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Bear-dog
Amphicyonidae is an extinct family of terrestrial carnivorans belonging to the suborder Caniformia. They first appeared in North America in the middle Eocene (around 45 mya), spread to Europe by the late Eocene (35 mya), and further spread to Asia and Africa by the early Miocene (23 mya). They had largely disappeared worldwide by the late Miocene (5 mya), with the latest recorded species at the end of the Miocene in Africa. They were among the first carnivorans to evolve large body size. Amphicyonids are colloquially referred to as "bear-dogs". Taxonomy The family was erected by Haeckel in 1866 (also attributed to Trouessart 1885). Their exact position has long been disputed. Early paleontologists usually defined them as members of Canidae (the dog family) or Ursidae (the bear family), but the modern consensus is that they form their own family. Some researchers have defined it as the sister clade to ursids, based on morphological analysis of the ear region. However, cladistic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphicyoninae
Amphicyoninae is a subfamily of extinct amphicyonids, large Terrestrial animal, terrestrial carnivores sometimes called "bear-dogs", belonging to the suborder Caniformia, which inhabited North America, Eurasia, and Africa from the middle Eocene to the late Miocene. Amphicyoninae was first named by Trouessart (1885). It was assigned to Canidae by Matthew (1902), to Ursidae by Ginsburg (1977) and to Amphicyonidae by Hunt (1998). Genera include: *''Amphicyon'', found in both Europe and N. America *''Cynelos'', synonyms include ''Absonodaphoenus'' (from Florida) and ''Hecubides'' (from Africa), endemic to N. America *''Cynodictis'' *''Ischyrocyon'' (syn. ''Hadrocyon''), endemic to N. America *''Goupilictis'' *''Magericyon'' *''Paludocyon'' *''Pliocyon'', endemic to N. America *''Pseudocyon'' (syn. ''Amphicyonopsis''), endemic to Europe and N. America Fossil distribution Specimens have been recovered from: *Midway Site, Gadsden County, Florida ~18.9—18.8 Ma. *Rabbitt Creek S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphoenus Vetus Skull
''Daphoenus'' is an extinct genus of amphicyonids, a group colloquially known as "bear-dogs". It includes not just some of the best preserved material out of any amphicyonid, but also the earliest members of the family, first appearing in the Eocene, middle Eocene and surviving into the Rupelian, Early Oligocene. The members of the genus are rather small compared to some of its later relatives, such as ''Amphicyon'' or ''Ysengrinia'', ranging in size from comparable to a house cat to a small wolf. It was widely distributed across North America, with most of its remains being discovered in the White River Formation, White River Group of the Great Plains, though the John Day Beds of Oregon and the Cypress Hills Formation in Saskatchewan also represent important fossil sites. Other specimens have been described from localities in Texas, Georgia (country), Georgia, Florida, and California. Taxonomy The first fossils of ''Daphoenus vetus'' were collected by John Evans in 1849, befor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphicynodontidae
Amphicynodontidae is a probable clade of extinct arctoids. While some researchers consider this group to be an extinct subfamily of bears, a variety of morphological evidence links amphicynodontines with pinnipeds, as the group were semi-aquatic otter-like mammals. In addition to the support of the pinniped–amphicynodontine clade, other morphological and some molecular analyses support bears being the closest living relatives to pinnipeds. According to McKenna and Bell (1997) Amphicynodontinae are classified as stem-pinnipeds in the superfamily Phocoidea. Fossils of these mammals have been found in Europe, North America and Asia. Amphicynodontines should not be confused with Amphicyonids (bear-dogs), a separate family of Carnivora which is a sister clade to arctoids within the caniforms Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs (wolves, foxes, etc.), bears, raccoons, and mustelids. The Pinnipedia ( s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caniformia
Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include Canidae, dogs (Wolf, wolves, foxes, etc.), bears, raccoons, and Mustelidae, mustelids. The Pinnipedia (pinniped, seals, walruses and sea lions) are also assigned to this group. The center of diversification for the Caniformia is North America and northern Eurasia. Caniformia stands in contrast to the other suborder of Carnivora, the Feliformia ("cat-like" carnivorans), the center of diversification of which was in Africa and United Nations geoscheme for Asia#Southern Asia, southern Asia. Description Most members of this group have nonretractile claws (the Fisher (animal), fisher, marten, sea otter (Forepaw, forepaws only), red panda, and Bassariscus astutus, ringtail, and some foxes have retractile or semi-retractile claws) and tend to be plantigrade (with the exception of the Canidae). Other traits that separate the Caniformia from the Feliformia is that caniforms have longer ja ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Bulla
The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal. It originates as a separate bone (tympanic bone), which in some mammals stays separate through life. Evolutionarily, a portion of it is derived from the angular bone of the reptilian lower jaw. Surfaces Its postero-superior surface is concave, and forms the anterior wall, the floor, and part of the posterior wall of the bony ear canal. Medially, it presents a narrow furrow, the ''tympanic sulcus'', for the attachment of the tympanic membrane. Its antero-inferior surface is quadrilateral and slightly concave; it constitutes the posterior boundary of the mandibular fossa, and is in contact with the retromandibular part of the parotid gland. Borders Its lateral border is free and rough, and gives attachment to the cartilaginous part of the ear canal. Internally, the tympanic pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittal Crest
A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are exceptionally strong jaw muscles. The sagittal crest serves primarily for attachment of the temporalis muscle, which is one of the main chewing muscles. Development of the sagittal crest is thought to be connected to the development of this muscle. A sagittal crest usually develops during the juvenile stage of an animal in conjunction with the growth of the temporalis muscle, as a result of convergence and gradual heightening of the temporal lines. Function A sagittal crest tends to be present on the skulls of adult animals that rely on powerful biting and clenching of their teeth, usually as a part of their hunting strategy. Skulls of some dinosaur species, including tyrannosaurs, possessed well developed sagittal crests. Among mammals, dogs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condylarthra
Condylarthra is an informal group – previously considered an order – of extinct placental mammals, known primarily from the Paleocene and Eocene epochs. They are considered early, primitive ungulates and is now largely considered to be a wastebasket taxon, having served as a dumping ground for classifying ungulates which had not been clearly established as part of either Perissodactyla or Artiodactyla, being composed thus of several unrelated lineages. Taxonomic history Condylarthra always was a problematic group. When first described by , Phenacodontidae was the type and only family therein. , however, raised Condylarthra to an order and included a wide range of diverse placentals with generalized dentitions and postcranial skeletons. More recent researchers (i.e. post-WW2) have been more restrictive; either including only a limited number of taxa, or proposing that the term should be abandoned altogether. Due to their primitive characteristics condylarths have been consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctocyonidae
Arctocyonidae (from Greek ''arktos'' and ''kyôn'', "bear/dog-like") is an extinct, possibly polyphyletic family of placental mammals which lived from the late Cretaceous to the early Eocene. They were initially regarded as creodonts, though have since been reassigned to an order of their own, the Arctocyonia. Some have suggested that arctocyonids are ancestral to modern-day artiodactyls, or that they form a sister group. However, more recent phylogenetic analyses suggest that arctocyonids may represent an artificial grouping of extinct ungulates, or that they might be an assemblage of unrelated placentals related to pangolins, pantodonts, and periptychids. Members of Arctocyonidae are characterised by long skulls, with large sagittal crests and very large canines. In the case of '' Arctocyon'' proper, the lower canines especially were large enough to require a diastema on the upper jaw to accommodate them. Arctocyonids varied considerably in size and morphology. Smaller gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinniped
Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant taxon, extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals), with 34 extant species and more than 50 extinct species described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular phylogenetics, molecular evidence supports them as a monophyletic group (descended from one ancestor). Pinnipeds belong to the suborder Caniformia of the order Carnivora; their closest living relatives are musteloids (Mustelidae, weasels, Procyonidae, raccoons, skunks and red pandas), having diverged about 50 million years ago. Seals range in size from the and Baikal seal to the and southern elephant seal. Several species exhibit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemicyoninae
Hemicyoninae is an extinct subfamily of Ursidae, often called dog bears (literally "half dog" (Ancient Greek, Greek: )). They were bear-like carnivorans living in Europe, North America, Africa and Asia during the Oligocene through Miocene epochs 33.9–5.3 Annum, Ma, existing for approximately . They are sometimes classified as a separate family (biology), family. Systematics The hemicyonines consists of three tribes: the Cephalogalini, Phoberocyonini, and Hemicyonini. In the past the hemicyonines were evaluated into family level (Hemicyonidae). However the vast majority of papers and researchers that cover the evolution of bears often classified them as an extinct subfamily of ursids or stem-bears. The genus ''Agriotherium'' was once classified as a hemicyonine but recent work has shown the genus is a crown-ursid. * Subfamily †Hemicyoninae Frick, 1926 ** Tribe †Cephalogalini de Bonis, 2013 *** †''Adelpharctos'' de Bonis, 1971 **** †''Adelpharctos ginsburgi'' de Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
