STL Science Center

STL Science Center

23 September 2018

Pseudosuchian Archosaurs

Rather than spend today telling the intrepid readers (and viewers of videos) what a pseudosuchian is and is not, I present to you today videos that show, describe, and discuss Revueltosaurus.The genus Revueltosaurus consists of three recognized species: R. callenderi Hunt, 1989 type; R. olseni Hunt and Lucas, 1994; R. hunti Heckert, 2002. The first video comes from Petrified Forest and the National Park Service. It describes the finds at the park and where some of those bones come from on the skull of this crocodile relative. The second video features NMMNH Chief Scientist Spencer Lucas talking about what exactly Revueltosaurus is and is not, in a very short manner of time (the clip lasts approximately 90 seconds).


17 September 2018

Daspletosaurus Appears on Television

Daspletosaurus was an interesting tyrannosaurid for a number of reasons. One of the reasons that has been explored was that Daspletosaurus was contemporaneous with another tyrannosaurid, Gorgosaurus libratus. The BBC show Planet Dinosaur was willing to imagine the world in which these two gargantuan dinosaurs lived, how Daspletosaurus may have hunted its prey, and how Daspletosaurus and Gorgosaurus may have interacted. The clip below only shows Daspletosaurus hunting and fighting with a Centrosaurus however.

16 September 2018

Facts and Cartoons

I'm A Dinosaur did a little bit less packing in of the facts on Daspletosaurus than they typically do, however it is still entertaining and has some facts for everyone.

The facts are well represented today though. If one chooses to read, you could visit ThoughtCo, the BBC, and even Enchanted Learning (if you want a very quick sheet of facts that are kid-friendly). A more in depth discussion of facts is also available in the I Know Dino podcast's Dino of the Day. This is available on YouTube:

15 September 2018

The Frightful Lizard

The "Frightful Lizard", Daspletosaurus consists of two recognized species: D. torosus Russell 1970 and D. horneri Carr et al. 2017. Daspletosaurus was at the top of its game during the Late  Cretaceous approximately 77 to 74 million years ago. Fossils of Daspletosaurus have been found in Alberta (D. torosus) and Montana (D. horneri) and are contemporaneous with Gorgosaurus, Centrasaurus, Hypacrosaurus, Brachylophosaurus, and Albertaceratops, among others. It is hypothesized that Gorgosaurus and Daspletosaurus may not have been in direct competition as apex predators, allowing for some niche partitioning that enabled them to live in the same areas at the same time without out-competing one another. As the more robust of the two genera, Daspletosaurus may have been more likely to prey on the more physically robust and difficult to take down ceratopsians than hadrosaurs; leaving hadrosaurs for lean times and Gorgosaurus.
©Dmitry Bogdanov

09 September 2018

Different -aroo

The kangaroos now exists as two species in one genus in Australia (and outside too as zoo animals and, increasingly, as pets). However, like any living animal, the kangaroos have ancestors, and a lot of them were very interesting. There have been kangaroos that walked instead of hopping and there have been kangaroos with rather large fangs. Most of those kangaroo ancestors have a -roo ending, which makes for some interesting names as well. One of the newest of these animals is the first true kangaroo known from 23 million years ago. This kangaroo, Cookeroo (divided into two species: C. bulwidarri and C. hortusensis), is also thought to have walked and scurried rather than hopped across the Australian landscape. These hypotheses are based mainly off of phylogenetic position (based on what I have found), as the paper describing the fossils describes numerous skulls, which are mostly incomplete, though some are fairly complete.
Holotype of Cookeroo bulwidarriPhoto posted by Dr. Kaylene Butler

04 September 2018

I Forgot Yesterday

Yesterday I had a video with Jeffrey Wilson all lined up and then I forgot to post it. So therefore, here today is Dr. Wilson talking about the large sauropod eating snake Sanajeh. He is seated next to a sculpture of the fossil which, in my opinion, is pretty fantastic. The fact that the fossil itself depicted this scene is one of the fascinating things about paleontology. Not only do we sometimes find new animals in fossil deposits, but sometimes, such as with Sanajeh, we get to see a scene of nature's beauty and ferocity frozen in time forever. Enjoy the video:

02 September 2018

Dinosaur Train Facts

Dinosaur Train delivered facts are always a nice short video full of facts that we can rely on. If that video is not enough there is also the ThoughtCo fact page.

01 September 2018

Snakes and Fossils

In 2010 Jeffrey Wilson and colleagues described a fossil snake found in the Western Indian state of Gujarat outside the village of Dholi Dungri. That snake is known as "Ancient Gape" or, in Sanskrit, Sanajeh indicus (indicus coming from the Latin meaning from India). The snake was discovered coiled around sauropod eggs, with an additional 50 cm long sauropod body found nearby. This Late Cretaceous snake, a Madtsoiid or Gondwanan clade snake, is thought to have regularly preyed on sauropods because of this discovery. Vertebrae, ribs, and a very rare but very fortunate nearly complete cranium including the lower jaw were discovered in this fossil. In extant snakes the head is extremely loosely connected together, as it was in Sanajeh. Even now these modern snakes are rarely found intact because of these loose connections. The fact that Sanajeh was discovered with a nearly complete skull and jaws is remarkable, and, as we can see in the line drawing of the fossil, uncovering this find must have been fairly fantastic.
From Wilson et al., 2010

31 August 2018

Imagery

The majority of posts lately have been the kind of posts I can do with minimal research, you may have noticed. This is because I am doing a lot more work in my personal life and career than I had been doing previously. That sounds like I was lazy before, but that's not what I intended. At any rate, you can continue to expect a number of posts a week still, which is why we all visit the page to begin with. Today, for example, the simple posting you see here is one of the more interesting images of this small ornithischian ball of feathers. All of the artistic impressions of Kulindadromeus appear to have taken the feathering to an extreme such that the dinosaur looks less like a dinosaur than it does a small chicken or duck chick. My favorite version of these fluffy versions of Kulindadromeus is Jed Taylor's watercolor-esque duo which he posted on Twitter. These two are less fluffed than other versions and there is a somewhat abrupt appearing end of the feathers at the base of the tail. If you have a favorite share them in the comments below.
©Jed Taylor

27 August 2018

More Popular Movies

Yesterday I posted some fact videos. Today, there are some informational videos that tell you about reconstructing the dinosaur and the feather structures that were discovered in the fossil material.


26 August 2018

A Runner in Motion

On this beautiful, but very hot, Sunday, watch some nice fact videos and a slideshow of scientific illustrations of Kulindadromeus. Do not let my short entry here belittle the facts on these videos:

I Know Dino:

WizScience:

"Tribute" video:

25 August 2018

All Feathered

Kulindadromeus zabaikalicus (Runner of Kulinda + the Russian subject of Zabaykalsky Krai) was a Jurassic ornithischian, an herbivore, and was found in Russia and described in 2014 by Godefroit et al. These are all rather uninteresting facts; however, Kulindadromeus is a very important dinosaur. This dinosaur was discovered with traces of its integument evident with the fossil. That integument is consistent with the structure of protofeathers that have been discovered in a number of Coelurosaurian dinosaurs, early birds, and dromaeosaurs. The discovery of feathers in a non-avian line dinosaur indicates that the protofeather may have been a characteristic that was basal to all dinosaurs and not just the dinosaur family tree that eventually took flight.
©Nobu Tamura

13 August 2018

Living Relatives

The Chacoan peccary (Catagonus wagneri) of Paraguay, Bolivia, and Argentina numbers approximately 3,000 animals remaining in the wild. This is important for a number of reasons, but the most important reason for us today is that, as the closest remaining descendant (hypothesized) of Platygonus, it is a stand in for our fossil peccary. Though smaller than its extinct ancestor genus Platygonus, Catagonus shares an interesting part of its known history with Platygonus. The Chacoan peccary was initially described as an extinct animal of South American in 1930. It was not until 1971 that living examples of the peccary were found by non-native scientists. The native people of Argentina showed the animals, which they called tagua, to biologists that were in the area. This video shows images of the tagua or Chacoan peccary, which stands in for its ancestor Platygonus.

11 August 2018

New Week

I intended to discuss the book Unnatural Selection more than I was able to last week, but I received an email that has kept me fairly bust since last Monday or Tuesday. Instead of spending multiple weeks on the book, I thought that this week we could di○scuss a fossil ancestor of one of the animals that is highly important to discussions in the book about selective breeding. We have discussed the origins of cats and dogs a number of times here and we have also discussed more than a few early birds, their cousins, and their ancestors. The remaining group that I had mentioned from the book is that lovable farm (and table group), the pigs (a magical animal, as regards the table comment).

Suidae consists of a large group of animals, both domesticated and feral, today. At one point we tried to discuss the origin of pigs, but they are a diverse group of animals that have evolved into 17 species across 6 genera and a wide variety of sizes and diets. Also, it was a two entry week, because I was extremely busy, in which we discussed Strozzi's Pig (Sus strozzi). The story of the evolution of the domesticated pig begins with the wild boar (Sus scrofa) and Strozzi's pig is a step along the road between ancient relative and modern pigs. Part of the reason Strozzi's pig died out is actually tied to surges in the population of S. scrofa. Going farther back on the family tree is somewhat problematic, but entertaining because the clade that all pigs and boars belong to is called Artiofabula which welcomes its own puns. Despite all we know about living pigs and boars and having a general idea about their familial relationships, there is not that much known about the origins of Suiidae itself. However, because we had a brief discussion about S. scrofa and domestication before, we are going to talk this week about an ancestor of the peccaries, rather than the wild boar.

Peccaries of the family Tayassuidae in the group of Suidae are the only pigs native to the Americas. Historically measuring approximately 90 and 130 cm (3.0 and 4.3 ft) in length and about 20 to 40 kg (44 to 88 lb), peccaries are smaller than boars and domesticated pigs. Wild pigs and boars in the United States, for instance, are not peccaries but feral versions of the domesticated pigs that came over with European settlers. One of the most well-known wild suids in the United States, the javelina, is a peccary though. Confusion between feral domesticated pigs and peccaries is very common. Regardless, peccaries have their own rich history in North America. One of the extinct members of the family, Platygonus, consists of 18 described species of ranging from Canada to Mexico and California to Pennsylvania throughout the Pliocene and into the Pleistocene. Platygonus was rather large for a peccary at 1 m (3.3 ft) long. Long legs made it capable of running at a fair speed and tusks allowed it to defend itself from predators. It is thought that these peccaries lived in herds as well, making them a bit more well protected than solitary pig and peccary species.

©Charles R. Knight, Platygonus leptorhinus

05 August 2018

Classy Introductions

In order to name something, you need to be able to define the parameters of that thing — to know categorically when it ceases to be one thing and becomes another.
- Page 8, Unnatural Selection 

Every science text that aims to cross over to popular nonfiction work needs to have a very good introduction that not only grabs the reader's attention but also explains the basic tenets of the book's context in a way in which non-scientist readers can follow along and apply the fundamentals of these ideas. Application can be either within the text or outside of the book. Most authors that care about teaching their audience (we hope all authors, of course) spend a great deal of time explaining these basic principles of their text to make this process easier. The first few chapters of Unnatural Selection outline some of the basic principles of evolutionary science including basic lessons in phylogenetics, speciation, and a basic understanding of plasticity.

I did not mention this yesterday, however, Unnatural Selection is a book that focuses primarily on the phenomenon of dometication in its various forms, that is from the development of livestock to pigeon fanciering and from dog breeding to the very complex nature of swine domestication and hybridization. To sum it up more succinctly, the book is about selective breeding, and the basic principles of how we name animals, how they are related, and how this breeding process has worked over time are very important to understanding the later chapters of the book. Therefore, the first section of the book, in which these principles are taught to the reader, are very important. They are, fortunately, very well written.

As an example, the sometimes difficult to explain concept of organismal plasticity is written such that it is fairly easy to follow as well. In the scope of the book (that is in its use in describing selective breeding), a slightly different definition is used than that of the strict biological definition of the word. In that strict biological sense of the word we are looking at a phenotypic plasticity or the adaptability of an organism to changes in its environment. Unnatural Selection approaches plasticity in terms of the potential for changes over generations, rather than in a single generation. We could say the difference is that between an animal that experiences an environmental change over its life (for a myriad list of reasons hypothetical or otherwise) compared to the changes of a dog (cat, pig, pigeon, parakeet) breed over successive generations (see below for change over time in Bullterrier skulls). That breed can change in many different ways for a variety of reasons including, as van Grouw says, "fashions might simply change." Additionally, because these animals are all interbreeding subspecies, those plastic changes can flip, flop, and twist in amazingly interesting ways over the years because of the breeding of mutts and mixes of purebreeds that become fashionable (think of things like Labradoodles).

©Katrina van Grouw

04 August 2018

Skeletons and Popular Literature

A few years ago a book was written called The Unfeathered Bird that was focused on the anatomy of birds, showing birds as they are not often seen in popular literature. The illustrations for the book were hand-drawn skeletal, muscle, and even some feathered images of a wide array of birds, highlighting differences and similarities across a wide range of birds; hitting every bird in this manner would be a life's work and well beyond the scope of a single book. A follow-up work by the author and illustrator Katrina van Grouw was recently published titled Unnatural Selection. Though not a follow-up in the sense of focusing on birds, Unnatural Selection does continue as an investigation of evolution, anatomy, and high quality illustration of a wide range of animals. Over the next week I am going to go over some of the chapters of the book. We will also get to see some of the illustrations that grace the pages of the book.

We can get back to fossil animals next week.

26 July 2018

Fame and Mice

As we have stated this week, Mussaurus is well-known among paleontologists and it is actually fairly well-known by the public as well. This is partly because of its bogus claim of being the smallest dinosaur; granted it was the smallest known dinosaur when originally discovered and the hatchlings and juveniles are still quite small for dinosaurs. The sheer number of websites with information, images, and videos of Mussaurus attests to the dinosaur's popularity. If that was not enough, there is also an electronic toy version of the dinosaur and, back after not seeing one of these information trading cards in a long time, Mussaurus is featured below, looking very angry for some reason.

24 July 2018

Anatomy of A Mouse Lizard

The first article that appears in a Google Scholar search for Mussaurus is Pol and Powell's 2011 paper Skull anatomy of Mussaurus patagonicus (Dinosauria: Sauropodomorpha) from the Late Triassic of Patagonia. Starting off with the cranium is the right way to go (my research is concerned with the skull, in case anyone wasn't aware). Because there are so many specimens of Mussaurus known to us, there is a lot of the skeleton that is known as well; the head is just the beginning. In fact, Pol also helped to describe some of the postcranial anatomy as well (Otero and Pol, 2013). Like Pol, Mussaurus is known from Argentina, which partially explains why he has been involved in numerous papers on the small dinosaur including Cerda et al., 2014a, Cerda et al., 2014b, and Otero et al., 2017 in addition to the two mentioned above. These studies are all largely descriptions of anatomy, generally either skeletal or joint related. This is not the limit of studies on Mussaurus of course.

Mussaurus had its own profile in the 1993 book Age of Dinosaurs by Peter Dodson which briefly discussed all the details that were known of small dinosaur at that point. Many studies not describing skeletal or joint attributes directly have also been published on Mussaurus that rely heavily on those descriptions, a prime example being Montague, 2006 which generated estimates of body size for over 600 dinosaur species, including Mussaurus. Phylogenetic analyses have been conducted using these descriptions and anatomical characters also; see Upchurch et al., 2007. Lastly, we know that the nests have been described, notably in Bonaparte and Vince, 1979, the paper initially describing Mussaurus from juvenile and infant specimens found in the nest that forms the basis of the title and bulk of the paper. This occurrence of the first Triassic nest on record is significant beyond just the naming of Mussaurus of course. Dinosaur eggs have been known since at least 1923 when the American Museum of Natural History led expedition of Mongolia discovered supposed Protoceratops nests; these led to the naming of Oviraptor and eventually it was discovered that the nest belonged to Oviraptor rather than Protoceratops (another story for another day). This nest, that of Mussaurus, is one of the earliest known dinosaur nests and an important link in the story of dinosaur evolution. Also we can all agree that dinosaur nests are pretty cool and that the earliest dinosaur nests and their tiny occupants are also very cool.

References:
Bonaparte, J.F. and Martin, V., 1979. El hallazgo del primer nido de dinosaurios triasicos,(Saurischia, Prosauropoda), Triásico superior de Patagonia, Argentina. Ameghiniana, 16(1-2), pp.173-182.
 
Cerda, I.A., Chinsamy, A. and Pol, D., 2014a. Unusual endosteally formed bone tissue in a Patagonian basal sauropodomorph dinosaur. The Anatomical Record, 297(8), pp.1385-1391.
 
Cerda, I.A., Pol, D. and Chinsamy, A., 2014b. Osteohistological insight into the early stages of growth in Mussaurus patagonicus (Dinosauria, Sauropodomorpha). Historical Biology, 26(1), pp.110-121.
 
Dodson, P., 1993. Age of Dinosaurs. Publications International Limited.
 
Montague, J.R., 2006. Estimates of Body Size and Geological Time of Origin for 612 Dinosaur Genera (Saurischia, Ornithischia). Florida Scientist, pp.243-257.
 
Otero, A., Allen, V., Pol, D. and Hutchinson, J.R., 2017. Forelimb muscle and joint actions in Archosauria: insights from Crocodylus johnstoni (Pseudosuchia) and Mussaurus patagonicus (Sauropodomorpha). PeerJ, 5, p.e3976.
 
Otero, A. and Pol, D., 2013. Postcranial anatomy and phylogenetic relationships of Mussaurus patagonicus (Dinosauria, Sauropodomorpha). Journal of Vertebrate Paleontology, 33(5), pp.1138-1168.
 
Pol, D. and Powell, J.E., 2007. Skull anatomy of Mussaurus patagonicus (Dinosauria: Sauropodomorpha) from the Late Triassic of Patagonia. Historical Biology, 19(1), pp.125-144.
 
Upchurch, P., Barrett, P.M. and Galton, P.M., 2007. A phylogenetic analysis of basal sauropodomorph relationships: implications for the origin of sauropod dinosaurs. Special Papers in Palaeontology, 77, p.57.
 

23 July 2018

Mouse Movement

Mussaurus is not a movie star, despite it being a recognizable dinosaur for many people in and out of the paleontological profession. It has been studied and a video showing its range of movement has been posted online by John Hutchinson, author of What's in John's Freezer? and well known locomotion expert known for studying a wide range of animals, fossil and extant, among other topics (see his biographical blurb on his faculty website). Tomorrow there will be a lot more to read than there is to watch today; so do not feel like the mighty Mussaurus is under-represented yet!

22 July 2018

Cute Titles

Mussaurus lends itself to cute titles on webpages. One such page, from Mental Floss, is title 10 Mousey Facts about Mussaurus. The facts on this site address issues like the size of the animal and the misinterpretation of the remains as well as other issues in a serious manner; not at all what one expects from a cute website title. These facts are again summarized in a WizScience video, for folks without the time to read websites right now. However, if websites are your Sunday morning or afternoon reading material, there are far more than just the Mental Floss page shared above. There are also pages on Mussaurus on Enchanted Learning, KidsDinos, Prehistoric Wildlife, and a number of other pages (though this may be enough Mussaurus for most people in a day!).

21 July 2018

The Mouse Lizard

Reaching an estimated 3 m (10 ft) in length and 70 kg (150 lbs) in weight, the early sauropodomorph Mussaurus patagonicus was an aptly named dinosaur. The name means "Mouse Lizard" and was applied originally to the skeletons of infants, which are considerably smaller at 20 to 37 centimeters (7.9 to 14.6 in) long, because these were the only specimens known for a fairly long time. Some of the first adult specimens were found alongside or within nests of the already known juvenile and infant dinosaurs. Eggs of this species have also been found in some of these nests. The original juvenile specimens were described in 1979 and the first adult specimens were not described until 2013. The first adult specimens in this description were actually reassigned from Plateosaurus specimens that were described mistakenly in 1980. Their similarities make sense because both were early dinosaurs and both were early sauropodomorphs.
©Henrique Paes

19 July 2018

Known but not Famous

I mentioned on Tuesday that Staurikosaurus is a much published and important dinosaur in the scientific community. Outside of the scientific community the knowledge about, and reaction to, the existence of Staurikosaurus is minimal at best. Staurikosaurus does appear in a number of popular arenas, including the video game on the original PlayStation (see the video below at 5:39 for this version of Staurikosaurus). One place we know that people know about Staurikosaurus for sure is Brazil, where the animal was originally discovered and unearthed. Canela, a town near the discovery site, has a statue of Staurikosaurus alongside a small rhynchosaur.
Photo by Sergio Kaminski, CC BY-SA 3.0

17 July 2018

Papers and Beyond

Staurikosaurus headlines a chapter in an older edition of the book The Dinosauria. This chapter has been replaced in newer editions of the book, but the importance of Staurikosaurus and the many papers discussing the anatomy and the phylogeny of Staurikosaurus remain in the newly re-designated chapters. These include the papers that initially described the holotype fossil (Colbert 1970) and estimates of missing elements of the skeleton (Grillo and Azevedo, 2011b) as well as those that ask questions about the origin of saurischian dinosaurs and Staurikosaurus' placement in this discussion (e.g. Galton, 2000). Staurikosaurus continues to be studied beyond the skeleton and its phylogenetic importance to the evolution of dinosaurs also. Grillo and Azevedo (2011a) studied the pelvis and hindlimb to describe the state of the musculature in these areas. These papers should be plenty for a day's reading, so enjoy learning more about the anatomy of Staurikosaurus and where this dinosaur sits in the dinosaur family tree!

References:
Colbert, E.H., Price, L.I. and White, T.E., 1970. A saurischian dinosaur from the Triassic of Brazil. American Museum novitates; no. 2405.

Galton, P.M., 2000. Are Spondylosoma and Staurikosaurus (Santa Maria Formation, Middle-Upper Triassic, Brazil) the oldest saurischian dinosaurs?. PalZ, 74(3), pp.393-423.
 
Bittencourt, J.D.S. and Kellner, A.W.A., 2009. The anatomy and phylogenetic position of the Triassic dinosaur Staurikosaurus pricei Colbert, 1970. Zootaxa, 2079(1), p.e56.
 
Grillo, O.N. and Azevedo, S.A., 2011. Pelvic and hind limb musculature of Staurikosaurus pricei (Dinosauria: Saurischia). Anais da Academia Brasileira de Ciências, 83(1), pp.73-98.
 
Grillo, O.N. and Azevedo, S.A., 2011. Recovering missing data: estimating position and size of caudal vertebrae in Staurikosaurus pricei Colbert, 1970. Anais da Academia Brasileira de Ciências, 83(1), pp.61-72.

15 July 2018

Short Video

Staurikosaurus is not very well known, in terms of media presence and general availability of quality fact pages on the internet. There are a few notable pages, such as the NHM in London, KidsDinos, and the DinosaurFacts website. These pages are all summarized, for the most part, in the WizScience slide show/video that has been made for Staurikosaurus shown below.

14 July 2018

Brazilian Theropod

Herrerasaurids make up some of the earliest dinosaurs and the earliest theropod dinosaurs as well. These small carnivorous bipeds are known for their agile appearances and small stature as well as their basal characteristics that laid the groundwork for their descendants, even some of the characteristics that can be found in the latest theropods like tyrannosaurids and abelisaurids. These characteristics were modified over time of course, but the changes can be traced back to these small herrerasaurid dinosaurs that have mostly be found in South America from a number of different locations. One of these locations, in Brazil, was the discovery site of an animal known as the "Southern Cross lizard", Staurikosaurus pricei. The specific epithet honors one of Brazil's first paleontologists, Llewellyn Ivor Price, who collected the fossil which was later described by Edwin H. Colbert. Staurikosaurus was Brazil's first discovered and described dinosaur, but has remained a very uncommon find, meaning that either it was not native to an area that allowed for easy fossilization (such as a forest) or was simply uncommon in its environment.

Staurikosaurus was one of the first dinosaurs and that makes its fossilized remains just as important in understanding the rise of dinosaurs as those of Herrerasaurus and other dinosaurs considered to be the first members of the dinosaur clade. Its long slender limbs appear to have been well equipped for running; forelimbs are missing from the fossil record so we do not know if was good at catching its prey. We do know that its jaw was filled with many serrated and recurved (curved toward the back of the skull) teeth, so it could have caught prey with its mouth rather than with hands. These teeth were also able to slice into its prey. As far as predators of the Late Triassic are concerned, Staurikosaurus was likely a fearsome foe for many smaller reptiles and mammals that it lived with.
©Nobu Tamura

12 July 2018

Socketed Teeth

Thecodontosaurus was named for its teeth. Thecodont teeth are situated so that the base is completely enclosed in a bony socket, like our teeth and the teeth of other mammals, crocodilians, and dinosaurs. To help visualize this refer to the image below.
The specific epithet refers to the ancient age of the animal. John Morris, the English geologist who provided the specific epithet in 1843, simply appended the name antiquus to Thecodontosaurus, attributing the name to Henry Riley, the surgeon who helped with the excavation, without any explanation. Therefore we do not know what Morris was referencing with the name T. antiquus. It could be either the fact that it was a fossil animal or that it came from Triassic rock. We may not know any time soon.

Over 245 fragmentary specimens of Thecodontosaurus are known, all attributed to this single species; not for a lack of trying though as 14 other species have been named only to be reassigned to other genera or re-folded into the single valid species. A second species was speculated in 2000 by Benton et al., 2000 when observing more robust specimens of Thecodontosaurus. In the same paper the authors stated that the more robust morphology was equally as likely a result of sexual dimorphism as it was a potential additional species. Regardless of the findings of the paper as regards sexual dimorphism or secondary species, two morphologies are acknowledged simply as gracile and robust.

09 July 2018

A Short Short

Thecodontosaurus is not very famous in terms of on film presence (for many dinosaurs this translates simply into "not very famous" at all). However, the University of Bristol started a program in 2000 to engage and educate the public using the research and expertise of university faculty in conjunction with local (and global) fossils and the research that has gone into them. Thecodontosaurus is a dinosaur that was featured heavily in the Bristol Dinosaur Project because it was a very local (read found near, around, and in Bristol) dinosaur that made for an engaging animal in the initial stages of the growth of the Bristol Dinosaur Project; the project originally centered around the recovery and preparation of Thecodontosaurus specimens in addition to the outreach components conducted by the faculty. In fact, the mission statement is still mostly concerned with laboratory work on Thecodontosaurus specimens, but the outreach component appears to continue to be a very valuable portion of the work. The website is a little outdated and other news sources only cover up to the funding cycle for 2013, though the Bristol Zoo (which partnered with the university for some time) last mentions their dinosaur exhibit during the summer of 2017, so there is hope. Anyone that knows more about the project's current state is encouraged to share more with us, but we can only hope that a wide-reaching scientific and educational project like this is still in effect.

08 July 2018

A Learning Video

WizScience with a summary video of facts for you to learn some more general information about Thecodontosaurus on this wonderful Sunday:
Additionally, there are a number of pages that have fact files, many different visual interpretations, and a fair bit of discussion about the dinosaur and what we know about it.

07 July 2018

Thecodontosaurs

An early socket-toothed sauropod, Thecodontosaurus antiquus Morris, 1843, was discovered in Southern England from Late Triassic (227-205 million years ago) soils around 1834. As many of these stories go, the people that found the remains were academics that could have been called doctors, naturalists, or scientists, depending on the definition they decided to use. A surgeon, Henry Riley, and the curator of the Bristol Institution for the Advancement of Science, Literature, and the Arts, Samuel Stutchbury conducted an expedition in a Bristol quarry where "saurian remains" were reported. Most of a skull was recovered, leading to descriptions of the teeth and name of the animal: Thecodontosaurus meaning "socket-toothed lizard", referencing the way in which the teeth were socketed in the jaws. 

Other fragments of the fossils represented various portions of the entire skeleton including the neck and "body" (ribcage and vertebrae), forelimbs, and legs led the initial description to identify Thecodontosaurus as a dinosaur; the fifth known and named dinosaur in fact. This diagnosis has not changed (some dinosaurs and non-dinosaurs identified in the earliest days of paleontology have been rediagnosed any number of times in the past 200 years) and has actually been supported by more material being recovered and identified. This is a good thing for many reasons, including that the holotype was destroyed in a 1940 bombing raid of Bristol by the German Luftwaffe.


05 July 2018

Fame and the Dinosaur

Tawa hallae is a famous early theropod not only because of its coverage by the National Science Foundation or the publication of its description in Science. Tawa is also famous because it was an early theropod situated between the earliest theropod dinosaurs we know, animals like Herrerasaurus and Eoraptor, and the previously considered base of the theropod tree: Coelophysis and its family members. In a way that makes Tawa a kind of "missing link" (a term that scientists do not generally actually like using because it has been so warped). Tawa may be a link between those South American theropods and the rest of the theropod family, but that does not mean it is the only link nor that it is the most important link. The fame that its current status has given it, though, has been immortalized in books, television, online videos, and it has even become a model and toy that is loved by many children (and adults); there is even a new model for this year.

03 July 2018

Science Descriptions

When an article appears in Science it is typically accessible forever. In terms of Tawa hallae this is very good news for us because the describing and naming paper are housed and available on the website. The paper is stored as a PDF and as html (Nesbitt et al., 2009), which is nice when you do not want to download another PDF and instead just want to read a paper on your screen. The high resolution photographs of bone and approximated skeletal drawings are available too in this format. This is not the only paper to describe Tawa or its family line though. There are a number of other descriptions of Triassic animals that call upon Tawa and other known dinosaurs for comparisons. However, the other paper linked here today is a little more inference based in that it discuss soft tissues of Tawa that are not actually preserved in the fossils. Instead, Burch 2014 uses osteological correlates of muscle attachments and inferences from extant phylogenetic brackets to reconstruct the muscles of the forelimb in Tawa. These kinds of studies are of interest to me because I have done similar things in the head, but muscle reconstruction in dinosaurs, even if one does not do this type of work themselves, is interesting and important in learning how dinosaurs lived, survived, and died in their environment.

01 July 2018

Tawa and the National Science Foundation

The National Science Foundation (NSF) was all over the discovery and naming of Tawa hallae, with good reasons, and because of their coverage we have an entire page of videos on not only the dinosaur but also the discovery and an interview with Sterling Nesbitt, who led the paper naming the fossil. Rather than pasting all of the videos into today's entry, the NSF has been kind enough to place all of the videos on the same page, so we only have to use a single link. Also, rather than describe each video here, the NSF page has done that for us as well. There is a lot of information on this page, and it doesn't take a whole day to go over it, so enjoy the videos and information and then enjoy a Sunday outside, or watching the World Cup; whatever you enjoy!

30 June 2018

Coming Back with A Sun God

First, it is really nice to be able to sit and write something for this page again. The past few months it has been difficult to work on writing all day long and then have any energy at the end of the day to write for the page. However, this week, at least, I can spend some time and brain power on writing for the page. This is a good thing.

This week we are going to go back a little further in time and talk about an animal that has, as I find it, strangely not made its way onto the page before. Named for the Hopi word for the sun god of the (all, not just Hopi) Pueblo people and the founder of the Ghost Ranch Museum of Paleontology, Ruth Hall, Tawa hallae was a small Triassic theropod contemporaneous with Dromomeron, Chindesaurus, and potentially even the well-known dinosaur Coelophysis. Tawa is known from a number of different skeletons, none of which are entirely complete, and the initial fossils are thought to be from a juvenile specimen, meaning that the pieced together full version of the animal, weighing in at 15 kg (33 lb) and measuring 2.5 m (8 ft 2 in), is a rough estimate of adult size. The difference between known juvenile and estimated adult size leaves us with a gracile early theropod dinosaur somewhere in the size vicinity of corgi in weight but a golden retriever or a slightly larger dog in height; lengths do not translate to dogs well so I do not know what to give you as a comparison for that measurement.

©Nobu Tamura
Despite living 215-213 million years ago and being one of the more successful carnivores of its day, the size of Tawa was nothing to some of the chief herbivores of the day, such as Plateosaurus (214 to 204 million years ago). Though these two animals may have never crossed paths (Plateosaurus is known from European fossils and Tawa from North American fossils exclusively), the size difference would have likely made it nearly impossible for Tawa to prey on a healthy individual because it was a full 2.3 m (8 ft) shorter and 585 kg (567 lb) lighter than the smallest known Plateosaurus. Sick and injured individuals are always a different story and perhaps Tawa had some way of dealing with large prey like this that we do not know about yet. Regardless, I bring this up only to state that not all of the animals of the Triassic were small and that early dinosaurs were already attaining rather varied sizes. The diet of Tawa was not reliant on such large animals, however, as other small archosaurs, therapsids, insects, phytosaurs, and many other animals were available as part of the diet of this small (for a theropod) carnivore.

28 May 2018

Bit Role Star

Rhamphorhynchus appears in two popular films for brief periods in each. The first, One Million Years B. C. is vintage Ray Harryhausen stop motion work with a very inaccurate version of Rhamphorhynchus attacking a Pteranodon. Despite its terrible inaccuracies it is an intriguing interpretation of the animal. Also it eats the Pteranodon nestlings, which is peculiar and very much outside of its inferred diet. The second appearance of Rhamphorhynchus that is probably better known is from Walking With Dinosaurs (Ep. 3 Cruel Sea) in which it is shown skimming the surface of the water for small fish. There are a number of reasons this is a strange portrayal, and time permitting, we will get into them later this week. For now, though, enjoy these two clips:


27 May 2018

Night Flying

If a niche exists in nature, some animal somewhere is, was, or will be an expert in that lifestyle. During the Jurassic Laurasia, the northern supercontinent, was populated by a number of pterosaurs that possessed different body shapes and populated different niches. Many different characteristics of these fossil flyers have led researchers to many inferences of diet, flying style, and even time of activity; for example, the scleral rings and orbit shape of Rhamphorhynchus are a key characteristic leading researchers to infer a nocturnal lifestyle. The long-tailed pterosaur has been discovered across Europe and in parts of Africa in deposits that represent shoreline and off-shore environments. The localities, along with cephalopods and fish that have been recovered from both gut areas and coprolites (fossilized feces), point to Rhamphorhynchus as an ocean-going pterosaur. Consisting of three recognized species (R. longicaudus Münster, 1839 (type specimen) , R. muensteri Goldfuss, 1831 (originally Ornithocephalus) and R. etchesi O'Sullivan and Martill, 2015), Rhamphorhynchus was a small (1.26 m, 4.1 ft long; wingspan: 1.81 m, 5.9 ft) needle-toothed pterosaur lacking a crest and possessing a long tail, something pterydactyloid pterosaurs (the kind most people think of when they think of pterosaurs) noticeably lack. The tail, in fact, is the origin of the specific epithet of the type species, R. longicaudus.
Louis Figuier, 1863

22 May 2018

Yates Description

As with many dinosaurs, there are a number of papers that mention Dracovenator, far more than the number of papers that actually focus all of their attention on our featured dinosaur. The description of Dracovenator by Yates (2005) is detailed, including line drawings, detailed photographs, and even a character list of attributes at the end of the article. As with many descriptions, the article is a little dry, but that is the nature of descriptive paleontology, so it does not make the article bad or otherwise lacking some sort of thrill found in other papers describing fossils. I am kind of a fan of the image of the juvenile fossil displayed upright as it is not often that we are shown the flat side of fossils in papers in this manner.

Yates, A. M. (2005). A new theropod dinosaur from the Early Jurassic of South Africa and its implications for the early evolution of theropods. Palaeontologia Africana 41:105-122

20 May 2018

Dragon Hunters

Dinosaurs and fossil hunters have been referred to as dragons and dragon hunters for centuries now; however, there is only one dinosaur whose name means "Dragon Hunter": Dracovenator regenti Yates 2005. A dilophosaurid discovered in the South African foothills of Drakensberg ("Dragon's Mountain": Dutch), Dracovenator consists of cranial material from early Jurassic rocks near the borders of Lesotho, a small country contained within South Africa. The characteristic shape of a dilophosaurid skull is apparent in the remains of Dracovenator in both the adult (holotype) and referred juvenile materials (reassigned from Syntarsus to Dracovenator by Munyikwa and Raath 1999). The estimated size of Dracovenator, extrapolated from related animal sizes and the cranial material available, is between 5.5 and 7 meters (18 and 23 ft) from snout to tail and weighing upwards of 400 kg (882 lbs).

18 May 2018

Dynamic Images?

What is the most dynamic, awe-inspiring image of Tuojiangosaurus that one can find on the internet? There are a near infinite number of opinions regarding which image and why any particular image might be the most beautiful or amazing image of Tuojiangosaurus. The images could come from anywhere also. This includes skeletal mounts, 3D video game renders, ink drawings, and any other media one can think of. My personal favorite was a hard choice this week. I always love the old-fashioned (like Charles R. Knight style) sorts of drawings, but Tuojiangosaurus was not discovered until 1977. Conversely, I appreciate really well done computer generated media as well, of which there is plenty representing Tuojiangosaurus. The image I have chosen as my favorite of the lot comes from the latter category today, and specifically it is attributed to Román García Mora. Even though the artwork is attributed to Mr. Mora, it does not appear on his website, linked above. Maybe more unfortunate, the image was originally found on a fourth party site and therefore even farther from the artist's control.
©Román García Mora

14 May 2018

Fun to Type

Tuojiangosaurus is actually fairly easy to spell after the first two or three times you type it out: fun personal observational fact/opinion that I just decided upon. If anyone disagrees, I can completely understand why, but give it a few more tries before you give up. Additionally, despite searching the blog the other day to see if we had covered this animal before and for some reason nothing seemed to show up, I noticed today that we had covered it, six years ago. However, revisiting old friends now and again is always interesting and fun. An even more fun fact about that time is that I found out that I was accepted to the biology graduate program at Fort Hays, which means that Tuojiangosaurus was the first dinosaur we discussed during my non-educator focused graduate career. Pretty neat stuff there. Anyway, on to the important aspects of why anyone opens this page on a Monday: movies about the animal we are featuring this week.

Back in 2012 there were not many, if any, videos of Tuojiangosaurus on the internet, a point that I noted by sharing the one short documentary I could find at the time that discusses Tuojiangosaurus in any detail (the 9:18 clip is featured below again today and our stegosaur appears at the 3:00 minute mark). Tuojiangosaurus now, though, appears in video game clips and short movies all over YouTube, but that is hardly the end of its representation online in video format. There is a video of an animatronic version of the Chinese stegosaur from the Henry Doorly Zoo (in Omaha, NE) and Brookfield Zoo's (in Chicago, IL) Dinosaurs Alive exhibits. This animatronic dinosaur exhibit can be found at many different zoos under the same or slightly different names at different times of the year; one of the series of photos I have shared here in the past was from the Memphis Zoo's version simply titled "Dinosaurs". The Tuojiangosaurus featured in the exhibit is a little less like the actual fossil than we would like. However, it does encourage people to look up the dinosaur and see what they should really be seeing (as opposed to what they did see), which is a good place to start educating more people about our favorite fossil animals. In a similar vein, this video from the Dinosaur Quest at the San Antonio River Mall shows fossil casts rather than animatronic dinosaurs.There are countless video game videos of the dinosaur surrounding the links shared here and the short clip below, but I will leave these to the reader to discover at their leisure or desire.

13 May 2018

Small Stegosaurs

Thinking and writing about Ceratosaurus over the last week made me think about the animals that would have been food items for Ceratosaurus. One of the most prominently discussed and featured food items for Ceratosaurus and its contemporary Allosaurus was the western North American dinosaur Stegosaurus. We have written about and discussed Stegosaurus here at least once by itself and a number of times in reference to other dinosaurs. We have also discussed some of its closest relatives (such as Kentrosaurus), but we have somehow missed talking about one of its best known, Asian, cousins, Tuojiangosaurus multispinus. The name refers to both the multiple spines along this stegosaur's body and its discovery near the Tuo River of central China within the Sichuan Province (yes, where the cuisine originated from). Watch the video below to learn some more important facts about Tuojiangosaurus:

10 May 2018

Ceratosaurus Anatomy

Ceratosaurus has an interesting set of ridges and horn-like structures on its skull that gave two of the species their specific epithets: C. nasicornis ("nose-horn") and C. magnicornis ("large-horn").  The purpose of the horn was originally thought, by Marsh, to have been a "most powerful weapon" used by the theropod in both offensive and defensive matters. Many others agreed including Gilmore in 1920, Norman in 1985, and Paul in 1988. To be fair, Norman and Paul were more specific, arguing that the horns may have been used in intraspecific combat and headbutting. Rowe and Gauthier (1990) put forward a display only function for the horns, which appears to be the most popular hypothesis concerning Ceratosaurus horns.The assumption with these rugosities as display ornamentations often includes discussion of potentially brightly colored soft tissues covering and otherwise associated with the osteological structures.
American Museum of Natural History
Photo by Wikicommons user Daderot, released into public domain under Creative Commons CC0 license

08 May 2018

Balancing Papers on Horns

Ceratosaurus is the star of a couple of books (I am a fan of Charles Gilmore's description of North American carnivores from 1920). More importantly, Ceratosaurus is the star of a large number of scientific studies. The large volume of work stems in part from some of the interesting ways in which the fossils have been discovered. These studies include unique discoveries that were somewhat unexpected in places like Portugal and Africa. Possibly the largest concentration of Ceratosaurus skeletons that are known and have been recovered and prepared come from the states of Colorado and Utah; there are a number of other finds in Wyoming and other areas of the North American West as well. Reading the numerous descriptions of new finds could take one all day, but it may be worth it. I offer here a few older readings from Hay, Marsh, and Madsen that describe new finds and restorations of Ceratosaurus skeletons. Other options worth reading include Henderson's ecological study centered on skull and tooth morphology and Bakker and Bir's contribution to the book Feathered Dragons edited by Currie, et al.; a chapter titled "Dinosaur crime scene investigations: theropod behavior at Como Bluff, Wyoming, and the evolution of birdness". Though not always a popular character, their chapter is well written and an interesting interpretation of theropod feeding locations and the clues left behind.

07 May 2018

Facts and Movies

Ceratosaurus is a charismatic theropod dinosaur. Aside from how much I like Ceratosaurus personally, it is very apparent that Hollywood and other paleontologists have a great deal of affection for and interest in this genus. That has led to many podcasts, movie roles (yes, even in the Jurassic Park no one likes), and appearances in documentaries. Some depictions of Ceratosaurus shown here are almost magical; by that I mean that often Ceratosaurus is portrayed as a dinosaur with a unicorn-like horn. The facts and fossils show that the horn is not much like a unicorn's horn at all, and, as stated yesterday, was quite variable across species within the genus and individuals. In One Million B.C. Ray Harryhausen said of his Ceratosaurus, its horn, and the other dinosaurs of the movie that his creations were not for "professors... who probably don't go to see these kinds of movies anyway."

06 May 2018

Favorite Oldies

One of my favorite theropod dinosaurs is the medium sized so-called "horned lizard" Ceratosaurus. A genus consisting of three recognized species (C. nasicornis Marsh, 1884 (type), C. dentisulcatus Madsen and Welles, 2000, C. magnicornis Madsen and Welles, 2000) and one junior synonym that has been applied to the type species, Ceratosaurus was a Jurassic carnivore sharing the landscape with large sauropods, stegosaurs, and allosaurs. Known from North America, Europe and Africa, Ceratosaurus was a widely distributed and successful predator eclipsed during its existence only by the larger and equally successful Allosaurus. Though we consider Ceratosaurus to be a medium sized predator in the context of all theropods, at 5.69 m (18.7 ft) long; C. nasicornis is fairly large; the largest species C. dentisulcatus is estimated at 7 m (23 ft) long. The feature responsible for the name of this dinosaur is a large rugosity on the dorsal surface of the muzzle that appears to some to look like a horn; the type material was more horn-like than some of the later discoveries, but for the most part these rugosities are variable and can look like anything from horns to small ridges. Because we have so many remains of these animals, their ecosystems, and their contemporaries we know a lot about their life history, ecology, and the world that was around them. We also know enough about their feeding ecology that we can build awesome museum displays like this one at theNatural History Museum of Utah.

04 May 2018

The Scary Face

When the characteristic feature of your existence, as a fossil that is known and described in science, is that the entire legitimacy of your existence in our knowledge is tainted by potential theft and other impropriety you do not get overburdened with a lot of respect or investigation. Of course fossils are not people so the skull of Minotaurasaurus does not actually feel any shame, guilt, or worry about the provenance of its discovery or how it was whisked away from Mongolia (or wherever in Asia it originated). The people involved, regardless of their status as buyer or seller, are subjected to arguments from both sides of the controversy; factions do indeed exist that say that keeping the fossil in a private collection is as morally correct as it is to rescue a fossil from a private collection. Articles and opinions are everywhere online and in paper journals as well as in newspapers and magazines (two of these linked articles are about the same specimen). Not all of these issues arise in other countries either. The United States of America has its fair share of dinosaur fossil legal battles throughout its history; the ownership of Sue the T. rex being the most famous one that I can think of right away.

Minotaurasaurus is not a Tyrannosaurus and it is not a fossil of North America. Instead, it represents a real and, unfortunately, growing problem, even if we do not hear about it daily in the news. The skull is actually very interesting because it looks a lot like many other ankylosaurs we knew of previously and this has caused a lot of researchers, such as Victoria Arbour and Phillip Currie, have reassigned Minotaurasaurus to another taxon, Tachia kielanae. Another study upheld the original description and nothing else has surfaced since that time. Regardless, the skull is not in a museum where all of these researchers can look at the original material and come to a solid conclusion. Until it is they, and we, will have to make due with casts and character lists and some photographs to compare the skull to other animals. Description can be tricky though, so this description may be contentious for a some time to come, unless another animal is discovered and can be studied more directly.
Photograph of a cast of the holotype material. Borrowed from Victoria Arbour's blog here.

01 May 2018

Two Sides to Read

The description of the lone known skull of Minotaurasaurus is hosted online. Miles and Miles 2009 was published in Current Science (an Indian journal published in conjunction with the Indian Academy of Sciences), not necessarily because it was not good enough for some of the typical venues of fossil description (such as the Journal of Vertebrate Paleontology), but because it was very controversial. An initial attempt to publish in a Polish journal was met with rejection. The rumor about how the skull was purchased is that one of the authors told the buyer it would be named after him if purchased and it was purchased without papers of provenance because they do not exist, not because they were lost or misplaced. The fossil is Mongolian but it was prepared in the United States of America and sold through a Japanese based fossil dealer. Nature published an article summarizing the trip that the fossil has taken to become a published fossil shortly after the description was released. The New Yorker preceded the Nature article in releasing a story on fossil dealers and the fossil trade. Their article goes into details about illicit fossil sales and discusses the seller of the Minotaurasaurus skull, possibly connecting him with another illicit fossil sale of Tarbosaurus.

29 April 2018

Possible Issues

Minotaurasaurus, whether because of legal issues or contested phylogeny, does not have a lot of presence on the internet. However, there are a few articles online written by Darren Naish and Brian Switek that cover a lot of the information that will be covered here throughout the week and present a number of facts that we have not introduced yet about Minotaurasaurus. Images labeled Minotaurasaurus can be found in many places as well, though this site has compiled a good amount of those images. Prehistoric Wildlife lists the information that we know about the dinosaur, but as that information is limited the page dedicated to Minotaurasaurus is also limited. The Dinochecker website is a bit more wordy, but presents basically the same information as Prehistoric Wildlife with some more detail.

28 April 2018

Back to Dinosaurs

It has been quiet around here lately; I have been busy working on other things that require more attention and have made it so I have not been putting much attention in here. However, I enjoy doing this and it is a welcome break from other projects. Plus, we are going to talk about dinosaurs again. More specifically, we re going to talk about large ugly armored dinosaurs again. Anything with a name meaning "man-bull reptile" can be assumed to be an ugly animal. Of course the name, Minotaurasaurus ramachandrani, is based off of the looks of the skull and Greek mythology. The way that this complete skull came to science is complicated, but the specific epithet honors the man (Vilayanur S. Ramachandran) responsible for making the fossil available to science. Because of the complicated history of this fossil, the origin is unknown, but the fossil is likely from the Gobi Desert. The legal status of the fossil is still contested, though not as visibly as it was a decade ago. These are all things that will need to be discussed this week because they are both important and still relevant on a regular basis; probably too often to be honest.
©Nobu Tamura CC BY 3.0

22 April 2018

Evolving Swine

As mentioned yesterday, there are not many links for any fossil pigs online. Instead, please enjoy a short video with facts about wild boar, which we know would have a slight resemblance to the history of the pig in question (Strozzi's Pig). Think of this history by proxy as a way to learn a bit about pigs that you may not already know.

21 April 2018

Pets Everywhere

We have discussed the origins of a large number of what are now very popular pets. We have looked at the origins of dogs, cats, rabbits, reptiles, fish, horses, turtles, and a lot of other animals. One group we have not looked at that has, at least recently, been more regularly miniaturized and taken from the farm to the living room in many areas: the domestic pig. Belonging to the family Suidae, the domesticated pig has a complicated and long lineage. The domesticated pig is in the genus Sus, a group of animals ranging back to the Miocene, though pigs of the family Suidae are certainly a considerable deal older, dating back to the Oligocene.

Picking pigs to discuss is actually a little more difficult than one mine imagine; there are variable sources of information on fossil pigs and there is actually a lot less information, in total, on fossil pigs than one might imagine as well. Many fossil pigs are known entirely from their teeth and a number are known from their skulls and teeth together. Regardless of how much is known of each fossil pig, there is not a great deal written about any fossil pigs online. There are a number of articles on Enteldonts, but these large artiodactyls are not actually a group of pigs. One pig that has a small internet presence, and we can use as a model for talking about pigs at large, is Strozzi's Pig (Sus strozzi). This pig was very porcine, pig-like, and, as is the case in many wild suids, Strozzi's Pig looked very much like a wild boar or a warthog. Strozzi's Pig was a Mediterranean animal, distantly related to the suids of Africa and closely related to its counterparts from Europe and Asia, which contributed to the displacement and eventual extinction of Strozzi's Pig.

19 April 2018

Not So Tiny

We saw earlier this week that Ray Harryhausen made a very nice stopmotion Eohippus for the film The Valley of Gwangi. The reason that the horse was so small is that it was a common misconception that the horse was the size of a Fox Terrier. Many sources have mentioned this size issue many times, but the ultimate source appears to be, according to Stephen Jay Gould, a description of Eohippus written by Henry Fairfield Osborn. It was Gould's opinion that Osborn was excited about the idea of a horse similar in size to a dog and that he was vague in his metaphors to fox hunting when describing the small horse Eohippus. Osborn's comparisons and metaphors make Eohippus out to be a 15 in tall 19 lb horse (the size of a Fox Terrier, obviously); however, Eohippus is approximately 24 inches tall and weighed approximately 50 lbs. There is a difference in the way these animals are measured as well; dogs and horses are both measured from the ground to their withers, the caudal aspect of the shoulders; however, horses typically have a little more soft tissue (muscle and/or fat depending on the breed of dog or horse) than dogs in this area. This is only a problem in comparing the two similarly sized animals in that Eohippus is lacking in the soft tissue area; either way it is still taller than a Fox Terrier. Unfortunately, this sizeable lie is the largest claim to fame, for most people, for Eohippus. It was, of course, also the first recognizable horse, making it an important fossil animal in the history of not only horses, but human beings and, arguably, a large portion of the globe and all of its life. For those more interested in the impact that the descendants of Eohippus have had on the world I recommend starting with this article from Khan Academy.

17 April 2018

The Ever Popular Shrunken Horse

If anyone has ever seen a documentary on the evolution of horses they have most likely seen or heard Bruce MacFadden. They may not have known it, but Dr. MacFadden has, for over 30 years now, been one of the premier horse evolution researchers in the world. Therefore, if one were to search for scientific articles on or mentioning Eohippus they could not, and certainly should not, be amazed when the first two results are MacFadden papers from the 1980s on the size of Eohippus and dental evolution using Eohippus as a vehicle for the discussion (and arguments for evolution based on horses too). There are more recent articles as well, of course, including Froelich's systematics paper on Eocene horses and even a description of museum mounted specimens by G. G. Simpson from 1932 (we all know by now I love reading older scientific articles so of course there was going to be at least one!).

16 April 2018

Prancing Forest Pony

Coursera is a website that has many free courses from different sources, including a number of universities. One course, on horse care, has a video detailing some of the finer points of horse evolution. This video discusses Eohippus and other early horses, so it is a good starting point for any day with a number of videos on early horses. Aside from this, Eohippus is not much of a screen start. The small horses did have one "starring" role in the 1969 movie Valley of Gwangi. Built by Ray Harryhausen, the small model horses were far smaller than they would have been in real life, but they are still adorably stop-motion animated in great detail.

14 April 2018

Dawn of the Horses

©Charles R. Knight
Possibly the most synonymized taxon in the entirety of paleontology, Hyracotherium angustidens was named by E. D. Cope in 1875. In 1876 O. C. Marsh described a similar taxon, naming it Eohippus validus. When Clive Forster noted similarities between the genera in 1932 he reassigned E. validus to the senior genus Hyracotherium. When Hyracotherium was redescribed as a paraphyletic taxon in recent years it was noted that H. angustidens and H. validus were identical species, and Marsh's specific name was considered junior to Cope's, but was considered the only valid genus of the two. Therefore, after all of these taxonomic twists, the animal considered the earliest and smallest of the equid lineage was officially renamed Eohippus angustidens. The official list of synonyms for Eohippus stands at 13 junior names, 3 of which are actually subspecies of other synonyms. Regardless, the small horses are interesting in many ways and, more importantly, are animals that have not been discussed here in full, and are therefore deserving of some time in the spotlight.

12 April 2018

People Love Cats

Pseudaelurus may be the most important cat in the entire family line that almost no one has ever heard of. Aside from ending the North American "cat-gap," Pseudaelurus is an important genus because these cats represent the last common ancestors of a diverse array of cats and "near cats." Saber-tooth cats, as a general term, technically fall out of the family line to cats before true felids. As an evolutionary grade, a group of taxa united by shared morphology, Pseudaelurus contains both felids and the true saber-tooth cats (Machairodontinae). This is why Pseudalurus is referred to as the last common ancestor to both saber-tooths and felids; the term "saber-tooth cat" can be extremely confusing because of the true and false labels in addition to the phylogenetic maze of carnivorans in which they settle out. For more information, I encourage everyone to read these articles on false saber tooths at ThoughtCo and Prehistoric Wildlife.

The genus Pseudaelurus has been separated and lumped a number of times over the years. However, the most recent phylogenetic studies (Werdelin et al. 2010 and Piras et al. 2013) have split Pseudalurus over three lineages definitively (unless someone comes along in the future to lump them again). The new genera include Hyperailurictis, Styriofelis, and Miopanther. These each represent a distinct lineage leading to the extinct lineage of American Hyperailurictis felids and the Styriofelis/Miopanther group (including both the extinct lineage of European Styriofelis felids and the extant Felinae which includes domesticated and wild cats). The third lineage retained the name Pseudaelurus and led to the extinct Machairodontinae, the true saber-tooth cats.

10 April 2018

Papers That Are Fond of Cats

Pseudaelurus is important in all lineages of felidae because it is the last common ancestor of many different types of cats, but it is also important to people that know, love, and study cats because of this as well. Additionally, Pseudaelurus is the genus of cat that bridged the so-called "cat-gap" in North American fossil history. Tom Rothwell is a paleontologist that knows a lot about Pseudaelurus and the cat-gap. Rothwell has written papers on the phylogeny of Pseudaelurus cats in North America and he has described new species within the genus as well. There are other paleontologists writing papers about Pseudaelurus of course. Papers on Pseudaelurus can be found from as far back as at least 1954 and at least one article on dentition and the skull was written in the 1930s. However, new remains of Pseudaelurus species are described on a somewhat regular basis; clearly this was a genus that was very successful and must have been quite varied to have so many different species identified.