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Macrorhineura Skinneri
''Macrorhineura'' is an extinct genus of rhineurid amphisbaenian or worm lizard, including the type and only species ''Macrorhineura skinneri'', named in 1970 on the basis of the front half of a skull from the Early Miocene Sharps Formation in Wounded Knee, South Dakota. Although the skull is incomplete, features such as a pointed, shovel-shaped snout indicate that it belongs to the family Rhineuridae. Within Rhineuridae, ''Macrorhineura'' is most closely related to '' Ototriton'' and '' Hyporhina'', two genera from the Eocene and Oligocene of Colorado and Wyoming, based on the shared feature of equally sized dentary teeth in the lower jaw. Together they form a clade or evolutionary grouping of mid-continental rhineurids, which became isolated from a more western clade of rhineurids that includes '' Dyticonastis'' and '' Spathorhynchus''. Rhineurids were relatively common across much of North America during the Paleogene, but their range contracted in the Neogene The Neogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Miocene
The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to 15.97 ± 0.05 Ma (million years ago). It was preceded by the Oligocene epoch. As the climate started to get cooler, the landscape started to change. New mammals evolved to replace the extinct animals of the Oligocene epoch. The first members of the hyena and weasel family started to evolve to replace the extinct ''Hyaenodon'', entelodonts and bear-dogs. The chalicotheres survived the Oligocene epoch. A new genus of entelodont called ''Daeodon'' evolved in order to adapt to the new habitats and hunt the new prey animals of the Early Miocene epoch; it quickly became the top predator of North America. But it became extinct due to competition from ''Amphicyon'', a newcomer from Eurasia. ''Amphicyon'' bested ''Daeodon'' because the bear-dog's la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentary Bone
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone is the skull's only movable, posable bone, sharing joints with the cranium's temporal bones. The mandible hosts the lower teeth (their depth delineated by the alveolar process). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels. Amongst other functions, the jawbone is essential for chewing food. Owing to the Neolithic advent of agriculture (), human jaws evolved to be smaller. Although it is the strongest bone of the facial skeleton, the mandible tends to deform in old age; it is also subject to fracturing. Surgery allows for the removal of jawbone fragments (or its entirety) as well as regenerative methods. Additionally, the bone is of great forensic significance. Structure In hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene Reptiles Of North America
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene followed the Oligocene and preceded the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by distinct global events but by regionally defined transitions from the warmer Oligocene to the cooler Pliocene Epoch. During the Early Miocene, Afro-Arabia collided with Eurasia, severing the connection between the Mediterranean and Indian Oceans, and allowing the interchange of fauna between Eurasia and Africa, including the dispersal of proboscideans and hominoids into Eurasia. During the late Miocene, the connections between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphisbaenia
Amphisbaenia (called amphisbaenians or worm lizards) is a group of typically legless lizards, comprising over 200 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes. As many species have a pink body and scales arranged in rings, they have a superficial resemblance to earthworms. While the genus '' Bipes'' retains forelimbs, all other genera are limbless. Phylogenetic studies suggest that they are nested within Lacertoidea, closely related to the lizard family Lacertidae. Amphisbaenians are widely distributed, occurring in North America, Europe, Africa, South America, Western Asia and the Caribbean. Most species are less than long. Description 200px, left, Close-up of the head of'' Rhineura'' Despite a superficial resemblance to some primitive snakes, amphisbaenians have many unique features that distinguish them from other reptiles. Internally, their right lung is reduced in size to fit their narrow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhineura Floridana
''Rhineura floridana'', known commonly as the Florida worm lizard, graveyard snake, or thunderworm, is a species of amphisbaenian in the family Rhineuridae. The species is the only extant member of the genus ''Rhineura'', and is found primarily in Florida but has been recorded in Lanier County, Georgia. There are no subspecies that are recognized as being valid. Description ''R. floridana'' varies in total length (including tail) from . The head has a shovel-like snout that projects forward past the lower jaws, which is used for burrowing. The eyes are highly reduced and not visible externally. The limbs are absent and, as in other Amphisbaenia, the body is covered by scales arranged in rings giving the animal a worm-like appearance. Habitat The preferred natural habitats of ''R. floridana'' are forest and shrubland. More specifically, in xeric and mesic hammocks around northeastern and central Florida. Southern populations have been shown to prefer xeric hammocks. Behavior '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neogene
The Neogene ( ,) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period million years ago. It is the second period of the Cenozoic and the eleventh period of the Phanerozoic. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868). The earlier term Tertiary Period was used to define the span of time now covered by Paleogene and Neogene and, despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use. During this period, mammals and birds continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first human ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene
The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the first period of the Cenozoic Era, the tenth period of the Phanerozoic and is divided into the Paleocene, Eocene, and Oligocene epochs. The earlier term Tertiary Period was used to define the time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use. Paleogene is often abbreviated "Pg", although the United States Geological Survey uses the abbreviation "" for the Paleogene on the Survey's geologic maps. Much of the world's modern vertebrate diversity originated in a rapid surge of diversification in the early Paleogene, as survivors of the Cretaceous–Paleogene extinction event took advantage of empty ecolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spathorhynchus
''Spathorhynchus'' is an extinct genus of amphisbaenians or worm lizards that existed from the Middle Eocene to the Early Oligocene in what is now Wyoming. It includes two species, the type species ''S. fossorium'', named in 1973 from the Middle Eocene Bridger and Wind River Formations, and the species ''S. natronicus'', named in 1977 from the Lower Oligocene White River Formation. ''Spathorhynchus'' belongs to the family Rhineuridae, which includes many other extinct species that ranged across North America at various times in the Cenozoic but only has one surviving member, ''Rhineura floridana'', from Florida. ''Spathorhynchus'' differs from all other rhineurids except '' Dyticonastis'' from the Late Oligocene-Early Miocene of Oregon in having a slightly widened, spatula-shaped snout tip with a low angle of about 30 degrees. The two taxa may be closely related, having evolved in isolation in western North America after the formation of the Rocky Mountains The Rocky Mountai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyticonastis
''Dyticonastis'' is an extinct genus of amphisbaenians, or worm lizards, that includes a single species, ''Dyticonastis rensbergeri'', that lived during the late Oligocene and early Miocene in what is now Oregon. Fossils of the species come from the John Day Formation. It belongs to Rhineuridae, a family that includes many other extinct North American amphisbaenians but only one living species, ''Rhineura floridana'', from Florida. ''Dyticonastis rensbergeri'' occurs the farthest west of all rhineurid species. Like all rhineurids, ''Dyticonastis'' has a shovel-like snout adapted for burrowing underground, but it differs from most other members of the group in having a relatively shallow angle to its snout wedge (about 30 degrees) and in having a widened snout tip. The only other rhineurids that share these features are species of the genus ''Spathorhynchus'', which lived from the Middle Eocene to the Early Oligocene in what is now Wyoming. A 2007, phylogenetic analysis of amphisba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population, or a species (extinct or Extant taxon, extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed ''monophyletic'' (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming Taxon, taxa that are not clades; that is, taxa that are not Monophyly, monophyletic. Some of the relationships between organisms that the molecul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from Ancient Greek (''olígos'') 'few' and (''kainós'') 'new', and refers to the sparsity of Neontology, extant forms of Mollusca, molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major chang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
