|
Pelycodus Jarrovii
''Pelycodus'' (from Ancient Greek πέλυξ (pélux), “bowl” + ὀδούς (odoús), “tooth”) is an extinct genus of adapiform primate that lived during the early Eocene (Wasatchian) period in Europe and North America, particularly Wyoming and New Mexico. It is very closely related to ''Cantius'' and may even be its subgenus. It may also have given rise to the Middle Eocene Uintan primate '' Hesperolemur'', although this is controversial. From mass estimates based on the first molar, the two species, ''P. jarrovii'' and ''P. danielsae'', weighed 4.5 kg and 6.3 kg respectively and were frugivores with an arboreal, quadrupedal locomotion. History ''Pelycodus'' was first identified as ''Prototomus jarrovii'' by Cope in 1874, who pronounced it a rare inhabitant of both Wyoming and New Mexico. Over the next hundred years, approximately a dozen species were added, most more primitive dentally than the now renamed '' Pelycodus jarrovii''.Fleagle, J. G. 1999. ''Primat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). 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'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. 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 isotope Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notharctinae
Notharctinae is an extinct subfamily of primates that were common in North America during the early and middle Eocene (55-34 million years ago). The six genera that make up the group (''Cantius'', '' Pelycodus'', ''Copelemur'', '' Hesperolemur'', '' Notharctus'', and '' Smilodectes'') contain species that are among the most primitive of the adapiform group, which is one of the most primitive groups of primates. The evolutionary history of this subfamily has been comparatively well documented and has been used to argue for evolutionary gradualism. Though it is generally accepted that adapiforms gave rise to modern day lemurs and lorises, it is not currently known which branch of Adapiformes these living species are most closely related to. Notharctines became extinct in the middle Eocene, most likely because of a combination of factors including climatic change and competition with other North American primates. Taxonomic diversity Notharctinae is one of the two subfamilies, alon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Strepsirrhines
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing house specializing in monographs and scholarly journals. Most are nonprofit organizations and an integral component of a large research university. They publish work that has been reviewed by schola ... in the world. It is also the King's Printer. Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. It became part of Cambridge University Press & Assessment, following a merger with Cambridge Assessment in 2021. With a global sales presence, publishing hubs, and offices in more than 40 Country, countries, it publishes over 50,000 titles by authors from over 100 countries. Its publishing includes more than 380 academic journals, monographs, reference works, school and uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gradualism
Gradualism, from the Latin ''gradus'' ("step"), is a hypothesis, a theory or a tenet assuming that change comes about gradually or that variation is gradual in nature and happens over time as opposed to in large steps. Uniformitarianism, incrementalism, and reformism are similar concepts. Geology and biology In the natural sciences, gradualism is the theory which holds that profound change is the cumulative product of slow but continuous processes, often contrasted with catastrophism. The theory was proposed in 1795 by James Hutton, a Scottish geologist, and was later incorporated into Charles Lyell's theory of uniformitarianism. Tenets from both theories were applied to biology and formed the basis of early evolutionary theory. Charles Darwin was influenced by Lyell's ''Principles of Geology'', which explained both uniformitarian methodology and theory. Using uniformitarianism, which states that one cannot make an appeal to any force or phenomenon which cannot presently be obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smilodectes
''Smilodectes'' is a genus of adapiform primate that lived in North America during the middle Eocene. It possesses a post-orbital bar and grasping thumbs and toes. ''Smilodectes'' has a small cranium size and the foramen magnum was located at the back of the skull, on the occipital bone. Named species There are three named species: ''Smilodectes gracilis'', ''Smilodectes gingerichi'' and ''Smilodectes mcgrewi''. ''Smilodectes gracilis'' ''Smilodectes gracilis'' was an adapiformes primate from the early Eocene, some 55 million years ago. ''S. gracilis'' was found on the land mass of North America and based on its dental morphology, ''S. gracilis'' was a folivore. ''S. gracilis'' had a dental formula of and had a relatively short snout, with rounded frontal bone as compared to other nothactines. This species lacked symphyseal fusion and this species of primate had comparatively reduced olfactory bulbs and a more expanded visual cortex. This suggests that ''S. gracilis'' w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notharctus
''Notharctus'' ("false bear", from the Ancient Greek nothos (νόθος), "illegitimate", and arktos (ἄρκτος), "bear") is a genus of adapiform primate that lived in North America and Europe during the late to middle Eocene. The body form of ''Notharctus'' is similar to that of modern rats. Its fingers were elongated for clamping onto branches, including the development of a thumb The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb .... Its spine is flexible and the animal was about in length, excluding the long tail. There were at least four different ''Notharctus'' species. Fossils from at least seven other potential species have also been discovered. References Bibliography * External links Mikko's Phylogeny Archive {{Taxonbar, from=Q2086632 Prehistoric stre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or 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 taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Bone
The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of the lacrimal bone function in the process of lacrimation or crying. Specifically, the lacrimal bone helps form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of the bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears or lacrimal fluid, from the lacrimal glands, collect in this sac during excessive lacrimation. The fluid then flows through the nasolacrimal duct and into the nasopharynx. This drainage results in what is commonly referred to a runny nose during excessive crying or tear production. Injury or fracture of the lacrimal bone can result in posttraumatic obstruction of the lacrimal pathways. Structure Lateral or orbital surface The lateral or orbital surface i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
