When did mososaurs live?
Mosasaur
Mosasaurs (from Latin "Mosa" meaning the 'Meuse river', and Greek σαύρος "sauros" meaning 'lizard') are an extinct group of large marine reptiles containing 38 genera in total. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Early Cretaceous. During the last 20 million years of the Cretaceous period (Turonian-Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.
Outline of dinosaurs
Dinosaurs – diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period (about 230 million years ago) until the end of the Cretaceous (66 million years ago), when the Cretaceous–Paleogene extinction event led to the extinction of all non-avian dinosaurs at the close of the Mesozoic era. The fossil record indicates that birds evolved within theropod dinosaurs during the Jurassic period. Some of them survived the Cretaceous–Paleogene extinction event, including the ancestors of all modern birds. Consequently, in modern classification systems, birds are considered dinosaurs—the only group which survived to the present day.
Pliosauridae
Pliosauridae is a family of plesiosaurian marine reptiles from the Earliest Jurassic to the early Late Cretaceous (Hettangian to Turonian stages) of Australia, Europe, North America and South America. Past the Turonian, they may have been replaced by the mosasaurs. It was formally named by Harry G. Seeley in 1874.
Mosasaurini
The Mosasaurini are a clade of derived mosasaurine mosasaurs. The tribe contains one of the largest known mosasaur species, "Mosasaurus hoffmannii" at over 12 meters in length, but it is notable that such a size is unusual within the tribe and even within the genus "Mosasaurus" itself. Other large mosasaurins are in a size range around 8 meters in length (such as "Plotosaurus", "Eremiasaurus" and "Mosasaurus conodon") whilst others are even smaller in a range of about 5–6 meters in length (such as "Mosasaurus beaugei" and "Mosasaurus missouriensis").
Gasosaurus
"Gasosarurus" lived during the mid-Jurassic period (Bathonian and/ or Callovian stages), around 164 million years ago. It coexisted with other mid-range theropods such as "Chuandongocoelurus" and "Kaijiangosaurus", two other dinosaurs found from the Lower Shaximiao Formation. These three taxa pertain to medium to large bodied theropods and are known from associated prostcranial skeletons. China, boasts the highest taxic diversity of Middle Jurassic theropods of all body sizes from anywhere in the world. Most Middle Jurassic theropods from china are 'medium-sized', as are the majority of Middle Jurassic theropods globally.
2010 in archosaur paleontology
The year 2010 in Archosaur paleontology was eventful. Archosaurs include the only living dinosaur group — birds — and the reptile crocodilians, plus all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosaur palaeontology is the scientific study of those animals, especially as they existed before the Holocene Epoch began about 11,700 years ago. The year 2010 in paleontology included various significant developments regarding archosaurs.
Mosasaurus
"Mosasaurus" was the first genus of mosasaurs to be named. The first remains known to science were a fragmentary skull from a chalk quarry in the St Pietersberg, a hill near Maastricht, the Netherlands, found in 1764 and collected by lieutenant Jean Baptiste Drouin in 1766. It was procured for the Teylers Museum at Haarlem in 1784 by Martinus van Marum, the first director of the museum, who published its description only in 1790. He considered it to be a species of "big breathing fish" ("Pisces cetacei", in other words: a whale). It is still part of the collection as TM 7424.
Dinosaur Walk Museum
Plesiosaurs: The Plesiosaurs were carnivorous aquatic reptiles. First appearing at the beginning of the Jurassic Period they thrived throughout the Cretaceous Period. They lived during the same time as the dinosaurs but were not dinosaurs, they are considered reptiles.
Ichthyosaur
Ichthyosaurs thrived during much of the Mesozoic era; based on fossil evidence, they first appeared around 250 million years ago (Ma) and at least one species survived until about 90 million years ago, into the Late Cretaceous. During the early Triassic period, ichthyosaurs evolved from a group of unidentified land reptiles that returned to the sea, in a development similar to how the mammalian land-dwelling ancestors of modern-day dolphins and whales returned to the sea millions of years later, which they gradually came to resemble in a case of convergent evolution. Ichthyosaurs were particularly abundant in the later Triassic and early Jurassic periods, until they were replaced as the top aquatic predators by another marine reptilian group, the Plesiosauria, in the later Jurassic and Cretaceous periods. In the Late Cretaceous, ichthyosaurs were hard hit by the Cenomanian-Turonian anoxic event. Their last lineage became extinct for unknown reasons.
Plioplatecarpinae
Plioplatecarpines were small to medium-sized mosasaurs that were comparatively fast and agile compared to mosasaurs of other subfamilies. The first plioplatecarpines appear in the Turonian and are among the oldest of mosasaurs, and the clade persists throughout the Maastrichtian, a period of approximately 24 million years. The subfamily was seemingly heavily affected during a poorly understood middle-Campanian mosasaur extinction event and its genera appear to have faced competition from mosasaurine mosasaurs during the Maastrichtian, leading to a decline in numbers and in diversity.
Marshosaurus
The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as "Camarasaurus"," Brachiosaurus", "Barosaurus", "Diplodocus", and "Apatosaurus". Dinosaurs that lived alongside "Marshosaurus" included the herbivorous ornithischians "Camptosaurus", "Dryosaurus", "Stegosaurus" and "Othnielosaurus". Predators in this paleoenvironment included the theropods "Saurophaganax", "Torvosaurus", "Ceratosaurus", "Stokesosaurus", "Ornitholestes" and "Allosaurus", which accounted for 70 to 75% of theropod specimens and was at the top trophic level of the Morrison food web. "Stegosaurus" is commonly found at the same sites as "Allosaurus", "Apatosaurus", "Camarasaurus", and "Diplodocus". Early mammals were present in this region, such as docodonts, multituberculates, symmetrodonts, and triconodonts. The flora of the period has been revealed by fossils of green algae, fungi, mosses, horsetails, cycads, ginkgoes, and several families of conifers. Vegetation varied from river-lining forests of tree ferns, and ferns (gallery forests), to fern savannas with occasional trees such as the "Araucaria"-like conifer "Brachyphyllum".
Massopoda
The Massopoda is a clade of sauropodomorph dinosaurs which lived during the Late Triassic to the Late Cretaceous periods. It was named by paleontologist Adam M. Yates of the University of the Witwatersrand in 2007. Massopoda is a stem-based taxon, defined as all animals more closely related to "Saltasaurus loricatus" than to "Plateosaurus engelhardti".
Yaguarasaurinae
The Yaguarasaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "yaguarasaurines" and have been recovered from North and South America and Europe. Three genera, "Yaguarasaurus", "Russellosaurus" and "Romeosaurus" are known."Yaguarasaurus" and "Russellosaurus" were previously considered part of the Tethysaurinae until they were grouped with "Romeosaurus" as yaguarasaurines.
Mudrock
Another noteworthy formation is the Morrison Formation. This area covers 1.5 million square miles, stretching from Montana to New Mexico in the United States. It is considered one of the world's most significant dinosaur burial grounds, and its many fossils can be found in museums around the world. This site includes dinosaur fossils from a few dinosaur species, including the "Allosaurus", "Diplodocus", "Stegosaurus", and "Brontosaurus". There are also lungfish, freshwater mollusks, ferns and conifers. This deposit was formed by a humid, tropical climate with lakes, swamps, and rivers, which deposited mudrock. Inevitably, mudrock preserved countless specimens from the late Jurassic, roughly 150 million years ago.
Mustelidae
The oldest fossil of the mustelids were dated at the end of the Oligocene to the beginning of the Miocene. “There is debate regarding which fossils from these epochs represent possible ancestral forms that led to Mustelidae and which fossils represent the first modern mustelids.”(Wund, M. 2005. "Mustelidae" (On-line), Animal Diversity Web.) From the fossil record we can see that Mustelids appeared in the late Oligocene period (33 mya) in Eurasia and migrated throughout the continents. The Mustelids inhabit every continent except Antarctica and Australia. The mustelids migrated all throughout the continents that were connected during the early Miocene. The Mustelids made their way to North and South America via the Bering land bridge.
Mosquito
The oldest known mosquito with an anatomy similar to modern species was found in 79-million-year-old Canadian amber from the Cretaceous. An older sister species with more primitive features was found in Burmese amber that is 90 to 100 million years old. Two mosquito fossils have been found that show very little morphological change in modern mosquitoes against their counterpart from 46 million years ago. These fossils are also the oldest ever found to have blood preserved within their abdomens. Despite no fossils being found earlier than the Cretaceous, recent studies suggest that the earliest divergence of mosquitoes between the lineages leading to Anophelinae and Culicinae occurred 226 million years ago.
Stokesosaurus
The Morrison Formation is a sequence of shallow marine and alluvial sediments which, according to radiometric dating, ranges between 156.3 million years old (Ma) at its base, to 146.8 million years old at the top, which places it in the late Oxfordian, Kimmeridgian, and early Tithonian stages of the Late Jurassic period. This formation is interpreted as a semiarid environment with distinct wet and dry seasons. The Morrison Basin where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins were carried by streams and rivers and deposited in swampy lowlands, lakes, river channels and floodplains. This formation is similar in age to the Solnhofen Limestone Formation in Germany and the Tendaguru Formation in Tanzania. In 1877 this formation became the center of the Bone Wars, a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope.
Dromaeosauridae
Dromaeosaurid fossils have been found across the globe in North America, Europe, Africa, Asia, South America and Antarctica, with fossilized teeth giving credence to the possibility that they inhabited Australia as well. They first appeared in the mid-Jurassic Period (late Bathonian stage, about 167 million years ago) and survived until the end of the Cretaceous (Maastrichtian stage, 66 ma), existing until the Cretaceous–Paleogene extinction event. The presence of dromaeosaurids as early as the Middle Jurassic has been suggested by the discovery of isolated fossil teeth, though no dromaeosaurid body fossils have been found from this period.
Plateosaurus
Plateosaurus (probably meaning "broad lizard", often mistranslated as "flat lizard") is a genus of plateosaurid dinosaur that lived during the Late Triassic period, around 214 to 204 million years ago, in what is now Central and Northern Europe and Greenland, North America. "Plateosaurus" is a basal (early) sauropodomorph dinosaur, a so-called "prosauropod". As of 2011, two species are recognised: the type species "P. engelhardti" from the late Norian and Rhaetian, and the slightly earlier "P. gracilis" from the lower Norian. However, others have been assigned in the past, and there is no broad consensus on the species taxonomy of plateosaurid dinosaurs. Similarly, there are a plethora of synonyms (invalid duplicate names) at the genus level.
Bagaceratops
Bagaceratops, meaning "small-horned face" (Mongolian "Baga" = "small"; Greek "ceratops" = "horn face"), is a genus of ceratopsian dinosaur that lived in what is now Mongolia around 80 million years ago, during the Late Cretaceous. Although emerging late in the reign of the dinosaurs, "Bagaceratops" had a fairly primitive anatomy and kept the small body size that characterized early ceratopsians.
Docodonta
Docodonta is an order of extinct mammaliaforms that lived during the Mesozoic, from the Middle Jurassic to Early Cretaceous. They are distinguished from other early mammaliaforms by their relatively complex molar teeth, from which the order gets its name. Until recently, Docodonta were represented primarily by 
teeth and jaws found across former Laurasia, (modern-day North America, Europe, and Asia). However, recent discoveries in China include some exceptionally well preserved, almost complete body fossils.
Brachiosaurus
"Brachiosaurus" is known only from the Morrison Formation of western North America (following the reassignment of the African species). The Morrison Formation is interpreted as a semiarid environment with distinct wet and dry seasons, and flat floodplains. Several other sauropod genera were present in the Morrison Formation, with differing body proportions and feeding adaptations. Among these were "Apatosaurus", "Barosaurus", "Camarasaurus", "Diplodocus", "Haplocanthosaurus", and "Supersaurus". "Brachiosaurus" was one of the less abundant Morrison Formation sauropods. In a 2003 survey of over 200 fossil localities, John Foster reported 12 specimens of the genus, comparable to "Barosaurus" (13) and "Haplocanthosaurus" (12), but far fewer than "Apatosaurus" (112), "Camarasaurus" (179), and "Diplodocus" (98). "Brachiosaurus" fossils are found only in the lower-middle part of the expansive Morrison Formation (stratigraphic zones 2–4), dated to about 154–153 million years ago, unlike many other types of sauropod which have been found throughout the formation. If the large foot reported from Wyoming (the northernmost occurrence of a brachiosaurid in North America) did belong to "Brachiosaurus", the genus would have covered a wide range of latitudes. Brachiosaurids could process tough vegetation with their broad-crowned teeth, and might therefore have covered a wider range of vegetational zones than for example diplodocids. Camarasaurids, which were similar in tooth morphology to brachiosaurids, were also widespread and are known to have migrated seasonally, so this might have also been true for brachiosaurids.
Docodontidae
Docodontidae is an extinct family of omnivorous, ecologically diverse mammaliformes that lived during the Early (Toarcian) to Upper Jurassic. Their remains have been found in Europe, Asia and North America. The mesiolingual part of lower molars regularly have wear.
2011 in archosaur paleontology
The year 2011 in Archosaur paleontology was eventful. Archosaurs include the only living dinosaur group — birds — and the reptile crocodilians, plus all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosaur palaeontology is the scientific study of those animals, especially as they existed before the Holocene Epoch began about 11,700 years ago. The year 2011 in paleontology included various significant developments regarding archosaurs.
Dinosaur
Dinosaurs diverged from their archosaur ancestors during the middle to late Triassic period, roughly 20 million years after the Permian–Triassic extinction event wiped out an estimated 95% of all life on Earth. Radiometric dating of the rock formation that contained fossils from the early dinosaur genus "Eoraptor" at 231.4 million years old establishes its presence in the fossil record at this time. Paleontologists think that "Eoraptor" resembles the common ancestor of all dinosaurs; if this is true, its traits suggest that the first dinosaurs were small, bipedal predators. The discovery of primitive, dinosaur-like ornithodirans such as "Marasuchus" and "Lagerpeton" in Argentinian Middle Triassic strata supports this view; analysis of recovered fossils suggests that these animals were indeed small, bipedal predators. Dinosaurs may have appeared as early as 243 million years ago, as evidenced by remains of the genus "Nyasasaurus" from that period, though known fossils of these animals are too fragmentary to tell if they are dinosaurs or very close dinosaurian relatives. Recently, it has been determined that "Staurikosaurus" from the Santa Maria Formation dates to 233.23 Ma, making it older in geologic age than "Eoraptor".
Dryosaurus
The "Dryosaurus" holotype specimen YPM 1876 was discovered in Reed’s YPM Quarry 5, in the Upper Brushy Basin Member, of the Morrison Formation. In the Late Jurassic Morrison formation of Western North America, "Dryosaurus" remains have been recovered from stratigraphic zones 2-6. A spectacular digsite near Uravan, Colorado held hundreds of "D. altus" fossils which represented multiple stages of the animal's life cycle. This formation is a sequence of shallow marine and alluvial sediments which, according to radiometric dating, ranges between 156.3 million years old (Ma) at its base, to 146.8 million years old at the top, which places it in the late Oxfordian, Kimmeridgian, and early Tithonian stages of the Late Jurassic period. In 1877 this formation became the center of the Bone Wars, a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope. The Morrison Formation is interpreted as a semiarid environment with distinct wet and dry seasons. The Morrison Basin where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins were carried by streams and rivers and deposited in swampy lowlands, lakes, river channels and floodplains. This formation is similar in age to the Solnhofen Limestone Formation in Germany and the Tendaguru Formation in Tanzania.
Maniraptoriformes
Many nearly complete fossil maniraptoriforms are known from the late Jurassic. "Archaeopteryx" is known from Bavaria at 155-150 Ma. "Ornitholestes", the troodontid WDC DML 001, "Coelurus fragilis" and "Tanycolagreus topwilsoni" are all known from the Morrison Formation in Wyoming at about 150 Ma. The Daohugou biota, including "Anchiornis" and "Epidexipteryx", is the earliest record of maniraptoriformes, dating to about 160 Ma. One possible maniraptoriform, "Eshanosaurus", lived even earlier, during the Early Jurassic, though its identification is controversial.
Mesozoic
The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs. The Mesozoic was a time of significant tectonic, climate and evolutionary activity. The era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. Dinosaurs first appeared in the Mid-Triassic, and became the dominant terrestrial vertebrates in the Late Triassic or Early Jurassic, occupying this position for about 150 or 135 million years until their demise at the end of the Cretaceous. Birds first appeared in the Jurassic (However true Birds (toothless) appeared first in the Cretaceous), having evolved from a branch of theropod dinosaurs. The first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg (33 lb)—until the Cenozoic.
Plesiosauroidea
Plesiosauroidea appeared at the Early Jurassic Period (late Sinemurian stage) and thrived until the K-Pg extinction, at the end of the Cretaceous Period. The oldest confirmed plesiosauroid is "Plesiosaurus" itself, as all younger taxa were recently found to be pliosauroids. While they were Mesozoic diapsid reptiles that lived at the same time as dinosaurs, they did not belong to the latter. Gastroliths are frequently found associated with plesiosaurs.
List of creatures in Primeval
The skull was more robustly built than other Mosasaurs, as the mandibles articulated very tightly with the skull. It had a deep, barrel-shaped body, and with its fairly large eyes, poor binocular vision, and poorly developed olfactory bulbs, experts believe that "Mosasaurs" lived near the ocean surface, where it preyed on fish, turtles, ammonites as well as smaller "Mosasaurs". Because of its robust skull and tightly articulating jaws, mosasaurs was unable to swallow prey-items whole in the manner of earlier mosasaurs, such as "Tylosaurus". Instead, with the aid of its curved, knife-like teeth, mosasaurs was able to tear its prey into more manageable pieces that could be more easily swallowed.
Anchisauria
The Anchisauria were a clade of sauropodomorph dinosaurs that lived during the Late Triassic and Early Jurassic. The name Anchisauria was first used by Galton and Upchurch in the second edition of "The Dinosauria". Galton and Upchurch assigned two families of dinosaurs to the Anchisauria: the Anchisauridae and the Melanorosauridae. The more common prosauropods "Plateosaurus" and "Massospondylus" were placed in the sister clade Plateosauria.
Simoedosaurus
Simoedosaurus is an extinct reptile known from the Paleocene of North America, Europe and western Asia, and a member of the Choristodera, a group of aquatic reptiles that lived in the Northern Hemisphere from the Jurassic to the early Cenozoic.
List of informally named dinosaurs
"Thotobolosaurus" or "Kholumolumosaurus" is the name given to an as yet not formally described genus of dinosaur. It lived during the Late Triassic (Carnian to Norian stage). "Thotobolosaurus" lived in what is present-day Lesotho, and is believed to have been a prosauropod or early sauropod. The suggested "type species", "Thotobolosaurus mabeatae", was coined by Paul Ellenberger in 1970. Although the fossils have been referred to in scientific literature since the 1970s, this African dinosaur has never been formally described, and is considered a "nomen nudum". The name "Thotobolosaurus" comes from Sesotho South African, Thotobolo for "trash heap", referring to where the fossil remains were found, in 1955 by paleontologist Paul Ellenberger, in the immediate vicinity of a refuse pile a few meters from native huts in the Village of Maphutseng, western Lesotho. The specific name, "T. mabeatae", is named after an elderly woman and local resident of the western Lesotho village of Maphutseng whose name was 'Mabeata (from Sesotho, meaning "Mother of Beata"). Remains of the type fossil were found by the author and party in the immediate vicinity of 'Mabeata's refuse pile, located close by her hut. Mabeatae is a feminine proper name in the Latin genitive case.
Sauropsida
Sauropsids evolved from basal amniotes stock approximately 320 million years ago in the Paleozoic Era. In the Mesozoic Era (from about 250 million years ago to about 66 million years ago), sauropsids were the largest animals on land, in the water, and in the air. The Mesozoic is sometimes called the Age of Reptiles. Sixty-six million years ago, the large-bodied sauropsids died out in the global extinction event at the end of the Mesozoic era. With the exception of a few species of birds, the entire dinosaur lineage became extinct; in the following era, the Cenozoic, the remaining birds diversified so extensively that, today, nearly one out of every three species of land vertebrate is a bird species.
Brontosaurus
The Morrison Formation is a sequence of shallow marine and alluvial sediments which, according to radiometric dating, ranges between 156.3 million years old (Mya) at its base, and 146.8 Mya at the top, which places it in the late Oxfordian, Kimmeridgian, and early Tithonian stages of the Late Jurassic period. This formation is interpreted as a semiarid environment with distinct wet and dry seasons. The Morrison Basin, where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins were carried by streams and rivers and deposited in swampy lowlands, lakes, river channels, and floodplains. This formation is similar in age to the Lourinha Formation in Portugal and the Tendaguru Formation in Tanzania.
Dinosaurs Alive!
Dinosaurs Alive! is a 2007 IMAX documentary produced by Giant Screen Films about various dinosaurs that inhabited the Earth between 251 and 65 Ma. The documentary features animals from the Triassic period of New Mexico to the Cretaceous period of Mongolia.
Mosasaur
The first publicized discovery of a partial fossil mosasaur skull in 1764 by quarry workers in a subterranean gallery of a limestone quarry in Mount Saint Peter, near the Dutch city of Maastricht, preceded any major dinosaur fossil discoveries, but remained little known. However, a second find of a partial skull drew the Age of Enlightenment's attention to the existence of fossilized animals that were different from any known living creatures. When the specimen was discovered between 1770 and 1774, Johann Leonard Hoffmann, a surgeon and fossil collector, corresponded about it with the most influential scientists of his day, making the fossil famous. The original owner, though, was Godding, a canon of Maastricht cathedral.
Mojoceratops
Mojoceratops is a genus of ceratopsian dinosaur. It is a chasmosaurine ceratopsid which lived during the Late Cretaceous period, in what is now Western Canada. The genus is based on skulls first assigned to species of the contemporary ceratopsid "Chasmosaurus". First given a unique name in 2010, later research has suggested that "Mojoceratops" is a synonym of "Chasmosaurus" as originally thought.
Evolution of lemurs
The second major episode of diversification occurred during the Late Miocene, approximately 8 to 12 mya, and included the true lemurs ("Eulemur") and the mouse lemurs ("Microcebus"). This event coincided with the beginning of the Indian monsoons, the last major change in climate to affect Madagascar. The populations of both the true lemurs and mouse lemurs were thought to have diverged due to habitat fragmentation when humans arrived on the island roughly 2,000 years ago. Only recently has molecular research shown a more distant split in these genera. Most surprising were the mouse lemurs, a group which is now thought to contain cryptic species, meaning they are indistinguishable from each other based solely on appearance. In contrast, true lemurs are easier to distinguish and exhibit sexual dichromatism. Studies in karyology, molecular genetics, and biogeographic patterns have also assisted in understanding their phylogeny and diversification. Although the divergence estimates for these two genera are imprecise, they overlap with a change to a wetter climate in Madagascar, as new weather patterns generated monsoons and likely influenced the plant life.
Dolichorhynchops
In 1918, Charles H. Sternberg found a large mosasaur, "Tylosaurus", with the remains of a plesiosaur in its stomach. The mosasaur specimen is currently mounted in the United States National Museum (Smithsonian) and the plesiosaur remains are stored in the collections. Although these important specimens were briefly reported by , the information was lost to science until 2001. This specimen was rediscovered and described by . It is the basis for the story line in the 2007 National Geographic IMAX documentary "", and a book by the same name .
Massospondylus
Massospondylus ( ; from Greek, (massōn, "longer") and (spondylos, "vertebra")) is a genus of sauropodomorph dinosaur from the Early Jurassic Period (Hettangian to Pliensbachian ages, ca. 200–183 million years ago). It was described by Sir Richard Owen in 1854 from remains discovered in South Africa, and is thus one of the first dinosaurs to have been named. Fossils have since been found at other locations in South Africa, Lesotho, and Zimbabwe. Material from Arizona's Kayenta Formation, India, and Argentina has been assigned to this genus at various times, but the Arizonan and Argentinian material are now assigned to other genera.
Diplodocus
This genus of dinosaurs lived in what is now mid-western North America at the end of the Jurassic period. "Diplodocus" is one of the more common dinosaur fossils found in the middle to upper Morrison Formation, between about 154 and 152 million years ago, during the late Kimmeridgian age. The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs, such as "Apatosaurus", "Barosaurus", "Brachiosaurus", "Brontosaurus", and "Camarasaurus".
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201 million years ago; their dominance continued through the Jurassic and Cretaceous periods. Reverse genetic engineering and the fossil record both demonstrate that birds are modern feathered dinosaurs, having evolved from earlier theropods during the late Jurassic Period. As such, birds were the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event 66 million years ago. Dinosaurs can therefore be divided into "avian dinosaurs", or birds; and "non-avian dinosaurs", which are all dinosaurs other than birds. This article deals primarily with non-avian dinosaurs.
Paleontology in Montana
For thirty million years following the deposition of the Morrison Formation sediments in Montana were being eroded rather than deposited. Seawater was still present in Montana, now extending as an embayment down from the Arctic Circle. Rivers were still flowing into the local sea, but the local dinosaur fauna was very different. Carnivores living here included "Deinonychus" and "Microvenator". Herbivores included "Sauropelta" and "Tenontosaurus". Around this time flowering plants would make their first appearance in the state. During the middle part of the Cretaceous Montana was partially covered by the Western Interior Seaway. Significant volcanic eruptions occurred in Montana during the time of the Western Interior Seaway. This sea was home to cephalopods, clams, and plesiosaurs. The sediments deposited by this sea compose what is now called the Colorado Group. No dinosaur fossils are known to have been preserved in the Colorado group in Montana, but outside the state occasional discoveries have been made. Southwestern Montana was dry land, but none of those deposits have yielded dinosaur fossils yet. 85 million years ago the Western Interior Seaway withdrew slightly leaving western Montana as a coastal plain. Dinosaurs were present but rarely left fossilized remains. The sea was home to animals such as cephalopods, gastropods, mosasaurs, pelecypods, and plesiosaurs.
Tethysaurinae
Tethysaurines were primitive and comparatively small to medium-sized mosasaurs that lived during the earlier stages of mosasaur evolutionary history. "Tethysaurus" itself is approximately 3 metres long, whilst "Pannoniasaurus" might have reached lengths of 6 metres. They had a plesiopedal limb condition, meaning that they were not as well adapted to marine life as later mosasaurs and probably kept to shallow bodies of water. "Pannoniasaurus" is the only known mosasaur recovered from freshwater deposits.
Elasmosauridae
Elasmosauridae was a family of plesiosaurs. They had the longest necks of the plesiosaurs and survived from the Late Triassic to the end of the Cretaceous. Their diet mainly consisted of crustaceans and molluscs.
Cosesaurus
Cosesaurus is a genus of archosauromorph reptiles likely belonging to the family Tanystropheidae. It is known from fossil imprints of a single small skeleton, MGB V1, which was found in Muschelkalk outcrops near the municipalities of Mont-ral and Alcover in Spain. These outcrops are dated to the Ladinian age of the middle Triassic about 242 to 237 million years ago. The specimen is stored at the Museu Martorell (a.k.a. the Museu Geologia de Barcelona), which is now part of the Museu de Ciències Naturals de Barcelona. The poor preservation and likely juvenile nature of the specimen has led to the anatomy of "Cosesaurus" being misidentified by several different sources. For example, Paul Ellenberger claimed that it was an ancestor to birds in the 1970s, while Dave Peters claimed that it was a pterosaur ancestor in 2000. Both of these claims contrast with mainstream scientific theories on the origins of either group, and other paleontologists who study the specimen are unable to find the features which Ellenberger or Peters reported to be present. The Ellenberger and Peters hypotheses are thus considered fringe theories with questionable scientific soundness due to their low reproducibility. Mainstream hypotheses for the relations of "Cosesaurus" generally agree that it is a "protorosaur", specifically a tanystropheid closely related to long-necked reptiles such as "Macrocnemus", "Tanytrachelos", "Tanystropheus", or "Langobardisaurus".
Achelousaurus
Achelousaurus ( ) is a genus of centrosaurine ceratopsid dinosaur that lived during the Late Cretaceous Period of what is now North America, about 74.2 million years ago. The first fossils of "Achelousaurus" were collected in Montana in 1987, by a team led by Jack Horner, with more finds made in 1989. In 1994, Achelousaurus horneri was described and named by Scott D. Sampson; the generic name means "Achelous lizard", in reference to a Greek mythological figure, and the specific name refers to Horner. The genus is known from a few specimens consisting mainly of skull material from individuals, ranging from juveniles to adults.
Isanosaurus
Isanosaurus (meaning "Isan [north-eastern Thailand] lizard") was one of the first sauropod dinosaurs. It lived approximately 210 million years ago during the Upper Triassic (late Norian to Rhaetian stages) in Thailand. The only species is "Isanosaurus attavipachi". Though important for the understanding of sauropod origin and early evolution, "Isanosaurus" is poorly known. Exact relationships to other early sauropods remain unresolved.
Goronyosaurus
Goronyosaurus is an extinct genus of marine lizard belonging to the mosasaur family. Fossils of "Goronyosaurus" are exclusively known from the Dukamaje Formation of Niger and Nigeria and are Maastrichtian in age. Its fossils were first described in the 1930s as Mosasaurus nigeriensis, but subsequent remains revealed a highly unique set of adaptations that prompted the species to be reclassified as the only species of the new genus "Goronyosaurus" in 1972. These unique adaptations have made "Goronyosaurus" notoriously difficult to classify within the Mosasauridae and it is often left out of phylogenetic analyses.
Mussaurus
Mussaurus (meaning "mouse lizard") is a genus of herbivorous sauropodomorph dinosaur that lived in southern Argentina during the Late Triassic, about 215 million years ago. It receives its name from the small size of the skeletons of juvenile and infant individuals, which were once the only known specimens of the genus. However, since "Mussaurus" is now known from adult specimens, the name is something of a misnomer; adults possibly reached 3 m (10 ft) in length, and weighed . "Mussaurus" possesses anatomical features suggesting a close, possibly transitional evolutionary relationship with true sauropods.
Mosasaurinae
The lineage first appears in the Turonian and thrived until the mass extinction event at the end of the Maastrichtian. They ranged in size from some of the smallest known mosasaurs ("Carinodens", 3–3.5 meters), to medium-sized taxa ("Clidastes", 6+ meters), to the largest of the mosasaurs ("Mosasaurus hoffmannii") potentially reaching about 15 m in length. Many genera of mosasaurines were either piscivorous or generalists, preying on fish and other marine reptiles, but one lineage, the Globidensini, evolved specialized crushing teeth, adapting to a diet of ammonites and/or marine turtles.
Cochleosaurus
Cochleosaurus ('spoon lizard') is a name of a tetrapod belonging to Temnospondyli, which lived during the late Carboniferous period (Moscovian, about 310 millions years ago). The great abundance of its remains (about 50 specimens) have been found in the Kladno Formation of the Czech Republic, near Nýřany in Central Europe and in the Morien Group of Nova Scotia in North America. It was a creature of medium size, measuring 120-160 centimeters. It is believed that "Cochleosaurus" was a semiaquatic ambush predator, hunting like modern crocodiles. Czech paleontologist Antonin Fritsch named the genus in 1885 in reference to the spoon-shaped processes on the supra-occipital bones at the back of the skull (from Latin "cochlear" "spoon" and Greek "sauros" "lizard").
Mierasaurus
Asides from "Mierasaurus" and "Moabosaurus", all other turiasaurs are Jurassic in age, and turiasaurs had previously been considered to have gone extinct at the Jurassic-Cretaceous boundary. However, turiasaurs are not known from the Jurassic-aged (more specifically, dating to the Tithonian epoch) deposits of the Morrison Formation, or from any other equivalent deposits in western (Laramidian) North America. This means that they may have reached North America at some point after the Tithonian, although the possibility that they were present but have not been found cannot be excluded. It is also possible that they were present in eastern (Appalachian) North America in the Late Jurassic, and spread to Laramidian North America subsequently. However, the presence of "Mierasaurus" in Valanginian deposits correlates with a substantial drop in sea level that occurred during the epoch, which may have formed a land bridge and allowed turiasaurs - and potentially other groups, such as haramiyidan mammals - to spread from Europe to North America.
Mosasaurus
Mosasaurus (; "lizard of the Meuse River") is a genus of mosasaurs, extinct carnivorous aquatic lizards. It existed during the Maastrichtian age of the late Cretaceous period, between about 70 and 66 million years ago, in western Europe and North America. The name means "Meuse lizard", as the first specimen was found near the Meuse River (Latin "Mosa" + Greek "sauros" lizard).
Elasmosaurus
Elasmosaurus (;) is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, about 80.5million years ago. The first specimen was discovered in 1867 near Fort Wallace, Kansas, and was sent to the American paleontologist Edward Drinker Cope, who named it E.platyurus in 1868. The generic name means "thin-plate reptile", and the specific name means "flat-tailed". Cope originally reconstructed the skeleton of "Elasmosaurus" with the skull at the end of the tail, an error which was made light of by the paleontologist Othniel Charles Marsh, and became part of their "Bone Wars" rivalry. Only one incomplete "Elasmosaurus" skeleton is definitely known, consisting of a fragmentary skull, the spine, and the pectoral and pelvic girdles, and a single species is recognized today; other species are now considered invalid or have been moved to other genera.
Timeline of mosasaur research
This timeline of mosasaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of mosasaurs, a group of giant marine lizards that lived during the Late Cretaceous Epoch. Although mosasaurs went extinct millions of years before humans evolved, humans have coexisted with mosasaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about warfare between serpentine water monsters and aerial thunderbirds told by the Native Americans of the modern western United States may have been influenced by observations of mosasaur fossils and their co-occurrence with creatures like "Pteranodon" and "Hesperornis".
Moanasaurus
Moanasaurus (From Māori "moana" "sea" and Greek "sauros" "lizard"; meaning "Sea Lizard") was a genus of mosasaur from the Late Cretaceous period. Its fossil remains have been discovered in the North Island of New Zealand. "Moanasaurus" was a very large mosasaurine known originally from a disarticulated skull, vertebrae, ribs and flipper bones. It reached 12 m in length and the skull is 78 cm, which shows that "Moanasaurus" was one of the largest in the family of Mosasaurinae.
Plesiosauria
While the Loch Ness monster is often reported as looking like a plesiosaur, it is also often described as looking completely different. A number of reasons have been presented for why a plesiosaurian identity is unlikely. These include the assumption that the water in the loch is too cold for a, for the sake of this argument, presumed cold-blooded reptile to be able to survive easily, the assumption that air-breathing animals would be easy to see whenever they appear at the surface to breathe, the fact that the loch is too small and contains insufficient food to be able to support a breeding colony of large animals, and finally the fact that the lake was only formed 10,000 years ago at the end of the last ice age, while the latest fossil appearance of plesiosaurs dates to over 66 million years ago. Frequent explanations for the sightings include waves, floating inanimate objects, tricks of the light, swimming known animals, and practical jokes. Nevertheless, in the popular imagination, plesiosaurs have come to be identified with the Monster of Loch Ness. This has had the advantage of making the group better known to the general public, but the disadvantage that people have trouble taking the subject seriously, forcing paleontologists to explain time and time again that plesiosaurs really did exist and are not creatures of myth or fantasy.
Timeline of plesiosaur research
This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles that flourished during the Mesozoic Era. The first scientifically documented plesiosaur fossils were discovered during the early by Mary Anning. Plesiosaurs were actually discovered and described before dinosaurs. They were also among the first animals to be featured in artistic reconstructions of the ancient world, and therefore among the earliest prehistoric creatures to attract the attention of the lay public. Plesiosaurs were originally thought to be a kind of primitive transitional form between marine life and terrestrial reptiles. However, now plesiosaurs are recognized as highly derived marine reptiles descended from terrestrial ancestors.
Titanosaur
The titanosaurs were the last great group of sauropods, which existed from about 136 to 66 million years ago, before the Cretaceous–Paleogene extinction event, and were the dominant herbivores of their time. The fossil evidence suggests they replaced the other sauropods, like the diplodocids and the brachiosaurids, which died out between the late Jurassic and the mid-Cretaceous Periods.
Timeline of mosasaur research
By this time the first mosasaur fossils from the United States were discovered by the Lewis and Clark expedition, and the first remains in the country to be scientifically described were reported slightly later from New Jersey. This was followed by an avalanche of discoveries by the feuding Bone War paleontologists Edward Drinker Cope and Othniel Charles Marsh in the Smoky Hill Chalk of Kansas. By the end of the century a specimen of "Tylosaurus" would be found that preserved its scaley skin. Later Samuel Wendell Williston mistook fossilized tracheal rings for the remains of a fringe of skin running down the animal’s back, which subsequently became a common inaccuracy in artistic restorations.
Quaesitosaurus
Quaesitosaurus (meaning "extraordinary lizard") is a genus of titanosaurian sauropod found by Kurzanov and Bannikov in 1983. The type species is "Quaesitosaurus orientalis". It lived from 85 to 70 million years ago during the Late Cretaceous (Santonian to Campanian ages). Its fossils, consisting solely of a partial skull, were found in the Barun Goyot Formation near Shar Tsav, Mongolia. Long, low and horse-like with frontally located peg-teeth, it is similar enough to the skulls of "Diplodocus" and its kin to have prompted informed speculation that the missing body was formed like those of diplodocids.
Melanorosauridae
The Melanorosauridae were a family of sauropodomorph dinosaurs which lived during the Late Triassic and Early Jurassic. The name Melanorosauridae was first coined by Friedrich von Huene in 1929. Huene assigned several families of dinosaurs to the infraorder "Prosauropoda": the Anchisauridae, the Plateosauridae, the Thecodontosauridae, and the Melanorosauridae. Since then, these families have undergone numerous revisions. Galton and Upchurch (2004) considered "Camelotia", "Lessemsaurus", and "Melanorosaurus" members of the family Melanorosauridae. A more recent study by Yates (2007) indicates that the melanorosaurids were instead early sauropods.
Mosasaurini
The Mosasaurini are a tribe of mosasaurine mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the tribe, known as "mosasaurins", have been recovered from North America, Europe, Africa and Oceania with questionable occurrences in Asia. The tribe contains the closely related genera "Mosasaurus", "Eremiasaurus", "Plotosaurus" and "Moanasaurus". It has historically been more inclusive, on occasion including genera such as "Plesiotylosaurus", "Liodon" and "Clidastes", all of which are now seen as more basal mosasaurines.
Tylosaurinae
The Tylosaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "tylosaurines" and have been recovered from every continent except for South America. The subfamily includes the genera "Tylosaurus", "Taniwhasaurus", "Hainosaurus" and "Kaikaifilu".
Mosquito
Mosquitoes diverged from other insects about 226 million years ago. Fossils of primitive mosquitoes have been found that are over 90 million years old; fossils similar to modern mosquitoes, 79 million years old; fossils identical to modern mosquitoes, 46 million years old. The life cycle consists of the egg, larva, pupa, and adult. Eggs are laid on the water surface; they hatch into motile larvae which feed on aquatic algae and organic material; pupae are breathing non-flying primitive adults.
Mesozoic
The Middle Jurassic spans from 175 to 163 million years ago. During this epoch, dinosaurs flourished as huge herds of sauropods, such as "Brachiosaurus" and "Diplodocus", filled the fern prairies, chased by many new predators such as "Allosaurus". Conifer forests made up a large portion of the forests. In the oceans, plesiosaurs were quite common, and ichthyosaurs flourished. This epoch was the peak of the reptiles.
Phanerozoic
The Early Jurassic Epoch spans from 201 million to 174 million years ago. The climate was much more humid than the Triassic, and as a result, the world was very tropical. In the oceans, plesiosaurs, ichthyosaurs and ammonites dominated the seas. On land, dinosaurs and other reptiles dominated the land, with species such as "Dilophosaurus" at the apex. The first true crocodiles evolved, pushing the large amphibians to near extinction. The reptiles rose to rule the world. Meanwhile, the first true mammals evolved, but never exceeded the height of a shrew.
High Atlas
This massif became an internationally famous paleontological site after the discovery of the bones of a dinosaur called 'Atlasaurus', which populated Morocco 180 million years ago. This dinosaur is also named Tazoudasaurus, after the name of the village of Tazouda, where it was discovered. The creature, about long, is postulated to be an ancestor of the Sauropoda found in America. Until 140 million years ago, the African and American continents were connected.
Barosaurus
"Barosaurus" remains are limited to the Morrison Formation, which is widespread in the western United States between the Great Plains and Rocky Mountains. Radiometric dating agrees with biostratigraphic and paleomagnetic studies, indicating that the Morrison was deposited during the Kimmeridgian and early Tithonian stages of the Late Jurassic Period, or approximately 155 to 148 million years ago. "Barosaurus" fossils are found in late Kimmeridgian to early Tithonian sediments, around 150 million years old.
The Morrison Formation was deposited in floodplains along the edge of the ancient Sundance Sea, an arm of the Arctic Ocean which extended southward to cover the middle of North America as far south as the modern state of Colorado. Due to tectonic uplift to the west, the sea was receding to the north, and had retreated into what is now Canada by the time "Barosaurus" evolved. The sediments of the Morrison were washed down out of the western highlands, which had been uplifted during the earlier Nevadan orogeny and were now eroding. Very high atmospheric concentrations of carbon dioxide in the Late Jurassic led to high temperatures around the globe, due to the greenhouse effect. One study, estimating CO concentrations of 1120 parts per million, predicted average winter temperatures in western North America of and summer temperatures averaging . A more recent study suggested even higher CO concentrations of up to 3180 parts per million. Warm temperatures that led to significant evaporation year-round, along with possible rain shadow effect from the mountains to the west, led to a semi-arid climate with only seasonal rainfall. This formation is similar in age to the Solnhofen Limestone Formation in Germany and the Tendaguru Formation in Tanzania. In 1877 this formation became the center of the Bone Wars, a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope.
Massospondylidae
Massospondylidae is a family of early massopod dinosaurs that existed in Asia, Africa, South America and Antarctica during the Late Triassic to the Early Jurassic periods. Several dinosaurs have been classified as massospondylids over the years. The largest cladistic analysis of early sauropodomorphs, which was presented by Apaldetti and colleagues in November 2011, found "Adeopapposaurus", "Coloradisaurus", "Glacialisaurus", "Massospondylus", "Leyesaurus" and "Lufengosaurus" to be massospondylids. This result supports many previous analyses that tested fewer taxa. However, this analysis found the two recently described North American massopods, "Sarahsaurus" and "Seitaad", and the South African "Ignavusaurus" to nest outside Massospondylidae, as opposed to some provisional proposals. Earlier in 2011, "Pradhania", a sauropodomorph from India, was tested for the first time in a large cladistic analysis and was found to be a relatively basal massospondylid. "Mussaurus" and "Xixiposaurus" may also be included within Massospondylidae.
2009 in archosaur paleontology
The year 2009 in Archosaur paleontology was eventful. Archosaurs include the only living dinosaur group — birds — and the reptile crocodilians, plus all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosaur paleontology is the scientific study of those animals, especially as they existed before the Holocene Epoch began about 11,700 years ago. The year 2009 in paleontology included various significant developments regarding archosaurs.
Paleobiota of the Niobrara Formation
Mosasaurs are the most common marine reptiles in the Niobrara Chalk and the most successful ones in the sea at the time. Four different genre representing the four different subfamilies of Mosasauridae: the Tylosaurinae, Plioplatecarpinae, Mosasaurinae, and Halisaurinae, were present in Niobrara. They were the dominant carnivorous marine reptiles and ate cephalopods, fish, turtles, pterosaurs, birds, and even plesiosaurs. There is evidence of them consuming other smaller mosasaurs. Despite this, mosasaurs often fell prey to some of the large sharks at the time, such as "Cretoxyrhina".
Paleontology in the United States
The Mesozoic era followed and the dinosaurs began their rise to dominance, spreading into the country before Pangaea split up. During the latter Jurassic Morrison Formation dinosaurs lived in the western states. During the Cretaceous, the Gulf of Mexico expanded until it split North America in half. Plesiosaurs and mosasaurs swam in its waters. Later it began to withdraw and the western states were home to the Hell Creek dinosaurs. Another mass extinction ended the reign of the dinosaurs.
Mosasaur
Many of the so-called 'dinosaur' remains found on New Zealand are actually mosasaurs and plesiosaurs, both being Mesozoic predatory marine reptiles.
Coosina
Coosina is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period. It is one of oldest fossils.
Mixosauria
The Mixosauria were an early group of ichthyosaurs, living between 250 and 235 million years ago, during the Triassic period. Fossils of mixosaurs have been found all over the world: China, Timor, Indonesia, Italy, Germany, Spitsbergen, Switzerland, Svalbard, Canada, Alaska, and Nevada.
Saltoposuchus
Fossils found in Germany indicate that "Saltoposuchus" existed in Europe, or more appropriately, Laurasia. The Mesozoic Era has been regarded as "The Age of Reptiles" so "Saltoposuchus" lived among many different species including the earliest species of pterosaurs and other bipedal reptilians. Archosaurs, the ancestor to Crocodylomorpha, made its first appearance in the middle of the Triassic era. This is also the period in which the earliest mammals started appearing. Therapsids dominated the Early - Middle Triassic Period, but as time went on, therapsids started becoming extinct and archosaurs became the dominant group of reptiles. After the Permian–Triassic extinction event wiped out 90% of species in the world, conifer forests started to recover, species started occupying and thriving in newly found ecological niches, Pangaea started splitting into Laurasia and Gondwana, and the air was very arid with hot summers and cold winters. After marine life had been wiped out by the mass extinction event, the Triassic waters were populated with very few families of fish. The Triassic Period showed the first development of modern stony corals and a time of modest reef building activity in the shallower waters of the Tethys near the coasts of Pangaea. During the Mesozoic Era, early mammals, reptilian species, and other insects populated the land. Insects that had survived the mass extinction and were existing during this time include spiders, scorpions, millipedes, centipedes, and a newer group of beetles.
Mosasaurinae
The Mosasaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "mosasaurines" and have been recovered from every continent except for South America.
Moreae
Few fossils can be definitively assigned to the Moreae. Fruits from the upper Eocene, Miocene and Tertiary have been assigned to "Broussonetia", and fruit matching modern "Morus" have been found in the early Eocene. Based on rates of molecular evolution in chloroplast and nuclear genes, the Moreae s.s. is estimated to be about 59–79 million years old. Nyree Zerega and colleagues proposed a Laurasian origin for the Moreae s.s., with three separate colonisations of South America (by "Sorocea", "Bagassa" and "Trophis") and a later colonisation of Africa by "Milicia".
2012 in archosaur paleontology
The year 2012 in Archosaur paleontology was eventful. Archosaurs include the only living dinosaur group — birds — and the reptile crocodilians, plus all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosaur palaeontology is the scientific study of those animals, especially as they existed before the Holocene Epoch began about 11,700 years ago. The year 2012 in paleontology included various significant developments regarding archosaurs.
Secondarily aquatic tetrapods
Living at the same time as, but not closely related to, dinosaurs, the mosasaurs resembled crocodiles but were more strongly adapted to marine life. They became extinct 66 million years ago, at the same time as the dinosaurs.
Plotosaurus
Plotosaurus ("swimmer lizard") is an extinct genus of mosasaur from the Upper Cretaceous (Maastrichtian) of Fresno County, California. Originally named "Kolposaurus" (meaning "bay lizard") by Berkeley paleontologist Charles Lewis Camp in 1942, it was changed to "Plotosaurus" in 1951 when Camp discovered the name had already been assigned to a type of nothosaur.
Niobrarasaurus
Niobrarasaurus (meaning "Niobrara lizard") is an extinct genus of nodosaurid ankylosaur which lived during the Cretaceous 87 to 82 million years ago. Its fossils were found in the Smoky Hill Chalk Member of the Niobrara Formation, in western Kansas, which would have been near the middle of Western Interior Sea during the Late Cretaceous. It was a nodosaurid, an ankylosaur without a clubbed tail. It was closely related to "Nodosaurus".
Mosasaur
When the French revolutionary forces occupied Maastricht in 1794, the carefully hidden fossil was uncovered, after a reward, it is said, of 600 bottles of wine, and transported to Paris. After it had been earlier interpreted as a fish, a crocodile, and a sperm whale, the first to understand its lizard affinities was the Dutch scientist Adriaan Gilles Camper in 1799. In 1808, Georges Cuvier confirmed this conclusion, although "le Grand Animal fossile de Maëstricht" was not actually named "Mosasaurus" ('Meuse reptile') until 1822 and not given its full species name, "Mosasaurus hoffmannii," until 1829. Several sets of mosasaur remains, that had been discovered earlier at Maastricht but were not identified as mosasaurs until the 19th century, have been on display in the Teylers Museum, Haarlem, procured from 1790.
Evolution of dinosaurs
These are followed by the basal Tetanurae, of whom fossils have been found from the mid Jurassic to past the end of the early Cretaceous 180 Ma to 94 Ma. They have a relatively short maxillary tooth row. They did not all branch off the evolutionary line leading to coelurosaurs at the same time. Basal tetanurans include Megalosauridae, spinosaurids, a diverse clade of allosaurs, and several genera of less certain affinities, including "Compsognathus". With the exception of "Compsognathus" they are large-bodied. Allosaurs form a distinct long-lived clade that share some cranial characters. They include the well known "Allosaurus" and "Sinraptor" among others.
Reptile
The sister group to Archosauromorpha is Lepidosauromorpha, containing lizards and tuataras, as well as their fossil relatives. Lepidosauromorpha contained at least one major group of the Mesozoic sea reptiles: the mosasaurs, which lived during the Cretaceous period. The phylogenetic placement of other main groups of fossil sea reptiles – the ichthyopterygians (including ichthyosaurs) and the sauropterygians, which evolved in the early Triassic – is more controversial. Different authors linked these groups either to lepidosauromorphs or to archosauromorphs, and ichthyopterygians were also argued to be diapsids that did not belong to the least inclusive clade containing lepidosauromorphs and archosauromorphs.
Timeline of mosasaur research
The 20th century soon saw the discovery in Alabama of a strange mosasaur called "Globidens", with rounded teeth suited to crushing shells. Mosasaur remains were also discovered in Africa and California. In 1967 Dale Russell published a scientific monograph dedicated to mosasaurs. Embryonic remains in the 1990s confirmed that mosasaurs gave live birth like in ichthyosaurs. The 1990s also saw a revival and escalation of a debate regarding whether or not some supposed mosasaur toothmarks in ammonoid shells were actually made by limpets. By the end of the century, the evolutionary relationship between mosasaurs and snakes as well as the possible involvement of mosasaurs in the extinction of the aforementioned ichthyosaurs became hot button controversies.
Plesiosauria
Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution.
Coloradisaurus
Coloradisaurus (meaning "Colorados [from Los Colorados Formation] lizard") is a genus of massospondylid sauropodomorph dinosaur. It lived during the Late Triassic period (Norian to Rhaetian stages) in what is now La Rioja Province, Argentina. It is known from the holotype PVL 5904, nearly complete skull. It was discovered and collected from the upper section of the Los Colorados Formation. Originally named "Coloradia" by Jose F. Bonaparte in 1978, this name had already been assigned to a moth, and so the animal was renamed. The genus was first named by David Lambert in 1983 and the type species is "Coloradisaurus brevis". It may in fact be an adult specimen of "Mussaurus". Cladistic analyses by Yates (2007), Yates "et al." (2010, 2011) and Novas "et al." (2011) found that "Coloradisaurus" is basal to the "Glacialisaurus"-"Lufengosaurus" clade within Massospondylidae.
Mosasaur
Despite the many mosasaur remains collected worldwide, knowledge of the nature of their skin coverings remains in its early stages. Few mosasaurid specimens collected from around the world retain fossilized scale imprints. This lack may be due to the delicate nature of the scales, which nearly eliminates the possibility of preservation, in addition to the preservation sediment types and the marine conditions under which the preservation occurred. Until the discovery of several mosasaur specimens with remarkably well-preserved scale imprints from late Maastrichtian deposits of the Muwaqqar Chalk Marl Formation of Harrana in Jordan, knowledge of the nature of mosasaur integument was mainly based on very few accounts describing early mosasaur fossils dating back to the upper Santonian–lower Campanian, such as the famous "Tylosaurus" specimen (KUVP-1075) from Gove County, Kansas. Material from Jordan has shown that the bodies of mosasaurs, as well as the membranes between their fingers and toes, were covered with small, overlapping, diamond-shaped scales resembling those of snakes. Much like those of modern reptiles, mosasaur scales varied across the body in type and size. In Harrana specimens, two types of scales were observed on a single specimen: keeled scales covering the upper regions of the body and smooth scales covering the lower. As ambush predators, lurking and quickly capturing prey using stealth tactics, they may have benefited from the nonreflective, keeled scales.
Niobrara Formation
During the time of the deposition of the Niobrara Chalk, much life inhabited the seas of the Western Interior Seaway. By this time in the Late Cretaceous many new lifeforms appeared such as mosasaurs, which were to be some of the last of the aquatic lifeforms to evolve before the end of the Mesozoic. Life of the Niobrara Chalk is comparable to that of the Dakota Formation, although the Dakota Formation, which was deposited during the Cenomanian, predates the chalk by about 10 million years.
Plioplatecarpus
"Plioplatecarpus" was first found in Europe by paleontologist Louis Dollo ("P. marshi"), in 1882. It was relatively incomplete, but more fossils would soon turn up. In North America, Edward Drinker Cope found another mosasaur in 1869, but had identified it as "Mosasaurus". It would later be reclassified as "Plioplatecarpus", as would Cope's "Liodon", in 1870. "Liodon" would be reclassified as "Platecarpus", and later as "Prognathodon". However, some have placed it in the genus "Plioplatecarpus".
Gongbusaurus
Gongbusaurus is a genus of ornithischian, perhaps ornithopod, dinosaur that lived between about 160 and 157 million years ago, in the Late Jurassic period. A small herbivore, it is very poorly known. Two species have been assigned to it, but as the original name is based on teeth, there is no concrete evidence to connect the two species. Its fossils have been found in China.
Marshosaurus
The Morrison Formation is a sequence of shallow marine and alluvial sediments which, according to radiometric dating, ranges between 156.3 million years old (Ma) at its base, to 146.8 million years old at the top, which places it in the late Oxfordian, Kimmeridgian, and early Tithonian stages of the Late Jurassic period. This formation is interpreted as a semiarid environment with distinct wet and dry seasons. The Morrison Basin where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins were carried by streams and rivers and deposited in swampy lowlands, lakes, river channels and floodplains. This formation is similar in age to the Solnhofen Limestone Formation in Germany and the Tendaguru Formation in Tanzania. In 1877 this formation became the center of the Bone Wars, a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope.
Tylosaurinae
Tylosaurines first appeared in the Coniacian and gave rise to some of the largest mosasaurs within the genera "Tylosaurus" and "Hainosaurus" which came to dominate as apex predators in marine ecosystems throughout the Santonian and Campanian, but appear to have been largely replaced by large mosasaurines, such as "Mosasaurus", by the end of the Maastrichtian. Nevertheless, the subfamily survived to the end of the Cretaceous, covering a period lasting approximately twenty million years.
Ceratosaurus
All North American "Ceratosaurus" finds come from the Morrison Formation, a sequence of shallow marine and alluvial sedimentary rocks in the western United States, and the most fertile source for dinosaur bones of the continent. According to radiometric dating, the age of the formation ranges between 156.3 million years old (Mya) at its base, and 146.8 million years old at the top, which places it in the late Oxfordian, Kimmeridgian, and early Tithonian stages of the Late Jurassic period. "Ceratosaurus" is known from Kimmeridgian and Tithonian strata of the formation. The Morrison Formation is interpreted as a semiarid environment with distinct wet and dry seasons. The Morrison Basin stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins were carried by streams and rivers and deposited in swampy lowlands, lakes, river channels, and floodplains. This formation is similar in age to the Lourinhã Formation in Portugal and the Tendaguru Formation in Tanzania.
The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs. Other dinosaurs known from the Morrison include the theropods "Koparion", "Stokesosaurus", "Ornitholestes", "Allosaurus", and "Torvosaurus"; the sauropods "Apatosaurus", "Brachiosaurus", "Camarasaurus", and "Diplodocus"; and the ornithischians "Camptosaurus", "Dryosaurus", "Othnielia", "Gargoyleosaurus", and "Stegosaurus". "Allosaurus", which accounted for 70 to 75% of all theropod specimens, was at the top trophic level of the Morrison food web. Other vertebrates that shared this paleoenvironment included ray-finned fishes, frogs, salamanders, turtles like "Dorsetochelys", sphenodonts, lizards, terrestrial and aquatic crocodylomorphans such as "Hoplosuchus", and several species of pterosaurs such as "Harpactognathus" and "Mesadactylus". Shells of bivalves and aquatic snails are also common. The flora of the period has been revealed by fossils of green algae, fungi, mosses, horsetails, cycads, ginkgoes, and several families of conifers. Vegetation varied from river-lining forests of tree ferns and ferns (gallery forests) to fern savannas with occasional trees such as the "Araucaria"-like conifer "Brachyphyllum".
2017 in archosaur paleontology
The year 2017 in archosaur paleontology was eventful. Archosaurs include the only living dinosaur group — birds — and the reptile crocodilians, plus all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosaur palaeontology is the scientific study of those animals, especially as they existed before the Holocene Epoch began about 11,700 years ago. The year 2017 in paleontology included various significant developments regarding archosaurs.
List of Vertebrate fauna of the Maastrichtian stage
This is an incomplete list that briefly describes vertebrates that were extant during the Maastrichtian, a stage of the Late Cretaceous Period which extended from 72.1 to 66 million years before present. This was the last time period in which non-avian dinosaurs, pterosaurs, plesiosaurs, and mosasaurs existed.
Mosasaurus
On Saturday, April 18, 2015, a fourteen-year-old amateur paleontologist, Lars Barten, from Rijkevoort village in Noord-Brabant province in the Netherlands, together with his father Jos Barten, discovered a "Mosasaurus hoffmani" fossil near ENCI-Maastricht. The fossil has been named Lars, after its finder and now resides in the Natuurhistorisch Museum Maastricht (Maastricht Natural History Museum).