Sinosaurus: Beast of the Week

This week we will be looking at one of the first large predatory dinosaurs.  Make way for Sinosaurus triassicus!

Sinosaurus triassicus life reconstruction in watercolors by Christopher DiPiazza

Sinosaurus was a meat-eating dinosaur that lived in what is now Southwest China during the early Jurassic period, between 201 and 196 million years ago.  From snout to tail it measured 18 feet (5.5 meters) long. It's genus name translates to "Chinese Lizard/Reptile" and the species name is in reference to the Triassic period which is when it was first believed to have lived upon its discovery. (We now know it was in the Jurassic.)

Sinosaurus is a dinosaur that underwent a few identity changes as paleontologists discovered more fossils and learned more about it over the years.  Most prominently it was believed to be an Asian species of the more popular North American theropod, Dilophosaurus, and was originally named Dilophosaurus sinensis.  This makes sense at first since both of these dinosaurs are known for having two bony crests on the top of their snouts.  They both also even have a similar notch towards the front of their upper jaws.  However, as more material from Sinosaurus was unearthed over the years, it was determined that it was more closely related to later kinds of theropods, called the tetanurans, and therefore was given its own genus name, Sinosaurus.  Tetanurans are a broad group of theropods characterized by how their tails were stiffened in life thanks to how their tail vertebrae interlock together.  Tetanurans are also all more closely related to birds than to other dinosaurs, including other kinds of theropods.  According to this updated idea, Sinosaurus was particularly closely related to another crested theropod from the early Jurassic, Cryolophosaurus.  

Sinosaurus skeletal mount on display at the Maryland Science Center in Baltimore, Maryland, USA.

Sinosaurus had curved serrated teeth that would have been ideal for slicing through and stripping off chunks of meat from bodies.  The upper jaw notch towards the front of its snout may have been an adaptation for hooking into and ripping through the skin of other dinosaurs to get into the meat inside, similar to the hooked beaks of modern carnivorous birds, like hawks, eagles, and vultures.  Sinosaurus is probably most known for its bony crests which adorned the top of its skull.  These crests had holes in them, making them lightweight, and may have served as visual display adaptations within the species or even possibly could have helped absorb impact, allowing Sinosaurus to bite harder without injury.

Sinosaurus skull from in Zhang's 2023 paper. (listed below)

Sinosaurus shows evidence of tooth injury in life in the form of what is called alveolar remodeling.  This means that it experienced a broken tooth and the ridge of bone in the jaw that includes the tooth sockets, called the alveolar bone, changed shape in the healing process following the loss of the tooth.  Dinosaurs losing and replacing teeth is common in the fossil record, but this is the only recorded instance of an actual tooth related injury that healed in this way known so far for a dinosaur.  

Sinosaurus lived during a time when predatory dinosaurs were first starting to get truly large.  Prior to this most meat-eating dinosaurs were much smaller and more gracile, like Coelophysis, and even the biggest plant-eaters, like Plateosaurus, weren't that huge compared to what would later evolve.  At 18 feet long, Sinosaurus was likely the top of the food chain in its environments.  

References

Chung-Chien, Young (1940). "Preliminary Notes on the Lufeng Vertebrate Fossils*: Young:-Lufeng Vertebrate Fossils". Bulletin of the Geological Society of China. 20 (3–4): 235–240.

Dong, Z.M. (2003). "Contribution of New Dinosaur Materials from China to Dinosaurology" (PDF). Memoir of the Fukui Prefectural Dinosaur Museum. 2: 123–131.Xing, L.D.; Bell, P.R.; Rothschild, B.M.; Ran, H.; Zhang, J.P.; Dong, Z.M.; 

Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology. 69: 215.

Zhang, W.; Currie, P.J. (2013). "Tooth loss and alveolar remodeling in Sinosaurus triassicus (Dinosauria: Theropoda) from the Lower Jurassic strata of the Lufeng Basin, China". Chinese Science Bulletin. 58 (16): 1931–1935.

Zhang, Z.-C.; Wang, T.; You, H.-L. (2023). "A New Specimen of Sinosaurus triassicus (Dinosauria: Theropoda) from the Early Jurassic of Lufeng, Yunnan, China". Historical Biology. in press.

The Paleontology Behind Pokemon: Part 3

 It is time for my third installment of Paleontology Behind Pokemon, a post where I delve into the design choices behind pokemon based on dinosaur and other prehistoric animals.  If you have not seen the first two pokemon posts you can check out part one here and pat two here.

Walking Wake

The newest generation of pokemon yielded a few exciting new desings that are clearly based on pokemon.  Possibly the most surprising is the new look of the legendary pokemon, Suicune, called Walking Wake.  Suicune was originally based on a dog or a generalized mammal, but Walking Wake is very clearly based on a theropod dinosaur.  It has a proportionally smaller head, long legs, and short arms with three fingers on each hand.  At first it looks like it could be a dromaeosaur but it doesn't have the signature giant toe claw on each foot and I feel that if a pokemon were to be based on a dromaeosaur that would be the one feature that would be included, if not emphasized.  

Dryptosaurus skeletal mounts on display at the New Jersey State museum.

My realistic assumption is Walking Wake isn't based on any particular taxa or even group of dinosaur beyond theropod, but in my headcannon it is a tyrannosauroid, like Dilong, Moros, or Dryptosaurus.  I named mine "Drypto" for that reason. (plus it's water type and drypto sounds like drip which is a thing water does.)

Frigibax, Arctibax, and Baxcalibur

Walking Wake wasn't the only dinosaur introduced in the newest wave of pokemon.  We also have the evolution line of dragon/ice pokemon, Frigibax, Arctibax, and Baxcalibur.  All three of these pokemon also appear to be based on theropod dinosaurs and all three sport a blade-like fin or ridge on their backs.  At first Spinosaurus seems the most likely source of inspiration, but they lack the long snout of a spinosaur and pokemon is usually pretty good about using up to date looks when they do use specific dinosaurs for references.  I have also read they are based on Concavenator, which also has a more isolated fin-shaped hump on its back.  Part of me can't help but wonder if their names are playing off of dinosaurs, like Altispinax and Becklespinax, both of which also had high ridges on their backs, but are known from much less complete fossil material.  

Concavenator skeleton on display at the Fukui Prefectural Dinosaur Museum.

As always it is also always safe to assume these pokemon could be inspired by all or many of the above fossils, resulting in a more generic, but no less cool, design.  I also want to note that Arctibax looks the most like an actual dinosaur, due to its posture, and the fully evolved Baxcalibur looks more like Godzilla than a real dinosaur due to its proportions and more upright posture.

Tropius

Tropius is a pokemon introduced in the third wave of pokemon games.  It is a grass/flying type and is clearly based on a long-necked sauropod dinosaur.  I have also read it is more specifically inspired by the cryptid, Mokele-mbembe, a sauropod dinosaur said to live in the Congo River according to legend.  The grass typing and incorporating banana trees into the design is pretty clever, but the flying typing is just bizarre in my opinion.  A sauropod seems like the least likely animal that would be flying, especially with wings made of leaves!  I also always found it odd how Tropius has no tail.  

Chikorita, Bayleef, and Meganium

Speaking of grass type sauropods, we can't forget Chikorita and its evolutions.  Introduced in the second generation of pokemon as one of the starters, Chikorita's design isn't obvious at first.  But once it evolves, gaining a long neck, it becomes pretty clear this little pokemon is a sauropod. 

Giraffatitan skeleton on display in Berlin.

The final evolution, Meganium is even more obvious.  I can't help but think of them as brachiosaurs, since Meganium has a shorter tail and more upright neck posture.

Great Tusk

Another new pokemon introduced in the latest generation is the ancient form of the second generation pokemon, Donphan, called Great Tusk.  Donphan was based on elephants and Great Tusk appears to be mostly based on Mastodon or Mammoths, based on its tusk shape.   

Mastodon skeleton on display at the Rutgers Geology Museum.

It also looks like actual dinosaur features were incorporated into it as well with its armored back, spikes, and reptile-like tail. 

Breloom

Breloom is a grass/fighting type pokemon that evolves from Shroomish, a literal mushroom.  But Breloom appears to take the mushroom theme and apply it to a dinosaur shape, standing on two digitigrade feet, having short arms, a beak, and a long tail.  

Stegoceras skull.  Breloom's head resembles the flared out and domed skulls of many pachycephalosaurs.

Specifically Breloom looks to be most similar to pachycephalosaurs, with the wide mushroom cap on its head resembling a domed skull.  

Tyranitar

Tyranitar is a pokemon released in the second generation of pokemon.  It is a rock/dark type and has always been one of the most popular pokemon based on its cool design and strength in battle.  Tyranitar is also the first pokemon I've written about here that isn't actually based on anything from paleontology directly but I kept getting requests on social media to include it since I started writing these posts so I figured I'd finally set the record straight here.  At first Tyranitar seems like it would be based on a Tyrannosaurus, but I'm convinced this is based on its name only and little else.  In fact, nothing about its actual design is directly based on any real dinosaurs beyond anything extremely general.  Tyranitar DOES however appear to be directly based on a kaiju (Japanese giant monster traditionally represented by an actor in a costume) from the Ultra Man franchise, named Bemular.  

Bemular, the monster Tyranitar appears to be the most based on.

Habrosaurus: Beast of the Week

 This week we'll be checking out a prehistoric amphibian.  Make way for Habrosaurus!

Habrosaurus was a salamander that lived in what is now Alberta, Wyoming and Montana, during the late Cretaceous period into the early Paleocene (surviving the asteroid that wiped out most of the dinosaurs), from 68 to 58 million years ago.  From snout to tail Habrosaurus is estimated to have been over five feet (1.6 meters) long, making it one of the largest salamanders of all time.  When alive Habrosaurus likely would have likely preyed on smaller aquatic animals, like shrimp and mollusks. (all amphibians are predators at least as adults) The genus name translates to "Graceful Reptile" even though it was and amphibian, not a reptile.

Life reconstructions in watercolors of Habrosaurus dilatus by Christopher DiPiazza.

There are currently two species of Habrosaurus known on the fossil record.  Habrosaurus prodilatus is the older species, lived in what is now Alberta, Canada, and would have shared its habitat with dinosaurs like Styracosaurus, Parasaurolophus, and Gorgosaurus.  Habrosaurus dilatus is the later species and lived in what is now Western United States, and would have shared its home with dinosaurs, like Triceratops, Ankylosaurus, Pachycephalosaurus, and Tyrannosaurus.

Habrosaurus was a member of the siren (sirenidae) family of salamanders which have numerous species still alive today, all native to the southern United States.  Sirens are characterized by having extremely long, eel-like bodies, front limbs only (no back legs), gills, and live their entire lives in freshwater but can also burrow into the mud if they need to.  Unlike many amphibians, sirens do not undergo metamorphosis, but rather stay fully aquatic their entire lives, simply growing larger as they age.  

Teeth and jaw fragments from Habrosaurus dilatus from Gardner's 2003

 paper linked below.

Fossils of Habrosaurus dilatus' teeth indicate that it specialized in eating hard-shelled prey, like snails and shrimp.  Both species also may have been preying on fish and other animals small enough to fit in their mouths if they wandered too close.  Living sirens are some of the few kinds of amphibians known to actually be omnivores as adults, supplementing their mostly meat diet with water plants, as well.  There is no way to know if Habrosaurus may have eaten some plants as well when it was alive.  iLike living sirens, Habrosaurus likely spent its time on the muddy bottom of swamps and other bodies of fresh water, where it relied on secrecy to ambush prey.  I wonder how many unsuspecting large dinosaurs were bitten on the nose by an angry Habrosaurus, as they tried to take a drink?

That's all for this week!  Leave a comment below!

References

Gardner, James D. (November 2003). "Revision of Habrosaurus Gilmore (Caudata; Sirenidae) and relationships among sirenid salamanders". Palaeontology. 46 (6): 1089–1122.

Hill, R. L., Mendelson, J. R. & Stabile, J. L. 2015. Direct observation and review of herbivory in Sirenidae (Amphibia: Caudata). Southeastern Naturalist 14, N5-N9.

K. Roelants, D.J. Gower, M. Wilkinson, S.P. Loader, S.D. Biju, K. Guillaume, L. Moriau, F. Bossuyt (2007) Global pattern of diversification in the history of modern amphibians. Proc. Natl. Acad. Sci. USA, 104: 887-892