No Chicken Wings

Anomalopteryx_didiformus 
J. Erxleben. M.&N. Hanhart lithograph

All genera of Moa and all species within those genera present with entirely absent pectoral girdles and forelimbs. The hindlimbs more than made up for the lack of forelimb, which is good considering the birds were all completely flightless. Not having to worry about a tail or a pair of waving wings allowed Moas to run with their enormous legs. They may not have had a fast sprint, but they certainly had robust musculature attaching to the legs. The femur is approximately half the length of the tibiotarsus. Considering that the majority of the forward sweep of bird's legs tend to be through extension of the knee joint a shorter femur does not necessarily provide a final indication of speed. The longer tibiotarsus, however, was very robust and must have possessed strong muscles that would have been able to power the legs off the ground and through their arc of movement. Moas were most likely better equipped for running across the open lands of New Zealand rather than the forests. The center of gravity would have been oriented right around the area between the knees of the bird and directly above the enormous feet. Any forelimbs would have also destroyed that center and brought the bird just enough further forward bending that any running would have been difficult if not impossible, making for a very clumsy giant.

Finding the Moa

There are probably more papers about Moas than I could ever read. However, quality papers appear to be lacking online. There are interesting papers that are available though. There are some ichnofossil papers describing trackways, which are interesting and fun to read. The idea that the trackways, more like gametrails, are still apparent in the photographs the author shows is both amazing and somewhat unbelievable. After nearly 600 years of absence it is certainly conceivable that the trails could have disappeared, but being gametrails they were probably used by "man and beast alike" even after the disappearance of the Moa. Other papers explore the genetics problem of attempting to sequence amino acids in a selection of Moa. That is not an area of expertise for me, but I would recommend reading it to see what the authors attempted in their experiments. One of my favorite subjects, though, is addressed today. The last paper to be shared today is about sexual dimorphism. As with many birds, the females were significantly larger than the males. The authors discovered this and lumped three species into a single species using nuclear data. That is all the spoilers you will get for this paper, I encourage you to read it!

Monster Moa

As stated yesterday, there are plenty of videos of Moa related fun online. In one slightly older video, a professor associated with the NHM of London (I think) discusses the Moa. There was even a deleted scene in Peter Jackson's 2005 King Kong remake. I personally do not think it looks anything like what a Moa would look like. The Monsters We Met, a BBC series that incorporated Walking With imagery, also featured Moas, but if you visited the BBC page uesterday you know that. There is also this rather unique Moa fact film:

Moa Facts

When you type "Moa Facts" into a search engine you get returns on the Mall of America. Did not think about that. You have to be a little more specific than that. However, when you are, you can get some interesting results. Not only did I get Enchanted Learning fact sheets and coloring pages (typical quality of illustration though), but I also got facts about Moa from the Kiwi Conservation Club. Their page is a little bit more colorful and fun looking. The most professional site (in terms of renown) is the BBC site about Moas. Considering it has videos it may make it onto tomorrow's list as well, but that is a discussion for tomorrow!

Compare Away

Kiwi, Ostrich, and Dinornis

As recently extinct animals, Moa skeletons are in fairly adequate supply. There are burial grounds where the Maori tossed Moa skeletons in different places around New Zealand. These burial grounds have allowed for preservation and in some cases some fossilization of the remains; fossils can also be found around the islands where Moas died prior to Maori colonization of the islands. This allows us to reconstruct the skeletons of many individuals. That then allows us to compare Moas to other birds, in this case, living ratites that are the sisters to the Dinornithes. The egg may or may not be an actual fossil (I have not found any authentic sources one way or the other in regard to this and hesitate to make any assumptions), but the comparison between the eggs of Moa and other large ratite eggs is somewhat startling. Overall we can see here that the skeletons of Ostrich and Moa are quite similar, but the sternum of the Moa is very weak and almost appears to lack substance altogether. Part of the reason for this is the reduced nature of the forelimb. The wings of Moa were actually completely absent from all species, making the pectoral girdle vestigial at best and completely useless to the bird in terms of function. Lacking wings and the musculature needed to power wings, the bones eventually became evolutionarily defunct. These were obviously reduced beyond the point of vestigial structures and the powerful sternum of was also reduced. Those familiar with Hesperornithiformes are familiar with the absent pectoral girdle architecture of those birds and may be able to draw parallels with Moas.

Rule Breaker

John van Voorst

I think I may be breaking some sort of unwritten rule this week with the animal I want to discuss. While certainly extinct, the extinction event that we are concerned with this week is only approximately 600 years ago. Possibly the last near-remnants of the great "Terrorbird" times, the original Polynesian colonizers of New Zealand managed to hunt all 6 genera of Dinornithes or Moa to extinction within about 200 years of encountering the giant birds. The reason I consider these recently, geologically speaking, avians worthy of being discussed in a paleontology minded sphere is because they were definitely worthy of their name of Dinosaur Birds. Not only were they enormous, but Moas were also completely wingless and in control of the landscape because their only natural predators were eagles native to the islands. Hold in there dinosaur fans, they will be back soon. Actually, remember that dinosaurs gave rise to birds, so we are still talking about dinosaurs here with our Moas!

Fast Week

Piatnitzkysaurus is actually a somewhat well known dinosaur. It has been made into a working model in Spore and featured in Dinosaur King multiple times. The appearances are in the card game rather than the television show, but numerous cards have been created for the series of games. The information page maintained by fans notes that the dinosaur has always been shown as possessing four fingers while the known skeletons possess only three digits. The ultimate in so-so reconstruction is actually a dinosaur postage stamp sheet from the Maldives. It does show Piatnitzkysaurus fishing though, which is interesting.

That Body

The body of Piatnitzkysaurus, we know, is very allosauroid in its general shape. As such, and given key characteristics of the skeleton, it was at one point labelled as a basal carnosaur. Piatnitzkysaurus was probably never considered to be an allosauroid entirely on account of the fact that it was an Argentinian dinosaur and, correct me if I have forgotten, there are no prominent Argentinian allosauroids. However, subsequent studies on megalosauroids by Benton have determined that Piatnitzkysaurus was in fact a megalosaur. It is definitely not an abelisauroid or a tyrannosauroid theropod. What does everyone think?

Canada and Argentina

In 1979 Piatnitzkysaurus was described by Jose  Bonaparte. The dinosaur was described in an article in Science and can be found, with reading permissions, online. That is a rarity for articles, but it is very nice for us to get to read the original paper. Over time Piatnitzkysaurus has not been highly publicized, meaning that it has probably not been very highly studied either. If it has, it has not made its way into prominent publications. One study that did, though, was on the braincase of the dinosaur. This is a subject that is always of interest as we can learn an awful lot about the shape and size of the brain. This allows us to make educated hypotheses about the abilities of the dinosaur that may have been present when the animal was alive.

Speed, Not Facts

Let us take a day to simply watch some drawing. There are no documentaries and no short news stories, so drawings are the best we can get today!

Factoids

Piatnitzkysaurus is a little bare on the internet. In general the sites that do discuss Piatnitzkysaurus are well done sites that address the facts, present them, and are pretty aesthetically pleasing. I picked out a top three and, in no particular order, here they are.
NHM of London: Presented as a very short list of facts, the illustration that is used is very outdated, but the concise nature of it is great.
About: Performing as we expect, the description and listed facts of About are wonderful, as usual for teaching the most important facts to dinosaur enthusiasts that do not know Piatnitzkysaurus.
Cool Dino Facts: An even more concise list of facts. Use this site as a support site in discussing the dinosaur at best.

Not Allosaurus

Piatnitzkysaurus has been compared to Allosaurus at least once that has been noted. There are some similarities between the two dinosaurs, however they are not identical or close to identical by any means. Both dinosaurs were agile in appearance and actual morphology. This means that both dinosaurs had the ability to run down their prey. Additionally, the forelimbs were longer than many later theropods and strong enough to adequately grapple with larger prey items. These could have included, for Piatnitzkysaurus, iguanodontids and sauropods. The teeth of Piatnitzkysaurus are average for a theropod of this size; they are robust and would have made good puncturing devices, but grappling prey and running it down was probably the main hunting tactic for this medium sized carnivore. Considering its size it may have, as Allosaurus is thought to have, hunted the largest sauropod prey in small impromptu packs organized during migration seasons. This, of course, is just an unsubstantiated hypothesis however.

Born in Russia

The Russian born paleontologist and geologist Alejandro Mateievich Piatnitzky has been immortalized by being the namesake of an Argentinian dinosaur, Piatnitzkysaurus floresi. Named in 1979 (with remains collected in 1977, 1982, and 1983) by Jose Bonaparte, this Middle Jurassic dinosaur was a midsized carnivore that highly resembled Allosaurus. The resemblance was noted nearly twenty years ago, but it has not run into any kind potential lumping situations. We will have to look at this comparison during this week as we look at the story of the dinosaur and its history.

©Nobu Tamura

Selling Itself

Brontosaurus sells itself. As Apatosaurus it also sold itself, but the idea of Brontosaurus has obviously brought back the dinosaur itself for a ridiculously large audience. Probably the best way of showing how Brontosaurus has impacted popular culture is to show the original dinosaur movie:

Why Is It Different?

The list of differences between Apatosaurus and Brontosaurus are actually alarmingly small. That is the reason, of course, that the two were made synonymous in 1903. Those differences that have been discussed as differing enough to cause the second separation of the taxa are still just as slight. The single character that the PeerJ flow chart makes a large deal out of is the shape of the bifurcation of the neural spines on the vertebrae. The Brontosaurus neural spines appear to have a sharper angle of bifurcation and a shorter vertebra as a whole. The Apatosaurus vertebrae are less acute in their neural spine angles and appear larger and flatter as a result. The heads of the two dinosaurs are believed to be extremely similar, perhaps identical. Their pelves have no significant differences either when viewed as a whole; smaller differences may exist on the individual bones of the pelvis of course. Those that read the paper yesterday are aware of the evidence that was used to describe the split between the two, so going in depth here should not be necessary.

The Only Paper That Matters

There are an absolute plethora of papers about Brontosaurus, Apatosaurus, and why they are and are not the same dinosaurs. The only paper that I am going to link and recommend to everyone today is the most recent paper that was published last week. The PeerJ article is available free online and has the ability for the reader to leave comments on different parts of the article. Enjoy the read, and definitely discuss below.

Factfinding Journalism Wins Today

DNews did a great job of addressing all of the media frenzy of last week around Brontosaurus. My job here is done.

Not Lost

For the most part kids never actually lost Brontosaurus. Many of the sources for dinosaur information still listed Brontosaurus as a valid name or, at the very most listed it in parentheses as Apatosaurus (Brontosaurus). That is why the majority of sites that we can reference today mention or are titled Apatosaurus (with the exception of the misspelled "Apotosaurus" of KidsDigDinos). The New Zealand hosted Science Kids hosts a good encyclopedia style page and Animals for kids parallels and maybe even outdoes this. The black and white search of images turns up a plethora of coloring sheets that can be used to make your own thunder lizard.

Thundering Lizards

Above, awesomeness. Below, Charles Knight's interpretation of what was at the time (1897) Brontosaurus excelsus. Six years later the dinosaur was lumped together with Apatosaurus and became A. excelsus. The Knight version is very similar to the Zallinger mural piece and they probably borrowed from one another extensively and spoke to the same paleontologists. The interpretations of pretty much all sauropods in the late 19th and early 20th centuries depicted highly aquatic swamp dwelling creatures that dragged their tails whenever they left the water. Acting like large reptilian hippopotami, the herbivores were thought to be slow and pondering in and out of the water. This anachronistic version of Brontosaurus has not been completely erased from the popular psyche, but it is becoming less widespread. This is both good and bad because the history of the science and art is very interesting but it does portray the animal incorrectly.

©Charles R. Knight

The Much Avoided

Not for the sake of jumping on the wagon of dinosaur fame, but this week we are definitely going to discuss Brontosaurus excelsus. Long considered to be a junior synonym, but unique in ways that left doubt lingering since the 1903 lumping of Apatosaurus and Brontosaurus, an extensive recent publication has separated the herd once more. Had the Brontosaurus/Apatosaurus confusion not existed to begin with Brontosaurus would have been discussed here ages ago. However, discussing the "thunder lizard" now is appropriate given the attention that it has collected in the media. Now considered to be more derived than Apatosaurus, the enormous Brontosaurus was quite a beast at 22 m (72 ft) long and nearly 15 tons.

Marsh's Brontosaurus

Popularity of A Popular Taxa

It is not hard to say and show that Dire Wolves were, and continue to be, popular. The most popular outlets for Dire Wolves during my lifetime have been National Geographic (previously shown), collectible card games (of which Magic the Gathering's art was my favorite), and Game of Thrones. There were a lot of card games that hit on the idea of using the Dire Wolf as a character or some kind of card. The illustration for Magic was great though. Apparently it was also the title of a Grateful Dead song, but I had no previous knowledge of that. The fact that there was that much more than I knew or had been exposed to during all of the searches that I have done this week is not at all amazing given the expansive knowledge of Dire Wolves that is out there.

Elder Wolves

©Robert Bruce Horsfall

Old illustrations of Dire Wolves, unlike many other fossil animals, are very uniform in their anatomical/morphological aspects. The reason for that is reliant on a pair of items: 1) wolves in general have not changed so much that the morphology of a wolf is fundamentally different from what it was when Dire Wolves roamed the Americas, and 2) the sheer number of Dire Wolf remains is enormous. The latter is probably more important to the scientific community as it means that the number of animals available for study is nearly astronomical, to be a little hyperbolic. This point was not lost on paleontologists or the artists like Charles Knight and Robert Horsfall that created stunning murals and single pieces for museums and collectors in the early days of paleoartistry. These wolves, stuck in the tar pits of La Brea, are depicted in a somewhat classic natural pose for carnivores as they defend a kill. Slightly more ferocious looking than many other Dire Wolves that have been illustrated, this pair is quite charismatic.

Papers Everywhere

There are plenty of papers on Dire Wolves. Part of the reason most definitely lies in the fact that the Dire Wolf is, in fact, a wolf, and therefore a very charismatic animal in the hearts and minds of many people. Any dog, in fact, would count, but a giant wolf is not just a charismatic animal, but charismatic megafauna. The number of studies of Dire Wolves because of this has been exponential and explored areas as diverse as craniofacial morphology and reproductive behaviors. Probably the most abundant studies concern the tar pits at La Brea, records of populations, and body mass estimates. The reason for the records and discussion of specimens recovered from the tar pits can be seen in this wall of Canis dirus skulls that were recovered from La Brea (i.e. sheer numbers!).

Pyry Matikainen (pmatikainen) Licensed under CC-By-SA-2.5

Wild Documentaries

One of my favorite National Geographic specials today. There are a number of videos that discuss or feature Dire Wolves, but the Nat Geo special is well worth the watch and should be done before it is potentially removed from the web.

Sunday, Busy Day

I have written three posts today to come up to speed to today. I'm going to let this Love Nature video tell you some things about Dire Wolves:

Origin Story

©Sergio De la Rosa Martinez

The origins of Dire Wolves seemed to have become somewhat confused at some point. There has been discussion in the past as to where these wolves came from and how they became as large, as a population and individually, in North America. As with many animals in North America it appears that that the origins lie in a movement over the Bering land bridge into North America from Asia during the Quarternary period. The animal that actually made the journey was a somewhat different canid known as Canis armbrusteri. During its fanning out into different packs throughout the central plains of North America the animals began to differentiate appreciably and eventually C. armbrusteri disappeared as a recognizable species and was effectively replaced by C. dirus which arose from these new adaptations and speciation events. The Dire Wolf packs moved into the South American continent as they continued to differentiate from C. armbrusteri and two subspecies (C. nehringi and C. dirus) developed, but are not officially recognized as such because they are considered to be genetically identical. Two subspecies have been named in North America though. Canis dirus dirus is recognized as being larger and populating the lands east of the Rocky Mountains while the west coast and lands were populated by the smaller C. dirus guildayi. It is most interesting to note that the extant Gray (C. lupus) and Red (C. rufus) wolves are of Eurasian origin, more recently than the Dire Wolf. These two species survived through the extinction which claimed the Dire Wolf in part because they were smaller and more agile, allowing them to expand their prey selection whereas the Dire Wolf was built more for wrestling, as a pack, the larger mammoths and other megafauna that died out at the end of the Pleistocene.

Critters Fantastic

©Charles R. Knight

One of the most fearsome of all the mammalian carnivores of the Pleistocene was the pack hunting Dire Wolf (Canis dirus). Lately this blog has been on a bit of a mammalian run, and there is nothing wrong with that, but this is the first mammalian carnivore that we have had the pleasure to discuss. Canis dirus is not the direct ancestor of extant canids but most likely acted in a very similar manner with a pack mentality that extant wolves (C. lupus) and some populations of coyotes (C. latrans) exhibit. The genetic lineages of these giant canids, separated from their relatives somewhat recently, were also related, but very distantly, to the foxes of the world. It is pretty amazing to think that a wolf the size of a Dire Wolf ever existed or that it could have been even minutely related to foxes, some of which are under 10lbs currently. The skeletal size of Dire Wolves appears to be similar to Gray Wolves, but estimations of mass based on the robusticity of their bones state that Dire Wolves may have weighed up to 25% more than their sister taxa; this would mean a weight range between 50 and 79 kg (110 and 174 lbs). It is of importance to note that the largest extant Gray Wolves can weigh as much as 54 kg (120 lbs), though these are typically relegated to the "untamed wilderness" of northern North America and Asia. Possibly due to the fact that man and wolf coexisted, they have been portrayed as evil vicious and enormous wolves that have an insatiable lust for violence and carnage. Possessing a bite and teeth that appear to have been well adapted to breaking the skin of even the megafauna of their day (mammoths and mastodons), there may well be reason that the human herd memory of these large canids is filled with outright terror.

Busy Days

Iknow that i do not have to convince my readers that Sivatherium is an awesome beast. It has appeared in books, papers, video games (Zoo Tycoon 2) and many other popular ventures. I am glad it takes no convincing as I am out of town at a mini conference in Texas. I had dinner last night with a cool small group and tonite with a lot of awesome people. It's a little sad it was so hard to hear our talk because of the band playing though. Also, I have a lot coming out of my shell to do at these things still

No Jokes

Cave art attributed to the Sahara

According to the The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals Sivatherium has been represented in rock paintings in the Sahara desert. Knowing that human cultures existed at the same time as Sivatherium this is a statement that could definitely hold water. The key to examining that claim, however, is knowing what the paintings looked like or if they still exist. There are two images, both equally terrible images, that have circulated that are supposedly from the Sahara and India that represent rock paintings of Sivatherium.The paintings appear to possess some giraffid qualities that could certainly represent the animal of interest. However, the one attributed to Indian civilization also appears to be easily representative of almost any four-legged animal that one might find on a farm let alone in the wild. The large horns in the Indian rock painting could be meant as ears and overall the picture looks very similar to a donkey with an elongate body. Elongated bodies would not be as important in portraying Sivatherium as elongate necks would be; however, artistic interpretation or the inabilities of the artist may just be showing up in this crude art form.

Cave art attributed to India

The Sahara attributed image is much more consistent with our interpretation of a giraffid animal and appears, vaguely, to have some horn-like appendage at the top of the small head. Small heads on large necks, though, are not exactly representative of the morphological state of Sivatherium; large heads on elongate, but short and thick necks are more accurate. The painting also has a long body, but not quite as long in appearance as the piece from India and in better proportions than the one from India. It is possible that Saharan cave painters were simply better at animal representation than their Indian counterparts, or that the species of Sivatherium in India was morphologically different enough that the image appears distorted but is not. Whatever the reason, someone that professionally interprets cave paintings once associated the paintings with Sivatherium and that interpretation will always exist somewhere in the world.