[1] The only species is Dinheirosaurus lourinhanensis, first described by José Bonaparte and Octávio Mateus in 1999 for vertebrae and some other material from the Lourinhã Formation.

He was associated with the Museu da Lourinhã, and after the excavations which lasted from the time of discovery until 1992,[2] the specimen was then moved into the museum, and catalogued under the number 414.

A year before being described as a new taxon, Dantas et al. assigned ML 414 to Lourinhasaurus alenquerensis, previously grouped under Apatosaurus.

José Bonaparte and Octávio Mateus studied the material of Lourinhasaurus, concluding one specimen, under the name ML 414, to be more closely related to diplodocids of the Morrison Formation, and thus warranting a new binomial name.

[2] David Weishampel et al. did not recognize all the material as belonging to Dinheirosaurus, and only found 9 dorsals in the holotype, while also misinterpreting the pubis as a limb fragment.

[4] Another pair of vertebrae, under collection number ML 418, was originally assigned to Dinheirosaurus by Bonaparte and Mateus, but is now considered to be a distinct new unnamed genus of diplodocid.

They are T-shaped in cross section, and display plesiomorphic features, although their incomplete state makes their identification uncertain.

[3] Other appendicular (non-vertebral) material includes a very incomplete and fragmentary shaft of the pubis, and over one hundred gastroliths.

63 cm (25 in) is the total measurement of the 14th cervical's centrum, which is well-preserved, complete, and concave along the bottom edge.

The neural spine, while compressed from above compared to the cervicals of Diplodocus, is massive, and projects upwards towards its posterior end.

In 2012 during a redescription of the taxon by Philip Mannion et al., it was recovered, in both cladograms, to be sister species to Supersaurus vivianae and together forming the most basal diplodocines.

A 2012 cladogram, published by Mannion et al. and using a modified matrix of Whitlock (2011) found that Dinheirosaurus was more primitive than Torneria and more derived than Apatosaurus.

[10] Amphicoelias altus Unnamed species Apatosaurus ajax Apatosaurus louisae Brontosaurus excelsus Brontosaurus yahnahpin Brontosaurus parvus Unnamed species Tornieria africana Supersaurus (=Dinheirosaurus) lourinhanensis Supersaurus vivianae Leinkupal laticauda Galeamopus hayi Diplodocus carnegii Diplodocus hallorum Kaatedocus siberi Barosaurus lentus Previously, Dinheirosaurus was classified within a Diplodocidae excluding Apatosaurus, for the differences anatomically are quite great.

If it did, it has been speculated that its tail could have been used like a bullwhip, with supersonic speed[11] or, more recently, as a tactile organ to keep in touch with other members of a group.

[4] Many theropods are known including an unnamed genus of abelisaurid;[15] the allosaurid Allosaurus europaeus; the ceratosaurid Ceratosaurus dentisculatus;[16] the coelurosaurians Aviatyrannis jurassica,[17] and cf.

[17] Sauropods are less common, with only an intermediate diplodocid as well as Dinheirosaurus;[3] the camarasaurid Lourinhasaurus alenquerensis; the turiasaur Zby atlanticus;[18] and the brachiosaurid Lusotitan known.

[19] Ornithischians are well represented, with identified remains persisting to Trimucrodon cuneatus;[20] Alocodon kuehnei;[21] the stegosaurians Dacentrurus armatus, Miragaia longicollum,[22] and Stegosaurus ungulatus;[23] the ankylosaurid Dracopelta zbyszewskii;[24] the ornithopods Draconyx loureiroi,[25] Camptosaurus sp.,[18] Phyllodon henkelli,[21] and cf.