Matt bought an Iguanodon pelvis … OR DID HE???!
September 16, 2019
We’re just back from an excellent SVPCA on the Isle of Wight. We’ll write more about it, but this time I just want to draw attention to a neat find. During a bit of down time, Matt and Vicki were wandering around West Cowes (the town where the scientific sessions were held), when they stumbled across a place called That Shop. Intrigued by all the Lego figures in the window, they went in, and Matt found a small section of fossils. Including … an Iguanodon pelvis, supposedly certified as such by the Dinosaur Isle museum.
Here it is: I imagine that whoever classified it read this elongate concave surface as part of the acetabulum. Matt’s hypothesis is that they mistook it for a sacral vertebra and that became “pelvis” via over-simplification.
It’s about 18 cm in a straight line across the widest part, or 20 cm around the curve.
Here is an actual documentary record of Matt’s moment of discovery:
Yep, you got it! It’s a sauropod vertebra! (Matt would never have spent good money on a stinkin’ appendicular element of a stinkin’ ornithopod.)
Specifically, it’s the bottom half of the front part of the centrum of a dorsal vertebra:
“Eucamerotus” dorsal vertebra NHMUK PV R88 in right lateral and anterior views. Non-faded portions show the location of the Wedel Specimen. Modified from Hulke (1880: plate IV).
In these photos, we’re looking down into it more or less directly dorsal view, with anterior to the left. Click through the photos, and — once you know what you’re looking at — you can clearly see the pneumatic spaces: nice patches of finished bone lining the camellae, with trabecular bone in between.
Clearly there’s nowhere near enough of this to say what it is with any certainty. But our best guess is that it seems compatible with a titanosauriform identity, quite possibly in same space as the various Wealden sauropod dorsals that have been assigned to Ornithopsis or Eucamerotus.
References
- 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
The bizarre caudal neural spines of Tambatitanis amicitiae
August 13, 2014
Today for the first time I saw Saegusa and Ikeda’s (2014) new monograph describing the Japanese titanosauriform Tambatitanis amicitiae. I’ve not yet had a chance to read the paper — well, it’s 65 pages long — but it certainly looks like they’ve done a nice, comprehensive job on a convincing new taxon represented by good material: teeth, braincase, dentary, atlas, and as-yet unprepared fragmentary cervical, fragmentary dorsals, sacral spines, some nice caudals, some ribs and chevrons, and pubis and ilium.
What catches the eye immediately is the bizarre forward-curved neural spines of the anterior caudals:
Saegusa and Ikeda (2104: fig. 8): Tambatitanis amicitiae gen. et sp. nov., holotype (MNHAH D-1029280). A, Cd2–Cd11 in right lateral view. B, Cdx1–Cdx2 in right lateral view.
Here’s the third caudal in detail. (The first is fragmentary, and the second has some minor reconstruction near the tip of the spine which sceptical readers might think is covering up a misconstruction):
Saegusa and Ikeda (2014: fig. 11): Tambatitanis amicitiae gen. et sp. nov., holotype (MNHAH D-1029280). A–F, stereopairs of Cd3. A, right lateral view. B, left lateral view of the neural spine. C, anterior view. D, posterior view. E, dorsal view. F, ventral view. G, CT slices through the neural spine of Cd3, part corresponding to the matrix that filling the internal chamber is removed from the image. Greek letters in B and D indicate the position of CT slices shown in G. Scale bar = 10cm.
And here is the right-lateral view in close-up:
Saegusa and Ikeda (2014: fig. 11): Tambatitanis amicitiae gen. et sp. nov., holotype (MNHAH D-1029280) in right lateral view.
A phylogenetic analysis based on that of D’Emic (2012) recovers the new taxon in a polytomy with the Euhelopus clade that’s going to need a new name pretty soon, since it keeps growing and can’t be called Euhelopodidae for historical reasons: [that should probably be called Euhelopodidae: see discussion in comments]:
Saegusa and Ikeda (2014: fig. 23): Phylogenetic relationships of the titanosauriform sauropod Tambatitanis amicitiae gen. et sp. nov. from the Lower Cretaceous Sasayama Group of Tamba, Hyogo, Japan produced using the matrix of D’Emic (2012) with the addition of Tambatitanis. The final matrix, including 29 taxa and 119 characters, was analyzed in PAUP* 4.0b10. Left side, strict consensus of 81 most parsimonious trees (length = 207; CI = 0.609; RI = 0.8010; RC = 0.489), figures below nodes are decay indices. Right side, 50% majority rule consensus, figures above and below nodes represents the percentage of MPTs in which the node was recovered (only those relationships recovered in over 50% of the MPTs are shown).
Nice to see that new sauropods just keep on rolling out of the ground faster than we can blog about them!
References
- D’Emic, Michael D. 2012. The early evolution of titanosauriform sauropod dinosaurs. Zoological Journal of the Linnean Society 166:624-671.
- Saegusa, Haruo, and Tadahiro Ikeda. 2014. A new titanosauriform sauropod (Dinosauria: Saurischia) from the Lower Cretaceous of Hyogo, Japan. Zootaxa 3848(1):1-66. doi:10.11646/zootaxa.3848.1.1
Sauropod Vertebra Picture of the Week 
