Here is another beautiful but (so far) unidentifiable isolated dorsal vertebra from the Wealden Supergroup. Rather than the usual orthogonal views (anterior, posterior, lateral) this is in an oblique view: right anterolateral. This vertebra is one of two that, together, make up the specimen BMNH R90. For my own convenience I have assigned them lower-case latters so each can be referred to individually. I call this one R90a.
It’s very rare that all three of us SV-POW!ers get together: in fact, until Tuesday this week, it had only ever happened once, at SVPCA 2005. But as Matt was spending nearly a fortnight with me (Mike) in England, far from his native land — an unholy blend of Oklahoma and California — it would have been stupid not to have all got together.
At the risk of turning this blog into <em> Brachiosaurus brancai </em> 8th Cervical Picture of the Day, here’s a quick tutorial on your basic sauropod vertebral anatomy, using everyone’s favourite cervical vertebra. This picture shows the same vertebra as was photographed in the very first SV-POW! entry.
Abs T r Ac T It has recently been argued that neural spine bifurcation increases through ontogeny in several Morrison Formation sauropods, that recognition of ontogenetic transformation in this ‘key character’ will have sweeping implications for sauropod phylogeny, and that Suuwassea and Haplocanthosaurus in particular are likely to be juveniles of known diplodocids. However, we find that serial variation in sauropod vertebrae can mimic ontogenetic change and is therefore a powerful confounding factor, especially when dealing with isolated elements whose serial position cannot be determined. When serial position is taken into account, there is no evidence that neural spine bifurcation increased over ontogeny in Morrison Formation diplodocids. Through phylogenetic analysis we show that neural spine bifurcation is not a key character in sauropod phylogeny and that Suuwassea and Haplocanthosaurus are almost certainly not juveniles of known diplodocids. Skeletochronology based on the sequence of skeletal fusions during ontogeny can provide relative ontogenetic ages for some sauropods. Although such data are sparsely available to date and often inconsistent among sauropod genera they provide another line of evidence for testing hypotheses of ontogenetic synonymy. Data from skeletal fusions suggest that Suuwassea and Haplocanthosaurus are both valid taxa and that neither is an ontogenetic morph of a known diplodocid.
Just a quick post to link to all six (so far) installments of the “necks lie” series. I need this because I want to cite all the “necks lie” posts in a paper that I’ll shortly submit, and it seems better to cite a single page than four of them.
A while back, Matt speculated on the size of the allegedly giant mamenchisaurid <em> Hudiesaurus </em> . At the time, all he had to go on was Glut’s (2000) reproduction of half of Dong (1997:fig. 3), and a scalebar whose length was given incorrectly. The comments on that article gave some more measurements, but we never got around to showing you the figures of the vertebra in question, so here it is: Hudiesaurus sinojapanorum IVPP V.
Well, not <em> really </em> really. Appendicular skeleton of savannah monitor lizard Varanus exanthematicus, "Charlie", in dorsal view. What we have here is of course the bones of all four feet of a lizard (plus the limb bones): “sauropod” means “lizard foot”, so lizard-foot skeletons are sauropod skeletons — right? (Note that the hind limbs are arranged in a weird posture here, with the knees bent forward.
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