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Biplanes and Other Papers

June 2, 2015, 6:36 pm
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Sankar Chatterjee, and R. Jack Templin 
PNAS 2007;104:1576-1580
Microraptor has become a magnet for attention in a variety of ways in the scholarly article realm. There have been some regular articles, such as those describing specimens and reconstructions and descriptions of the feathering of this magnificent dino-bird. There are also inquiries into the flight capabilities of Microraptor. These include simple flight models and complex, confusing models of Microraptor in terms of the modern mechanical marvels known as biplanes. The graphic from that paper is amazing, as we can see here. As a counterpoint to much of the discussion about flight, there is also an article that states that flattened Microraptors do not lend themselves well to flight models. That is a pretty good argument, it has to be acknowledged.

Caption for the image from the paper: Wing planform of Microraptor.(A–D) Different possible hindlimb postures during flight. (A) Hindlimb backwardly directed as in modern birds. (B–D) Biplane configuration. (B)Hindlimb backwardly sloping position. (C) Hindlimb forwardly sloping in predatory strike position. (D) Hindlimb in z-fashion with a body silhouette showing the animal in lateral view with an upwardly tilted tail for pitch control. (E) Cross-section of the tibia–fibula showing a streamlining and stretching effect of the cylindrical tibia by adding feathers caudally. (F)Cylindrical structure offers maximum resistance to the airstream as the airflow behind it becomes broken up into eddies, creating turbulence. (G) Filling the spaces in a cylindrical structure in front and behind improves streamlining, as in the case of the feathered tibia of raptors. (H) Pouncing posture of a raptor, Falco. (I) A typical staggered biplane Stearman for comparison with Microraptor; in biplane aircraft of the 1920s, there was a large additional drag of wires, struts, etc. between the two wings, which eventually made the biplane obsolete except for a niche application; such drag-induced structures were absent in Microraptor. (J) Life reconstruction of M. gui(IVPP V13352) in dorsal view showing the morphology and distribution of hindlimb feathers (Left) and orientation of the hindlimb (Right) during gliding, based on Fig. 1 A; proximal feathers on the humerus and femur are inferred (data are from ref. 12). (Scale bar, 5 cm.)
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Small Thieves

June 3, 2015, 8:38 pm
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While some thought, or think, that Microraptor was only capable of gliding flight, we saw some papers yesterday that thought it was capable of powered flight. Regardless of the actual flight abilities of the dinosaur, we know that it had feathers and that those feathers carried black pigmentation. The fossilized melanosomes sound like the subject of speculation and science fiction, but they were found, analyzed, and determined to resemble those cells associated with the color black. The cells were found in the long pennacious feathers of the dinosaur, those capable of flight. The feathers were, of course, the key trait regarding the ability to fly in these small dinosaurs. all four limbs and the tail were feathered, and that feathering constructed what appears to have been a sturdy airfoil like those found in extant birds.
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Popular Everywhere, Maybe Even China

June 4, 2015, 6:58 pm
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The discoveries of multiple specimens of Microraptor gui are the result of combined AMNH and Chinese cooperation. Some of the fossils were originally smuggled out of China and the various states of preservation even created a nomenclature issue at one point, with the genus Cryptovolans being designated for one of those fossils. Other names given to the fossils include Microraptor zhaoianus and Archaeoraptor liaoningensis. As this was a topic of much debate and contention, we have stuck with the accepted name, Microraptor gui, and not mentioned the various other names. The fossils have been popular all over though, despite their nomenclatural discontinuity. The dino-bird has appeared on the BBC and in countless other documentaries and networks over the years. It has also graced many, many pages in books. It is not much of a surprise that it has been modded into video games, and even included in the Dino D-Day game that is available on Steam. That game is well worth the paltry sum they ask for it!
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Dwarf Iguanodons

June 4, 2015, 10:06 pm
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The fluted tooth miniature Iguanodon known as Rhabdodon is a genus with two recognized species, R. priscus Matheron 1869 and R. septimanicusBuffetaut & Le Loeuff, 1991. The animals were discovered in Cretaceous soils of Europe; Spain, France, and Romania more specifically. The French material has not been assigned to either species as yet, but with two species, Rhabdodon is in a minority of dinosaur genera in that it contains multiple species. The lack of lumping of taxa in paleontology means that the French material may belong to either species but may be assigned to a third, if that trend continues. If it does not, then it will not, obviously. Either way, Rhabdodon is a "simple"Iguanodon but is a very interesting dinosaur regardless.
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Downy 'don

June 6, 2015, 1:26 pm
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©Tom Parker
It has become apparent that the discovery of feathers on more basal dinosauriformes has convinced more and more illustrators that all dinosaurs need feathering. This is, of course, not entirely universally true, but it is also not completely without merit. Regardless, the interpretation of Rhabdodon with feathers is unique, but interesting. The idea that it had little chicken legs is a little odd and the wing-like forelimbs is pretty sad looking in general. All told, Rhabdodon looks like a big downy chick with a dinosaur head in this interpretation. Quality work, a little unorthodox, but a good quality interpretation.
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Rabid Rhabdodon

June 7, 2015, 10:34 am
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Strangely Rhabdodon is actually a rather popular dinosaur with kids. The dinosaur shows up in the Dinosaur Train alphabet song and on the website. It also appears on some kid friendly websites other than Dinosaur Train like About and Prehistoric Wildlife.

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Rhabdodon on the Move

June 8, 2015, 4:46 am
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I have shared the Dinosaur Planet episode Pod's Travels about five times now because it has a lot of different insular species that we have discussed. I even shared it once on an Iguanodon post because Rhabdodon is, in effect, an insular version of Iguanodon. I can share it again in here and will do so. The animals are referred to simply as Iguanodon but the show notes mention that they are based on skeletons of Rhabdodon. I have never personally understood why television does that sort of thing, but that is how it is. Unfortunately, that is about where the references to Rhabdodon on television or in movies dies out, unless you have the ability to watch old episodes of Dinosaur Train. There is a Rhabdodon character named Reba on an episode or two, but none of the clips are stand alone bits from the show or available online (without the sanction of PBS) otherwise.
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In French, s'il vous plaît...

June 9, 2015, 4:45 am
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The first responses to my search for papers are in French. That is not a problem in and of itself, unless you know absolutely zero French. The fact that there are French language papers published in regards to the material discovered in France and potentially attributed to a species of Rhabdodon (remember some French material was questionably assigned to a third species) is perfectly logical. The paper on Spanish remains is not in Spanish though, so it makes one wonder if the French authors are just being selfish in their publishing (that is just a joke, you know!). Some of the most intriguing information can be found in the paper about the braincase of Rhabdodon, if you like papers about the head and brain.
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Cretaceous Bovine Anatomy

June 10, 2015, 7:51 pm
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Rhabdodon and other members of the Iguanodon family have rather basic and schematic anatomy. One iguanodontid looks quite a bit like the next member of the family and so on down the line, for the most part. That is, of course, an ugly blanket statement when anatomy and morphology are considered. Rhabdodon was a smaller member of the tree and, as such, the anatomy of the animal was much like that of its larger cousins, but scaled down a bit. The lack of soft tissues makes it difficult to determine if any of the missing organ systems were different or if they were, like the skeleton, a slightly different but mostly scaled down version of its cousins.

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Teeth of Rhabdodon

June 11, 2015, 8:44 pm
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Teeth in question
The fluted teeth that give the dinosaur Rhabdodon its name are hard to find a good image of online. There are photos and images in the papers about the dinosaur, but these are not readily available without some screen captures and cropping. The teeth and the body of the dinosaur are actually kind of strange in their hypsilophodontid-esque morphology. Despite these morphological similarities the phylogenetic positioning of Rhabdodon still remains solidly in the iguanodontid family. Regardless, the fluted tooth name refers to the shape of the tooth.
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The Attraction of Dinosaurs

June 12, 2015, 5:22 am
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Now that Jurassic World is out in theaters, we really should stop and ask ourselves, what is it that the public finds so endearing about dinosaurs? The size of dinosaurs is a clear option, as most people enjoy the site of animals that are far larger than seems practical for life. Elephants and whales are clear examples of this type of animal. Dinosaurs are even bigger (the ones people love the most anyway), maybe making that one of the most important factors that there is in determining our love of dinosaurs. I think it is more important for the second more obvious idea that governs our love of dinosaurs to exist. That idea is that we love dinosaurs not because of their sizes, but because they are mysterious animals that we see in snippets of time. Those short time captures are usually death events, but occasionally the death event itself is so rapid it actually turns out to be a portrait of the life history of the dinosaur. These are invaluable to us as the fossils in the death throes, maybe even more important. When we are truly lucky those life portraits are not only well preserved nesting dinosaurs or fighting dinosaurs, but they can even end up being mummified to the point that their soft tissues are still present in some form of quality.

In respect to one of the major players of the movie, one of the larger fossil animal genera, and a member of the "ruling reptiles of the sea", we shall discuss the mighty Mosasaurus this week. Oddly enough, Mosasaurus has not made it onto the list here yet, though other members of its family certainly have. Currently six species are recognized in the genus with Mosasaurus hoffmannii Mantell 1829 residing in the slot of type material. The genus has been around slightly longer and was assigned originally by Conybeare in 1822 with his description of the "Meuse River lizard". Despite the name, which is location based, the aquatic reptiles were ocean loving animals, and their size was appropriate for large predators of the Mesozoic oceans.
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No Single Image

June 13, 2015, 7:25 pm
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Today I think it would be wildly inappropriate to post a single image of a single species of Mosasaurus. There are a lot of different interpretations of Mosasaurus and these can vary depending on the species that one is looking at as well. Fortunately, there is a nearly catch-all place to look at Western Interior Seaway Mosasaurus species in illustrated form. The work of the late Dan Varner has been collected by Mike Everhart and hosted on his site for a long time, and Varner focused a great deal on the animals found in North America, but that list is extensive in its own right and is not necessarily speciated from those species found in Europe and Asia. In a few images he placed some unique and interesting traits like forked tongues, but they are peculiar enough in their speculation (and phylogenetic relationships) that they actually do not appear absurd. In working on marine reptiles in the not so distant past I frequently saw these images, and I have grown quite fond of them. I encourage everyone to take the time to explore and appreciate them.
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Kids at the Pool

June 14, 2015, 5:47 pm
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First of all, regardless of the feelings anyone may have for or against the latest movie, this t-shirt design related to the movie is fantastic:
Best design I have seen this weekend, for anything, bar none. Anyhow, there are links everywhere for Mosasaurus. Enchanted Learning has some information and fun about Mosasaurus and even Dinosaur Train has a lot of videos and information about Mosasaurus. The state of North Dakota is behind Mosasaurus entirely, endorsing it and disseminating an awful lot of information to the masses about this very popular fossil from their state. There is plenty to read about in these few links, but if there needs to be more, the links abound just typing Mosasaurus into Google.
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Manic Mosasaur Monday

June 15, 2015, 8:17 pm
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I got a little sidetracked last night and forgot to hit enter on the post. Here is the post for Monday though.

The majority of Mosasaurus videos on the internet right now are steeped in so much Jurassic World glitter and shininess that the reptile has lost a lot of his educational links in the muddling. There are plenty out there though. The reason for all of the pre-JW links is as obvious as the reptile: it is definitely one definition of charismatic megafauna in the fossil record. We are discussing a large aquatic reptile, a world often forgotten in the dinosaur craziness of the Mesozoic that, when it does surface, is thanks to more news about enormous ferocious predators more likely than not. However, the pre-JW links of Mosasaurus related material were not all educational and news stories themselves. There was an episode of the BBC show Primeval (the translation makes it a little more disturbing) which has a very unlikely attack; humans are not worth an animal that large beaching itself I am quite sure. There are more than enough documentaries also, from the sensational Discovery series Mega Beasts (we can cut them some slack because they did reach out to people that know their mosasaurs) to the serial killer portrayal in the Reign of the Dinosaurs series (also Discovery, a bit overly dramatic).
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All There is to Know

June 16, 2015, 5:19 am
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Anyone looking for a one stop paper on anatomy of Mosasaurus can visit this JSTOR page and take the rest of the day off. The paper is thorough and well written, and covers a wide swath of the anatomy of Mosasaurus hoffmannii, making it an indispensable reference for the mosasaur enthusiast. There are also descriptions of fossils throughout the history of our discoveries of mosasaur specimens including Mosasaurus beaugei Arambourg, 1952 and Mosasaurus conodon Cope 1881 (admittedly the second paper is more of a review of the taxon). Technically minded individuals may appreciate studies of dental microstructure in mosasaurs or maybe even rare earth element analysis  that determines where and when an animal was alive. The last paper reminds me of the summer I did inorganic chemistry research. I enjoyed some parts of that more than others.
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Reptiles in the Ocean

June 17, 2015, 5:27 am
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The ocean going reptiles of the Mesozoic were not a small faction of the population of those oceans at that time. Since different groups were considered the ruling reptiles of the ocean at different times it can be safely assumed that the various groups of pelagic reptiles were the apex predators of their day. The families that held those titles became increasing larger to usurp the title from previous groups but, because of the needs of aquatic locomotion, did not appear to be strangely exaggerated in shape or form (think of the reactions of most people the first time they see the arms of Tyrannosaurus or Carnotaurus). From ichthyosaurs to plesiosaurs there was not an enormous swing in terms of what family was considered the apex predator group, though both had higher members in specific niches. Mosasaurs, on the other hand, evolved forms that were capable of being not only the apex predators in a wide variety of niches, but also dominated the previous acme of icthyosaur and plesiosaur domination. In fact, they ate quite a few of the largest ichthyosaurs and plesiosaurs. There were copious reasons for this changing of the guard.

1. The teeth of Mosasaurus species were conical and bone crushing. Some members of the family ate hard shelled organisms with very different teeth, but Mosasaurus species were purveyors of the larger, squishier, bodies of the ocean and preferred to crack down only on the shells of ammonites and sea turtles when looking for crunchy food items. These were, of course, much softer than giant clams, though a case could be made for the toughness of ammonite shells as extremely hard bodied. Either way, the conical teeth of mosasaurs were excellent in their presumably strong jaws at breaking into the softer shelled swimming organisms and certainly the soft bodies of plesiosaurs and whatever remaining ichthyosaurs that were in the oceans of the Cretaceous.

2. Swimming with paddles worked for the somewhat slower plesiosaurs; smaller necked plesiosaurs tended to be speedsters while their longer necked cousins took a more relaxed approach at life. Mosasaurus species, however, were built for speed all over. Their streamlined crocodile-esque shape is not a coincidence. That shape of body has been toyed with in many lines including mosasaurs and crocodiles and has proven effective for speed and maneuverability in aquatic landscapes. The evolution of paddles to stabilize and turn the body and a very powerful tail capable of motoring at high speed make for a deadly combination for slower animals and the ability to ambush, assuming mosasaurs followed the typical marine camouflage patterns of predators, would make them deadly for swifter prey as well, though with a lower success rate probably.

©Nobu Tamura
There are other obvious, and less obvious reasons for their domination of the oceans, but these two are highly visible to all and rather obvious to infer, therefore lending themselves to quick observations. I know there are a lot of people that can add to these reasons, and their input is definitely welcome in the comments!
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Swimming with Class

June 18, 2015, 6:05 pm
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Teylers Museum, Haarlem
Mosasaurus has, as expected, had a big draw as a fossil, on the blog, and in the movies. This is very apparent in Jurassic World, of course, but other documentaries and such that are almost movie length would count as well. The video game presence is also noteworthy, as is the literature (non-scientific) in which one or another species of Mosasaurus is discussed or pictured. These are, to be certain, most usually lumped together under the generic name, but it makes little matter in the long run. The point of knowing that these animals are known in children's literature, popular literature, and other venues like video games, is understanding that they are charismatic enough that they are considered worthy of study as well as awe inspiring and fantastic by many including the general public. Scientists kind of have to have interest from someone or their research grinds to a halt rather quickly, unfortunately. That sort of interest has led to the massive displays of mosasaur remains in museums worldwide, like that of the type specimen in Haarlem and others. They are wonderful to look upon also, so they are worth seeking out.
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Another Omission

June 19, 2015, 7:09 am
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©Matt Matyniuk
Somehow, through a calculated decision at the time I discussed flying reptiles three years ago, I omitted Pteranodon. Due to the focus on getting correct information out on Jurassic World dinosaurs and other creatures, we really need to talk about that ubiquitous flying reptile and king of the skies. Probably the most prominent member of the genus is Pteranodon longiceps Marsh 1876 which was originally recovered in the western Kansas Smoky Hill Chalk deposits that were laid down during the existence of the Western Interior Seaway. Pterosaurs in general have long been associated with water because their best preservation has been associated with shorelines or the middles of what was once ocean and Pteranodon is not an exception.
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Heinrich's Pterosaur

June 20, 2015, 7:18 pm
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©Heinrich Harder
Some times the classics are almost correct and do not need a great deal of revamping. Beautiful as the newest illustrations of Pteranodon appear some times, the original depictions of Heinrich Harder are actually quite spot on for the presently accepted morphologies of Pteranodon. The wings, for instance, are fairly appropriate, though debates probably still range over the placement of the patagium between the legs and tail. The small head crest would most likely indicate that these individuals, if they are Pteranodon longiceps, females. The larger head crests would indicate males, as Pteranodon longiceps is considered to be sexually dimorphic with males having larger bodies overall, including the crests on the head. Not seeing different body sizes in these animals we can only make an educated guess based on that shorter crest. Harder, however, may have been illustrating these Pteranodon based only on the fragmentary evidence of the fossils that had and have been collected throughout the American West.
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Father Pteranodon

June 21, 2015, 3:00 pm
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Pterosaurs are well loved by all ages and groups. That, as it tends to do, lends itself to wonderful amounts of links and coloring sheets and all kinds of educational resource. The most obvious, at the moment, is definitely Dinosaur Train. The show is based on a family of Pteranodon. Visiting your local PBS website, or not so local if you are from outside of the U.S., will furnish you with more than enough educational links to discuss with your family today. Coloring sheets abound as well on sites like Enchanted Learning. The most important thing on this rainy (here) Father's Day (also here) is that everyone learns and people get to enjoy their days and their families.
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