The Triassic reptile weirdness thread

marco_polo

Interesting article suggesting that more efficent lungs gave the ancestors of dinosaurs (archosaurs) the edge over mammilian ancestors (synapsids) in the low oxygen Triassic world.

http://news.nationalgeographic.com/news/2010/01/100114-alligators-dinosaurs-birds-lungs-breathing/

Dinosaurs' superior lungs may have allowed them to outcompete early mammals, according to a new study of modern-day alligators.

Scientists found that a method of high-efficiency breathing used by birds is also employed by today's alligators, which share a common ancestor with dinosaurs.

In mammals, each fresh breath carries oxygen-rich air to "cul-de-sacs" in the lungs called alveoli.

Air circulating through these sacs transfers oxygen into the bloodstream that picks up the blood's carbon dioxide waste.

But birds don't have alveoli. Instead, the air flows in one direction into the birds' air sacs.

This adaptation keeps birds' lungs filled with "fresh" air, allowing them to breathe at altitudes that would kill other animals.

If I may speculate, add in the subsequent invention of warm bloodedness to the dinosaur lineage sometime after the split with the crocodilians and you have a recipe for world domination.

Wibbs

I thought oxygen levels were higher then than now, or was that only later in the cretaceous?

marco_polo

Wibbs wrote: »

I thought oxygen levels were higher then than now, or was that only later in the cretaceous?

I was not aware before reading that that oxygen levels were quite low in the Triassic, however it seem to make sense that this would be the case after the Permian mass extinction. They peaked up at about 30%(?) during the Cretaceous I think , once the great angiosperm radiation occured and they took over practically the entire world.

This thread reminds me that I have been meanng to buy this book: http://www.nap.edu/openbook.php?record_id=11630&page=1

Capt'n Midnight

wasn't there something abut crocs hearts being leaky being advantageous to speed up digestion.

aren't the major blood vessels of the heart in mammals and birds the opposite way or something ? - did they evolve more than once ?

remember they found the heart in a dinosaur , did they ever figure anything more about it


am reminded of that blood vessel in giraffes that goes up to the head and back down again to travel a few inches , because it looped past something else earlier in evolution - it was on the channel 4 dissection of giants series

marco_polo

Capt'n Midnight wrote: »

wasn't there something abut crocs hearts being leaky being advantageous to speed up digestion.

aren't the major blood vessels of the heart in mammals and birds the opposite way or something ? - did they evolve more than once ?

remember they found the heart in a dinosaur , did they ever figure anything more about it


am reminded of that blood vessel in giraffes that goes up to the head and back down again to travel a few inches , because it looped past something else earlier in evolution - it was on the channel 4 dissection of giants series

Willo the Thescelosaurus even has his own web page.

http://www.dinoheart.org/

There is some dispute as to whether or not it was was an actual dinosaur heart or not. See the section near the end of the page for the controversy details. http://en.wikipedia.org/wiki/Thescelosaurus

The evidence suggest that the four chambered heart evolved seperately in the archosaurs (Dinosaurs, Crocs, Birds) and in Mammals. As all other reptiles apart from the archosaurs have a three chambered heart and the mammalian and reptilian lineages diverged prior to the last common ancestor of the Sauropsida (All reptilian decendants including archosaurs)

Never heard that about about the Croc heart before it is a facinating change of direction. Typical evolution really, to go to to all the trouble of seperating the pulmonary circulatory system from the systemic circulatory system and then undoing all its good work.

http://en.wikipedia.org/wiki/Foramen_of_Panizza

According to the croc wiki page this serves to allow the mixture of oxygenated and deoxygenated blood in the left aorta. Because the left aortic archery goes directly to the gut, the shunting of oxygen depleted blood which is high in CO2 may serve to aid in creating stomach acid to assist in digesting bones from its prey.

Things learnt today + 1

marco_polo

Wibbs wrote: »

I thought oxygen levels were higher then than now, or was that only later in the cretaceous?

Found this nifty little graph of oxygen levels over the last 600 MY. It suggests that levels dropped as low as 15% in the early Triassic (And interestingly again around the Triassic/Jurassic boundary by the looks of it, which was one of the less well famous major extinction events).



Lifted from this paper:
http://www.pnas.org/content/96/20/10955.full

Adam Khor

http://phys.org/news/2012-09-archosaur-marine-triassic-southwestern-china.html

Galvasean

Pseudosuchian... I've never heard taht term before and now I love it!

Adam Khor

At least most of the time.

http://phenomena.nationalgeographic.com/2013/02/21/poposaurus-postosuchus-and-the-dinosaur-mimic-croc-walk/



You know what's funny? With theropods looking more and more bird-like with every new discovery, it is rauisuchians like these that seem to become the closest thing to our classic view of carnivorous dinosaurs...

Galvasean

It's almost like they're evolving.... in retrospect!

Adam Khor

Was an early ornitischian, about the size of a fox and apparently omnivorous:

http://latino.foxnews.com/latino/lifestyle/2014/08/07/puzzling-fox-sized-dinosaur-remains-found-in-venezuela/

Adam Khor

http://www.eartharchives.org/articles/hammerhead-marine-reptiles-vacuumed-up-algae/

Adam Khor

Triassic reptile had pachycephalosaur-like skull

http://www.sci-news.com/paleontology/triopticus-primus-triassic-reptile-04219.html

Adam Khor

http://www.eartharchives.org/articles/vivaron-haydeni-the-triassic-ghost-ranch-predator/



It is said to be the same size as Postosuchus, and it lived at the same time and in the same place. I would really like to know why this couldn t be just another Posto...

Adam Khor

Looks a lot like Sharovipteryx 
http://www.eartharchives.org/articles/unusual-reptile-glided-over-poland-230-million-years-ago/

Capt'n Midnight

another weird gliding reptile from the Triassic




+1 for Sharovipteryx

Adam Khor

http://www.media.uzh.ch/en/Press-Releases/2017/Ancient-Swiss-Reptile-.html

Rubecula

Missed this sorry

Adam Khor

https://paleonerdish.wordpress.com/2017/08/22/introducing-shringasaurus-indicus/

Fathom

Solid horn? Or hollow horn? Like subsurface snorkel? Mobile proboscis used as abreathing tube? Like a specific variation of hadrosaurs?

Adam Khor

It looks pretty similar to ceratopsian horns, which unless I'm mistaken were pretty solid. Because they point forwards it would follow that they were used to fight- both potential predators and, especially, same species rivals. The skeletal shows high spines above the shoulders and a long, straight neck. It looks like it may have been adapted to lock horns and push like ceratopsians or many ruminants today. 
No hadrosaur that we know of had crests that could double as breathing tubes or snorkels; the famous Parasaurolophus' crest was seemingly used to produce sounds, and as a visual display (apparently males had the long crests, whereas female's were short and more rounded; the males would've have the louder call). The airways do pass through the crest but there's no opening on the tip, and the orientation also would make it impractical as a snorkel even if the orifice was present.

Adam Khor

This one is really cool!

https://www.nature.com/articles/s41598-018-37754-6.pdf

Adam Khor

Triassic archosaur Smok had tyrannosaur-like bite

Crunched bones and ate them like it was nothing.

https://www.nature.com/articles/s41598-018-37540-4?fbclid=IwAR2mjsECD8CWpdecKxG6WAniuloVyhV6LJXE20r0Kb5POdzyGSV890mSDkU

Adam Khor

Gnathovorax, a new herrerasaurid from Brazil. It honestly looks a lot like Herrerasaurus proper, wouldn´t be surprised if it's reclassified as such eventually.

https://blogs.scientificamerican.com/laelaps/stunning-skeleton-reveals-early-carnivorous-dinosaur/

Adam Khor

Strange erythrosuchids found to have proportionally immense heads, much larger than any dinosaur's:

https://phys.org/news/2019-11-ancient-komodo-dragon-like-animals-proportionally.html

Insect Overlord

It looks like Gon from the old Tekken games!

Adam Khor

A new Thalattosaur (Triassic marine reptile) from Alaska:

http://www.sci-news.com/paleontology/gunakadeit-joseeae-08088.html

Adam Khor

The Triassic archosaur Scleromochlus , variously portrayed until now as a bipedal runner or hopper (like a kangaroo or a jerboa), is found to have been a quadrupedal hopper not unlike a frog:

https://peerj.com/articles/8418/

Adam Khor

Triassic archosaur named after Tolkien character:

https://www.natureworldnews.com/articles/43635/20200409/new-fossil-reptile-species-discovered.htm

The animal is a new species named Elessaurus gondwanoccidens, after Elessar Telcontar, King Aragon II's chosen name, who was also known by his nicknames Longshanks and Strider. Aragorn is a character in the Lord of the Rings series written by J.R.R. Tolkien. Elessar, in the fictional Elvish language invented by Tolkien, means "elf-stone." The scientists think that the name is apt also because the reptile had notably long legs, which brings to mind Aragorn's nicknames.

The creature would've been related to the relatively better known Tanystropheus, notable for its incredibly long neck:

Adam Khor

Tiny (10 cm tall) archosaur from Triassic Madagascar. It was an ornithodiran, that is, closely related to both dinosaurs and pterosaurs.

https://www.pnas.org/content/early/2020/07/01/1916631117?fbclid=IwAR1VeJmiWRogJlxD02sPtiGlyDrHK3WUqQSAl6GdVpOiB3mKXL0SUsWpqM4

Adam Khor

Iconic Triassic reptile Tanystropheus, famous for its long neck, found to be two separate species; the small individuals are found to be fully grown rather than young as previously thought, and named T. hydroides. It seems their different size and dentition allowed for both species to coexist without competing with each other:

https://phys.org/news/2020-08-fossil-mystery-super-long-necked-reptiles-ocean.html

Adam Khor

Interesting talk about Triassic weirdness!

https://www.youtube.com/watch?v=R8WF2nLcMhA&feature=emb_logo

Adam Khor

Brevicaudosaurus, a small nothosaur with a very short tail and adaptations for buoyancy and keen underwater hearing:

http://www.sci-news.com/paleontology/brevicaudosaurus-jiyangshanensis-09001.html