Today, we bring you the long-overdue third installment in everyone’s  favourite Mystery Sauropod Dorsals serial, our trawl through the NHM’s collection of mostly isolated elements from the Wealden Supergroup.

Many of these elements are too bashed up to be diagnostic (with the Xenoposeidon holotype R2095 being an honourable exception).  But there are one or two that are much better preserved, and arguably the best of these are the pair of elements BMNH R88/R89, which in some sense belong to “Eucamerotus” (read on).  These are difficult to photograph well, because they are in a glass case in the public gallery, but fortunately Hulke (1880: plate IV) illustrated the more anterior and better preserved of the two:

Like far too many British sauropod specimens, this one is mired in a taxonomic hell-hole. It was described by Hulke as belonging to Ornithopsis, a genus based on a horribly non-diagnostic type specimen, and it is this name that appears on the exhibit label (along with the incorrect specimen numbers R89/90 … oh well, One Out Of Two Ain’t Bad.)

Here is my least bad photo of R88 and R89, in left lateral view, with R88 on the left:

Blows (1995) referred this pair of dorsals, and a bunch of other specimens, to another ancient British name, Eucamerotus — in fact, he nominated them as paratypes — but didn’t give any reason for doing so.  (He also referred to the R88/R89 pair jointly as R90, thus further muddling the specimen numbering.)  Blows’s reassignment to Eucamerotus is puzzling, because while the Eucamerotus type specimen is also pretty undiagnostic, consisting only of a partial neural arch, it does have one obvious apomophy, which is huge robust parapophyses supported on what I like the call The Prezygaparapophyseal Laminae Of Doom.  (Remind me to show you this specimen some time.)  That feature, of course, R88 and R89 completely lack.

So what are they?  I don’t think they can be referred with any confidence whatsoever to either Ornithopsis or Eucamerotus, two questionable genera of which at least the first is invalid.  So perhaps the right thing to do would be to torpedo those names and raise R88/89 as the type specimen of a new taxon?  There’s more work to do before taking such a step, not least an exhaustive trawl through the historical literature, but I think that might eventually prove the way to go.

Based on general proportions and overall “gestalt”, these vertebrae appear to be brachiosaurid — but I put them in a cladistic analysis a while back (so far unpublished) and they didn’t clade unambiguously with Brachiosaurus, so we’ll have to see how that develops when I finally get around to adding my thirty-odd new characters of the dorsals.  Don’t hold your breath.  At least, these elements are much more convincingly brachiosaurid than anything else I’ve seen from the Wealden.  So do they consitute Britain’s best brachiosaur?

Well, maybe.  Not if you count The Archbishop, Migeod’s Tendaguru brachiosaur, which I’ve been working on for waaay too long now, but really, really will describe Real Soon Now.  (Amazingly, this specimen has yet to appear on SV-POW!, unless you count my T-shirt in one of the photos of our Oxford Museum visit.)  But since this specimen is from the Tendaguru Formation of Tanzania, it should probably be discounted from the BBB competition.

In fact, Britain’s Best Brachiosaur is probably the “Barnes High Sauropod” from the Isle of Wight. But that’s in private hands and the ownership/availability situation is complex.  For that reason, no-one has yet published on it, and in fact I have never seen any of the material except what’s embedded in a wall-mount at Dinosaur Isle.  I’m not sure what’s happening with this specimen (I don’t think anyone is) but if I ever get a chance to find out, I will!

References

• Blows, William T.  1995.  The Early Cretaceous brachiosaurid
  dinosaurs Ornithopsis and Eucamerotus from the Isle of
  Wight, England.  Palaeontology 38 (1): 187-197.
• Hulke, J. W.  1880.  Supplementary Note on the Vertebræ of Ornithopsis, Seeley, = Eucamerotous, Hulke.  Quarterly Journal of the Geological Society 36: 31-35.  doi:10.1144/GSL.JGS.1880.036.01-04.06