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Tiucetus
''Tiucetus'' is an extinct genus of cetotheriid baleen whale known from the Late Miocene Pisco Formation of Peru. Description ''Tiucetus'' is distinct from other cetotheriids in having a squamosal cleft; from eomysticetids in having comparatively short nasals, a more anteriorly projected supraoccipital and parietal, and a tympanic bulla that is rotated so that the inner posterior prominence faces dorsally.Marx, F., Lambert, O., de Muizon, C. 2017A new Miocene baleen whale from Peru deciphers the dawn of cetotheriids.Royal Society Open Science. doi: 10.1098/rsos.170560 Classification ''Tiucetus'' falls basally in Cetotheriidae, less derived than ''Joumocetus'' and ''Cephalotropis''. Palaeogeography Other marine mammals found in the Pisco Formation include another cetotheriid, ''Piscobalaena'', the odd dolphin ''Odobenocetops'', the killer sperm whale ''Acrophyseter'', the long-necked seal ''Acrophoca'', and aquatic sloth ''Thalassocnus ''Thalassocnus'' is an extinct gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baleen Whales
Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae (right and bowhead whales), Balaenopteridae (rorquals and the gray whale), and Cetotheriidae (the pygmy right whale). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychids, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago. Baleen whales range in size from the and pygmy right whale to the and blue whale, the largest known animal to have ever existed. They are sexually dimorphic. Baleen whales can have streamlined or large bodies, depending on the fee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baleen Whale
Baleen whales ( systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea ( whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae (right and bowhead whales), Balaenopteridae ( rorquals and the gray whale), and Cetotheriidae (the pygmy right whale). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychids, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago. Baleen whales range in size from the and pygmy right whale to the and blue whale, the largest known animal to have ever existed. They are sexually dimorphic. Baleen whales can have streamlined or large bodies, de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tortonian
The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tortonian roughly overlaps with the regional Pannonian Stage of the Paratethys timescale of Central Europe. It also overlaps the upper Astaracian, Vallesian and lower Turolian European land mammal ages, the upper Clarendonian and lower Hemphillian North American land mammal ages and the upper Chasicoan and lower Huayquerian South American land mammal ages. Definition The Tortonian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian city of Tortona in the region Piedmont. The base of the Tortonian Stage is at the last common appearance of calcareous nanoplankton ''Discoaster kugleri'' and planktonic foram '' Globigerinoides subquadratus''. It is also associated with the short normal pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrophoca
''Acrophoca longirostris'', sometimes called the swan-necked seal, is an extinct genus of Late Miocene pinniped. It was thought to have been the ancestor of the modern leopard seal, however it is now thought to be a species of monk seal. Taxonomy The fossils of ''A. longirostris'' have been discovered in the Pisco Formation of Peru and the Bahía Inglesa Formation of Chile. When it was first described in 1981, it was thought to have been closely related to the lobodontine seals which includes the modern day leopard seal (''Hydrurga leptonyx''), the crabeater seal (''Lobodon carcinophaga''), the Weddell seal (''Leptonychotes weddelli''), and the Ross seal (''Ommatophoca rossii''). However, it is now thought to be a basal species of monk seal of the subfamily Monachinae, closely related to the extinct seal '' Piscophoca''. Description ''Acrophoca'' was around long, and was not as well-adapted to swimming as its descendants, possessing less developed flippers and a less stream ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neogene Peru
The Neogene ( ), informally Upper Tertiary or Late Tertiary, 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 Mya. 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). During this period, mammals and birds continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans (''Homo habilis'') appeared in Africa near the end of the period. Some continental movements took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the warm ocean currents from the Pacific to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene Mammals Of South 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 is preceded by the Oligocene and is followed by 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 a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotypic Prehistoric Cetacean Genera
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. In contrast, an oligotypic taxon contains more than one but only a very few subordinate taxa. Examples Just as the term ''monotypic'' is used to describe a taxon including only one subdivision, the contained taxon can also be referred to as monotypic within the higher-level taxon, e.g. a genus monotypic within a family. Some examples of monotypic groups are: Plants * In the order Amborellales, there is only one family, Amborellaceae and there is only one genus, ''Amborella'', and in this genus there is only one species, namely ''Amborella trichopoda.'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalassocnus
''Thalassocnus'' is an extinct genus of semiaquatic ground sloths from the Miocene and Pliocene of the Pacific South American coast. It is monotypic within the subfamily Thalassocninae. The five species—''T. antiquus'', ''T. natans'', ''T. littoralis'', ''T. carolomartini'', and ''T. yuacensis''—represent a chronospecies, a population gradually adapting to marine life in one direct lineage. They are the only known aquatic sloths, but they may have also been adapted to a terrestrial lifestyle. They have been found in the Pisco Formation of Peru, the Tafna Formation of Argentina, and the Bahía Inglesa, Coquimbo, and Horcón formations of Chile. Thalassocninae has been placed in both the families Megatheriidae and Nothrotheriidae. ''Thalassocnus'' evolved several marine adaptations over the course of 4 million years, such as dense and heavy bones to counteract buoyancy, the internal nostrils migrating farther into the head to help with breathing while completely submerged, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sloth
Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their lives hanging upside down in the trees of the tropical rainforests of South America and Central America. Sloths are considered to be most closely related to anteaters, together making up the xenarthran order Pilosa. There are six extant sloth species in two genera – '' Bradypus'' (three–toed sloths) and '' Choloepus'' (two–toed sloths). Despite this traditional naming, all sloths have three toes on each rear limb-- although two-toed sloths have only two digits on each forelimb. The two groups of sloths are from different, distantly related families, and are thought to have evolved their morphology via parallel evolution from terrestrial ancestors. Besides the extant species, many species of ground sloths ranging up to the size of ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odobenocetops
''Odobenocetops'' () is an extinct genus of small toothed whale known from Peru and Chile. Its fossils are found in Neogene-aged marine strata dating from the Tortonian to the Zanclean. It had two tusks, and, in some fossils, one tusk was longer than the other. Phylogeny ''Odobenocetops'' can be identified as a cetacean based on several features unique to this order: # The presence of large air sinuses in the auditory region connected to large pterygoid sinuses. # The large supraorbital process of the frontal bone overhanging the orbital region. # Narial fossae opening dorsally (thought not at the apex of the skull like in other cetaceans.) # The absence of a true cribriform plate (a bony blade separating the nares). In ''Odobenocetops'', a group of foramina in this plate allows the passage of olfactory nerves connected to the small olfactory lobes in the brain. In other cetaceans, the olfactory nerves are similarly present but strongly reduced. # The elbow joint is immobile, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrophyseter
''Acrophyseter'' is a genus of extinct sperm whales that lived in the Late Miocene off the coast of Peru comprising two species: ''A. deinodon'' and ''A. robustus''. It is part of a group of macroraptorial sperm whales which all shared several features for the purpose of hunting large prey, such as deeply-rooted and thick teeth. ''Acrophyseter'' measured , making it the smallest raptorial sperm whale. Because of its short pointed snout, and its strong curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales. Discovery The genus ''Acrophyseter'' houses two species. The type species, ''A. deinodon'', was discovered in the Sud-Sacaco locality of the Pisco Formation in Peru, dating back to the Tortonian–Messinian stages of the Miocene around 8.5–6.7 million years ago (mya); the holotype specimen, MNHN SAS 1626, represents a mature individual and consists of a skull and jaw with most of the teeth intact. The second species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
