November 25, 2016
So I came across this tweet from Laurent Gatto, who’s head of the Computational Proteomics Unit at the University of Cambridge, UK:
My immediate reaction was not to retweet. Why? Because I am not comfortable recommending rejection (or acceptance!) of something I’ve not seen. I said so, and Laurent explained the real issue:
So I have two simple questions:
First, How can this massive spending on public money possibly be confidential? What justification can there possibly be for that? And second, how can there be meaningful discussion of the offer on the table if no-one knows what it is?
And then I remembered the classic explanation of confidentiality clauses from Elsevier’s David Tempest: “we have this level of confidentiality […] Otherwise everybody would drive down, drive down, drive drive drive”.
So my first reaction was to say that if anyone comes across a leaked copy of the draft agreement, let me know and I will link to it from this post. But I am also open to hear from anyone who thinks there is a legitimate reason, that I’ve not thought of, to enforce confidentiality. So if you have a reason, please mention it in the comments. If not, but you know where there is a leaked copy, email me privately on email@example.com.
November 21, 2016
The question of whether sauropod cervicals got longer through ontogeny came up in the comment thread on Mike’s “How horrifying was the neck of Barosaurus?” post, and rather than bury this as a comment, I’m promoting it to a post of its own.
The short answer is, yeah, in most sauropods, and maybe all, the cervical vertebrae did lengthen over ontogeny. This is obvious from looking at the vertebrae of very young (dog-sized) sauropods and comparing them to those of adults. If you want it quantified for two well-known taxa, fortunately that work was published 16 years ago – I ran the numbers for Apatosaurus and Camarasaurus to see if it was plausible for Sauroposeidon to be synonymous with Pleurocoelus, which was a real concern back in the late ’90s (the answer is a resounding ‘no’). From Wedel et al. (2000b: pp. 368-369):
Despite the inadequacies of the type material of Pleurocoelus, and the uncertainties involved with referred material, the genus can be distinguished from Brachiosaurus and Sauroposeidon, even considering ontogenetic variation. The cervical vertebrae of Pleurocoelus are uniformly short, with a maximum EI of only 2.4 in all of the Arundel material (Table 4). For a juvenile cervical of these proportions to develop into an elongate cervical comparable to those of Sauroposeidon, the length of the centrum would have to increase by more than 100% relative to its diameter. Comparisons to taxa whose ontogenetic development can be estimated suggest much more modest increases in length.
Carpenter & McIntosh (1994) described cervical vertebrae from juvenile individuals of Apatosaurus and Camarasaurus. Measurements and proportions of cervical vertebrae from adults and juveniles of each genus are given in Table 4. The vertebrae from juvenile specimens of Apatosaurus have an average EI 2.0. Vertebrae from adult specimens of Apatosaurus excelsus and A. louisae show an average EI of 2.7, with an upper limit of 3.3. If the juvenile vertebrae are typical for Apatosaurus, they suggest that Apatosaurus vertebrae lengthened by 35 to 65% relative to centrum diameter in the course of development.
The vertebrae from juvenile specimens of Camarasaurus have an average EI of 1.8 and a maximum of 2.3. The relatively long-necked Camarasaurus lewisi is represented by a single skeleton, whereas the shorter-necked C. grandis, C. lentus, and C. supremus are each represented by several specimens (McIntosh, Miller, et al. 1996), and it is likely that the juvenile individuals of Camarasaurus belong to one of the latter species. In AMNH 5761, referred to C. supremus, the average EI of the cervical vertebrae is 2.4, with a maximum of 3.5. These ratios represent an increase in length relative to diameter of 30 to 50% over the juvenile Camarasaurus.
If the ontogenetic changes in EI observed in Apatosaurus and Camarasaurus are typical for sauropods, then it is very unlikely that Pleurocoelus could have achieved the distinctive vertebral proportions of either Brachiosaurus or Sauroposeidon.
A few things about this:
- From what I’ve seen, the elongation of the individual vertebrae over ontogeny seems to be complete by the time sauropods are 1/2 to 2/3 of adult size. I get this from looking at mid-sized subadults like CM 555 and the hordes of similar individuals at BYU, the Museum of Western Colorado, and other places. So to get to the question posed in the comment thread on Mike’s giant Baro post – from what I’ve seen (anecdata), a giant, Supersaurus-class Barosaurus would not necessarily have a proportionally longer neck than AMNH 6341. It might have a proportionally longer neck, I just haven’t seen anything yet that strongly suggests that. More work needed.
- Juvenile sauropod cervicals are not only shorter than those of adults, they also have less complex pneumatic morphology. That was the point of the figure at the top of the post. But that very simple generalization is about all we know so far – this is an area that could use a LOT more work.
- I’ve complained before about papers mostly being remember for one thing, even if they say many things. This is the canonical example – no-one ever seems to remember the vertebrae-elongating-over-ontogeny stuff from Wedel et al. (2000b). Maybe that’s an argument for breaking up long, kitchen-sink papers into two or more separate publications?
November 18, 2016
Oh man, 2016, you are really working on my nerves.
Sometimes it’s a positive balm to hold a piece of an animal dead and gone for 145 million years, or stare at a thousand vertical feet of sandstone, and know that we are all ants.
These lovelies here intrigue me deeply. They’re the three caudal vertebrae recovered from the Snowmass Haplocanthosaurus that John Foster and I described a couple of years ago. Pretty sure I’ll have more to say about them in the future. For now it’s enough that they’ve come across such a vast gulf of time and given this stressed-out primate a little perspective.
Foster, J.R., and Wedel, M.J. 2014. Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison Formation (Upper Jurassic) near Snowmass, Colorado. Volumina Jurassica 12(2): 197–210. DOI: 10.5604/17313708 .1130144
November 2, 2016
I’ve been writing for Sky & Telescope, the American astronomy magazine, for a year now. My first feature article was published last December (details here), my second came out this April (ditto), and my latest is in the current (December 2016) issue, which should be hitting newsstands this week. I’ve also been writing the “Binocular Highlight” column since June.
My latest feature article, “Twelve Steps to Infinity”, is my favorite thing I’ve ever written about astronomy, and maybe my favorite thing I’ve ever written, period.* I’m posting about it here because the concept should be interesting to all students of the past: the speed of light is finite, so when we look out into space, we are also looking back in time. We see the moon as it was 1.28 seconds ago, the sun as it was 8.3 minutes ago, Jupiter anywhere from 33 minutes to over an hour ago, depending on whether we’re on the same side of the sun or not, and Neptune after four hours – at that distance, our 16-light-minute swing around the sun hardly makes a difference. Most of the stars visible to the naked eye are within 2000 light years, which is 2% or less of the diameter of our Milky Way galaxy. With binoculars or a small telescope you can track down numerous external galaxies and see them as they appeared tens of millions of years ago. One of my favorite observations is seeing the light of the quasar 3C 273, which started traveling 2.4 billion years ago, when our single-celled ancestors were gearing up for the Great Oxygenation Event. (If you’d like to replicate that feat yourself, you can get a very capable, “lifetime” telescope for a little over a hundred bucks. I recommend the Orion SkyScanner 100 – see this and this for more information.)
My new Sky & Tel article doesn’t go nearly that far back – in fact, I don’t even make it out of the Cenozoic. But the concept scales all the way out, so if a particular event in Phanerozoic history is near to your heart, there is probably a star, nebula, cluster, or galaxy whose light left at the right time, which you could observe with binoculars or a small telescope (although the distribution is gappy between half a million and 30 million light years, where there just aren’t that many nearby galaxies). The Messier and Caldwell catalogs are good places to start, and there are hordes of online resources (many funded by your tax dollars by way of NASA) you can use to find a match. If I get really motivated I might post a table of easily-observed celestial objects and their lookback times. In the meantime, if you have a date in mind, leave it in a comment and I’ll find something temporally close for you to go look at.
Lots of people provided assistance and inspiration. Steve Sittig, who runs the Hefner Observatory at the Webb Schools here in Claremont, helped me refine the idea through numerous conversations, and did a trial observing run with me last autumn. Fellow paleontologists Alan Shabel and Thierra Nalley guided me on hominid history (needless to say, any remaining errors are mine). My editor at Sky & Telescope, S.N. Johnson-Roehr, made numerous small improvements, and the S&T art department made the article even more beautiful than I had hoped. Finally, the little plesiadapiforms at the end of the piece are there thanks to Pat Holroyd, who introduced me to them when I was at Berkeley. Many thanks, folks!