#cynodont

Probelosodon (2026), foil lithograph, edition of 2+2AP

the first print from my residency at Women's Studio Workshop! this is based on some drawings in my sketchbook from a museum visit; initially just a test for the litho technique i would go on to teach during the Art-in-Ed classes that were part of the program, but the print came out so well that i decided to make a small edition of it.

Lystrosaurus

Lystrosaurus (Greek meaning “shovel reptile”) was a herbivore dicynodont that lived from the Lopingian (late Permian) to Early Triassic. Its fossils are known from South Africa, India, Russia, China and Antarctica. Lystrosaurus survived the Permian-Triassic extinction event, and went onto thrive in the early Triassic, at one point making up 95% of all terrestrial Vertebrates.

Lystrosaurus is notable for dominating southern Pangaea for millions of years during the Early Triassic. At least one unidentified species of this genus survived the end-Permian mass extinction and, in the absence of predators and herbivorous competitors, went on to thrive and re-radiate into a number of species within the genus, becoming the most common group of terrestrial vertebrates during the Early Triassic; for a while, 95% of land vertebrates were Lystrosaurus. This is the only time that a single species or genus of land animal dominated the Earth to such a degree. A few other Permian therapsid genera also survived the mass extinction and appear in Triassic rocks—the therocephalians Tetracynodon, Moschorhinus and Ictidosuchoides—but do not appear to have been abundant in the Triassic; complete ecological recovery took 30 million years, spanning the Early and Middle Triassic…

Text via: Wikipedia

Cynodonts were one of the few lineages of synapsids ("protomammals") to survive through the Great Dying mass extinction into the Triassic. And while a major branch of cynodonts known as probainognathians would eventually go on to produce the ancestors of modern mammals, for much of the Triassic a separate branch called cynognathians were initially much more diverse and numerous.

Exaeretodon argentinus was a large traversodontid cynognathian, growing up to about 1.8m long (~6'), known from the Late Triassic (~234-227 million years ago) of what is now northwestern Argentina. It was a low-slung animal with short stocky limbs, sprawling at the front and semi-upright at the back, and had a large head with a fairly short narrow snout and wide flaring cheekbones accommodating massive jaw muscles.

Although it it had large fang-like canine teeth, further back in its jaws wide molar-like grinding teeth show it was a specialized herbivore – at least as an adult. Different skull proportions in juveniles suggest that young Exaeretodon may have actually started out life as omnivorous or carnivorous, with jaws better suited for crushing hard-shelled invertebrate prey.

One Exaeretodon specimen shows evidence of severe rib injuries that would have hindered its mobility and made it very difficult to forage for food or avoid predators. But in this case those injuries were healed, suggesting this species may have lived in social groups that helped to protect each other.

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Cynodreaming 💤

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I Pseudosauropod paraxenos, mid triassic - Native to an unnamed island off the south-western coast of Pangea, Pseudosauropod might be the first large dinosaur in history. Descended from small insectivores that dispersed there through drifting it inhabits an island never reached by pseudosuchians or synapsids, which allowed those small creatures to quickly fill the megafaunal niche and become large herbivores. Despite it's close resemblance to sauropodomorphs it is actually a basal theropod hovewer at this point in time it hasn't been long since those two groups split. Ultimately an evolutionary dead end, it is nevertheless a forecast of things to come.

II Melisodon nakamuri, late jurassic - While almost all non-mammalian synapsids vanished at the end of triassic, few non-mammal cynodonts managed to make it through into the jurassic. Among them was a lineage of the very last cynognathids, still clinging on in Antarctica. As time passed, some of them found themselves on an isolated island chain off the southernmost continent. On the islands they flourished and diversified into many different niches, thriving long after the extinction of their brethren on the mainland. They survived up until the jurassic-cretaceous boundary, when environmental changes ultimately led to their demise, making them the last non-Probainognathian synapsids to have ever lived. Melisodon, a relatively large omnivore of the end jurassic is one of the last species in the lineage.

III Adamatherium kynodontis, mid cretaceous - Animal hailing from a sizeable island in eastern Tethis Ocean. This land has no non-avian dinosaurs, however it was reached by several mammals from few different clades, that dispersed there by drifting. With the limitations posed by archosaurs largely gone, small furry creatures quickly evolved to fill almost all available niches on the island. From weird specialised omnivores, through megafaunal grazers to apex predators. This small kingdom became a "cenozoic before cenozoic", showing how quickly animals can evolve and flourish if given a chance. Adamatherium is a herbivorous multituberculate, and the largest animal on the island. Reaching the size of a cow, it is the largest mammal to have yet existed, and it will only be matched after several tens of millions of years.

IV Balearosaurus parvus, late cretaceous - This small iguanodont is a fascinating case of convergent evolution to Balearic Island cave "goat" (a real, bizarre animal killed off by humans just few millenia ago). It's story began when their small island separated from the landmass of future Spain, isolating few animals there from the outside world. Balearosaur's ancestors found themselves in a very small place, with no predators and almost no competition, but extremely limited resources, which demanded extreme adaptations. Over time their legs became shorter and weaker, with the animal losing it's ability to run, as it would be an unneeded waste of energy in this predator free environment. Lack of predator also caused another adaptation - forward facing eyes, an unnerving sight in a herbivore. Due to very limited access to calories they became much smaller from their ancestors, and developed an extreme adaptation - ectothermy. With slower metabolism and body heat controlled by external temperatures the animal can conserve more energy, making it perhaps the only cold blooded dinosaur in history. Yet eventually the island moved closer to larger landmasses again, meaning it became available for frequent visits by large azhdharids. With a sudden reappearance of predators Balearosaurus vanished in just a few generations.

V Contritodactylus maxima, late cretaceous - It is much rarer for flightlesness to evolve in pterosaurs that it is in birds, but with the right conditions it can still happen. Contritodactylus is a giant flightless tapejarid, native to a large but really isolated island in the Pacific. It's ancestors were lightweight frugivores, caught in a tropical storm and carried off course into the fated land. Here they found themselves in a place with an abundance of food but basically no land predators big enough to pose a serious threat, maybe with an exception of some large lizards. The island was also the only food source within a flying range. Those conditions caused many descending species to lose their ability to fly, and fill land dwelling niches. Contritodactylus is a specialised browser, with it's massive beak used to strip branches of fresh leaves, pick and crush fruit and crack open nuts and seed pods. It is also the heaviest pterosaur on the planet at that particular time period.