page_title: Leonerasaurus
section_title: Vertebrae
hierarchical_section_title: Leonerasaurus / Description / Vertebrae
caption_attribution_description: Cervical vertebrae 3–5 of Leonerasaurus taquetrensis (MPEF-PV 1663). A–B, lateral view. C–D, dorsal views. Scale bars represent 10 mm. Hatched pattern represents broken surfaces and dotted pattern represents sediment. Abbreviations: c3-c5, cervical vertebrae 3 through 5; di, diapophysis; pa, parapophysis; pri, prezygapophyseal ridge; epi, epipophysis; psf, postspinal fossa; sk, sagittal keel.
context_page_description: Leonerasaurus is a basal genus of sauropodomorph dinosaur. Currently, there is only one species known, named L. taquetrensis by Diego Pol, Alberto Garrido and Ignacio A. Cerda in 2011. The fossil, an incomplete subadult individual, was found in the Las Leoneras Formation in Argentina. This formation is probably Early Jurassic in age. Leonerasaurus was a small non-sauropod sauropodomorph, showing an unusual combination of basal and derived characters. This indicates that the evolution of early sauropodomorphs witnessed a great degree of convergent evolution.
context_section_description: The neck of Leonorasaurus is known almost completely, only the atlas is lost. The nine remaining cervicals were found articulated with the first five complete dorsal (trunk) vertebrae. Additionally, a probable sixth dorsal and an articulated group of three mid-dorsals were found. Fragments of more posterior dorsals and of ribs were also recovered. The sacrum (fused vertebrae that form the core of the hip), consisting of four vertebrae, is nearly complete, but no bones of the tail was recovered.
  The overall shape of the neck vertebrae is typical for basal sauropodomorphs, but Pol et al. interpret the remains of the neural arches to indicate a more sauropod-like shape. Some characters, however, show an intermediate development. In the trunk, the vertebrae show typical non-sauropod characters, such as relatively long and low neural arches with a narrow anterior ridge (the anteriormost dorsal vertebrae have slightly high neural arches), an anteriorly placed parapophysis (one of the articulation points for the ribs), and lack of or less strong development of certain laminae (thin ridges). The diapophysis (the second articulation for the rib) is also in the same position as in basal sauropodomorphs. A lamina connecting the diapophysis to the prezygapophysis on all dorsals, but not in no-sauropod sauropodomorphs, is present in the posterior dorsals.
caption: Cervical vertebrae
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