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Bonitasaura is a genus of titanosaurian dinosaur hailing from uppermost layers of the Late Cretaceous (Santonian) Bajo de la Carpa Formation, Neuquén Group of the eastern Neuquén Basin, located in Río Negro Province, Northwestern Patagonia, Argentina. The remains, consisting of a partial sub-adult skeleton jumbled in a small area of fluvial sandstone, including a lower jaw with teeth, a partial vertebrae series, and limb bones, were described by Sebastian Apesteguía in 2004.
Malawisaurus is an extinct genus of titanosaurian sauropod dinosaur. It is known from the Dinosaur Beds of northern Malawi, which probably date to the Aptian stage of the Early Cretaceous. The type species is M. dixeyi and the specific name honours Frederick Augustus Dixey.
Protungulatum is an extinct genus of eutherian mammals within extinct family Protungulatidae, and is possibly one of the earliest known placental mammals in the fossil record, that lived in North America from the Late Cretaceous to early Paleocene.
The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian sub-period of the late Carboniferous period. By the mid-Triassic, there were many synapsid species that looked like mammals. The lineage leading to today's mammals split up in the Jurassic; synapsids from this period include Dryolestes, more closely related to extant placentals and marsupials than to monotremes, as well as Ambondro, more closely related to monotremes. Later on, the eutherian and metatherian lineages separated; the metatherians are the animals more closely related to the marsupials, while the eutherians are those more closely related to the placentals. Since Juramaia, the earliest known eutherian, lived 160 million years ago in the Jurassic, this divergence must have occurred in the same period.
Tyler R. Lyson is an American paleontologist. He is the discoverer of the dinosaur fossil Dakota, a fossilized mummified hadrosaur. He has done significant research on the evolution of turtles and on the rise of mammals after the extinction of the dinosaurs.
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Terminonaris is a genus of extinct pholidosaurid crocodyliforms that lived during the Late Cretaceous epoch. The name means: “enlarged snout or nose” at the front of the skull. Terminonaris is an early crocodile, within a subgroup called Mesoeucrocodylia. Its remains have only been found in North America and Europe. Originally known under the generic name Teleorhinus, it was once believed to be a teleosaurid. Both prehistoric crocodiles such as Terminonaris, as well as modern crocodiles, belong to the same group called crocodyliformes, although modern crocodiles have specific features that indicate they are distant relatives of this species and members of the subgroup Eusuchia.
William Alvin Clemens Jr. was a paleontologist at the University of California at Berkeley. He was faculty of the Department of Paleontology from 1967, then the Department of Integrative Biology from 1994 to his retirement and curator of the UC Museum of Paleontology. Clemens was also director of the museum (1987–1989) and chair of the Department of Paleontology (1987–1989). He was awarded a Guggenheim Fellowship (1974–75), a U.S. Senior Scientist Award by the Alexander von Humboldt Foundation, the Romer-Simpson Medal (2006), and was made a Fellow of the California Academy of Sciences.
The Dinosaur Beds is a geological formation in Malawi whose strata date back to the Early Cretaceous. The age of the deposit is poorly constrained, but is likely to date from the Barremian to Aptian. Dinosaurs, turtles and crocodylomorphs remains are among the fossils that have been recovered from the formation. It is correlated with the Galula Formation in Tanzania. It consists of two members, a lower unfossiliferous member consisting of deep red stained sandstones, and an upper fossiliferous member consisting of white sands and grey to red mudstones and siltstones. The upper member is 210 m thick in the vicinity of the CD-9 locality.
Scott Donald Sampson is a Canadian-American paleontologist and science communicator. Sampson is currently the Executive Director of California Academy of Sciences in San Francisco, California. He was previously Vice President of Research & Collections and Chief Curator at the Denver Museum of Nature & Science. Sampson is notable for his work on the carnivorous theropod dinosaurs Majungasaurus and Masiakasaurus and his extensive research into the Late Cretaceous Period, particularly in Madagascar. He is also known as the presenter of the PBS Kids show Dinosaur Train.
Several mammals are known from the Mesozoic of Madagascar. The Bathonian Ambondro, known from a piece of jaw with three teeth, is the earliest known mammal with molars showing the modern, tribosphenic pattern that is characteristic of marsupial and placental mammals. Interpretations of its affinities have differed; one proposal places it in a group known as Australosphenida with other Mesozoic tribosphenic mammals from the southern continents (Gondwana) as well as the monotremes, while others favor closer affinities with northern (Laurasian) tribosphenic mammals or specifically with placentals. At least five species are known from the Maastrichtian, including a yet undescribed species known from a nearly complete skeleton that may represent a completely new group of mammals. The gondwanathere Lavanify, known from two teeth, is most closely related to other gondwanatheres found in India and Argentina. Two other teeth may represent another gondwanathere or a different kind of mammal. One molar fragment is one of the few known remains of a multituberculate mammal from Gondwana and another has been interpreted as either a marsupial or a placental.
Paleontology in Texas refers to paleontological research occurring within or conducted by people from the U.S. state of Texas. Author Marian Murray has said that "Texas is as big for fossils as it is for everything else." Some of the most important fossil finds in United States history have come from Texas. Fossils can be found throughout most of the state. The fossil record of Texas spans almost the entire geologic column from Precambrian to Pleistocene. Shark teeth are probably the state's most common fossil. During the early Paleozoic era Texas was covered by a sea that would later be home to creatures like brachiopods, cephalopods, graptolites, and trilobites. Little is known about the state's Devonian and early Carboniferous life. Evidence indicates that during the late Carboniferous the state was home to marine life, land plants and early reptiles. During the Permian, the seas largely shrank away, but nevertheless coral reefs formed in the state. The rest of Texas was a coastal plain inhabited by early relatives of mammals like Dimetrodon and Edaphosaurus. During the Triassic, a great river system formed in the state that was inhabited by crocodile-like phytosaurs. Little is known about Jurassic Texas, but there are fossil aquatic invertebrates of this age like ammonites in the state. During the Early Cretaceous local large sauropods and theropods left a great abundance of footprints. Later in the Cretaceous, the state was covered by the Western Interior Seaway and home to creatures like mosasaurs, plesiosaurs, and few icthyosaurs. Early Cenozoic Texas still contained areas covered in seawater where invertebrates and sharks lived. On land the state would come to be home to creatures like glyptodonts, mammoths, mastodons, saber-toothed cats, giant ground sloths, titanotheres, uintatheres, and dire wolves. Archaeological evidence suggests that local Native Americans knew about local fossils. Formally trained scientists were already investigating the state's fossils by the late 1800s. In 1938, a major dinosaur footprint find occurred near Glen Rose. Pleurocoelus was the Texas state dinosaur from 1997 to 2009, when it was replaced by Sauroposeidon after the Texan fossils once referred to the former species were reclassified to a new genus.
A substantial amount of paleontological research has occurred within or conducted by people from the United States. Paleontologists have found that at the start of the Paleozoic era, what is now "North" America was actually in the southern hemisphere. Marine life flourished in the country's many seas. Later the seas were largely replaced by swamps, home to amphibians and early reptiles. When the continents had assembled into Pangaea drier conditions prevailed. The evolutionary precursors to mammals dominated the country until a mass extinction event ended their reign.
The geological history of North America comprises the history of geological occurrences and emergence of life in North America during the interval of time spanning from the formation of the Earth through to the emergence of humanity and the start of prehistory. At the start of the Paleozoic Era, what is now "North" America was actually in the Southern Hemisphere. Marine life flourished in the country's many seas, although terrestrial life had not yet evolved. During the latter part of the Paleozoic, seas were largely replaced by swamps home to amphibians and early reptiles. When the continents had assembled into Pangaea, drier conditions prevailed. The evolutionary precursors to mammals dominated the country until a mass extinction event ended their reign.
Mark Allen Norell is an American vertebrate paleontologist. He is currently the chairman of paleontology and a research associate at the American Museum of Natural History. He is best known as the discoverer of the first theropod embryo and for the description of feathered dinosaurs. Norell is credited with the naming of the genera Apsaravis, Byronosaurus, Citipati, Tsaagan, and Achillobator. His work regularly appears in major scientific journals and was listed by Time magazine as one of the ten most significant science stories of 1993, 1994 and 1996. Norell is both a fellow of the Explorer's Club and the Willi Hennig Society. He was featured in the fourth installment of Miracle Planet—a six-part documentary series that was released in 2005.
The Oulad Abdoun Basin is a phosphate sedimentary basin located in Morocco, near the city of Khouribga. It is the largest in Morocco, comprising 44% of Morocco's phosphate reserves, and at least 26.8 billion tons of phosphate. It is also known as an important site for vertebrate fossils, with deposits ranging from the Late Cretaceous (Cenomanian-Turonian) to the Eocene epoch (Ypresian), a period of about 25 million years.
Rukwatitan is a genus of titanosaur sauropod dinosaur from the Galula Formation in Tanzania. It lived around 100 million years ago, during the middle Cretaceous. The species, which shared features with another southern African species, Malawisaurus dixeyi, measured 30 feet (9.1 m) from the head to the tip of the tail, and had forelimbs that were estimated around 6.5 feet (2.0 m) long. Its fossils were found embedded in a cliff face near Lake Rukwa in the Rukwa Valley, from which it gets its name.
The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than 25 kg (55 lb) also became extinct, with the exception of some ectothermic species such as sea turtles and crocodilians. It marked the end of the Cretaceous period, and with it the Mesozoic era, while heralding the beginning of the current era, the Cenozoic. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, Fatkito boundary or K–T boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows unusually high levels of the metal iridium, which is more common in asteroids than in the Earth's crust.
Since the 19th century, a significant amount of research has been conducted on the Cretaceous–Paleogene extinction event, the mass extinction that ended the dinosaur-dominated Mesozoic Era and set the stage for the Age of Mammals, or Cenozoic Era. A chronology of this research is presented here.
Convolosaurus is a genus of basal ornithopod dinosaur from the Twin Mountains Formation from Proctor Lake in Comanche County, Texas. The type and only species is Convolosaurus marri.
References
- ↑ "Dinosaur hunters in and of Africa", The Complete Dinosaur by James O. Farlow and M. K. Brett-Surman, Indiana University Press, 1999, Pg. 47
- ↑ "Louis L. Jacobs" Archived 2010-12-31 at the Wayback Machine , SMU Biography
- ↑ "Jacobs named president", Geotimes, March 2000
- ↑ Jackson, David, "Detective work uncovers bones of dinosaurs", Dallas Morning News, November 22, 1993
- ↑ Lü, J.; Li, G; Kundrát, M.; Lee, Y.; Zhenyuan, S.; Yoshitsugu, K.; Caizhi, S.; Fangfang, T.; Hanfeng, L (2017). "High diversity of the Ganzhou Oviraptorid Fauna increased by a new "cassowary-like" crested species". Scientific Reports. 7 (1): 6393. doi:10.1038/s41598-017-05016-6. PMC 5532250 . PMID 28751667.
- ↑ "Dallas' Big Thinkers:Prof. Bonnie Jacobs and the 27-Million-Year-Old Pollen". www.smu.edu. Retrieved 2024-12-20.
- ↑ Mayou, Ellen, "Beyond Dinosaurs" Archived 2005-12-03 at the Wayback Machine , SMU Research, Volume 8, 2001
- ↑ "Quest for the African dinosaurs" by Louis L. Jacobs on Google Books
- ↑ "Evolution of Tertiary Mammals of North America" by Louis L. Jacobs on Google Books
