinosaurs.-Paleobiology:Repenomamus...
were indeed able to take on small dinosaurs. http://www.newscientist.com/channel/life/dn6874.html.
Phylogeny
CladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
after Marisol Montellano, James A. Hopson, James M. Clark (2008) and Thomas Martin & Alexander O. Averianov (2006) for Klameliidae
Klameliidae
The Klameliidae are a family of extinct mammals from the Early Creataceous, belonging to the triconodonts. It contains only two species: Ferganodon narynensis and Klamelia zhaopengi....
.
Cladogram after Kielan-Jaworowska, Cifelli & Luo (2004), Gao et al. (2010) and Thomas Martin & Alexander O. Averianov (2006) for Klameliidae
Klameliidae
The Klameliidae are a family of extinct mammals from the Early Creataceous, belonging to the triconodonts. It contains only two species: Ferganodon narynensis and Klamelia zhaopengi....
.