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Pecora

Pecora
Temporal range: 50–0 Ma
Early Eocene - recent
Pronghorn antelope.jpg
Pronghorn antelope
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Class: Mammalia
Order: Artiodactyla
Suborder: Ruminantia
Infraorder: Pecora
Flower, 1883
Families

 Cervidae
 †Gelocidae
 †Palaeomerycidae
 †Hoplitomerycidae
 †Climacoceratidae
 Giraffidae
 Antilocapridae
 †Leptomerycidae
 Moschidae
 Bovidae


 Cervidae
 †Gelocidae
 †Palaeomerycidae
 †Hoplitomerycidae
 †Climacoceratidae
 Giraffidae
 Antilocapridae
 †Leptomerycidae
 Moschidae
 Bovidae

The Pecora are an infraorder of even-toed hoofed mammals with ruminant digestion (Ruminantia, a clade within the Artiodactyla). Most members of Pecora have cranial appendages projecting from their frontal bones; only two extant genera lack them, Hydropotes and Moschus. The name “Pecora” comes from the Latin word pecus, which means “horned livestock”. Although most pecorans have cranial appendages, only some of these are properly called “horns”, and many scientists agree that these appendages did not arise from a common ancestor, but instead evolved independently on at least two occasions. Likewise, while Pecora as a group is supported by both molecular and morphological studies, morphological support for interrelationships between pecoran families is disputed.

The first fossil ruminants appeared in the mid-Eocene, and were small, likely omnivorous, forest-dwellers. Artiodactyls with cranial appendages first occur in the early Miocene. The appearance of the Pecora during the Miocene suggests that their rapid diversification may correspond to the climate change events of that epoch.

Current attempts to determine the relationships among pecoran families (as well as all artiodactyls) rely on molecular studies, as little consensus exists in morphological studies. The different families within the Pecora are recognized as valid by different groups of scientists.and sources therein, pp. 4–5

The Pecora share characteristics with other Artiodactyls, including a four-chambered stomach, and a paraxonic foot, meaning that it supports weight on the third and fourth digits. Janis and Scott (1987) recognize several characteristics that distinguish Pecora from their sister taxon, Tragulina: an astragalus with parallel sides, a loss of the trapezium, and differences in parts of the skull such as the petrosal.


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Wikipedia

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