STL Science Center

STL Science Center

31 March 2016

Toys and Games

There are more mentions of Lambeosaurus in games and toys than there are in any other popular media of any sort. They appear in books from time to time and documentaries even more frequently, but their appearance as toys far outpaces either of these other two pop culture modes of expression. To share just how prevalent Lambeosaurus is as a toy, consider these videos:
Also consider the fact that Lambeosaurus has appeared in fewer documentaries than many other hadrosaurs, but when it does, it is often not named. This gives the appearance of fewer Lambeosaurus documentaries but only the appearance; there are far more Lambeosaurus mentions in science based documentaries than people realize. This is also the case for mural sized artwork such as this:
© Julius Csotonyi

30 March 2016

Crest Conundrum

Adapted from Nobu Tamura
Crests (and sails) are perplexing in a vast array of taxa. In dinosaurs the existence of any kind of crest divides and destroys goodwill toward other scientists in some cricles but thankfully that is not a typically common occurrence. Crests tend to be a haven for so-called "arm-waving science" in which people speculate (often wildly) about scientific conclusions that require a significant suspension of disbelief with rather little evidence to infer from. In discussing the crests of Lambeosaurus, speculation and ridicule of speculators should be kept to a minimum, and will be done here. Bear in mind, though, that many strange assertions have been made regarding these crests, their functions, and why there are different shapes represented in the genus. Shape variation can be explained by differences in species within the genus as well as ontogeny; shapes of crests have been shown to change in individuals over the course of their lives in many different animals, living and fossil. Variations in shape that cannot be explained by ontogeny or species differences entirely may be explained by many other purposes. These include dimorphism where males and females exhibit different shapes and styles of crest. These could be indicative of vocal differences between the sexes as well as differences in visual signalling that requires the use of the crest. These purposes are all often cited as fact and are commonly accepted as such in documentaries and other popular outlets. In general, the shape of the crests is vaguely similar across species and ontogeny within lambeosaurines, including Lambeosaurus. The general shape includes  high vaulted anterior/rostral portion of the crest and, later in ontogeny it appears, that there is a longer posterior/caudal part of the crest that extends over the back portion of the skull. A few recreations and illustrations have made the back end of the crest appear to be flush with the posterior portion of the skull. Most of the ontogeny series abandons this flush look after juveniles grew into adulthood

29 March 2016

The Papers Remain Similar

Lambeosaurus has not been a hot topic in recent studies. The reason is not that Lambeosaurus has been entirely researched and figured out. Instead, Lambeosaurus has simply not been a big player in recent research. Hadrosaurs are very interesting creatures but are not so interesting that they are heavily researched in a multitude of lab groups. Even if they were, there are a lot of different hadrosaurs in the fossil record and Lambeosaurus is just one of those many taxa. The papers and research that has been done on Lambeosaurus in the time since the dinosaur was initially discovered are extensive and cover a variety of topics. There are always simple descriptions of remains that are published as they are discovered. The remains in question here are some of the newest remains that have been recovered, relatively considering the history of Lambeosaurus. Descriptions often lead to systematic reviews, such as that by Ostrom which lead to the reassignment of Hadrosaurus paucidens as Lambeosaurus paucidens. In order to discuss systematics and to adequately describe the dinosaur there need to be papers on the anatomy of the dinosaur as well. Luckily for everyone here, those papers also explicitly exist concerning the anatomy, specifically, of Lambeosaurus. Many times we have to make do with a similar animal, but having a description of the anatomy of the animal in question is very fortunate. Putting all three of these topics together we can then delve into more specific anatomical questions such as craniofacial ontogeny and even postcranial locomotor studies (we do not study those sorts of things in our lab so much, but they are interesting topics and fun to consider and important to understand).

28 March 2016

Movies Arrive

Since 2011 (the last time we covered Lambeosaurus) a lot of short videos and tribute slideshows have been put together for Lambeosaurus and posted online.  The majority of these are newer videos are groups of photos put together over irrelevant music; the assumption I hold here is that the music is like by the person that put the video together and they have no real thought other than that behind the coupling of a dinosaur they like and music that they choose. These include videos like the one posted directly below here.
I hope to find someone some day that will make more insightful choices with their pairing of dinosaurs and music. Until then we will have to be happy with the fact that in addition to these music slideshows there also exist educational videos. These videos are not entirely limited to English language videos, as many dinosaur videos tend to be. This video is narrated and describe in Spanish which appears to be the second most likely language of educational videos on the internet (definitely a personal observation with no real scientific basis behind it).
Aside from videos like these, the most popular videos of Lambeosaurus are based on toy reviews of many different company's Lambeosaurus models. We will look at some of these on Wednesday when we look at the different types of crests that have been attributed to different species of Lambeosaurus.

27 March 2016

Learning About Lambeosaurs

Lambeosaurus, as a genus, is a well known group of dinosaurs and has been well represented online in kid-friendly venues since there were dinosaur pages on the internet. There have been Lambeosaurus books, documentaries, and educational toys since long before the internet. Lambeosaurus has been a very popular dinosaur for a very long time, nearly a full century actually. The last post of Lambeosaurus facts (we have covered this dinosaur before, but back then there were very few links online) was very short and consisted of only a few short links and videos. Instead of posting simply the end of the Dinosaur Train episode in which Lambeosaurus appears, the entire episode can be seen on YouTube now.
Some of the pages that have been generated since the last Lambeosaurus fact day are not the greatest fact pages that exist, but they are helpful. The links found on the old post are still good. Sites like Dinosaur Jungle have increased the number of sites we see for Lambeosaurus. They do have an image that looks vaguely like a kangaroo though. Most of those facts are contained on the images of the fact trading cards shown below however.

26 March 2016

Back and Changing

I am altering the schedule of posts a very slight amount from the normal schedule. Instead of starting every week on Friday, from now on we will end our weeks on Friday. The day had only been the starting point prior to now because the first post had been on a Friday. The way the weeks are set up on the calendar a day like Saturday, Sunday, or Monday makes more sense as a starting point. We are going to go with Saturday here at Dinosaur of the Week because the start of the weekend is a good place to start your dinosaur fix of the week!

This week is the last full week of March. The last week of the month is the Brynn Metheney calendar week. This week's dinosaur, and March's calendar dinosaur, is the large crested herbivore Lambeosaurus. Lambeosaurus is named after the prolific Canadian paleontologist Lawrence Lambe. The material of the type species, Lambeosaurus lambei Parks 1923, was discovered and recovered by Lambe in 1903 and described and named by William Parks in 1923. Charles Sternberg described a second species that is still recognized, L. magnicristatus, in 1935 and a third species was added in 1964 by John Ostrom who reassigned Hadrosaurus paucidens Marsh 1889 as the material was inconclusive as Hadrosaurus and more closely resembled Lambeosaurus. The distinctive features of the genus Lambeosaurus include the large hadrosaurine body in addition to a head crest that acted as a resonating chamber and potentially as a space that could aid in regulating the temperatures of air entering and leaving the body. This may not be important for Brynn Metheney's astronaut version of the dinosaur, but in an environment with any type of variation in atmospheric temperature, the regulation of respired air was, and is, important to endothermic organisms.
©Brynn Metheney

23 March 2016

Types of Fossils

The type species, Chalicotherium goldfussi, is known from the Miocene and Pliocene of Europe. Factoring in the Late Oligocene fossils that are attributed to other species, Chalicotherium can be said to have existed for a rather long time, as far as giant mammals are concerned. This is said considering that the "typical" species exists for somewhere between 5 - 10 million years given accepted extinction rates but there are certainly outliers on both ends of that spectrum. The total time in the fossil record for which we know of Chalicotherium fossils totals approximately 24 million years (28.4 - 3.6 mya); clearly this genus could potentially represent an outlier from the accepted generalization. The type species is from the Upper Miocene of Germany (around 12 - 5.4 mya) and is estimated to be approximately 1500 kg and 2.6 m tall at the shoulder. The other two species are similarly sized and were initially known from around a contemporaneous geological era. Chalicotherium salinum was originally known from the Lower Pliocene (5.3 - 3.6 mya) in Pakistan and India also making it the youngest of the Chalicotherium species. All of these species are extremely large and were highly adapted for herbivory; gigantic herbivores is a commonly reoccurring theme in the history of life. Some of these adaptations include the horse-like head with a muscular set of lips capable of grasping vegetation and taking it into the mouth. The apparent loss of the incisors and canines throughout ontogeny has been linked to this cropping action in that the muscular lips are hypothesized to have worked against the resulting gumline to successfully crop vegetation more efficiently than the canines and incisors. The remaining teeth were molars that were squared in appearance. These teeth possessed low crowns suited for grinding vegetation passed back by the tongue from the muscular lips and gumlines.

While doing all of this processing and cropping of leaves, Chalicotherium did an extensive amount of lounging about and loitering. That loitering is preserved in callouses on the ischium where all of the weight of the mammal was situated as it sat under trees eating and processing. We can kind of think of Chalicotherium in terms of modern pandas and sloths.
Museu Geològic del Seminari de Barcelona

22 March 2016

A Wisened Beast

The gravel beasts are well studied. The fossil history of Chalicotherium is well known across two continents and has been well known for nearly two centuries now. In that time many papers have been written ranging from simple anatomical descriptions (sometimes in their native languages because they are older) to complex ecological descriptions. New Chalicotherium material is still recovered in places like Mongolia and China but so far these new discoveries have not led to any all encompassing studies beyond description that I have found online. There are a few older papers on biomechanics of the vertebral column that reference Chalicotherium in passing, as there should be given the extreme curvature of the vertebral column that is often depicted in mounted skeletons and illustrations. Curvature of this animal's spinal column is actually quite intriguing and, despite following the normal quadrupedal arching theme of vertebral columns, appears to be exaggerated. Although we are a little let down in that study not discussing Chalicotherium more we can always be sure, with mammals, that we will have more than enough biomechanics and wear patterns of teeth to read about. This is not a negative, it just happens that mammalian teeth, no unlike dinosaur teeth, are pervasive in the fossil record and many studies have been conducted using teeth to examine enamel, wear patterns, and many other topics.

21 March 2016

Giant Beasts and Video Games

Chalicotherium appears in many different kinds of videos because it is a very popular giant mammal. The more radical the animal the more likely it is that the animal will be shown in documentaries or movies and modeled in video games and other venues. The number of videos from the game ARK overloads the search for Chalicotherium, making it difficult to find videos from the Walking With Series and any other documentary that might happen to exist. ARK is a survival game set in various prehistoric eras that overlap; the setting is a made up world filled with dinosaurs, prehistoric mammals, and even hostile human players. The game has been in development for a few years and beta testing has allowed us to see animals like Chalicotherium for a while; the game is set for official release in June of this year. The videos of Chalicotherium from ARK, like that below, are mostly narrated by players and enthusiasts of the games.

The Walking With Series is much more entertainment than it is documentary; however, there is a respectable amount of science behind the series even when the entertainment is more pertinent than that science in an episode or portion of an episode. The episode of Walking With Beasts that features Chalicotherium is still online; BBC does tend to take these down when they can find them, so if you have not seen this episode and are interested I urge you to watch it as soon as possible. The episode is centered around the life story of an Indricotherium but does have a sizable (pun intended) portion showing Chalicotherium.

20 March 2016

Kids and A Giant Everything Mammal

Chalicotherium has convergent characteristics with a large suite of extant mammals that have taken over many different niches that were not necessarily occupied by Chalicotherium or any of its contemporaries; the world is not exactly the same as it was then and some of those niches may not have even existed at that time. These are not, though, the topics presented in most of the fact files. The sites do mention the convergent evolution, just not always the the extant analogies. The best site for all around discussion of Chalicotherium is About which does make mention of gorillas. Prehistoric Wildlife presents a little more in depth information, but is still not exhaustively comprehensive. The best thing about the site is that it presents some of the same information at a slightly higher reading level. The most simplistic, but still filled with facts, of all of the sites available is the site that is associated with the Walking With Series in which Chalicotherium features in the "ice age" series. A number of the facts are also present on this handy little image/trading card:

19 March 2016

The Skeleton Game

There are a lot of skeletons of Chalicotherium on display in many different museums across Europe. The prominence of the fossils within the entirety of Eurasia is what led to the massive amounts of skeletal material that is on display in those museums. The fact that all the species are massive and have very unique morphologies helps to make those mounted skeletons key pieces of the museum displays as well. Nothing attracts museum goers like massive oddities of the fossil world. This image of a skeleton in an browsing posture is informative as well as nicely done. Though the soft tissue is absent and therefore not highly informative to us as such, but seeing how the articulated skeleton would be situated in a common behavioral situation is actually highly informative. This image is actually based on the skeleton of another genus within the Chalicotherian family known as Anisodon. The two genera are very similar with one major exception existing in the forelimb digits of Chalicotherium which actually have long ungals, or claws, on the end of each distal phalanx. These most likely caused Chalicotherium to walk on its knuckles when bearing weight on its forelimbs. Due to the size of the animal its knuckle walking was a common practice. However, the claws were extremely useful to the animal (why else have them afterall?) as defensive tools. The claws were not agile or dexterous enough to be used for stripping leaves. Instead, the pictured behavioral posture above was probably a typical sight at the forest edges of the Miocene as these massive herbivores browsed the branches.

18 March 2016

Digging Into Mammals

The "gravel beasts" of the Oligocene and Pliocene are a bit of a skip from our normal fare here. Now and again we drop into the mammal-centric era of the Quaternary Period. The animals we find there are truly unique and bizarre. Some of the most unique, of course, are the gravel beasts, or the Chalicotheria. In particular this week is going to center on a single genus within the family: Chalicotherium. There are three recognized species of the enormous herbivorous browsing perissodactyls (odd-toe ungulates): Chalicotherium goldfussi Kaup, 1833; Chalicotherium salinum Forster-Cooper 1922; and Chalicotherium brevirostris Colbert 1934. Discovered throughout all of Eurasia regularly during the 19th and early 20th centuries, the first fossil was described by Johann Jakob Kaup in 1833 and originated in Miocene beds strata of Germany. The most intriguing elements of Chalicotherium species are the amalgam of characteristics that are seen together in this extremely tall and weird fossil mammal. These characteristics include horse-like heads, stout hindlimbs, and sloth-like forelimbs.

17 March 2016

Prestosuchus In Our Minds

Prestosuchus was a beastly Rauisuchian. Reminiscent of a bulldog type body plan in many ways and crocodilian in many others, the strange archosaur has caught the imagination and attentions of many fossil enthusiasts for a wide variety of reasons. This has led to a significant collection of literature and appearances of the archosaur in books, multiple illustrations, and a variety of different roles in documentaries. Some of these roles have not been outright portrayal, but discussion as a member of a very important group of animals early in archosaur evolution as well as being in a position along the trunk of a the tree of an extant group of animals has caused Prestosuchus to be a very well followed animal. Perhaps the reason that Prestosuchus is as popular as it is has to do with the fact that it is often portrayed as a terrestrial crocodile of the Triassic, but I am personally of the opinion that, all reasons above aside, Prestosuchus is popular because we have a rather robust history of study of the organism. Also, it is a large crocodile-esque animal that was capable of eating dinosaurs; small and early dinosaurs, but anything eating dinosaurs tends to amaze people because of the perceptions tied to the title "dinosaur".

16 March 2016

Rauisuchian Bulldog

Prestosuchus had a skull that was deep and stout. Relatively long and filled with teeth, the body caudal to that skull was long and gracile in comparison to large archosaurs that would come after it, but strong and robust compared to most of its contemporaries, especially its prey items. Give that Prestosuchus had a strong body that was built much more like a wrestler than a runner, the hypothesized niche of Prestosuchus has been described as that of an ambush predator of large prey items in particular. This makes sense considering that Prestosuchus was the largest of the Rauisuchians, supposedly, with the exception of Saurosuchus. Because it was so large in comparison with many of its contemporaries, including the fledgling groups of dinosaurs, Prestosuchus was highly likely to take large prey, defend it, and eat as much as it wanted prior to abandoning it completely to scavengers. That sort of hypothesized behavior can be seen in the image below.
(C) Maurílio Oliveira

15 March 2016

The Missing 1940's

Prestosuchus was named by well known German paleontologist Friedrich von Huene in 1942. He discovered the fossil near Sao Pedro do Sul in Brazil in 1938, thus explaining how a German scientist was able to name a fossil from half a world away during the height of World War II in Europe. Von Huene named the genus for Brazilian paleontologist Vincento Prestes de Almeida who was a self taught scientist. The paper initially describing Prestosuchus does not appear online and the first paper recording the name at all in the Biodiversity Heritage Library is from 1957 (it is mentioned in an article on Triassic footprints in New Jersey). More modern papers do exist and are more entertaining for our purposes though. These include a discussion of the braincase from Mastrantonio et al. (2013) that uses the complete braincase to assess phylogenetic relationships with other Rauisuchians and archosaurs in general. The paper concludes that there are still phylogenetic issues to be worked out but that Rauisuchians are closer to crocodylomorphs than they are to aetosaurs and phytosaurs. Liparini and Schultz (2013) move away from the brain to discuss the muscles of the thigh that appeared to be rather unique. One of the reasons that the thigh muscles in particular were important in discussions of locomotion of Prestosuchus is that the same muscles in Poposaurus, which is a bipedal pseudosuchian archosaur, were very well adapted for bipedality by being shortened despite having the same general arrangement of pillar-erect gait as other pseudosuchian and Rauisuchian animals. There are a number of other papers (Prestosuchus is very well studied and written on) but these two are plenty for one day as they are rather in depth.

Today's papers:
Alexandre Liparini and Cesar Leandro Schultz A reconstruction of the thigh musculature of the extinct pseudosuchian Prestosuchus chiniquensis from the Dinodontosaurus assemblage zone (Middle Triassic Epoch), Santa Maria 1 Sequence, southern Brazil (in Anatomy, phylogeny and palaeobiology of early archosaurs and their kin ) Special Publication - Geological Society of London (June 2013), 379(1):441-468

Bianca Martins Mastrantonio, Cesar L. Schultz, Julia B. Desojo and Juliana Bittencourt Garcia The braincase of Prestosuchus chiniquensis (Archosauria, Suchia) (in Anatomy, phylogeny and palaeobiology of early archosaurs and their kin ) Special Publication - Geological Society of London (April 2013), 379(1):425-440

14 March 2016

In Motion

Prestosuchus does not have videos regular videos associated with the archosaur. There are a few lower end fact "movies" that are not much more than slideshows, but these are encouraged even if they are not entirely useful for our purposes. There are even Vines with Prestosuchus. The point of Vine is beyond me; maybe I'm too old or maybe they were just the precursor to Apple's "moving pictures" (that is called a video Apple, we are not all gullible), but they can be useful for short introductions to a Prestosuchus skeleton, as that particular one is. The lack of narration is fine, but shorts like that with narration are also generally useful, such as this one.

13 March 2016

Kids and Almost Crocodiles

Photo by Ryan Hadley
There are a lot of websites that discuss Prestosuchus as a crocodile. The intricacies of phylogenetics and cladistics aside, we know that Prestosuchus is not properly a crocodile. Mentions in some BBC series websites completely ignore proper cladistics whereas more well attuned and informed websites like About (thankfully Bob Strauss has a strong attention to proper details) address the placement of Prestosuchus more appropriately. LiveScience also discusses Prestosuchus appropriately from a tree thinking mode of thought. However, the LiveScience page is more concerned with the Triassic as a whole and barely discusses the animal itself. Prestosuchus is very popular as a museum piece as well. This sort of popularity teaches kids about fossil animals of all kinds better than any website and better than can be done here some times as well.

12 March 2016

Not a Dragon

(C) Dmitry Bogdanov
The general appearance of Prestosuchus can be argued based on the type of scientific illustration that one deems appropriate. In the past, and we have discussed this here, the typical images that were produced were images in which the skin appeared to conform and mold almost directly to the skeleton of the fossil animal. This approach is not always realistic (some aspects of some animals can appear as though skin is stretched tautly over the skeleton) and leads to the appearance of animals that look as though they have been starved and lost much of their muscle mass. When this type of technique is applied to Prestosuchus the stunning similarity, through the interpretation of the artist, to a tyrannosaurid skull is very evident. Our knowledge of the skulls and heads of tyrannosaurids allows us to safely assert that their skulls are not covered by tautly stretched skin-on-skeleton as they have massive muscles under the surface of the skin. The similarity between the two skulls is not perfect and here appears somewhat exaggerated, but the resemblance does exist. The neck, abdomen, and tail of this Prestosuchus do not appear to be wanting in terms of nutrition as the head does, which leads us to think that the artist pulled the skin tightly on the head to accentuate the tyrannosaurid features of the skull.

(C) Nobu Tamura
An alternative approach to taut skin or well muscled head is to have a little of both. This approach presents us with a lesser look of emaciation. The overall look of the body in this depiction is much more crocodilian than the previous illustration, which appears much more lizard-like. Despite basal muscular evidence that places Prestosuchus in an early position, the likelihood of crocodilian scuting along the back is not necessarily difficult to accept. The somewhat crocodilian interpretation of the skin on the skull may also not be difficult to accept. The caveat in interpreting a distant ancestor as possessing many phenotypically similar character attributes as extant animals is that there are a large number of changes that will still take place between Prestosuchus and modern crocodiles and alligators. Many of these are obviously not present in either image, including the flattened tail for swimming and high placed nostrils for breathing while submerged. Most telling, of course, is the posture of Prestosuchus in comparison to modern crocodiles. The hips of Prestosuchus are constructed such that the legs are erect under the body forming a "pillar-erect" stance. Crocodiles on the other hand have a sprawling posture. The hips of Prestosuchus are rotated to accommodate this orientation in a way that is different from the hip joints of crocodiles.

11 March 2016

Difficulty in Ancestry

The skulls of some animals are strangely similar to animals that they are exceedingly distantly related to. We can understand the similarities in the context of convergent evolution; animals that require extreme biting forces develop similarly strong muscles and similarly shaped skulls to house the attachments of those muscles. Generally we only discuss the morphologies as how they occur and are similar and not the time at which they occur, geologically speaking. Therefore, we can discuss how an animal like Prestosuchus chiniquensis living in the Triassic of Brazil has a skull that looks considerably like that of a Cretaceous tyrannosaurid. Prestosuchus is only related to tyrannosaurs in that they are both archosaurs as the dinosaurs, and therefore tyrannosaurids, diverged from the early suchians, ancestors of modern crocodilians. The skulls of tyrannosaurids and Prestosuchus are deep and filled with large serrated teeth and have been mistaken for one another many times because of their similarities. The skull of Prestosuchus is not as air filled and lightweight (relative to size) as a tyrannosaurid skull, however. Skulls of Prestosuchus are clearly strong and beginning to show some of the solidifying characteristics of its descendants. Prestosuchus as a genus belongs nestled with Rauisuchia (by some accounts a wastebin group), a group of early Triassic archosaurs within Pseudosuchia that contains some fierce looking reptiles that, unlike their descendants, stood with a specialized erect posture and were definitely much more terrestrial than their descendants would eventually become.
AMNH, photo by Vince Smith

10 March 2016

Popularity and the Plated Dinosaur

Stegosaurus is popular because it was one of the first widely known North American dinosaurs with highly complete skeletons. Having very interesting anatomy always helps dinosaurs to become very well known also. Stegosaurus has appeared in many of the avenues of popular culture that we think of when we are trying to find out how popular dinosaurs are (this may just be myself as I write about the popularity of a given dinosaur every week). There are kids books and television shows and there are documentaries and movies. Stegosaurus has appeared in video games and even as wine bottle holders. The fact that we see Stegosaurus, as a genus, everywhere is tied directly to its prominence as one of the big recognizable symbols of dinosaur life. That set of dinosaurs includes the dinosaurs that I once got on a birthday cake: Stegosaurus, Triceratops, a sauropod often labeled Brontosaurus (even now), and Tyrannosaurus.

09 March 2016

Herbivorous Tanks

Many herbivorous animals have extensively large guts. Herbivores that do not have very large guts often have gizzards (chickens and ostriches) or simply do not efficiently digest all of the vegetable matter that they eat. Think of horses and their kin when you think of marginally efficient digestors; they often have rather whole vegetable manner in their feces. Obviously equids are not the worst animals when it comes to digestion, but they do not have the enormous guts that dinosaurs like Stegosaurus had. Stegosaurus stenops, as the largest species, most likely had the longest gut, though we cannot be certain that it was the widest gut. The small head of Stegosaurus was built for clipping and grinding vegetation for days without ending. The life of Stegosaurus was most likely dedicated to eating, not being eaten, and occasionally mating. The mating part of their life may have even included some raising of young, though the extent of hatchling rearing for Stegosaurus is not known. Juvenile stegosaurs are known from many fossil remains, but the youngest animals are missing from the records, for the most part. A hypothesized family group can be seen in the second Jurassic Park movie (The Lost World) and the idea of the small family group makes more sense than a multiple clutch of young creating a small herd. A sizable herd of any kind of stegosaurs would have been difficult for most predators to deal with as a single adult was difficult for most predators.

The spikes on the end of the tail were significantly dangerous to predators and other herbivorous dinosaurs alike. Officially called the Thagomizer (after the late Thag Simmons), the set of spikes varied by individual and species with S. sulcatus possessing distinctly larger spikes than the other two species. The tail and hypothesized maneuverability of the rear end of Stegosaurus would make for a deadly combination. It has been stated, by Bakker in The Dinosaur Heresies, that the hindlimbs could have been anchored and used as a stable platform while the rear end of Stegosaurus was rotated with significant force if not accuracy. This hypothesized action has been applied to a documentary in which a couple of stegosaurs caught in mud attempt to fight off ceratosaur and allosaur attackers. The point is that the rear end of the dinosaur is shown moving about in the highly mobile and strong manner described. It is much more likely that the tail end of Stegosaurus was mobile and useful as a defensive and offensive weapon than as a passive deterrent incapable of being whipped around as an attacking weapon.

08 March 2016

Plates For Heating

The plates on the back of Stegosaurus were not necessarily for heating or cooling, although that is one credible hypothesis. That sort of hypothesis was very popular for all animals with any kind of sail or large area of potentially highly vascularized tissue for a very long time. During the years just prior to the "rediscovery" of the older hypothesis of warm bloodedness in dinosaurs (see The Dinosaur Heresies for the backstory on the endotherm-ectotherm-endotherm history of hypotheses) the hypotheses of ectothermic blood heating using plates and sails was widely published upon by many authors. These include papers by Marsh describing the restoration of Stegosaurus (describing all three species); Farlow, Thompson and Rosner (1976) which considers heat loss; and Farlow, Hayashi, and Tattersall (2010) which discusses vascularization of the plates. The last paper is much more current than the first two, but it does still discuss the plates and their vascularization. Farlow is very serious about his Stegosaurus plates, and that level of commitment is quite commendable. Also, after almost 50 years the idea that we still have much to learn about the plates on the back of a dinosaur is quite amazing as well. The classical studies of Stegosaurus (aside from Marsh's remarks) are still available online in many places as well. These older papers include the 1914 comments of C. W. Gilmore on the osteology of armored dinosaurs in general. The book includes a number of line drawings of Stegosaurus and other armored dinosaurs. The drawings of Stegosaurus are worth looking through the pages of the book. The number of illustrations in the book of Stegosaurus alone is staggering and, as someone that always encourages reading the original descriptions, Gilmore's treatment of Stegosaurus is a read I certainly highly recommend.

07 March 2016

Stegosaurus Goes to London

Comprised of 300 bones, the most complete Stegosaurus discovered and the only Stegosaurus skeleton at the Natural History Museum of London was named Sophie and mounted for display in 2014. Sophie is known to specifically be from the species S. stenops also. She is the only Stegosaurus on display outside of the United States of America and is unique in many ways.  Sophie is an 85% complete skeleton discovered in 2003 at a site called Red Canyon Ranch in Wyoming. The cranium of Sophie is disarticulated, allowing paleontologists to look at the entire makeup of the skull from angles that have not been explored in a Stegosaurus before. The video below from the NHM London details the science and the display mounting process. This is also detailed in this news article from The Daily Mail.

Additionally, here is a video of a further interview with Dr. Charlotte Brassey on Sophie and her work that is or was being conducted on the stegosaur.

06 March 2016

Kids Stegosaurus

Stegosaurus is a hit with young paleo- enthusiasts. Children love Stegosaurus. The dinosaur has a weird body that is enormous and a tiny head. It also has amazing looking plates on its back and tail spikes that are very frightening because they are almost as large as some small children. As a charismatic dinosaur, Stegosaurus appears in a lot of children's books, toy lineups, movies, and generalized documentaries about dinosaurs. The genus is always used instead of a specific species, but bringing new eyes into looking at the genus level may eventually lead them to discuss the species differences and maybe even have a favorite species within Stegosaurus. The knowledge about the dinosaur has to start with simple facts like those from LiveScience and Enchanted Learning. In the case of Enchanted Learning, the art is typical of the site, but the skeletal and soft tissue anatomy presented entertain a better understanding by "lay people" (a phrase some scientists use for the public that I had heard tossed around lately and personally do not like) of the anatomy of dinosaurs. An educated dinosaur enthusiast is our goal here and as such I definitely encourage everyone to look over the site. It could use some improvement of course, but it is a good place to start which is the premise of all education. For those that like their dinosaur facts delivered by cartoons singing/rapping or talking to them, there are two videos.

The first video is new to me, from a website called

I'm a Dinosaur brings us a strangely team centered group of stegosaurs from Colorado. I like it.

05 March 2016

Day Later

My laptop is acting ludicrous, so I missed Saturday's post because I did not sit down at the computer until after 6, which is when the computer decided to stop working correctly. I have it limping along at the moment and can use it until the one I ordered this morning is shipped.

(C) Bob Nicholls
Today is dedicated to both Saturday and Sunday (these will be split on the external blogger page to be "published" on their respective days. Saturday sees wonderful paleoart that has not been posted from Bob Nicholls. Stegosaurus was one of the heavily armored dinosaurs that most likely used their spikes and plates for defensive/offensive reasons much more than for signalling or sexually dimorphic reasons. There are certainly potential signalling and dimorphism connotations for both the plates on a stegosaur and the tail spikes. However, there has been wound evidence attributed to the tail spikes and their use as a weapon is fairly likely given the evidence of musculature in the tail and hip and posture of the dinosaur overall. These appear to indicate an animal capable of generating a great deal of momentum and force with its tail end. The plates may have also had more physiological attributes and applications. Hypotheses of this nature have been considered many different times since the discovery of Stegosaurus and the debate about them is silently pulsing even now. It is a debate that really has not gone away over the years. The Brynn Metheney artwork featured a Stegosaurus with solar panels attached to its plates, which at least one side of the debate considers a perfectly logical use of the plates. In that scenario the plates could be used for heating or cooling the animal.

04 March 2016


Last week extenuating circumstances did not really allow me to write up the weekend entries prior to my scheduled busy weekend. Instead, I decided not to write at all the past week and to save February's dinosaur calendar dinosaur (Saur: Mission 2016) for this week, even though it is the first week of March. The trouble, the only problem really, with the calendar dinosaur for February is that it has been covered both before this page was its own entity and in a revision series where I was going back over the fun little side project entries before Dinosaur of the Week became its own standalone thing; this was back when I used my personal Facebook page for these daily writings and no one knew it existed. Regardless, Stegosaurus is a popular dinosaur that we have now discussed three times. There are still many links, papers, and books that we have not discussed, not to mention new popular culture references, including the calendar and other artwork that has been created since that time. Due to the fact that we have covered Stegosaurus so many times, I think it is only appropriate that we discuss the species level taxa more in depth than previously. However, we will still discuss Stegosaurus as a genus as well.

(C) Brynn Metheney
Stegosaurus, as we all know, was a North American dinosaur with ties to the "old country" in cousins and sister groups spread across the entirety of the landmasses that at one time made up Laurasia. Notably Stegosaurus as it is popularly known is the state fossil of Colorado, but the genus is split between three recognized species (S. ungulatus Marsh 1879; S. stenops Marsh 1887, type species; and S. sulcatus Marsh 1887) that are very little known. This is because Stegosaurus as a genus is the name that everyone in the public sphere generally uses to discuss a dinosaur with vertical plates on its back and spikes on its tail. The dinosaur that people know best is the type, S. stenops, and rightly so, as it is the species with the most articulated skeletons discovered in the genus; this includes one "complete" individual. Stegosaurus stenops was also the shortest of the three species, measuring 7 m (23 ft) from nose tip to tail. Stegosaurus  ungulatus is the most widely known globally with a specimen attributed to the species from Portugal and has smaller back plates than S. stenops. Stegosaurus sulcatus is differentiated by plates but also by its appreciably large tail spikes. These spikes are larger than in either other species. All of this talk to tail spikes and back plates may seem reminiscent of entries on ankylosaurs and there is a reason for that. Stegosaurs belong to a clade known as Thyreophorans, the same group that encompasses the heavily armed and armored ankylyosaurs. Their name, Thyreophora, comes from the Greek words meaning "Shield Bearers" and in both groups the armor that they carried on their backs is quite evident.