CLASSIFICATION
| PARENT CLADES: Animalia: Vertebrata: Tetrapoda: Sauropsida: Archosauromorpha CLADOGRAM:–Macronaria Wilson & Sereno “large nares” == {Saltasaurus > Diplodocus} | INCERTAE SEDIS: | ?unnamed form ( (juvenile): specimens) — Late Jurassic — Germany | ?Abrosaurus | Bashunosaurus | Chondrosteosaurus | Sugiyamasaurus `–Camarasauromorpha “Camarasaurus forms” == {Camarasaurus + Saltasaurus} |–Camarasauridae | |?-Aragosaurus | |–Camarasaurus | `?-Lourinhasaurus `–Titanosauriformes “Titanosaurus forms” == {Titanosaurus + Brachiosaurus} | INCERTAE SEDIS: | indeterminate material (femur) — Maastrichtian — Egypt | ?indeterminate material (QM F6142: partial cervical vertebra) — Early Cretaceous — Australia | cf. Pleurocoelus — Albian to early Cenomanian — Africa | unnamed form — England | unnamed Ruby Ranch form (bones from at least 4 individuals) — Early Cretaceous — U.S.A. | ?Austrosaurus | ?Bellusaurus | Bothriospondylus | ?Damalasaurus | “Ischyrosaurus“ | Ornithopsis | Pelorosaurus | Venenosaurus |?-Astrodon |?-Atlasaurus |?-Eucamerotus |?-Pleurocoelus |–Sonorasaurus |–Brachiosauridae | |–Brachiosaurus | |–Cedarosaurus | |–Giraffatitan | `–Sauroposeidon `—->Titanosauria | ALTERNATE CLADOGRAM:–Macronaria |–Haplocanthosaurus `–Camarasauromorpha |–Camarasaurus `–Titanosauriformes |–Brachiosauridae `–Somphospondyli == {Saltasaurus + Euhelopus} |–Euhelopus `–Titanosauria ALTERNATE CLADOGRAM:–+–+–Haplocanthosaurus | `–Andesaurus `–Titanosauroidea sensu Sanz, J. Powell, Le Loeuff, Martinez & Pereda-Suberbiola, 1999 |–Opisthocoelicaudia `–Titanosauria sensu Sanz, J. Powell, Le Loeuff, Martinez & Pereda-Suberbiola, 1999 |
see also: Genus Index, Classification
ESSAY
| The name Macronaria (“large nostrils”) refers to the enlarged nasal openings of this group. Like all sauropods, their nostrils were situated atop their head, nearly above the eyes. Macronarians had crests of varying sizes formed by high nasal bones. In some specimens, these bones were not completely preserved, leaving the skull looking rather low, like those of diplodocimorphs. For this reason, many were once classified with them. “CAMARASAURS”:Basal (non-titanosauriform) macronarians, or “camarasaurs”, were fairly typical sauropods of small to average size. They had boxy skulls and spatulate teeth. Embryonic “camarasaur” material indicates that some laid eggs with diameters of 24 cm. “BRACHIOSAURS”:Most of the animals listed above as non-titanosaurian titanosauriforms have been included at some time in the family Brachiosauridae, but their exact relations to one another are poorly understood at this time. Among these animals are some of the largest land animals of all time, such as Brachiosaurus, Giraffatitan, and the new Sauroposeidon. Some had very high nasal crests and forelimbs longer than hindlimbs. It was once thought that the large crest of “brachiosaurs” was a snorkeling device. Since then it has been shown that if a Brachiosaurus were to be submerged at such a depth as to need a raised blowhole on its head, the pressure on its chest would be so great that its lungs would collapse. Instead, it is likely that “brachiosaurs”, and probably all sauropods, were terrestrial. |
