Open Paleo

Dromaeosauroides

Christiansen & Bonde, 2003 DROH-mee-o-sor-ROY-deez

From Dromaeosaurus + Greek -oides, 'resembling'; means 'resembling Dromaeosaurus', indicating its morphological similarity to that genus

143.1–137.1 million years ago Berriasian, Early Cretaceous
Early Cretaceous stages

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 formation ranges from the Berriasian to the Valanginian ages. 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 Denmark, 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.

Under dispute

Dromaeosauroides bornholmensis is based on isolated tooth crowns, and its diagnosability has been debated. Weishampel and colleagues (2004) and Lindgren and colleagues (2008) regarded the holotype as indeterminate, but Bonde (2012) rebutted this — arguing that the teeth differ from those of other Early Cretaceous dromaeosaurids and of Dromaeosaurus, and that the earlier critiques rested on incorrect stratigraphic information — and retained the taxon as valid. Longrich and colleagues (2022) treated it as a possible early eudromaeosaur. It is retained as a valid, if tooth-based, dromaeosaurid.

Diagnosis

  1. Tooth crown recurved but not markedly blade-like, with a fore and aft basal length/basal width ratio of around 1.5
  2. Mesial and distal carinae both facing medially
  3. Both carinae finely serrate, with around 31 denticles per 5 mm on the mesial carina and around 30 per 5 mm on the distal carina, denticle size difference index of around 1
  4. Denticles around 0.15 mm in height, squarish and chisel-like in appearance, not anteriorly hooked

Species

Dromaeosauroides bornholmensis Christiansen & Bonde, 2003

Type species

Named for Bornholm, the Danish island where the holotype tooth was discovered.

Holotype
MGUH 27218 , Statens Naturhistoriske Museum (SNM), Københavns Universitet
Material
An anterior dentary tooth
Notes
Also cited in the literature under the alternate number DK 315.
Horizon
lower Tornhöj Member, Jydegaard Formation, Berriasian, Early Cretaceous , 143.1–137.1 million years ago
Locality
Carl Nielsen's sandpit, Capital Region of Denmark, Denmark Lindgren and colleagues (2008) date the beds as "deposited during late Berriasian time". Christiansen and Bonde (2003) give "Late Berriasian to ?Early Valanginian", with the Valanginian queried.

References

  1. Christiansen, P.; Bonde, N. (2003). The first dinosaur from Denmark. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 227(2): 287-299. Schweizerbart. doi:10.1127/njgpa/227/2003/287

    Erected Dromaeosauroides bornholmensis on an isolated tooth crown from the Jydegaard Formation of Bornholm.

    christiansen2003a
  2. Lindgren, J.; Currie, P. J.; Rees, J.; Siverson, M.; Lindström, S.; Alwmark, C. (2008). Theropod dinosaur teeth from the lowermost Cretaceous Rabekke Formation on Bornholm, Denmark. Geobios 41(2): 253-262. doi:10.1016/j.geobios.2007.05.001

    Regarded the Dromaeosauroides holotype tooth as indeterminate.

    lindgren2008a
  3. Bonde, N. (2012). Danish Dinosaurs: A Review. Bernissart Dinosaurs and Early Cretaceous Terrestrial Ecosystems (Godefroit, P., ed.) 435-449. Indiana University Press, Bloomington.

    Rebutted the indeterminacy claim and retained Dromaeosauroides as a valid taxon, noting the teeth differ from other Early Cretaceous dromaeosaurids.

    bonde2012a
  4. Longrich, N. R.; Martill, D. M.; Jacobs, M. L. (2022). A new dromaeosaurid dinosaur from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, and implications for European palaeobiogeography. Cretaceous Research 134. Elsevier BV. doi:10.1016/j.cretres.2021.105123

    Treated Dromaeosauroides as a possible early eudromaeosaur.

    longrich2022a
  5. Weishampel, D. B.; Dodson, P.; Osmólska, H. (eds.) (2004). The Dinosauria, Second Edition. University of California Press, Berkeley. weishampel2004a