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Perucetus
''Perucetus'' is an extinct genus of an early whale from Peru that lived during the Bartonian age of the middle Eocene. ''Perucetus'' is the largest Eocene whale, with length estimates varying from to . It was initially claimed to have rivaled or exceeded the modern blue whale in weight, partly due to the incredibly thick and dense bones this animal possessed, coupled with its already great size, but subsequent studies argued that it was significantly lighter. The ecology of ''Perucetus'' also remains largely mysterious. Based on the fossils, it was likely a slow-moving inhabitant of shallow waters. Its diet can only be speculated, but one suggestion proposes that it may have fed on benthic animals like crustaceans and molluscs living on the ocean floor. Only a single species is currently known, ''P. colossus''. History and naming ''Perucetus'' is known from a variety of bones; namely, thirteen vertebrae, four ribs, and some parts of the pelvic region. All bones are from the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Whale
The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. Four subspecies are recognized: ''B. m. musculus'' in the North Atlantic and North Pacific, ''B. m. intermedia'' in the Southern Ocean, ''B. m. brevicauda'' (the pygmy blue whale) in the Indian Ocean and South Pacific Ocean, and ''B. m. indica'' in the Northern Indian Ocean. There is a population in the waters off Chile that may constitute a fifth subspecies. In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics. There is also evidence of year-round residencies, and partial or age/sex-based migration. Blue whales are filter feeders; their diet consists almost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2023 In Paleomammalogy
This article records new taxa of fossil mammals of every kind binomial nomenclature, described during the year 2023, as well as other significant discoveries and events related to paleontology of mammals which occurred in 2023. Afrotherians Proboscideans Proboscidean research * Review of the systematics and evolutionary history of African proboscideans is published by William J. Sanders, Sanders (2023). * A study on the evolution of teeth of proboscideans from East Africa over the past 26 million years is published by Saarinen & Lister (2023), who find evidence of ratchet-like mode of evolution, with periods of rapid increase in hypsodonty and Molar (tooth)#Lophodont, loph count (probably related to episodes of increase of aridity) alternating with longer periods of relative stasis rather than reversal of these traits. * Choudhary ''et al.'' (2023) report the first discovery of the fossil material of a Mammutidae, mammutid (cf. ''Zygolophodon'') from the Upper Miocene deposits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynthiacetus
''Cynthiacetus'' is an extinct genus of basilosaurid early whale that lived during the Late Eocene (Bartonian-Priabonian, .) Specimens have been found in the southeastern United States and Peru ( Otuma Formation). Discovery and naming ''Cynthiacetus'' was named after the town of Cynthia, Mississippi, close to where the type specimen for the species ''C. maxwelli'' was discovered. Description The skull of ''C. maxwelli'' was similar in size and morphology to that of ''Basilosaurus cetoides'', but ''Cynthiacetus'' lacked the elongated vertebrae of ''Basilosaurus''. erected the genus to avoid the ''nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...'' '' Pontogeneus'' (which was based on poorly described and now vanished specimens). ''Cynthiacetus'' was small ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basilosaurus
''Basilosaurus'' (meaning "king lizard") is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). First described in 1834, it was the first archaeocete and prehistoric whale known to science. Fossils attributed to the type species ''B. cetoides'' were discovered in the southeastern United States. They were originally thought to be of a giant reptile, hence the suffix "-saurus", Ancient Greek for "lizard". The animal was later found to be an early marine mammal, prompting attempts at renaming the creature, which failed as the rules of zoological nomenclature dictate using the original name given. The second species named in 1904, ''B. isis'', lived in the region currently known as the Mediterranean Sea, with fossils found in North Africa and Jordan. ''Basilosaurus'' is thought to have been one of the largest animals of the Paleogene, with the type species ''B. cetoides'' measuring around long and we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bartonian
The Bartonian is, in the International Commission on Stratigraphy's (ICS) geologic time scale, a stage or age in the middle of the Eocene Epoch or Series. The Bartonian Age spans the time between . It is preceded by the Lutetian and is followed by the Priabonian Age. Stratigraphic definition The Bartonian Stage was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1857. The name derives from the Barton Group, a lithostratigraphic unit from the south English Hampshire Basin, which in turn derived its name from the local coastal village Barton-on-Sea (part of New Milton) in southern England. The distinction between group and stage was made in the second part of the 20th century, when stratigraphers saw the need to distinguish between litho- and chronostratigraphy. The base of the Bartonian is at the first appearance of the calcareous nanoplankton species ''Reticulofenestra reticulata''. In 2009, an official reference profile (GSSP) for the base of the Bartonian had not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medullary Cavity
The medullary cavity (''medulla'', innermost part) is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow (adipose tissue) is stored; hence, the medullary cavity is also known as the marrow cavity. Located in the main shaft of a long bone (diaphysis) (consisting mostly of spongy bone), the medullary cavity has walls composed of compact bone (cancellous bone) and is lined with a thin, vascular membrane (endosteum). This area is involved in the formation of red blood cells and white blood cells, and the calcium supply for bird eggshells. The area has been detected in fossil bones despite the fossilization process. Intramedullary is a medical term meaning the inside of a bone. Examples include intramedullary rods used to treat bone fractures in orthopedic surgery and intramedullary tumors occurring in some forms of cancer or benign tumors such as an enchondroma Enchondroma is a type of benign bone tumor belonging to the group of cartilage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathology
Pathology is the study of disease. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatment, the term is often used in a narrower fashion to refer to processes and tests that fall within the contemporary medical field of "general pathology", an area that includes a number of distinct but inter-related medical specialties that diagnose disease, mostly through analysis of tissue (biology), tissue and human cell samples. Idiomatically, "a pathology" may also refer to the predicted or actual progression of particular diseases (as in the statement "the many different forms of cancer have diverse pathologies", in which case a more proper choice of word would be "Pathophysiology, pathophysiologies"). The suffix ''pathy'' is sometimes used to indicate a state of disease in cases of both physical ailment (as in cardiomyopathy) and psych ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachycetinae
Pachycetinae is an extinct subfamily of Basilosauridae, basilosaurid cetaceans that lived during the middle Eocene. The best-dated remains stem from Bartonian strata, but some finds suggest that they could have first appeared during the Lutetian and may have survived until the Priabonian. Fossils of pachycetines are chiefly known from the southern United States, Ukraine, Morocco and Germany, among others. They differ from other basilosaurids in having pachyostotic and osteosclerotic vertebrae and ribs, making them denser and heavier by comparison. Based on this it has been suggested that these whales lived in shallow waters and that these thickened bones act as a buoyancy control as seen in sirenians. Analysis of the teeth suggests that pachycetines had a varying diet, with the robust teeth of the larger ''Pachycetus'' indicating that it possibly fed on sharks, whereas the more gracile teeth of ''Antaecetus'' suggest a diet of smaller prey items. The clade currently only includes t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
