Silly Saurs

Asilisaurus kongwe is not actually a funny name. It comes from Swahili and means "Ancestor lizard." As a Middle Triassic Dinosauriform, Asilisaurus is in a very primitive or basal position on the phylogenetic tree. It is so far down the tree, in fact, that it appears to be very near the pterosaur and dinosaur branchings on the family tree. One of the most specific labels we can assign to Asilisaurus is actually Avemetatarsalia, the group that does include both pterosaurs and dinosaurs. This is going to be an interesting look at the bottom of the tree, a phylogenetic placement that is not often examined.

I Thought You Were Likable

Regardless of how one feels about mammals and apes, we really owe a lot to the likes of Proconsul and its descendants. We are, after all, distantly related to these early apes. They may not have toys and plush animals like dinosaurs do, but they are just as important tot he history of life on this planet, and we know so very little about them, despite the treasure trove of knowledge we have concerning the genus. There are PBS specials that discuss this very important ape. There are also books and many scholarly papers in reputable journals. However, the general public, for a variety of reasons, knows very little about Proconsul and other early apes. There needs to be a lot more PBS viewership, in my opinion.

African Forest Dwelling Apes

Twenty-three million years ago, give or take, the transitional ape Proconsul appeared in the fossil record as a definitive genus with four recognized species. As with all apes, these were tail-less creatures that scurried about the trees with grasping hands and feet (paws on all four limbs to be more accurate); admittedly some extant apes are not as happy in the trees as they are on the ground despite having the ability, if needed, to at the very least get into a tree's branches. The skeletal remains that have been recovered and displayed show these grasping abilities quite well in the articulated hands and wrists. The skeleton also appears to end somewhat abruptly where the tail would be on a monkey (at the end of the vertebral column, that is). This could be a feature of a line that had only recently truly lost their monkey tail characters, or it could just be how that particular ape genus was shaped. Book end genera would help to accurately describe that morphological trait, but so far I have not found any studies that explain or describe the species that may have preceded or descended from Proconsul.

Proconsul nyanzae

Assertive Statements

The question of whether or not Proconsul possessed a tail has been definitively answered before. One of the most assertive statements about that tail came from Carol Ward in 1991. There are more fantastic papers about slightly more interesting topics in the history of Proconsul (not that Dr. Ward did not have an interesting paper). These topics include discussions about the skull, locomotion (also Ward), and even a Proconsul centered systematic revision. Systematics are a difficult topic, but it is papers like that that will answer the monkey or ape question concerning our furry little primate. Rather than giving the punchline for them, I recommend that reading paper be the first priority of the concerned, but uninformed, citizen scientist.

Thanks PBS!

PBS did a nice job "introducing" (many years later of course) Proconsul to the world. Therefore, let us allow Holly Dunsworth to discuss Proconsul in far more eloquent terms than I have been able to to this point. That is the point of move Mondays anyway.

Kids Monkey Around

Monkey around, or ape around, whichever is appropriate in this case, either way Proconsul has a great many links for kids and adults alike. The links feature sites like Prehistoric Wildlife and About. They do not, however, feature too many child specific games, coloring sheets, or games. Actually, the image below from the French version of Wikipedia could be used as a coloring sheet in a pinch. There could be a lot of fun involving simians and kids and fun activities, but there are not, at this time. Proconsul was is not an unimportant fossil, so it should have even more information than it does online, but obviously this is not the case.

Monkey or Ape

©Nobu Tamura

Once in the past I wondered what made monkeys and apes different. The quick answer one usually hears is that a monkey has a tail while an ape does not. Looking at restorations and fossils of the four species in the genus Proconsul, then, would lead to the quick assertion that Proconsul was indeed an ape. However, being ancestral to apes and sitting hypothetically, and possibly firmly, at the base of that tree, where do we draw the line between the first ape and the "last" monkey on its way to apes? Is Proconsul a sophisticated monkey lacking a tail or is it a basal ape holding onto some monkey characteristics? I honestly hope to get a friend of mine to write that up for us this week, really quickly if possible, but I will do it on Tuesday and Wednesday if that is not possible; I probably need to read as many papers about the little simian as anyone else here that is curious. For now, though, enjoy this fairly standard restoration of Proconsul that is, as usual for the artist, very well thought out and put together and conveys a real sense of how the animal must have looked in action.

Not A Chimp

Primates of the Miocene epoch pre-date known chimpanzees, and at least one species was closely related to the extant chimpanzee. The genus level is a little more confident in terms of knowing the ancestor of chimps. The genus most closely related, as far as we can tell so far, is Proconsul. An arboreal Miocene primate, Proconsul, was discovered in eastern Kenya and described in 1933 by Arthur Hopwood. I have a lot to learn for this week, so I have to cut today short. It turns out I know very little about primates and will probably have to consult with an anthropologist I know. Either way, primates are important members of the fossil record, and this is a fitting first ever primate for our purposes.

Guérin Nicolas

Toy Time

Some days you find your Deinotherium in a video game (also available on Facebook) and sometimes you find it in the toy aisle. I prefer vintage art, like the Harder piece shown earlier this week and this piece featuring a small herd of Deinotherium (or is it Deinotheria?). The fact that a lot of these vintage pieces are not online for free is sad, except when they are modern and made to look vintage. The inclusion of Deinotherium in the Walking With series only further introduced them to an already captive audience, and honestly probably got a few more people thinking about them more seriously.

Trunks?

Dmitry Bogdanov

How do we know that Deinotherium has a trunk like other elephantine animals? The quick answer is that Deinotherium is a proboscid and therefore inferences into soft tissue anatomy that are missing will be based on extant animal models that are readily available. Those, in this instance, are the elephants that roam the African and Asian continents. Additionally, of course, soft tissue leaves visible attachment scars on the fossilized material that has been discovered around the globe. The tissue that attaches to the skull that indicates the presence of a trunk is unknown, to me, but is apparently evident enough that it does indeed lead to inferences for a trunk (probably in addition to the inferences that are made by the fact that the animal is related to extant organisms that tend to have trunks).

The Paper Elephant

There are so many articles and published studies on Deinotherium that it is almost ridiculous how much information is simply floating around out on the internet. These animals are charismatic because they are large mammalian herbivores and they look like elephants. They are also charismatic because we know so much about them. This kind of circle can go on forever honestly. The more we get to liking some animals the more we study them and the more we like them. In the case of Deinotherium that is honestly a truth. The teeth have, of course, been studied quite frequently. The entire, or partial, skeleton has been studied as well many different times. What is most intriguing about Deinotherium studies, however, is the global involvement of the people studying these animals. They have been studied from remains in Kenya, Greece, Bulgaria, Portugal, Saudi Arabia, and many other localities. The geographic and temporal diversity of the animal is quite astounding.

Hunting Elephants

In one of the weirdest Facebook games I have seen to date, one can hunt prehistoric animals including Deinotherium. This has little to do with videos except that I found a video capture someone made of the game where they were hunting Deinotherium. I am sure most modern big game hunters would love to go after dinosaurs if they were given the chance. That is an interesting proposition, were it viable. The real videos, the documentaries, are from the Walking With Prehistoric Beasts series from the BBC. Their Deinotherium is a very robust creature and quite wonderful to watch in action. You can see it in the clip below where it shows its hatred of primates. I do not know if they did something to irritate the gentle giant.

Links Not For Kids

Deinotherium was a well known beast. Partly because of the oddity of its mandible, and partly because of its elephantine appearance, it has been seen many times over on the internet. The links that lead to Deinotherium information online are all fairly uniform in the long run; dense writings, middle of the road amounts of information, and even fact sheets. Strangely, despite all of the wonderful knowledge about Deinotherium and number of links online, none of these sources appear to be oriented toward the younger generation completely. In fact, there are no dedicated videos aimed toward children and there are also no actual coloring sheets available to hand out today either.

Sizes and Species

The species of Deinotherium are compared here. The size of the genus is generally similar to the size of the modern African Elephant, but a little bit taller. The tusk situation is obviously radically different for the two enormous mammals, but the general plan of the tusks is the same in both. Tusks are extremely large dental growths in both taxa. The tusks of Deinotherium, as can be seen here, extend ventrally, and eventually caudally, from the mandible. The recurved and tapering tusks are a key identifying feature of the animal. They may have been used to dig roots or as defensive tools. They could also have been used to pull down branches. There may never be a definitive answer to that question, but they are quite interesting and unique features to look at.

A New Week

First of all, I admit I omitted yesterday's entry. In part it was because I do not have a good writing schedule these days; I really need to get back into having a set time to sit and write every day so I am going to schedule that in. Additionally, there was nothing to really say about the past week's animal in terms of popularity. The crocodile just is not popular for a variety of reasons, chief amongst those being that it has simply escaped the popular culture knowledge base for a good while now.

This week, however, we have a semi-popular herbivorous fossil animal to discuss. There have been a number of elephant and elephantine animals discussed here over the years, however, we have managed to avoid one of the stranger proboscids (the order Proboscidae includes the African and Asian elephants) that has walked about on the planet. Deinotherium is a genus of near-elephants that possessed downwardly curving tusks situated in a medial rostral position of the mandible. Ranging over Africa and Eurasia, Deinotherium species were important figures in many landscapes and, as we can see now, were very curious looking animals. Even older illustrations, like Heinrich Harder's happy proboscid below, are accurate in respect to their strange mandibles. Hopefully we can find a good explanation of this morphology this week!

Warming Your Face

As stated many times over, Aegisuchus, the "shield croc", was probably using the boss on its head to do a number of small tasks. One was, almost undoubtedly, as an outpost for many of the vessels of the head as they crossed in and out of the temporal fenestrae and warmed and cooled the brain and head, as in the medium sized 'gator shown below. Thermoregulation by conduction in the blood vessels is not unheard of in crocodiles and, in fact, is also seen in other extant taxa such as birds. Birds, for those that did not know, use a system of heat shunting in their legs, in particular, to keep warmer blood nearer their cores during the winter months and to shed the heat during the summer. Additionally, going back to our crocodile, the boss may have served as a signalling device. Having vasculature in the area could have allowed the crocodile to divert blood to and from it in a way that would allow the colors of the skin to change and signal to conspecifics as well as other animals that a threat or mate was near. Both uses are realistic and interesting and can be somewhat observed in their extant relatives as they use similar tactics to wake up in the morning.

Credit: Me, from about 3 feet away. Florida IS good for something! (I kid!)

Single Papers

The only paper that exists for Aegisuchus is the paper that described the new animal. That paper includes highly detailed figures that show the fossil anatomy and the negative space anatomy of the fossil. That negative space is occupied by the brain of the big old crocodile. Often the endocasts of fossil animals are hypothetical at best but this endocast of the brain is almost (there is a tiny amount of hypothetical space) entirely enclosed and anatomically correct. Have a look at it for yourself.

Let Him Explain

As I have said, I have personally talked about this animal many times over now to large audiences. However, I am not anywhere near as good at talking about it as Dr. Holliday, so we can let him explain it, as he has to me many times in the last year, in his own words:

Kids Love the Croc

Aegisuchus is an animal that has not made a big impact in the world of child related website links. It has made one solid impact though, on Prehistoric Wildlife, but is in a more literature heavy context on that site. That said, it is important to note that it has become one of the most favored fossil animals that goes on tour with us to museums and other outreach events.

Flat Heads

Holotype fossil. Left, photograph, Right, interpretive illustration. A, dorsal view; B, left lateral view; C, rostral view; D, caudal view. Scale bar equals 1 cm. Abbreviations: adt, adductor tubercle; bo, basioccipital; boss, integumentary boss; bs, basisphenoid; cc, cranial cavity; chr, choanal recess; cp, cultriform process; dtf dorsotemporal fenestra; dtfo, dorsotemporal fossa; eam, external auditory meatus; ept, epipterygoid; fm, foramen magnum; fr, frontal; fso, supraorbital nerve foramen; fX-XI, foramen for cranial nerves X and XI; fV_2,3, maxillomandibular foramen; gV₁, ophthalmic groove; ls, laterosphenoid; mec, middle ear cavity; oc, occipital condyle; pap, paroccipital process; po, postorbital; pop, postorbital process; ppr, post-occipital protuberance; qu, quadrate; sq, squamosal; sup, supraoccipital; vf, vascular fossa; vg, vascular groove.

The holotype material of Aegisuchus is a little difficult to interpret the first time one looks at it with no direction or insight into the fossil. However, with even a fragmentary picture of the head of an alligator one should be able to notice the nearly symmetrical foramina on the top of the head. After noticing that it is fairly straightforward. The frontals can be seen extending rostrally from the foramina giving a solid interpretation of rostral and caudal areas of the fossil. Additionally, when viewed caudally the occipital condyle is easily seen; in the highly detailed 3D printed model of the fossil the condyle is unmistakeable whereas it may be lost a little in the photos above.  The foramen magnum is also easily seen and, thanks to the wonders of science (i.e. CT scanning and digital modelling), an endocast of the brain is also available. The printed model of the brain amazes people when we tell them what it is.

Lungfish for Dinner

Typically I can say one or two things from my personal experiences with any given fossil animal that appears here. This week I can, hopefully, offer up more than that because I have handled the 3D model and described the animal to a lot of people during outreach events and traveling museum showcases. The animal of the week is a lesser known crocodyliform with a flat head named Aegisuchus witmeri. Known from a partial braincase and the skull roof, the croc was being stored in the Royal Ontario Museum until was noticed by Casey Holliday who, working with Nicholas Gardner, described and named the animal. The chief restorative illustration of the animal was created by Dr. Holliday's then PhD student, Henry P. Tsai (who has graduated and gone on to a position at Brown). The morphology that is known about this croc is very interesting and will be discussed in length during this week.

Illustration by Henry P. Tsai for Holliday and Gardner, 2012

New Paper Trails

Not specifically about Sinornithomimus, a new paper about lever mechanics in ornithomimids was released today. The study only reinforces the fact that ornithomimids as a group continue to be popular. Sinornithomimus is not at all the same as Ornithomimus but the similarities of the two are very apparent in the majority of the skeleton, with notable differences that allow for differentiation of the genera. The dinosaur itself does not appear in a lot of books, toys, or other media however. The skeletons of the known individuals appear very much like those shown below.

Walking Differences

What is it that makes Sinornithomimus different from all of the other ornithomimid theropods? These dinosaurs, generally speaking, are very similar overall. They all appear to be cursorial and omnivorous animals that lived in some sort of herd structure. In that respect they are not much different from hadrosaurs, except that they probably had a more insect based diet. The herding mentality of the dinosaur is what really led to the marvel of the dinosaur. Fossil beds of mass graves tend to have that effect for some reason. The fact that Sinornithomimus was discovered intertwined in a mass of bodies is not new to paleontology by any means, this happens somewhat often, considering the rarity of fossils to begin with. The herds in China and Mongolia of ornithomimids like Sinornithomimus may have looked something like this, though, and it is interesting to imagine it.

Gregarious Dinosaurs

The original description of Sinornithomimus concluded that the dinosaur was a gregarious species that was very happy and at home with the idea of being in a herd. This was decided on based on the fact that the original material was a slab consisting of 8 individuals intertwined plus various other finds in the same area. The material was described by Kobayashi and Lu in a 2003 paper in Acta Paleontologica Polonica. Very little other scholarly work has been done on the dinosaur, however, it has been used to discuss similar genera and species within the ornithomimid group. The similarity of these kinds of animals to one another is interesting and it is therefore strange that a massive comparison piece has not been attempted as yet, but I have no doubts that there will be at some point.

Mass Graves

Mass fossil beds, or mass graves to be more depressing, are a rare but very exciting coincidence in paleontology. The best large yield quarries have interesting stories and pasts and they are very well known usually. The site at which the massed Sinornithomimus skeletons were recovered is a well known site in China and has a bit of a story. Rather than attempt to retell a retold story, however, here is a short video detailing the story for you.

Sinornithomimus Links

Links to share for Sinornithomimus are few and far between. In fact, the only two that are relevant for helping young ones learn more about dinosaurs are a news release from National Geographic (http://news.nationalgeographic.com/news/2009/03/090315-young-dinosaur-herd-china-missions.html) in 2009 and the About (http://dinosaurs.about.com/od/carnivorousdinosaurs/p/Sinornithomimus.htm) page dedicated to the dinosaur. Given that this animal is like a lot of ornithomimids, that is not amazing and really should not be a surprise. Either way, enjoy the links that are out there and share them with someone you love today!

Mimic That Bird

Paleoart in the modern era is all feathered out. There is a variety of reasons for that, not the least of which is the discovery of more and more fossils containing feathers of various kinds and therefore different states of feather evolution. Feather development and feather evolution are very interesting topics. They are topics that one might easily associate with a Chinese bird mimic, understandably. The fact that these omnivorous (herbivore and insectivore most likely) beaked runners were covered in feathers is, in this image, taken as a sure thing. The extent of feathers may have been less if we assume that Sinornithomimus was in fact a highly cursorial animal. The ability to run fast and with high maneuvaribility would likely require less downy fluffiness. However, it is hard to say if this may have been the condition during the nesting season or if this was the feathering condition and Sinornithomimus was actually more of a pacer than a sprinter. There are exceptions to the rule of course, like Cassowaries.

By Michael B.H.

Chinese Ostriches

In the realm of dinosaurs that you may or may not need to have as species are the ornithomimids. What we mean by that is that there are so many species spread over the world in this family that are highly similar in morphology that it leads one to wonder if the multitude of species that have been named within the family are really distinct species. The geographically isolated members of the family probably constitute legitimate speciation, such as the "Chinese bird mimic" Sinornithomimus dongi. As happens often in Chinese paleontology of late, the dinosaur was named after its 1997 finder, a man named Dong Zhiming.  The animal was described in 2003 by Yoshitsugu Kobayashi and Lu Jungchang and the holotype, a subadult individual within a larger herd group, is known as IVP-V11797-10. It is not a glamorous name for a running machine with a lot of leg power, but it will do for the time being at least; probably longer since paleontologists give their fossils names much earlier in the recovery process it appears.

Type specimen skull: Yoshitsugu Kobayashi and Jun-Chang Lü

 

Done Deal

It has become quite apparent that Procompsognathus is not a very popular dinosaur, partly because it has been replaced in most spheres by animals that closely resemble it like Compsognathus and even Coelophysis. This means that in dinosaur books, video games, and the toy market. In part that is because of the more complex name, but not entirely.

Gracile, No Doubt

The gracile body of Procompsognathus was very much like that of Compsognathus in terms of its slender, theropod body. The long tail, as with any other theropods, was as much for balance when reaching, standing, and otherwise moving but stationary as it was for stabilization during running and maneuvering. The head was small (ish) and the teeth were built for crunching smaller insects, lizards, and mammals. Given that the legs look as though they were for running and the hands for grasping, the dinosaur was probably built to burst in speed for short distances and snatch prey on the run.