An ankylosaur trackway destroyed in Pula

I have just returned from a trip to Pula. It is sad, but a few of my photographs is the only thing that has remained of the first ankylosaur trackway in Pula, Croatia (the Adriatic-Dinaridic carbonate platform). I had discovered the tracks in 2011 and I didn't even manage to write the paper. The trackway, which was situated at one of the most frequented beaches in Pula has been covered with a thick layer of concrete for sunbathing. There are more tracks on that particular beach, but just one trackway that runs parallel to this one was preserved enough for research to be conducted. I fear that one is going to be destroyed as well in order to make the beach more comfortable for the numerous tourists. A few years ago I tried to warn the government institution State Institute for Nature Protection about the valuable, numerous trace fossils that are in the danger of being damaged or destroyed, but in vain. This isn't the first case of this kind either. Recently, the theropod trackways have been destroyed and damaged out of ignorance and negligence in Lovrecica, Istria, Croatia. News coverage of that event. That Lovrecica tracksite was even described in a scientific paper and should have been protected.
It is ironic, but I am probably the only person aware of this latest loss.
The "fossil of the fossil"- my photograph of irreversibly lost valuable piece of palaeontological natural heritage in Pula:

Latest news (August 2014): good ones (for now)!
Recently, I've visited this site and discovered that the concrete missed these two tracks (in the photo above) for about a meter. They are still there, but were covered with a muddy water. That's why I didn't see them during my previous visit.

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?

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.

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:

Dinosaurs were messy ... (3)

Here is an example how hard it can be to correctly identify the tracks. I have photographed a small fraction of the Barremian (cca 125 mya) dinoturbation at the Pogledalo promontory of the Main Brijun island in Istria (Croatia).
Outlined with the red line are all the visible theropod footprints. A very large single foot impression is only partly visible under the covering sediment. Applying Dalla Vecchia's ideal footprint model of the theropod from that site (the green silhouette) I managed deriving the track size of that particular theropod. It was bout 65 cm long. The beast itself was at least 10-11 meters long. The size of an adult  Altispinax. Other footprints are from considerably smaller individuals. The prints were distorted due to the mud collapse. There are at least 8 theropod footprints in this photo. Probably more.

Monster iguanodontoids

  

Pula, Istria, Croatia, late Albian (mid-Cretaceous)

About a 100 million years ago, the beaches near the city of Pula (which itself has about 3000 years long history) were sandy and muddy and the sea was shallow. The rudist clams formed some sort of rudist reefs not far from the coastal line. The stromatolites colonies were sticking out of the water, while the large sturgeon or/and guitar fish probed the mud for food swimming the shoals. Small, large and huge dinosaurs, crocks, monitor lizards and pterosaurs left their footprints in the wet sand and sticky mud.

  Many years later, the old beaches turned into multilayer limestone rock, looking like some sort of a giant book. The ancient archives with the notes of the the life long gone,waiting for the sea to uncover them and somebody interested and inquisitive to read the fossil "hieroglyphs".

Here are the pes footprints of the immensely large iguanodontoid. I am standing on the convex  left pes with infilling, while photographing the concave right pes (footprint) in an oblique view. My yellow outline marks the impression. The displacement rim is quite nicely visible, as well as the mud suction traces along the mid line. Each of the prints measure unbelievable 135-145 cm in length. I don't think there was a larger iguanodontoid print discovered anywhere in the world, so far. Yet, these prints are situated on one of the most popular and crowded beaches near Pula. I've stepped over these prints so many times myself over the years without noticing them. Why? Simply because they were so enormous, that they were too difficult to spot and figure out as once belonging to a living, breathing animal. The ornitischian who left them in the wet sand must have measured at least 18 to 20 meters in length! (See the comparative sizes in my banner)

Giant ankylosaurs

  Here are the pes footprints of the two giant ankylosaurs (not to scale) with my interpretations on the right:

Pula Albian (mid-Cretaceous) ankylosaur right pes lenght: 85-95 cm (A, B) - I am standing on it's toe #5 of it's four pes toes;

Tumbler Ridge (Canada) late Cretaceous anky has a scale of 10 cm for size comparison (about 44 cm total pes length) (E, F) Photo credit: Rich McCrea. 

 I know it sounds unbelievable, but the Pula ankylosaur, as derived from the size of the largest pes footprints (there are at least 6 of the foot impressions at the Pula site) must have measured some 14-16 meters in length (!)  In a way it wasn't that surprising to me, since all of the super mega fauna members from Pula site were world record holders. Check out my title banner: these are the ultra dinosaurs from Pula in scale (!) They were gregarious, as it seems from the fossil record. Maybe comprising of small family groups. A pair or more adult dinosaurs guarding and taking care of their offspring.
It is interesting that some members of  Thyreophora - a subgroup of the ornithischian dinosaurs
which include well-known suborders Ankylosauria and Stegosauria, had diverse number of toes.
While some of the ankylosaur ichnogenera had three, the others had four toes on their hind feet.
Thus it is possible to miss identify the thyreophoran three-toed pes tracks for iguanodontoid ones and vice versa, especially if the front feet impressions are missing or are poorly preserved. Despite of the enormous record size of the Pula, Istrian tracks it is less likely that these were artifacts.

The Tumbler Ridge site

Late Cenomanian theropod tracks

  Last year (2013) I finally visited the track site situated on an Istrian natural reserve park the cape "Kamenjak". There are Late Cretaceous (late Santonian) dinosaur tracks all over the place, but the best preserved are on the Grakalovac promontory, on the beach, near the entrance to the park.

A nice medium-sized theropod trackway is marked with ugly black circles (A). My interpretation (B). However, there are more theropod footprints scattered all around. See one in filled with the sediment (C) and my interpretation with a couple of more less preserved prints (D).
The larger tracks that nobody could identify so far, are also marked with black circle. They seem to me like the prints of a fairly large ankylosaur. More about it in the next post.


The Italian paleontologist Fabio Marco Dalla Vecchia wrote extensively on the dinosaur fossils in Istria. Here is one of the papers.

A sauropod right pes on a building block

 A sauropod right pes on a building block of the Early Cretaceous limestone at the pier near Pula (Istria, Croatia)

I don't remember if I said it before, but Istria has been literary "littered" with the Mesozoic fossils. The dinosaur tracks can be considered as numerous and omnipresent. Which doesn't mean they are easy to find by laymen. One has to learn distinguishing them from common artifacts. The limestone erosion is prone to forming very rich array of shapes.

So, here I am, walking along the beach and looking for some familiar shapes. I get awarded quite often. Here is a nice sauropod (probably a titanosaur) right hind foot print on a building block. The production process in the quarry left it in a rather good shape. Although, the block looks slightly "flawed" because of the dinosaur impression. The photograph was taken on February 15th 2014. Red outline helps you visualise the print. There is a low displacement rim in front of the track, where it should be. The pes measures about 60 cm in length, representing a decent size track maker sauropod. The largest sauropod hind footprints I've found there measure about 130-140 cm in length. Those were true giants! 

Finding dinosaur tracks on building blocks is not that rare either. I've found many myself. Some of the tracks were found by Dalla Vecchia, as described in his paper.