Hylaeosaurus
genus of reptiles (fossil)
Hylaeosaurus ( hy-LEE-o-SOR-əs) is a herbivorous ankylosaurian dinosaur that lived about 136 million years ago, in the late Valanginian stage of the early Cretaceous period of England. It was found in the Grinstead Clay.
Hylaeosaurus was one of the first dinosaurs to be discovered, in 1832 by Gideon Mantell. In 1842 it was one of the three dinosaurs Richard Owen based the Dinosauria on, the others being Iguanodon and Megalosaurus. Four species were named in the genus, but only the type species Hylaeosaurus armatus is today considered valid. Only limited remains have been found of Hylaeosaurus and much of its anatomy is unknown. It might have been a basal nodosaurid, although a recent cladistic analysis recovers it as a basal ankylosaurid.
Hylaeosaurus was about five metres long. It was an armoured dinosaur that carried at least three long spines on its shoulder.
History of discovery
The first Hylaeosaurus fossils were discovered in the Grinstead Clay, West Sussex.
This brief starts where responsible research should: with the source description of “Hylaeosaurus” as genus of reptiles (fossil). Everything that follows is an evidence route, not borrowed authority.
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The subject matters to the science & nature register because the source frames it as genus of reptiles (fossil). Its deeper value depends on whether names, dates, institutions and citations support that framing.
Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated Aug 11, 2026. The linked authority identifier is Q131770. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1832 and 1842.
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This entry incorporates text from “Hylaeosaurus” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.