Dicraeosaurus hansemanni

Dicraeosaurus hansemanni was a medium-sized sauropod from the Late Jurassic Tendaguru ecosystem of southern Tanzania. Unlike the extremely long-necked diplodocids, it carried a relatively short, muscular neck above a compact body and long tail. Tall neural spines split into paired prongs along the neck and back, giving the genus its name and anchoring powerful ligaments and muscles. Material collected during the German Tendaguru Expedition includes the exceptionally informative partial skeleton known as 'm', together with additional bones that make Dicraeosaurus one of the best-understood dicraeosaurids. The original fossils remain mounted in Berlin, while ongoing work is re-evaluating whether all Tendaguru material assigned to two Dicraeosaurus species is truly distinct.

Its fossils occur between approximately 155 and 150 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The skull was small and low, with peg-like teeth concentrated toward the front of the jaws. The neck was short for a sauropod and supported by deeply forked neural spines, which continued along the front of the back. A relatively high shoulder region, stout columnar limbs and compact trunk supported the body, while the long tapering tail balanced it. The exact outline of soft tissue above the split spines is unknown; they probably anchored ligaments and muscles rather than a tall sail.

• Relatively short neck for a diplodocoid sauropod
• Tall paired neural spines along the neck and front of the back
• Small low skull with narrow peg-like teeth
• Compact torso and robust shoulder region
• Four columnar limbs supporting a medium-sized sauropod body
• Long tapering tail without the extreme whip-like proportions of diplodocids

Fossils assigned to Dicraeosaurus were excavated around Tendaguru Hill during the German Tendaguru Expedition of 1909-1913, when Tanzania was under German colonial rule. Werner Janensch named D. hansemanni in 1914 and honoured pathologist David Paul von Hansemann, whose support helped launch the expedition. The Museum für Naturkunde Berlin later mounted the best-preserved skeleton 'm'. Modern research is digitally scanning the skull, neck and shoulder and reassessing the historic species diagnoses, while the museum also documents the collection's colonial history and Tanzanian restitution claims.

Discovery credit: German Tendaguru Expedition field teams.

Naming authors: Werner Janensch.

The Tendaguru Formation records coastal plains, river channels, lagoons and seasonally dry environments near the Jurassic coast of eastern Africa. Dicraeosaurus shared this landscape with Giraffatitan, Tornieria, Kentrosaurus, Dysalotosaurus and theropod predators. The displayed map point represents the broad Tendaguru fossil region, not an individual excavation trench.

Dicraeosaurus was a low-to-middle browser that cropped vegetation with narrow teeth and swallowed it with little oral processing. Its shorter neck probably favoured a different feeding envelope from the taller Giraffatitan living in the same formation. Biomechanical work continues to test how far the neck could move. Direct evidence for herd size, nesting, migration or defensive behaviour is not known.

• Its name means forked lizard because the neural spines divide into paired prongs.
• The mounted Berlin skeleton includes some of the most complete original dicraeosaurid material known.
• It lived beside the much taller Giraffatitan in the Tendaguru ecosystem.
• Modern researchers are scanning the historic fossils to rebuild the neck and shoulder muscles digitally.
• Its fossils are also part of ongoing discussions about colonial collecting and restitution between Germany and Tanzania.

A research repository is not necessarily a public exhibit. Loan and display status can change, so check with the institution before visiting.

1. 01
   Dicraeosaurus hansemanni Janensch 1914

   Holger Stoecker, Michael Ohl · Taxonomies at Tendaguru: How the Berlin Dinosaurs Got Their Names · 2024

   Open source
2. 02
   Dicraeosaurus: The story of M and m

   Museum für Naturkunde Berlin

   Open source
3. 03
   Virtual access to fossil and archival material from the German Tendaguru Expedition

   Museum für Naturkunde Berlin

   Open source