Showing posts with label Shakespeare. Show all posts
Showing posts with label Shakespeare. Show all posts
Tuesday, 27 May 2014
A poorly preserved ornithopod track
Here is another example of a "questionable" dinosaur track from Pula. According to my scale I would grade it as a poorly preserved track (***). It is not easy to spot on these weathered rocks, although it is a convex, or relief track. The natural cast. It is slightly darker colour and there are more similar prints there. In its overall shape it does remind of an ornithopod, iguanodontoid footprint of the Hadrosauropodus type, but due to the state of its preservation it may still be a theropod.
See the b/w outline of Hadrosauropodus langstoni - Lockley et al. (2003) track at the bottom.
My interpretation is the red outline over the print in the second image.
Some of the Cretaceous hadrosaur tracks are well described in a paper. HADROSAUR FOOTPRINTS FROM THE UPPER CRETACEOUS FRUITLAND FORMATION, SAN JUAN BASIN, NEW MEXICO, AND THE ICHNOTAXONOMY OF LARGE ORNITHOPOD FOOTPRINTS SPENCER G. LUCAS1, ROBERT M. SULLIVAN2, STEVEN E. JASINSKI2 AND TRACY L. FORD
"A reconsideration of the ichnotaxonomy of large ornithopod footprints suggests that only two
ichnogenera may be valid: Caririchnium (= Hadrosauropodus) and Amblydactylus (= Iguanodontipus)."
Monday, 26 May 2014
A crummy track or an artifact: that is the question
Forgive me for paraphrasing Shakespeare's Hamlet in the heading of this post, but it all comes to that simple question when in dilemma about the true nature of a dinosaur (or any other) track.
A strict palontologist would probably discard the possible theropod footprint from the photograph below as being to crummy to make sure.
On the other hand, a find like this is open to discussion. According to my scale I would grade it as something in between a probable track (**) and a poorly preserved track (***). However, you can't exactly see in this photograph what made me determine such a grade. I have also found other similar prints on that particular very weathered layer, plus possible prints of a sauropod and a crock, and several prints left by the pterosaurs. All of them are rather poorly preserved, except one particular manus pes set from a rather large pterosaur. Even more: that pterosaur track is a part of a trackway.
Something else is also interesting about the photograph above. You'll notice the moder tracks being left recently in the soft mud (upper left corner). Of course, these are never going to be preserved, because they will be weathered very soon. However, if they were old and if they had managed to get preserved how would you grade them? Can you recognise the track makers?
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