Open Paleo

Dysalotosaurus

Virchow, 1919 dis-a-LOHT-o-SOR-us

From Greek dysalotos (uncatchable) + sauros (lizard): 'uncatchable lizard'.

154.8–149.2 million years ago Kimmeridgian, Late Jurassic
Late Jurassic stages

Dysalotosaurus is a genus of herbivorous iguanodontian dinosaur. It was a dryosaurid iguanodontian, and its fossils have been found in late Kimmeridgian-age rocks (Late Jurassic) of the Tendaguru Formation of Lindi Region in Tanzania. The type and only species of the genus is D. lettowvorbecki. This species was named by Hans Virchow in 1919 in honor of the Imperial German Army Officer, Paul von Lettow-Vorbeck. For much of the 20th century the species was referred to the related and approximately contemporary genus Dryosaurus, but newer studies reject this synonymy.

Species

Dysalotosaurus lettowvorbecki Virchow, 1919

Type species

Named for Paul von Lettow-Vorbeck, Imperial German Army officer, by Hans Virchow in 1919.

Type specimen
Not catalogued , Museum für Naturkunde, Berlin (unknown)
Material
An axis (epistropheus) and an associated third cervical vertebra.
Notes
No holotype was designated; the genus was established on the cervical vertebrae described by Virchow (1919).
Horizon
Middle Dinosaur Member, Tendaguru Formation, Kimmeridgian, Late Jurassic , 154.8–149.2 million years ago
Locality
Tendaguru Quarry Ig, Kindope, Lindi, Tanzania

Notable specimens

  • GPIT-PV-122984

    Institut für Geowissenschaften, Universität Tübingen (English: Institute for Geosciences, Tübingen University) / Institut und Museum für Geologie und Paläontologie der Universität Tübingen ontogeny

    Semi-articulated juvenile (age 4–5 years) preserving ~40 associated elements, including cranial bones and a near-complete cervical series. Neurocentral sutures, closed in the cervicals but open in posterior dorsals, reveal a cervical fusion locus challenging the 'tail-to-head' model in Ornithopoda.

    Rocchi et al. (2026)

  • MB.R.1617

    Museum für Naturkunde, Berlin pathology

    An isolated presacral centrum co-ossified with a hemivertebra, producing about 35 degrees of kyphosis and 15 degrees of scoliosis. Interpreted as forming early in embryogenesis via hemimetameric segmental shift, it is one of few hemivertebrae documented in fossil vertebrates.

    Witzmann et al. (2008)

  • MB.R.1336

    Museum für Naturkunde, Berlin pathology

    A vertebral body showing macroscopic enlargement and, on micro-CT, the characteristic radiologic triad of Paget disease of bone in its mixed phase (trabecular coarsening, cortical thickening, and increased bone size). It is the oldest reported case of Paget disease in the fossil record.

    Witzmann et al. (2011)

References

  1. Virchow, H. (1919). Atlas und Epistropheus bei den Schildkröten [Atlas and axis in the turtles]. Sitzungsberichte der Gesellschaft Naturforschender Freunde zu Berlin 1919(8): 303-332. virchow1919a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026a
  3. Rocchi, R.; Rotatori, F. M.; Ferreira, G. S.; Fanti, F. (2026). An exquisitely preserved young iguanodontian from the Upper Jurassic of Tanzania sheds light on skeletal fusion patterns within Archosauria. Papers in Palaeontology 12(3): e70085. Wiley. doi:10.1002/spp2.70085 rocchi2026a
  4. Witzmann, F.; Asbach, P.; Remes, K.; Hampe, O.; Hilger, A.; Paulke, A. (2008). Vertebral pathology in an ornithopod dinosaur: a hemivertebra in Dysalotosaurus lettowvorbecki from the Jurassic of Tanzania. The Anatomical Record 291(9): 1149-1155. doi:10.1002/ar.20734

    Describes a pathological hemivertebra referred to Dysalotosaurus.

    witzmann2008a
  5. Witzmann, F.; Claeson, K. M.; Hampe, O.; Wieder, F.; Hilger, A.; Manke, I.; Niederhagen, M.; Rothschild, B. M.; Asbach, P. (2011). Paget disease of bone in a Jurassic dinosaur. Current Biology 21(17): R647-R648. doi:10.1016/j.cub.2011.08.006

    Reports Paget disease of bone in a referred Dysalotosaurus vertebra.

    witzmann2011a
  6. Bussert, R.; Heinrich, W. D.; Aberhan, M. (2009). The Tendaguru Formation (Late Jurassic to Early Cretaceous, southern Tanzania): definition, palaeoenvironments, and sequence stratigraphy. Fossil Record 12(2): 141-174. doi:10.5194/fr-12-141-2009

    Renames the Saurian Beds as formal members of the Tendaguru Formation, listing this taxon from the Middle Dinosaur Member.

    bussert2009a