Palaeontology News

[Lt. Killer M]

Here, I'll post interesting palaeontology news, and anything from related fields that is of interest to me. Articles, press releases, short comments on my visits to collections and digs and so on.

The first post will be used or the articles, while the second one is reserved for my comments.

Feel free to debate, but please DO REFRAIN from posting creationist moronities, directly or in disguise! If you are UNSURE, ask! If you wish for more information - ASK! but do not post 'radiocarbon dating is wrong, Allah is great' and run. I can run faster than you (figuratively spoken) .



1) Fossilized dinosaur skin traces found for first time in Japan

http://mdn.mainichi-msn.co.jp/nation...na008000c.html


KATSUYAMA, Fukui -- Fossilized dinosaur skin traces have been found in a 120-million-year-old rock bed here -- the first of its kind to be discovered in Japan, the prefectural board of education said Thursday.

The fossilized skin traces, which show round and polygonal scales measuring between 3 and 5 millimeters in diameter, was found in the Kitatanicho district of Katsuyama, and dates back to the Lower Cretaceous period, putting its age at around 120 million years old.

Fukui Prefectural Dinosaur Museum Deputy Director Yoichi Azuma hailed the discovery.

"We've had to rely on overseas data for reproducing dinosaur skin, but now domestic data is available. There is a possibility that clearer fossils of dinosaur skin traces will be found in the same area," said 57-year-old Azuma, who holds a doctorate in paleontology.

Experts believe the skin comes from the leg of a herbivorous dinosaur, judging by the shape, but say it's difficult to identify its species without any fossilized skeletal remains.

Fossilized bones, teeth and claws from both herbivorous and carnivorous dinosaurs have previously been found in the area, and experts have successfully reproduced the entire skeleton of a dinosaur using fossils excavated in the area. (Mainichi)




2) How to look at dino tracks

I am happy to present an excellent papper by a friend of mine, Jesper Milan:

Milan, J. and Loope, D.B. (2007): Preservation and Erosion of Theropod Tracks in Eolian Deposits: Examples from the Middle Jurassic Entrada Sandstone, Utah, U.S.A.. J. Geology 115: 375-386.


http://www.eurekalert.org/pub_releas...-htl043007.php

A new study appearing in the May issue of The Journal of Geology provides fascinating insight into the factors geologists must account for when examining dinosaur tracks. The authors studied a range of larger tracks from the family of dinosaurs that includes the T. Rex and the tridactyl, and provide a guide for interpreting the effects of many different types of erosion on these invaluable impressions.

“Well-preserved vertebrate tracks in the rock record can be an invaluable source of information about foot morphology, soft tissue distribution, and skin texture,” write Jesper Milàn (Geological Institute, University of Copenhagen) and David B. Loope (Department of Geosciences, University of Nebraska, Lincoln). “However, in most instances, the tracks are less than perfectly preserved, and sometimes they can be barely recognizable as tracks at all.”

With this in mind, Milàn and Loope sought to describe and categorize different levels of preservation. For example, dinosaur tracks may still exist as true tracks, that is, the original prints left in the ground by the dinosaur. True tracks preserve many of the anatomical details of the foot, such as number of digits and impressions of claws.

However, the true tracks may be filled with sediment or the original tracked surface may have eroded away. In the latter case, erosion may expose prominent layers of concentric circles extending from the former location of the true track. These “undertracks” reveal the squishing and displacement of sand when the heavy dinosaur took a step.

“The tracks and undertracks of large theropods found in the [Middle Jurassic] Entrada Sandstone at the studied locality come in a wide range of morphologies, mainly as a result of present-day erosion that has exposed the track-bearing surfaces at different depths,” the researchers explain. “[They] demonstrate that great care should be taken when describing fossil footprints that have been exposed to subaerial erosion, because the shape, dimensions, and general appearance of the footprint become seriously altered by erosion.”

Geologists also must account for whether the step was taken on a sloped surface or on a horizontal surface, and whether it was taken during dry season or wet season.

For example, estimating foot length from tracks can be inaccurate without these considerations – the more erosion that has occurred, the larger the apparent dimensions of the track. Applications of this apparently larger foot size derived from an undertrack may lead to calculations of higher estimated hip length, and, as the authors point out, may also lead to slower speed estimates.



this pic shows how one and the same animal can make apparently different tracks!


And another one from a friend of mine (of sorts); I have heard his talks about it about five different times and still don't really get what he's on about - must be his British accent

3) Cope's Rule in the Pterosauria, and differing perceptions of Cope's Rule at different taxonomic levels

Hone, D.W.E. and BENTON, M.J. (2007): Cope's Rule in the Pterosauria, and differing perceptions of Cope's Rule at different taxonomic levels. Journal of Evolutionary Biology 20: 1164–1170.

The remarkable extinct flying reptiles, the pterosaurs, show increasing body size over 100 million years of the Late Jurassic and Cretaceous, and this seems to be a rare example of a driven trend to large size (Cope's Rule). The size increases continue throughout the long time span, and small forms disappear as larger pterosaurs evolve. Mean wingspan increases through time. Examining for Cope's Rule at a variety of taxonomic levels reveals varying trends within the Pterosauria as a whole, as pterodactyloid pterosaurs increase in size at all levels of examination, but rhamphorhynchoid pterosaurs show both size increase and size decrease in different analyses. These results suggest that analyses testing for Cope's Rule at a single taxonomic level may give misleading results.

[Lt. Killer M]

Comments:


1) interestingly, this find is NOT associated with bones. Also, judging from the pic, it may be that this is a part of a mummy - always interesting!


2) A great paper, and great work! I remember well the course in ichnology I took with the legendary Prof. Seilacher of Tübingen and Yale universities. He also warned us about the dangers of undertracks and overtracks. Well, I do not trust ichnology too much anyways.

[socralynnek]

Allah dating is wrong, radiocarbon is great!

Is that better, eh?




Ahem, I am curious on whether they haven't found such thing yet because they simply overlooked it or whether those are very very very rare.

[Lt. Killer M]

quote:Originally posted by socralynnek

Allah dating is wrong, radiocarbon is great!

Is that better, eh?

MUCH!

quote:
Ahem, I am curious on whether they haven't found such thing yet because they simply overlooked it or whether those are very very very rare.

Both, in my experience. For one thing, certain sediments simply have hardly a chance - so if you dig primarily in that kind of stuff, you will find little skin. But some of these sediments have other advantages, which make them choke full of fossils, so much digging is done in them - e.g. Morrisson Formation.

On the other hand, some places are choke full of skin - but only itzy bitzy pieces.

And, often, skin was simply overlooked. Especially if preparation is easy, it was simply scraped off before it was recognized.

[grahamiam]

Nice find. 130 million years for scales on the skin, what is the nearest date for feathers? With the recent find in the T-Rex DNA WRT chicken DNA, I'm kinda intreged by the possibility of very large, feathered Dinosaurs (as silly as this sounds, I'm not joking).

[digger760]

you mean like teradactyles, or is that something that Fred Flinstone just invented

[Beorn]

Pterodactyle is an actual dinosaur (pronounced just about tera), like the flying one with a long beak that rings Fred Flintstone's work bell IIRC.

[Lt. Killer M]

quote:Originally posted by Beorn

Pterodactyle is an actual dinosaur (pronounced just about tera), like the flying one with a long beak that rings Fred Flintstone's work bell IIRC.

sorry to disappoint you, but pterodactyles (Pterodactylus and consorts) are pterosaurs, the archosaur lineage that Hone's latest paper deals with, a kind of 'cousin' group to dinosaurs. They are not - repeat: NOT - dinosaurs!

[Beorn]

They do star in the Flintstones and they did exist though, which was my point

[Lt. Killer M]

quote:Originally posted by Beorn


They do star in the Flintstones and they did exist though, which was my point

indeed - and some people really go nuts over them (I mean nuts: 'Dino' Frey of the Karlsruhe museum has gone nuts, and he works on pterosaurs exclusively).