Dromaeosauroides


Dromaeosauroides is a genus of dromaeosaurid theropod dinosaur from the Early Cretaceous of what is now Denmark and possibly also England. It was discovered in the Jydegaard Formation in the Robbedale valley, on the island of Bornholm in the Baltic Sea. This is the only likely place for dinosaur remains to be discovered on Danish territory, since the Mesozoic deposits exposed in the rest of the country are marine. Dromaeosauroides is the first known dinosaur from this location, and the only one which has been scientifically named. It is one of the oldest known dromaeosaurs in the world, and the first known uncontested dromaeosaur from the Early Cretaceous of Europe.

It is known from two teeth, the first of which was found in 2000 and the second in 2008. Based on the first tooth (the holotype), the genus and species Dromaeosauroides bornholmensis was named in 2003. The genus name means "Dromaeosaurus-like", due to the similarity to the teeth of that genus, and the species name means "from Bornholm". After this discovery, remains and tracks of more dinosaurs were found in several formations on Bornholm. Some teeth from the United Kingdom that have been referred to the genus Nuthetes may also belong to this animal. Coprolites containing fish remains found in the Jydegaard Formation may belong to Dromaeosauroides.

The holotype tooth is 21.7 millimetres (0.85 in) long, and the second tooth is 15 millimetres (0.59 in). They are curved and finely serrated. In life, Dromaeosauroides would have been 2 to 3 metres (7 to 10 ft) in length, and weighed about 40 kilograms (88 lb). As a dromaeosaur it would have been feathered, and had a large sickle claw on its feet like its relatives Dromaeosaurus and Deinonychus. It lived in a coastal lagoon environment with sauropods, as evidenced by a possible titanosaur tooth.

Few dinosaur remains have been found in Scandinavia. The mainland of western Denmark is an unlikely region to find dinosaur remains, since the Mesozoic sediments there are marine Maastrichtian chalk. Fossils of non-dinosaurian marine animals, including mosasaurs and plesiosaurs, have been found in these deposits.[1] Mesozoic deposits in Scania, Sweden, are much richer in fossils, including those of dinosaurs. The Danish island of Bornholm in the Baltic Sea was part of the same land mass as Scania (the Scandinavian-Russian continent), and has a similar geology. The southwestern part of the island is the only place in Denmark which has yielded dinosaur remains.[2]

During the 1990s, the Fossil Project (disbanded in 2005) was formed by a group of unemployed people who received funding from Denmark and the EEC to maintain geological sites on Bornholm.[2] One of these, "Carl Nielsen's sandpit" in the Robbedale valley (not to be confused with the Robbedale Formation, where no vertebrate remains have been found), is part of the Jydegaard Formation. This formation is 140 million years old, dating to the Late Berriasian (or Ryazanian) stage of the Early Cretaceous period. The Fossil Project sifted sand at these sites in cooperation with the NaturBornholm interpretation centre, which exhibited the fossils discovered. In September 2000, Danish palaeontologists Per Christiansen and Niels Bonde taught a field course at the site, "The Hunt for Danish Dinosaurs". During the course, geology student Eliza Jarl Estrup found a theropod tooth, the first dinosaur discovered on Danish territory, and the find was recorded by a local television station.[1][3]