My Brachiosaurus talk for Dinosaur Journey is now on YouTube
October 20, 2021
My Oct. 13 National Fossil Day public lecture, “Lost Giants of the Jurassic”, for the Museums of Western Colorado – Dinosaur Journey is now up on their YouTube channel. First 48 minutes are talk, last 36 minutes are Q&A with audience, moderated by Dr. Julia McHugh. New stuff from the 2021 field season — about which I’ll have more to say in the future — starts at about the 37-minute mark. Hit the 44-minute mark (and this and this) to find out what to do with all of the unwanted bird necks that will be floating around at the upcoming holidays.
Finally, big thanks to Brian Engh for finding our brachiosaur and for letting me use so much of his art, to John Foster, Kaelen Kay, Tom Howells, Jessie Atterholt, Thierra Nalley, and Colton Snyder for such a fun field season this year, and to Julia McHugh for giving me the opportunity to yap about one of my favorite dinosaurs!
Sauropod Vertebra Picture of the Week 
October 22, 2021 at 10:26 pm
Excellent talk.
If I understand correctly, the brachiosaurus was found below the changeover from mudstone to sandstone, while all the other large animals were found in the sandstone above the mudstone that contains the brachiosaurus?
how much (or how little) potential is there that there was substantial climate change across the mudstone to sandstone transition?
October 22, 2021 at 10:42 pm
Ah, that’s something I didn’t explain very well. There are several layers of sandstone, which are laterally continuous over pretty large areas–several km, at least–with mudstones and paleosols in between. We’re working on getting all of the stuff that we’ve found into a strat framework but we’re not there yet.
In any case, we think there probably was a substantial shift in the environment between the mudstone/paleosol layers and the sandstone layers, but whatever it was, it came and went several times in succession. At least four times.
If it sounds like I’m being deliberately vague, it’s not my intent, I just know less about strat than I do about anatomy. I’m trying not to speak beyond my limited understanding. There will be papers coming along on this site in the not-too-distant future, in which people who know a lot more geology than I do will explain what was going on.
You bring up a good point, though, which is that I was speaking as if it was all one fauna, in the sandstones (plural) and mudstones both. It might have been several different ones, through time or in different paleoenvironments, or both.
October 23, 2021 at 9:53 pm
Very enjoyable talk, thank you.
Pardon my noobness but I have a few questions I’d love to ask, to understand more.
– The brachiosaurus humeri you found – if both of these are here with the rib in this location, is there a good chance the rest of the skeleton could be present? If so, would it be easy to extract? Where on earth do you start, given the scale of what you’re looking for, and the scale of the location it could be in locally? Do you work along the strata?
– When you talk about what we know of brachiosaurus from the partial skeleton with pieces from several locations – how can you be sure they are indeed from the same species? How can a femur found in X be assumed to be the same species as a scapula found in Y? I assume this can only be confirmed when a complete skeleton is found – is this likely given the size of the beast?
– The giraffatitan specimen – you mention that the coracoid is fused in adult creatures; have we any idea of what the lifespan could have been of these animals, and at what stage we could expect to see growth plates closed and bones fused? Or would we need sequentially aged specimens to figure this out?
– The glue and camouflage tickled me, but then I wondered, how often does fossil theft occur? What do folks do with them, just put them up as trophies? How do you go about camouflaging them, and how easy is it to get the glue off afterwards?
– T rex poop – undigested chunks of muscle – this doesn’t sound like a particularly effective digestive system?
– Brachiosaur poop – you mentioned expecting to find pine needles and bark in it – what evidence do we have that indicates the diet brachiosaurs ate? Would it be the dental details correlating to what plant matter would have been available at the time? Or are there other clues? (Were sauropods browsers or grazers?)
Many thanks!
October 24, 2021 at 11:08 pm
Thank you for your answers, Matt.
I rather suspected the only answers available would be vague – so often that seems to be the case when asking about Jurassic ecosystems.
October 25, 2021 at 8:33 pm
Hello, P Ingledow, and thanks for the kind words. You should never apologize for being new to this stuff. We all were at one point. To answer your questions:
is there a good chance the rest of the skeleton could be present?
Yes, but only a chance. Sometimes paleontologists find complete, associated or even articulated skeletons, sometimes we just find a couple of bones. We really won’t know where on the spectrum this individual is until or unless we find any more bones.
If so, would it be easy to extract?
No, it would be a huge pain in the rear. But it would be worth it!
Do you work along the strata?
Yes, exactly. And we started that process this summer, but only cleared a few square feet. There is a lot of work left to do.
When you talk about what we know of brachiosaurus from the partial skeleton with pieces from several locations – how can you be sure they are indeed from the same species?
We can’t. We’re assuming there is only one brachiosaur species in the Morrison Formation until evidence of more than one is published.
How can a femur found in X be assumed to be the same species as a scapula found in Y?
As above — so far, all of the published brachiosaurid material from the Late Jurassic of North America is consistent with a single species, and that’s a simpler assumption than that there were multiple species. But there are lots of examples of similar assumptions turning out to be wrong. For a long time, all of the sauropod material from the Early Cretaceous of North America was referred to Astrodon/Pleurocoelus. As more and better material became available, we realized that there were actually many, many sauropod genera and species in the Early Cretaceous of North America.
I assume this can only be confirmed when a complete skeleton is found – is this likely given the size of the beast?
Your assumption is correct, and no, it’s not likely. In 121 years the most complete Brachiosaurus skeleton is still the type specimen, which is woefully incomplete.
Re: Giraffatitan growth and development, important work on this was done by Martin Sander and his lab, and published in several papers going back to 1999/2000. But growth plates tend to close fairly late in dinosaurs, and it’s not uncommon for big mounted skeletons to have unfused scapulocoracoids, and especially some unfused cervical ribs. Very little work has been done on correlating the timing of those fusions with growth and maturation information derived from bone histology.
The glue and camouflage tickled me, but then I wondered, how often does fossil theft occur?
Depends on location. Where we work in Utah, it’s a real concern. As I mentioned in the talk, the holotype specimen of Brontomerus was poached before the bits that we still have were collected — more info on that in this post.
What do folks do with them, just put them up as trophies?
The nice stuff ends up in corporate boardrooms or rich people’s living rooms, and the busted stuff gets sold off in rock shops. (Some, not all — many rock stops do not carry illegally-collected fossils.)
How do you go about camouflaging them, and how easy is it to get the glue off afterwards?
Camouflage: re-bury the bones — and yes, that is a pain, because we know we’re going to have to dig them back up later — and then make the site look naturalistic by smoothing out any footprints and tool marks, and then scattering rocks and sticks on the surface. The desert terrain is varied enough that it’s pretty easy to make a site look unidentifiable, especially after one or two rains.
Glue: I was keeping it simple because this was a public talk, but a better word than ‘glue’ would have been ‘consolidant’. It’s plastic dissolved in acetone, which we squirt all over the bone so it will sink it, the acetone will evaporate and leave behind the plastic, and the plastic will hold the bone together. The consolidant doesn’t come out, unless there is some reason to take it out later.
T rex poop – undigested chunks of muscle – this doesn’t sound like a particularly effective digestive system?
What is means is fast. Despite being a big animal, T. rex was pushing stuff through pretty quickly. More consistent with a fast metabolism than a slow one. Inefficient? Probably, but maybe it doesn’t matter if the next meal is coming along soon.
Brachiosaur poop – you mentioned expecting to find pine needles and bark in it – what evidence do we have that indicates the diet brachiosaurs ate?
Long necks and big, spoon-shaped teeth suggest that they ate up high, and fed on fairly tough stuff.
Would it be the dental details correlating to what plant matter would have been available at the time? Or are there other clues? (Were sauropods browsers or grazers?)
Woof, there are tons of papers on these issues, that get into all kinds of stuff, including neck posture and flexibility, jaw shape, mechanical advantage of the jaw muscles, tooth shape, tooth replacement rate, tooth microwear. I have a lot of opinions about that stuff, but the only area that I’m actually an expert on is the posture and flexibility of the neck. Probably the most relevant work by me and Mike on these issues are Taylor et al. (2009) and Taylor and Wedel (2013b), both of which are available at the links on the sidebar. Interestingly, the neck of Barosaurus may have been better adapted for sideways motion than up-and-down; for that see our preprints on the topic under the Taylor and Wedel (2016) link.
Sorry to just point you at papers on some of these things, rather than explaining them. I’m doing that only when the answers are complicated, and my time is too limited to unpack everything and do it all justice.