Second of the Proto-Cats

April 7, 2018, 7:34 pm

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The first of the felids was known as Proailurus. The next most recent descendant is a group of cats known as Pseudaelurus. The genus Pseudaelurus is the last common ancestor of extant felines (mostly small to medium cats, including domestic breeds), pantherines (medium to large cats including lions, tigers, and leopards), and machairodonts (extinct saber-tooth cats). Pseudaelurus consists of twelve accepted species. Originating in Eurasia, species of Pseudaelurus migrated across land bridges into North America, ending what is casually known as the "Cat-gap" from 25 to 18.5 million years ago when few, if any, cat fossils were found.

Figure 3.1 from Evolutionary Dynamics ©IOP Publishing LTD

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Cat Videos

April 8, 2018, 9:00 am

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The internet, it has been said, was built for cat videos. We all know that there is some truth to that statement. The internet is less built for cats as old as species of Pseudaelurus. There are videos on how cats became house pets that can stand in for some of the fact videos we are looking for, but they are just a stand in of course. There is also a German video that presents the facts that we would normally look for in a video. It is a good fact video, if you understand German.

Papers That Are Fond of Cats

April 10, 2018, 2:16 pm

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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.

People Love Cats

April 12, 2018, 5:50 pm

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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.

Dawn of the Horses

April 14, 2018, 9:19 pm

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©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.

Prancing Forest Pony

April 16, 2018, 6:48 pm

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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.

The Ever Popular Shrunken Horse

April 17, 2018, 8:34 pm

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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!).

Not So Tiny

April 19, 2018, 5:57 pm

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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.

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Pets Everywhere

April 21, 2018, 8:28 pm

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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.

Evolving Swine

April 22, 2018, 5:49 pm

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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.

Back to Dinosaurs

April 28, 2018, 8:28 pm

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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, Minotaurasaurusramachandrani, 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 TamuraCC BY 3.0

Possible Issues

April 29, 2018, 6:58 pm

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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.

Two Sides to Read

May 1, 2018, 8:02 pm

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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.

The Scary Face

May 4, 2018, 8:48 am

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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.

Favorite Oldies

May 6, 2018, 3:04 pm

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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.

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Facts and Movies

May 7, 2018, 6:45 pm

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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."

Balancing Papers on Horns

May 8, 2018, 8:10 pm

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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.

Ceratosaurus Anatomy

May 10, 2018, 9:22 am

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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 CommonsCC0 license

Small Stegosaurs

May 13, 2018, 5:32 pm

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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:

Fun to Type

May 14, 2018, 3:52 pm

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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.