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Dacrytherium Ovinum Skull
''Dacrytherium'' (Ancient Greek: (tear, teardrop) + (beast or wild animal) meaning "tear beast") is an extinct genus of Palaeogene artiodactyls belonging to the family Anoplotheriidae. It occurred from the Middle to Late Eocene of Western Europe and is the type genus of the subfamily Dacrytheriinae, the older of the two anoplotheriid subfamilies. ''Dacrytherium'' was first erected in 1876 by the French palaeontologist Henri Filhol, who recognised in his studies that it had dentition similar to the anoplotheriids ''Anoplotherium'' and ''Diplobune'' but differed from them by a deep preorbital fossa and a lacrimal fossa, the latter of which is where the genus name derives from. ''D. ovinum'', originally classified in '' Dichobune'', is the type species of ''Dacrytherium''. Henri Filhol named ''D. elegans'' in 1884, and Hans Georg Stehlin named the species ''D. priscum'' and ''D. saturnini'' in 1910. ''Dacrytherium'' was a medium-sized artiodactyl that is defined by specific d ... [...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] |
Archipelago
An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands. An archipelago may be in an ocean, a sea, or a smaller body of water. Example archipelagos include the Aegean Islands (the origin of the term), the Canadian Arctic Archipelago, the Stockholm Archipelago, the Malay Archipelago (which includes the Indonesian and Philippine Archipelagos), the Lucayan (Bahamian) Archipelago, the Japanese archipelago, and the Hawaiian Archipelago. Etymology The word ''archipelago'' is derived from the Italian ''arcipelago'', used as a proper name for the Aegean Sea, itself perhaps a deformation of the Greek Αιγαίον Πέλαγος. Later, usage shifted to refer to the Aegean Islands (since the sea has a large number of islands). The erudite paretymology, deriving the word from Ancient Greek ἄρχι-(''arkhi-'', "chief") and πέλαγος (''pélagos'', "sea"), proposed by Buondelmonti, can still be found. Geograph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolar
The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in the permanent teeth, permanent set of teeth, making eight premolars total in the mouth. They have at least two Cusp (dentistry), cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie Posterior (anatomy), posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth Anatomical terms of location#Proximal and distal, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphodon
''Xiphodon'' is the type genus of the extinct Paleogene, Palaeogene artiodactyl family Xiphodontidae. It, like other xiphodonts, was endemic to Western Europe and lived from the Middle Eocene up to the earliest Oligocene. Fossils from Montmartre in Paris, France that belonged to ''X. gracilis'' were first described by the French naturalist Georges Cuvier in 1804. Although he assigned the species to ''Anoplotherium'', he recognized that it differed from ''A. commune'' by its dentition and limb bones, later moving it to its own subgenus in 1822. ''Xiphodon'' was promoted to genus rank by other naturalists in later decades. It is today defined by the type species ''X. gracilis'' and two other species, ''X. castrensis'' and ''X. intermedium''. Literally meaning "sword tooth" in Ancient Greek, ''Xiphodon'' had specialized bladelike selenodont dentition, with its brachyodont (low-crowned) incisors, canine tooth, canines, and premolars having sharp edges for cutting through higher veget ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Sac
The lacrimal sac or lachrymal sac is the upper dilated end of the nasolacrimal duct, and is lodged in a deep groove formed by the lacrimal bone and frontal process of the maxilla. It connects the lacrimal canaliculi, which drain tears from the eye's surface, and the nasolacrimal duct, which conveys this fluid into the nasal cavity. Lacrimal sac occlusion leads to dacryocystitis. Structure It is oval in form and measures from 12 to 15 mm. in length; its upper end is closed and rounded; its lower is continued into the nasolacrimal duct. Its superficial surface is covered by a fibrous expansion derived from the medial palpebral ligament, and its deep surface is crossed by the lacrimal part of the orbicularis oculi, which is attached to the crest on the lacrimal bone. Histology Like the nasolacrimal duct, the sac is lined by stratified columnar epithelium with mucus-secreting goblet cells, with surrounding connective tissue. The lacrimal sac also drains the eye of deb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla
In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw. Anatomy Structure The maxilla is a paired bone - the two maxillae unite with each other at the intermaxillary suture. The maxilla consists of: * The body of the maxilla: pyramid-shaped; has an orbital, a nasal, an infratemporal, and a facial surface; contains the maxillary sinus. * Four processes: ** the zygomatic process ** the frontal process ** the alveolar process ** the palatine process It has three surfaces: * the anterior, posterior, medial Features of the maxilla include: * t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merycoidodont
Merycoidodontoidea, previously known as "oreodonts" or " ruminating hogs," are an extinct superfamily of prehistoric cud-chewing artiodactyls with short faces and fang-like canine teeth. As their name implies, some of the better known forms were generally hog-like, and the group has traditionally been placed within the Suina (pigs, peccaries and their ancestors), though some recent work suggests they may have been more closely related to camels.Spaulding, M., O'Leary, M.A. & Gatesy, J. (2009): Relationships of Cetacea (Artiodactyla) Among Mammals: Increased Taxon Sampling Alters Interpretations of Key Fossils and Character Evolution. '' PLoS ONE'' no 4(9): e7062.article/ref> "Oreodont" means "mountain teeth," referring to the appearance of the molars. Most oreodonts were sheep-sized, though some genera grew to the size of cattle. They were heavy-bodied, with short four-toed hooves and comparatively long tails. The animals would have looked rather pig- or sheep-like, but fea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparion
''Hipparion'' is an extinct genus of three-toed, medium-sized equine belonging to the extinct tribe Hipparionini, which lived about 10-5 million years ago. While the genus formerly included most hipparionines, the genus is now more narrowly defined as hipparionines from North Africa spanning the Late Miocene. ''Hipparion'' was a mixed-feeder who ate mostly grass, and lived in the savannah biome. ''Hipparion'' evolved from '' Cormohipparion'', and went extinct due to environmental changes like cooling climates and decreasing atmospheric carbon dioxide levels. Taxonomy "Hipparion" in sensu lato The genus "Hipparion" was used for over a century as a form classification to describe over a hundred species of Holartic hipparionines from the Pliocene and Miocene eras that had three toes and isolated protocones''.'' Since then, groups such as the genera '' Cormohipparion'' ''and Neohipparion'' were proposed to further sort these species, typically based on differences in skull mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Gervais
Paul Gervais (full name: François Louis Paul Gervais) (26 September 1816 – 10 February 1879) was a French palaeontologist and entomologist. Biography Gervais was born in Paris, where he obtained the diplomas of doctor of science and of medicine, and in 1835 he began palaeontological research as assistant in the laboratory of comparative anatomy at the ''Muséum national d'Histoire naturelle''. In 1841 he obtained the chair of zoology and comparative anatomy at the Faculty of Sciences in Montpellier, of which he was in 1856 appointed dean. In 1848–1852 appeared his important work ''Zoologie et paléontologie françaises'', supplementary to the palaeontological publications of Georges Cuvier and Henri Marie Ducrotay de Blainville; of this a second and greatly improved edition was issued in 1859. In 1865 he accepted the professorship of zoology at the Sorbonne, vacant through the death of Louis Pierre Gratiolet; this post he left in 1868 for the chair of comparative anatomy a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthracotherium
''Anthracotherium'', from Ancient Greek ἄνθραξ (''ánthrax''), meaning "coal", and θηρίον (''theríon''), meaning "beast", is an extinct genus of artiodactyls characterized by having 44 teeth, with five semi-crescentic cusps on the crowns of the upper molars. The genus ranged from the middle Eocene period until the early Miocene, having a distribution throughout Eurasia probably even reaching South East Asia (Kalimantan and West Timor). Material subjectively assigned to ''Anthracotherium'' from Pakistan suggests the last species died out soon after the start of the Miocene. Description The genus typifies the family Anthracotheriidae, if only because it is the most thoroughly studied. In many respects, especially the anatomy of the lower jaw, ''Anthracotherium'', as with the other members of the family, is allied to the hippopotamus, of which it is probably an ancestral form. The Anthracotheres, together with the hippos, are grouped with the cetaceans in the clade W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachydermata
Pachydermata (meaning 'thick skin', from the Greek , and ) is an obsolete order of mammals described by Gottlieb Storr, Georges Cuvier, and others, at one time recognized by many systematists. The term ' is commonly used to describe elephants, rhinoceroses, hippopotamuses and tapirs. The grouping was determined to be artificial as a biological classification due to genetic studies. Description Pachydermata is an obsolete order of mammals described by Gottlieb Storr, Georges Cuvier, and others, at one time recognized by many systematists. The grouping is polyphyletic, so the order is no longer in use as a biological classification. Outside strict biological classification, the related term ' is commonly used to describe elephants, rhinoceroses, hippopotamuses and tapirs. Cuvier himself defined ''Pachydermata'' as "animals with hoofs, non ruminants", whereas Storr had described it as "mammals with hoofs with more than two toes". The classification ''Pachydermata'' included t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quercy Phosphorites Formation
The Quercy Phosphorites Formation (French language, French: ''Phosphorites du Quercy''; ) is a Formation (geology), geologic formation and lagerstätte in Occitania (administrative region), Occitanie, southern France. It preserves fossils dated to the Paleogene Period (geology), period (Bartonian, latest Bartonian to Late Oligocene),Quercy Phosphorites Formation at Fossilworks.orgPhosphorites du Quercy Formation at Fossilworks.org or MP16 to MP28 zones of the Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
