#shringasaurus indicus

By Stolp

Etymology: Horned Reptile

First Described By: Sengupta, Ezcurra & Bandyopadhyay, 2017

Classification: Biota, Archaea, Proteoarchaeota, Asgardarchaeota, Eukaryota, Neokaryota, Scotokaryota Opimoda, Podiata, Amorphea, Obazoa, Opisthokonta, Holozoa, Filozoa, Choanozoa, Animalia, Eumetazoa, Parahoxozoa, Bilateria, Nephrozoa, Deuterostomia, Chordata, Olfactores, Vertebrata, Craniata, Gnathostomata, Eugnathostomata, Osteichthyes, Sarcopterygii, Rhipidistia, Tetrapodomorpha, Eotetrapodiformes, Elpistostegalia, Stegocephalia, Tetrapoda, Reptiliomorpha, Amniota, Sauropsida, Eureptilia, Romeriida, Diapsida, Neodiapsida, Sauria, Archosauromorpha, Crocopoda, Allokotosauria, Azendohsauridae

Status: Extinct

Time and Place: Between 247.2 to 242 million years ago, in the Anisian of the Middle Triassic 

Shringasaurus is known from the Denwa Formation in Madhya Pradesh, India 

Physical Description: Shringasaurus is a very strange looking reptile (befitting of the allokotosaur title), and basically looks like one of those retro ‘slurpasaurs’ from those old dinosaur movies where they just glued horns onto an iguana. At around 3–4 metres long, Shringasaurus was pretty large for a Middle Triassic archosauromorph, and could have potentially stood tall enough to look you in the eye. Shringasaurus had some very unusual proportions, with a small blunt-snouted head on a long, very thick neck attached to some very deep shoulders with tall withers over them. These chunky forequarters contrast with its rear end, with proportionately small hips and a tail that is relatively short compared to other stem-archosaurs. Of course, its most famous features are its bizarre horns over its eyes. These are remarkably similar to the horns of ceratopsid dinosaurs like Triceratops, and are yet another fabulous example of the Triassic doing everything dinosaurs did first. These horns can be as tall as the skull again in large individuals, and curve to face up and forwards. These horns were proportionately smaller in younger animals, and so likely grew in as they matured. Interestingly, one juvenile specimen lacks horns at all, even though a similar sized specimen has them, suggesting that some Shringasaurus, possibly females, didn’t have them. Even on closer inspection Shringasaurus is weird. For instance, it has palatal teeth like some other reptiles, but lots of them, and they’re all shaped exactly like the teeth on the edges of its jaws. No other reptile besides it and its close relative Azendohsaurus have teeth like that. Just imagine how that would look when it opened its mouth.

Shringasaurus embodies the typical azendohsaurid body plan of combining bizarrely ‘advanced’ sauropod-like traits with those of more ‘primitive’ archosauromorphs. Its long neck and small head has obvious superficial similarities, but features of its jaws and teeth are so sauropod-like that they’re only seen in sauropods themselves and azendohsaurids like Shringasaurus—yet another remarkable example of convergent evolution in these animals. Features of its arms are similar to sauropodomorphs too, but its posture was decidedly more ‘primitive’ than them. Its back legs sprawled completely, like those of a lizard, and while the front legs weren’t anything as upright as sauropods, they may still have been held more off the ground in a sort of semi-sprawl than the back ones. This would have given Shringasaurus a sloped back and raised the head and neck higher above its shoulders, so in a way it was still superficially sauropod-like. With horns.

Diet: Shringasaurus was clearly a herbivore from the shape of its teeth, which are leaf-shaped and serrated (indistinguishable from herbivorous dinosaur teeth, infact). The teeth and jaws of its close relative of Azendohsaurus have been studied in detail, and suggest it preferred feeding on the softer parts of plants like leaves rather than tough stems and branches. Shringasaurus had similar teeth, so it likely fed on soft vegetation also. Quite how it used its freaky palatal teeth is anyone’s guess.

Behavior: Not much can be said for sure about its behaviour, but since so many Shringasaurus individuals were found together of different ages, it’s possible that they lived in mixed-aged herds. Sexual dimorphism, if really present, would be a good indicator that the horns were used at least for display, but like the horns of ceratopsids and living bovids it’s also possible they were used in combat, locking their horns in jousts to settle disputes over food, mates, territory, or anything else they might have been grumpy over. The shape of the horns in particular implies they were mostly likely used for this kind of wrestling.

Ecosystem: Shringasaurus  co-existed with a decent variety of other typical mid-Triassic animals in the Denwa Formation. Other large herbivores included two dicynodonts, one a stahleckeriine and the other more like the older Kannemeyeria, as well as an early rhynchosaurid. No less than four temnospondyl amphibians are known from there, including the predatory Cherninia and Paracyclotosaurus crookshanki, a brachyopoid (think Koolasuchus), and a long-snouted gharial-like trematosaurid. The extinct lungfish Ceratodus was also swimming around here too. Shringasaurus was one of the largest animals known in this ecosystem, and probably would have only rubbed shoulders with the large stahleckeriine dicynodont for food sources, browsing on tall, lush plants out of reach of the other herbivores. The environment was a broad, semi-arid floodplain with slow meandering rivers, subject to seasonal rainfall and droughts that may have periodically dried up rivers and ponds.

Other: Shringasaurus belongs to a recently recognised group of archosauromorphs called Allokotosauria, the “strange reptiles”, which includes other peculiar stem-archosaurs like Trilophosaurus and bizarre Teraterpeton. Allokotosaurs all appear to be herbivores, and can be characterised by their strange teeth, but they’ve all got different types of them! Shringasaurus and other azendohsaurids all have jaws full of teeth (including the roof of the mouth) that look just like herbivorous dinosaur teeth. The resemblance is so uncanny that Azendohsaurus was considered to be a dinosaur for decades before the rest of its body was discovered. Trilophosaurids meanwhile have a characteristic beak, which in the unique case of Teraterpeton is so long and pointed that it vaguely resembles an anteater, and their teeth are cusped and interlocking for shearing leaves.

Early archosauromorphs used to be thought of as mostly carnivores and insectivores, while the role of large herbivores was dominated by the synapsid dicynodonts in the Early and Middle Triassic, with archosaurs like dinosaurs and aetosaurs, as well as the rhynchosaurs, only taking over in the Late Triassic. Allokotosaurs like Shringasaurus demonstrate that this was wrong, and that stem-archosaurs were just as capable of being derived herbivores capable of competing with synapsids in the Middle Triassic just as well as the later derived rhynchosaurs and archosaurs, including at large sizes as big as Shringasaurus. Intriguingly, there’s evidence to suggest that Azendohsaurus was endothermic to some degree, i.e. warm-blooded, and given their close relationship it’s probable that Shringasaurus was too. This would make azendohsaurids like Shringasaurus some of the earliest stem-archosaurs to have been warm-blooded!

~ By Scott Reid

Sources under the Cut

#Archovember Day 13 - Shringasaurus indicus

Shringasaurus is the reason I expanded Archovember to include other archosauromorphs. I just had to draw this strange creature.

Hailing from India, Shringasaurus had two ceratopsian-like horns, a long neck, and a humped back. It was about as large as a tiger, with an estimated length of 9.8–13.1 feet. Despite this, it was a herbivore, and may have filled the role of the large-bodied, high-browsing plant eater of it’s time.

As their skull fragments show a lot of variation in horn size and length, one skull even lacking them entirely, it’s suggested that Shringasaurus was sexually dimorphic, with the females perhaps lacking horns.