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Panphagia, the Oldest-Known Sauropodomorph Dinosaur

For decades, South America has been regarded by paleontologists as the place where dinosaurs originated. It is here that we have our clearest record of what the oldest dinosaurs looked like. Specifically, Brazil and Argentina hold the record for the countries that possess the oldest-known dinosaur fossils. Based upon the fossils that have been uncovered in Brazil’s Santa Maria Formation and Argentina’s Ischigualasto Formation (in particular a locality known as “the Valley of the Moon”), dinosaurs are believed to have appeared during the middle of the Triassic Period about 235-230 million years ago.

Prior to the appearance of dinosaurs in the middle Triassic, smaller dinosaur-like animals scurried about within the jungles of South America. These proto-dinosaurs are known as “dinosauromorphs”. They first appeared during the early Triassic Period, and continued into the late Triassic, well after dinosaurs had appeared and established themselves. Probably the most well-known of these early dinosauromorphs is Lagosuchus, a small reptile about the size of a chicken. What made Lagosuchus and its kind different from the other reptiles which were around at the time was the fact that Lagosuchus and its close relatives ran around on two legs instead of four. This would be a major innovation which would be exploited by the earliest dinosaurs.

File:Marasuchus.JPG

The skeleton of Marasuchus, an advanced “dinosauromorph” from Argentina, dated to the middle Triassic Period about 235 MYA. It has been hypothesized that Marasuchus and Lagosuchus are in fact the same animal. Photograph by Michelle Reback (July 28, 2008). Public domain image, Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Marasuchus.JPG

For a long time, our idea of what the earliest dinosaurs looked like was shrouded in mystery. However, it seemed that the first dinosaurs were carnivores. From the 1950s until the very early 1990s, creatures like Staurikosaurus of Brazil and Herrerasaurus of Argentina were the oldest-known dinosaurs, and they were also believed to be the most evolutionarily primitive. Still, despite their supposedly archaic nature, these were fairly large animals – Staurikosaurus reached 6 to 8 feet long, and Herrerasaurus was even bigger, reaching 12 feet long. Both of these animals, and Herrerasaurus in particular, clearly would have been formidable competitors to the other carnivorous four-legged reptiles which were alive at the time. This was quite an upgrade from small chicken-sized creatures like Lagosuchus, which had existed only a short time earlier. Considering the very short time difference between the appearance of small creatures like Lagosuchus and the subsequent appearance of large meat-eating dinosaurs like Herrerasaurus, it appeared as though one of two options applied here: either dinosaurs managed to evolve into a large size within a very short length of time, or there was some intermediate species which hadn’t been discovered yet. Was it possible that there was another dinosaur, as yet undiscovered, which could fill the gap between the primitive dinosauromorphs and creatures like Herrerasaurus?

In 1991, the skeleton of a new dinosaur was discovered in Argentina by Dr. Ricardo Martinez, a paleontologist from the University of San Juan. This animal was far smaller, and it seemed more primitive, than Herrerasaurus. It measured only 3 feet long, and it appeared to have an anatomy which was less advanced than either Staurikosaurus or Herrerasaurus. In 1993, the animal was named Eoraptor, “the dawn thief”. For nearly two decades, this little animal held the title of being the oldest-known dinosaur.

However, complications arose. A closer examination of the skeletons of both Herrerasaurus and Eoraptor created doubts as to whether or not Eoraptor really was the oldest and most primitive dinosaur ever found. For example, the fewer sacral vertebrae an animal has, the more primitive it’s believed to be. Eoraptor possessed three sacral vertebrae, but Herrerasaurus had only two. This indicated that Herrerasaurus, despite being five times larger, was actually more primitive than Eoraptor. Another point of contention was the structure of the lower jaw. When Eoraptor was first discovered and described, it was believed that it possessed a less-evolved jaw structure than Herrerasaurus, but this turned out to be false. Gradually, concerns began to be raised that Eoraptor, despite its small size, was actually not as primitive as it first appeared to be. Special attention was given to the skull and the teeth. Eoraptor possessed different kinds of teeth in its mouth, indicating that it was an omnivore. A close examination of both the skull structure and the teeth made some wonder if Eoraptor was as primitive as we initially believed. In fact, there were some aspects of its anatomy that bore a bit of a resemblance to the sauropodomorph dinosaurs – the long-necked long-tailed creatures that we typically associate with the word “dinosaur” – rather than the fleet-footed meat-eating theropod dinosaurs.

In 2011, Dr. Ricardo Martinez (the same man who had found Eoraptor’s skeleton in 1991) re-classified Eoraptor as a primitive sauropodomorph. This claim was met with skepticism by the scientific community. In a subsequent study, Martinez changed his mind again and stated that Eoraptor was so archaic that it could not be placed into any definite group of saurischian dinosaurs and ought to be placed at the very base of Saurischia. However in 2013, Dr. Paul Sereno did his own evaluation of Eoraptor’s skeleton and concluded that indeed it was a primitive sauropodomorph, distantly related to other prosauropods like Plateosaurus and Anchisaurus. Even so, the overwhelming majority of the scientific community has refuted this claim. Numerous studies have been conducted on Eoraptor since it was discovered and named, and most of them state that Eoraptor is either a very primitive theropod dinosaur or else it is the earliest saurischian, appearing before the saurischians split into theropods and sauropodomorphs.

All of this raises an interesting question. If Eoraptor was not the earliest sauropodomorph, then what was?

In 2006, Dr. Ricardo Martinez was once again exploring the middle Triassic rock layers of the Ischigualasto Formation, dated to 228.3 million years ago, when he found another skeleton. It looked similar to Eoraptor, but it was noticeably larger, measuring 4.25 feet (1.3 meters) in length; Martinez thought that the skeleton was of a juvenile, and that the adult would be larger, say perhaps 6 feet long. The skeleton was incomplete, including only a partial skull. Teeth were only found in the lower jaw. The skull was clearly similar to Eoraptor’s, but it also showed some features which can be seen in very primitive sauropodomorphs like Plateosaurus. For example, the lower jaw curves downwards towards the front, which is a tell-tale feature of that group. The teeth were also very similar to those seen in prosauropods. Based upon the skull structure and the shape of the teeth, this animal seemed to be more closely related to sauropods than theropods. In 2009, the animal was named Panphagia, which is ancient Greek for “eats everything” in reference to its supposedly omnivorous diet.

Reconstruction of the skeleton of Panphagia protos. Photograph by Eva Kröcher (December 5, 2010). Creative Commons “Attribution Non-Commercial Non-Derivative 3.0 (US)”, GNU Free Documentation License (GFDL), and Free Art License. https://commons.wikimedia.org/wiki/File:Panphagia_fossil_DSC_6168.jpg.

A complete skull was not found with the skeleton, but we have enough of the bones to give us an idea of the skull’s outline. Below is an illustration that I made of what the complete skull of Panphagia might look like, based upon what was seen in the photograph that you see above. The drawing was made with a black Crayola marker.

Skull of Panphagia protos. © Jason R. Abdale (February 9, 2021).

Based upon this skeleton and the description that Ricardo Martinez and Oscar A. Alcober gave in their paper on this animal, I have reconstructed what the entire animal might look like. The creature bears a slight resemblance to prosauropods like Plateosaurus and Anchisaurus. No hands were found with the specimen. However, the illustration which accompanied Martinez and Alcober’s paper showed Panphagia sporting hands with four fingers, although the fourth digit was so small that it was probably incorporated into the wrist and wasn’t seen on the outside. The fingers themselves were longer the more distal they were to the body (in other words, the middle finger was longer than the thumb, and the pinky was even longer than the middle finger), and this was repeated in the skeletal reconstruction seen above. Since this was the reconstruction seen in both sources, I incorporated it into my own illustration.

I think that there are two issues with the illustrated reconstruction of Panphagia’s skeleton seen in the scientific paper and in the physical reconstruction seen in the photo above. Firstly, I think that the tail is too short. The animal looks conspicuously front-heavy, and the tail ought to be longer to give it better balance. Secondly, I believe that the hand structure is incorrect. Prosauropods like Plateosaurus, Massospondylus, and Anchisaurus had hands with five fingers and large thumb claws. However, it must be noted that all three of those species came from the late Triassic and early Jurassic Periods, nearly twenty to thirty million years after Panphagia’s appearance, and their hand structure may have been more evolved than that seen in archaic animals like Panphagia. However, until a more complete specimen of this animal is found, I think my reconstruction is going to remain as it is.

My drawing was made with No. 2 pencil on printer paper.

Panphagia protos. © Jason R. Abdale (February 14, 2021).

 

For more information, please read Martinez’ and Alcober’s paper on this animal, which you can see here:

Martínez, Ricardo N.; Alcober, Oscar A. (February 16, 2009). “A basal sauropodomorph (Dinosauria: Saurischia) from the Ischigualasto Formation (Triassic, Carnian) and the early evolution of Sauropodomorpha”. PLoS ONE, volume 4, issue 2. Pages 1-12. doi:10.1371/journal.pone.0004397.

https://storage.googleapis.com/plos-corpus-prod/10.1371/journal.pone.0004397/1/pone.0004397.pdf?X-Goog-Algorithm=GOOG4-RSA-SHA256&X-Goog-Credential=wombat-sa%40plos-prod.iam.gserviceaccount.com%2F20210301%2Fauto%2Fstorage%2Fgoog4_request&X-Goog-Date=20210301T093333Z&X-Goog-Expires=3600&X-Goog-SignedHeaders=host&X-Goog-Signature=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.

 

Keep your pencils sharp, everyone.

 

Some Morrison Formation Sauropods: Apatosaurus, Barosaurus, and Diplodocus

Hello everyone. Here are some simple sketches of three Late Jurassic sauropod dinosaurs from the Morrison Formation of western North America: Apatosaurus, Barosaurus, and Diplodocus. All three of these sauropods are members of the family Diplodocidae, which includes the eponymous Diplodocus and any other sauropod that’s more closely related to Diplodocus than to any other sauropod group. The “diplodocids”, as these species are sometimes called, are distinctive for having long peg-like teeth in the fronts of their jaws (good for raking and stripping, but not well-suited for biting), a nares (the hole in the skull that contains your nostril openings) that’s located on the top of the skull, and long tapering whip-like tails.

The first is Apatosaurus louisae, which measured around 75 feet long. Like all diplodocid sauropods, Apatosaurus had a long whip-like tail, but it also had a massive thickly-built neck. Some paleontologists hypothesize that Apatosaurus used its neck in whacking contests during the mating season like modern-day giraffes. You can read more about that here.

Apatosaurus louisae. © Jason R. Abdale. May 11, 2020.

 

Next is Barosaurus lentus, which measured around 85 feet long. This animal was made famous by the impressive display in the entrance hall of the American Museum of Natural History in New York City. Notice that the neck and the tail are almost the same size; the tail is only slightly longer.

Barosaurus lentus. © Jason R. Abdale. May 11, 2020.

 

Finally is Diplodocus carnegii, which measured around 90 feet long. For a long time, this animal held the record as the longest dinosaur ever, until it was challenged by Supersaurus, Seismosaurus (which is almost certainly another species of Diplodocus), and various titanosaurid sauropods from South America. Of all of the diplodocid sauropods, Diplodocus itself had the longest tail. Some have speculated that the long ribbon-like tails of Diplodocus and its kind were used like whips, and it was even calculated that they could be cracked like a modern-day bull-whip. In the early 1990s, a partial skeleton of a Diplodocus-like dinosaur was found in Howe Quarry, Wyoming which had preserved skin impressions, including a series of keratin spikes similar to those seen on the back of an iguana lizard. An article was published about this discovery in 1992, which you can read here, although it wasn’t expressly stated within the report that the creature in question was indeed a Diplodocus. However, many paleo-artists ran with the idea anyway, and it was even incorporated into the 1999 BBC television series Walking With Dinosaurs. Since this is the prevailing trend, I decided to outfit my Diplodocus razorback-style as well.

Diplodocus carnegii. © Jason R. Abdale. May 11, 2020.

 

Next is an image showing a size comparison between Apatosaurus (75 feet), Barosaurus (85 feet), and Diplodocus (90 feet). For some people, it can be difficult to mentally grasp the size and the anatomical differences of these animals just by looking at numbers on a page. Perhaps by looking at this picture, you can truly appreciate the differences in the size proportions. Apatosaurus is a muscular beast. Barosaurus looks like a see-saw with legs. Diplodocus‘ tail measures three-fifths of its whole body length. So, as you can see, not all sauropods are the same.

A size comparison between Apatosaurus (75 feet), Barosaurus (85 feet), and Diplodocus (90 feet). © Jason R. Abdale. May 11, 2020.

Keep your pencils sharp, everyone.

Haplocanthosaurus: An Enigmatic Sauropod from the Late Jurassic Period

Introduction

The sauropods are the definitive image of the dinosaur. Almost always, whenever one hears the word “dinosaur”, the image of the long-necked long-tailed four-legged behemoth is what immediately springs to mind. The sauropods were the dominant land herbivores during the Jurassic Period of the Mesozoic Era, and some of our best specimens come from western North America.

In the Rocky Mountains, in the states of Utah, Wyoming, and Colorado lies a massive swath of Jurassic-age rock known as the Morrison Formation. Here are found fossils of some of the most well-known and iconic dinosaur species, names that everyone knows, like Allosaurus, Ceratosaurus, Apatosaurus, Brachiosaurus, Stegosaurus, and Diplodocus. The Morrison Formation was home to a myriad of different species, and not just dinosaurs either. Other prehistoric creatures that have been found in this rock layer include pterosaurs, crocodiles, turtles, lizards, frogs, fish, mammals, and even insects.

While there are a few dinosaur names that stick in people’s memories, the Morrison Formation was home to many dinosaur species. One of them, which is largely unknown by the general public, was a sauropod called Haplocanthosaurus. Part of the reason why this animal doesn’t have the same caché to its name as other Jurassic giants is because it is known from only partial remains, its fossils are extremely rare, and because it is found in the oldest layers of the Morrison Formation, far below the fossil-rich layers of the middle and late strata that have yielded thousands of finds. This article will be an overview of this mysterious and curious, but not quite forgotten, sauropod of the Late Jurassic.

 

Discovery, Localities, and Dating

In the very early 20th Century, the remains of a sauropod dinosaur were found about eight miles north of Cañon City, Colorado, and they were discovered and excavated by one Mr. W. H. Utterback. In early 1903, John Bell Hatcher gave these bones the identification of Haplocanthus priscus, “the ancient simple spine” (1).

However, Hatcher soon learned that the name was already used for a prehistoric fish, and so later that year, he re-classified the dinosaur as Haplocanthosaurus, “simple-spined lizard”:

“Dr. C. R. Eastman has very courteously called my attention to the fact that the generic name Haplocanthus recently proposed by me for a new Sauropod dinosaur from the Jurassic deposits near Canyon City, Colorado, is essentially preoccupied, Agassiz having employed the name Haplocanthus for a genus of fishes. I would therefore propose the name Haplocanthosaurus for this genus of dinosaurs with simple median spines on the anterior dorsals and posterior cervicals” (2).

Later that same year, Hatcher published a lengthy and detailed description of all of the bones assigned to this new genus (3).

In fact, Hatcher was mistaken – the name Haplocanthus wasn’t already occupied after all. According to the rules of the ICZN, the original name would have been the correct one to use, except that nobody had called this creature by that name since its discovery. A proposal was submitted in 1989 to have Haplocanthosaurus as the accepted name of this creature due to its common use and the fact that Haplocanthus was not acknowledged by the paleontological community. The request was approved in 1991, and Haplocanthosaurus became the definite name of this dinosaur genus (4).

In 1954, the Cleveland Museum of Natural History really wanted a large grand dinosaur skeleton to put on display, just like the ones that were on display at the American Museum of Natural History in New York City and the Carnegie Museum in Pittsburgh. So an expedition was sent out west to bring back an attention-grabbing huge dinosaur skeleton. The expedition was led, surprisingly enough, by a college undergraduate student named Edwin Delfs (5).

Their first destination was Dinosaur National Monument, located near the Utah-Colorado border, and they hunted for fossils around that area. Unfortunately, they didn’t find anything. However, the team received a tip from some geology students from Louisiana State University that they ought to check out a site in Garden Park, located near Cañon City, Colorado. (6).

Delfs and his teammates relocated to the suggested location, and on the eastern bank of Four Mile Creek, they hit paydirt. Here were the grandiose fossils that the Cleveland Museum was looking for. However, they couldn’t dig anything up yet. The United States had entered the Atomic Age, and due to the Red Scare of the 1950s, the country was manufacturing hundreds of atomic bombs every year. In order to fuel this doomsday machine, the military needed massive amounts of uranium. Many of the fossils that had been discovered out west during the post-WWII years had been discovered accidentally by people who were prospecting for uranium deposits. Due to all of the uranium deposits in the area, Edwin Delfs first had to file a mining claim on the site before he could dig up any fossils (7).

Over the course of three digging seasons, Delfs and his team chipped away at the stone. Part of the reason why it took so long was due to the extremely hard consistency of the rock that the bones were found in. Another reason was that sudden flash floods would completely flood the excavation site, and unfortunately some of the bones were washed away before they could be saved and prepared. After three years of on-off excavations, the team uncovered a large number of vertebrae and parts of the hip. The specimen, which was substantially bigger than Haplocanthosaurus priscus, was named Haplocanthosaurus delfsi by Dr. Jack McIntosh (who is widely regarded as the greatest sauropod expert EVER) and Dr. Michael Williams who served as the curator of vertebrate paleontology at the Cleveland Museum of Natural History. The jacketed bones were brought back to the Cleveland Museum to be prepared. The skeleton was put on display, and it remains one of the main attractions at the Cleveland Museum of Natural History, where it is affectionately known by the nickname “Happy” (8).

There are currently two species of Haplocanthosaurus known to science: H. priscus and H. delfsi. Both of them are known from comparatively few remains in relation to other late Jurassic sauropods. No complete skeleton has ever been found, and there are numerous bones missing from all known specimens, including the skull; no Haplocanthosaurus skull has ever been found, which makes it difficult to precisely place this species within the dinosaur family tree. So far, we have large chunks of the neck and backbones, a shoulder blade, a few vertebrae from the base of the tail, the hip bones, a few leg bones, and that’s it. Most fossils of this animal have been found in Colorado, but one specimen was found in Montana and was nicknamed “Big Monty”. However, this specimen was found on private property, and it is in the hands of a professional fossil collector and dealer (9).

Fossils of both species of Haplocanthosaurus are found in the early and middle levels of the Morrison Formation, although it is rare within both of those levels. It is completely absent from the late Morrison. It is possible that Haplocanthosaurus lived during the latest part of the Middle Jurassic and therefore straddled the boundary between the Middle and Late divisions. However, there are so few places within North America where Middle Jurassic rocks are exposed, and the number of fossils from those rocks has been aggravatingly miniscule. So, the question of whether or not Haplocanthosaurus was a Middle Jurassic leftover that survived into the earliest parts of the Late Jurassic cannot be answered yet (10).

 

Anatomy

Haplocanthosaurus is distinctive for vertebrae that have only a single dorsal neural spine as opposed to the double-pronged V-shaped dorsal neural spines found in the diplodocid sauropods like Apatosaurus and Diplodocus. It is this anatomical feature that earned it its name “simple-spined lizard”. The neck vertebrae of Haplocanthosaurus have proportionally small centrum disks, high neural arches, a tall dorsal neural spine, and transverse spines that stick out directly sideways. Haplocanthosaurus is also noted for having femur bones that are substantially longer than the shin bones. This hints that Haplocanthosaurus was a very slow-moving animal (11).

Size measurements are difficult to pin down, because paleontologists currently recognize two species of Haplocanthosautrus: H. delfsi and H. priscus. It appears that Haplocanthosaurus priscus measured only 50 feet long, making it the smallest sauropod yet found in North America, while Haplocanthosaurus delfsi measured 70 feet long. This distinction was not known until 1988. John Foster states that H. priscus likely weighed around 23,000 pounds (10,500 kilograms) while H. delfsi weighed 46,200 pounds (21,000 kilograms). The aforementioned size measurements mean that Haplocanthosaurus priscus was one of the smallest – if not the smallest – sauropod found within the Morrison Formation (12).

 

Phylogeny

Haplocanthosaurus is a bit of an oddball as far as sauropods go because paleontologists haven’t quite made up their minds as to how to classify it. Because Haplocanthosaurus is known only from partial skeletons, deciding where it fits within the sauropod cladogram has proved problematic and aggravating, and paleontologists have repeatedly shuffled this genus around according to their own perceptions.

Due to the shape of its vertebrae, which were unlike those of more advanced sauropods, John Bell Hatcher surmised that Haplocanthosaurus must be a quite primitive. In his initial research paper, he described Haplocanthosaurus as most closely resembling Morosaurus, a name that is now recognized as a junior synonym of Camarasaurus. Since we now classify Camarasaurus as a member of the sauropod group Macronaria, a group which contains species known for having boxy heads and large nostrils, it can be inferred that Hatcher would have placed Haplocanthosaurus in that group as well (13).

Except that Haplocanthosaurus wasn’t included in Macronaria alongside Camarasaurus and Brachiosaurus. It was, instead, included in the family Cetiosauridae. The cetiosaurs were a group of sauropods that are associated with the Middle Jurassic, especially in England, India, and China. One reason why Haplocanthosaurus’ designation as a cetiosaur stuck around for so long was because of the shape and size of the leg bones. Cetiosaurs are characteristic for having femurs that are noticeably longer than their fibulae and tibiae. However, some members of other sauropod groups also have unusually long femurs, so this anatomical feature is not 100% diagnostic towards cetiosaurs (14).

From its discovery until the middle 1990s, the established convention was that Haplocanthosaurus was a cetiosaurid. And then, things began to change. During the middle 1990s, paleontologists began to take a new look at sauropod phylogeny, and many felt that Haplocanthosaurus had been misplaced on the sauropod tree. In 1998, Jeffrey Wilson and Paul Sereno proposed that Haplocanthosaurus might indeed be a primitive member of Macronaria, which is closer to what John B. Hatcher was hinting at in 1903. In 1999, Jose Bonaparte proposed that Haplocanthosaurus was unique enough to warrant a family of its own, which he named Haplocanthosauridae, but this idea was not accepted by the majority of paleontologists. In the early 2000s, it was suspected that Haplocanthosaurus might actually be a very primitive member of the super family Diplodocoidea. A survey conducted in 2005 by Mike Taylor and Darren Naish failed to definitely establish where this genus ought to be placed. John Foster, the author of Jurassic West, postulated in his 2007 book that Haplocanthosaurus was either a cetiosaur or a primitive macronarian. As the 2000s transitioned to the 2010s, the idea that Haplocanthosaurus was likely a primitive diplodocoidean began to gain acceptance within the paleontological community, and this is what most paleontologists now consider Haplocanthosaurus to be (15).

Because Haplocanthosaurus possesses anatomical features found in both sauropod families, it’s possible that it is a transitional species, a “missing link”, between the cetiosaurs of the middle Jurassic and the diplodocids of the late Jurassic. However, proving such a statement is problematic because of the rarity of finds attributed to this genus. Haplocanthosaurus is known from several partial skeletons, but no skull has ever been found. That’s too bad, because a complete skull would probably settle the argument of where this genus fits on the sauropod tree.

Below is a drawing that I made of Haplocanthosaurus. Because no skull has ever been found, I decided to make a sort of half-cetiosaur half-diplodocid design. The short keratinous scutes that run along the middle of its spine are a reference to such spines (longer ones at that) being found in association with diplodocid sauropods; if this was a primitive member of that family, I’m guessing that such spines would be shorter, if it possessed any at all. The tail is somewhat shorter than what you might expect, more in keeping with a cetiosaurid than a diplodocid. The drawing was made on printer paper with a No. 2 pencil.

Haplocanthosaurus delfsi. © Jason R. Abdale. June 21, 2020.

 

Conclusion

Due to the scarcity of remains, theories about Haplocanthosaurus’ appearance and phylogenic relationship to other sauropods are largely conjectural. Museum mounts depicting Haplocanthosaurus, such as the one in Cleveland, are composites of known finds and educated guesswork. In terms of cladistics, the in-vogue assessment is that Haplocanthosaurus is a very archaic member of the super family Diplodocoidea. However, this might change in the future depending on any new finds that are uncovered. All that we can hope for is that we keep looking, and hopefully we’ll be able to uncover some more specimens of this mysterious and intriguing North American dinosaur in the years to come.

 

Source Citations

  1. John Bell Hatcher (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 1-2).
  2. John Bell Hatcher (1903). “A new name for the dinosaur Haplocanthus Hatcher”. Proceedings of the Biological Society of Washington, 16 (1): 100).
  3. John Bell Hatcher (1903). “Osteology of Haplocanthosaurus, with description of a new species, and remarks on the probable habits of the Sauropoda and the age and origin of the Atlantosaurus beds. Memoirs of the Carnegie Museum, 2: 1–72).
  4. John R. Foster and Mathew J. Wedel (2014). “Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison Formation (Upper Jurassic) near Snowmass, Colorado”. Volumina Jurassica, 12 (2): 197).
  5. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  6. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  7. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  8. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  9. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”; “Is Nate Murphy Holding a Dinosaur for Ransom?”.
  10. John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Page 200.
  11. John Bell Hatcher (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 1-2; John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Page 200; “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  12. John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Pages 200-201.
  13. John Bell Hatcher (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 2.
  14. David Lambert, The Dinosaur Data Book: Facts and Fictions about the World’s Largest Creatures. New York: Avon Books, 1990. Page 65; Don Lessem and Donald F. Glut, The Dinosaur Society Dinosaur Encyclopedia. New York: Random House, Inc., 1993. Page 208; Gregory S. Paul, The Princeton Field Guide to Dinosaurs, 1st Edition. Princeton: Princeton University Press, 2010. Pages 173-177.
  15. Jeffrey A. Wilson and Paul C. Sereno (June 15, 1998). “Early Evolution and Higher-Level Phylogeny of Sauropod Dinosaurs”. Memoir (Society of Vertebrate Paleontology), 5: 1-68; Jose F. Bonaparte (1999). “An armoured sauropod from the Aptian of northern Patagonia, Argentina”. In Proceedings of the Second Gondwanan Dinosaur Symposium, National Science Museum Monographs #15. Y. Tomida, T. H. Rich, and P. Vickers-Rich, eds. Tokyo. Pages 1-12; Mike P. Taylor and Darren Naish (2005). “The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda)”. PaleoBios, 25 (2): 1–7; John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Page 188; John A. Whitlock (April 2011). “A phylogenetic analysis of Diplodocoidea (Saurischia: Sauropoda)”. Zoological Journal of the Linnean Society, 161 (4): 872–915; Emanuel Tschopp, Octávio Mateus, and Roger B. J. Benson (2015). “A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)”. PeerJ. 2015; 3: e857; “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.

 

Bibliography

Bonaparte Jose F. (1999). “An armoured sauropod from the Aptian of northern Patagonia, Argentina”. In Proceedings of the Second Gondwanan Dinosaur Symposium, National Science Museum Monographs #15. Y. Tomida, T. H. Rich, and P. Vickers-Rich, eds. Tokyo: 1-12.

Foster, John. Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007.

John R. Foster and Mathew J. Wedel (2014). “Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison

Formation (Upper Jurassic) near Snowmass, Colorado”. Volumina Jurassica, 12 (2): 197–210. https://sauroposeidon.files.wordpress.com/2010/04/foster-and-wedel-2014-haplocanthosaurus-from-snowmass-colorado.pdf.

Hatcher, John Bell (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 1-2. https://www.biodiversitylibrary.org/page/2345230#page/118/mode/1up.

Hatcher, John Bell (February 21, 1903). “A new name for the dinosaur Haplocanthus Hatcher”. Proceedings of the Biological Society of Washington, 16: 100. https://www.biodiversitylibrary.org/page/2345230#page/118/mode/1up.

Lambert, David. The Dinosaur Data Book: Facts and Fictions about the World’s Largest Creatures. New York: Avon Books, 1990.

Lessem Don; Glut, Donald F. The Dinosaur Society Dinosaur Encyclopedia. New York: Random House, Inc., 1993.

Paul, Gregory S. The Princeton Field Guide to Dinosaurs, 1st Edition. Princeton: Princeton University Press, 2010.

Taylor Mike P.; Naish, Darren (2005). “The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda)”. PaleoBios, 25 (2): 1–7

Tschopp, Emanuel; Mateus, Octávio; Benson, Roger B. J. (2015). “A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)”. PeerJ. 2015; 3: e857. Published online on April 7, 2015. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393826/.

Whitlock, John A. (April 2011). “A phylogenetic analysis of Diplodocoidea (Saurischia: Sauropoda)”. Zoological Journal of the Linnean Society, 161 (4): 872–915. Published online on January 12, 2011. https://academic.oup.com/zoolinnean/article/161/4/872/2732063

Wilson Jeffrey A.; Sereno Paul C. (June 15, 1998). “Early Evolution and Higher-Level Phylogeny of Sauropod Dinosaurs”. Memoir (Society of Vertebrate Paleontology), 5: 1-68.

Inverse. “Is Nate Murphy Holding a Dinosaur for Ransom?”, by Jacqueline Ronson (July 5, 2016). https://www.inverse.com/article/17806-sauropod-dinosaur-discovery-montana-fossil-hunter-paleontology-nate-murphy.

YouTube. ExtermCentral. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017” (November 12, 2017). https://www.youtube.com/watch?v=-NWL7pjrPbI.

Head-Butting, Face-Biting, and Tail-Whacking: Dinosaur Intra-Species Combat

The image of Nature “red in tooth and claw” is a compelling vision which appeals to the popular imagination. Time and again, paleo-art illustrations depict dinosaurs and other prehistoric animals actively engaged in fighting, hunting, and killing. It’s a well-known fact that violence sells, and it’s also a well-known fact that the animal kingdom can sometimes be very brutal. But was the Mesozoic world really a landscape of perpetual violence and bloodshed with animals constantly engaged in the savage business of survival?

Most naturalists, biologists, and animal behaviorists today would say “probably not”. Animals do not engage in a perpetual brawl-fest with each other. Even so, animals do have violent interactions, not only among different species (inter-species combat), but also within the same species (intra-species combat). The dinosaurs were no exception to this, and we have many pieces of evidence that individuals within certain dinosaur species engaged in violent behavior towards each other.

Before I get into the particulars of the paleontological evidence, it’s important to establish some ground rules as to the sort of intra-species combat that animals engage in today, and what the dinosaurs likely engaged in during the past. Physical combat between individuals or at least physical harm inflicted by one individual upon another is typically rooted in either social or environmental causes. Animals hurt each other for a variety of reasons, but seldom is it done purely for the hell of it – only people do that. Social reasons for intra-species combat include violence associated with mating and with mate selection. Bighorn sheep rival males cranially collide with each other until one contestant or another gives up. Other individuals within numerous animal species fight each other in order to assert their right to mate. Mating-based violence can also include some very rough love – some males within certain shark species will actually bite the females in order to assert their power over the female. Speaking of this, asserting dominance is also one of the main causes for intra-species violence, regardless of whether or not mating is involved. This involves dominance within a hierarchy system, such as a lion pride or a wolf pack. Other reasons for intra-species combat are environmental, and are usually tied to the availability of food and other resources. Territorial defense in a strong motivator in this behavior, and this is strongly tied to yet another reason, which is competition of food.

Now that we have established some of the motivating factors behind why modern animals hurt each other, let’s examine the sort of intra-species combat that dinosaurs would have engaged in. For instance, many animals will kick either out of aggression, self-defense, or purely to express annoyance. One dinosaur that possibly engaged in combative kicking was the late Cretaceous ornithopod Parksosaurus. This small speedy herbivore possessed unusually long scythe-like claws on its feet. One may hypothesize that Parksosaurus engaged in kicking contests like in cockfights, or like the modern-day Australian cassowary bird. Then again, Parksosaurus could have also used these long claws for better traction when running, like the cleats on a runner’s shoes, or could have used them like digging tools to scratch into the dirt to search for food or water.

Of course, when people imagine kicking dinosaurs, the first thing that likely pops into their minds are the “raptor” dinosaurs, such as Deinonychus, Velociraptor, and Troodon. Did raptor dinosaurs, with their killing claws, do the same? The large hook-shaped toe claws were certainly used for a specific function, either ripping prey open or pinning it to the ground. I can easily imagine two bird-like raptors squabbling with each other and kicking out with their feet, like a pair of roosters, but this is purely speculative as there is no hard evidence for raptors engaging in kicking each other.

Acheroraptor. © Jason R. Abdale. July 16, 2014.

Years ago, it was proposed that another meat-eater, the late Jurassic carnivore Ceratosaurus, could momentarily balance itself on its thick tail like a kangaroo and kick out. However, this idea has since been disproven. In order for this kicking behavior to work, the tail has to be very thick and muscular and at the same time be very flexible. Ceratosaurus’ tail was deep, but thin in cross-section, more like a crocodile’s tail than a kangaroo’s. Furthermore, it only had limited up-down flexibility. For the most part, the tail was held stiff for balance, and its range of flexibility was largely confined to side-to-side motion, not up-and-down.

Ceratosaurus. © Jason R. Abdale. April 23, 2012.

Ceratosaurus is famous for having a prominent horn on the end of its nose, hence its name. However, the horn was very thin and blade-like in form, and was certainly used for display rather than offensive action. However, there were dinosaurs and other animals in the past that likely used their heads as weapons. “Head-butting”, when animals engage in combat by using their heads as hammers, possibly occurred in earlier animals, such as the dinocephalians of the Permian Period. They had thick flattened skulls, and either pressed and shoved against one another or might have collided cranium against cranium. The dinosaurs which are most associated with head-butting are the marginocephalians, “the wide skulls”, the group that includes pachycephalosaurs and ceratopsians. At first glance, their skulls seem to have been specially designed for head-on physical combat. The eponymous Pachycephalosaurus had a rounded skull that was a solid foot thick, and many scientists have automatically assumed that such skulls were used in head-butting contests, like with modern-day bighorn sheep. A recent study by the University of Wisconsin has found that 20% of pachycephalosaur skulls exhibit head trauma, suggesting with some certainty that the pachycephalosaurs did indeed engage in head-butting behavior.

Pachycephalosaurus. © Jason R. Abdale. October 19, 2013.

But what about the other members of the marginocephalians? The ceratopsians, “the horned faces”, which include the likes of Triceratops and Styracosaurus, have also been assumed to have been highly combative animals, with their spikes, horns, and frills. In recent years, the idea of these horned behemoths duking it out with each other or impaling predators on their sharpened horns has come under intense criticism. Many of their frills are dominated by wide holes which served to lighten the weight but also made them practically useless for protection. Some scientists think that the frills and horns were primarily there for display and species recognition, and their use in defense was only an afterthought.

Chasmosaurus. © Jason R. Abdale. March 31, 2016.

As you’ve probably seen by now, most of the animals which have physical features that can be used in combat are herbivores. Why? Because they sometimes have to physically fight in order to stay alive and avoid being eaten by carnivores. Aside from teeth and claws, the meat-eating theropod dinosaurs don’t seem to have much in the way of special features that would be involved in fighting, not just eating. Ceratosaurus’ nasal horn was too thin and flimsy for attacking something, and so too were the eyebrow horns of its larger contemporary Allosaurus. However, another carnivore did possess eyebrow horns which very well might have been used in fighting – Carnotaurus, one of my personal favorites. Ever since its discovery in the 1970s, paleontologists and paleo-artists have imagined this dinosaurian toro engaged in head-butting clashes with other members of its kind. However, based upon the build of the skull, it seems more likely that it was engaged in cranial “shoving matches”, in which both competitors would press their skulls against one another (hence the Velcro-like arrangement of bumps and nodules on the top of their heads in between the horns) and proceed to push and shove in a demonstration of pure muscular strength until one side or another decided that their opponent was too strong, and retreated.

While predators might not necessarily have physically struck each other with their skulls, they could have used their heads in another way that is far more common among carnivorous animals of all sorts today – face-biting. Face-biting is a way to assert dominance among individuals, especially in communal or pack-hunting societies. Several modern carnivorous animals, such as lions, foxes, and wolves, engage in this behavior. The infamous creature known as “Jane”, who might be either a Nanotyrannus or a juvenile Tyrannosaurus (to this day, nobody is exactly sure), has evidence of face-biting. Since many animals today who engage in face biting do so in order to assert their position of dominance in a pack society, this could be further evidence that this animal was itself a pack hunter, at least as a juvenile. At least one specimen of a juvenile Daspletosaurus also has evidence of face-biting. Sue the T. rex possesses marks on the jaw which were previously thought to have been the result of bites, but were later proven to have actually been caused by a bone infection.

Predators aren’t the only animals today that engage in face-biting, so there may have been herbivorous dinosaurs that engaged in the same behavior. The most likely candidate for this is the small African herbivore Heterodontosaurus. The tusks on this creature could have been wielded in actual biting, or they could have been used for fang-bearing contests like modern baboons. Many animals bear their fangs or canines when aggressive, and Heterodontosaurus possibly did this to intimidate rivals and scare off predators. Another animal that can be compared with Heterodontosaurus is the musk deer. However, their long saber-like canine teeth are grown for display, not combat. Musk deer grow huge teeth instead of growing antlers in order to over-awe rival males and to impress females.

Another possibility for serious dinosaur fights was among the sauropods. With their massive builds, any hit, no matter how light, likely would have caused some kind of damage. One modern long-necked animal that uses its body in sheer brute force is the giraffe – a rather placid-looking animal, but don’t make it angry. During the mating season, male giraffes will proceed to whack each other, swinging their long stiffened necks around like baseball bats, with the short stumpy horns on the tops of their heads inflicting some serious pounds-per-square-inch. Some sauropods, like Apatosaurus, had very massive thick necks in proportion with their body size. This leads some to speculate that Apatosaurus and its ilk used their bruiser builds to inflict bruises on others.

Apatosaurus louisae. © Jason R. Abdale. May 11, 2020.

But what about the opposite end of a sauropod? For many of them, the tail was just as long, or longer, than the neck. Tails can be effective weapons. Crocodilians and monitor lizards engage in tail whacking as a way to ward off threats. Many sauropods had thick tails, but others, like Diplodocus, have very long thin tails, and some believe that these long whip-like tails were indeed used like whips. A sharp crack across the side would make any Allosaurus wary.

Diplodocus carnegii. © Jason R. Abdale. May 11, 2020.

Of course, there are dinosaurs that almost certainly used their tails specifically for combat: the stegosaurs and the ankylosaurs. Evidence has been found for injuries inflicted by these animals upon predators, but I’m not certain if any evidence exists for stegosaur spikes or ankylosaur clubs being used upon members of their own kind. However, I can’t imagine it NOT happening.

Well, if you don’t have any biological weaponry on your side, like fangs, horns, spikes, clubs, or whatever, then raw physical force is your go-to option. There is evidence that predator species tangled with prey. The famous fossil find of a Velociraptor and a Protoceratops perpetually locked in a mutual mortal combat proves this. But this is likely an example of an attack-gone-wrong. Did dinosaurs of the same species physically grab onto and grapple with each other? Did dinosaurs wrestle, the way that some lizard species do today? Monitor lizards are a prime example of this, when two males will attack each other by essentially doing reptilian ju jitsu. Did dinosaurs wrestle? I’m not sure, but I’m leaning towards no, especially for the larger ones. Many small dinosaurs had thin delicate bones that could be easily broken, and many of the larger dinosaurs simply did not have the arm dexterity to do rough-and-tumble wrestling maneuvers the way that you see monitor lizards doing today. Furthermore, with their large size, being body-slammed to the ground would have done a lot of damage. As they say, the bigger they are, the harder they fall. Many dinosaurs show signs of physical trauma, including broken bones. Many led a very brutal life, with some skeletons being covered with injuries. For those reasons, I would say that most dinosaurs wanted to avoid intense physical combat.

Sometimes, the violence goes to its absolute extreme, and animals deliberately kill each other. Like intra-species fighting, intra-species killing has several motivating factors, both environmental and social. Animals kill each other to either reduce or totally eliminate competition over limited resources. Animals will also kill rivals to increase their own chances for mating, as well as killing the offspring of rivals to increase their own offspring’s chances for survival. As an example, new male lions that take over an existing pride will often kill all of the pride’s cubs in order to completely eliminate the legacy of the preceding male leader.

The most extreme form of intra-species combat is killing followed by cannibalism. Although it is largely taken for granted that prehistoric carnivorous animals ate their own kind under certain circumstances, there is little evidence to support this hypothesis. Some animals will kill and eat the young of other individuals in order to improve the chances of survival for their own young. Others may kill and eat their own kind out of starvation. Still others, like alligators, may view other members of their own kind as a legitimate food source, no different than any other prey item, and actively hunt, kill, and eat each other.

For a long time, it was believed with the firmest dogmatic conviction that the late Triassic dinosaur Coelophysis practiced cannibalism. However, this long-held belief has come into question upon closer examination of the famous Ghost Ranch specimens. It now appears that many of the bones which were previously believed to be inside the ribcages of others were actually lying underneath the ribcages. Furthermore, some of the bones previously identified as juvenile specimens have recently been re-identified as belonging to other reptile species. For the record, I am not stating that Coelophysis never engaged in cannibalism. I am stating that the evidence for cannibalism in this species is not as clear-cut as once believed and needs to be taken with a certain degree of doubt. If the study of paleontology has taught me anything, it’s that there is no such thing as dogma.

Coelophysis. © Jason R. Abdale. April 26, 2015.

Although there’s questionable evidence for cannibalism in Coelophysis, there is more compelling evidence in another dinosaur from the opposite end of the Mesozoic spectrum – Majungasaurus, an abelisaurid from Madagascar who lived at the very end of the Cretaceous Period. In 2007, scientists published findings that tooth marks discovered on some Majungasaurus bones matched the teeth in Majungasaurus’ jaws. So far, this is the only conclusive proof that a theropod species killed and/or ate the flesh of its own kind. I would like to say one thing, though: just because there’s evidence that an animal was cannibalized, that doesn’t necessarily mean that this individual was killed by the animal feeding off of it. As said before, scavengers will sometimes eat the dead bodies of their own kind. To them, meat is meat, no matter where it comes from. Others will not usually eat their own kind, but will do it if they’re desperate enough and cannot find other sources of food. As an example, most humans who have engaged in cannibalism do it out of necessity, not out of habit.

In conclusion, animals will hurt each other and kill each other for a variety of reasons, not only between species but also within species. Competition for mates, competition for food and territory, and establishing your position within the social hierarchy are all seen within the modern animal kingdom, and it’s highly likely that dinosaurs did the same.

Alamosaurus

alamosaurus

I know that it’s been a while, but here is my latest addition of paleo-art to this blog. Behold – Alamosaurus, a behemoth of a sauropod that roamed Texas during the late Cretaceous Period. Alamosaurus was a member of the “titanosaur” family, which is more well-known from species found in South America, Europe, and Africa. No complete skeleton of Alamosaurus has ever been found, so we only have a rough idea about what it looked like, and we’re not even sure how big it was when it was fully grown. The most common estimate that I’ve seen is that it was somewhere around 65 – 70 feet long, but it might have been bigger than that.

Because no complete specimen of Alamosaurus has been found, you’re going to see a lot of variation in paleo-art reconstructions of this animal. From what I’ve gathered, a lot of the pictures that are visible on the internet these days are inaccurate. Alamosaurus had a massively thick neck, but its tail was not correspondingly long or massive. The presence of osteoderms along its back are a guess, since other titanosaurs, notably Saltasaurus, were known to have had them.

Dinosaur Day 2015 at the Garvies Point Museum

GP Museum 1

Well, it was that time of year again! Every April or so, at around the time of Easter, the Garvies Point Museum and Preserve, located in Glen Cove, Nassau County, New York, holds it annual “Dinosaur Day”. This is one of the days that I really look foward to for a few reasons. First, I get to work at a place that I absolutely love and meet with some good friends. Secondly, I get to be out of NYC for a little while, which is something that I ALWAYS look foward to. Third, I get to talk about a subject that has fascinated me since my earliest days – paleontology.

Veronica, the museum’s de facto head of administration, did a wonderful job along with other members of the museum staff of setting up the classroom where the day’s major activities would be taking place. Recently, the museum’s library was substantially increased. The Sands Point Museum and Preserve had closed down its library a short while ago, and all of the books and papers were sent to the GPM. I should state, though, that almost all of these documents were originally part of the GPM collections anyway, and they just got them back, that’s all. However, Louis (one of the workers at the Garvies Point Museum, but works primarily at the Old Bethpage Village – another place that I really love) has been working hard to re-catalogue all of these books and papers back into the museum’s database.

The name of the event was somewhat misleading, as it concerned all prehistoric life, not just dinosaurs. We had exhibits on primitive mammal-like-reptiles, dinosaurs, and prehistoric mammals.

Here are some pictures of what the room looked like both during and after the hoards of kids showed up.

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Most of the really young children gravitated immediately towards the dino toy area and the fossil digsite. The older children and a lot of the adults were interested in the information that I and others were giving. They were especially interested in Dimetrodon, the famous sail-backed pelycosaur from the early Permian Period. I don’t think that I have ever had to say the name”Dimetrodon” so many times within the course of a single day! It seemed to be the only thing that many of them wanted to talk about!

Some of the major topics of interest on this day were: the Permian Mass Extinction, which occured about 251 million years ago, when an estimate 95% of all life was wiped out; of course, T. rex was a favorite; as too was Allosaurus, who competed with its larger relative for attention from the crowds. This was helped in no small part to the fact that we had a lot of Allosaurus “stuff” arrayed for them: a picture of the skull, a hand model, bone casts, a model, and my drawing which you might recognize from an earlier post on this blog.

Finally, here’s a picture of me, “the Dinosaur Man” as several members of the museum staff call me, dressed up as an amateur paleontologist. In addition to my olive drab Garvies Point Museum shirt, I also wore a khaki utility vest, because apparently ALL paleontologists wear khaki utility vests! I thought that wearing it would help to enhance my ethos with the audience, and by my reckoning, it worked.

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Camarasaurus

Camarasaurus

Here’s a drawing that I did a while ago, but for some reason, my computer screwed it up. It’s only recently that I’ve re-scanned it and fixed it up.

Camarasaurus was the most common sauropod dinosaur within the Morrison Formation of western North America during the late Jurassic Period. Other species like Apatosaurus and Diplodocus might be more familiar to the ear, but in terms of the sheer numbers of specimens that have been found, this big guy tops the list. As far as size goes, it was a tad on the small side for a sauropod, measuring only 60 feet long. Its relatively small size (that is, compared with the other larger sauropods that it shared its habitat with) and meaty build likely made it one of the preferred targets for a mob of Allosaurus to take down. The reason why Camarasaurus was the most common species of its kind might be due partly to its smaller-than-average size (smaller stomachs mean more food to go around for everyone, and by extent leads to having larger populations) and partly to its apparently generalistic diet. Creatures which have a specialized diet are often hit hard when catastrophies arise, whereas dinosaurs that are more adaptable and flexible in terms of what they eat come out more favorably.

Many times, you’ll see these dinosaurs illustrated Gregory Paul-style, with thin spindly legs. I decided that the biomechanics of this simply weren’t feasible, and so I gave my animal suitably thicker more elephant-like legs, able to hold up the tens of tons of weight. Also notice that, contrary to other artistic renderings of this species, the neck is NOT held straight vertically upright, but is thrust more forwards in a 45 degree S-shaped curve. This is also one of the few dinosaur drawings that I’ve done in color. In terms of the color pattern, I’ve always imagined Camarasaurus colored in the scheme that you see above, even as a little kid – tan body with broad brown stripes and a somewhat yellowish-tan underbelly. I simply cannot imagine this species colored in any other way.

Keep your pencils sharp, people.

News: Stephen Czerkas, famous paleo-artist, dies at 63

Today, I learned some very heart-breaking news. Stephen Czerkas, one of the true greats of paleo-art, recently died. He was 63 years old. The cause of death was liver cancer.

Czerkas was famous for his life-sized dinosaur sculptures, and he developed a very distinctive style – you could immediately recognize a Czerkas sculpture. His horned Allosaurus graced many children’s dinosaur books and TV shows, and his life-sized Carnotaurus was truly epic. However, his most famous work was his pack of Deinonychus raptors. Czerkas was one of the first paleo-artists to have his theropods adorned with feathers, and he also discovered that at least some species of sauropods had spines on their backs, which was incorporated into the BBC series Walking with Dinosaurs.

To all of those dino-lovers of my generation – those who came of age during the 1990s – Stephen Czerkas’ work would have been an integral part of your life. Czerkas was one of THE paleo-artists of the late 1980s and early 1990s, the time when I was becoming exposed to dinosaurs and other prehistoric life. The sheer awesomeness of his work influenced me profoundly both as an artist and as a person who dedicated his life to studying the past.

The paleontological and artistic spheres have lost one of the true greats of their domain, but his work will last and I dare say will continue to influence artists, scientists, and children generations from now.

RIP Stephen Andrew Czerkas (1951-2015) 😦

The Presence and Usage of Osteoderms in Dinosaur Paleo-art

Many times, paleo-artists take a feature that was found in a few species and ascribe it to entire groups. One of these trends is to portray osteoderms on the bodies of dinosaurs in their artwork. The word osteoderm literally means “skin bone”. These are small pieces of bone which are embedded in the skin, and sometimes protrude out of it so that they look like bony bumps on the dinosaur’s body. Evidence suggests that they were often covered with a keratinous scute. The most prevalent example of dinosaurs possessing osteoderms is a group called the thyreophorans, meaning “shield-bearers”, which includes the stegosaurs and ankylosaurs, but other dinosaurs have them too. At least one titanosaurid sauropod, Saltasaurus, has been found with osteoderms, and it is believed that possibly all titanosaurs had osteoderms as well.

One contentious issue regarding osteoderms is their presence in theropods, or rather, in artwork depicting theropods. There is a tendency among paleo-artists to adorn the bodies of theropod dinosaurs with rows of small osteoderms along their neck, back, and tail, and I too have been guilty of this practice. However, as far as I am aware, only two theropod dinosaurs have been found with osteoderms: Ceratosaurus (western USA and possibly Africa, Late Jurassic) and Carnotaurus (Argentina, Late Cretaceous). Both of these dinosaurs were, cladistically-speaking, primitive, and were probably closer both in appearance and genetics (and almost assuredly intelligence) to early primitive archosaurs than to later theropod groups.

In terms of appearance, Ceratosaurus was found with a single row of small osteoderms running down the middle of its back (NOT multiple parallel rows, as is often shown in some works of paleo-art), extending from the back of the skull and running all the way down to the tip of the tail. Carnotaurus was found with excellent skin impressions on portions of the body, and these showed that the body was covered in non-overlapping reptilian scales, not feathers. The scales themselves were irregular in pattern and arrangement, with some being larger and more pronounced than others. Also, on the back were arranged several parallel rows of osteoderms, spaced at regular intervals. The osteoderms became larger the closer they were to the middle of the body (medially).

Ceratosaurus. © Jason R. Abdale. April 23, 2012.

 

Carnotaurus skeleton, Museu de Ciências Naturais da PUC Minas. Photograph by Roberto Murta (November 19, 2009). Public domain image. https://commons.wikimedia.org/wiki/File:Dinossauromcnpucminas.jpg.

 

In terms of cladistics, Ceratosaurus and Carnotaurus belong to the same group of theropod dinosaurs, Ceratosauria. Specifically, Ceratosaurus is a ceratosaurid and Carnotaurus is an abelisaurid, which is a slightly more advanced line. It may be possible that all theropods within Ceratosauria were adorned with osteoderms, but we cannot be 100% certain of this. However, as I said earlier, some paleo-artists have a tendency of taking a feature found in one or a few specific animals and ascribing this feature to the entire sub-group of dinosaurs. For example, a few paleontologists and paleo-artists believe that many and perhaps all sauropods had a row of keratinous spines running down the neck, back, and tail just because ONE specimen of Diplodocus was found with them. While this proves that this particular species and possibly the genus had this feature, it does not mean that all diplodocid sauropods had these keratinous spines, and it certainly doesn’t prove that all sauropods in general had this feature. The same goes for theropods. Many paleo-artists place osteoderms on their meat-eating dinosaur’s bodies simply because osteoderms have been found in association with two carnivores, and they decided to put them on virtually every theropod that they drew or sculpted.

Extrapolation is no sin. There’s nothing wrong about making an observation about something and suggesting that something else which was similar may have had identical properties. Writers and researchers do it all the time. However, I should warn people out there that there are varying degrees of extrapolation. It’s one thing to make an observation based upon the fossils of these two dinosaurs, which, as I stated before, came from the same theropod sub-division, and assume or hypothesize that other species within this particular group may have had this feature as well. It is quite another thing to take that feature and apply it to every theropod genus from Eoraptor to Velociraptor.

But what about “scutes” on dinosaurs? The term “scute” has two definitions: either it is the scale-like covering over an osteoderm, or it’s simply an unusually large thick scale. Preserved skin impressions from multiple species have shown that some dinosaurs had rows of large, thick, texturally-pronounced scutes arranged on their bodies, but these scutes did not have a bony core – therefore they can’t be classified as “osteoderms”. Examples of animals that have this feature are the stegosaur Hesperosaurus and the ceratopsian Chasmosaurus.

Chasmosaurus. © Jason R. Abdale. March 31, 2016.

 

I may sound like I’m being self-righteous and pontificating, but I too am guilty of making wild extrapolations and assumptions when it comes to my prehistoric illustrations. A few years ago, I did an anatomical study of Tyrannosaurus rex in a running pose, and I had it with osteoderms, for no other reason other than so many other paleo-artists had pictured T. rex with osteoderms in the past. I followed the crowd and illustrated my T. rex accordingly. However, later on when I read about tyrannosaur skin impressions, I learned that these large tyrannosaurs had small pebbly skin with no osteoderms. Consequently, I revised my drawing, which you can see here.

Another example of where I might have made a mistake is in my drawing “Giganotosaurus head study”, which was showcased in an earlier post on my blog; you can see it here. The reason why I had put those rows of bony bumps on its neck and a few on its jaw was because at the time I thought that Giganotosaurus was an abelisaurid, which is a sub-division of Ceratosauria. I later learned that it wasn’t, but I didn’t want to change the picture – I think it looks nice as it is. However, I’ll be sure to learn all of the information that I can about a certain subject in the future before I draw it.

What I’m trying to do here is caution paleo-artists and aspiring paleo-artists about the dangers of making wild assumptions and extrapolations. Do your homework, do your research, and illustrate your creations as best as current science allows, and don’t do anything that you aren’t able to back up with researched facts and/or persuasive arguments.

Keep your pencils sharp.

Tyrannosaurus pair attacking Alamosaurus

Tyrannosaurus pair attacking Alamosaurus

This was a drawing that I made to accompany my “Tyrannosaurus rex head” drawing. It shows a pair of T. rexes pursuing and attacking an Alamosaurus. This is something that is rarely seen in Tyrannosaurus paleo-art. Usually, the large carnivore is seen attacking a Triceratops or a hadrosaur. I’ve only seen a handful of examples where a T. rex is attacking an Alamosaurus. Alamosaurus was a titanosaurid sauropod which inhabited the southern part of North America during the Late Cretaceous. As far as I am aware, it was also the only sauropod existing in North America during this time. Contrary to what nearly everyone thinks, it is NOT named after the Alamo in Texas, but this is a side-point. I wanted to “raise the population”, so to speak, of illustrations depicting a clash between these two large North American dinosaurs. I hope you enjoy it.