Key Features of Torvosaurus

The natural conclusion to yesterday's art by Davide Bonadonna

Torvosaurus differs from many other North American and European giants in a number of ways. Obviously the European material from Portugal did not undergo the adaptations witnessed in other European dinosaurs that are the results of insular dwarfism (as so recently discussed both last week and in the discussion of Balar bondoc). In North America the material gathered in Colorado and elsewhere, including potential material from Wyoming and Utah, was slightly smaller than or equal to the largest predators found in the west as contemporaries of Torvosaurus; "savage lizard" sounds a little more fearsome than "different lizard" (Allosaurus) but a little less fearsome than "lizard-eating master" (Saurophaganax) and so is nestled in both size and fantastic nature of name nicely in the middle of its contemporaries. Physically there were also many differences between this megalosaurid and its allosaurid contemporaries preserved in the fossil remains; no good "mummifications" exist for all of these contemporaries to my knowledge that would allow for extensive soft anatomy comparison.

Skeleton at the North American Museum of Ancient Life (Thanksgiving Point, Lehi, UT), photo courtesy of user Ninjatacoshell

The teeth of Torvosaurus are impressive, though not completely definitive of the genus or the family. Some of the skeletal markers that make it different from its contemporaries include the length of its ilia and pubic bones as well as lack of ornamentations on specific areas of the skull such as the lacrimal ridges (a bone of the "face" near the antorbital fenestra and nasal bones). Allosaurus, especially in the past few years, has been depicted with rather prominent nasal, orbital, and lacrimal ridges of bone and soft tissue, particularly the latter. Megalosaurids, such as Torvosaurus, show no evidence of ornamentation along these bones and it is assumed that the lack of ornamentation in the bone was a precursor for a lack of ornamentation of soft tissue in those areas. The skulls of the two dinosaurs are also different in overall size and length with Torvosaurus possessing a longer nasal bone that creates more solid bone area between the nares and antorbital fenstra than is found in the more rounded off and shortened muzzle of Allosaurus. Fore and hindlimbs of Torvosaurus are somewhat like those of Allosaurus; both have three clawed hands as well as feet. The claws of Torvosaurus appear slightly larger and stronger, but I have not seen a documented study to support this at the current time.

From Colorado to Portugal

©Davide Bonadonna

First and foremost, many thanks to my sister Anna for taking over last week while I was in the field helping a colleague trap mice and avoid rattlesnakes. If you did not notice a difference, that means she did a fantastic job, right? Kudos to the author and artist to be!

This week I have a monster of a dinosaur for us. Obviously, in sticking with my typical rotation, we are going to look at a predator this week, and not just any predator, but one that has been discovered in both Colorado and Portugal in varying stages of life including as an egg and is a fearsome predator of the late Jurassic. Larger than most of its contemporaries, including most Allosaurus individuals, Torvosaurus tanneri was a forced to be reckoned with. Three clawed hands and massive jaws were supported by a robust torso and well muscled and strong legs in this megalosaur. This "savage lizard" was between 30 and 26ft (9 and 11m) long and probably weighed nearly 2.2 tons (2 metric tons). The Portuguese specimen is the largest discovered meaning that the eastern counterparts of the Colorado specimens were either slightly larger overall or that the Colorado specimen may be a younger individual than the Portugal specimen. The Portuguese Torvosaurus rivals T. rex's skull and is much larger than any other Jurassic age predator while the Colorado material is slightly smaller than Allosaurus/Saurophaganax and another animal known as Edmarka (which may be synonymous with Torvosaurus).

What A Strange Little Dinosaur

Zalmoxes lacks a lot of popular culture references we have seen on the internet. It did feature in some news stories back when it was renamed and a little afterwards. Zalmoxes has warranted enough looks that it has been detailed by the Natural Museum of History in London on a fact page also. However, as we have seen, it did not manage to ascend to documentary dinosaur status as yet and has also not been portrayed as a model or toy dinosaur to my knowledge at this date. Zalmoxes has made its name in World of Warcraft as an item, as have many other dinosaurs. Apparently it is represented by a robe that players can acquire on a once previously mentioned landscape within the game. Sadly, that is where that popularity ends for Zalmoxes. A greater number of dwarfed dinosaurs from Transylvania are being discovered these days and that will pique interest in someone soon enough I am sure to warrant the creation of a documentary or toys or something else that gets the name out there more.

The Island Life

Brian Cooley's Zalmoxes sculpture

Depending on the specific species, the size of the Zalmoxes differs greatly. Z. shqiperorum was the largest species and could grow up to four and a half meters long. However, the smallest, Z. robustus, would only grow up to three meters long. Z. robustus was thought to be so much smaller than the Z. shqiperorum because of insular dwarfism. Insular dwarfism was the theory that large animals evolved by decreasing in size when the food sources are limited due to lack of land mass. Since Zalmoxes lived on islands, they were said to evolve over generations by decreasing in size so they would not need to eat as much plant matter. This allowed for Zalmoxes to continue to populate and also have lots of available food.

Papers of the Zalmoxes

Zalmoxes, the poor unfortunate "unusual Euornithopod" has had some osteological and phylogenetic study done on it. That 2003 study by Weishampel, Jianu, Csiki, and Norman was the landmark paper that renamed Rhabdodon robustus as Zalmoxes robustus and identified a second species as Zalmoxes shqiperorum. Thankfully Dr. Weishampel is nice enough to host his own papers so we can read the entire paper, all 59 pages, of the in depth anatomical description of Zalmoxes and how it differs, and is thus officially distanced, from Rhabdodon. The matrices and characters are included, which is always nice to have, so that the systematists amongst us can really look at the characters that were analyzed. The osteology of newer specimens has also been discussed, this time only for Z. shqiperorum though. The 2009 paper discusses a new fossil site in Transylvania, Romania and the specimens of Z. shqiperorum that had been unearthed from that location.

No One in Motion

Zalmoxes does not appear in motion pictures, short or full length, animated or computer graphics. There is an alphabet video that mentions Zalmoxes in the Z slot of the alphabet; there really are not too many dinosaur choices in the Z slots of the alphabet. Dinosaur Train's A to Z episode does not use Zalmoxes, sadly for us; I know everyone wants to see the Dinosaur Train song again and again. Zalmoxes, and the other Transylvanian island dinosaurs that have been discovered, truly do deserve their own documentary. Some day this will certainly happen. It has not so far and thus I have nothing to share in terms of video today, unfortunately.

Children and Dwarf Dinosaurs

Science for Kids has a pretty good fact page going for Zalmoxes. It is a bit short, but it gets the important information out there quick and in an easily readable way. Additionally, I found a pretty sweet puzzle site that is any age friendly. You can make the pieces any size you want from a 12x12 puzzle down to a 2x2 puzzle. That means you, or your child/nephew/niece/sibling, can customize the puzzle to fit yours, or their, skill abilities. Pretty nifty if you ask me. Seeing as how you can create your own puzzles on that site, be prepared for more Sunday kid friendly posts with dinosaur puzzles! This will help a lot for dinosaurs that are not as popular. Also, when you are done with your puzzles and reading your facts, here are a couple of coloring pages worth all kinds of time and fun to color and detail!

Rakes for Hands, Giant Heads

Cast in Brussels, photo by Ghedo

Some inconceivable reason caused the curators of the Museum of Natural History in Brussels to take a rather nice cast of the rhabdodontid dinosaur Zalmoxes and give it rakes for hands and feet. A great deal of the skeleton of this genus, spread over two Romanian species and, potentially, a third Austrian species, is well known, but this does not include fore and hind feet. Despite this, enough is known of the rhabdodontid iguanodonts that a reasonably educated guess could have been easily made for the casting of this skeleton. Regardless, we can get a sense of the overall dimensions and lay out of the skeleton of these species by looking at this cast. The scapulae are rather slender and long, which is pretty interesting and the skull is a triangle of sturdy thick bones with a fairly nice dental battery found inside the mouth. The skull truly sets Zalmoxes apart from many other dinosaurs and as such, we will definitely be looking at that in a moment.

Attributed to Anky-Man

The skull, if not the skeleton, of Zalmoxes, is quite robust. Muscles would have create a fairly good bite force, but in all likelihood the main manner of getting energy out of its food would have been through a lot of grinding of the dental battery. The mouth, and it is always up in the air when discussing this, may have been enclosed in a flap of cheek to help in chewing plant matter. A cheek is instrumental in holding vegetation in the mouth during mastication; without a cheek your food would mostly end up falling out onto your favorite t-shirt unless you held it in there with your hands. The skull of Zalmoxes is very iguanodontid in overall shape and form, but it is small and, given the size, more robust than seems necessary for this dinosaur. Perhaps, if insular dwarfism is responsible for the small stature of this dinosaur, the head was the last part of the body to begin to "shrink" through successive adaptations. However, maybe there was a significant bonus to possessing a large tough cranium in Zalmoxes environment.

©Vlad Codrea (via MSNBC)

Those big heads must have been used for something, right? Then again, they could have been mistakes or slow to adapt to the island life. Zalmoxes is thought to have "suffered" from something called progenesis. The main thing to understand about progenesis is that it is a developmental acceleration of life. A rhabdodont that took five years to achieve maturity and then lived another 30 years or so may have been perfectly normal but the same animal, under the effects of progenesis, may have matured in a year or less and only lived between five and 10 years total. Progenesis is not a disease so much as it is an adaptive reaction to an external stimulus that, over generations, forces animals to breed faster in order to sustain population and pass on genetic information. Insular lives may have caused just such a thing to occur and the adaptations of dwarfism as well as progenesis together may well have been enough to cause those sturdy crania of Zalmoxes to stand out as much as they do if they did not do so on account of a beneficial adaptation for large crania. Perhaps we will have a definitive answer to this query soon.

Dinosaurs that Start with the Letter Z

©Mariana Ruiz Villareal

Two species of dinosaur, one originally in the genus Mochlodon, belong in a Z genus. Those dinosaurs are Zalmoxes robustus and Zalmoxes shqiperorum (do not ask me how to pronounce that please). The generic name comes from the Dacian city of Zalmoxis. For my human history deficient friends, Dacia was a region in the Carpathian mountains, now part of quite a few countries including Romania and the Ukraine, between the Tisa and Danube rivers inhabited by a people called the Dacians by the Romans who practiced a religion called Zamolxism, which got its name from Zalmoxis the chief god of the religion who had a city named after him. Essentially, then, the name Zalmoxes, is a tribute to a Dacian city and god. The specific epithets, Z. robustus and Z. shqiperorum, carry the meanings "robust" as in the robust build of the skeleton and the Albanian word for Albania (Shqiperia) respectively. The dinosaurs we are looking at are small, squat rhabdodontid iguanodonts; they were somewhere between a buff looking hypsilophodont with a thick powerful jaw and a basal iguanodont. The two species have different adult sizes with Z. robustus measuring in at about 7 to 10ft (2 to 3m) and Z. shqiperorum at 13 to 15ft (4 to 4.5m). The size was of Z. robustus was attributed to the wonderful spectacle of insular dwarfism, which we have discussed previously in this blog.

Happy to Visit

Juravenator, while not the most popular dinosaur, has made its presence known in video games, which is something of a marvel these days. I have never personally heard of this game until today, somehow, but it looks as though it would be pretty nifty and dinosaur-iffic. The only drawback I really see is that it looks a little slow paced, but that could just be the way it was being played. Juravenator also appears in a few dinosaur books, such as the Princeton Field Guide by Paul, where fishing is indicated as part of diet (we never mentioned that this week!), and Feathered Dinosaurs: The Origin of Birds by John Long. A very nifty illustration of Juravenator is also present in Martyniuk's Field Guide to Mesozoic Birds and Other Winged Dinosaurs; though there is not an entry on Juravenator itself, this wonderful piece appears in the opening chapter of text. I do not think I have mentioned that book much, but as a bird and dinosaur lover I have to say I really enjoy the "field guide-ness" of the book and that his style of illustration is pretty refreshing compared to many other illustrators out there that seem to emulate each other here and there.

Toes in Sand

The toes of Juravenator are dinosaur toes for certain. Are they adapted to a life on a coastal shore and treading in the sand and mud? We cannot tell for certain because we do not have clear imprints of the integument surrounding those toes. The claws at the ends of the toes, however, are not exactly beachwear that would facilitate long walks or even short jaunts and sprints. The tail is where the feather/scale argument is centered. The integument traces preserved here indicate scale presence as well as the presence of some protofeather-like traces. The overall indications of the posterior half of the body of Juravenator indicate that it was not extremely well adapted to a sandy shore and that it was at the basal end of the feather scale if it indeed possessed any true feathering. Due to the lower adaptivity to the sand it probably visited the sand, but did not spend the majority of its time exactly at the shoreline.

Nothing for Free

©Nobu Tamura

There is never a free article when you want it. In fact, free articles are rare unless they are old enough that they have made it into the world of free press (i.e. out of copyright and online) or JSTOR happens to have the article available and that journal's contents have been purchased by someone or some institution that one has access to. Technically this article on Juravenator's phylogenetic relationships is free to me and many others, but only because we have paid the dues to be a part of the SVP. Abstracts for the description of the anatomy of Juravenator and the naming of the species and a more cursory look at the anatomy including interesting integument structures are available as well. The in depth anatomy paper is probably quite interesting for anyone with an anatomical leaning or preference. I am going to try to get a hold of it somehow, because I like reading about anatomy.

Comprehensive Views

This video shows a rather comprehensive series of shots of the preserved skeleton and also shows some illustrations. Some of the labels are a little odd and there is no explanation at all of what each part of the animal is, does, or why it is important that it has been preserved. Additionally, some elements are zoomed in on without any mention of anatomical position, making their purpose, without the details of purpose written out, cryptic at best for the uninformed. Why start with such a video? Because it is extensive in what it looks at on the preserved specimen of Juravenator and it is not a cartoon or computer graphic but focused shots of the actual skeleton. It is also being highlighted today because there are no other videos, not even tribute videos.

Juravenator, Kid Sized Dinosaur

The image at the top of the Natural History Museum of London's fact page makes for a fairly good coloring page, though it is quite small and blowing it up may blur some of the lines. Not much else has been created solely for children in regards to Juravenator. That is sad news. The fact about this dinosaur is that it is small and though well known from the specimen that has been recovered from the ground, is not very popular. A life size replica would be little more than a toy, so most model companies that make dinosaurs have not made a replica of the little dinosaur, which rules out statues. Toy manufacturers may simply not be aware of the small animal or may have decided that there was no demand for such an unrecognized dinosaur in their toy market. Regardless of the reasons, Juravenator makes up a very tiny amount of child-friendly knowledge of dinosaurs.

What Does a Tiny Hunter Look Like?

As I mentioned yesterday, Juravenator is thought to be a juvenile specimen, indicating that the miniscule size of the specimen is not the full adult size of the animal. I still happen to think that this a very sad thing because a teeny dinosaur like this would be pretty fantastic. At barely half a meter from tip to tail having a Juravenator for a pet would be a pretty good reality (and given the exotic nature of some pets a high probability scenario) if they were still alive and the juvenile turned out to be an adult. The problem with not having an adult of course is that it may turn out that this juvenile might be freshly hatched and only 1/5 or maybe even 1/10 the size of an adult, perhaps less even. What would something this size, regardless of adult or juvenile status, living on the coast of the Tethys Ocean eat? One obvious answer, for any carnivorous or omnivorous animal living on a shoreline is fish, whether hunted or scavenged. Scavenging for a coastal predator means nearly anything that washes up in a state that is edible becomes fair game for dinner and competition amongst the predators that find it. Additionally, other scavengers, mammals, young from many other types of animals (or their own kind perhaps), and perhaps even vegetation may have been on the menu as well.

The skull of Juravenator, though a little crushed, preserved a lateral view of the mouth quite well. All indications by the teeth concerning diet point to a pretty voracious little carnivore. The teeth are fairly thin front to back and a fair number of the larger teeth curve backwards, a design that we know aids in retention of prey items as well as in slicing material. Those teeth that are not curved backwards appear to point straight down and have nearly the same front to back thickness as those that are curved backwards. These different teeth may be due to preservational issues or they may have been used in a different manner; however, preservational bias seems to be the more accurate answer as some of these differently shaped teeth also appear to be slightly damaged. If, however, they were used for a different purpose, it appears that that purpose would be to anchor the jaw, as though for gripping, rather than slicing or holding down onto live prey. That sort of mechanism would only be really useful to a predator that was using its hands or feet to tear at meat and more than likely it would rather use hands and feet together; this is why deformation of the teeth in preservation seems a more likely explanation.

The Mountains of Jura

The Jura Mountains of Germany yielded one of the smallest dinosaurs we know. Thought to be a juvenile due to its miniscule size, Juravenator starki, is a 75 cm long coelurosaurian theropod dating to approximately 150-152 million years ago. Remember that naming new species from juveniles is not generally advised considering the growth series and life histories of many dinosaurs have altered many species' positions as well as names in years past. However, sometimes all we have to go on originally is a juvenile specimen and sometimes it is different enough to justify a new species. Additionally, this could just be a very small dinosaur; without other specimens at this time it is harder to assert the age of the animal. I kind of hope it is a full grown animal because it would be like the lap dog of dinosaurs (though I do not like lapdogs a lapdog dinosaur would be fantastic). Jurassic Bavaria, along with the rest of the European continent, was a much more tropical environment with many more miles of coastline than are now present on the continent; mostly due to the fact that many of the landmasses that would become Europe were underwater and a lot of islands dotted the Tethys Ocean. Juravenator was a coastal predator and scavenger. Covered in very primitive feather-like structures and extensively scaled (evidence for these assertions are found on impressions around the tail), Juravenator appears to exhibit a very basal position in terms of dinosaur feathering witnessed in other compsognathids. Juravenator is also thought to be a nocturnal animal, as detailed in comparisons of the sclerotic rings to those of living birds have shown.

In the Know

Paralititan is famous friends. So it would appear anyhow. Paralititan shows up as Spore creations, toys, video game bits, in documentaries (a pretty good synopsis here of the Planet Dinosaur episode), and in many other artistic ventures (one of my favorites: Paleo-King's illustration). Some of the best Paralititan videos are shown below:

Paralititan as a Spore creature. Well done overall, however the butt is way up in the air, which is a rather strange orientation any dinosaur, though a hadrosaur walking as a quadruped approaches this level of butt-in-air.

A small short made with video game models and some clever steering of the camera. Not bad given what was available to the creator of this short video. It does get a little choppy at times.

Kafka Distractions

You know you want a hug too.

When I went to search for things to talk about this morning here I got distracted by Kafka's doodle on Google. I thought I should share that I love that doodle. Anyhow, what about Paralititan's minimalist remains is exciting? The most stunning bit of anatomy is, of course, the rather significant humerus that has been discovered. The humerus was about 5.54 feet tall; if you know me personally imagine the "upper arm" of a dinosaur that is the same height as me. Assuming nearly equal distance of the lower forelimb and throwing in a healthy estimate of height (top to bottom) of the relaxed foot, we are looking at a dinosaur that possibly had a shoulder that was nearing 13 feet in height; those estimations are my own and not highly scientific so please do not quote me in an argument with your friends over dinosaur size. The other thing that is most interesting about Paralititan is that, as much as people the past twenty years and more have been fighting the popular image of dinosaurs in swamps with more and more evidence, this is a dinosaur that lived in mangrove territory. Mangroves are a fairly swampy, or at least estuarine, group of trees. That makes Paralititan a swampy dinosaur. At least for times during its life anyhow.

The Mangrove Swamp

Stromer collected a lot of vertebrates in the early part of the 20th century in North Africa's Bahariya Formation. Included in these totals were fish and turtles, plesiosaurs, Spinosaurus, Carcharodontosaurus, Bahariyasaurus, Aegyptosaurus, and a number of crocodiles. Sadly, it is popularly known that Stromer's collections were mostly destroyed in Munich during World War II. That probably made comparison between Aegyptosaurus and the newly discovered Paralititan difficult if not impossible; the extent of the casts and any other remains of Aegyptosaurus are unknown to myself and the description of Paralititan does not expressly describe Aegyptosaurus in comparison. That said, the describing article (hosted at the Carnegie Museum of Natural History website) announcing Paralititan is rather short at 3 total pages including references and images (one page of text without images approximately), and does not include the character states coded for on the first page. Paralititan, regardless, is missing a large number of characters, but the remains also contain a respectable amount of characters as well; enough to assuredly assign Paralititan to the titanosaurids. National Geographic, which has written many stories pertaining to African dinosaurs within the last 15 years or so, mentioned Paralititan briefly in a 2007 article as well. The neatest part of that issue is the poster I got from it that is now hanging in my school office. The image of Paralititan from that poster is pictured here.

Paralititan Planet

I suppose we cannot really say they owned the planet, though they did take a pretty big space in it, considering that they were rather enormous dinosaurs. Paralititan is a somewhat minor character in Planet Dinosaur's episode "New Giants". Due to this and the fact that the BBC regulates what can be seen in America online (certain countries are denied the ability to view clips on the BBC's website), it is pretty hard to find a quality clip from the show to share here today. There are some substandard clips (recorded from the television, not recorded on television) out there as well as tribute videos. There are wireframe models out there available for purchase that are shown in videos, but they are not that great overall. If you happen to catch any re-airings of Planet Dinosaur or live in a country where clips are allowed by the BBC check that out, if not, you may just have to make due with the second hand recording of Paralititan to see it on video.