Monday, 31 March 2014

Dinosaurs were messy ... (2)


If you were suspicious of my theropod tracks interpretation from the previous post, here is a photograph from the same outcrop showing a rather poorly preserved (possibly consisting of under prints) theropod trackway of the animal that had the same shape and size of the foot.


The tracks on the right don't have the distinctive features, so I couldn't figure out their makers (yet).


Sunday, 30 March 2014

Dinosaurs were messy ...


... when leaving their tracks!

So, you have decided on finding your own dinosaur tracks? The ones nobody has noticed yet? Or at least nobody has  announced his/her finds publicly. You are expecting to find a nice trackway on a relatively flat rocky surface? Possibly three-toed nice and clear theropod footprints in a sequence? Yeah, right! Chances of finding a track like that are almost equal to finding a nicely preserved relatively complete and articulated fossil skeleton. 
Take a look at the muddy paths where humans and animals left their traces today or yesterday. Are these all well defined traces? Come back in a week and see what's left of them. Consider that dinosaurs left their tracks millions of years ago...

Here is my attempt of interpreting some (probable) theropod tracks from Pula, that are about 100 million years old. They were preserved during the low tide.



Thursday, 27 March 2014

Tyrannosaurus rex feeding habits


 In case you've mised this here is the recent post from my gag cartoons site Oberon Cartoons
 T.rex and his paleo diet

Here is my new paleo cartoon, not to be confused for a paleo diet. It's dealing strictly with Tyrannosaurus rex feeding habits. If you want the paleo diet recipes, please, go elsewhere.





Friday, 21 March 2014

My old view at the good old T.rex

Here is my quarter of a century old Tyrannosaurus rex painting. If you look at it carefully, you'll notice the "fleshy" lizard-like lips on the beloved theropod. Given an even a closer look at the painting, you'll notice a few water birds in the background. The birds caused sort of a commotion among the visitors, who thought they were educated in the issue, at the opening of the exhibition of my prehistoric animals paintings at the Croatian Natural History Museum in Zagreb in 1994. Most people knew only about the Archaeopteryx as the sole Mesozoic bird at the time, so my intentional provocation with the duck-like birds hit the chord. I know that this sounds like a joke today, but the greatest bird (and dinosaur) discoveries were yet to come.
Also notice the legs are not in a (popular) squatting position, but more errect, which does make sense for the animal of that size.
The painting was produced in gouache in 1988 and it has been in the collection of the CNHM in Zagreb since 1991.





Thursday, 20 March 2014

Deja vu: "Chicken from Hell"

I don't know who coined this fossil "Chicken from Hell", but I am sure the media had to invent an "attractive" title for the dinosaur discovery, to make it stand out from the rest of the gloomy news from the World and yet fit into the mood. Since the fossil in question is from the famous Hell Creek formation and looks a lot like a mutant chicken, armed with the nasty hand claws, the title is quite appropriate. The only thing about the "news" is that it is not so new.
In fact, the CNHM paleontologist Matt Lamanna and the other authors have finally  published a paper that presents the first decent look into the complete morphology of caenagnathids.
Anzu wyliei was a peculiar looking, bird-like dinosaur that had a bony crest on top of a beaky head and relatively short tail for a theropod.
The animal has been identified from the partial remains of three skeletons collected in North and South Dakota that have been known for a while. In fact, my restoration of this caenagnathid in the image below is about 10 or more years old.
When all fossils are combined, about 80% of the skeleton is now known. Which is incredibly complete by the paleontologists standards. The animal lived some 66 million years ago in the biota where Tyrannosaurus rex was the top predator. Being 5ft high at the hips (150 cm), the giant "chicken" presented a danger for the smaller dinosaurs and other tetrapods of the time.
All three Anzu skeletons are housed at the Carnegie Museum of Natural History in Pittsburgh, which collaborated with the Smithsonian to identify the new species.
Here is the free paper:
 Matthew C. Lamanna, Hans-Dieter Sues, Emma R. Schachner & Tyler R. Lyson (2014) A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous
of Western North America. PLoS ONE 9(3): e92022. doi:10.1371/journal.pone.0092022

  Abstract: The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs.

My old restoration of the caenagnathid (Krzic 2002?)


Another link to the news.




Tuesday, 18 March 2014

A theropod track from Pula


  
A theropod track from Pula

Here is an interesting shape of the large theropod footprint from Pula (Albian - early Cretaceous), I have found recently. At the first sight it looks like some giant bird's track. In fact it is the collapsed mud/sand impression that was probably partially washed away by the tide (the outcrop features the long low crested ripple marks). The possible second footprint is only barely visible in front and a bit to the right from the first one in the photograph. The length of the track is about 46 cm. The animal was probably some 6 to 6,5 meters long.
The same outcrop has preserved the small theropod prints; the giant pterosaur manus prints; small and medium sized pterosaur footprints; medium-sized sauropod tracks and huge iguanodontoid footprints.


Friday, 14 March 2014

Emperor of the North Pole: A Dwarf Tyrannosaur

A Pygmy tyrannosaur was one of the top predators of the late Cretaceous North America's high latitudes. It is speculated that the diminutive size was an adaptation to the harsh polar climate. There is almost no doubt, although no physical evidence was recovered, that the theropod had been covered with proto-feathers, or so called "dino-fuzz".

A free paper:

 Anthony R. Fiorillo & Ronald S. Tykoski (2014)
A Diminutive New Tyrannosaur from the Top of the World.
PLoS ONE 9(3): e91287.
doi:10.1371/journal.pone.0091287

 Abstract

 "Tyrannosaurid theropods were dominant terrestrial predators in Asia and western North America during the last of the Cretaceous. The known diversity of the group has dramatically increased in recent years with new finds, but overall understanding of tyrannosaurid ecology and evolution is based almost entirely on fossils from latitudes at or below southern Canada and central Asia. Remains of a new, relatively small tyrannosaurine were recovered from the earliest Late Maastrichtian (70-69Ma) of the Prince Creek Formation on Alaska's North Slope. Cladistic analyses show the material represents a new tyrannosaurine species closely related to the highly derived Tarbosaurus+Tyrannosaurus clade. The new taxon inhabited a seasonally extreme high-latitude continental environment on the northernmost edge of Cretaceous North America. The discovery of the new form provides new insights into tyrannosaurid adaptability, and evolution in an ancient greenhouse Arctic."

*****

By the way, one of my favourite old movies:
Emperor of the North Pole (the title was later shortened to Emperor of the North) from 1973. It is an American film directed by Robert Aldrich and starring Lee Marvin, Ernest Borgnine, and Keith Carradine. The poster for Italian distribution:


Thursday, 13 March 2014

Some of the track makers from the Main Brijun island


  
The Main Brijun island, Istria, Croatia, Cretaceous

Here are a few of the track makers from the main Brijun island (Veli Brijun), Istria, Croatia. At the top is the large Barremian (early Cretaceous) theropod. It's footprint is 62 cm long. The animal was probably about 8 meters long. In the middle is an iguanodontoid with a footprint 56 cm long.  The dinosaur would have been about 8 meters long. Both are from the Pogledalo promontory. At the bottom is the late Santonian (late Cretaceous) hadrosaur from the Pljesivac (Kamnik) promontory. 



Monday, 10 March 2014

The Ice Storm Aftermath

 
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A walk through the park (Roznik) near Ljubljana a month after the ice storm ("zled").

At the bottom of the hill, the broken trees are not so numerous.


 Soon after beginning the climb following the forest path, the full extent of devastation becomes visible.



Approaching the top of the hill the damage becomes ever more evident.




The impact on the fauna is not known yet.
It'll probably take at least a couple of decades to heal the Slovenian woods from this natural catastrophe.



Friday, 7 March 2014

Dinosaur news: The Largest Terrestrial Predator from Europe


In the New PLoS ONE journal, Christophe Hendrickx & Octávio Mateus published the discovery of a giant European theropod (the fossil maxilla) from the Lourinhã Formation (Kimmeridgian-Tithonian) of Central West Portugal. The Formation " is well known for its diversified dinosaur fauna similar to that of the Morrison Formation of North America; both areas share dinosaur taxa including the top predator Torvosaurus, reported in Portugal."

Here is my (really quick) sketch of how the dinosaur may looked like in life:

 
 
Of course, Triceratops in my logo is not here for the scale :-) 

Free paper: Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian Theropods



Wednesday, 5 March 2014

A Quaternary digression


 

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A  skeleton of a small Quaternary horse in a breccia in the midst of the Cretaceous rocks

It is interesting that many Cretaceous limestone sediments have gaps which are filled in by the Quaternary breccia, often containing jumbled bones. Thus the name: the bone breccias. Here is one from the Pula "dinosaur track sites" containing the bones of a small horse (photo credit: B.Krzic):






 The close up: Outlined with red are front legs hooves (heart shape) and the skull.


The age of these "breccia horses" of the genus Equus is late Villafranchian to ? Holsteinian (possibly even late Pleistocene).
 
A paper:

Paläontologische Zeitschrift
December 1992, Volume 66, Issue 3-4, pp 369-385
Mirko Malez, Ann Forsten,Jadranka Lenardic