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.

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.

Tracks, tracks...everywhere (3)

I don't know if I have been clear enough, so far. This cape Kamenjak track site is NEW and has not been described yet. Nobody has noticed nor detected these Cenomanian dinosaur tracks. I call it "Kamenjak 3".
I've been analysing my photographs from this site and the site that was described to a certain degree in Fabio's (Fabio Marco Dalla Vecchia) paper (Grakalovac promontory), which I have named "Kamenjak1" and all my finds lead to this conclusion: In Cenomanian (late Cretaceous), Istria was a part of a large piece of land (Adriatic Dinaridic Carbonate Platform - ADCP) sustaining viable populations of various types of big dinosaurs. It was either a very large island or still Afro-Arabic  peninsula. Not only that I speculate that a large tyreophoran track is present on Grakalovac (see my previous posts), but it seems quite big ankylosaur was present on this new site, too. While this is still just a possibility because the tracks are poorly preserved (one is outlined, while the other is under my foot), the  theropod footprint beside them speaks for itself. The largest one was some 73 cm long. The print is shallow, because the substrate was already quite dry when it was made, so it effected the mud cracks. The "owner" of the foot must have measured at least 9-10 meters in length! I have outlined the probable prints.

Here is the size and shape comparison of the theropod tracks from "Kamenjak 3" site (red bar is 12cm long). The largest footprint is from the photograph above.

Tracks, tracks...everywhere (2)

I've been to Pula over the Easter holidays, but didn't have time to visit the Kamenjak sites. However,
I tried to analyse the old photographs once again. Here is the result (below). I am positive now that the mid footprint was no ornithopod but a fairly large theropod with very long middle  toe (#3). A smaller theropod (green outline) was crossing diagonally the path of the large one (or vice versa).

In Pula, the first tourists are sunbathing and even swimming in still rather cool sea.

Tracks, tracks...everywhere

The tridactyl dinosaur footprints are omnipresent in the Cretaceous laminated sediments of Kamenjak. The problem is: they are not that easy to spot. Nor they are easy to define, because they are in a different state of preservation left on a varying substrate. Imagine a mud flat. The tide has just receded. The first dinosaurs to cross the mud will leave deep, often collapsing tracks. As the mud dries, the next tracks will be less and less visible. Dinosaurs step over the tracks left by the other dinosaurs (or themselves) earlier, making them deformed. The waves start to wash the shore. Some of the dried tracks will be erased, some will remain and get covered with the sand and mud. The trackways are often messy.
Here is an example of a dinoturbation with various types of tracks. I tried to interpret some of the tracks with the red outline. It seems that at least three kinds of theropods left their footprints. Of course, I couldn't see all the prints. It's hard to notice them and take photographs with a digital camera on a bright sunny day with almost white rocks reflecting light from all sides.

A close-up with somewhat different interpretation of the tracks in the middle of the outcrop (below).
The footprint is about 45 to 48 cm long. If my interpretation is correct, that transfers into a 6-7 meters long predatory dinosaur. You wouldn't want to meet such a beast! The other theropod was obviously much smaller.

A photograph of the Kamenjak's carbonate rocks below. These rocks are hiding hundreds if not thousands of Cretaceous tetrapod tracks for those with enough time, patience, determination and most important a good eye to discover and describe them.

A look back at the Porer islet with the lighthouse which is behind us now. We are walking towards the tip of the cape.

Back to Kamenjak

If you don't mind the heat, the south Istrian cape (rt) Kamenjak is a nice place for trekking and observing the nature in Spring time. You may even get lucky and see the extremely rare monk seal.
It is too hot for me to walk during the Summer, but there are plenty of nice beaches to go to swimming or snorkeling. The islet Fenoliga which has numerous (although weathered) dinosaur tracks is visible in the distance, between the cape on the left and the light house (islet Porer) on the right. One can see the rudist fossils along the way.
While walking towards the tip of the cape I have noticed an interesting rock in a farm's wall (suhozid). It looks to me it might be an impression of a late Cretaceous plant. See below, far left in the photograph. I'd appreciate if any of the blog readers can help me out in identifying the fossil (or is it just an artifact?) Could it be the mid-Cretaceous angiosperm Sapindopsis angusta? In fact, it resembles some kind of psilophyte plant. The environment was supratidal-intertidal  with extensive mudflats, where dinosaurs left their tracks. There were rudist reefs and  stromatolites in the shallow sea of the lagoons.
Maybe it was some kind of an algae washed ashore (?)

A common sight at Kamenjak are sheep herds.

In some places, the path gets quite narrow because of the rich flora.

And here is the view at the Fenoliga islet. So close, but out of reach if you don't have a boat.

Fabio's paper describing the Istrian Cenomanian tracks. Kamenjak and Fenoliga sites are included.

Here are the Istrian Cenomanian theropod prints (outlines) from the paper:

A few of the footprints have a "fat" middle toe (toe # 3) padding. Below is the photo and my footprint interpretation of another theropod track from Kamenjak's outcrop just across the Fenoliga islet. There are at least two more prints of the same dinosaur at the site. None of the images above fit to that morphotype. The foot is about 34-38 cm long. I am not sure about the heel: is it all heel or also a drag mark?

Notice the unusual shape of toe #4. At first I had thought it was a substrate deformation due to the footprint pressure, or some sort of a drag mark, but than I saw the other prints had the same feature. Maybe it's not a theropod at all. Maybe it's an ornithopod track.

After all, the emerald sea looks inviting!

More Istrian theropod tracks

More often than not, the dinosaur tracks are almost invisible to an untrained eye. Here are a couple of theropod tracks from the Cape Kamenjak (the Grakalovac Promontory), near Premantura, Istria, Croatia.  The site is of the Late Cretaceous age (Cenomanian). My interpretation is the yellow outline on the right. The upper and lower images are not to scale (note the size of my foot for reference).
Of course, there is a chance one can misinterpret an artifact for a true track. If there are more footprints on the rocky surface you are surveying, the better chances are the questionable ones are genuine as well.

Measuring points for a right theropod footprint. For the left one, you just flip the image.

 Some of the better preserved, more visible tracks from the same site were described in the paper free to download.