Diplodocoidea is a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like Supersaurus, Diplodocus, Apatosaurus, and Amphicoelias. Most had very long necks and long, whip-like tails; however, one family (the dicraeosaurids) are the only known sauropods to have re-evolved a short neck, presumably an adaptation for feeding low to the ground. This adaptation was taken to the extreme in the highly specialized sauropod Brachytrachelopan. A study of snout shape and dental microwear in diplodocoids showed that the square snouts, large proportion of pits, and fine subparallel scratches in Apatosaurus, Diplodocus, Nigersaurus, and Rebbachisaurus suggest ground-height nonselective browsing; the narrow snouts of Dicraeosaurus, Suuwassea, and Tornieria and the coarse scratches and gouges on the teeth of Dicraeosaurus suggest mid-height selective browsing in those taxa.[1] This taxon is also noteworthy because diplodocoid sauropods had the highest tooth replacement rates of any vertebrates, as exemplified by Nigersaurus, which had new teeth erupting every 30 days.


The below taxonomy follows the study of Emanuel Tschopp, Octavio Mateus and Roger Benson, 2015:

  • Diplodocoidea
    • Haplocanthosaurus
    • Diplodocimorpha
    • Rebbachisauridae
      • Flagellicaudata
        • Dicraeosauridae
        • Diplodocidae
          • Amphicoelias
          • Apatosaurinae
          • Diplodocinae

The phylogenetics of Diplodocoidea were reviewed in 2015 with a specimen-level phylogenetic analysis, as well as a species-level analysis. Their cladistic analysis is shown below.


Haplocanthosaurus priscus


Zapalasaurus bonapartei


Cathartesaura anaerobica

Limaysaurus tessonei


Nigersaurus taqueti

Demandasaurus darwini


Dyslocosaurus polyonychius

Suuwassea emilieae

Dystrophaeus viaemalae

Brachytrachelopan mesai

Amargasaurus cazaui

Dicraeosaurus hansemanni


Amphicoelias altus


?Apatosaurinae gen. et sp. nov.

Apatosaurus ajax

Apatosaurus louisae

Brontosaurus excelsus

Brontosaurus yahnahpin

Brontosaurus parvus


?Diplodocinae gen. et sp. nov.

Tornieria africana

Supersaurus lourinhanensis

Supersaurus vivianae

Leinkupal laticauda

Galeamopus hayi

Diplodocus carnegiei

Diplodocus hallorum

Kaatedocus siberi

Barosaurus lentus


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