Birds and Thunder

©Nobu Tamura

In general, native peoples of both South and North America have a number of legends and mythologies describing giant flying animals. From the Thunder Bird (a generic term that encompasses a wide range of mythological figures from different tribes) to Tah-tah-kle'-ah (a race of cave dwelling "owl women" from Yakama lore) to Achiyalatopa (from Zuni folklore), native peoples have been influenced by the idea of giant birds flying across the sky. In some instances these are giant bird-men/women but regardless of the anthropomorphizing of giant birds, these legends could have been influenced by real living animals. One such giant flying bird has been discussed here before (See Pelagornis). Another giant bird, more often associated with the southern hemisphere but by no means entirely limited to that hemisphere, was Argentavis magnificens (Magnificent Argentinian/Silver Bird). Flying through the skies during the Late Miocene and known, at present at least, from only Argentina, Argentavis possessed a wingspan of approximately 6.07 m (19.9 ft) and 72 kg (159 lb) by the greatest estimates. This makes it the second largest flying bird ever known behind Pelagornis. In comparison to living birds, the largest wingspan is that of the Wandering Albatross at 3.65 m (12 ft) and the heaviest (sustained) flyer is the Kori Bustard at 11.4 kg (25.1 lb). At this size Argentavis must have flown much like Pelagornis; flapping powered flight may have gotten it airborne but thermal soaring would have been the most likely model for sustained flight.

Iconic Images

Probably the best Bison latifrons image I have seen this past week (before looking tonight as I write this sentence) is that of Davide Bonadonna that I shared on the Facebook version of this page. Rather than paste it in here without contacting Davide, I will link his gallery where he hosts his illustrations. A large majority of bison illustrations are not as exciting as Bonadonna's or include modern bison being attacked by wolves (if not a hunting scene with Native Americans. In the "non-action but still fun" category one of the best images I have seen this week is Christopher DiPiazza's B. latifrons at the watering hole. I think I like this image more because it shows an interesting level of curiosity not often associated with the big brutish bison and also because it has softer tones that contrast with a lot of the images we have looked at over the course of the week. Please feel free to share more illustrations that you like in the comments.

Documentaries Everywhere

I was considering what to do about the popular culture references today. There are a number of things that I could do, obviously, as we know that modern bison are something that the public is well aware of. I think, instead, that we should look at some documentaries which discuss the historical significance of bison as well as their current conservation status and situation. Though these documentaries do not specifically discuss the three species we have been discussing this week, the life history of extant bison is similar to that of their extinct family members and is therefore informative. The National Park Service covers a little history and their extant modern herds in the linked page. This second video, from the Kratt brothers (in their Wild Kratts series), may be a cartoon (mostly) but its appeal to the younger audience is not to be overlooked. The information that is given out in this video is useful, accurate, and does indeed go beyond it being a children's cartoon. There are also somewhat more traditional documentaries such as this "Fabulous Animals" show and Facing the Storm: the Story of the American Bison (which is movie length). I know that we are well away from extinct animals with these shows, but being able to see a modern descendant and how it lived on quite similar ground (ignoring the members of B. latifrons and B. antiquus found along the eastern seaboard) is important to trying to reconstruct the lives of the extinct animals.

Buffalo (Bison) Papers

Many descriptive papers have been published for Bison latifrons and B. antiquus. Bison occidentalis, however, does not have as many description papers published concerning its remains. There could be any number of reasons for this, but after looking over papers and fossil locations as well as the Paleobiology Database (PbDb: https://paleobiodb.org/navigator/#/a6d8c0b8) the major reason for this might be that some sources, at least, consider B. occidentalis to be a subjective synonym for B. antiquus. This means that the type of the two species is not a shared fossil and that the debate on their synonymy is open. Unresolved taxonomy like this can lead to some sources like the PbDbnot acknowledging the species as unique while others at the same time do still consider it a unique species, such as Hawley, et al. 2013 which describes the occurrence of B. occidentalis fossils throughout the Wisconsin and Minnesota.

The range of these species has always been an interesting topic for research descriptions and has proved fruitful as well. Representative ranges can be hypothesized for each with articles detailing discovery sites and discussing their significance to the ranges. For instance, B. latifrons has been described in South Dakota (see above), Kansas, Nebraska, and even Georgia. Bison antiquus has been described from remains found in Florida, Alberta, Canada (with a mention of B. occidentalis as well), Washington, and Southern California. Bison occidentalis has been described from sites in Iowa, Alberta, Canada, Texas, and California.

A lot of papers go beyond simple description of these three taxa. A large number of papers published about these papers are from archaeological journals, which is highly logical. Bison, regardless of species, have been some of, and eventually the absolute largest, herbivorous North American mammals encountered by humans. Their use as food, clothing, crafting sources, weapons, and fuel for fires is well documented in North American historical sources and from archaeological digs (as a reference read Agogino and Frankforter 1960 and Wheat 1967). Associations of bison with archaeology is to be expected and some of the articles detail not only interesting aspects of the animal's life histories (refer to this article on butchering and taphonomy as an example) but also a great deal about their capability to endure hardships both human inflicted and natural. These include descriptions of diseases that have been studied in B. antiquus as well the effects of hunting in B. occidentalis.

There are a lot of articles here today, but I cannot apologize for the rich literary record of bison research; nor would I want to if I was asked to honestly.

Three Sets of Information

My plan for this week is to, unlike other weeks, treat the three endemic species of North American bison as individual animals rather than discussing the genus as a single entity and pulling out interesting information regarding individual species. The reason we are approaching the information this way is because, other than overlap zones in the history of the genus, the three species are radically different morphologically and warrant their own attention as parts of the whole evolutionary history of the genus Bison. For a quick overview of fossil bison without reading the following paragraphs a short stop in the digital library of the San Diego Zoo may be all you need. To start, we will look at the three species in order of their history, meaning that B. latifrons is our first stop.

The artist Roman Uchytel is typically mentioned when we look at his illstrations and interpretations of paleofauna. Today, however, his art coincides includes a concise history of B. latifrons. His illustration, of course, is a nice addition to the information, but not the primary reason to follow this link to his website. Not to be outdone by the display shared yesterday from North Dakota, other states also have information on B. latifrons that were unearthed within their borders. Speaking to the range of the animal, there are also finds from San Diego and as far as Florida (B. antiquus is also mentioned on this site, attesting to its range as well) that are mentioned. This site shows and mentions the sale of fossils but such practices are not endorsed or encouraged here.

The intermediate species, B. occidentalis, also has space and information dedicated to it on Roman Uchytel's site. Again, his illustration is a positive bonus to the information provided. Most of the information is taken from Wikipedia, but that is not too important here. Bison occidentalis is not as well known as B. latifrons or B. antiquus, and most of the information online about this species is actually in the form of descriptive papers, which we will save for Tuesday.

As with the previous two species, B. antiquus has been illustrated by Roman Uchytel and he has paraphrased information from Wikipedia. Placing the three side by side is informative and interesting in its own right actually, so it might be worth the momentary effort. Bison antiquus has a few more resources online. This is partially due to its more recent history and of course to those resources being studied a little more in depth than the other fossil species. In addition to Florida and the western part of the North America, there are specimens of B. antiquus known from Ontario, Canada, Texas, and Florida.

November in North America

It is possible that if you are from North America you are aware of the trend in the last 20 or so years to take back holidays celebrating European domination of the native populations of this continent. I remember personally seeing protests at Thanksgiving parades in Plymouth and more and more states appear to be dropping Columbus Day as an official holiday or at least renaming it. Given that the United States of America observes a Thanksgiving event in this month, the same holiday as the protests just mentioned for anyone not following U. S. holidays, I thought it might be interesting to look at the fossil history of some of the groups of animals that have been of special importance to the native cultures that once spread across this continent and that we have, to a significant degree, lost over the past 400 years. This is a look into how the animals that became important to the peoples of North America became the animals that they are now and what their fossil history, regardless of how recent those are, reveals about their evolution. I know these are not dinosaurs, but life on Earth is complex and filled with a lot more than dinosaurs, so hold on for the ride, or take a break and come back to us in December. The first animal that we will look at this month is the America Bison.

The American Bison (Bison bison) has a long history that, like a significant number of animals, starts on another continent; there is an extant European Bison (Bison bonasus) distantly related to and far more rare than the American Bison. The fossils we are going to discuss are the members of the family that arrived or thrived in North America prior to the appearance of what we would recognizably call the American Bison. Three extinct species of the genus Bison were endemic to North America prior to the appearance of Bison bison, the American Bison, in the fossil record. These species were, in order, B. latifrons, B. occidentalis, and B. antiquus. They range from approximately 240,000 years ago when B. latifrons is thought to have initially crossed the Bering Land Bridge into North America to approximately 5,000 years ago when B. antiquus appears to have gone extinct. The three species are not identical and B. latifrons is actually quite impressive, measuring in at 2.5 meters (8.2 ft) and estimated to have tipped the scales at 2,000 kilograms (4,400 lb); that is almost as tall as a modern Asian Elephant. The horns of B. latifrons measured approximately 213 centimeters (84 in) from one tip to the other. Bison bison measures in with horns approximately 66 centimeters (26 in) from tip to tip. Bison occidentalis is less well-known, but it is smaller than B. latifrons and its horns, also much smaller, pointed toward the rear of its skull, rather than the front. Bison antiquus was nearly as tall at 2.27 m (7.5 ft) but much lighter at 1,588 kg (3500 lb) and with horns noticeably smaller, though pointing forward, that measured approximately 1 m (3 ft) wide.

Photo from North Dakota Department of Mineral Resources. B. latifrons exhibit at the North Dakota Heritage Center

All The Pictures

What is the absolute best illustration, scientific image, line drawing, or photograph of a fossil of Helicoprion? If you cannot think of an answer, you are not alone. Is it this image of the estimated size of Helicoprion? It might be this image of all of the hypothesized Helicoprion morphologies (I saved it for my own visual delight).  The Mary Parrish illustration shared on Wednesday is up on the list of good illustrations for most people. There are a number of poor illustrations; we will not share those here today. My personal favorite, as we always see here on Fridays (feel free to share your own of course, but I write it, I choose it typically). The thing this week is that I do not really have a favorite. Some of the best illustrations are outdated and terribly wrong, despite their wonderful appearance. Mary Parrish's interpretation is wonderful, and Nobu Tamura's is as well (see Saturday's image). The image for today, rather than being a favored illustration, is one of my favorite photographs of a Helicoprion fossil. This tooth whorl is immense in appearance and its rolling form is somewhat mesmerizing. I almost cannot stop looking at it honestly.

Other Anatomy

The papers yesterday described the anatomy of Helicoprion's tooth whorl and as such, though we usually pick the most interesting anatomy and describe it on Wednesdays, we will have to discuss something slightly different this Wednesday. The topic for today still has to do with the tooth whorl; it is actually almost impossible not to discuss the only two materials that are known from Helicoprion  fossils (crushed cartilage and dental remains). Two hundred ninety million years ago Helicoprion was a successful predator in oceans globally, but what was it eating with its strange tooth whorl? The tooth whorl, according to the Smithsonian reconstruction, was not the first line of attack for this shark, and that is something important to talk about in terms of diet. When the tooth whorl is placed in the older positions (in the front of the mouth, the middle of the mouth, as an extension of the chin) the scenes we saw in the Animal Planet clip make a lot of sense; Helicoprion slicing fish and squid in half furiously as it swims about in the ocean. The interpretation of Mary Parrish (with help from Robert Purdy, Victor Springer, and Matt Carrano) places the tooth whorl in the gullet of Helicoprion. This positioning places the whorl in the same area as the gills (consisting of five gills rather than six/seven as is common in basal extant sharks for the shark enthusiasts) but without blocking their ability to extract oxygen from the water. The solution to the tooth whorl being in the throat was not having to swallow food before being able to chew it or bite at it. Instead, this reconstruction possesses a set of teeth similar to those of other sharks; a cartilaginous jaw housing rows of teeth that are used for catching, injuring, and otherwise stopping prey from getting away. The teeth in the throat, then, could have been used to snag prey as it entered the oral cavity, with the more traditional teeth pulling the prey into the mouth and the tooth whorl pulling the prey into the throat. Extant animals such as some snakes, fish, and other reptiles as well as extinct animals like mosasaurs possess teeth on the palatal bones that act in a similar way, helping to hold and move prey further into the throat and down the esophagus than mandibular and maxillary teeth are capable of doing. This version of the purpose of the tooth whorl is practical, if not as fantastic as some of the past iterations of the curious anatomical hypotheses.

Papers for Halloween

Is there a better way to spend Halloween than reading papers about a fascinating and scary looking shark? There might be, but I am not going to tell you how to spend your evening. One could spend literally all night reading about Helicoprion; there is seriously that much literature out there on this very interesting shark. I will gladly pick out a few articles for everyone today though. First, I recommend reading both Chorn, et al. 1978 and Eastman 1900 for reviews of the early and more recent reviews of Helicoprion descriptions. Next, I would recommend reading Tapanila, et al. 2013. This study includes a CT image study of the tooth whorl and description of its anatomy and corrected placement in the mouth including a massive illustration of all of the hypothesized placements of the tooth whorl in recorded publications. Lastly, I suggest Ramsay, et al. 2015 which further explores Tapanila, et al.'s hypothesis, CT data, and compares Helicoprion with other genera of shark. This publication also discusses the overall morphology of the shark and how it went about using that tooth whorl in its daily life.

Prehistoric Terrors

Helicoprion has appeared in a number of documentaries and has been mentioned in a number of shows that do not really concern the intriguing shark. This short clip from Animal Planet's River Monsters is the best clip available online from any of the documentary mentions of Helicoprion. It is also the only clip online other than the Discovery Canada clip shared yesterday. As a bonus, one can see a photo of a 3D printed tooth whorl on the River Monsters website for the episode Prehistoric Terror here.

Scaring Children with Teeth

The teeth of Helicoprion can be somewhat frightening in a number of different ways. However, we should probably make sure that the kids in the audience are not frightened when they look at sites like Prehistoric Wildlife that showcase the teeth and the many different hypothesized alignments of those teeth over time. The number of alignments and positions of the teeth are actually somewhat amazing, all things considered; every idea that was put forth had those teeth in some interesting and new position in the body of the shark until their actual position was surmised in the last 50 years or so. In addition to the history of the teeth on Prehistoric Wildlife, there are a number of short informational videos and clips of longer documentaries from Discovery and Animal Planet that are worth checking out. This shorter clip from Discovery Canada goes well with the comprehensive fact page and leave us some other quality videos for tomorrow.

Fearsome Sharks

©Nobu Tamura, 2016; most recent accepted iteration of whorl location

Few animals are as frightening to humans, as primates, as large oceanic predators. The diversity of sharks is such that we could discuss almost any member of the shark family and have a "scary" animal for the final full week of October. What most anyone would imagine is the obvious choice for a scary shark would is something in the Carcharodon genus; that being the group that contains C. megalodon (Megalodon) as well as C. carcharias (Great white shark). Instead, because it is one of the most interesting of the odd members of the shark family tree, this week we will discuss the genus Helicoprion. Contrary to most popular knowledge, Helicoprion is not a single species, but rather a genus consisting of 3 acknowledged and accepted species and 3 questionable species. These species are: H. bessonowi Karpinsky, 1899; H. davisii Teichert, 1940; H. ergasaminon Bendix-Almgreen, 1966; ?H. karpinskii Obruchev, 1953; ?H. mexicanus Mullerried, 1945; and ?H. svalis Siedlecki, 1970. Helicoprion is better known as the "tooth whorl" shark, owing to their unique spiral arrangement of teeth. The shark is known from global deposits spanning North America, Europe, Asia, and Australia, but the cartilaginous elements of the skull, spine, and body are unknown because of their relative inability to fossilize well. The whorl of teeth was, because of a lack of associated material, at one time or another, thought to have been the nasal process, a throat structure, and teeth, of course, placed in different portions of the jaw. Different specimens are named from different regions and for having disparate tooth whorls; the only possible evidence for individual species given the lack of other skeletal elements for most of the specimens.

Iconic Representation

Deviant Paleoart via Creative Commons

As I have mentioned a few times this week, there are many illustrations of Majungasaurus out on the internet for people to view and be entertained by. There are many images of the dinosaur running, such as this one (though it is a bit skeletal). There are also interpretations of Majungasaurus roaring, which look quite frightening, to smaller dinosaurs, and is somewhat stereotypical, but nonetheless, classic subjects of illustration. This version of the mouth open posture is simply showing an interpreted gape and the rows of teeth Majungasaurus had in its mouth, which is nice to see and a nice inset to the main illustration. There is even am illustration on the National Science Foundation page detailing the hypothesized air sacs of Majungasaurus. These are all well done and worthy of note, but whenever I think of Majungasaurus there is one very specific illustration that always comes to mind. The image, shown here, is a specific view of the head of Majungasaurus in high detail. We could spend a day discussing, critiquing, and appreciating all of the illustrations here, but instead, as I am backdating this entry, we will move on shortly.

Majungasaurus Everywhere

Majungasaurus has been seen in many different forms of media for the past 60 years. Originally described by the French paleontologist Rene Lavocat in 1955, Majungasaurus was named as the dinosaur of the province it came from, Mahajanga in northwestern Madagascar. Lavocat's described remains were not the first remains described, but the 1896 description of theropod remains from Mahajanga were published as new remains of Megalosaurus by another French paleontologist, Charles Deperet. Given this extremely long history of remains, the amount of popular knowledge and subsequent popular culture references of Majungasaurusought to be much more extensive than it currently is, despite the mistaken name. Following the 1979 description of remains under the name Majungatholus atopus (Sues and Taquet) the dinosaur garnered more attention, as a pachycephalosaur, until its theropod and cannibalistic nature became more well known and widespread after the 1998 discovery of Majungatholus-like set of remains. Those remains were described and reassigned to Majungasaurus, with the name Majungatholus then synonymized with the older name.

Aside from the two documentaries shared earlier this week Majungasaurus has not appeared in many places on television or in movies. However, Majungasaurus has been illustrated many different ways by many different artists and has been written about many different times by many different authors. Majungasaurus appears in dinosaur encyclopedias aimed at kids, kids picture books, general dinosaur knowledge books, and even college level texts. Perhaps speaking even more to the popularity of Majungasaurus is the copious number of toys and models produced in different poses and from different molds.

Papers Everywhere

Being an ugly cannibal dinosaur has its perks. In the scientific community it has perks at least. The number of papers written about Majungasaurus (including its synonymous genus Majungatholus) is very respectable. The paper regarding cannibalism was shared the other day, though if you cannot find it through an institution of your own it is difficult to find online. I would share it if I had permission to do so, unfortunately it is not my paper. I can point out some other good topics that have been covered though.

The interesting anatomy of Majungasaurus is discussed in detail in a 184 page special memoir entirely dedicated to Majungasaurus crenatissimus published through the Journal of Vertebrate Paleontology in 2007. A number of different topics including the appendicular skeleton, phylogney, dentition, and observed pathologies are discussed in the memoir. Particularly interesting to myself is an article on the craniofacial anatomy. The craniofacial anatomy of Majungasaurus is a defining feature of the dinosaur and is covered in depth in the memoir as well. Majungasaurus is a dinosaur with a lot of bumps and nodules on its skull that cause it to look somewhat terrifying and rather interesting at the same time. These morphological oddities have been discussed in passing a number of times by a number of different authors but Sampson and Witmer tackled the topic head on in the memoir The paper discusses the anatomy of the skull in light of a then newly discovered cache of skull material. This entire publication can be found at this link on BioOne, though access to JVP articles is regulated and available to members only without paying for individual articles. I understand that this does not help anyone access the articles mentioned here if they are not members, but this is a one stop source for Majungasaurus information. Those without access can find a similarly populated list here, but please be aware that the list is 5 years old and some links may not work.

Cannibalism Imagined

Due to the highly publicized knowledge of cannibalism in Majungasaurus there have been multiple iterations of animated and illustrated versions of Majungasaurus engaging in cannibalism. As stated earlier in the week, the act of cannibalism is intriguing to many different people and that is why there are so many different interpretations. There are two different documentaries that have animated this behavior. The two documentaries independently portray active predatory situations wherein one Majungasaurus attacks and eats a second individual. This, as we stated before, is hypothesized and, while making for good television, is certainly not a guaranteed certainty. In the BBC documentary Planet Dinosaur the predatory cannibalism occurs when there is a shortage of food and two young animals are still hungry, prompting their mother to secure some kind of food for the young. The second, History's Jurassic Fight Club, approaches the subject in a similar manner. Instead, a solitary Majungasaurus eating a smaller dinosaur it has killed is confronted by another Majungasaurus looking to steal a meal. Fighting ensues and one of the animals ends up with two meals. The downfall of both documentaries is not in presenting hypothetical situations or imagining dinosaur fights (most dinosaur documentaries love doing these scenes) but instead in the fact that Majungasaurus was an abelisaurid and possessed very unique forelimbs and hands. The BBC version of the dinosaur is closer to the reconstructed skeleton, but is still a little wrong because the arms are still facing forward and in a "want to hug you" sort of posture.

Cannibalism on Display

How do we know an animal that is now a fossil was a cannibal? As with much evidence of cannibalism, even in extant animals, we must look at the teeth, the wounds, and how these two pieces of evidence are correlated. In the past, ichthyosaurs (specifically Shonisaurus and the ichnospecies Ichthyosaurolites) and Coelophysis were suggested to have been extremely cannibalistic in their behaviors. A little over 11 years ago, the cannibalistic tendencies of Coelophysis were analyzed and refuted; the supposedly cannibalized animasl turned out to be a basal crocodile and outside of the body of the second Coelophysis specimen accused. Ichthyosaurolites, on the other hand, is an ichnospecies based entirely on ichthyosaur coprolites that contain the skeletal remains of other ichthyosaurs; the name literally means "ichthyosaur coprolite (fossilized feces)".

From Rogers, et al. 2003. Caudal tail chevron of Majungasaurus. White arrows indicate drag marks and black arrows indicate impressions initial biting marks from Majungasaurus teeth.

In the skull of Majungasaurus, the teeth are characteristically shaped, spaced, and serrated. All of these identifiers have helped paleontologists to recognize the marks of Majungasaurus feeding on a number of other animals from Madagascar. Chief among the animals possessing numerous bite marks from Majungasaurus teeth are the sauropod Rapetosaurus and Majungasaurus itself. No other theropods are known from Madagascar during the 70 - 66 MYA time frame during which Majungasaurus is known to have lived. This was used as the first inference concerning the tooth marks on Majungasaurus bones. This in turn led Rogers, Krause, and Curry Rogers to look at the teeth of Majungasaurus and at the marks that they had left on Rapetosaurus bones in 2003; Curry Rogers had led the description of Rapetosaurus in 2001. The initial bite marks that we see (look at the black arrows) are spaced and shaped identically to the teeth known from the multiple Majungasaurus skulls that have been recovered. The drag marks (white arrows) indicae areas where the serrated denticles have been dragged across the bones.

The first argument that is made here, often, is that the results of interspecies combat might look something like this. However, there are two important aspects of these wounds that make the case for cannibalism more compelling. The first is that these wounds show no sign of healing; the bone would have likely attempted to heal itself, at least, a little, after a traumatic bite in which humerous teeth insulted and scratched the bone deeply enough to clearly score the skeletal material. The second is that these chevrons, and many other limb and vertebral elements that also contain bite marks like these, are inaccessible during combat as they are in areas that could only be (easily) bitten when other elements of the body were exposed either through decomposition or predation.

The remaining question, however, is whether this cannibalism occurred as a result of scavenging behaviors or if Majungasaurus actively hunted members of its own species. The two activities have been documented in various extant species including lions and chimpanzees, so neither would be exceptionally abnormal or unique to Majungasaurus. For more reading on the exact findings of the Rogers, et al. team, read the following paper:

Rogers, R.R.; Krause, D.W.; Rogers, K.C. (2003) “Cannibalism in the Madagascan dinosaur Majungatholus atopus.” Nature, Vol. 422, pp. 515-518

An Old Ugly Dinosaur

©Nobu Tamura

One thing that creeps into horror movies and the Halloween season every year is the act of cannibalism. There are cannibalistic animals throughout the animal world but it is a taboo in most human societies and that makes many of us cringe when we hear about cannibalism in animal groups. Dinosaur cannibalism is rarely documented, but one theropod is particularly well known for its cannibalistic behaviors. Majungasaurus crenatissimus was an abelisaurid theropod and the apex, and possibly only large, predator of Madagascar during Late Cretaceous. At the time Madagascar was already an island separated from both the Indian subcontinent and African continent. As the largest predator on the island Majungasaurus had only other members of its species to truly challenge its supremacy as a predator on the island. Whether these clashes led to the evidence of cannibalism or it was a result of scavenging we do not know. However, Majungasaurus' cannibalistic behaviors and its abelisaurid body plan and often craggy frightening skull morphology make this theropod one of the ugly and frightening fossil animals that deservedly we are discussing during October and during the week leading into the Halloween week.

Portrait of an Ugly Therapsid

One of the best things about very odd animals is that they tend to inspire a lot of interpretations and illustrations because they tend to spark the imagination. Estemmenosuchus certainly inspires fantastical illustrations; Dinocephalian fossils have a tendency to inspire fantastical illustrations because a number of them possess very intriguing and unique skulls. The reconstructed skeleton of Estemmenosuchus is equally intriguing; we will not look at illustrations only today however.

©Dmitry Bogdanov

It is important to note that the realistic nature of illustrations can be affected by the type of illustration we are looking at. Dmitry Bogdanov's style, like Nobu Tamura's, is very soft and often portrays the animal in sterile conditions on white backgrounds; this is not true for all of either artist's illustrations. However, this is not detrimental to the art and, in fact, the implied simplicity of the illustration of this Estemmenosuchus uralensis alows us to more thoroughly take in the entire animal and appreciate the posture, the size of the head, and the stout character of the overall animal. Estemmenosuchus, as we knew before seeing the animal as portrayed here, was a sprawling and squat animal with large canine teeth, which are very visible here. This illustration is labeled as a male animal. The largest canines are used as evidence to support hypotheses of sexual dimorphism in Estemmenosuchus in at least one paper.

©Vladimir Nikolov

More realistic appearances of Estemmenosuchus are as reliant on a stark and bold illustration style as the first is on a softer and cooler colored style. These are most realized in the line drawings that accompany the description papers, but can also be found in the styles of artists like Raul Martin, Dinoraul, and Walter Myers. The illustration included here as a representative of the more realistic appearing (because of its hard lines and high contrast as well as lack of soft tones) was drawn by Vladimir Nikolov. The description of this piece by the artist states that the scene depicts two male members of the genus are engaged in territorial combat. The fierce looking faces and skulls of the animals were apparently not enough to warn one another off from actual physical fighting, as we see in many extant species today.

Sprawling Horned Faces

From Chudinov 1965

Estemmenosuchus has a crown of horns. The crown of horns has been hypothesized to have been used for intraspecific signalling and display short of combat; combat with the horns was probably used as an absolute last resort by these animals. The reason that it would have been used as a last resort is that the horns were massive bone structures. Unlike antlers, horns are composed of bone and insult or injury to these structures can be much more traumatic to the animals than damage to antlers (injuries to antlers are serious of course though). The horns of Estemmenosuchus were composed of extremely thick outgrowths of the frontals and cause the skull to appear even more massive than it is. Known skulls of Estemmenosuchus are approximately 65 cm (26 in) in length. That is not the only thing that is large and unique about Estemmenosuchus though. This large therapsid (approximately 3 m  or 10 ft long) also had a sprawling posture; this is somewhat typical in therapsids and Permian reptiles as well. Some have used this sprawling posture as evidence for an herbivorous diet, saying that the sprawling posture enabled the animal to hold a large fermenting gut with more support than if it had a posture like cattle or a similar mammal; this seems less than ideal given what we know about extant mammals. The canines of Estemmenosuchus are used as evidence to a different, more omnivorous but not quite carnivorous, dietary regimen.