Dinosaur "mummies," specimens that have undergone unusual preservation and retain some skin impressions along with the bones, are always exciting when announced, one of the most famous being the "teenage" Brachylophosaurus dubbed "Leonardo." (See here for information from Kodak on Leonardo, as well as this page from the Judith River Dinosaur Institute) This particular specimen, perhaps the most well-preserved dinosaur ever discovered, has been known for quite some time, but few details have emerged about the preserved soft anatomy impressions. A paper by Murphy et al., "'Leonardo,' a mummified Brachylophosaurus (Ornithischia: Hadrosauridae) from the Judith River
Formation of Montana," was collected in the symposium book Horns and Beaks about ornithischian dinosaurs, and although I haven't read this paper there is still a lot to be discussed in terms of Leonardo's anatomy from what I can gather from those who have read it. Another mummy dinosaur named "Dakota", however, may soon scoop "Leonardo" when it comes to some details about hadrosaur mummies.
When I first saw the news stories about forthcoming scientific data about a mummy dinosaur, I thought "Oh, so they've finally gotten around to releasing more information about Leonardo!" It turns out I was wrong. While Leonardo is still having his own 1-hour Discovery Channel documentary (click here to see a trailer) and will likely keep us waiting as such a find could take a lifetime of study, paleontologist Phillip Manning of Manchester University in England will soon release a new book Grave Secrets of Dinosaurs: Soft Tissues and Hard Science (a review of which will be presented here as soon as I receive my copy), with a children's book DinoMummy: The Life, Death, and Discovery of Dakota, a Dinosaur From Hell Creek out today and a forthcoming National Geographic special, Dino Autopsy, all about a mummy hadrosaur named "Dakota."(Manning will also be giving a lecture about "Dakota" at the AMNH on January 29th, 2008. I'll be there.) All this fanfare is exciting, but the most frustrating part of it is that I have no idea when we'll get a look at the science behind some of the news announcements. A LiveScience article, "Mummified Dinosaur May Have Outrun T. rex" is crawling with hypotheses about running speed, weight, and even color of the hadrosaurine dinosaur, but as Matthew Carrano of the Smithsonian is noted as saying in the article, I can't comment on any of this yet because I haven't seen the data, although the specimen is certainly a significant one.
National Geographic has released a number of images and a video (which I assume is a preview of the full documentary) today, though, although we still don't even know what the genus and species of "Dakota" is yet. I suppose I'll have to wait, but in the meantime I have to wonder what it is about hadrosaurs that make them seemingly ideal for such preservation. The AMNH has the mummy Edmontosaurus collected by the Sternbergs and the exquisitely preserved Corythosaurus collected by Barnum Brown, "Leonardo" and "Dakota" being hadrosaurs, as well (I know there are others, but I am not familiar with them). Skin impressions are known for an even wider variety of dinosaurs, but it is the hadrosaurs that seem to have a bias, however rare, towards this type of preservation. I'm not well versed enough in taphonomy or in the paleoecology of the sites in which the known "mummies" have been found so I can't even hazard a guess at this point, but it is interesting to see how different dinosaur taxa all have their own taphonomic quirks. Perhaps it's merely a matter of hadrosaurs being so abundant in coastal floodplain type settings that such preservation is bound to happen sooner or later, and perhaps there are "mummies" of other kinds of dinosaurs out there that we haven't found yet. Skin impressions are probably more abundant than once thought, now that paleontologists have a better idea of what to look for than did the fossil hunters of ages ago, but I still must admit that I am curious as to the taphonomic factors that produced hadrosaur mummies, even if there ends up being no significant difference other than the sheer number of organisms present in a given environment.
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Good point--duckbills seem to have a preservation bias (HA!) and I wonder what environments they frequented that allowed such great fossilization.
Having worked the Alberta fossil zones I can tell you a big part of why Hadrosaurs the ones you find with this kind of perservation.
You find 20 hadrosaurs before you find anything else! Regradless of perservation type (minus bonebeds in Dinosaur Park... those for some reason are all Ceratopsian... though read some of David Eberth's papers on this to see the neat insights we're currently getting about hte park). The entire western interior seaway terrestial environment as we know it today is represented by almost nothing but coastal flood plain environments. These have a real perservational biasis towards large complete specimens
In other words they were the most common large animals of the time, and thus if something was going to win the "lottery" of the extremely rare conditions lining up for this kind of perfect perservation they were the most likely to be it. Simply for more of them being around for the right place and timing.
To say that we don't find other dinosaurs as well perserved as Brown's Corythosaur isn't true. There were several animals found by Brown and the Sternberg with skin impressions, granted most were duckbills (though I believe one of the Centrosaurs or other certatopsians yielded skin as well). None of them mummies (Alberta was too wet for this as the time). It turns out a lot of Dinosaur Provincal Park's dinos have these impresions if you prep them carefully (which the Tyrrell is starting to try and do). Meaning that we've probably lost several great examples of these due to gunwhoe preping.
There is every likely hood that somewhere out there in the ground there are the remains of some nice mummified coelurosaurids, ceratopsians, ankylosaurids, and pachyceplosaurids. They were just more rare in their time than hadrosaurs thus there'd be less to be perfectly mummified, and then conversely less to be eroded out for us to find (some of these have sadly already eroded).
Traumador; Thanks for your first-hand insight. I figured that the sheer abundance of hadrosaurs and the presence of environments conducive to quick burial would be important, but I'm just curious as to why other dinosaurs that have left skin impressions have not been found as generally complete "mummies." I did not say that no skin impressions or good preservations have been found, but I did draw a difference between a dinosaur on which some skin had been found and these "mummies" that are very much complete with large patches of skin present on articulated skeletons.
You bring up a good point about "knowing what we're looking for," though, and some soft organ impressions being lost due to preparation and removal of remains from a site. Perhaps hadrosaurs just won the statistical lottery of having complete, articulated skeletons end up with exceptional preservation, but I still have to wonder if there is something else at play in terms of taphonomy.
Oh sorry didn't mean for my skin impression bit to sound so harsh *embrassed face*
There might be a slight chance it's taphonomy, but at the same time there are only 3 such specimens compared to how many normal skeletons found. I'd personally say it's just special conditions perserving them not hadrosaur decomposition
I eagerly keep my fingers crossed for the chance that one day, we'll find a complete mummified Argentinosaurus or any of the other giant sauropods. Now that would be a real nightmare to remove and prep. =)
Pete Larson and co. had a poster at SVP called "skinning a Triceratops" which presented a well-preserved Triceratops from the Zerbst Ranch near the site where Sternberg got his "mummy." The Triceratops had extensive skin preservation including lots of little knobs that the authors suggested migh be bristle-bearing "follicles"....