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.

The Kimmeridgian Boat Jaw

Senckenberg Museum of Frankfurt

The Kimmeridgian, often associated with the Solnhofen limestones of the Late Jurassic, is the area most often associated with high quality slab fossils of thin and small boned dinosaurs from Germany. Multiple specimens of a certain pterosaur, Scaphognathus crassirostris, have been recovered from this deposit. The generic name refers to the blunt boat-like appearance of the mandible whereas the specific epithet refers to the wideness of rostrum. Scaphognathus was an early pterosaur and was overall of diminutive size (skull = 4.5 inch, wingspan = 3 feet) with long needle-like teeth well adapted for grabbing insects on the fly. The teeth were well preserved in the skull of the holotype and, with additional specimens of the cranium as well, we know that there are 16 teeth in the upper jaw that overbite the mandible and that they are all vertically oriented. Fish catching early pterosaurs possessed diagonally and horizontally oriented sets of teeth. The holotype is a well preserved and articulated specimen that has not, like so many pterosaur fossils, been flattened thoroughly.

August Goldfuss, 1831

Life Intervenes

It is unfortunate that the past two days have seen no new posts concerning Dakotaraptor. The dromaeosaur has not been forgotten or pushed aside but other events and goings on were slightly more relevant than revamping a pair of months old posts. That said, I should schedule in a time to write so I do not put off days of writing these posts, even if the animal from the calendar was recently an animal on the blog anyway. Friday is image day now with the new schedule, though, and with a popular dinosaur images are changing and being uploaded almost daily because artists appear to be enamored with the large dromaeosaur still. An artist we have not seen around here lately, possibly because I have simply not looked at his page for a while, is Tuomas Koivurinne. Mr. Koivurinne has always been a favorite (because of his style and interests in dinosaur and military themes) and in the early days of the blog was featured very regularly. His interpretation of Dakotaraptor is probably one of the most dark portrayals in content and composition that is available for viewing online. To be honest, the color scheme involves a lot of cool but light colors, the darkness of the image in relation to other Dakotaraptor images online is due to the minimal sky influence on the image. Many of the images available are on white backgrounds or feature a more open terrain. The closest composition of images are those that we have seen from Emily Willoughby, but I would argue that her Dakotaraptor, while appreciably fierce, appears to be much more huggable than this rather raptorial version. I think that the image dichotomy between the two illustrators and their work emphasizes the fact that this was both a feathered and fluffy looking dinosaur (an argument could be made for the huggability of Koivurinne's Dakotaraptor also) and a carnivorous and potentially highly active predator. Similar view points are seen in the way that people view eagles, hawks, and falcons today as animals that look somewhat soft because of their feathers but tend to also respect their capability to produce violence to procure food. Dakotaraptor may have appeared fluffy and cuddly but it was a vicious predator and Koivurinne's artwork here captures that aspect of the animal's life perfectly while remaining quite safe for work and, I would argue, for sensitive audiences.

©Tuomas Koivurinne

Tapping Out

Normally I would never do this, but the only two papers that exist on Dakotaraptor appeared in the last paper post. Therefore, here is a link to the last post!

Movies for Dakota

Somehow we have not managed to run out of videos for Dakotaraptor. The dromaeosaur was big in life and has been big as a fossil so far. Its impact is more prominent because it is a "raptor" of extraordinary size. This is shown in the video that we are sharing for Movie Monday. Despite its popularity it is not featured in any documentaries, yet. This may change in the near future, but not at this moment. We do have more quality narrations and news stories though, and that is quite useful.

Dinosaur George has, since the last time Dakotaraptor was here, has posted a video answering questions on the dinosaur. We have not shown Dinosaur George posts in a while, and that is entirely because I have not come across them lately, not for any other reason. He seems like a nice guy and he values education. I am okay with him.

This Time

Last time on fact day I posted most of the same websites that still exist. Posting them a second time would be redundant and there is no need to do that. Besides, there was really only one or two that was worth posting. There was a rather good dinosaur fact video on Dakotaraptor and there were a few that I skipped over. Instead of posting old material, here are a couple of the fact videos that are acceptable, but that were passed over last time for one reason or another:

Revisiting a Recent Raptor

In the somewhat recent past we discussed a large dromaeosaur of the middle north of the United States. That dromaeosaur is was recently discovered and described and is named Dakotaraptor steini. This is the last full week of April and Dakotaraptor is the calendar dinosaur for the month of April. To refresh the reader's memory, Dakotaraptor is one of the largest North American dromaeosaur discovered to date and was recovered from South Dakota's Hell Creek formation. This formation is Cretaceous in origin and Dakotaraptor is from an area of the formation that correlates to the youngest rocks and therefore the end of the Cretaceous. Throughout the publication and popularizing of the description of Dakotaraptor the paleoartist Emily Willoughby has portrayed the dinosaur time and again. This illustration is the only illustration of hers that was not featured the last time that Dakotaraptor was the dinosaur of the week. She posted this little sketch on Twitter and it is absolutely adorable.

©Emily Willoughby

Size and Andrewsarchus

How large is the purported largest terrestrial carnivore that ever lived? Andrewsarchus mongoliensis had the largest carnivore-like skull known for a terrestrial animal. At approximately 3 feet long, the skull is absolutely massive for a carnivorous animal, as we see them today. A modern adult tiger has a skull measuring 1.3 feet in length. A tiger is a large predator. Andrewsarchus was a nearly 3 times larger predator, if we assume the body estimate is allometric with the skull. Artistic interpretation of the size estimates of Andrewsarchus look something like this, which is quite impressive:

Popularity and the Pig-like Beast

Andrewsarchus may not have been related to pigs, but the fact that it resembled a pig and still does in most modern illustrations may be severely confusing to some. The depiction in the most popular place that Andrewsarchus has been shown was even slightly rotund. The Walking With Andrewsarchus is large, muscular, and intimidating. That is a trend that continues in other illustrations as well. The strangest thing about Andrewsarchus' popularity is that it has blossomed in less opular venues than television, books, toys, movies, video games, and other highly visible areas. Instead, it has something of a nearly cult-like following on the internet. Amateur illustrations, professional illustrations, and fan sites are all populated with Andrewsarchus. Thankfully Andrewsarchus managed to be illustrated on one of the informational cards that we see now and again that is so vibrant and fearsome.

Superb Skull of A Gigantic Beast

The remain of Andrewsarchus consist of a single Mongolian skull from a presumed adult specimen. The skull is not a complete cranium and is lacking the mandible. This means that we do not know anything from solid evidence about the dentition of the lower jaw. The assumptions that are considered when looking at possible stand ins for the lower jaw include similarly built carnivores and members of Andrewsarchus' branches of the mammalian family tree. Simply put, this means that we have to consider whales, hippos, and small extinct mammals of the family Raoellidae. An assumption exists, regardless of the model taxon used to inform the mandible, that the teeth belonged to a strict carnivore. Contention in the field crew existed over this idea with Roy Chapman Andrews asserting that the 3 foot long skull belonged to a great predator and the chief paleontologist (Walter Granger) attributing the skull to a giant pig, essentially calling it an omnivorous beast of great size. No one disagreed on the great size, whatever their view of the diet. The known dentition is respectable and fearsome in the 3 foot skull. The dental formula is 3 incisors, 1 canine, 4 premolars, and 3 molars. This is the exact dental formula of extant pigs. That explains Granger's suspicions of the phylogenetic position of Andrewsarchus. Hippos have the same formula, with some variation, which backs up Chapman's assertions. Recent evidence has also reinforced Chapman's position rather than Granger's, but we cannot argue that he had a valid reason for being suspicious of the origin of the beast we know as Andrewsarchus.

Relationship Problems

The closest living relatives to our giant predator is a giant herbivore. This has happened many times in the history of life and as such it is not remarkable in terms of being a revelation. However, Andrewsarchus is actually considered the sister taxon to whales and small mammals known as Raoellidae (Geisler and Theodor 2009). Spaudling, O'Leary, and Gatesy (2009) were slightly less confident with the single skull but upheld the close relationship with whales and hippos. Instead of asserting a solid relationship at a single node, Andrewsarchus is placed in a polytomy with a small group of other fossil taxa. Ignoring phylogenetics and discussions of sister groups, the initial description by Osborn is online. I always urge people to read initial descriptions and that initial description is hosted right here.

Movie Mayhem

Andrewsarchus is a small but significant documentary star. Featuring in no feature length movies, the animal does play a significant part in a television documentary. As with many of the animals we have videos where they feature, this is another instance of the Walking With series showing an animal that we are interested in. The series covered, after their very well received initial dinosaur series, the time before and the time after the dinosaurs. The Eocene predator Andrewsarchus was contemporary with the large Brontotherium, but actually has only been found in Mongolia. The Walking With series places these Mongolian predators in the same habitat as the North American Brontotherium. Obviously this is not currently backed up by any evidence, but the potential could exist given the correct conditions and there may have been other brontothere like herbivores living in Mongolia.
Walking with Beasts - Brontotherium vs Andrewsarchus (Audio Remake) from Israel Barber on Vimeo.

Sites to Avoid

Andrewsarchus makes an appearance on a number of websites. Some of those are not exactly the kinds of sites that we want to get facts from. Therefore, ignoring the message boards with dinosaurs hypothetically fighting one another, the best fact pages are the only ones left (this makes sense to everyone I imagine). There are encyclopedia entries like that at Kids Search that is very short and not very thorough but also very thorough sites like About. About's site is now, or at least for this single animal, divided into individual pages for each part of the entry. There is an entry on Dinosaur Jungle that is also well written. It does feature a very wolf-like Andrewsarchus at the top of its page, which is very incorrect, but an understandable mistake. Prehistoric Wildlife is more of a fact file than an encyclopedia article. Instead of the normal Prehistoric Wildlife images at the top of the page, only the skull is featured in the size comparison. This skull is illustrated and looks really nice, it is an interesting size comparison image.

Roy Chapman Andrews' Champion

When Henry Fairfield Osborn named Andrewsarchus mongoliensis in honor of Roy Chapman Andrews, he did not realize how long it would take for the general public to recognize and love the truly strange fossil mammal. Andrewsarchus was an artiodactyl (related to giraffes, bison, and similar animals) which makes it even more intriguing when one finds out that Andrewsarchus was a voracious predator. This assertion is based on the single known skull which sports a snout totaling about 60% of the entire skull. That snout is loaded with sharp mammalian teeth. Osborn compared that snout and skull to a number of other carnivores in his initial description. Osborn also declared that the skull of Andrewsarchus belonged to the largest terrestrial mammalian carnivore ever. It may have been.

Not so Popular

Amazonsaurus is popular for being a rare find in northern Brazil and it is also popular for containing enough material that it could be diagnosed to a genus. Amazonsaurus, for these reasons, is not very popular at all. Being represented by such a minuscule amount of material, Amazonsaurus is largely ignored by the general public because it is largely ignored by the scientific community as well. Not much can be said for a large sauropod that looks and acts like a sauropod because we cannot hypothesize much more on the anatomy with the overall lack of anatomy. People do like to draw the dinosaur though. Some of the anatomy is based on Diplodocus of course, so they are really drawing a different dinosaur mostly, but the level of detail here is still fairly phenomenal.

What Do You Look Like

The problematic part of fragmentary fossil remains cannot be narrowed down to a single area of study. One thing that certainly suffers is our capability to interpret what an animal looked like as an entire organism. This has further implications in that body shape and size can tell us a lot about how an animal lived, how it may have eaten, how much it ate, and many, many more things. The knowledge of functional morphology of an animal outweighs simply having quality accurate illustration as it tells us what the dinosaur actually did, and looked like as well, with the anatomy that it had to work with. Fragmentary fossil skeletons therefore rely heavily on identification to a group from what is available and then that another animal in that group has had enough fossil remnants collected to inform us to make an educated decision about what the new and fragmentary dinosaur may have looked like. Amazonsaurus contained enough fossil skeletal elements that its affiliations as a sauropod and more specifically as a diplodocid have been accepted after description. We have been able to fill out the missing anatomy with informed hypotheses based on Diplodocus and other members of the group. One thing that has been estimated based on our knowledge of the fossils and its cousins is the size of Amazonsaurus. Extrapolating from the vertebrae and pelvis by comparing the number of elements and the sizes of elements with other dinosaurs we have estimated the length and height of Amazonsaurus. The sauropod was not a titanosaur but it was a notable sauropod, achieving a size slightly larger than an elephant and appreciably longer. Many illustrations of Amazonsaurus out on the internet show the tail coiled up or gently whipping around. This is a tie back to the relationship with Diplodocus, and may or may not have actually been indicative of the manner in which Amazonsaurus held its tail. To appreciate the overall length, at any rate, the tail has to be straightened out.

Honorable Mentions

Amazonsaurus makes appearances in many studies and summarizing papers where it is discussed in relation to whatever other sauropod or animal that they were compared to. The only paper that is really worth reading today is the description of the fossils that were recovered and given the name Amazonsaurus. The description paper  includes line drawings and pictures of the fossils, images of the locale, and maps of the region where the fossil was discovered. Description of the geological setting is included as well, which is important for determining the setting in which the dinosaur lived, in addition to other particulars about the dinosaur and its fossil environment.

Brazilian Dinosaurs

Amazonsaurus has a 45 minute documentary that tells all about the dinosaur from discovery to description and beyond. The only problem with it is that the entire documentary is in, I am fairly confident but would be willing to admit that I was wrong, Brazilian Portuguese. The first half of the documentary is shown below. The second half is linked from the first on YouTube and after the first half ends.

Non-Portuguese speakers have a more limited choice of documentaries that they can both watch and fully understand. These are shorter and less informational. They include entries like the one below. Though not an actual documentary, it affords some information that can be used, if one can escape the robot voice without turning it off.

The Amazing Amazonsaurus

Amazonsaurus is not a very complete dinosaur. It is, though, well known as a very rare dinosaur from northern Brazil. That gathers a considerable following somewhere on the account of the scarcity of the fossils if nothing else. This has led to an appreciable amount of information available online. These sites range from short fact pages consisting of only a few lines of text to a short but well constructed series of paragraphs detailing the life history and diet of Amazonsaurus. As always, there are middle of the road pages that are easily accessible to readers of the high elementary to middle school level; groups that are at the heart of dinosaur fandom.

Adding More to the Long History

©Luiz Fernando

This week we are literally adding a longer entry into the annals of Dinosaur of the Week. There are a lot of sauropod remains in the fossil record and we have discussed many of those remains (honestly, we have gotten to the point that some of the dinosaurs we discuss have very little material actually being discovered. Amazonsaurus maranhensis is one of the few sauropods remaining that we have not discussed that has an appreciable amount of fossil material attributed to it. The vertebral column of the back and tail are fragmentary but more intact than the pelvis. The number of elements is small, but attributable to a sauropod and the only dinosaur material discovered in the state of Maranhão in northern Brazil identifiable to a genus or species.  Two unidentifiable theropods, an unidentifiable sauropod, and Amazonsaurus are known from the Itapecuru formation in Maranhão. Not much is known about the dinosaur, but it has been assigned to a group of diplodocid sauropods from the Cretaceous known as Rebbachisaurid.

Heads and Tails

To start discussing the body in more skeletal detail, the tails of Dilophosaurus are well known. The holotype animal is actually quite nearly complete. This is somewhat rare for large fossil animals, though Dilophosaurus is still somewhat small by dinosaur standards. This is what allows for the inferred skeletal elements of Sinosaurus however and we do benefit from the completeness of one dinosaur in comparison with a second dinosaur. Sinosaurus, though, has a well preserved skull in a few specimens and a juvenile specimen is included in that number. The juvenile skull, and a number of the adult skulls, are disarticulated. Disarticulation can be a very beneficial outcome of fossilization; a well articulated fossil skull is good for showing a complete entity whereas the disarticulated skull can be used to show how bones of the skull are sutured and put together into the solid structure.

Sinosaurus cranial elements are well known because of all of these specimens. This allows us to identify individual bony elements and differentiate them from other animals (aiding in justification of separating the genera/species). The teeth of Sinosaurus are also helpful in this matter. These teeth are serrated on both the anterior and posterior edges and flattened width-wise. This means that Sinosaurus' teeth are actually somewhat shark-like in their construction and would cut flesh on biting down and pulling back and away with the teeth. Those inferred actions are more closely related to animals like the dromaeosaurs with recurved posterior serrated teeth. Sinosaurus had recurved teeth as well, making the comparison worthwhile, but the anterior serrations are much more useful for cutting into flesh during the powered closing of the jaw. The anatomy appears to indicate the idea that Sinosaurus was biting and cutting its prey at the same time and then pulling and making a second cut as its teeth were moved away from the prey. That sort of wound would be hard for any animal to recover from and might explain some hunting hypotheses related to these animals.

Sinosaurus Shown Complete

One of the positives of being similar to another fossil animal is that that fossil animal's skeleton can inform missing and destroyed elements of the animal that it is comparable to. Sinosaurus therefore benefits from relatively more complete Dilophosaurus skeletons and vice versa with a little bit of guesswork involved where required. Many times the fossils we collect from any given species or genus are related to the cranium and there is very good reason for this. A key element in the process of fossilization is the fact that larger, more solid objects have a regular tendency to fossilize better (for many many reasons that are better left for a different discussion). The cranium tends to be one of the larger, more solid, objects that many animals possess; clams and other hard shelled fossil animals as well as fossilized plants benefit from related but different circumstances. This all has a lot to do with what we know about Sinosaurus. This dinosaur exists mainly as a number of well preserved skulls with some fragmentary skulls and postcranial skeletons added into the mix for good measure. These are not the kinds of "wow-factor" remains that typically interest the public to the point that we see children's books and stuffed animals. The fact that Sinosaurus has a morphological doppelganger that is much more well known from Jurassic Park does not help to spread the word about the dinosaur; the general public tends to equate anything remotely like one dinosaur as that dinosaur unless expressly corrected, there is no shame in not knowing your dinosaurs!

Casually Walking

Early theropods did not need to be as enormous as Tyrannosaurus for a number of reasons, chief among them being that their prey was not nearly as large as the mega-sauropods and ceratopsians of later ages of dinosaurs. Sinosaurus was still a long predator but possessed a much more gracile body than many following theropods. The dinosaur was definitely still well muscled and had the teeth to terrorize contemporary prey items; however, it is unlikely that it was generating the bite forces of Allosaurus or Tyrannosaurus. Sinosaurus may have rivaled and even outraced the other two dinosaurs, based on the gracile body, but tests of this sort of hypothesis has not been conducted on Sinosaurus so we cannot do more than speculate. The body of Sinosaurus is estimated to have been approximately 5.6 m (18 ft) long, making it shorter than the similar-in-appearance Dilophosaurus which measures 6 m (20 ft) long. Dilophosaurus, which appears in the fossil record a few million years prior to Sinosaurus was probably the largest carnivore in its ecosystem, if not globally, at the time and Sinosaurus may have held a similar distinction. Aside from being the largest animal, a large portion of the length of Sinosaurus (as in Dilophosaurus) was made up of tail.

©Dmitry Bogdanov (as Dilophosaurus sinensis, jr. synonym)

As we know from dromaeosaurs and hadrosaurs a long stiff tail is a great counterbalance for running. However, the tails of Sinosaurus specimens does not appear to be stiffened and instead appears to be appreciably flexible instead. All of the largeness and gracility to this point has pointed to a terrific carnivore outpacing and overshadowing all of its prey items. A flexible tail, though, points less toward high speed running, so it is possible that despite appearing capable of producing significant speed (in relation to other dinosaurs) Sinosaurus may not have needed speed or it may not have required a stiff tail for specific counterbalancing; that is, it may not have accelerated or sustained speeds in the same way that later stiff-tailed dinosaurs did. There also exists the possibility that there was not a great amount of speed at the command of Sinosaurus and its gracile frame and appearance of potential speed is, like its similarity in appearance with Dilophosaurus, merely an impression of a character that we have attributed to it hypothetically, but falsely.

Teeth, Tracks, and Crests

Sinosaurus has left its mark across much of China and a great deal of paleontology that has been published from China. The literal mark making is documented in trackways, though these are rare (compared to those in North America) and are not completely diagnosable. To that end, a small number of theropods are discussed whenever trackways are found. Sinosaurus has found its way into those discussions as a stand in (literally) foot model for some theropods and as a contributor to these trackways. Xing et al. 2014 discusses both of these possibilities in regard to newly discovered trackways in central China. Trace fossils of predators are typically represented either by the trackways above or by lost teeth. The benefit, to us and theropods, of lifetime tooth replacement is that we can find fossilized teeth and theropods never have to go hungry. Whenever teeth fall out, the bone that holds those teeth remodels as new teeth grow in. This loss and remodeling is the subject of a description of the process using a specimen from the Lufang Basin in Xing et al. 2013. Traumatic tooth loss and feeding are discussed in terms of the remodeling of alveolar areas of the mandible and maxillae. In terms of the crests part of the title, many descriptions of the crests of Sinosaurus have been published. The crests are discussed in a cooperative article from American, Chinese, and Canadian paleontologists that looks at the mechanical capabilities of these crests. This may sound a little odd, however, finite element analysis (FEA) to test the crest's capability to resist loads during intraspecific combat. This use of crests has been hypothesized many times, but FEA has not been used often to test the capabilities to resist mechanical loading and to test combat hypotheses.

Weird Video List

The videos associated with Sinosaurus are as few in number as the fact pages. There are a number of good papers, but that will come tomorrow. Today there are only a handful of videos that are worth sharing. Partially because Sinosaurus is a mostly forgotten dinosaur, these videos are showing skeletal displays or self-made models rather than anything that was made for movies or anything else of that nature. In the movie department, though, we have the fact file videos of WizScience, which are typically well done but narrated by the very robotic Microsoft Word voice. All of the other videos that we find online are actually people somehow missing the letter p when spelling Spinosaurus. It appears to be a bit of an epidemic actually.

Confusion and Facts

Sinosaurus has confused many people over the years. The fossil is not entirely to blame; evolving phylogenetics have pushed apart Sinosaurus and its morphologically similar cousin Dilophosaurus. However, the visual similarity of the two has caused many to equate the two or infer a close relationship where none exists. Many pages have gotten this straightened out over time and correctly identify the familial relationships of Sinosaurus (which is more closely related to Cryolophosaurus than it is to Dilophosaurus) as they point out relevant facts about the dinosaur. The fact pages concerning Sinosaurus are few in number and that makes for a short post, sadly.

More Chinese Lizards

Any dinosaur with Sino- in the genus or species has a history of some sort that is related to or originated in China. That, of course, is important given that this week's dinosaur is very prominently related to China by name and location of recovered fossil remains. Sinosaurus triassicus Young 1948 is a dilophosaurid theropod with a number of specimens representing it. We know there are multiple not because they are all published, but because at least a secondary set of remains was named as Dilophosaurus sinensis Hu 1993 and synonymized in a subsequent study of the remains conducted by Dong Zhiming in 2003. The many different remains are housed in numerous museums including the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) and Lufeng Dinosaurian Museum (ZLJT). The reason that realizing that there area respectable number of Sinosaurus fossils in museums is important is because this is a dinosaur that is not popularly well known but is well known in science in part due to the number of specimens. 

As stated earlier Sinosaurus is a dilophosaurid. Dilophosaurid is not a recognized clade, but describes a group of crested theropods that superficially resembles the dinosaur Dilophosaurus wetherelli. Prior classifications place Dilophosaurus closer to the Tetanuran theropods (stiff-tailed theropods) to which Sinosaurus belongs. Dilophosaurus actually sits outside of even the Tetanurans in the same group as Coelophysis, making it a basal theropod. Therefore, despite superficial resemblances, Sinosaurus is actually a more advanced and derived theropod. The specific name, triassicus, refers to the fact that Chung Chien Young originally thought the formation from which the type specimen came was Triassic. We now know that Sinosaurus, like Dilophosaurus, was actually an early Jurassic dinosaur dating to between 200 - 190 million years ago.

Differences in Dinosaur Heads

©John Sibbick

Hadrosaurs of all shapes and sizes have unique features, as we know for any given taxon, and many of them sport some sort of crest above their heads. Strangely, considering the prevalence of crests, there are very few illustrations dedicated to displaying the differences between the crests and the hadrosaurs that sport them. The most well known of those hadrosaurs include the most well known crests (e.g. Corythosaurus, Parasaurolophus) in the ornithischian world. Descriptions of the Lambeosaurus crest should be fresh in everyone's mind from yesterday and the Lambeosaurs in the above illustration should therefore stick out fairly well. However, if the description alone was not enough to help a casual observer pick between Lambeosaurus and Corythosaurus please turn your attentions to this second image that shows both dinosaurs and labels them clearly.