Where were the first Baryonyx fossils found?
2899822#11
In 1983, a relatively complete skeleton was excavated from the Smokejacks pit in Surrey, Engand. These remains were described by British paleontologists Alan J. Charig and Angela C. Milner in 1986 as the holotype of a new species, "Baryonyx walkeri." After the discovery of "Baryonyx," many new genera have since been described, the majority on very incomplete remains. However, other finds bear enough fossil material and distinct anatomical features to be assigned with confidence. Paul Sereno and colleagues described "Suchomimus" in 1998"," a baryonychine from Niger on the basis of a partial skeleton found in 1997. Later in 2004, partial jaw bones were recovered from the Alcântara Formation, these were referred to a new genus of spinosaurine named "Oxalaia" in 2011 by Alexander Kellner.
Spinosauridae
1091918#0
Baryonyx () is a genus of theropod dinosaur which lived in the Barremian stage of the Early Cretaceous Period, about 130–125 million years ago. The first skeleton was discovered in 1983 in the Weald Clay Formation of Surrey, England, and became the holotype specimen of B. walkeri, named by palaeontologists Alan J. Charig and Angela C. Milner in 1986. The generic name, "Baryonyx", means "heavy claw" and alludes to the animal's very large claw on the first finger; the specific name, "walkeri", refers to its discoverer, amateur fossil collector William J. Walker. The holotype specimen is one of the most complete theropod skeletons from the UK (and remains the most complete spinosaurid), and its discovery attracted media attention. Specimens later discovered in other parts of the United Kingdom and Iberia have also been assigned to the genus.
Baryonyx
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Baryonychines have been found in Africa, with "Suchomimus" and "Cristatusaurus," as well as in Europe, with "Baryonyx" and "Suchosaurus". "Baryonyx-"like teeth are also reported from the Ashdown Sands of Sussex, in England, and the Burgos Province, in Spain. A partial skeleton and many fossil teeth indicate spinosaurids were widespread in Asia. As of 2012, three have been named: "Ichthyovenator," "Siamosaurus" and ""Sinopliosaurus" fusuiensis". In 2014, a spinosaurid tooth was discovered in Malaysia; the first dinosaur remains discovered in the country. At la Cantalera-1, a site in the Early Barremanian Blesa Formation in Treul, Spain, two types of spinosaurid teeth were found, and they were assigned, tentatively, as indeterminate spinosaurine and baryonychine taxa. An intermediate spinosaurid was discovered in the Early Cretaceous Eumeralla Formation, Australia. It is known from a single 4 cm long partial cervical vertebra, designated NMV P221081. It is missing most of the neural arch. The specimen is from a juvenile estimated to be about 2 to 3 meters long (6–9 ft). Out of all spinosaurs it most closely resembles "Baryonyx".
Spinosauridae
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Direct fossil evidence shows that spinosaurids fed on fish as well as a variety of other small to medium-sized animals, including dinosaurs. "Baryonyx" was found with scales of the prehistoric fish "Scheenstia" in its body cavity, and these were abraded, hypothetically by gastric juices. Bones of a young "Iguanodon", also abraded, were found alongside this specimen. If these represent "Baryonyx"’s meal, the animal was, whether in this case a hunter, or a scavenger, an eater of more diverse fare than fish. Moreover, there is a documented example of a spinosaurid having eaten a pterosaur, as one "Irritator" tooth was found embedded within the fossil vertebrae of an ornithocheirid pterosaur found in the Romualdo Formation of Brazil. This may represent a predation or a scavenging event. In the Sao Khua Formation of Thailand, isolated tooth crowns from "Siamosaurus" have been found in association with sauropod remains, indicating possible predation or scavenging.
Spinosauridae
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In 1997, Charig and Milner noted that two fragmentary spinosaurid snouts from the Elrhaz Formation of Niger (reported by the French palaeontologist Philippe Taquet in 1984) were similar enough to "Baryonyx" that they considered them to belong to an indeterminate species of the genus (despite their much younger Aptian geological age). In 1998, these fossils became the basis of the genus and species "Cristatusaurus lapparenti", named by Taquet and the American palaeontologist Dale Russell. The American palaeontologist Paul Sereno and colleagues named the new genus and species "Suchomimus tenerensis" later in 1998, based on more complete fossils from the Elrhaz Formation. In 2002, the German palaeontologist Hans-Dieter Sues and colleagues proposed that "Suchomimus tenerensis" was similar enough to "Baryonyx walkeri" to be considered a species within the same genus (as "B. tenerensis"), and that "Suchomimus" was identical to "Cristatusaurus". Milner concurred that the material from Niger was indistinguishable from "Baryonyx" in 2003. In a 2004 conference abstract, Hutt and Newberry supported the synonymy based on a large theropod vertebra from the Isle of Wight which they attributed to an animal closely related to "Baryonyx" and "Suchomimus". Later studies have kept "Baryonyx" and "Suchomimus" separate, whereas "Cristatusaurus" has been proposed to be either a "nomen dubium" or possibly distinct from both. A 2017 review paper by the Brazilian palaeontologist Carlos Roberto A. Candeiro and colleagues stated that this debate was more in the realm of semantics than science, as it is generally agreed that "B. walkeri" and "S. tenerensis" are distinct, related species.
Baryonyx
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Discoveries in the 1990s shed more light on the relationships of "Baryonyx" and its relatives. In 1996, a snout from Morocco was referred to "Spinosaurus", and "Irritator" and "Angaturama" from Brazil (the two are possible synonyms) were named. "Cristatusaurus" and "Suchomimus" were named based on fossils from Niger in 1998. In their description of "Suchomimus", Sereno and colleagues placed it and "Baryonyx" in the new subfamily Baryonychinae within Spinosauridae; "Spinosaurus" and "Irritator" were placed in the subfamily Spinosaurinae. Baryonychinae was distinguished by the small size and larger number of teeth in the dentary behind the terminal rosette, the deeply keeled front dorsal vertebrae, and by having serrated teeth. Spinosaurinae was distinguished by their straight tooth crowns without serrations, small first tooth in the premaxilla, increased spacing of teeth in the jaws, and possibly by having their nostrils placed further back and the presence of a deep neural spine sail. They also united the spinosaurids and their closest relatives in the superfamily Spinosauroidea, but in 2010, the British palaeontologist Roger Benson considered this a junior synonym of Megalosauroidea (an older name). In a 2007 conference abstract, the American palaeontologist Denver W. Fowler suggested that since "Suchosaurus" is the first named genus in its group, the clade names Spinosauroidea, Spinosauridae, and Baryonychinae should be replaced by Suchosauroidea, Suchosauridae, and Suchosaurinae, regardless of whether or not the name "Baryonyx" is retained. A 2017 study by the Brazilian palaeontologists Marcos A. F. Sales and Cesar L. Schultz found that the clade Baryonychinae was not well supported, since serrated teeth may be an ancestral trait among spinosaurids.
Baryonyx
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In 2016, the Spanish palaeontologist Alejandro Serrano-Martínez and colleagues reported the oldest known spinosaurid fossil, a tooth from the Middle Jurassic of Niger, which they found to suggest that spinosaurids originated in Gondwana, since other known Jurassic spinosaurid teeth are also from Africa, but they found the subsequent dispersal routes unclear. Candeiro and colleagues suggested in 2017 that spinosaurids of northern Gondwana were replaced by other predators, such as abelisauroids, since no definite spinosaurid fossils are known from after the Cenomanian anywhere in the world. They attributed the disappearance of spinosaurids and other shifts in the fauna of Gondwana to changes in the environment, perhaps caused by transgressions in sea level.
Baryonyx
261840#6
Many important fossils have been found in the sandstones and clays of the Weald, including, for example, "Baryonyx". The famous scientific hoax of Piltdown Man was claimed to have come from a gravel pit at Piltdown near Uckfield. The first "Iguanodon" was identified after a Mary Mantell unearthed some fossilised teeth by a road in Sussex in 1822. Her husband, Gideon Mantell, noticed they were similar to modern iguana teeth but many times larger; this important find led to the discovery of dinosaurs.
Weald
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Fossils from other parts of the UK and Iberia, mostly isolated teeth, have subsequently been attributed to "Baryonyx" or similar animals. Isolated teeth and bones from the Isle of Wight, including hand bones reported in 1998 and a vertebra reported by the British palaeontologists Steve Hutt and Penny Newbery in 2004, have been attributed to this genus. In 2017, the British palaeontologist Martin C. Munt and colleagues reported cranial remains of two "Baryonyx" individuals from the Isle of Wight, and stated they would be examined and described in the future. A maxilla fragment from La Rioja, Spain, was attributed to "Baryonyx" by the Spanish palaeontologists Luis I. Viera and José Angel Torres in 1995 (although the American palaeontologist Thomas R. Holtz and colleagues raised the possibility that it could have belonged to "Suchomimus" in 2004). In 1999, a postorbital bone, a squamosal bone, a tooth, vertebral remains, metacarpals, and a phalanx from the Sala de los Infantes deposit in Burgos Province, Spain, were attributed to an immature "Baryonyx" (though some of these elements are unknown in the holotype) by the Spanish palaeontologist Carolina Fuentes Vidarte and colleagues. Dinosaur tracks near Burgos have also been suggested to belong to "Baryonyx" or a similar theropod. In 2011, a specimen (ML1190) from the Papo Seco Formation in Boca do Chapim, Portugal, with a fragmentary dentary, teeth, vertebrae, ribs, hip bones, a scapula, and a phalanx bone, was attributed to "Baryonyx" by the Portuguese palaeontologist Octávio Mateus and colleagues, the most complete Iberian remains of the animal. The skeletal elements of this specimen are also represented in the more complete holotype (which was of similar size), except for the mid-neck vertebrae. In 2018, the British palaeontologist Thomas M. S. Arden and colleagues found that the Portuguese skeleton did not belong to "Baryonyx", since the front of its dentary bone was not strongly upturned. Some additional spinosaurid remains from Iberia appear to belong to taxa other than "Baryonyx".
Baryonyx
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Fossil remains of "Neovenator" have been found on the Isle of Wight off southern England, and were first discovered in the 20th century. "Neovenator" perhaps existed alongside other dinosaurs found in the Wessex Formation of the early Cretaceous period, such as "Baryonyx", "Polacanthus" and "Iguanodon". The holotype bones were mixed with those of the plant-eater "Mantellisaurus" and in the dig site also remains of fishes, amphibians, lizards, pterosaurs and Goniopholididae were present. "Neovenator" was one of the apex predators of its day.
Neovenator