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Romaleodelphis
''Romaleodelphis'' is a genus of extinct archaic toothed whale from the Early Miocene Ebelsberg Formation of Austria. It had long and slender jaws and homodont teeth and roamed the marine waters of the Central Paratethys that once covered much of Europe. Phylogenetic analysis has shown that ''Romaleodelphis'' is most closely related to other odotontocetes previously grouped together as the "'' Chilcacetus'' clade, now a paraphyletic grade basal to true dolphins and beaked whales. The inner ear of ''Romaleodelphis'' shows that it was capable of hearing hearing narrow-band high frequency sounds, an ability it convergently evolved with several modern types of whales. It is possible that this was a useful tool in evading other predatory whales, though some recent research suggests that it may have also been an early step in the development of the cetacean biosonar. History and naming The holotype skull of ''Romaleodelphis'' was discovered in 1980 in the sediments of the Ebelsberg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebelsberg Formation
The Ebelsberg Formation is a geologic formation in Austria. The section exposed near the town of Pucking are considered to be a Konservat-Lagerstätte. It preserves fossils dated to the Aquitanian age of the Miocene epoch. History of study The marine deposits of the Ebelsberg Formation near Pucking were exposed in the 1980s when a hydroelectric power plant was built across the river Traun close to Linz, the capital of Upper Austria. Initial studies considered the Ebelsberg Formation to be Oligocene in age, specifically dating it to the Chattian (Late Oligocene). However, more recent studies have shown this to be false, instead proposing a younger age corresponding with the Aquitanian stage of the Miocene. Locally, this would correspond to the Upper Egerian, making the outcrops about 22 million years old. Environment During the Aquitanian this part of Austria was covered by the extensive Paratethys sea, with the Ebelsberg Formation specifically having been formed in the outer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paratethys
The Paratethys sea, Paratethys ocean, Paratethys realm or just Paratethys (meaning "beside Tethys"), was a large shallow inland sea that covered much of mainland Europe and parts of western Asia during the middle to late Cenozoic, from the late Paleogene to the late Neogene, and is regarded as the largest inland sea in history. At its greatest extent, it stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia. Paratethys formed about 34 Mya (million years ago) at the beginning of the Oligocene epoch, when the northern region of the Tethys Ocean (Peri-Tethys) was separated from the Mediterranean region of the Tethys realm due to the formation of the Alps, Carpathians, Dinarides, Taurus and Elburz mountains. Paratethys was at times reconnected with the Tethys or its successors (the Mediterranean Sea or the Indian Ocean) during the Oligocene and the early and middle Miocene times, but at the onset of the late Miocene epoch, the tecton ... [...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] |
Macrodelphinus
''Macrodelphinus'' is an extinct genus of primitive odontocete known from Early Miocene marine deposits in California. Biology ''Macrodelphinus'' was an orca-sized odontocete similar to members of Eurhinodelphinidae in having a swordfish-like rostrum and upper jaw. Because of its size, and inch-long teeth, it is believed to have been an apex predator. Classification ''Macrodelphinus'' is known from a fragmentary skull from the Early Miocene Jewett Sand Formation of Kern County Kern County is a county (United States), county located in the U.S. state of California. As of the 2020 United States census, 2020 census, the population was 909,235. Its county seat is Bakersfield, California, Bakersfield. Kern County compris ..., southern California. Although often classified as a member of Eurhinodelphinidae, the cladistic analysis of '' Chilcacetus'' recovers it outside Eurhinodelphinidae, less advanced than '' Eoplatanista''. The Miocene species ''"Champsodelphis" valenciennesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is Cladogram#Homoplasies, homoplasy. The recurrent evolution of flight is a classic example, as flying pterygota, insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas ''homology (biology), homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different trai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kogiidae
Kogiidae is a family comprising at least two extant species of Cetacea, the pygmy (''Kogia breviceps)'' and dwarf (''K. sima)'' sperm whales. As their common names suggest, they somewhat resemble sperm whales, with squared heads and small lower jaws, but are much smaller, with much shorter skulls and more notable dorsal fins than sperm whales. Kogiids are also characterized by a "false gill slit" behind their eyes. A number of extinct genera have been named. Taxonomy There is some amount of uncertainty over if Kogiidae belongs in the sperm whale family. Research still suggests a close relationship between Kogiidae and sperm whales using mitochondrial DNA, which supports Kogiidae as part of the sperm whale family. This relationship is supported by similarities of the anatomical structures in the head, responsible for sound production, in particular the presence of a spermaceti organ. Other phylogenetic research raises further questions over a potential relationship between kog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porpoises
Porpoises () are small dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and belugas than to the true dolphins. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins (e.g. Hector's dolphin) also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates. Porpoises range in size from the vaquita, at in length and in weight, to the Dall's porpoise, at and . Several species exhibit sexual dimorphism in that the females are larger than males. They have streamlined bodies and two limbs that are modified into flippers. Porpoises use echolocation as their primary sensory system. Some species are well adapt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principal Component Analysis
Principal component analysis (PCA) is a linear dimensionality reduction technique with applications in exploratory data analysis, visualization and data preprocessing. The data is linearly transformed onto a new coordinate system such that the directions (principal components) capturing the largest variation in the data can be easily identified. The principal components of a collection of points in a real coordinate space are a sequence of p unit vectors, where the i-th vector is the direction of a line that best fits the data while being orthogonal to the first i-1 vectors. Here, a best-fitting line is defined as one that minimizes the average squared perpendicular distance from the points to the line. These directions (i.e., principal components) constitute an orthonormal basis in which different individual dimensions of the data are linearly uncorrelated. Many studies use the first two principal components in order to plot the data in two dimensions and to visually identi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squaloziphius
''Squaloziphius'' is an extinct genus of odontocete cetacean from the Early Miocene (Aquitanian age, Aquitanian)-aged Clallam Formation of Washington (state), Washington state. Systematics It was originally classified as the most primitive beaked whale, being placed in a separate subfamily, Squaloziphiinae, (followed by Fordyce and Muizon 2001) but later authors have placed it outside Ziphiidae as either Odontoceti ''incertae sedis'' or closely related to Ziphiidae. The description of the archaic odontocete ''Yaquinacetus'' demonstrated that ''Squaloziphius'' was by no means part of Ziphiidae and that these two taxa are more primitive than crown Odontoceti, necessitating elevation of Squaloziphiinae to full familial status, as Squaloziphiidae. Olivier Lambert, Stephen J. Godfrey & Erich M. G. Fitzgerald (2018) Yaquinacetus meadi, a new latest Oligocene–early Miocene dolphin (Cetacea, Odontoceti, Squaloziphiidae, fam. nov.) from the Nye Mudstone (Oregon, U.S.A.), Journal of Vert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
