|
|
|
|
Carnivoramorpha
|
| |
|
| |
Carnivoramorpha are a clade of mammals that includes the modern order Carnivora and its closest extinct relatives in the Miacoidea (Miacidae and Viverravidae), but excludes the creodonts. The order Creodonta are a sister taxon to the Carnivoramorpha dating back 58.7 million years ago. The oldest carnivoramorphans are viverravids, and the oldest generally accepted viverravid is Protictis dated at 63 million years ago.
Discussion
Ask a question about 'Carnivoramorpha' Start a new discussion about 'Carnivoramorpha' Answer questions from other users |
Encyclopedia
Carnivoramorpha are a clade of mammals that includes the modern order Carnivora and its closest extinct relatives in the Miacoidea (Miacidae and Viverravidae), but excludes the creodonts. The order Creodonta are a sister taxon to the Carnivoramorpha dating back 58.7 million years ago. The oldest carnivoramorphans are viverravids, and the oldest generally accepted viverravid is Protictis dated at 63 million years ago. Ravenictis from Canada may also be a carnivoramorphan and this would extend the date back to at least 65 million years ago.
Definition
The First International Phylogenetic Nomenclature Meeting (2004) states: “Modification of the upper fourth premolar (P4) and lower first molar (m1) as carnassial teeth has been considered a synapomorphy for carnivorans, here we follow a recent convention employing the name Carnivoramorpha for that clade and restricting the meaning of the widely known name Carnivora to the smaller crown clade delimited by the extant species regarded as carnivorans. Accordingly, Carnivoramorpha is here defined as the smallest clade containing the earliest organism to have the P4/m1 carnassial shear synapomorphic with that in Felis catus. Morphological and molecular evidence indicates that the carnivoran Aeluroid, Cynoid and Arctoid clades share an exclusive common ancestry. Species representing these three major carnivoran clades are used as specifiers in the definition of Carnivora, which is here defined as the smallest clade containing Felis catus, Canis familiaris and Mustela erminea.”
Evolution
When Carnivoramorpha first emerged in the Paleocene they were not the only group of terrestrial meat-eating mammals present. The Creodonta, composed of the Oxyaenids (robust, short-limbed wolverine forms) and the Hyaenodontids (slender-limbed, semi-cursorial forms), were also present and were well on their way toward their maximum speciation, which occurred in the middle Eocene era (Stiles, 2005). Judging from their dentitions, many were specialized meat eaters and must be included in any study addressing the evolution of mammalian carnivory. In North America few creodonts survived past the Eocene, and all were extinct by the late Oligocene. The taxonomic decline of Creodonta at the end of the Eocene coincided with the beginning of the speciation and radiation of the Carnivora, and the origination of most modern carnivore families. Regardless of whether this was taxonomic displacement or replacement this pattern has generated the hypothesis that the diversification of carnivorans was suppressed by the incumbent creodonts early in their history.
The first carnivores likely arose from a small insectivorous mammal found in the middle Eocene era, a time of rapid differentiation for mammalian species. The earliest known members of the carnivores are rarely found as fossilized bones; most often they are recovered strictly as tooth samples and partial jaw fragments. These pioneering species are classified in the Miacidae clade, which is morphologically separable into two lineages, the Viverravines and the Miacines. Both members of these lineages display dental features that are typically characteristic of carnivores, shearing teeth known as carnassials along with the presence of a transverse jaw hinge. The main difference in these early Miacidae members is found in their dentition, the Miacines resemble the caniforms while the Viverravines resemble the feliforms.
Classification & Phylogeny
- Clade Carnivoramorpha (basal to Carnivora but without Creodonts)
- Superfamily †Miacoidea
- Family †Miacidae
- genera: Chailicyon, Eostictis, Ictognathus, Miacis, Miocyon, Oodectes, Palaearctonyx, Paramiacis, Paroodectes, Prodaphaemus, Quercgyale, Tapocyon, Uintacyon, Vassacyon, Vulpavus, Xinyuictis, Ziphacodon
- Family †Viverravidae
- Order Carnivora
Carnivoramorpha
|?- †Aelurotherium
|?- †Eosictis
|?- †Elmensius
|?- †Intyrictis vanvaleni
|?- †Notoamphicyon
|?- †Ravenictis krausei or cimolestan
|?- †Vishnucyon
`--+-- †Miacoidea (paraphyletic)
`--+-- †Viverravidae [Viverraroidea]
`--+-- †Miacidea (paraphyletic)
`--+-- †Oodectes
`--+-- †Vulpavus
`--+-- †Miacis
`--+--+-- †Tapocyon
| `--+-- †Miacis sylvestris
| `-- †Prohesperocyon wilsoni
`--+-- †Quergygale angustidens
`-- †Nimravidae? (very unstable position with respect to Carnivora -
unresolved as of August 2007)
`-- Carnivora
`-- Caniformia
`-- Aeluroidea
|
| |
|
|
