Plesiadapiformes
Encyclopedia
Plesiadapiformes is an extinct order
of mammal
s. It is either closely related to the primate
s or a precursor to them. Many are too derived to be ancestral to primates, but the earliest Plesiadapiformes have teeth that are strongly indicative of a common ancestor. Purgatorius
is believed to be close to the last common ancestor of primates and Plesiadapiformes.
Plesiadapiformes first appear in the fossil record in the Cretaceous
period, though many were extinct by the beginning of the Eocene
. It is possible that they are the first mammals to have developed finger nails in place of claw
s.
One possible classification table of plesiadapiform families is listed below.
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of mammal
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. It is either closely related to the primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
s or a precursor to them. Many are too derived to be ancestral to primates, but the earliest Plesiadapiformes have teeth that are strongly indicative of a common ancestor. Purgatorius
Purgatorius
Purgatorius is the genus of the four extinct species believed to be the earliest example of a primate or a proto-primate, a primatomorph precursor to the Plesiadapiformes...
is believed to be close to the last common ancestor of primates and Plesiadapiformes.
Plesiadapiformes first appear in the fossil record in 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...
period, though many were extinct by the beginning of the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
. It is possible that they are the first mammals to have developed finger nails in place of claw
Claw
A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...
s.
One possible classification table of plesiadapiform families is listed below.
- ORDER PLESIADAPIFORMES
- Family Micromomyidae
- Superfamily Paromomyoidea
- Family Paromomyidae
- Family Picromomyidae
- Family Palaechthonidae
- Family Picrodontidae
- Family Microsyopidae
- Superfamily Plesiadapoidea
- Family Chronolestidae
- Family PlesiadapidaePlesiadapidaePlesiadapidae is a family of plesiadapiform mammals related to primates known from the Paleocene and Eocene of North America, Europe, and Asia...
- Superfamily Carpolestoidea
- Family CarpolestidaeCarpolestidaeCarpolestidae is a family of primate-like Plesiadapiformes that were prevalent in North America and Asia from the mid Paleocene through the early Eocene. Typically, they are characterized by two large upper posterior premolars and one large lower posterior premolar. They weighed about 20-150g, and...
- Family Carpolestidae