Various Macronaria; Camarasaurus left ( brown), Brachiosaurus in the background ( gray), Giraffatitan in the middle ( yellow), Euhelopus in the foreground (green)

The Macronaria (Greek: " big noses " ) are a group of sauropod dinosaurs rich in forms. They include original forms such as Camarasaurus, Brachiosaurus and Euhelopus as well as the advanced Titanosauria. Thus they form the next Diplodocoidea the second core group of Neosauropoda.

  • 4.1 Literature
  • 4.2 Notes and references

Period and dissemination

The earliest undoubted representatives of Macronaria originate from the Upper Jurassic and close Brachiosaurus and related forms, Camarasaurus and the possible early Titanosauria Janenschia with a. As already in the Upper Jurassic occurred such a diverse Macronaria fauna, it is assumed that the origin of the group is already in the Middle Jurassic. This hypothesis is supported by finds of footprints from the Middle Jurassic, which probably belonged to representatives of Macronaria.

The last Macronaria belong to the group of Titanosauria and include, for example Opisthocoelicaudia and Alamosaurus with a. This species died out only at the mass extinction at the Cretaceous - Tertiary boundary in front of about 66 million years ago, along with all other non-avian dinosaurs. Thus the Macronaria were the last surviving group of sauropods.

Fossils of Macronaria were found on all continents, with the exception of Antarctica.


The limbs original Macronaria as Brachiosaurus and Euhelopus were longer than other sauropods. In addition, the forelimbs were relatively significantly extended to the rear legs, which is due to an elongated metacarpal among others. In the Brachiosaurus forelimbs were even longer than the hind legs. Thanks to these adjustments, there was the shoulder at a higher altitude, which is the maximum grazing height increased. These original Macronaria could therefore have been dedicated to higher ground food sources - in contrast to the Diplodocoidea that showed short front legs and thus a more deep-seated shoulder, which probably means that these sauropods recordings mainly low-growing vegetation.


Inside systematics

The Macronaria consists of two main groups: the family Camarasauridae and the clade Titanosauriformes. The Titanosauriformes is in turn divided into the Brachiosauridae and Titanosauria. From unclear position within the Macronaria is the genus Brontomerus.

  • Macronaria Abrosaurus
  • Family Camarasauridae Camarasaurus
  • Huanghetitan
  • Family Euhelopodidae Euhelopus







Outer systematics

The Macronaria is a clade within the Sauropoda. The sister taxon is the Diplodocoidea. The cladogram shows the phylogenetic relationships (simplified after Weishampel, Dodson and Osmólska, 2004):