page_title: Baryonyx
section_title: History of discovery
hierarchical_section_title: Baryonyx / History of discovery
caption_attribution_description: English: Skeleton of a Baryonyx dinosaur Deutsch: Skelett eines Baryonyx Dinosauriers
context_page_description: 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 Baryonyx 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 its discovery attracted media attention. Specimens later discovered in other parts of the United Kingdom and Iberia have also been assigned to the genus.
  The holotype specimen, which may not have been fully grown, was estimated to have been between 7.5 and 10 metres long and to have weighed between 1.2 and 1.7 metric tons. Baryonyx had a long, low, and narrow snout, which has been compared to that of a gharial. The tip of the snout expanded to the sides in the shape of a rosette.
context_section_description: In January 1983 the British plumber and amateur fossil collector William J. Walker explored the Smokejacks Pit, a clay pit in the Weald Clay Formation near Ockley in Surrey, England. He found a rock wherein he discovered a large claw, but after piecing it together at home, he realised the tip of the claw was missing. Walker returned to the same spot in the pit some weeks later, and found the missing part after searching for an hour. He also found a phalanx bone and part of a rib. Walker's son-in-law later brought the claw to the Natural History Museum of London, where it was examined by the British palaeontologists Alan J. Charig and Angela C. Milner, who identified it as belonging to a theropod dinosaur. The palaeontologists found more bone fragments at the site in February, but the entire skeleton could not be collected until May and June due to weather conditions at the pit. A team of eight museum staff members and several volunteers excavated 2 metric tons (2.2 short tons; 2.0 long tons) of rock matrix in 54 blocks over a three-week period. Walker donated the claw to the museum, and the Ockley Brick Company (owners of the pit) donated the rest of the skeleton and provided equipment.  The area had been explored for 200 years, but no similar remains had been found before.
  Most of the bones collected were encased in siltstone nodules surrounded by fine sand and silt, with the rest lying in clay. The bones were disarticulated and scattered over a 5-by-2-metre (16.4-by-6.6-foot) area, but most were not far from their natural positions. The position of some bones was disturbed by a bulldozer, and some were broken by mechanical equipment before they were collected. Preparing the specimen was difficult, due to the hardness of the siltstone matrix and the presence of siderite; acid preparation was attempted, but most of the matrix was removed mechanically. It took six years of almost constant preparation to get all the bones out of the rock, and by the end, dental tools and air mallets had to be used under a microscope. The specimen represents about 65 percent of the skeleton, and consists of partial skull bones, including premaxillae (first bones of the upper jaw); the left maxillae (second bone of the upper jaw); both nasal bones; the left lacrimal; the left prefrontal; the left postorbital; the braincase including the occiput; both dentaries (the front bones of the lower jaw); various bones from the back of the lower jaw; teeth; cervical (neck), dorsal (back), and caudal (tail) vertebrae; ribs; a sternum; both scapulae (shoulder blades); both coracoids; both humeri (upper arm bones); the left radius and ulna (lower arm bones); finger bones and unguals (claw bones); hip bones; the upper end of the left femur (thigh bone) and lower end of the right; right fibula (of the lower leg); and foot bones including an ungual. The original specimen number was BMNH R9951, but it was later re-catalogued as NHMUK VP R9951.
   
  In 1986, Charig and Milner named a new genus and species with the skeleton as holotype specimen: Baryonyx walkeri. The generic name derives from ancient Greek; βαρύς (barys) means "heavy" or "strong", and ὄνυξ (onyx) means "claw" or "talon". The specific name honours Walker, for discovering the specimen. At that time, the authors did not know if the large claw belonged to the hand or the foot (as in dromaeosaurs, which it was then assumed to be). The dinosaur had been presented earlier the same year during a lecture at a conference about dinosaur systematics in Drumheller, Canada. Due to ongoing work on the bones (70 percent had been prepared at the time), they called their article preliminary and promised a more detailed description at a later date. Baryonyx was the first large Early Cretaceous theropod found anywhere in the world by that time. Before the discovery of Baryonyx the last significant theropod find in the United Kingdom was Eustreptospondylus in 1871, and in a 1986 interview Charig called Baryonyx "the best find of the century" in Europe. Baryonyx was widely featured in international media, and was nick
caption: Reconstructed skeleton based on the holotype specimen, Natural History Museum, London
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