A quiz question: Who left this track?(2)

Guess the tetrapod from the track!
 ... and the answer is: a large iguanodontoid
 

 In the image above:
1) Iguanodontian track from the Main Brijun island. Probably left pes footprint. Note my feet size #46 at the bottom of the photograph.
2) A close up of the hoof (ungual) #3. Note the similarities of the print (cast) with the Romanian true ungual fossils (Fig.4). Note that the base, or the distal part of the ungual also left an impression. In fact, I have discovered that a rather well defined toe impression of an iguanodontoid track maker often preserves and thus could be considered a diagnostic feature.
3) My interpretation of the footprint - red outline.
4) Iguanodontian ungual #3 from Romania, Early Cretaceous (left-bottom; right-top of the hoof), from this paper:

 IGUANODONTIAN DINOSAURS FROM THE
LOWER CRETACEOUS BAUXITE SITE FROM ROMANIA
ERIKA POSMOŞANU
ACTA PALAEONTOLOGICA ROMANIAE V. 4 (2003), P. 431-439


As for the results of the Quiz. There's no winner. Nobody even tried guessing. So, am I just imagining things?

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)."

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?

Farlow's Three Laws of Dinosaur Ichnology

 When in the field, almost nobody is immune of being tempted to over interpret the possible dinosaur tracks. I have experienced it on my own skin. Like I have said so many times before, finding the perfectly preserved tracks is a rather rare and special event, probably equal to finding dinosaur fossil bones. In reality, you are most likely to finding an array of poorly preserved, single and atypical ones. This shouldn't be surprising, if you consider all the dinosaur genera that existed and their various size classes, that might have left the tracks; all the actual conditions under which the tracks were preserved and the time span and erosion that the tracks underwent until being discovered. My advice (B. Krzic) is not to be too enthusiastic about every possible track, nor overly conservative. You'll often find yourself in a situation of  either being tempted to interpret some geological artifacts as tracks, or discarding some interesting real tracks as artifacts. If you don't really believe you had found a real track, basically you won't be able to convince the others either. So, the first and the toughest step in identifying and defining a track is convincing yourself it is a real track.
If you want to play it safe, you should definitely follow my friend Jim's "Three laws of dinosaur ichnology", which he had devised with a great dose of knowledge, field experience and humour.

Dr. James O Farlow is a professor of geology at Indiana University and one of the leading experts in dinosaur ichnology.



Some of Albert Einstein's quotes for which I thought would fit in this post:

A person who never made a mistake never tried anything new.

Imagination is more important than knowledge.

The only source of knowledge is experience.

No amount of experimentation can ever prove me right; a single experiment can prove me wrong.

The whole of science is nothing more than a refinement of everyday thinking.

Nature shows us only the tail of the lion. But I do not doubt that the lion belongs to it even though he cannot at once reveal himself because of his enormous size.

A scientist is a mimosa when he himself has made a mistake, and a roaring lion when he discovers a mistake of others.

With fame I become more and more stupid, which of course is a very common phenomenon.

If we knew what it was we were doing, it would not be called research, would it?



KRZIC'S SCALE FOR GRADING DINOSAUR TRACK QUALITY:

• - ARTIFACT ......................................... - 1  ..............  --
• - PROBABLE ARTIFACT ....................   0   ..............  -
• - POSSIBLE TRACK ............................  1   .............  *
• - PROBABLE TRACK .........................   2   ..............  **
• - POORLY PRESERVED TRACK .......   3  ............... ***
• - WELL PRESERVED TRACK ............  4   ............... ****
• - PERFECTLY PRESERVED TRACK..  5   ............... *****

Definitions are yet to be written.

The iguanodontoid tracks from the Main Brijun island

You can download a free PDF of the official brochure for the dinosaur tracks of the Brijuni islands
(... in the production of which I wasn't involved): Promenade of dinosaurs .

In the photograph below is presumably one of the iguanodontoid (left pes) footprints on the peer of the Main Brijun harbour. The yellow outline is my interpretation. Track is about 32 cm long. Note the pointed toe #4 impression.

The probable, very shallow iguanodontoid tracks in my photographs are from the Pogledalo promontory of the Main Brijun island. My interpretative drawings are on the right. I have placed my interpretation in red outline from the bottom picture, over the yellow outline in the upper image for comparison. It seems there's a manus impression between the toes #3 and #4 of the right pes. Note the pointed toe #4 impression, just like in the footprint on the peer.The footprint is about 55 cm long.

The iguanodontoids and sauropods would present a perfect prey for the large theropods that left their footprints on the same promontory.

Kamenjak ornithopod

There is an upper layer on the Grakalovac (Kamenjak #1) site, that has preserved tracks, too. I wonder why nobody has checked it out, yet. Just at a superficial glance I have spotted a nice, very small ornithopod footprint - in fact a natural cast, just about 12 cm long. I took a better look and there were a couple of poorly preserved tracks that formed a small trackway of apparently slowly walking dinosaur. See my photograph and interpretation outlines.

Whether this trackway was left by a juvenile or adult animal, nobody can tell. There are also some poorly preserved theropod tracks on that rock layer near by.

Face to face with a true Godzilla

During the recent stay in Thailand I took the opportunity to take some photographs of the living archosaurs. I shot this image fearlessly facing this mini Godzilla (which was "only" about 3-4 meters long by my estimate). O.K. I admit there was a bit of help from a zoom lens ;-)
The crocodile tracks are rather rare in the Cretaceous rocks of Istria. I managed finding only a few.

I guess this film looks funny to today's movie goers. However, I assure you, it was scary for me as a kid back in the early 60's. Maybe we did have more imagination?

A quiz question: Who left this track?

Guess the tetrapod from the track!

The Cape Pogledalo, Main Brijun island (V. Brijun) site.

  

To tell you the truth, at first, while looking at it in situ, I miss interpreted the impression in the photograph below. Only back at home when analysing the photograph on my PC, I have concluded I had been totally wrong in my attribution. It is not a typical footprint example for the particular ichno family. So, this task is really a tough one! A specific diagnostic feature made me change my initial speculation. After that I spotted the other characteristic features, that were not that obvious at the site but which confirmed my thoughts. Although, this diagnostic feature is not always present in the footprints of these dinosaurs, it helped me resolve my dilemma quite a few times.

  

I'll give you a couple of hints: The site is the Cape Pogledalo on the Main Brijun island (Istria, Croatia), of the Barremian age (early Cretaceous), described in the paper by Dalla Vecchia ; this print was not described in his paper. Note the tip of my shoe (#46) on the right for size. When watched from the side, the track looks like a large shallow bowl. By the icnology standards the footprint is poorly preserved (except one crucial detail).

I challenge the ichnologists to give the answer and the clues in the comments. What kind of animal left this print? 

 Of course, after some time I'll reveal my interpretation and the  diagnostic hot spots.

The usual suspects are: A) theropod, B) sauropod, C) stegosaur, D) ankylosaur, E) iguanodontoid, F) croc, G) pterosaur, H) turtle, I) lizard, J) bird, K) mammal, L) fish

Please, select one of the answers and post it via Comments below:

Grakalovac theropod tracks mystery (2)

Here is Fabio's (Dalla Vecchia et all, 2001) map of the Grakalovac (K1) site. In my opinion it is incomplete because the important (new?) tracks are omitted. The photograph below is turned upside down for coordinating the map's view point and the map's contents. "B" and "C" stand for the footprints and their track makers (see my diagram in the previous post). "S" stands for the undefined sauropod or/and ornithopod tracks.

In the mosaic photograph below are the tracks and the pace lengths of Grakalovac theropods arranged by size, growing from left to right. In this case, it seems the smaller the theropod, the relatively longer pace.

The next mosaic photograph are the closeups of some individual prints. "D" is mostly in-filled outline of the track. The track marked with "D" is outside the map area. "S" is apparently an oval shaped manus-pes set  of a very small sauropod. The pes has the drag marks behind it.

Although at the first sight the image in the first row below appears to be medium-sized, it is in fact just a partial print, missing a good deal of the heel. This prints is also outside the Fabio's map. In the right is the enlarged and superimposed red outline of the "C" print. It is revealing the true shape and size of this print (about 36-38 cm long).
The bottom row is the "D" print again with the interpretation on the right.

More to come in one of the posts to come: Are the peculiar tracks on Grakalovac, hadrosaur baby tracks or the prints left by a very small ornithopod ?

Grakalovac theropod tracks mystery (1)

 Kamenjak theropod lineup

When comparing my finds, photographs and measurements from Kamenjak 1 and 3 (I had discovered two more tracksites on Kamenjak, so I have named the sites K1, K2 and K3), with the data and conclusions from Fabio's (Dalla Vecchia et all, 2001) paper Dinosaur track sites in the upper Cenomanian (Late Cretaceous) of istrian peninsula (Croatia), describing the tracks from Grakalovac promontory (Kamenjak 1 or K1) something just doesn't add up. Many new questions and speculations appear. Here are some of my thoughts regarding this problem:
1. The theropod morphotype with a relatively very long  middle toe (#3) is reminiscent of an ancient theropod trait going all the way from the late Triassic and early Jurassic (Anchisauripus, Grallator, Brontozoum). Given that in general theropod feet are rather conservative and that they have not changed much over the 100 million year span, this can be plausible. I have already concluded that the tracks on Grakalovac were probably left by a ceratosaur or a compsognathid.
2. Dalla Vecchia has noticed and featured in his paper two size classes of theropod tracks on Grakalovac (K1), both being the same or very similar morphotype.  It seems that Fabio and his colleagues either didn't notice the other tracks, or more likely that the erosion has uncovered these new tracks during the past 14 years. I have noticed several new tracks, some of which were quite unusual. Among them are the ones that look like belonging to a baby hadrosaur.
3. It is a consensus that Istria and some other parts of ADCP was by the Cenomanian (Late Cretaceous) large island with the dwarf insular dinosaurs inhabiting it. That's where my large-foot theropods from K1 and especially K2 don't quite fit in. Or do they?
In the diagram below is the Kamenjak theropods lineup. The little brown silhouette is the Chinese "large compsognathid", with the foot about 11-12,5 cm long (A); marked with (B) is the small Grakalovac (K1) theropod from Fabio's paper and my photographs with a foot 16,5-17 cm long; (C) is the larger specimen from the paper (K1) and (D) is the largest track maker from K1 with the foot 38-40 cm long. The yellow silhouette (E) is the giant with the similar foot shape from the K3 track site, I had discovered last year. Its foot was around 65-67 cm long. 

3. So what is strange with this "insular" ichnocenosis is the obvious presence of very large theropods. I could settle with the 5-meters long one as one of a plausible size (D), but my discovery of the footprints which translate into a 8-10 meters huge beast (E) made me wonder: Am I seeing things? Are my interpretations wrong? Maybe the tracks were deformed? Maybe these were over sized under tracks? So far the evidence speaks in favour of true tracks.
4. Diminishing size or regression in growth of once large insular herbivores in order to compensate for the reduced food sources and maintain the viable population is a well documented biological scenario. So far, the evidence (tracks of herbivorous dinosaurs in Cenomanian rocks of Istria) speaks in favour of the pygmy island dwellers.Those were the small sauropods and small ornithopods.
How do the large theropods fit in here? Maybe they were oriented towards the sea based food? Fish eating dinosaurs? Like the spinosaurids. In any case, I do speculate that the small sauropods had to have some form of defence against the fierce giant predators. Maybe they were heavily armoured like the ankylosaurs? It is even possible that we still didn't find the tracks of the larger Cenomanian Istrian herbivorous dinosaurs.
One thing is certain: We will continue researching and learning new things about dinosaurs and their fantastic, mysterious world.

Back to Grakalovac (3)

It is a bit strange but the small theropod track morphotype fits the really ancient theropod foot bones. The one by the late Triassic Coelophysis. I speculate that these footprints were maybe left by a ceratosaurid or possibly by a compsognathid. The "large compsognathid from the early Cretaceous Yixian formation of China"  Huaxiagnathus is almost big enough to be a suspect. It's foot is only about 25% shorter than this Grakalovac (Kamenjak 1) diminutive theropod footprint. The proportions of the toes are quite similar. So our mini theropod might have been some close relative of this Chinese predatory dinosaur.

The articulated Huaxiagnathus feet in profile, from the paper.

Marvelous looking flat exposed rocks on the Grakalovac promontory. The view from a higher track baring outcrop. Some of these feature ripple marks and some of them still hide other tracks and traces.

Back to Grakalovac (2)

To continue from the previous post, here is the second footprint (right pes) of the small theropod from the Grakalovac promontory...

... and here is the pace length (photograph below, with my red outline interpretation). Indicates a rather slow walk of a long-legged theropod:

Back to Grakalovac (1)

When tracks and traces are in question, best thing to do is to visit the sites more than once, preferably under different weather conditions, different time of day and different season. Especially in the case of poorly preserved and faint, barely visible tracks, the repeated visits will produce often surprising results. What's more important, the multiple observations will produce better results that are closer to the true. That said and after making new photographs, my Grakalovac (Kamenjak) giant thyreophoran is unlikely.
On this photograph taken from the official Kamenjak park site, the low sunshine implies multiple smaller prints instead of a single giant one. Yet, it is hard to determine their maker. They might be from a sauropod, like suggested in papers by Dalla Vecchia, Mezga and Bajraktarevic. Also, they might belong to a slowly moving ornithopod or a quadrupedal thyreophoran, or something entirely different. We'll probably never know for sure. The prints are rather inconsistent in shape and pace. The only thing that is certain about them is that they were made by a tetrapod. Maybe it wasn't just one animal, although, the grouping of the prints is suggesting that.

Here is my recent photograph of the "mysterious" Grakalovac prints, with my red outline interpretation/speculation. After analysing the photograph, this time it seems to me, there are a couple of small quadrupeds. Maybe the baby sauropods or really small pygmy sauropods whose tracks are mixed with the medium-sized ornithopod (green outline) who crossed this mini dinoturbation spot a bit later, when the substrate dried up a bit. But still the "ornithopod" slightly obliterated trackways left by the parallel walking "sauropods". The red arrow shows the direction of the tracks. Still, the tracks are so poorly preserved that my interpretation is highly speculative. You might have noticed that visually this mini dinoturbation suggested different direction of movement than my interpretation.

To my relief, I have found some theropod footprints close to this spot and there's no doubt about the trackmaker's foot shape and size. In the photograph below is one of the prints of the "cute" theropod with a foot 16,5 cm long (the animal was probably around 2 meters long).
The impression of the halux (toe #1) is clearly visible (forward oriented) as well as the claw prints on all the other toes.

Ankylosaur dinoturbation

About a hundred meters down the beach, from the dinoturbation where the sauropod tracks prevail (where the iguanodontoid track from my previous post was photographed), at roughly the same level is another dinoturbation. It's also brecciated, but it seems that thyreophoran tracks are predominant. There is also a track of a giant theropod there and of a few smaller ones.
In the photograph below is one of the better preserved pes tracks. It is a cast of apparently the right pes. Roughly 45 cm long. It is a part of a poorly preserved trackway which stretches some 15 meters.
Parallel to it is another trackway left by the animal of the similar size. At the end of the trackway are a few huge, probably thyreophoran pes prints. It seems that there are also tracks of juvenile ankylosaurs present. The three size classes of the same type of dinosaurs, on the same site, might indicate a structured gregarious behaviour.
In the image on the right is my interpretative red outline and the black outline is Sauropelta right pes track interpretation from Carpenter.

A more recent research at the site revealed that this was in fact the right manus print (natural cast) of the large ankylosaur. The pes track is partially visible in the left corner of the photo.

Large iguanodontoid track

Here we are back on a Pula beach (late Albian). This is the same sauropod dinoturbated site where I have found a couple of speculative "stegosaur" prints (which in fact might just be the small sauropod ones - see my previous posts for details). What you are looking at, I believe might be a partial print of a large iguanodontoid pes (a natural cast). I have found indications of more prints of the similar size near by. Unfortunately, none of the prints is a "perfect" specimen that would make everybody convinced. The dinoturbated, brecciated surface is full of large and small sauropod tracks. There are also some theropod tracks.
For scale: the little black bag is 13 cm long and you can see the tip of my sandal and toes in the left upper corner.

The first nudists on Solaris beach

Actually, the heading of this post is probably erroneous, because the small to mid-sized theropods were almost certainly not naked, but dressed up in their fancy "dino fuzz". However, there's no question about it that they were the first ones to occupy these wonderful beaches near Porec, around 100 million years ago (late Albian, Early Cretaceous). Fact is that the countless dinosaur tracks "litter" the long beach of the large Istrian naturist resort  Solaris.
To take these photographs without being surrounded by the naked people, I had to visit the site in December.
See one of my previous posts: "Small sauropod footprints at the beach" for more information.
In the photograph, you can see the "messy dinosaurs" again. There are numerous footprints in this image alone, in various states of preservation. I tried to outline the best ones. The largest theropod prints measure some 28-29 cm in length. So, I presume the animal was up to 4 meters long.
In the centre, there is a brown outline of what seems to be a small ornithopod. I think this print is not what it seems (see my post about the tracks on Kamenjak). In fact, this is just the mid section of the theropod track that got preserved in the "paleo-sand". Of course, the tracks were left in a fine wet sand, which is now a hard carbonate rock.

Happy International Labour Day!