Artiodactyls are placental mammals belonging to the order Artiodactyla. Typically, they are ungulates which bear weight equally on two of their five toes. The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, most perissodactyls bear weight on an odd number of the five toes. Another difference between the two orders is that many artiodactyls digest plant cellulose in one or more stomach chambers rather than in their intestine. Molecular biology, along with new fossil discoveries, has found that cetaceans fall within this taxonomic branch, being most closely related to hippopotamuses. Some modern taxonomists thus apply the name Cetartiodactyla to this group, while others opt to include cetaceans within the existing name of Artiodactyla. Some researchers use "even-toed ungulates" to exclude cetaceans and only include terrestrial artiodactyls, making the term paraphyletic in nature.
The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, sheep and goats. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, the family Bovidae consists of 11 major subfamilies and thirteen major tribes. The family evolved 20 million years ago, in the early Miocene.
Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The process, which takes place in the front part of the digestive system and therefore is called foregut fermentation, typically requires the fermented ingesta to be regurgitated and chewed again. The process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination. The word "ruminant" comes from the Latin ruminare, which means "to chew over again".
The Giraffidae are a family of ruminant artiodactyl mammals that share a recent common ancestor with deer and bovids. This family, once a diverse group spread throughout Eurasia and Africa, presently comprises only two extant genera, the giraffe and the okapi. Both are confined to sub-Saharan Africa: the giraffe to the open savannas, and the okapi to the dense rainforest of the Congo. The two genera look very different on first sight, but share a number of common features, including a long, dark-coloured tongue, lobed canine teeth, and horns covered in skin, called ossicones.
Moschidae is a family of pecoran even-toed ungulates, containing the musk deer (Moschus) and its extinct relatives. They are characterized by long "saber teeth" instead of horns, antlers or ossicones, modest size and a lack of facial glands. While various Oligocene and Miocene pecorans were previously assigned to this family, recent studies find that most should be assigned to their own clades, although further research would need to confirm these traits. As a result, Micromeryx, Hispanomeryx, and Moschus are the only undisputed moschid members, making them known from at least 18 Ma. The group was abundant across Eurasia and North America during the Miocene, but afterwards declined to only the extant genus Moschus by the early Pleistocene.
Musk deer can refer to any one, or all eight, of the species that make up Moschus, the only extant genus of the family Moschidae. Despite being commonly called deer, they are not true deer belonging to the family Cervidae, but rather their family is closely related to Bovidae, the group that contains antelopes, bovines, sheep, and goats. The musk deer family differs from cervids, or true deer, by lacking antlers and preorbital glands also, possessing only a single pair of teats, a gallbladder, a caudal gland, a pair of canine tusks and—of particular economic importance to humans—a musk gland.
Pecora is an infraorder of even-toed hoofed mammals with ruminant digestion. 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 "cattle". 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 Antilocapridae are a family of ruminant artiodactyls endemic to North America. Their closest extant relatives are the giraffids. Only one species, the pronghorn, is living today; all other members of the family are extinct. The living pronghorn is a small ruminant mammal resembling an antelope.
The Cetruminantia are a clade made up of the Cetancodontamorpha and their closest living relatives, the Ruminantia.
Micromeryx is an extinct genus of musk deer that lived during the Miocene epoch. Fossil remains were found in Europe and Asia. The earliest record (MN4) of the genus comes from the Sibnica 4 paleontological site near Rekovac in Serbia.
Artiofabula is a clade made up of the Suina and the Cetruminantia. The clade was found in molecular phylogenetic analyses and contradicted traditional relationships based on morphological analyses.
This paleomammalogy list records new fossil mammal taxa that were described during the year 2014, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.
The Gelocidae are an extinct family of hornless ruminantia that are estimated to have lived during the Eocene and Oligocene epochs, from 36 MYA to 6 MYA. The family generally includes ruminants with dental traits of both the Tragulina and Pecora, making it a notorious wastebasket taxon with unresolved affinities.
The Liushu Formation is a geological formation in Gansu province, China that spans up to 100 m thick and is widely distributed within the Linxia Basin, with a paleomagnetic age between 11 and 6.4 mya.
Giraffomorpha is a clade of pecoran ruminants containing the superfamilies Palaeomerycoidea (Palaeomerycidae) and Giraffoidea, of which the giraffe and okapi of the Giraffidae are the only extant members of the once-diverse clade as a result of a decline in diversity after the Miocene as a result of declines in temperatures. The clade is defined by the presence of ossicones, suggesting that the feature was developed as a result of basal, related evolutions between the two superfamilies rather than as an instance of parallel evolution. Giraffomorpha is also characterized by a lack of articular fossettes (hollows) in metatarsal bones III-IV.
Tethytragus was a genus of caprine bovid that lived in the Middle and Late Miocene.
Qurliqnoria is an extinct genus of caprine bovid that inhabited Eurasia during the Neogene period.
Dremotherium is an extinct genus of ruminant that inhabited Eurasia during the Palaeogene and Neogene periods.
Pseudamphimeryx is an extinct genus of Palaeogene artiodactyls belonging to the Amphimerycidae that was endemic to the central region of western Europe and lived from the Middle to Late Eocene. It was first erected in 1910 by the Swiss palaeontologist Hans Georg Stehlin, who assigned to it multiple species and noted specific differences from another amphimerycid Amphimeryx. As of present, it is known by six species, although the validity of P. valdensis has been questioned while the earliest-appearing species P. schosseri has been suggested to not be an amphimerycid.
Amphimerycidae is an extinct family of artiodactyls that was endemic to western Europe that lived from the Middle Eocene to the Early Oligocene. With a taxonomic history extending as far back as 1804, the family was formally recognized by the Swiss palaeontologist Hans Georg Stehlin in 1910 and contains two genera: Amphimeryx and Pseudamphimeryx. Both amphimerycid genera are very similar to each other in terms of skull and dental anatomy but do have specific differences from each other. Both genera are best known from their fused cuboid bone and navicular bone, which together make up a single "cubonavicular bone" of the hind legs. This trait had long been used in support of the idea that they were ruminants by taxonomists. However, their classification to the Ruminantia had also been rejected by other taxonomists later on due to differences in dentition; the systematic position of the Amphimerycidae and close relatives in relation to the wider Artiodactyla, as a result, is unclear.
