STL Science Center

STL Science Center

27 February 2018

Titanophoneus Written in Ink

Possessing teeth and bodies that were grotesque and enormous, by Permian standards at least, Titanophoneus has been the center of a few hypotheses (alongside Gorgonops) of how dinocephalians hunted and killed their prey. Existing before Gorgonops (Late Permian), Titanophoneus may have laid some of the behavioral groundwork, in the Middle Permian, for the slightly better known predator of the Late Permian. Barghusen (1975) discussed these hypothetical behaviors and inferred their implications for inter- and intra-species combat in dinocephalians. Some of the adaptations discussed by Barghusen were also discussed by Rowe and van den Heever in 1986 and Hopson in 1995. These two papers both discussed the evolution and characters of the manus ("hand" in some mentions in the two papers) of dinocephalians. The original descriptions of Titanophoneus are largely missing, online. Therefore, the best descriptions that we have online are in these three articles and the Tree of Life website. Lauren and Reisz edited the "Autapomorphies of the main clades of synapsids" page which covers any and all characteristics that may gave been previously overlooked or ignored in the papers on feeding/fighting and the hand.

26 February 2018

The Ancient Earth

I would like to start off today by admitting that I am an absolute sucker for documentaries about animals, not specifically fossil animals either, but animals in general. That is why, despite a large number of videos of animatronic Titanophoneus models and numerous "tribute" videos on YouTube, I want to share a somewhat lower budget documentary about the Permian today. As we should remember, Titanophoneus was a massive predator of the Permian and used its size as well as relatively large canine teeth to subdue ts prey. The producers of the show Ancient Earth, CuriousityStream, run an on demand online streaming site that shows scientific, historical, and technology content (think of it as Discovery back in the mid-90's). A free trial is available for the service and it is the only way I have found, so far, to watch the documentary Ancient Earth. This show has an episode on the Permian which features Titanophoneus and discusses the Permian mass extinction. The two clips linked here show trailers of the show that mention and show Titanophoneus as it appears in the documentary.

24 February 2018

Gigantic Murderer

The Permian landscape was filled with enormous therapsids. As we have discussed in past entries (see Moschops), the therapsids are the group of synapsids that includes mammals and their descendants. During the Permian the group of therapsids known as dinocephalians were a small, but mildly successful group for about 10 million years (270 - 260 million years ago). Some of these animals were absolutely terrifying in appearance, possibly because they look like nothing currently living on the planet. One of the more alien looking, and named, dinocephalians of the Middle Permian was the 5 m (16.4 ft) long Titanophoneus potens Efremov, 1938. The name Titanophoneus translates to "Titanic murderer" and the large carnivore prowled the Middle Permian with an 80 cm (2.62 ft) long skull and teeth to match (in that they are huge, not 80 cm long).
©Dmitry Bogdanov
Titanophoneus & Ulemosaurus

23 February 2018

A Turtley Picture

A lot of images online are non-descript turtles; sometimes freshwater turtles manage to sneak into the search results for Desmatochelys. A number of unidentified, both artist and subject, turtles also appear, making finding an accurate interpretation as well as attributing that interpretation almost impossible in some ways. Regardless, a lot of turtle illustrations are really great, for a number of different reasons. The underwater lighting in most of these images that I have looked at today is wonderfully done, which further enhances the natural majesty of these giant marine turtles. Desmatochelys in action looks, no matter the artist, like many other sea turtles as they swim through the scene in which they are depicted. This version of Desmatochelys is fairly majestic, but has a few non-majestic characteristics as well (I think it might be the angle of the head).

21 February 2018

Turtle Bits Everywhere

The 2007 Colombian skeletons that were described by Cadena and Parham 2015 consisted of at least four individuals; four skulls that are either entirely or nearly entirely complete were among these remains. The holotype from this set of remains of Desmatochelys padillai consists of one of the incomplete skulls as well as portions of the neck (hyoid and vertebrae 3-8), both forelimbs with incomplete digits, the left shoulder girdle, and most of the upper (carapace) and lower (a partial hyoplastron and hypoplastron) shell. Two additional partial shells were also recovered in 2007. The remains constitute the oldest known marine turtle at approximately 120 million years old; the next oldest fossil marine turtle is an animal known as Santanachelys gaffneyi at 95 million years old.

These turtles were not tiny marine animals either. The Colombian fossils had heads that, at their largest, measured 320 mm (12 in) long and 216 mm (8.5 in ) wide (specimen FCG–CBP 01). The known material of the carapace of this specimen measured approximately 1660 mm (2.17 ft) long and 1353 mm (4.44 ft) wide. As we can see below, this was a rather large and impressive turtle.
©Edwin Cadena

20 February 2018

The Turtle Papers

The history of Desmatochelys is a very well-documented one, with many of the fossils described and analyzed a variety of ways. Some of these descriptions of course include Williston 1894 and Cadena and Parham, 2015. The Cadena and Parham article is fairly long and highly detailed and, thankfully for us, hosted online by the University of California system; the article appeared in PaleoBios which is published by the University of California Museum of Paleontology. A lot of this article discusses the phylogenetics of marine turtles and these sections are accompanied by enormous colorful figures and phylogenetic trees. Much of the discussion contained therein is the result of studies that came before Cadena and Parham, allowing these authors to make the inferences that they detail in their article. Many of those arguments and discussions were originally written by Elizabeth Nicholls in the early 1990's. Nicholls, 1992 detailed an incomplete specimen of D. lowi discovered on Vancouver Island on the Pacific coast of Canada. That specimen marked the first discovery of a marine vertebrate from the Cretaceous along the Pacific coast. In her discussion of turtle specimens Nicholls argued that more specimens of marine turtles discovered in Cretaceous rocks belonged to the genus Desmatochelys and her work on the turtles is inherent in the efforts and descriptions of later marine turtles and Desmatochelys specimens specifically.

18 February 2018

Turtle Facts

Desmatochelys is a somewhat popular turtle. Being the oldest known fossil sea turtle most likely only enhances the popularity of the fossil. However, the fossil has few fact pages and videos online. One of the only human-voiced videos on YouTube is the GeoBeats News video shown below. Enjoy the video today and tomorrow we will look at some of the other videos. Later in the week we will discuss some of the facts that we know about Desmatochelys, where they came from, and how we know what we know.

17 February 2018

The Oldest Sea Turtle

©Jorge Blanco
Desmatochelys is the oldest sea turtle known to science. Consisting of two species, D. lowi Williston 1894 and D. padillai Cadena and Parham, 2015, Desmatochelys is known mostly from Colombian fossils of D. padillai recovered in 2007. However, D. lowi is known from a very well preserved specimen from Nebraska described by Williston in 1894 and potential remains recovered from Kansas in 2008. The reason that the 2007 discoveries and their 2015 description are more well-known is because they are more current, very well preserved, and the description includes an extensive list of characters and depth. All of the known specimens of this turtle genus are amazing, so it really is difficult to say any one is better than the other specimens and each has its merits. As an example, the 2008 Kansas specimen of D. lowii has a very well preserved skull and the humerus is slightly different from Williston's Nebraska specimen of 1894. Variance, preservation, and preparation could account for this, however we may never know exactly why they appear different.

Regardless of their preservational states, the specimens of D. padillai from Colombia was recovered from rocks that are Lower Cretaceous or upper Barremian-lower Aptian, approximately 120 million years old, in age. These fossils make Desmatochelys the oldest known fossil sea turtle by approximately 25 million years. All of the fossils, from all three locations, make Desmatochelys one of the most well represented fossil sea turtles as well. As the week goes on we will list out the specimens and describe this turtle. Today, enjoy this Cretaceous landscape and its giant sea turtle.

16 February 2018

Giant Skeletons

One of the best skeletal reconstructions I have ever seen is that of Futalognkosaurus as illustrated by Nima Sassani. The image is enormous and I am going to link it here rather than describe the image in great detail. Enjoy this enormous dinosaur and its enormous skeleton.

15 February 2018

Quietly Documented

The turnaround time from fossil recovery to description for Futalognkosaurus is actually fairly standard. Discovered and recovered in 200 and described in 2007, Futalognkosaurus was only unknown to the world for approximately 7 years (with the 87 million year fossilization and exposure period). In the grand scheme of fossils that is actually not that bad a return from fossil to publication; considering it includes transportation of a number of very large skeletal elements and preparation, study, and characterization as well it is actually somewhat impressive. Since that publication Futalognkosaurus has somewhat been lost in the general awe of titanosaurs instead of standing out on its own very much.

As one of the most complete large dinosaurs ever discovered, it is famous for that distinction if for nothing else. That is a point that has been highlighted numerous times on popular media like the Smithsonian's online magazine and Sauropod Vertebra Picture of the Week (SVPOW), a popular venue for discussing sauropods. Dinosaur books describing the landscapes of South America that were written after the description was published make mention of the giant and even detail what inferences have been made about the animal, though there are not any singularly dedicated books, for children or otherwise, available on the market at the moment. An application launched in 2013 has probably been the most active way of viewing and interacting with Futalognkosaurus for the public. In conjunction with the Royal Ontario Museum, the app Scopify created a vignette for the display piece of Futalognkosaurus in the museum, bringing the sauropod to life on handheld devices and cellphones.

For the most part Futalognkosaurus does not make a giant impact on popular culture in visible media. However, despite a lack of popular media and materials, Futalognkosaurus has appeared in murals, many illustrations, and features prominently in the Royal Ontario Museum. The name is not well known, but many may recognize the sauropod as a titanosaur in illustrations and murals.

13 February 2018

Anatomy of a Titan

When Calvo, et al. (2007) described the titanosaur Futalognkosaurus they knew that their animal was one of the most immense animals that ever lived and that it was big for a sauropod, which we can all admit is saying something. Imagine someone describing a whale as "enormous, for a whale" and you might have a good idea of the scale of intensity of describing a sauropod that was larger than others of its kind. The description that Calvo, et al. released included some nice photographs, location details, and skeletal maps of Futalognkosaurus. It is not like we do not expect this kind of thing from a description paper, it is just always fairly delightful when this kind of thing is done well and in vibrant colors, as this paper is.

12 February 2018

One Worthy Video

Perhaps because Futalognkosaurus is difficult to say, the titanosaurid sauropod has not appeared in any official film media. There are plenty of amateur images of displays from museums and other things (like illustrations that were scanned). The video from WizScience shown here makes use of both illustrations and display photos. It is also one of the only videos online that talks about Futalognkosaurus in any length.

10 February 2018

Same Hemisphere, Different Continent

©Nobu Tamura
The western hemisphere is not the only side of Earth where we find giants, but we do find a lot of them. Many of these giants come from the tropical Cretaceous of Patagonia, an era and land rich with titanosauriform sauropods. Some of these have very straightforward names (e. g. Argentinosaurus, Titanosaurus) but some have names that are nearly impossible to spell correctly on the first try, such as Futalognkosaurus dukei. Futalognkosaurus is known from a large portion of the skeleton, which is a large skeleton. The neck is composed of 14 tall, deep vertebrae leading to an estimation that the neck itself with soft tissue may have been as wide as 1 m (3.3 ft). The pubis is a 1.37 m (4.5 ft) long bone, meaning that the pelvis is amazingly enormous in this dinosaur. These bones are not the only known fossils of Futalognkosaurus. The entire known skeleton, attributed to three specimens and accounting for 70% of the total skeleton, allows for a well inferred estimation of total length. Estimations run between 26 - 30 m (85.3 - 98.4 ft) of total length for the sauropod. The name reflects the enormous estimations and is, as many dinosaur names are, derived from language of the local indigenous peoples. Mapudungun, the native language of the Mapuche people of Chile was used to name the dinosaur by Calvo, et al. in 2007 and translates to "Giant chief lizard" (pronunciation of this name is given as "foo-ta-logn-koh-sohr-us").

09 February 2018

Adult or Juvenile Size?

Instead of a wonderful work of art this week, we will end this week with a size comparison of Siats and Siats. The fossil remains of Siats that have been discovered and analyzed indicate an animal approximately the size of the darker shaded version of Siats in the image here. The estimated size of Siats, as we can see here, is around 9 m long and 2.5 m tall at the hips. If this theropod was indeed a juvenile, the estimated full grown size of Siats would have been slightly larger than a Tyrannosaurus at 12 m long and 3.5 m tall at the hips. The largest known Tyrannosaurus, Sue at the Field Museum, is 12.3 m long and 3.66 m tall at the hips. The largest estimation for Tyrannosaurus is approximately 13 m long, only slightly larger than Sue or the estimation of an adult Siats.

08 February 2018

What You're Made Of

Reading the description paper or watching the interview with Pete Makovicky allowed one to look at what fossil remains Siats is composed of. In terms of fossil discoveries, from Utah, Montana, China, or anywhere else, Siats is a pretty average fossil. Unfortunately, as someone that studies the skull, there is only post-cranial material for Siats so we do not know much about how its head looked or functioned. Another thing we do not have direct evidence for at this time is feathering on this dinosaur. Inferences can be made regarding the feathering of Siats based on familial evidence, but it is important to note that the illustrations that show feathering are using phylogenetic inferences and not evidence directly from the fossils; in case anyone asks if there are feathers on this fossil when you are discussing dinosaurs one day it is important to have the correct answer.

Despite not knowing much about the skull of Siats there is enough information in the fossils for researchers like Zanno and Makovicky to know that Siats is a theropod dinosaur. These include the shapes of the pelvis and the known vertebral elements, as one would suspect. Seeing those bones on a table and hearing what they are does not necessarily tell anyone where they are in the body or where they were positioned exactly. For that reason we have skeletal illustrations that we can refer to, such as this one. Additionally, there are elements of the legs and feet, specifically portions of the tibia and individual phalanges belonging to both feet. These are not enough to flesh out the entire feet and tell us exactly what the feet looked like either, but remember, a lot of what Siats looked like comes from its known familial relationships. These relationships are well enough known that the scientific illustrations that have been created using the inferences and knowledge of these dinosaurs are well received and considered accurate.
From Zanno and Makovicky 2013

06 February 2018

Dino Paper

Zanno and Makovicky's 2013 Nature paper Neovenatorid theropods are apex predators in the Late Cretaceous of North America is pretty much the only paper that has been published on Siats meekerorum. There are a few other mentions of Siats specifically or descriptions of its family (Neovenatoridae) that sometimes very remotely mention Siats in passing. The majority of these mentions come from papers discussing the anatomy and phylogeny, or a combination of both subjects, of animals like Megaraptor and the early tyrannosaurids. These include Porfiri, et al. 2014, which describes a juvenile specimen of Megaraptor and what its anatomy can tell us about tyrannosaurid evolution and Coria and Currie 2016, which again describes a Megaraptorid dinosaur and discusses tyrannosaurid phylogeny. The reason that Siats is mention so often in tyrannosaurid evolution is that Siats is in an interesting position, phylogenetically.

Regardless of which of these papers you are reading, Neovenatorids are contained within the Allosauroidea. Megaraptorids are in a controversial position, with Siats resting either right outside the Megaraptora or as a stem member, depending on which papers one is reading. The cladograms presented on Wikipedia for Siats and Megaraptora, developed using different papers, disagree on this point. However, this shows the history of the phylogenetic positioning of Siats, not current disagreement on its position. These clades are often discussed within discussions about tyrannosaurid evolution because Coelurosaurs, the group to which tyrannosaurs belong, are the sister clade of Allosauroids, the group in which Siats is found. Phylogenetics can be intense to read about, but bearing in mind that the papers linked here discuss Siats and Megaraptorids because they are distant cousins of the tyrannosaurs that the phylogenetic discussions mention, may help sort out the importance of these familial bonds.

05 February 2018

Described by the Author

In this video Peter Makovicky introduces the world to Siats meekerorum. There are no other professional videos of Siats. There are a number of amateur dinosaur enthusiast videos online, but this 8 minute video has a lot of information on the fossil and is an interview with one of the main authors. Enjoy the interview and a look at the fossil!

03 February 2018

Neovenator Family Expansion

©Julio Lacerda, commisioned by
the North Carolina Museum of Natural Sciences
In 2013 Lindsay Zanno and Peter Mackovicky described and named a fossil from Utah of a theropod dinosaur that lived during the Late Cretaceous around 98.5 million years ago, making it slightly older than Tyrannosaurus rex. This large predator, Siats meekerorum, filled the role between its gracile cousin Allosaurus and the heavyweight Tyrannosaurus on the North American landscape. The animal is important for a number of different reasons, including, and maybe foremost, showing that allosauroid theropod predators remained dominant from the Jurassic when Allosaurus began to out compete dinosaurs like Ceratosaurus nasicornis until the very Late Cretaceous when dinosaurs like Tyrannosaurus began to out compete Siats and other predatory dinosaurs contemporaneously living in North America. Siats also fills the role of apex predator in the region during its fossil record, not that there was any shortage of predators from Utah during this time; dromaeosaurs like Achillobator and Deinonychus were also stalking prey around this time. One of the problems with this animal, as we will see during the week, is that the fossil possesses characteristics that reveal that it may be an immature specimen, and naming new species from juvenile skeletons is not ideal, though it is not unprecedented and, in a number of cases, not unwarranted either. Regardless, this week we will go over what remains were found, what they look like, and what we know about Siats meekerorum, a predator from Utah named after a Ute myth about a human-eating monster.

02 February 2018

Pick a Favorite

Picking a favorite Placodus illustration is actually quite difficult. I assumed that it would be simpler given that Placodus is a relatively simplistic looking marine reptile. However, despite its rather boring looking body plan, it has clearly inspired some rather interesting illustrations. Instead of going on about my favorites and why they are my favorites, here is the size comparison illustration and a nice study of Placodus by Dmitry Bogdanov. The size comparison shows how small Placodus actually was compared to the average human. Bogdanov's illustration shows Placodus from the side and in great detail.

01 February 2018

Popular Teeth

Placodus is a very well known marine reptile to a majority of paleontologists and the public at large. As stated on Monday, even with this popular knowledge out there floating around Placodus remains largely absent from popular culture. This is far from the first time that a widely known fossil animal has made little or not impact in popular culture. However, this armored "Triassic sea cow" has managed to exist in somewhat common knowledge despite the lack of references. Instead of harping on the lack of references, though, let us quickly look at some of the items that have managed to exist and further knowledge about Placodus. One such item is a cast that could be bought, and may have shown up in fossil theme parks. The cast is a little different from most interpretations of Placodus, but does still bear a good resemblance to the animal, particularly the front teeth, and is reasonably priced, for a large statue of a Triassic reptile. Scientific models like those made by Jacek Major and Jarosław Kołodziejski are of slightly higher accuracy, but are not mentioned specifically as being for sale. If statues and scientific models are a little big or expensive, there are toys, though I have found out that these are discontinued toys made by a company called Playvision. Placodus is shown second from the left in the bottom row: