Ignore the Placement

The problems with bird fossils exted far beyond the crushed and fragmentary remains that they are composed of. This fragmentary nature leads to many hypotheses of relationships and uncertain positions within the group. This includes the recently announced material related to ostriches and the fact that the tree, based on genetics, morphology, or whatever else, is in continual flux these days. That being said, we can approach our fossil for this week knowing that we are going to mention the family and genus without going into too much detail on hypothesized positions in the group. Regardless, the largest of bird genera needs very little more than itself to be intriguing enough to discuss. Having pseudoteeth also makes this giant fossil rather intriguing. Described in 1857 by Lartet, the genus Pelagornis consists of four currently recognized species; P. miocaenus Lartet, 1857, P. mauretanicus Mourer-Chauviré and Geraads, 2008, P. chilensis Mayr and Rubilar, 2010 and P. sandersi Ksepka, 2014. All four species have pseudoteeth and the wingspan of P. chilensis is estimated to be the second largest of the four at 17 feet from wingtip to wingtip. Compare this the albatross (and an eagle and  pigeon), one of the largest extant seabirds, above. The species P. sandersi is estimated to have had a wingspan at least seven feet longer (that is 24 feet folks). We can compare that to even more extant birds, because it is amazing.

Feather Your Dinosaur

There are many interpretations of Compsognathus rolling around the internet that still appear quite dinosaurian. That is to say that many of the illustrations that are on the internet are still showing tight skinned Compsognathus running around in very dinosaur-like situations and doing dinosaur-like things. However, Alexander Lovegrove and many other newer artists or artists that change their styles to match current trends in science have adopted a much more feathered look for Compsognathus. This look is very interesting for Compsognathus and seems to be quite fitting. This small family of dinosaurs wears its feathered jaguar spots quite well. The gape on what appears to be the adult is impressive, though not unrealistic at all and, for a little dinosaur, is certainly more than enough to capture small lizards, mammals, and insects. Aren't they adorable?

©Alexander Lovegrove

Popular Dinosaurs

Compsognathus is a popular dinosaur. The well preserved fossils that allow us to know so much of its anatomy also allow us to portray the dinosaur in a variety of modes including animation and as static models. These, in turn, create an even more popular image of the dinosaur. The dinosaur has been used as a model for Jurassic Park and a number of other movies and documentaries. It is the quintessential small dinosaur that can be shown with a very dinosaur-like body plan (Coelophysis not withstanding).The dinosaur has also appeared in books, popular magazines, and as toys. Most recently it has been given a role in the developing game ARK. They appear to be capable of being tamed and running around with your character. There have been less useful sidekicks.

Compsognathus' Extra Material

Nopsca 1903

The name Compsognathus means "elegant jaw" with an alternative definition of "dainty" but the dinosaur was far from fragile; though it may have been elegant. Both specimens are robustly preserved, the German specimen even more so. The German specimen is thought to contain eggs in addition to its integument preservation. A chicken sized dinosaur with well preserved skin and eggs a marvel unto itself but could certainly spawn chicken-dinosaur-egg jokes. This specimen also contains gastric contents, illuminating the diet of the small dinosaur as it was in the instant that it died. Illustrations of Compsognathus prior to the more famed illustration by Nopsca in 1903 that shows these coincidental fossils, such as that by Marsh in 1896, were recreated in the traditional dinosaur pose with the tail dragging along behind it. Both Nopsca and Marsh's illustrations are great for what they are. Marsh's illustration shows the body plan and skeleton of the dinosaur in a reasonably accurate portrayal of the bony anatomy, though not in posture, as noted earlier. Nopsca's illustration is great for showing the coincidental fossil material. Together they show a great deal of information about the dinosaur.

Marsh 1896

New Papers

Previously Compsognathus papers were discussed on this blog at the following link. Since that time other research discussing or using Compsognathus as a model taxon have been published. This is great for us because we are staying current and updating what we previously learned about our tiny dinosaur friends. These newly published studies include dinosaur reproduction (ovarian follicles and a debate about their existence). Dinosaur reproduction is always a hot topic and therefore an interesting and entertaining topic. Additionally, there are mentions of Compsognathus in new books written about the origin of birds. The mention is small but important as the discussion about the origin of birds is important information to get out to more and more people (there are many that still do not recognize that birds are dinosaurs). These comparisons are steeped in comparative descriptions of dinosaurs and birds that were published previously. To close out paper Tuesday I direct you to the Cambridge Journal Robotica. If one is not able to view the PDF on the Cambridge site, an alternate but older version of the material is available from Transactions of The Japan Society of Mechanical Engineers. This may not be as current, however, it does include images of the robot in use:

©Akama et al. 2011

Tributes of Dinosaurs

Compsognathus, as popular as the dinosaur is, does not feature heavily in any documentaries or movies. The video we showed yesterday is one of the more blatant and obvious videos that exists for the dinosaur. There are also tribute videos though. These are set to music and show images of the dinosaur, but not a great deal of information is really shared. If learning is your main goal, the WizScience video is the way to go today:

Compy Facts

Compsognathus is well known and relatively popular with dinosaur lovers. Their small stature makes them somewhat of an enigma to people that expect dinosaurs to be giant lumbering animals or even giant energetic animals. Everyone has the ability to learn something new about these animals regardless of any preconceived notions or lack thereof that one might have. A number of sites have jumped on the fact sheet train for Compsognathus and we benefit from this significantly because we have multiple outlets from which to learn about this tiny dinosaur. There are straightforward fact sheet pages like About and Enchanted Learning. There are also pages written more as essays than strings of facts. These are similar, but may be of more interest to higher level readers. These are pages like the revamped and more vibrant Kids Dinos (still home of the illustrated timeline and nifty maps) and DK's Eyewitness website. There is also this video, which we shared last time we discussed Compsognathus on fact day:

Old Friends... In Space

This is the last full week of June for blog purposes. The cosmonaut dinosaur for this month is the popular and previous discussed, at great length, Compsognathus longipes. The "elegant jaw" dinosaur was a small animal whose remains were recovered in continental Europe. The orange and green silhouettes in the scale drawing presented here are from France and Germany respectively. The remains of these French and German animals are the most extensively known and most complete skeletons attributed to Compsognathus. There have been random feet and legs attributed to the species from time to time; Sinosauropteryx, from China, has been described at least once as a species of Compsognathus. The beauty of the two skeletons is that both are complete and even integument is preserved in the fossils. The German specimen has been described as having fatty deposits preserved along the abdomen. The German specimen preserves this level of detail because of its exquisite limestone base. The French specimen is also encased in a limestone base but did not preserve integument with the level of precision that the German fossil has. There is more to discuss in the preservation of the animals and a lot more that has been inferred and hypothesized from these remains. It will be a full week of discussion to be sure.

Charlie's Shield Lizard

Scutellosaurus was a small lizard possessing dermal scutes. Many illustrations of Scutellosaurus are similar to one another for many reasons. These reasons include the small size of the animal and the prominent use of an almost sheet-like layer of dermal scutes lining the back of the animal. These scutes feature heavily in many illustrations, in fact. As one of the defining features of Scutellosaurus' lineage the scutes are important enough that this distinctive feature of the animal is acceptably pronounced in illustration. Statuary is not different at all. The statues of Charlie McGurdy are life sized and the artist strives for realism as far as is possible with fossil taxa. The Scutellosaurus piece is bipedal and well defined; however, it also appears to suffer from the common dinosaur restoration problem of extremely tight skin. Regardless, the statue is well constructed and reasonably accurate, as far as we can be in recreating the fossil animals of the past.

Walking Around

Two legs or four?Larger, later, thyreophorans are always illustrated as walking on four legs because of their immense size. There are temporary exceptions to this rule, however, as Stegosaurus is often portrayed rearing up up on two legs to get at the leaves on tall fern trees that it appears to have difficulty getting to otherwise. This is not walking, of course, but should be noted as an exception all the same. The basal member Scutellosaurus, like many basal taxa, appears to have had the ability to walk bipedally and could have been facultatively quadrupedal. This is something we commonly see in basal taxa of dinosaur families that eventually reach enormous sizes. There are many reasons that this kind of morphological occurs. Most often, as in this case, it is partly because of the small size of the basal members of the eventually enormous taxa. Scutellosaurus started off as one of those extremely small taxa and this may explain entirely why it appears to have been mostly bipedal. This could also be an artifact of the known skeletal elements.

©Jaime A. Headden

Pride of Arizona

Papers are written on a regular basis about dinosaurs from many different regions and specific states. Not many of the dinosaurs that we have discussed here include reference to Arizona. There are a few, but of those, Scutellosaurus is one of the most prolifically written about. These papers do not include the description paper but many papers from that long ago (almost 35 years ago) have not made their way to the internet and electronic hosting still. We do not expect they will be any time soon, however, there are still a number of other important papers that can be read about Scutellosaurus online. These include redescriptions of new material that is attributed to the dinosaur discovered approximately 16 years ago. Rosenbaum and Padian maintain the position of Scutellosaurus and attribute the new material to the dinosaur despite the incompleteness of the previously described skeleton. Other papers mention but do not feature Scutellosaurus. There are papers on herbivory in dinosaurs and descriptions of the thyreophoran family. Finally, it is important to note that Edwin Colbert revisited his original description and discussed Scutellosaurus in the Third Annual Fossils of Arizona Symposium. The original restoration is presented again in the portion of the paper discussing Scutellosaurus. It is an informative skeleton but the description of the material is more useful for understanding the animal. The visual helps of course.

Scutellosaurus' Other Videos

The major video showing Scutellosaurus was shared yesterday because it was oriented and aimed directly at a younger audience; older folks that enjoyed it were not wrong to enjoy it at all. There are other videos online that feature some form of the dinosaur Scutellosaurus but they are not highly informative or well animated. One video is a ten second clip from a video game but the second is much more interesting. The second is a small statue from Florida's Dinosaur World which is a small park of dinosaur statues and animatronics. The statue is most interesting because it appears life size, meaning that it could disappear easily in the ferns, much like the actual Scutellosaurus dinosaur. The statue itself is not much to look at and is not accurate beyond size really, but it is still an interesting piece of art.

Facts on Plates

Scutellosaurus is a curious little thyreophoran dinosaur. Being a small dinosaur within the base of the branch of that family, Scutellosaurus has garnered a lot of attention both professionally and from the dinosaur enthusiast community. That allows us to have a large pick of fact pages and short essays about the tiny little armored dinosaur. There are sites with simple fact files like About and Enchanted Learning. The Dinosaur Jungle site presents the same facts in paragraph form rather than as a simple listing of facts whereas Kidzsearch adds a small amount of information to the short paragraphs. Scutellosaurus also is popular enough that it has been illustrated in an episode of I'm A Dinosaur, featured below.

Before Plates

©Pavel Riha

The origins of the thyreophorans are rarely discussed, in my personal circles, but the basal members of the family are strange and interesting even before the family developed large armored plates and skeletons. One of the earliest comes from the Early Jurassic approximately 196 million years ago. The remains of the dinosaur Scutellosaurus lawleri (Colbert 1981) were recovered from Arizona by David Lawler. The early thyreophoran was very small compared to its descendants, weighing in at approximately 3.9 feet long, 20 inches tall, and about 22 pounds. Covered in primitive versions of dermal armor scutes, Scutellosaurus was a small fully armored dinosaur that was capable of defending itself against similar sized predatory dinosaurs but not significantly against larger and stronger dinosaurs that could get around the dermal armor by crunching through with high enough bite forces. Determining how strong those scutes and armors are might take more than this week but we can certainly try to get into the topic.

Dilong's Popularity

Small tyrannosaurids are popular dinosaurs for good reason. They represent what will become, or in the instance of juveniles already are, a group of enormous carnivorous dinosaurs that captivate the information. Combine the fantastic size and terror of these dinosaurs with the fantastical imagery of feathers and scales mingling across the different regions of the tyrannosaur body and suddenly we have a majestic and terrifying animal that the public loves. Smaller versions, the ancestral forms, are even more peculiar, because they are very tyrannosaurid in shape, but much smaller in all dimensions. Dilong and other base-of-the-tree tyrannosaurids also possess a slightly more generic body plan that is similar to members of earlier clades, making their mixture of tyrannosaurid and "other theropod" features curious but intriguing.

©Robinson Kunz

Feathers of the Dragon

Typically a dragon does not have feathers, but Dilong paradoxus is not an ordinary dragon and it is indeed covered in feathers. A number of skulls and apparent ontogenetic stages of remains have been recovered belonging to Dilong. The feathers of Dilong were concentrated around the skull and the tail specifically. These feathers were simple feathers potentially even protofeathers rather than full fledged feathers capable of flight. Instead, as protofeathers, these structures were more likely used to maintain body temperature. Lacking extensive display feathers, the homeostasis hypothesis is even more likely. Because of the feathering and evidence of other tyrannosaurids skin covering impressions, Xu, et al. 2004 hypothesized that all tyrannosaurids had multiple different regions of unique skin coverings. The reason we only see on in the Dilong skin impressions is because of this multifaceted regional covering and the lack of other regions becoming impressed in the fossil slab.

Describing Dilong

The description of Dilong by Xu, et al. is a short but thorough work. The paper addresses the anatomy of the fossil and provides clear photographs to go with the description as well as line drawings where needed. The burgeoning tyrannosaurid features of the skull are wonderfully detailed in the line drawings. Feathers are also discussed in the paper. A reconstruction of the present skeletal elements brings together the end of the paper just before the feather material is discussed. This paper is worth reading, and it is a short read, partially because there have been no other papers dedicated directly and solely to Dilong and also because it was written in wonderful detail and with precision.

Dilong Liked Mammals

The Science Channel had a sensationalist documentary pitting dinosaurs against mammals on air in 2007. One epsiode of that series featured small feathered theropods hunting slow and ponderous small mammals of the Cretaceous. One of those theropods was Dilong, of course, and is depicted as hunting in small packs. In the video Dilong also has a significant and respectable jumping ability, though this is not often mentioned elsewhere and may be somewhat speculative. The anatomy is well represented despite the strange leaping behavior. The inferences of a good sense of smell are regularly discussed in tyrannosaurs and have been extrapolated to Dilong, though it did possess an open antorbital fenestra, which would house the nasal soft tissues and any associated sinuses. Imaging of the brain endocast, to determine the approximate size of the olfactory bulb, has not been conducted to my knowledge. Many studies examining the sense of smell in theropods have been published that can be applied to Dilong, however.

Dilong Facts

Dilong is a popular dinosaur for a number of reasons, the least of which is the relationship between Dilong and Tyrannosaurus. Despite the distance of that relationship, tying any dinosaur to T. rex makes it automatically popular. This has translated into many fact pages on the internet. There are expected pages on sites like About and Dinosaur Jungle. There are a lot of other pages as well as WizScience (the computer scripted fact) videos that we have shared here a few times.

Despite its popularity, Dilong does not appear in a lot of other videos online. There is a documentary with the dinosaur out there somewhere, and we will try to find at least clips of it to share tomorrow.

A Paradoxical Dinosaur

The confusing nature of the small Chinese dinosaur Dilong paradoxus is probably one of the smallest dinosaurs that could have been referred to as the "Emperor's Dragon." Originally described as an early ceratosaurid tyrannosauroid Dilong is certainly a paradox. More recent descriptions of the small dinosaur have removed the proceratosaur title from the descriptive taxonomy of Dilong. Both hypothesized phylogenies place Dilong as a predecessor, an ancestor potentially, to the line leading up to Tyrannosaurus. Dilong also has the distinction of being one of the clearest visible feathered fossils that has been recovered. The original fossil is a very detailed composition of the death of this wonderful, but unfortunate dinosaur.

Type Specimen ©Kabacchi

A Forgotten First

Ten years ago Salgado and Gasparini described Antarctopelta oliveroi exactly twenty years after it was discovered on James Ross Island in Antarctica. In 1986 dinosaurs from Antarctica were not a thing. Antarctopelta constitutes the first dinosaur fossil remains recovered from the continent. A number of other dinosaurs have also been unearthed in Antarctica, including Cryolophosaurus. The majority of the fossils are even less known and more forgotten than Antarctopelta. The timing of naming the dinosaur most likely led to these circumstances; Cryolophosaurus was named eight years after the discovery of Antarctopelta rather than twenty years. Our final illustration for the week is something of a capstone on the two well known Antarctican dinosaurs. A week and five years ago Alain Beneteau was featured in a post with two drawings of Cryolophosaurus. neither of which could have included an Antarctopelta meal for the large theropod. Geography and time separated the two dinosaurs by approximately 110 million years. There were certainly food items for the theropod and predators of the giant herbivore in their respective times, but no battles played out between the two. Our final Antarctopelta of the week shows how lonely its fossils are at the moment. Much of Antarctica is still unexplored though and more fossils could be uncovered in the future.

©Alain Beneteau

Extrapolating Armor

In the Late Cretaceous nodosaurian ankylosaurs were covered with armor and many of these dinosaurs even had larger extended pectoral (shoulder) or pelvic horns that could be considered offensive weapons. It should come as no surprise that many illustrations of Antarctopelta feature not only nodosaurian dermal armors but pectoral horns. The horns that are shown in this manner are often more ornamental in appearance. The angles at which the horns extend is nearly completely vertical rather than extending in a manner that would allow for their use as offensive weaponry. In this more vertical orientation they would serve more as a deterrent if they were not entirely ornamental. Dermal scutes, like those shown, were also typical in nodosaurian armor schemes. Overall the interpretations of Antarctopelta that are available are typical of many nodosaurians; this is a result of the fragmentary remains that have been attributed to the dinosaur so far.

©"Green Mamba" (website unknown)

One Island

James Ross Island is the only site from which Antarctopelta remains have been recovered. Those remains are fragmentary and have been reported in the single description as line drawings of the individual elements of the ankylosaur. Salgado and Gasparini do not expressly mention why there are only line drawings in manuscript. The remains that exist and have been described are characteristic of ankylosaurs enough that there was little doubt of the diagnosis. Reading the paper and examining the line drawings is the best way to understand the dinosaur this week. Unfortunately, however, none of those remains are so obviously ankylosaurian that they can influence illustrations and interpretations of the dinosaur. Bearing that in mind, as you read the paper, form your own image of Antarctopelta in your mind!

All the Videos

Every video with the name Antarctopelta leads to game clips or narration over game clips from the Jurassic World game. Very few of these videos are lengthy, educational, or actually focus exclusively on Antarctopelta. A rare but commonplace (anatomically speaking) dinosaur often suffers from a lack of enthusiasm or favor from the public. Apparently, given the volume of Jurassic World Antarctopelta videos, winning, unlocking, or receiving this rare dinosaur is a feat worthy of the many guides and bragging videos about having unlocked the animal in-game. Buried in all of these videos is a single tribute video. This is shared below, odd music choice (Korn for some reason) and all, as it is the only video that is not an in-game video of the dinosaur. There is no real documentary purpose to this video, but it does show a lot of illustrations of the dinosaur, making it a nice collection of visuals if nothing else.

Kids Love the Antarctic Shield

Antarctopelta oliveri is known from a small amount of material and there is an equal, maybe even lesser, amount of material online to share with dinosaur enthusiasts of all ages. The best site is About, as usual with dinosaur fact pages. Using Wikipedia is definitely an option in this instance that would make sense. There are no videos and very few sites that have anything more information. In the case of animals with little fossil evidence and a mostly inferred body plan this lack of fact pages and videos, as we have seen in the past, is not entirely unusual. Ankylosaurs from Antarctica are unknown other than Antarctopelta, making the minor amount of fossil evidence unique and even more special. The lack of websites is alarming given that information though.

Antarctopelta Roaming

The small ankykosaur that was shown in yesterday's post was an important part of the South American ecosystem. The animal was not only a prey item for large theropods but also smaller theropods and filled an important niche as an underbrush feeder. Antarctopelta was a short dinosaur and only capable of racing certain levels of vegetation. Some illustrations show the dinosaur reaching up into the lower boughs of trees by bracing itself on tree trunks. This possibility, and other aspects of the anatomy of Antarctopelta, will be investigated during this week.

Run Carnotaurus

©Ian N. Cost

Over the week we have at least mentioned all of the anatomical anomalies (e.g. forelimbs) and anatomical craziness (e.g. horns and huge mouth) of Carnotaurus. The BBC Walking With website was kind enough to summarize most of the points we have made with a unique illustration of Carnotaurus. Their Carnotaurus looks like it is having a long day though. The illustration for the day is not the agonizing and exhausted Carnotaurus though. The illustration of the day is also not this sculpture that was featured at the Memphis Zoo's dinosaur exhibit a number of years ago. It is a very nice sculpture (and one of the most liked photos in the past of this blog actually).

©Mohamad Hagani

There are two amazing illustrations of Carnotaurus that are not commercially produced or photos taken by myself. The first is one of the most active illustrations that we have seen of Carnotaurus. In this image by Mohamad Hagani a Carnotaurus that has some feathering along the middle of back from head to tail hunting a small ankylosaur. The speed seen in the image is well portrayed and the image is captivating. The anatomy of the dinosaur looks appropriate, including the hypothetical feathers, and the dinosaurs are both animated and vividly alive. The enormous mouth of the Abelisaurid is almost dragon-like in this image but in a way that is not terribly foreign and out of place looking on the dinosaur. The feathering is tastefully added to this Carnotaurus. Instead of the last feathering we saw, this is a minimalist approach to feathering and is well done.

©Alvaro Rozalen

The second image that really captures a unique Carnotaurus image is by Spanish artist Alvaro Rozalen. Rozalen is responsible for the All Your Yesterdays cover art and is an accomplished artist. His vision of Carnotaurus is based on the description of the dinosaur as written in Michael Crichton's second dinosaur related book, The Lost World. In the novel Crichton depicted Carnotaurus as a deceptive animal that was naturally capable of chameleon-like camouflage. Rozalen shows Carnotaurus in stunning camouflage standing in front of The Lost World logo. It really kind of speaks for itself.

Classic Popularity

Popularity of theropods among dinosaur fans is usually superficially based on enormous bodies or hideous grotesqueness or some kind of ornamentation. Carnotaurus has all of those things. Some people are intrigued by the horns and other rugosities on the skull and some by the large frame or the rather large mouth. The weirdness of the forelimbs also appears to intrigue many people. The forelimbs we discussed briefly before and throughout we have talked about the big head, big mouth, and big body of Carnotaurus. The dinosaur's horns are very interesting parts of their anatomy. Many of nature's horns and rugosities are embedded in the skin or at least originate from the skin, though there are notable exceptions like horns that are bone. The horns of Carnotaurus are bone and therefore originate from the skull rather than from the skin. Those horns are sometimes flimsy in the best interpretations of Carnotaurus. Are these interpretations of Carnotaurus not the best products of the popularity of the dinosaur, flimsy horns and all?

Little Arms or Little Wings

I stumbled on Croatian artist Damir G. Martin's depiction of a rather unique Carnotaurus pair. Nowhere that I have seen has the interpretation of the small arms of Carnotaurus included wings and, with the rather well known skin impressions showing scales, feathers have not often (maybe not at all) been discussed in relation to Carnotaurus. The inclusion of feathers, small wings originating from the shortened forelimbs, and the small crest on one individual is interesting as well as novel. These theropods are not running and sprinting quickly, as one paper that we read yesterday asserted, else the feathers would be a bit more ruffled. In this image the feathering appears almost fluffy and certainly very fitting the way these Carnotaurus individuals are standing here.

The wing structures are very avian in this image. However, there are no correlated structures on the fossils like quill knobs on the ulnae. There are also no feather impressions near the arms in the fossils; there are none along the body either of course. The same lack of evidence can be stated for the head structure shown here. A structure like this could also be used, in the illustration, to assume the sex of this individual. After seeing this imagination of Carnotaurus it is almost unfortunate that we have not seen feather evidence in Carnotaurus; it looks like a very fitting (almost turkey-like) rendition of the dinosaur.

Famed Papers

Carnotaurus is a dinosaur that is relatively famous but has somehow escaped the eye of the blog until very recently. Reading this post that is self evident as this week is entirely dedicated to Carnotaurus. The amount of literature that has not been shown here about Carnotaurus is quite extensive. There are some articles, as there always are, that are more interesting or important to the study of an organism that we can single out. There are studies of the speed and general gait at which the dinosaur moved and the way in which the dinosaur used that speed to go about its daily life (its paleobiology). Additionally revealing important aspects of the life of Carnotaurus are studies about the animals head. The head is a unit of importance for feeding, mating, breathing, and basically every other aspect of being alive. We know a great deal about the dinosaur's braincase and the rest of the cranium including implications of cranial biomechanics. Probably one of the most charismatic papers discusses the forelimbs of the dinosaur. It is charismatic mostly because people are interested in the "funny looking" arms and they have been studied, described, and inferences have been made.

Cartoons and Serious Movies

Ranging from independent animated shorts like the simply titled Carnotaurus by Bennett Kim to serious feature length films, Carnotaurus is a film superstar.

In the majority of films Carnotaurus is depicted as a violent, and often, brainless carnivore with a single goal. That single goal tends to be the devouring of all life forms though that is not the case in the above Bennett Kim short. Dinosaur fandom being what it is, there are also more amateur productions such as this puppet feature by the so-called "Great Nate". We are not disparaging an amateur short like Nate's; his puppet fight is actually fairly well done and fun to watch. Most famously, Carnotaurus, was the feature villain in the 2000 animated Disney film Dinosaur. There were two animals that attempted to eat the main characters without talking or singing and dancing (contrary to many Disney movies) but they eventually were not able to eat the main characters. Sad for the villains.

Carnotaurus Facts

 

There are many ways to find information about a dinosaur as widely known as Carnotaurus. Those ways include normal fact sheets like those found at Enchanted Learning and About. The real value today is in allowing a 2nd grade student to teach his peers about a dinosaur that he likes. There is nothing quite like young enthusiasts teaching one another. Our older readers may be more interested in different videos that are a little more edited. There are plenty that are far too edited, featuring music that really does not seem to go along with the information or images that are presented in the video. We can actually follow the progression of videos through their complexity with the assumption that the video from the 2nd grade student is somewhere in the middle. The Dinosaur Feed presents a video that is all instrumental music and written facts displayed with an animated Carnotaurus. A more detailed, but somewhat editorial representation of facts is presented in this Paleo Profile video. Clocking in at nearly thirty minutes it is definitely the most detailed video.

The Weird Limbed Astronaut

©Brynn Metheney

Abelisaurids have very small arms that are even stranger than the tiny arms of tyrannosaurs. The group includes some very ornamented and very strangely armed but well known theropods including Majungasaurus and Carnotaurus. The "fleshy bull" deserves the bull part of its name as it possesses two significant and obvious bovine-like horns superior to its orbits. The fleshy part of its name refers to its diet; what else might teeth like those be used to eat? Known as a single species (C. sastrei Bonaparte 1985) from a single skeleton discovered in 1984 in Argentina, Carnotaurus is also unique for those strange and tiny arms. Shorter in proportion than even the arms of Tyrannosaurus, the arms of Carnotaurus are also rotated posteriorly at the shoulder so that the arms face the hips (to remember the direction I think of it anthropomorphic terms, like the dinosaur is putting its hands in its pockets). These hands are fairly vestigial and therefore largely useless to Carnotaurus. We will look at the horns, the hands, and the skin of Carnotaurus this week!

New Images, Maybe?

Araripesuchus is almost always shown in some sort of trotting posture. Rarely is the imagery of an Araripesuchus eating or sleeping or doing anything other than trotting. Instead of digging up some strange interpretations of Araripesuchus we should probably have a better idea of how large these animals were. The small crocodilians were not as large as their extant cousins and appear to be less frightening because of their diminutive size. The lessened scariness, based on size, is more than likely not a real thing for most people, though I am sure a few people would disagree. A small crocodilian of any kind trotting around can be quite scary.

Why Are You Famous?

The most well known of the species of Araripesuchus is A. wegeneri. Many quality specimens of this species exist and have been recovered including the block of a number of individuals interred together that was shared earlier in the week. Aside from that specimen there are a number of high quality skulls of A. wegeneri that allowed for dietary inferences to be detailed. The lower jaw is known only from the dentary and therefore does not add any information to the inferences about diet. The block, and other remains from other species, allowed for inferences about gait that painted the picture of a galloping terrestrial croc. This makes Araripesuchus look and walk much more like a mammal than a reptile.

From Sereno PC, Larsson HCE, 2008,
Cretaceous Crocodyliforms from the Sahara.

Where It Lives

Sixteen collections of Araripesuchus remains are recorded in the Fossilworks database online. Fossilworks does not have all of the collections of the fossils presented there meaning that there are more collections of the fossils not recorded online of course. The site allows one to generate timelines of occurrence and allows for maps to be generated. The plots are basic, but being able to see where Araripesuchus remains have been recovered shows us a great deal about the general distribution of the taxa before they went extinct. As we can see from the map and the timeline, the many species of Araripesuchus are widely distributed across geography and time. The majority of the recorded remains are spread across Africa during the Cenomanian age of the Late Cretaceous. A number of the remains represent book ends of their specific as they have been recovered from the Cenomanian and the Aptian age at the end of the Early Cretaceous. Proposed errors (i.e. missing fossils) are represented here as one species at least has been recovered from the Maastrichtian age which ended with the end of the Cretaceous or, as we usually refer to this time period, the K-T extinction. Assuming some error, Araripesuchus may have even lived, however briefly, into the Paleogene era as a genus headed toward extinction. Unfortunately Araripesuchus is considered to be a dead-end genus with no surviving descendants and is on the sister branch to extant crocodilians; this depends on the tree that one is consulting and if others have a more preferred assignment for Araripesuchus that they would like to share please do so!

Love for Crocodilians

Araripesuchus is a well loved group of animals, in part because there are a lot of species in the genus that are represented by a lot of remains. There are newly describe species within the genus like A. patagonicus that was first published in 2000 and A. buitreraensis described in 2005. There are also new remains that belong to previously known and described species. The most famous species was described in 1981, in German, and can still be found in the original form online. There are papers concerning every aspect of Araripesuchus' history beyond description. Among these the most common themes in paleontology are well represented as well, such as osteology and phylogeny. Conveniently these are both addressed in the same paper more than once. The most recent version of this discussion available online is from Turner in 2005. There may be newer discussions coming in the near future, but these will suffice until that time.

Lovely Sculpture

There are two videos that I am going to share today. One is a WizScience video; meaning that it is one of the computer readings of facts in video form.

The second video is, arguably, much cooler and more entertaining. This video shows a sculptor's interpretation of the soft tissues based on the cast skull of Araripesuchus. The artist is Tyler Keillor and the sculpture itself was made for the National Geographic special When Crocs Ate Dinosaurs. The other croc sculptures in the special were also created in the University of Chicago lab and, if one watches the special, you can see all of the different models.

Late Sunday Facts

Despite the level of interest in crocodile-like reptiles of the past and present, there are not a lot of fact pages online for Araripesuchus. Considering how interesting the animal is with its intriguing posture and heterodont teeth, it seems to have escaped the notice of many typical fossil fact pages. The only page that actually has a hosted fact file is About; this is probably because their writer Bob Strauss likes fossil animals as much as we do and has devoted a lot of time to putting together these fact pages.

Rule of Thumb

Generally as a rule I attempt to stay away from Crocodylomorpha not because I do not like the taxa (I actually like a lot of reptiles generally speaking) within the group but because the lab I work in has a lot of crocodilian projects ongoing and I therefore hear a lot about crocodilians on a regular basis. However, lately a rather interesting crocodylomorph caught my attention and, as it has been described since 1959, discussing this fossil genus is way overdue for people that love extinct animals but have not heard of the genus Araripesuchus. Araripesuchus consists of six accepted species: A. gomesii Price, 1959 (type), A. wegeneri Buffetaut, 1981, A. patagonicus Ortega et al., 2000, A. buitreraensis Pol and Apesteguia, 2005, A. tsangatsangana Turner, 2006, and A. rattoides Sereno and Larsson, 2009. Disregarding all discussion over validity and placement of these taxa in relation to one another and other crocodyliforms, the most interesting individiual taxon in the genus is the well known and much lauded A. wegeneri. Slabs of multiple individuals of the species and the well preserved skulls and limbs of the individuals reveal a lot of information about the species and in turn the genus. Using these specimens we know that the teeth of the animals were heterdont and imply a diet that was at least omnivorous and at most completely herbivorous. The limbs tell us that this was a terrestrial crocodyliform able to walk upright in a more mammalian posture, very unlike its extant relatives.

A. wegeneri, ©Todd Marshall

Sheer Power

Powerful giant birds have a tendency to be popular fossil animals. We can always assume that it is because the animal is a large frightening bird when we are discussing the so-called terror birds (or giant ducks like Gastornis). Andalgalornis is also popular because it is very well known and has been the subject of high profile and very informative biomechanical studies. The vignette we featured earlier from the Witmer lab, being a high profile lab, also extends the fame of the bird. Toys are non-descript, but there are at least one or two that are purported to represent Andalgalornis. Having a charismatic scientist in the lead of the studies helps also.

Frederico Degrange with Andalgalornis
Courtesy of the Museo de La Plata.

On Being Pecked to Death

Andalgalornis we have seen is a voracious predator but had a rather unorthodox style of procuring its food, in terms of giant carnivorous birds. Possessing an akinetic skull with a large dense beak, Andalgalornis was more likely to bring that beak down on prey like a heavy rock than it was to delicately grasp and kill prey. Each method of hunting has its benefits of course, but the blunt object method of smashing one's prey makes ambush slightly more useful and practical to an animal than chasing down food and attempting to crush it with one's head. This was certainly effective either way, as the giant head of Andalgalornis effectively sustained the genus for a number of years without significant alteration. Why an increasingly kinetic group of animals developed into forms without cranial kinesis is an intriguing question though.

(C)Renata Cunha

The Degrange and Tambussi Series

The Degrange and Tambussi series of papers on Phorusrhacid terror birds is not always those to authors or always in that order. The reason that the majority of papers are written by the two is that they are in the heart of terror bird country and they have an awful lot to say about the birds they have studied for so long. Those studies and results have turned out papers concerning all sorts of biomechanical analyses and results that tell us a great deal about the birds. Specifically, in the world of biomechanics, Degrange led a paper on an analysis of feeding habits and behaviors of Andalgalornis in 2010 that shed a lot of light on diet, cranial kinesis, and and the general capabilities of the terror birds of South America. In a further expansion of the dietary and behavioral capabilities of Andalgalornis Tambussi led a paper describing the flexibility of the neck of the bird. This paper includes one of my favorite behavioral inspired graphics that I have seen published. The inferred range of motion is very clearly detailed in this singular image and almost eliminates the need for the rest of the figures.

Birds in Motion

Yesterday I only shared a very short clip of Andalgalornis that was much more general and discussed terror birds as a group rather than focusing only on what we know of Andalgalornis. There are videos that discuss only this specific bird rather than drawing from many birds to generalize behavior or even anatomy. The generalizations are important, but seeing the actual actions or anatomy of any given taxon are important for understanding what makes this animal Andalgalornis. As a group (i.e. humans) one of our favorite things to see is another animal, especially fossil animals, biting things. That is certainly a part of the reason (not the whole reason I can assure everyone) that this video from the Witmer Lab was made and posted.

Biting and the actions that contribute to biting are intriguing to myself and many other people. Tracing the evolutionary history of these actions is certainly aided by viewing 3D animations of the animals that we are interested in. Here, for instance, we can see the movements, or lack of movements, in the skull of Andalgalornis. We see a similar system of akinesis in crocodilians but in extant birds there is a wide variety of kinetic capabilities including hypermobility. Seeing a bird built more like a crocodile than a parrot is quite unique.

Video Confusion

A lot of videos featuring "terror birds" are about any number of combined South American taxa. The fact pages that exist for South American taxa of giant birds get confused the same way sometimes. Discovery hosts a blanket clip about all terror birds that discusses them briefly. This is probably one of the better short generic clips that is available online. Unfortunately generic is best for today, as the more specific and single in its discussion of taxa that links are concerning Andalgalornis the more they are lacking in content.

A Killing Beak

Due to mentioning the giant bird Andalgalornis yesterday and not knowing a whole lot about that particular genus, I think it is very important that we discuss this South American terror bird in this week's posts. Andalgalornis steulleti is actually a lesser known genus of terror bird, in comparison to the other large bird fossils that have been recovered from the Pliocene rocks of the continent. This terror bird may not have been as terrible as its nearest relations, and may not even been a very fearsome predator compared to the other apex predators of the time.

©John Conway

Hunting, not Trunkless

©Andreas/Elperdido1965

The original intended image today was going to show Macrauchenia without a trunk. However, I did not hear from the illustrator and we do not put up paid artist's creations from their websites without permission, unlike much of the internet. Instead, we see the interaction of Macrauchenia as prey and a late common predator of South America, Smilodon fatalis. Smilodon emigrated across the isthmus of Panama late in the lifeline of litopternans and very late in the line of Macrauchenia itself. Prior to the introduction of Smilodon the major predators of Macrauchenia were the morphologically similar but unrelated Thhylacosmilus and giant birds like Andalgalornis. This foreign incursion of predators (bears and other cats in addition to S. fatalis), along with many other ecological factors, played their parts in the extinction of this great and singular ungulate of South America. South America, at the time, was much as Australia is now in terms of the isolation of the faunal assemblage. As with Australian isolation, the sudden introduction of exotic taxa to South America ended not only the lineages of herbivores like Macrauchenia but also carnivores like Thylacosmilus.

Famous Noses

Macrauchenia has been famous for a very long time and not entirely because the fossils were originally brought back to Europe by Darwin and the Beagle. The llama-esque body and trunk certainly added to the wonder and therefore fascination with the animal. The fascination with the animal has mostly caused Macrauchenia to become a computer game favorite. The fossil mammal has appeared in a number of zoo and Jurassic Park based games over the years and has even been recreated for Spore by users. The resemblance is acceptable at least. There are also a number of toys ranging from small plastic pieces to plush toys. That is the benefit of popularity I suppose, having a plush animal dedicated to the image of your genus. It is really for the benefit of people that love the animal more than anything of course; I think everyone understands that being popular with humanity is only good for extant animals in need of human intervention.

What About the Nose

Macrauchenia has a long flexible rostrum. The skeleton of the animal does not possess any fossilized structures that show this, however the evidence for the attachment of soft tissues corresponding to an elongated rostrum are visible on the cranium. the hypothesis that the marks indicated a trunk-like proboscis is comparable to that of saiga antelopes, which helped to develop the hypothesis and probably facilitated its general acceptance. The idea behind nostrils like that is unlike the reasons for elephant trunks and is related much more to keeping dust out of the respiratory tract of the animals. When an animal that probably avoided predators by running and kicking lives in a dusty environment it stands to reason it will have many adaptations to keeping foreign dust particles from clogging its lungs and stomach. These reasons make the saiga antelope parallelism make more sense. The diet of Macrauchenia also lends some credence to the likelihood of dust filtration rather than feeding being the primary reason for the appendage. The diet of Macrauchenia consisted of leaves and other small amounts of vegetation. However, some scientists think that the teeth of the animal were not suited to grasping leaves and assert that the trunk was therefore used for that purpose rather than primarily for filtering dust from the air.

©Olga Kobryn

Melding Posts

Mondays around here are getting somewhat sparse as we get further and further from commonly known taxa. Macrauchenia really does not fall into the "rare taxa" bracket, but videos for the odd beast are severely lacking. Rather than pushing out a post showing someone playing with toys or a ten second clip of a video game, we will go straight on into paper Tuesday. Papers and research done on Macrauchenia are much more abundant than videos and documentaries. The papers span time from its discovery and description to the present day. This time span is represented by Darwin's original description here and then jumps forward to the 1860s; Owen's description exists, but is not hosted online. Darwin thought that the fossils belonged to a giant camel resembling a llama in overall shape. Macrauchenia was well known by the time Huxley named a second species from Bolivia (M. boliviensis) in 1861. In 1865 a revisiting of the dental formula of Macrauchenia by Owen also survived from that decade. The redescription was originally a rebuttal but prompted a more in depth redescription in 1870 by Owen that focused entirely on the dental formula and teeth of the animal as seen in the lower jaw. Owen was particularly interested in describing the molars of the lower jaw in this paper. I cannot find the description of the third species and Cope does not mention a third species in his 1891 summary of the Litopterna. He does mention that M. patachonia is the size of a mule and M. boliviensis is smaller. Most of the summary is concerned with dental formulae again, as are many mammal fossil papers. More recent papers exist on the subject of Macrauchenia and the family Macrauchenidae with the latter receiving more attention as these recent studies contain more overall descriptions of what ties these animals together in a taxonomic family.

Macrauchenia Facts

Being one of a select few, relatively speaking, ungulates of South America, Macrauchenia is a very interesting animal. Beyond that, it is also interesting because the original fossils were originally recovered by Charles Darwin during his expedition on the HMS Beagle. Darwin and the Beagle carried the fossils back to Sir Richard Owen who described the fossil in 1838. This fact is discussed in many places, but the only fact page that uses the story prominently is About. Other pages, instead, discuss Litopternans and more about the anatomy and hypothesized life history of Macrauchenia more. There is also this short video on the interactions between the newly migrated-to-South-America saber toothed tigers and the on-their-way-out Macrauchenia.

 

The Long Llama

Some fossil animal names mean rather strange things. The name Macrauchenia patachonica carries the meaning "Long llama of Patagonia." The fossils of this long nosed evolutionary end have been found only in Patagonia. The geographic limitation of the fossil may be due to the fact that Macrauchenia represents the last South American ungulate and last member of the litopternan order. Litopterans were odd-toed animals of South America possessing three toes most often, but one group reduced their toes to a single digit, much like horses. Macrauchenia and its order arose independent of other ungulates and lasted until the end of the Pleistocene. The dental battery of 44 teeth aided the animal in being highly successful, as did a lack of large predators. The largest predators at the time would have been the last of the terror birds of South America and the smilodon-like Thylacosmilus, which we have discussed before. Another unique feature of this animal was its trunk-like nose and camel-like body.

Changing Face of Pterosaurs

Albert Gaudry

The understanding of pterosaurs has come a long way and also foundered in many ways throughout history. Generally speaking the original impression of pterosaurs was one of bat-like morphology as bats and birds were the only vertebrates known to naturalists that first described and discussed pterosaur biology. Scaphognathus appears in many older texts as a bat-like pterosaur with odd looking petagium like elements stretched between the body and wrists/ankles. There may have been some skin elements between these structures and arguments have been fiercely made for the ankle to tail connection in particular. These connections are not necessarily incorrect and there may be some evidence in other pterosaurs for the structures; I actually have seen no such evidence as yet in Scaphognathus but would certainly not rule out the possibility. There are, additionally, many hypotheses of the purpose of these structures in pterosaurs. We do not need to get into those hypotheses at this moment.

Not Too Popular

Scaphognathus is a popular small pterosaur, but it is not so popular that it is a household name or readily recognizable by many. The pterosaur appears in a number of places and is used as a base for models in games because of its fantastic fossilization. This does not translate to wide ranging popularity however. The popularity it does enjoy mostly comes from the Jurassic Park Facebook game and Jurassic World tablet game. The games include a somewhat odd interpretation of Scaphognathus showing it clambering up trees and gliding short distances only to fall slowly to the ground (see the video below at 1:35). Assuming Scaphognathus was not capable of powered flight and had to glide, this is correct; however, assuming its diet was considerably populated by small fish makes the short gliding distances unlikely to have benefited the animal. A diet of mostly insects, as briefly mentioned earlier in the week, could be obtained with short glides like this more readily than a diet of fish requiring longer gliding times. References to the slab fossil in books on pterosaurs and as an exemplar of the Solnhofen also appear in relation to the pterosaur; this is mentioned in passing typically as Archaeopteryx is more often lauded when the Solnhofen is discussed due to its notorious fame.

Days or Nights

Small pterosaurs ruled the skies until birds took flight and edged them out. They did this much as birds do now; during the day and night and all hours in between. Many of the smallest pterosaurs discovered and described from the Triassic and Jurassic have been examined thoroughly and they have been described alternately as being dirunal or nocturnal based on the sclerotic rings that remain in the fossilized crania. Sclerotic rings encircle the eyes and their size can be correlated with the missing soft tissues. The overall size of the eyes, orbits, and sclerotic rings all allow for inferences about the lifestyle afforded by the eyes of the particular pterosaur in question. The eyes of Scaphognathus indicate that the pterosaur was diurnal. The similarities between Scaphognathus and the contemporaneous taxa Rhamphorhynchus and Ctenochasma also lend themselves to inferences of the time of day in which the animals were active. Rhamphorhynchus and Ctenochasma are hypothesized to have been mostly or strongly aligned with a nocturnal lifestyle. Similar diets shared between the three taxa living different lifestyles makes niche partitioning a likely scenario. Seeing fossil ecology put into practice in this way is not frequent, but when we do get to paint that sort of scenario it is special and quite intriguing.

©Dmitry Bogdanov

Many Tales of Wings

Scaphognathus at more than one time (seven times total) was synonymized with other pterosaurian remains. Always remaining the oldest specimen, however, means that the name Scaphognathus remains the name that we know today. Considering that Goldfuss first described Scaphognathus in 1831it is not hard to believe that it is the oldest of the synonyms. One of the latest descriptions that was given the name Scaphognathus actually was determined to be distinctly different and was therefore renamed Parapsicephalus. Some of the descriptions attributed to Scaphognathus and strange unknown sights may have led to the very interesting and highly implausible cryptozoological assertion that Scaphognathus was alive and flying in the 17th century. It was stated that archaeology and science backed up the idea that the animal was alive and that the initial description of Goldfuss was based on a somewhat recently deceased individual, compared to other fossils. I share the paper making these assertions only because it is important to see the difference between science and speculation. The paper mentions evidence based on 17th century drawings and stories, but there is no actual evidence pointing to live pterosaurs during that time. Instead, we have descriptions of the fossil that are anatomically correct and scientifically skeptical; that is, the experimentations and protocols followed to produce the work have a heavy weight of evidence behind them. These include a number of articles but the best paper on Scaphognathus entirely is a description of the cranial morphology of a specimen that was recovered from the Solnhofen of Germany in 2014, the first place that a fossil of Scaphognathus was recovered. This description was informed by the 2004 paper, also by Bennett, detailing what was ten years prior new insights on an older specimen of the genus.

Movie Supplies

Movies are in short supply for pterosaurs. The movies that exist for Scaphognathus are short and most of them are related to the Facebook game that is sponsored, in name at least, by the legacy of Jurassic Park. There is one video that is not related to the Jurassic Park game. That video is a fact video with computer narration from WizScience. We have seen that group of videos produced and posted many times. They are good videos in terms of facts, but the computer generated voice can be a little grating and its flat narration has very little intonation. The monotone can be a little boring, but there is something to be learned in the video.

Flights of Facts

There is a strangely light amount of reading in the fact department where Scaphognathus is concerned. The small pterosaur does not necessarily require a great deal of fact pages. There are definitely enough facts on Prehistoric Wildlife's page on Scaphognathus. The KidzSearch encyclopedia has almost no facts on the page unfortunately. The Jurassic Park wiki makes up for the other online encyclopedia by presenting a fair amount of information and a number of illustrations.