Alexander Kellner | |
---|---|
Born | Alexander Wilhelm Armin Kellner September 26, 1961 |
Nationality | Brazilian |
Alma mater | Federal University of Rio de Janeiro Columbia University |
Known for | Pterosaurs, dinosaurs |
Scientific career | |
Fields | Paleontology, Geology |
Institutions | National Museum (Rio de Janeiro) |
Alexander Wilhelm Armin Kellner (born September 26, 1961) is a Brazilian geologist and paleontologist who is a leading expert in the field of studying pterosaurs. His research has focused mainly on fossil reptiles from the Cretaceous Period, including extinct dinosaurs and crocodylomorphs. [1]
Kellner has over 500 publications to his name, has published more than 160 primary studies and two science books. He has participated in paleontological expeditions to many locations including Brazil, Chile, Iran, the United States, Argentina, China, and Antarctica.
His scientific achievements include the description of more than thirty species. For his work he has received several honors and prizes, including the TWAS Prize for Earth Sciences from The World Academy of Sciences and admission to the National Order of Scientific Merit (class Comendador), one Brazil's most prestigious awards.
Kellner was born in Vaduz, Liechtenstein, son of a German father and Austrian mother. [2] In his early childhood he moved with his parents to Brazil, where he became naturalised Brazilian. [1]
In Rio de Janeiro he received a primary and secondary education at the bilingual Escola Alemã Corcovado. [1] He began studying geology at the Federal University of Rio de Janeiro (UFRJ) in 1981. As a student, he soon began researching fossil vertebrates, particularly reptiles from Brazil's Cretaceous Period. [1] His studies largely concerned pterosaur specimens from the geologic Santana Group, about which he published many papers in the late 1980s.[ citation needed ] He earned a Master of Science degree in geology at the UFRJ in 1991, a MPhil degree in 1994, and a Ph.D. in 1996 from Columbia University in New York, in a joint program with the American Museum of Natural History. In 1997 he became a professor at the Federal University-owned National Museum of Rio de Janeiro and curator of its geological and paleontological departments. From 1998 to 2001, he served as the chairman of these departments and has been head of the zoology graduate program since 2008. [1] Kellner is also chief editor of the Anais da Academia Brasileira de Ciências , the official publication of the Brazilian Academy of Sciences. [3]
As part of his work on flying reptiles, Kellner organised the Pterosaur Workshop at Pittsburgh, USA, in 1995, [4] and the first pterosaur symposium ever held at the American Museum of Natural History in 1996. As well, he was involved in the organisation of several scientific meetings in Rio de Janeiro such as the 31st International Geological Congress in 2000 and the 2nd Latin-American Congress of Vertebrate Paleontology in 2002. [1]
Kellner has organized or taken part in several paleontological expeditions to many locations around the globe, including Brazil—Mato Grosso, Rio Grande do Sul and Ceará; [5] the deserts of Atacama, Chile and Kerman, Iran; Montana in the United States; Patagonia in Argentina; [1] the famous deposits of Liaoning, China, [5] [6] and James Ross Island in Antarctica. [7] [8]
Kellner has over 500 publications to his name (including abstracts and science articles). He has published more than 160 primary studies [4] and two science books: Pterossauros - os senhores do céu do Brasil ("Pterosaurs — Lords of the Brazilian Sky") [9] and the novel Na terra dos titãs ("In the Land of the Titans"). [10] He has also taken part in documentaries about fossils (e.g., Antarctica - a Summer of 70 million Years and Dinosaur Hunters).[ citation needed ]
As a result of his scientific activity he has received several honours, being appointed a member of the Brazilian Academy of Sciences in 1997. He is also an honourable member of the New York Paleontologial Society and the Paleontological Society of Chile. He is a research associate of the American Museum of Natural History [1] and of the Chinese Institute of Vertebrate Paleontology and Paleoanthropology.[ citation needed ]
Besides his teaching activity, having advised over fifteen master and Ph.D. students, Kellner has been active in the propagation of scientific knowledge to the general public. He organised the 1999 exposition No Tempo dos Dinossauros ("In the Time of the Dinosaurs") at the Museum of Earth Sciences, which has been regarded as a landmark for the establishment of paleontology in Brazil, attracting the attention of the people of Brazilian to the studies of fossils. [1] In 2006 he organized the mounting of the first large-scale dinosaur skeleton in Brazil, that of the sauropod Maxakalisaurus topai, for which he received recognition from the Brazilian Congress. [5] [11] Since 2004 he has written a monthly column in Caçadores de Fósseis (Fossil Hunters), on the website Ciência Hoje On Line, a project of the Brazilian Society for Scientific Progress. [12]
Apart from studying their fossils, Kellner has performed important theoretical work on pterosaurs, including cladistic studies regarding their phylogeny. In this he is the founder of a distinctive Brazilian school of the study of pterosaurs, with its own favoured phylogenetic model, clade terminology and nomenclature. Rival models and nomenclatural choices have been devised by the influential British pterosaur researcher David Unwin.[ citation needed ]
Kellner has received numerous honours and prizes, including the TWAS Prize for Earth Sciences from The World Academy of Sciences. [13] He was admitted in the National Order of Scientific Merit (class Comendador), one the Brazilian Federal Government's most prestigious awards.
Kellner's scientific achievements include the description of more than thirty species, of which Santanaraptor placidus (1996, 1999) is among the best examples of soft tissue preservation, including blood vessels and muscle fibers, reported in any dinosaur. The pterosaur Thalassodromeus sethi, which Kellner described in 2002 with his colleague Diogenes de Almeida Campos, allowed for the establishment of a new hypothesis regarding the use of the head crest in body temperature regulation of pterosaurs. [1]
A complete list of new species described and named by Kellner, sometimes in cooperation with other researchers, includes:
Tapejara is a genus of Brazilian pterosaur from the Cretaceous Period. Tapejara crests consisted of a semicircular crest over the snout, and a bony prong which extended back behind the head. It was a small pterosaur, with a wingspan of approximately 1.23–1.3 metres (4.0–4.3 ft).
Cearadactylus is a genus of large anhanguerid pterodactyloid pterosaur from the Romualdo Formation of Brazil, South America. Fossil remains of Cearadactylus dated back to the Albian stage of the Early Cretaceous period, about 112 million years ago. The only known species is C. atrox, described and named in 1985 by Giuseppe Leonardi and Guido Borgomanero. The name refers to the Brazilian state Ceará, and combines this with Greek daktylos, "finger", a reference to the wing finger of pterosaurs. The Latin atrox means "frightful", a reference to the fearsome dentition of the species.
Tropeognathus is a genus of large pterosaurs from the late Early Cretaceous of South America. This genus is considered to be a member of the family Anhangueridae, however, several studies have also recovered it within another family called Ornithocheiridae. Both of these families are diverse groups of pterosaurs known for their keel-tipped snouts and large size. Tropeognathus is regarded as the largest pterosaur found in the Southern Hemisphere, only rivaled by the huge azhdarchids. The type and only species is Tropeognathus mesembrinus. Fossil remains of Tropeognathus have been recovered from the Romualdo Formation, which is a Lagerstätte located in the Santana Group of the Araripe Basin in northeastern Brazil.
Anhanguera is a genus of pterodactyloid pterosaur known from the Early Cretaceous Romualdo Formation of Brazil and the Late Cretaceous Kem Kem Group of Morocco. This pterosaur is closely related to Ornithocheirus, but belongs in the family Anhangueridae. The generic name comes from the Tupi words añanga, meaning "spirit protector of the animals" + wera "bygone".
Tapejaridae are a family of pterodactyloid pterosaurs from the Cretaceous period. Members are currently known from Brazil, England, Hungary, Morocco, Spain, the United States, and China. The most primitive genera were found in China, indicating that the family has an Asian origin.
Siroccopteryx is an extinct genus of anhanguerid pterodactyloid pterosaur, known from middle Cretaceous sediments in modern-day Morocco. Some researchers, such as David M. Unwin, consider the genus a junior synonym of Coloborhynchus.
Eopteranodon is a genus of tapejarid pterosaur from the Aptian-age Lower Cretaceous Yixian Formation of Beipiao City, Liaoning, China. The genus was named in 2005 by paleontologists Lü Junchang and Zhang Xingliao. The type species is Eopteranodon lii.
Feilongus is an extinct genus of ctenochasmatid pterodactyloid pterosaur from the Barremian–Aptian-age Lower Cretaceous Yixian Formation of Beipiao, Liaoning, China.
Gegepterus is a genus of ctenochasmatid pterosaur from the Early Cretaceous period of what is now the Yixian Formation of Liaoning, China. Only one species is known, G. changi.
Liaoxipterus is a genus of pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The type species is Liaoxipterus brachyognathus. The genus name is derived from the discovery locality Liaoxi and a Latinised Greek pteron, "wing". The specific name is derived from Greek brachys, "short" and gnathos, "jaw".
Sinopterus was a genus of tapejarid pterodactyloid pterosaur from the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. It was first described and named by Wang Xiaolin and Zhou Zhonghe. Three species have been classified in this genus, though only two are generally considered to be valid. Sinopterus is known for its proportionally large skull, which has a birdlike pointed beak, a long bony crest that starts with a tall premaxilla and goes back along the middle of the skull to form a point overhanging the rear of the skull, and its lack of teeth.
Jidapterus is a genus of chaoyangopterid pterosaur from the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The genus was in 2003 named by Dong Zhiming, Sun Yue-Wu and Wu Shao-Yuan. The type species is Jidapterus edentus. The genus name is derived from Jílín Dàxué or "Jilin University" and a Latinized Greek pteron, "wing". The specific name means "toothless" in Latin.
Ornithocheiridae is a group of pterosaurs within the suborder Pterodactyloidea. These pterosaurs were among the last to possess teeth. Members that belong to this group lived from the Early to Late Cretaceous periods, around 140 to 90 million years ago.
Hongshanopterus is a genus of pterodactyloid pterosaur from the Lower Cretaceous Jiufotang Formation of Liaoning, China.
Pteranodontoidea is an extinct clade of ornithocheiroid pterosaurs from the Early to Late Cretaceous of Asia, Africa, Europe, North America and South America. It was named by Alexander Wilhelm Armin Kellner in 1996. In 2003, Kellner defined the clade as a node-based taxon consisting of the last common ancestor of Anhanguera, Pteranodon and all its descendants. The clade Ornithocheiroidea is sometimes considered to be the senior synonym of Pteranodontoidea, however it depends on its definition. Brian Andres in his analyses, converts Ornithocheiroidea using the definition of Kellner (2003) to avoid this synonymy.
This timeline of pterosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of pterosaurs, the famed flying reptiles of the Mesozoic era. Although pterosaurs went extinct millions of years before humans evolved, humans have coexisted with pterosaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about thunderbirds told by the Native Americans of the modern Western United States may have been influenced by observations of Pteranodon fossils. These thunderbirds were said to have warred with water monsters, which agrees well with the co-occurrence of Pteranodon and the ancient marine reptiles of the seaway over which it flew.
Tapejaroidea is a group of pterosaurs belonging to the clade Ornithocheiroidea. Tapejaroids lived from the Early to Late Cretaceous periods, with one possible member, Tendaguripterus, extending the fossil range to the Late Jurassic period. Tapejaroidea contains two groups, the Dsungaripteridae and the Azhdarchoidea, which in turn includes the azhdarchids, the group that contains some of the largest flying animals. The group was named by Brazilian paleontologist Alexander Wilhelm Armin Kellner in 1996.
Ornithocheiromorpha is a group of pterosaurs within the suborder Pterodactyloidea. Fossil remains of this group date back from the Early to Late Cretaceous periods, around 140 to 92.5 million years ago. Ornithocheiromorphs were discovered worldwide except Antarctica, though most genera were recovered in Europe, Asia and South America. They were the most diverse and successful pterosaurs during the Early Cretaceous, but throughout the Late Cretaceous they were replaced by better adapted and more advanced pterosaur species such the pteranodontids and azhdarchoids. The Ornithocheiromorpha was defined in 2014 by Andres and colleagues, and they made Ornithocheiromorpha the most inclusive clade containing Ornithocheirus, but not Pteranodon.
Argentinadraco is an extinct genus of azhdarchoid pterosaur from the Late Cretaceous Portezuelo Formation of Argentina. It contains a single species, A. barrealensis, named in 2017 by Alexander Kellner and Jorge Calvo. Argentinadraco is unusual for bearing a bottom jaw with a concave bottom edge, as well as a pair of ridges and depressions on the top surface. These features distinguish it from all other azhdarchoid groups, complicating its assignment, but it may belong to the Chaoyangopteridae. The ridges on the lower jaw may have been used to feed on small invertebrates in loose sediment within the system of lakes and rivers that it resided in.