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Pezosiren
''Pezosiren portelli'', also known as the "walking manatee", is a basal sirenian from the early Eocene of Jamaica, 50 million years ago. The type specimen is represented by a Jamaican fossil skeleton, described in 2001 by Daryl Domning, a marine mammal paleontologist at Howard University in Washington, DC. It is believed to have had a hippopotamus-like amphibious lifestyle, and is considered a transitional form between land and sea mammals:.Prothero, Donald R. 2007. ''Evolution: What the Fossils Say and Why It Matters''. With original illustrations by Carl Buell. New York, Columbia University Press. Discovery In the 1990s, vertebrate fossils were found in lagoon deposits at Seven Rivers in Jamaica by Daryl Domning and colleagues. The site is rich in fossils, and yielded hundreds of bones of mainly aquatic vertebrates, a primitive rhinoceros, and possibly a primate. In 2001, Domning named ''Pezosiren portelli'' based on sirenian bones found at Seven Rivers. The Seven Rivers sit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pezosiren Clean
''Pezosiren portelli'', also known as the "walking manatee", is a Basal (phylogenetics), basal sirenian from the early Eocene of Jamaica, 50 million years ago. The type specimen is represented by a Jamaican fossil skeleton, described in 2001 by Daryl Domning, a marine mammal paleontologist at Howard University in Washington, DC. It is believed to have had a hippopotamus-like amphibious lifestyle, and is considered a transitional form between land and sea mammals:.Prothero, Donald R. 2007. ''Evolution: What the Fossils Say and Why It Matters''. With original illustrations by Carl Buell. New York, Columbia University Press. Discovery In the 1990s, vertebrate fossils were found in lagoon deposits at Seven Rivers in Jamaica by Daryl Domning and colleagues. The site is rich in fossils, and yielded hundreds of bones of mainly aquatic vertebrates, a primitive rhinoceros, and possibly a primate. In 2001, Domning named ''Pezosiren portelli'' based on sirenian bones found at Seven Rivers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sobrarbesiren
''Sobrarbesiren'' (meaning "siren from Sobrarbe") is a genus of extinct sirenian that lived in the Eocene, about 47 million years ago. The type and only species is ''S. cardieli'', known from a multitude of specimens from the Spanish Pyrenees. ''Sobrarbesiren'' was a medium-sized animal, long and still retaining both pairs of limbs. Although initially thought to be amphibious, later studies instead suggest that they would have been fully aquatic and been selective sea grass browsers. Unlike modern dugongs and manatees, they likely lacked a tail fluke, although it would have appeared horizontally flattened. Discovery and naming ''Sobrarbesiren'' was discovered in the Castejón de Sobrarbe-41 locality (Sobrarbe Formation) in the Spanish Pyrenees, specifically the Huesca province. The locality dates to the Lutetian stage of the Eocene and preserved 300 individual siren fossils thought to belong to at least six individuals of different growth stages. The holotype specimen is complet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prorastomus
''Prorastomus sirenoides'' is an extinct species of primitive sirenian that lived during the Eocene Epoch 40 million years ago in Jamaica. Taxonomy The generic name ''Prorastomus'', a combination of Greek (''prōra''), prow, and (''stoma''), mouth, refers to the lower jaw of the animal "resembling the prow of a wherry". The genus name ''Prorastomus'' comes from Greek ''prora'' meaning "prow" and Latin ''stomus'' meaning "mouth." In 1892, naturalist Richard Lydekker respelled it as ''Prorastoma'' with a feminine ending, however this was unjustified as ''stomus'' is masculine in Latin. ''Prorastomus'' is one of two genera of the family Prorastomidae, the other '' Pezosiren''. These two species are the oldest sirenians, dating to the Eocene. The first specimen was described by paleontologist Sir Richard Owen in 1855, and, being found in Jamaica in the Yellow Limestone Group, pointed to the origin of Sirenia as being in the New World rather than the Old World as was previously ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sirenian
The Sirenia (), commonly referred to as sea-cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The Sirenia currently comprise two distinct families: Dugongidae (the dugong and the now extinct Steller's sea cow) and Trichechidae (manatees, namely the Amazonian manatee, West Indian manatee, and West African manatee) with a total of four species. The Protosirenidae (Eocene sirenians) and Prorastomidae (terrestrial sirenians) families are extinct. Sirenians are classified in the clade Paenungulata, alongside the elephants and the hyraxes, and evolved in the Eocene 50 million years ago (mya). The Dugongidae diverged from the Trichechidae in the late Eocene or early Oligocene (30–35 mya). Sirenians grow to between in length and in weight. The historic Steller's sea cow was the largest known sirenian to have lived, and could reach lengths of and weights of . Sirenians have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution Of Sirenians
Sirenia is the order of placental mammals which comprises modern "sea cows" (manatees and the Dugong) and their extinct relatives. They are the only extant herbivorous marine mammals and the only group of herbivorous mammals to have become completely aquatic. Sirenians are thought to have a 50-million-year-old fossil record (early Eocene-recent). They attained modest diversity during the Oligocene and Miocene, but have since declined as a result of climatic cooling, oceanographic changes, and human interference. Two genera and four species are extant: ''Trichechus'', which includes the three species of manatee that live along the Atlantic coasts and in rivers and coastlines of the Americas and western Africa, and ''Dugong'', which is found in the Indian and Pacific oceans. Origins Sirenians, along with Proboscidea (elephants), group together with the extinct Desmostylia and likely the extinct Embrithopoda to form the Tethytheria. Tethytheria is thought to have evolved f ... [...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] |
Society Of Vertebrate Paleontology
The Society of Vertebrate Paleontology (SVP) is a professional organization that was founded in the United States in 1940 to advance the science of vertebrate paleontology around the world. Mission and Activities SVP has about 2,300 members internationally and holds annual scientific conferences in North America and elsewhere. It is organized for educational and scientific purposes with a mission to "advance the science of vertebrate paleontology and to serve the common interests and facilitate the cooperation of all persons concerned with the history, evolution, comparative anatomy, and taxonomy of vertebrate animals, as well as field occurrence, collection, and study of fossil vertebrates and the stratigraphy of the beds in which they are found." SVP is also concerned with the conservation and preservation of fossil sites. SVP publications include the ''Journal of Vertebrate Paleontology'', the ''SVP Memoir Series'', the ''News Bulletin'', the''Bibliography of Fossil Vertebrates' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 2001
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Placental Genera
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. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transitional Fossils
A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. Therefore, it cannot be assumed that transitional fossils are direct ancestors of more recent groups, though they are frequently used as models for such ancestors. In 1859, when Charles Darwin's ''On the Origin of Species'' was first published, the fossil record was poorly known. Darwin described the perceived lack of transitional fossils as "the most obvious and gravest objection which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene Sirenians
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic 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 13C in the atmosphere was exceptionally low in comparison with the more common isotope 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 Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Mammals Of North America
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognised as a formal stratigraphic term, 'Tertiary' is still widely found in earth science literature and remains in informal use. Paleogene is often abbreviated "Pg" (but the United States Geological Survey uses the abbreviation PE for the Paleogene on the Survey's geologic maps). During the Paleogene, mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
