Dinheirosaurus

ML 414 was first uncovered in 1987 by Mr. Carlos Anunciação. He was associated with the Museu da Lourinhã, and after the excavations which lasted from the time of discovery until 1992, 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. ==Description==

Dinheirosaurus was an average sized diplodocid, and had an elongated neck and tail. The animal is not known well from non-vertebral material, currently only consisting of partial ribs and a fragment of a pelvis. One of the ribs attached to the cervicals, and is quite fragmentary. It is elongated, although that might be a feature of distortion. Also undescribed by Bonaparte & Mateus are a set of thoracic ribs. Two ribs are from the left side of the animal. They are T-shaped in cross section, and display plesiomorphic features, although their incomplete state makes their identification uncertain. Multiple right ribs are preserved, including both the shafts and heads. They are similar to the left ribs, which also show that they lack pneumatization. Other appendicular (non-vertebral) material includes a very incomplete and fragmentary shaft of the pubis, and over one hundred gastroliths. The pubis displays practically no anatomical features, and the gastroliths were not described in detail by Mannion et al. in 2012. Vertebrae The most distinguishing material of Dinheirosaurus comes from the vertebrae, which are well represented and described. Of the cervicals, only two of the assumed fifteen are preserved. According to Bonaparte & Mateus (1999), the cervicals would number 13 and 14. Apparently cervical 15 was lost during the excavation and removal of the holotype and only specimen of Dinheirosaurus. As of the original description, the thirteenth cervical was only prepared on the lateroventral portion. The length of the centrum is , and the fourteenth cervical is quite similar overall. 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. A relatively complete series of dorsal vertebrae are known, which number one to seven. All of the dorsals, however, are distorted upwards due to their state of preservation. Bonaparte & Mateus (1999) noted that the position of the dorsals was not certain, and that in fact the first dorsal could have been the last cervical or even the second dorsal. A similar numbering was found in Diplodocus, with the first and second dorsals similar in anatomy to the last and second-last cervical. The dorsal vary in length from the of the first dorsal to the of the seventh, eight and ninth dorsals. Height in the vertebrae is also quite variable, with the shortest height being tall to tall, increasing from the first dorsal. ==Classification==

Dinheirosaurus is not extremely well known, and as a consequence, its phylogenetic position is not certain. 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. However, a cladogram from 2014 found that their group was supported, but in fact more primitive than Apatosaurus, and therefore outside Diplodocinae. In 2015, Dinheirosaurus lourinhanensis was considered a species of Supersaurus in a new combination S. lourinhanensis; their results are shown below. }} Previously, Dinheirosaurus was classified within a Diplodocidae excluding Apatosaurus, for the differences anatomically are quite great. Bonaparte & Mateus found that a few features present suggested that Dinheirosaurus was more derived than Diplodocus, but plesiomorphic features also present conclude that they branched separately and Dinheirosaurus is not the descendant of Diplodocus. A 2004 study by Upchurch et al. found that Dinheirosaurus was an intermediate diplodocoid, along with Cetiosauriscus, Amphicoelias, and Losillasaurus. ==Paleobiology==

As a diplodocid, it is probable that Dinheirosaurus possessed a whip-tail. If it did, it has been speculated that its tail could have been used like a bullwhip, with supersonic speed or, more recently, as a tactile organ to keep in touch with other members of a group. Being related to both Apatosaurus and Diplodocus, Dinheirosaurus probably possessed a squared snout. This means that it was probably a non-selective ground-feeding sauropod. Digestion Dinheirosaurus is one of relatively few sauropods for which gastroliths were found obviously alongside the type specimen. In 2007, an experiment using Dinheirosaurus, Diplodocus (=Seismosaurus), and Cedarosaurus tested if sauropods used their gastroliths in an avian-style gastric mill. The analysis took into account that among the hundreds of sauropods found, gastroliths are only known from a few associated specimens. Authors chose to use the three sauropods with the most associated gastroliths, Dinheirosaurus, Diplodocus, and Cedarosaurus, because of the large amount of gastroliths found in birds. When birds were typically found to have 1.05% of their body weight gastroliths, the sauropod Diplodocus, which had the highest amount of gastroliths, only amassed to 0.03% body weight. This means that since the other sauropods Dinheirosaurus and Cedarosaurus had less gastroliths to body mass, an avian-style gastric mill is unlikely to have evolved in sauropods, and they instead might have used gastroliths to absorb minerals. ==Paleoecology==

Dinheirosaurus was one of many dinosaurs to have lived in the Lourinhã Formation during the Late Jurassic. the allosaurid Allosaurus fragilis; the ceratosaurid Ceratosaurus; the coelurosaurians Aviatyrannis jurassica, and cf. Richardoestesia; an intermediate theropod; and the brachiosaurid Lusotitan known. Ornithischians are well represented, with identified remains persisting to Trimucrodon cuneatus; Alocodon kuehnei; the stegosaurians Dacentrurus armatus, Miragaia longicollum, and Stegosaurus ungulatus; the ankylosaurid Dracopelta zbyszewskii; the ornithopods Draconyx loureiroi, Camptosaurus sp., Biogeography Many eusauropods, including Dinheirosaurus have been found in the Late Jurassic of Europe. The sauropods are from around the base of the Tithonian as based on the presence of Anchispirocyclina lusitanica. One sauropod, a diplodocid currently based on an unnamed specimen including vertebrae and some bones, is clearly different from Dinheirosaurus and Losillasaurus, confirming the presence of a least two and possibly more diplodocids in the Late Jurassic of Spain and Portugal. This is unique in the variety of diplodocoids in all Europe, with the only other genera possibly non-diplodocoid (Cetiosauriscus), or classified in Rebbachisauridae. This suggests that the biogeography of primitive sauropods is incomplete, with possible primitive eusauropods and diplodocids surviving in the Late Jurassic, potentially until the Berriasian. ==References==