STL Science Center

STL Science Center

23 June 2017

Illustrated or Not

As usual this week, this entry is a little shorter than our typical entries for any given subject. As interesting as illustrations about Triassic subjects can be, especially considering the majority of these animals that are illustrated are early dinosaurs. Dinosaurs that do not look much like what people expect dinosaurs to be are intriguing and sometimes confusing to many people; this is a conversation I have had many times over with random people. One of the more interesting illustrations that does exist of Efraasia is slightly older and depicts Efraasia walking almost quadrupedally, but with its hindlimbs in a position that suggests bipedal locomotion. This illustration, like all the other illustrations of Efraasia simply depicts the animal as is by itself and without any kind of background. This version of the sauropodomorph is simple, but does have odd fingers, and is somewhat salamander like in its general appearance.

22 June 2017

Size of the Dinosaur

Efraasia was originally considered to be a small animal, based on fragmentary remains that could not be assembled extremely well, but it was later realized that the animal was much larger than believed. The estimated larger size is approximately 6.5m (21 ft). The dinosaur was still small for its size, but by small we mean gracile and lightly built rather than short or thin. The gracile hands and feet of the animal could be used to imply facultative quadrupedalism, though this is also implied by the fact that may other very early sauropodomorphs were known to be capable of moving bipedally and quadrupedally equally well. Poor pronation of the forearm, as some have hypothesized, may have limited Efraasia as an entirely bipedal dinosaur. Its gracile hands and digits were probably quite capable of grasping food items (and predatory animals and intraspecific competitors) which could then enable it to better survive its environment by adapting its diet (and defending itself more capably).

20 June 2017

Writing in Efraasia

We mentioned a number of articles, descriptions, and re-descriptions of Efraasia and thankfully there are a lot of examples of this writing hosted online in many different places. Only one of these writings is entirely about Efraasia and that is the Galton 1973 article that was previously described here. The paper (hosted on Springer's site), as many may remember, re-described a number of specimens collected by Eberhard Fraas and reassigned these specimens to a new genus named after a contraction of the collector's name; Eberhard Fraas was turned into the name Efraasia minor in this dinosaur.

19 June 2017

Efraasia in Motion?

Unfortunately Efraasia never made it, yet at least, into any documentaries, cartoons, or movies. There really are not too many movies that use Triassic animals though, so the fact that it has not been in any movies is a little less surprising than the idea that it has not been in any documentaries. Cartoon dinosaurs are typically the more famous of the dinosaurs, so its exclusion from cartoons is equally anti-climactic. The only other video online, actually, is from a young man reading about and discussing Efraasia from Stephen Brusatte's published dinosaur field guide. Barring any other videos, which I would gladly post, here is the single video that is out there:

18 June 2017

A Known Dinosaur

Efraasia is a well known dinosaur and has some of our typical webpages (e.g. Prehistoric Wildlife and Dinosaur Facts) to share facts about this sauropodomorph. These facts are read over a great set of images in the following WizScience video.

17 June 2017

Lesser Sauropodomorphs

Efraasia minor (von Huene, 1907–1908) was a gracile middle-sized sauropodomorph of the Late Triassic of Germany. The name was not actually coined by von Huene, despite the fact that he originally described the fossil remains. The name von Huene gave the remains was Teratosaurus minor; this genus is a group of rauisuchians, which Efraasia was deemed to not be a member of. The name we use was coined by Peter Galton in 1973 when he reassigned a number of specimens to the new genus named after the collector of the specimens, Eberhard Fraas. Estimated at approximately 6 to 7m (20 to 23ft), Efraasia is a respectable size for its time and place, but, as we can see, it appears to have been a rather generic looking early dinosaur; however, it is a generic dinosaur that stands out for a number of reasons that we will discuss this week.

16 June 2017

Plain Illustration

Most of the illustrations of Tarchia are fairly plain. These are mostly lateral views of the dinosaur in a static posture that shows a lot of what the dinosaur could have looked like from the side. There are not very many dynamic poses that are out there of the dinosaur that show it by itself, but this is also okay. One of the best piece of art I have actually found relating to Tarchia is a statue. The statue is a scale model of both Tarchia and Tarbosaurus engaged in one of those epic dinosaur battles that has long captivated the public audiences. The art is a collaboration between Vladimir Trush and Vitaly Klatt. Trush appears to have sculpted a number of Tarchia inspired statues.

14 June 2017

Thursday Already

The material of Tarchia is terribly incomplete to the point that size estimates of the animal are based on completely different animals, have been estimated from the smallest known remains at times, and have been independently made but not verified across a number of sources. This has made the dinosaur difficult to model in a popular context without arbitrarily picking one or another size estimate as the size of the model that will be illustrated, animated, or sculpted. It is partially this reason that there was no animated Tarchia until Dinosaurs Alive! was produced and other ankylosaurs of Mongolia were used in previous videos and films depicting that area of the world and its dinosaurs. Looking at these various estimates of size, however, Tarchia may appear to either have been the longest of Mongolian ankylosaurs with an estimated length of 8m (26ft) or a modest 4.5m (14.8ft). The upper estimate of 8m places Tarchia in the same size category as Ankylosaurus whereas the 4.5m estimate is within the range of Nodosaurus sized ankylosaurs. Basically this means that Tarchia was either a typically sized, though longer than any other Mongolian, ankylosaur or it was a smaller member of the ankylosaur family. This is important to our discussions on popular culture because the Tarchia model used in Dinosaurs Alive! appears to be of a similar size to the Tarbosaurus it is shown fighting. Tarbosaurus measures in with a range from 10m to 12m (33ft to 39ft) and even at its largest estimates this would be oversized for Tarchia.
Larger Size Estimate

Smaller Size Estimate (image by Conty)

13 June 2017

Discussing the Skulls of Ankylosaurs

There are a number of articles and citations for Tarchia. There are a lot more citations than full articles online, but there are still articles that discuss the dinosaur, so those that learn by reading are not at any kind of disadvantage this week (i.e. there is plenty of material to read and learn from about Tarchia). The most important and useful articles that exist online as full articles are possibly the most important articles in the current body of literature for Tarchia outside the initial description by Maryanska. The first is the description of the junior synonym Minotaurasaurus ramachandrani which describes what the authors (Miles and Miles) interpreted as a unique and novel cranial structure unknown before the discovery of these remains. The second article linked here today is the Arbour, Currie, and Badamgarav, 2014 that re-describes both Tarchia and Minotaurasaurus (as well as many other ankylosaurs of Mongolia) crania interpreting similarities, differences, and variations within the genus. It is worth noting that these authors mentioned that Minotaurasaurus is a fossil lacking provenance and was purchased at a mineral and gem show but has been hypothesized to have been recovered from Mongolia by Dalton 2009. The authors consolidated Minotaurasaurus as the same species as T. kielanae, but they did interpret the remains of another animal, Dyoplosaurus giganteus, as similar enough to belong to the same genus and redesignated the animal as T. gigantea; I have not looked up how this species was erased from the taxonomy so cannot offer more as to why it is no longer included in the Tarchia family tree.

12 June 2017

The Quiet Documentary Star

Despite the seemingly forgotten nature of Tarchia after the first decade or so of its known existence, that is to say after it was initially described, Tarchia managed to remain known enough that it was featured in a documentary in 2007. The IMAX movie Dinosaurs Alive! looked at the Triassic fauna of New Mexico and the Cretaceous fauna of Mongolia. The Mongolian desert scenes lean heavily on Tarbosaurus, but in its treks the large tyrannosaurid runs into a Tarchia. No hilarity ensues, but a short altercation does and it ends with Tarchia knocking Tarbosaurus off its feet and sending it into the sand.

11 June 2017

Tarchia Facts

Here is a video full of facts about Tarchia today. There are also a number of websites that contain facts about this strangely little known ankylosaur; I say strangely because during the first decade after its description Tarchia was actually fairly popular. These include ThoughtCo, the Natural History Museum of London, and Prehistoric Wildlife.

10 June 2017

Back to Tanks

©Nobu Tamura; listed as Minataurasaurus
The name Minataurasaurus is a fairly awesome name, in my opinion. Unfortunately it has been recently decided that Minataurasaurus is a junior synonym to an ankylosaur described by Osmolska in 1977 known as Tarchia. There are two species in this genus; Tarchia kielanae Maryanska, 1977 and Tarchia teresae Penkalski & Tumanova, 2016. Overall Tarchia is a fairly typical ankylosaur but the holotype name references a somewhat unique feature of the animal: a larger brain than other ankylosaurs. This may be in the eye of the beholder (Maryanska) or it may be supported by the remains of the animal; hopefully this will be something we can address later this week. The generic name comes from the Mongolian word for brain, tarkhi, and the scientific name refers to a part of the name of the leader of the 1970 Polish-Mongolian expedition that discovered the fossil, Zofia Kielan-Jaworowska.

08 June 2017

What Makes A Dinosaur Popular?

Since the discovery of Citipati it has been a bit of media darling and a very popular dinosaur with the general public. The dinosaur has appeared in books and cartoons, documentaries, movies, and shorts, and has been a very popular subject for illustrations, toys, and statues. The dinosaur's name comes from a Buddhist deity, meaning that searches for either bring up the other, only increasing the search popularity of both. We could look at any number of these outlets and even talk about the Buddhist inspiration of the dinosaur's name, but instead, we can see here how others are envisioning the dinosaur as a video game character. It does have a rather dodo-esque bill here, but it is an interesting interpretation.

07 June 2017

Continuing From Last Week

©Edyta Felcyn (Apsaravis)
Continuing where I left off last week, we can see that Citipati continues to be an animal that is often illustrated and has been studied not only for its interesting anatomy but also its peculiar behaviors. As with many of its kin the oviraptors, Citipati was an apt nest-tender and has been discovered many on separate and independent times on, in, or around its nests. Its eggs have, likewise, been recovered on numerous occasions and have even revealed whole embryos as well as hatchlings. These embryos and newly hatched oviraptors began life little taller than the average human knee (assume your own knee is within an acceptable range and attribute height differences to variation; how unscientific of me!). The adults would have been approximately 3m long and, in natural pose, approximately 1.8m tall. Assuming that the growth of these young Citipati was somewhat quick, perhaps even rapid, the combination of quick growth and the known brooding habits of Citipati says an awful lot, as we saw in papers last week, about inferences made into the history of avian style brooding as it relates to and is evolved from this maniraptoran style of brooding. The nesting position is often depicted in a singular manner, and for those not aware, this looks very much like this first image. The second image is a slight alternative, but the difference in the two images is most likely a question of heating or ventilating the nest to maintain proper brooding temperature.
©Edyta Felcyn (Apsaravis)

30 May 2017

Citipati's Anatomy

The skull of Citipati is among the most iconic skulls of all theropods, if not all dinosaurs. This skull has brought about much interest and description. The original description of the material, of course, is online and is worth reading. The paper includes detailed photographs of the skull Citipati and a second description of another oviraptorid, Khaan mckennai. One of the original descriptions was published less than a year after the description of the original material as a re-description of the cranium by Clark, Norell, and Rowe with comments on another specimen, Oviraptor philoceratops. This paper contains a detailed description of the cranial material and multiple angle, well labeled, photographs of the holotype cranial material, skull and mandible, that are very helpful for understanding the overall anatomy of the skull. The publication also includes CT scans of the material. Beyond the anatomy, Citipati has been used as a basis for parental care in dinosaurs and to explain the origins of avian parental care. Their nesting and parental care has also served as the base for growth studies in nesting dinosaurs. The reason that there are so many studies of Citipati eggs, nesting, and growth is because there have been many finds of Citipati on their nests as well as eggs containing Citipati embryo without the parents found nearby.
Photo by Jordi Payà from Barcelona, Catalonia

29 May 2017

Forget Everything but the Short

There are a few mentions of Citipati in different documentaries and news stories, but rather than posting any of those today I think that the only video we need to really watch is a beautiful short showing Citipati. Unfortunately the entire short does not appear online. However, the trailer to the short (and the fact that it won an award) make me really want to find the entire film to share with everyone here. The film shows Citipati in an everyday-life situation that then gets turned upside down and shows Citipati in an environment that really evokes the namesake of the dinosaur; the Buddhist protector deity and "Lord of the Crematorium" Citipati. Please find the trailer, posted by the creator Andreas Feix, below, and take a moment to enjoy the film that you can see. I hope to hear from Andreas to be able to share the full short with everyone soon.
Citipati (2015) - Trailer from Andreas Feix on Vimeo.

28 May 2017

Podcast Win

Despite the well-known nature of Citipati it is probably important to note that the dinosaur is still relatively new in terms of dinosaurs and their presence on the internet. There are news stories floating around and a number of other assorted websites that specifically mention Citipati. These include sites like Prehistoric Wildlife, the Natural History Museum in London, and the I Know Dino website. However, to get right at the crux of the Sunday theme, we can turn to the I Know Dino Podcast, rather than just using their website as a source, to summarize the majority of websites.

27 May 2017

Another Missed Dinosaur

I truly love finding that I have somehow overlooked a dinosaur that I am and have been aware of for quite some time. This week that dinosaur that I suddenly remembered existed is Citipati osmolskae. Citipati is one of the better known oviraptorids and one of the most iconic members of its family. Possessing a crest on its forehead and a beak characteristic of other oviraptorids. Probably covered completely in feathers, Citipati was a large dinosaur at approximately 3m (10ft) long and were the largest members of their family known between 2001 and 2007. Clark, Norell, and Barsbold named Citipati (Hindi for funeral pyre) after the highly successful paleontologist Halszka Osmólska of Poland. Osmólska was a prolific discoverer and describer of oviraptorids and theropods of Mongolia where Citipati was also discovered.
Display from "Dinosaurs. Treasures of Gobi Desert" in CosmoCaixa, Barcelona.
Photo by Eduard Solà

26 May 2017

Polacanthus Presents Itself

©Rodrigo Vega
There are a number of different interpretations of Polacanthus in a number of different views. There are also a number of different actions being undertaken by these interpretations of Polacanthus ranging from sleeping to evading and actively engaging predatory dinosaurs or intraspecific rivals. The type of action in which the Polacanthus in any given interpretation does not necessarily relate how intriguing or impressive the individual piece is; a sleeping Polacanthus has exactly as much potential as a running animal. I would actually go so far as to say that the sleeping Polacanthus image shared here today is almost more dynamic than the second image.Rodrigo Vega's sleeping Polacanthus is the centerpiece of a rather dark image. Two small Hypsilophodon occupy the cliff protecting the large sleeping ankylosaur from above. The Polacanthus itself is quiet and almost appears to be somewhat contemplative. Though I have described it as asleep, it almost appears awake but with its eyes closed which is a very real possibility of course. This, like many ankylosaur illustrations, is a solitary animal living a lonely life. The Hypsiolophodons above the animal may have acted as a portion of a surrogate herd, as animals like Polacanthus are hypothesized to have lived solitary lives except at points where they needed to be around their own kind (i.e. during mating seasons). There is the possibility that this kind of behavior would be related to poor eyesight  on the part of the ankylosaur; essentially it would have used its non-conspecific herd members as its eyes to be aware of predatory dinosaurs.

©Will Brennan
This could be the exact circumstance of the second illustration of a much more awake Polacanthus. This Will Brennan image might be portraying a similar herding behavior in which Polacanthus has adopted a group of Iguanadon as surrogate herd members in the place of other Polacanthus (and smaller animals like Hypsilophodon). The Polacanthus in this image is actually a part of the foreground and is a secondary character of the image. The illustration itself draws the eye to the center with the light in the distant forest and the central Iguanodon braying or calling the herd together. Assuming that the herd is being called together and Polacanthus is a member of the herd that understands this call, that would mean that are smaller ankylosaur was willing to separate itself from the herd in deeper woods, allowing the safety of numbers to be minimized in this situation.

All of these interpretations are, of course, my personal speculation based on the speculation of artist interpretation of events that may or may not have occurred and may or may not have some kind of scientific evidence underlying them. The most important thing to do with these illustrations is to enjoy them, appreciate them, and create your own ideas about what is happening in them.

24 May 2017

Pelvic Polacanthus

Tuesday there was a paper describing the pelvic armors of different ankylosaurs and Polacanthus was one of the ankylosaurs that was specifically mentioned because it possessed very unique pelvic dermal armors. Most ankylosaurs have somewhat uniform sheets, scutes, or patches of dermal bone that protect their dorsal surfaces. Polacanthus also has dermal armor along its back; however, the dermal armor along the pelvic region is uniquely constructed and protective of the dinosaur's pelvis and hips. Assuming that, as many ankylosaurs are thought to have defended themselves, Polacanthus made itself small when threats loomed, making it difficult to get at its soft underbelly, the expansive pelvic armor was capable of protecting the hips of the animal quite well as it would have served as an armored roof to that area. In many illustrations it appears as though the hips are still exposed (such as that below); however, in the skeletal reconstructions of Polacanthus we can see fairly well that the actual hip socket lies medial and ventral to the armored shelf of bone resting on the pelvis. In some line illustrations this has been exaggerated slightly, such as in the Nopsca drawing which pulls the shelf more laterally than some others, but these small errors in representation do not change the fact that the armored shelf protected the hips of Polacanthus very well and probably kept the dinosaur safe from most direct bites, slashes, and kicks to the hindlimb which, as we saw with Edmontonia, was most likely used to pivot the front shoulder spikes of Polacanthus in threatening displays or actual offensive strikes at rivals and predators.
©SADistikKnight (Robert)

23 May 2017

Polacanthus the Printed

Not surprisingly, there are a lot of papers on the armor of Polacanthus and its configuration. Of course, we should start with the original descriptions of Polacanthus fossils but there is only one of those available online. The first few description papers are short and largely unimportant; however, Hulke's 1881 description, featuring a number of quality line drawings of the known fossils to that time, is online and is worth reading. This was followed up approximately 20 years later by a review of English dinosaurs by Franz Nopsca with a dedicated chapter and new descriptions of Polacanthus. This trend of description has continued off and on through a number of different publications, researchers, and specific foci of research in general. The latest descriptive paper of Polacanthus actually describes a number of ankylosaurs and, specifically, focuses on the pelvic armor and its variations across all ankylosaurs.

22 May 2017

Park Darling

Polacanthus has appeared in a number of documentaries (including two episodes of Walking with Dinosaurs) as a major figure. However, the bulk of non-amateur created videos of Polacanthus are documented interactions of visitors to animatronic dinosaur parks with the statues at the parks. Not all of these moving statues are accurately built, meaning there are a lot of versions of this dinosaur at parks and "fossil zoos" that do not accurately portray the animal. The best model is the one shown below, though this clearly has some interesting individuality sculpted into it.

21 May 2017

Learn Your Polacanthus

Polacanthus is a bit more popular than a large number of other ankylosaurs and, by being one of those more famous and known dinosaurs, has a lot more pages and videos dedicated to it online than others. These include sites like KidsDinos and Age of Dinosaurs. As we know, most websites contain similarities and work with the same set of information to build their fact files and paragraphs of information. The same can be said for most videos. The prime example of this is the WizScience video series that relates the same information over a series of images of the fossil animal in question. Strangely, there is no cartoon for Polacanthus like the I'm A Dinosaur series; given its popularity this is a little strange.

20 May 2017

More Ankylosaurs

During the past week I made mention of different types of ankylosaurs including their namesake group, nodosaurs, and polacanthids. This week to continue painting that picture and better understand what makes each kind of ankylosaur fit into that familial relationship, we will discuss the polacanthid Polacanthus foxii, the namesake of its subfamily. Polacanthus was originally discovered by the Reverend William Fox of the Isle of Wight in 1865; hence the specific epithet. This came about because the reverend, disliking a name given by Lord Alfred Tennyson (Euacanthus Vectianus), the first describer of the fossil, presented the fossil to Richard Owen with the new name in tow; this information is attributed to an anonymous pair of 1865 sources thought to be by Owen, Fox's own 1866 writings naming Owen, Huxley's 1867, and Hulke 1881. Regardless, Polacanthus was an ankylosaur of respectable size, measuring in at approximately 5 m (16 ft) and weight estimates of approximately 2 tonnes. Featuring armor and spikes similar to other ankylosaurs, Polacanthus was not a typical armored dinosaur and possessed unique armors, especially over the pelvis, that separated it from its closest relatives in unique ways.
Model in Sandown, Isle of Wight, Photo ©Henry Burrows

Special Edition - Save the Fossils and Their Land!

peak out for fossils! Executive order 13792 mandates a review of the boundaries of 21 US national monuments, including two whose express purpose includes protecting vertebrate fossils -- Bears Ears and Grand-Staircase Escalante. Both monuments are in southern Utah and both contain rich vertebrate fossil resources.

Please consider commenting that the boundaries of Grand Staircase-Escalante Monument should be maintained and and those of Bears Ears expanded.

Comment submission form:

Deadline for comments on Bears Ears and Grand Staircase-Escalante is May 26.

18 May 2017

Famous Dinosaurs

The popularity of Edmontonia is rooted mostly in its representation in the fossil record. Some very popular and well known dinosaurs have not been well represented in the fossil record, so we can certainly say that it is possible to be poorly represented but very well known. Edmontonia is one of those dinosaurs that is both well known and well represented. Due to this popularity it appears in video games, card games, documentaries (announced simply as "an ankylosaur" in the linked video), cartoons, books (too many to list), and almost any other medium one can think about. I like to share, when they are available, these images from information cards on dinosaurs because they re the kind of things that I used to love when I was a kid and really got me into dinosaurs (of course I am a huge nerd though). These summarize some of the things we know about Edmontonia at the same time as making the animal appear dynamic and interesting to people that would consider themselves dinosaur enthusiasts. They serve the purpose of a popular culture outlet in that way exceedingly well, and are therefore an important resource for popularity day here.

17 May 2017

Dermal Armor and Spikes

E. rugosidens, specimen AMNH 5665
Photo ©Shriram Rajagopalan from Vancouver, Canada
The armor of nodosaurs is generally similar across taxa with variation changing sizes, shapes, and numbers of plates and spikes depending on not only the genus or species, but also the individual animal. Edmontonia, for the most part as a genus, possesses armor that is constituted of flat, mostly smoothed, dermal plates starting with laid out rounded rectangles in organized rows from the neck into the tail. The skull and head lack dermal plating entirely. Over the pelvic and pectoral girdle the dermal plating is significantly different, making the armor patterns similar over the torso and abdomen and pelvis and tail. The torso and abdomen pattern consists of large oval plates guarding large areas of the rostral back (dorsum) of the animal whereas from the pelvis to the caudal-most plates the shape of the plates is more spherical and the shapes are more populated. This causes the armor to leave smaller gaps, possibly providing greater overall protection from crushing bites and injuries than the more rostral armor. The trade-off is in the sizes of spikes and mobility; not to mention Carpenter's hypotheses of sexual dimorphism and/or age as judged from the sizes of shoulder spikes. Nodosaurs do not have tail clubs like ankylosauridae genera nor do they have vertical spikes or sheets of armor across their pelves like some polacanthinidae genera. Instead, nodosaurs like Edmontonia possess large lateral spikes across their shoulders with smaller spikes trailing down to the pelvis, a trait that has led to many representations of nodosaurs hopping about to thrust their shoulder spikes at attacking predatory dinosaurs. The smaller links of armor around the pelvis would enable such movements as the plates would not take up as much space and could be compressed well as the animal twisted and turned. Additionally, the large plates could be similarly manipulated to manipulate the shoulders, but larger plates need more space between one another to move in a similar fashion, which could account, in part, for the large gaps between plates in the torso area. These large gaps could have also enabled the animal to look upward at a slight degree as the spacing between rows could be compressed as the head and neck pushed the extreme rostral rows of dermal plates back toward the shoulders.

Please remember that these are hypotheses based on looking at fossils, the papers of others, and generally restating shown interpretations of the animal already distributed via film and screen and that we still have many unanswered questions about these very interesting animals. When traits like spikes and armor plating are highlighted everyone automatically (it seems) thinks of two possibilities: defense or mating. The defensive capabilities of nodosaurs like Edmontonia are fairly clear in looking at the skeleton and associate spikes and dermal plates: a large, but squat, animal with hardened scales on its back and large sharp protrusions of bone was probably very good at getting low and defending itself regardless of how it actually managed it. If its shoulder spikes were used as offensive weapons they were probably used mainly to intimidate as they would otherwise need to be picked up, moved with speed, and very accurately aimed. Any movement that elevated and sped up the body of this animal would have left the unprotected underbelly exposed long enough that it could have been tragic. This leaves us with two possibilities, as I see it: Edmontonia was much more turtle-like in its defense of itself or it was a brash and intimidating animal that attempted to scare away predatory dinosaurs rather than actually fight them. Both of these possibilities are intriguing and the behaviors behind both could be fascinating. Please feel free to discuss the likelihood of either or both scenarios. I enjoy these kinds of conversations and thoughts.

16 May 2017

Edmontonia the Northern Dinosaur

Whenever we hear and see discoveries from the extreme northern or southern areas of the globe there is a certain amount of amazement not only because of the remoteness of the discoveries, but also because of the idea that dinosaurs lived in colder areas. This, of course, is regardless of the current climate in these areas. There are hypotheses of the climate, seasonal change, and temperatures of places like Antarctica and Alaska. These are discussed in the literature concerning Edmontonia on a fairly regular basis because many examples of the animal have been discovered at higher latitudes in both Canada and Alaska. New species of Edmontonia were hypothesized from Alaska during the 1990's, such as in this Gangloff article from 1993 calling the remains the first ankylosaur remains of their kind from Alaska. A great deal of the Edmontonia articles do not reach as far north but stop with remains from Dinosaur Provincial Park in Alberta, which has held a wealth of Edmontonia remains that have been recovered. This has led to many studies revealing more about cranial anatomy, flexibility in naturally occurring dermal armors, or even the teeth of Edmontonia (or whatever ankylosaur you are personally interested in).

15 May 2017

Watching A Drawing

Sometimes my favorite videos are not portions of documentaries or news stories. Some of my absolute favorites are actually sped up art videos. Whereas I have a few not-so-good documentary clips and one fairly nice time-lapse artwork image, I choose to share the artwork today instead of the weak documentaries. There are nodosaurs in documentaries that are based off of Edmontonia more than any other nodosaurs; however, given that these are only based on the dinosaur and do not expressly discuss the animal, the artwork video is still a slightly better choice for sharing today. Enjoy!

14 May 2017

Nodosaur Facts

For Sunday's fact entry, I am choosing to link a few videos. The I Know Dino podcast about Edmontonia says anything and everything I could in a nice quick format. I Know Dino is run by a team of dinosaur enthusiasts that has made digging up and presenting information about dinosaurs their number one goal.

The Dinosaur Diversity lecture in University of Alberta's Coursera lecture series also discusses, and shows, Edmontonia and the anatomy of the dinosaur. This lecture can be found here.

13 May 2017

Edmonton's Nodosaur

In the news lately there has been a lot of talk about a nodosaur mummy. This week, therefore, I thought it would be prudent to discuss a nodosaur, though honestly a totally different nodosaur than the fossil mummy. This week's nodosaur is known as Edmontonia and the genus contains two species: E. longiceps and E. rugosidens. Nodosaurs like Edmontonia were covered in osteoderms and armor that we will see plenty of this week. Known from materials originally discovered in 1915 from the Edmonton formation of Southwestern Alberta. Specimens have been discovered as recently as 2010 and the taxonomic history of the genus is interesting and complicated. A lot is known about Edmontonia and so we will have a lot to discuss this week, but before we do, appreciate some art based on the original finds.
©E.M. Fulda, 1922; based on the 1915 AMNH specimen

12 May 2017

A Busy Day

Yesterday was busy, so here is Friday's artwork on Saturday afternoon (I will get you all a new dinosaur/fossil within the next few hours). The artwork I shared the other day was a brilliant family portrait of a Troodon and three young animals on a beach. I could easily put another well done family illustration as there are plenty of them online; Troodon families are apparently a very popular motif in the paleoart world such as Blair Sampson's woodland family illustration. This extends not only to young animals but also to eggs and groups of adults as well. Groups of Troodon are, simply stated, popular topics for people to draw and paint. As long time readers know, I prefer well thought out or imagined artworks that challenge our preconceptions or show active and energetic animals. Unfortunately, there are a lot of Troodon images online that are one or the other but not very often both active and imaginative. This image comes from BBC's Prehistoric Planet, which shows the dinosaur in many active and imaginative situations. The feathering that was placed on this Troodon is rather extensive, but looks very well thought out, not simply plugged in to make a completely feathered dinosaur.
©BBC, Prehistoric Planet

11 May 2017

Seen on Video

Dale Russell and Ron Seguin, 1982 
Canadian Museum of Nature, Ottawa, Canada
Troodon has appeared in so many popular venues from books to video games to movies to toys that it is nearly impossible to focus on any single area of the dinosaur's sphere of influence. Instead, we should look a little closer at Dale Russell's interpretation of Troodon evolution and the hypothesis of its continued and increasing intelligence. This hypothesized animal was dubbed Troodon sapiens by Russell and was given form by sculptor Ron Seguin in 1982. I remember seeing it when I was young and being impressed and a little confused. The idea that other forms of animals could take on humanoid forms in the course of their evolution was very odd but not out of the realm of possibility. An intelligent dinosaur, like Troodon, that had been able to evolve (without a major extinction event limiting them), would have potentially been capable of evolving large heads and changing their posture. Therefore, Russell's hypothetical "Dinosauroid Man" was not, and is not, actually all that bizarre. Though any dinosaurs, intelligent or otherwise, could have potentially evolved into more upright, tail-less, postures over millions of years. The fact that someone put that idea into a solid form and wrote a paper about that idea is bold, but that did not endear Russell to everyone. Though I do not know how controversial the "thought experiment" was or still is, it was apparently controversial enough that many disliked it. One of the chief complaints, and what makes it so eerie, is the extent of the antrhopomorphic characteristics of this evolutionary experiment. As I mentioned on Monday (or Tuesday because I mixed up my days), discuss this sculpture, but do not lose friends over it!

10 May 2017

Anatomy of A Stereotypical Dinosaur

Troodon is nothing if plain looking in terms of dinosaur morphology. In modern terms that even includes the inclusion of feathers along both limbs and the majority of its body. The more numerous, and older, portrayals of Troodon are still out and flooding the internet with gracile dinosaurs that look emaciated and a strange oily green-black skin. That skin was typically portrayed as smooth rather than scaly but it is not overly important, considering that the interpretation and knowledge of what Troodon probably looked like has changed and become so much more feathered. Troodon was not, as we tend to see stereotypical gracile dinosaurs thought of, a small animal either. The dinosaur was approximately 2.4 m (7.9 ft) long and tall enough to rival the average human, though at 50 kg (110 lbs) it was the weight of a large dog, which many of us know does not need to be tall to knock down an average sized human being. Exhibiting eyes that face partially forward, indicating depth perception capabilities, that were rather large proportionally, indicating a potentially nocturnal lifestyle, and a brain that was equally proportionally large for its size, Troodon was most likely a very intelligent animal. Intelligence has been debated for a long time in fossils, but Troodon, for many years now, has been generally accepted as an intelligent dinosaur that was capable of manipulating its manual claws, i.e. that it was able to grasp and manipulate objects. This has many implications, including the idea that intelligence and social behavior often go hand-in-hand. That idea specifically has led to many great interpretations of the dinosaur and its capabilities and has told us a great deal about the intelligence of these animals once thought of as slow, stupid, and mostly solitary outside of herds.
©Taena Doman

09 May 2017

Monday on Tuesday

I happened to think yesterday was Tuesday apparently for some reason. The post related to Tuesday and literature therefore appeared yesterday which means that today we will look at some videos concerning, describing, and generally about Troodon. These videos are informational, educational, and entertaining, sometimes all at the same time and sometimes one way at a time or a combination of these. When searching Troodon online it is important to skip a few pages of results, as the only items on the first few pages relate to the ARK video game and videos that are made using its models. The first documentary that appears is an old Discovery documentary discussing, specifically, the intelligence of Troodon including Dale Russel's hypothesized Troodon evolution; for those not acquainted this is a very humanoid version of a highly evolved dinosaur which is shown and discussed at length in the documentary. Troodon also appears in many other documentaries, but for tonite, the single documentary will suffice. It leaves a lot to be discussed between friends and colleagues and can lead to many happy discussions (or terrible angry ones if you choose that path).

08 May 2017

Smart Dinosaurs and Their Eggs

In the case of Troodon there are a lot of research studies and fossil discoveries centered around both the animal's intelligence and its nests. These studies of eggs are not relegated to the egg itself, but have even discussed embryos and nesting ichnofossils. The adult, and juveniles, have also been studied extensively. This includes their teeth, the microstructure of their bones, and their famous intelligence. This, of course, has led to many studies of the braincase and the endocast of the skull. The brain has not received any single treatise that demands attention and is also hosted online anywhere I can find it.

07 May 2017

Facts in Video Form

Today we have a short video about Troodon that goes over some facts about the dinosaur as told by the one of the dinosaurs. There are many other videos as well, but I think this video wraps up a good majority of the facts and presents it in a rather fun way.

06 May 2017

More Surprise Dinosaurs

©Greg Heartsfield, Perot Museum
Creative Commons Attribution 2.0 Generic
There are relatively few times these days when we encounter a dinosaur that we probably should have discussed previously but somehow we missed in the past. This week I noticed that we have somehow skipped a rather prominent dinosaur: Troodon formosus. Dated from 77 MA and originally recovered from the Judith River Formation of Montana. The first fossil was a tooth found in 1856 and described by Joseph Leidy (under the spelling Troödon), making Troodon one of the first North American dinosaurs found and described by Leidy, let alone anyone on the continent. These teeth were described as the teeth of a lizard initially. It was not until 1877 that the dental remains were redescribed and assigned to a place in the dinosaur family tree. The first skeletal remains recognizable as a dinosaur were discovered in the 1930's by Charles M. Sternberg in Alberta, Canada. Since that time many other skeletons and clutches of eggs attributed to Troodon have been discovered, recovered, and have been prepared. These remains have been discovered from a geographic range that includes Alaska, Wyoming, and potentially Texas or New Mexico; these finds are not conclusive at this time however.

05 May 2017

Not A Glamour Shot

This week has flashed by somewhat quickly. Typically, if available, I show a size comparison of the fossil animal to modern humans at some point during the week and I noticed that I have not done so this week. Anyone that has seen a Glyptodon fossil in a museum can very much appreciate the size of this fossil relative of armadillos without seeing such a size comparison. However, those that have not can view the first image shown here and begin to really gauge what this animal may have looked like up close. Despite being an herbivore, and most likely a relatively calm one at that, the sheer size of the animal and its carapace are daunting and, this is my speculation, would be terrifying to view with only a few feet or yards between the animal and an average sized human.

Moving away from the size comparison to look at a unique view of Glyptodon in comparison, we find this armadillo-like version of the ancestor to armadillos. Daniel Eskridge purposely and knowingly stresses that his art is art before it is paleo-art. Sharing this distinction straight away means that we can simply enjoy his interpretation of Glyptodon without complaining about how he got aspects of the animal "wrong" according to modern convention (not saying I think he did, just that some forums tend to focus on these things). These topics can still be broached, but appreciating the familiar looking snout of an armadillo morphed into an ancestral state on the body of Glyptodon makes this animal look less like a prehistoric creature and more like an animal that we could see in the modern wild. This sort of interpretation and believable subject is not uncommon in paleo-art, nor is it entirely frowned upon, but more and more the push for separating interpretation and scientific based representation, I think, is causing people to ignore some of the best endeavors of artists of the past in trying to recreate or interpret interesting soft tissue anatomy. Aside from this, the alert look of the Glyptodon and its head posture make it look curious but frightened at the same time. This gives the animal a somewhat innocent look as well. At the same time I think it underlies a very firm grasp on wildlife behaviors and how an animal that was interrupted at the stream might look at whatever (us in this case) interrupted his drink. As everyone knows, I appreciate paleo-art that is a little different and shares an intriguing new view of the animals we discuss here. This piece certainly does that.
©Daniel Eskridge; @deskridge;

03 May 2017

Anatomy of the Glyptodon

Fossil specimen at the Naturhistorisches Museum, Vienna
The anatomy of Glyptodon has been described over and over again and, because of this and the large number of known specimens, we can break down and describe this anatomy very easily. The vertebral column, eyesight, and skull and associated musculature are of great interest and we could spend a great deal of time on any or all of those individual areas. However, this post is going to specifically treat the most easily recognizable features of Glyptodon: the carapace and tail. The carapace and tail are both covered in osteoderms. Tracing the development of the osteoderms actually coincides with the evolutionary lineage of the species in the genus Glyptodon with specific patterns and sizes of osteoderms appearing across not only the tail and carapace but along the face, legs, and abdomen during the Pleistocene. Osteoderms began appearing in Glyptodon shortly after the North and South American continents were bridged. The current thought is that the osteoderms began becoming more regular and denser as a defensive response to more predatory mammals entering South America from North America. Prior to osteoderm enlargements, the Glyptodon carapace and tail were entirely smooth in appearance. This makes interpretations of Glyptodon somewhat confusing as Late Pleistocene Glyptodon, such as in the first image, are smoother in appearance and very Early Holocene Glyptodon appear to be rough, as in the second image.
Hungarian Natural History Museum

02 May 2017

Glyptodon on Paper

As one of the longer known fossil animals, a lot of articles, lectures, and descriptions of Glyptodon have been published. These have been published in peer reviewed journals and in annals of older collections of lectures and presentations. The older articles include descriptions of osteology by Huxley in 1865 as well as the dentition and partial skeletons of Glyptodon as reported by Owen in 1841. Glyptodon has never been solely an English find; as we saw yesterday the animal is known from South America also. Some works like Nodot's 1856 book (French) or Chavez-Aponte's 2008 article (Spanish) have made Glyptodon an internationally known fossil animal in multiple languages. As the years have gone by the articles have become more and more scientific, which is both a blessing and a little sad. Observation papers like Burmeister's 1864 paper on museum specimen observations have left us, but it was replaced by papers like Osborn's 1903 paper and more recent, more in depth and rigorous investigations. These include fetal remains, protein structures, and even estimations of body size based on limb proportions.

01 May 2017

The Movie Star Glyptodon

A number of Glyptodon videos are produced and published by amateur fossil enthusiasts. While these are good quality videos and worth mentioning, we have far too many videos of this peculiar mammal to share them all let alone discuss, fully, the few that we will share here. A few of the really interesting ones that are worth an extra look and the description that we will post here today include a news story about a fossil find, and an animatronic version of the big mammal. The news story comes to us from Ezeiza (Ezeiza Partido, Argentina) where a farmer, walking about in his fields, noticed an excavated area and the large fossil of the carapace-like structure of the Glyptodon sitting in the hole. Some have speculated that the shell of the animal may have been a hoax, mostly based on the hole in the shell, but Adrian Lister of the Natural History Museum of London was quoted as saying that the hole likely resulted from "wear and tear" and did not necessarily indicate"where the head or tail went".

The video of the animatronic Glyptodon was posted by the Sichuan Lituo Landscape Science & Technology Co., Ltd which manufactured the robotic mammals. These versions of the animals are possibly the most realistic animatronic versions that have been manufactured and put on display. There are others with odd mustaches and toupees and there is even one that walks very slowly and without bending its knees.

30 April 2017

Glyptodon Facts

The facts about Glyptodon are posted in many different places online and in a variety of videos. As I stated yesterday, many people recognize Glyptodon right away even if they do not or cannot recall the name of this large armored mammal. Because none of the videos that are posted about the animal show unique facts or interpretations of those facts that are not presented on the fact websites I will save the use of any websites until later. That, however, leaves us with copious amounts of literature to read about this interesting and odd shaped animal. The sites ThoughtCo and Prehistoric Wildlife present facts and detail some of what we know about the animal including its relationship to near contemporary animals and its descendants. These insights are, of course, useful in determining life histories, ecologies, and general life facts about Glyptodon. The Enchanted Learning site presents similar, but less, information about Glyptodon. It does, however, offer us a coloring sheet, something I have not posted in many months for our Sunday posts. Enjoy reading and coloring today!

29 April 2017

A Mammalian Tank

Good evening sports fans (I have been watching hockey today) and dinosaur fans. We are going to get back to dinosaurs soon, but this week we are going to look at a well armored mammal that I saw, remembered, and noticed I have never discussed on here at the Field Museum on Monday. A genus of the curious Xenarthran animals of South America, Glyptodons are armored animals with large curved teeth and an armadillo-like shell around its body. This should not be a surprise when I say that armadillos are close living relatives of the now extinct Glyptodons. Regardless of name recognition, the visual of a Glyptodon is typically quickly and readily identifiable; this may be the first time for some being able to place a name with the animal. Glyptodon tails are different across the genus, but we will see that their thoracoabdominal armor is fairly conservative across time and evolution.

19 April 2017

A Load of Anatomy

Petrolacosaurus kansensis was discovered in a smoothed layer of shale in eastern Kansas. The discovery included a skull with two temporal fenestrae (part of the defining characteristics of diapsids), a large orbit and teeth. It also included over 60 caudal vertebrae, 7 cervical vertebrae, the pectoral girdle, radius, ulna, fibula, and articulated tibia and astragalus. This articulation tells us a lot about the morphology and development of the reptilian astragalus and ankle joint, which is why many papers have been written on this specific aspect of the fossil remains. Manual and pedal phalanges were also discovered, allowing researchers to know the arrangement of the digits; this is actually quite important evolutionarily as digit order and retention has changed over time (some animals have presented with certain digits lost and sometimes knowing which digits were retained or lost can inform evolutionary relationships). These characteristics have helped to inform the position on the reptilian and diapsid family tree that Petrolacosaurus currently maintains. Further finds of this animal and others will help to refine that positioning further of course, but at this moment we have a good idea of where the animal is phylogenetically and what its position means for the origins of specific regions and parts of the reptilian body plan, making this an extremely important animal.

18 April 2017

Old Literature

From Reisz 1977
Some days, as we all know here, the reading list for older discoveries is very small indeed. This is of course thanks to the fact that not everything ever written has been scanned or re-typed and posted online. This is not just an ancient writings problem either; I have had difficulty getting articles from as recent as 1999 online without contacting authors directly. This is important because there are numerous articles on Petrolacosaurus and some of them are slightly older articles. Remember that the small reptile was discovered in Kansas in 1932 but was not described until 1945. There were no field notes associated with the find other than the general locality of Garnett, Kansas; approximately 50 miles south of Lawrence and the University of Kansas. Having worked on a specimen from the University of Kansas Vertebrate Paleontology collections I can attest to the mountain of field records and their sometimes cryptic nature (the specimen I looked at was given the location "locality #12" but no other information) but I have not seen any completely lost field notes in my experience. Regardless of the completeness of field notes, Petrolacosaurus has been described and assigned and somewhat fawned over for decades now as the oldest known diapsid showing transitional characters. Reisz's 1977 article re-describing this old reptile and first diapsid possesses a very iconic, though general appearing, line drawing of the skull of this reptile which could easily stand in for any and all early diapsids and might be confused by some to represent a modern lizard of some kind. Petrolacosaurus has been used to describe the evolution of not only reptiles as a whole, but also in describing the origin of one of the bones making up the ankle joint, the astragalus (known as the talus in humans). This Peabody paper from 1951 is not only interesting, but important in understanding the evolutionary origins of a bone that was important for reptiles, crocodiles, pterosaurs, and dinosaurs and birds. Petrolacosaurus is a very important animal in the history of evolution despite its small size and these papers make that quite evident. Enjoy reading them and discovering more about the origin of reptiles!

17 April 2017

Walking with Monsters

There are many animals known only from the screen for many people. Petrolacosaurus is a prominent member of this group of animals as many only know it from its appearance in the Walking with Monsters series. Despite its dinosaur-like name, Petrolacosaurus was a small reptile and, as we can see from the first clip featuring it, at the mercy of many other animals like the enormous amphibians, arthropods, and insects it was contemporaneous with. The second clip shows that not all of these interactions went poorly for Petrolacosaurus though. The small predatory reptile was the beneficiary of tragic natural events like forest fires (as shown) and was capable of running down prey smaller than itself.

16 April 2017

Know Your Early Diapsids

One of Dr. John Merck's online lectures for one of his geology classes summarizes some aspects of diapsida and specifically references the characters of Petrolacosaurus that have caused it to be assigned to the base of the diapsid family tree. Other sites have information on Petrolacosaurus as well. These include Prehistoric Wildlife which has a short paragraph describing what is known about the small reptile. A more extensive entry and probably the most comprehensive and easy to read entry outside of the Wikipedia article or a scholarly journal entry is that found on the Walking with Monsters version of the wiki sites.

15 April 2017

Dawn of the Reptiles

We have discussed the dawn of the dinosaurs, multiple times depending on the taxa discussed in any given week, the dawn of mammals, birds, amphibians, and a number of other introductory taxa. Some of these have been composed of disarticulated nearly complete skeletons and some have included single limbs or even single bones. One of the most complete purported "first" taxa is one of the earliest diapsids, a small reptile with two holes in its lateral skull wall (from which we gather the meaning of the word diapsid). Discovered in 1932, the fossil of Petrolacosaurus kansanensis (Lane 1945) comes from the Pennsylvanian age of the Carboniferous (approximately 302 MA) and includes the skull, pectoral girdle, elements of the hind and fore limbs, and a large portion, if not the entirety, of the axial or vertebral skeleton.

14 April 2017

The Artistic Crinoid

Murals and large scale paintings of ocean scenes often include Crinoids. Despite their lower population now, comparison to the Permian, these odd animals have always been prevalent members of the ocean.This level of involvement in the ecosystem makes the inclusion of such creatures in artwork almost essential, especially in panoramas of more ancient subject matter. Some good images that include Crinoids can be found at this link (some may be erased in the future, FYI). Crinoids have been the subject of professional as well as amateur art for a very long time. They have been main subjects as often as they have been background animals actually. Line drawings of Crinoids have populated the notes of scientists since before natural history was even considered a legitimate profession (scientific history is one of my favorite side hobbies and I promise that the history of natural history is very interesting). The best Crinoid-centric image I have found this evening is presented below. This image is older, as we can tell by its artist, Heinrich Harder, but is one of the best Crinoid centered images that can be found online. The image shows a variety of Crinoids, or as Harder called them "seelilien", swaying gently in a current and anchored into the sandy bottom of the ocean. The colors have faded over the years, but imagining the brilliance of the reds, yellows, and purples of the Crinoids one can really see the beauty of these strange animals from Harder's perspective.
©Heinrich Harder

13 April 2017

Forgotten but Popular

Crinoids possess a fairly simple appearance from an external view. A large stalk or stem, a calyx, and a feathery appendage are used for stability and locomotion, feeding and reproducing, and directing food into the mouth respectively. We can think of Crinoids as upside down starfish with the stalk growing out of what would be the dorsal surface of the starfish and a sucker or root-like tendrils anchoring the animal when it does not want to float on the currents. Some of these root structures are comprised almost entirely of the cirri that originate in the stalk. Their tough fibrous nature allows certain Crinoids to use the cirri as small and mostly inefficient legs as well, moving the Crinoid slowly from area to area. It is this stalk that is so often discovered by amateur fossil hunters in roadcuts in places like Missouri and Kansas; in case you find the shear number of fossils hard to believe consider these links please: (Missouri state fossil and Crinoid Stonehenge Model). The calyx is also frequently found, complete with the feathery arms, but is still not as regularly discovered as the stalk by amateurs. The calyx has, like other echinoderms, mouth, reproductive organs, and anus in close proximity to one another; if this sounds confusing, consult this graphic to the right. The feathery arms of the animal are called Pinnules and are ciliated, or covered in small hair-like structures called cilia that are capable of moving gathered food items toward the oral cavity of the animal. Crinoids add even more amazingness to their life history in that they are pentaradial echinoderms. Echinoderms are unique in that they begin life as bilaterally symmetric ("mirrored") larvae and during their life cycle grow to be pentaradial, or having five main segments arranged at 72º intervals around the mouth. Consider the ontogenetic image below to better visualize this change.

11 April 2017

Researching Crinoids

Crinoid papers are everywhere. Crinoids are everywhere. The Crinoids have been researched across time in the Lower Mississipian, and in geographic regions like the Antarctic, and the western Atlantic. Character traits of various Crinoids have been research, described, and cataloged, with specific interests apparently heavily invested in morphology (including microstructures of endoskeleton), ontogeny, physiology, and even locomotion. Topics like the Permian extinction event are given special attention as well, as it justifiably deserves considering that this event was extremely significant in the overall evolution of this class of animals. These papers are, of course, just a very select few of the the published works concerning Crinoids and do not even begin to scratch the surface, but there are far too many works to read in a single week at this point in the history of Crinoid research. Enjoy the readings presented here and, if so inclined, go beyond through your own literature searches.

10 April 2017

Living Fossil

The term "living fossil" is thrown out as a saying far more often than it ought to be used; it should almost never be used to be honest, but we cannot stop everyone from using odd phrases like that. Regardless, a documentary called Living Fossils produced an entire episode on Crinoids that is pretty well done and informational. Enjoy this video today:

09 April 2017

Fossils and Extant Crinoids

Videos of extant Crinoid groups are often given fantastic titles like "Amazing Free Swimming Feathers!" and descriptions like "mesmerizing video". These videos are not heavily inundated with facts and interesting trivial bits as we try to disseminate on Sundays, but there are plenty of dedicated websites to garner facts from. Fossil Facts, Fossil Era, and Kids Search are prime websites for reading short paragraphs loaded with all kinds of facts about these interesting animals. More official sites also present fact files and quite a few photographs of fossil specimens. These fossils come directly from Kansas, in the case of the Kansas Geological Survey and a variety of localities in teh case of the UCMP at Berkeley.

08 April 2017

Overlooked Animals

One of the most populous and overlooked animals in the ocean since at least the Ordovician is the group of over 500 extant species in the genus Articulata. Also known as Crinoids, these strange animals belong to the class Crinoidea, live in areas from the shallows to at least 9,000 m deep, and have a historical range in three additional genera (all extinct) that spans the globe leaving fossils in a large range of geographic areas and geological time zones. The fossils of these passive filter feeding animals have been found attached to fossilized driftwood, the bottoms of ancient oceans, and in lengths in excess of 40 m. As single stalked echinoderms that were enormously successful, Crinoids underwent two explosive radiations early in their evolution in both the Ordovician, when they first definitively appear in the fossil record, and during the very early Triassic, after an extinction event near the end of the Permian initially bottle-necked the Crinoid record for a short period. This second radiation lacked morphological diversity previously seen in Crinoids, but did exhibit some of the longest individuals with Pentacrinites reaching lengths of approximately 40 m (130 ft).

Given that there are hundreds of species and somewhat fewer genera, the reason that Crinoids have been lumped together for this week is because the wealth of information for any one individual species is actually quite limited, online, and there are a number that are not even mentioned anywhere online aside from acknowledgement that they existed. Talking about the entire group together we can discuss a large number of morphologies all at once and compare them. Be prepared for a lot of talk about stalks and plant-like morphologies. These are very unique animals that are often mistaken for plants. Be amazed, or perhaps underwhelmed, by their looks!
Photo uploaded by Berengi; GNU Free Documentation License, Version 1.2