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Description
Postosuchus politely lets other scavengers know that she called dibs on the giant meat thing that washed up; yes, all fifty-plus tonnes of it.

Either that or she's acting out that one scene from the movie Alien, one or the other.

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Mid Norian (215 MYA), Southern California

Animal Species

Shastasaurus (?Shonisaurus) sikanniensis (from Sikanni [Mount] Shasta/(?[Shoshone Mountains]) lizard)- a species of primitive ichthyosaur known from the mid Norian of British Columbia, and one of the largest known marine reptiles to have ever lived, measuring twenty-one metres in length. S. sikanniensis may well have been the largest animal to have ever evolved up to that point in Earth's history, and fragmentary remains suggest later in the Triassic even larger ichthyosaurs may have existed; only the largest sauropods and baleen whales reached proportions that rivaled the most massive ichthyosaurs. However, at the end of the Triassic, the gigantic ichthyosaurs died out (although some Early Jurassic forms still got pretty big); only the smaller dolphin-like forms would survive into the Jurassic. It's under debate whether S. sikanniensis is a species of Shastasaurus or Shonisaurus, but in either case, it is reasonably certain that it was a specialized ichthyosaur; it was completely toothless with a slender, narrow body, and may have fed by ram-feeding, hunting by swimming through swathes of fish or cephalopods with its mouth open. The other Shastasaurus species are known from the Carnian of California and southern China (although that species may also be its own genus, Guanlingsaurus), and although also very large, are much smaller than S. sikanniensis; the other Shonisaurus species is known from the mid Norian of Nevada.

Postosuchus kirkpatricki (Kirkpatrick's crocodile from Post)- a species of large rauisuchid from the Norian of Arizona and Texas, and likely the apex predator of the Chinle Formation. It was the region's largest known terrestrial predator, reaching four to five metres in length and up to three-hundred kilograms, far larger than any of the dinosaurian carnivores it coexisted with (although some phytosaur species were larger). The "rauisuchians" were, by large, the dominant land carnivores of Earth during the Mid to Late Triassic, replacing the earlier erythrosuchids and were themselves replaced by theropod dinosaurs when they became extinct at the end of the Triassic. Coincidentally, Postosuchus somewhat resembled the layman's impression of a generic carnivorous dinosaur, with a robust skull filled with dagger-like teeth, a scaly armoured hide, and probably walking erect on its hindlimbs.

Chindesaurus bryansmalli (Bryan Small's ghost/Chinde [Point] lizard)- a species of herrerasaurid dinosaur from the mid Norian of the American Southwest, known from the fragmentary remains of multiple specimens. From what can be told, it was a typical species of herrerasaurid, a medium-sized predator, probably reaching about two metres in length and fifty kilograms in weight. It is one of the few herrerasaurids known from outside South America (the even more poorly-known Caseosaurus may be synonymous with Chindesaurus), and also one of the youngest members of the group; no herrerasaurid fossils are known that are definitely younger than the Norian, and they did not leave any known later descendants, leaving them as a short-lived dead-end clade. Didn't even last ten million years, what a bunch of chumps.

Dromomeron gregorii (Gregory's running femur) - a species of biped dinosauromorph from the Norian of Texas and Arizona that reached about one metre in length. It was a close relative of true dinosaurs; indeed, Dromomeron probably would have greatly resembled a small theropod in life, being a small, lightly-built biped with long hindlegs and tail. One study even suggested that Dromomeron (the sister species D. romeri at least) was the juvenile stage of the contemporary theropod Tawa, but this is not strongly supported and rejected by most. Dromomeron itself is otherwise not a particularly interesting animal, likely being an active predator of insects and other small animals that may have scavenged on occasion, although the fact that it coexisted alongside true dinosaurs so late into the Triassic is evidence that dinosaurian conquest was a gradual process.

Indeterminate pterosaurs- pterosaurs are unknown from the Triassic of North America, and as a whole are scarce from Triassic formations, being only definitely known from Europe (a few extremely fragmentary remains from North America have been assigned as possibly pterosaurian, but they are highly dubious). The appearance of pterosaurs during the Triassic as a whole is something of a mystery, as it's basically summed up as they didn't exist and then suddenly they did, with no known transitional forms to shed light on the enigma. Whether this means pterosaurs were not widespread during the Triassic or they simply weren't preserved well on other continents is unknown, but for the purpose of this illustration I've decided the latter because it looked better to have something in the air. (ignore the fact they look like evil sky clowns) The species is hypothetical, but they're based on basal pterosaurs such as Austriadactylus and Preondactylus, the former of which lived at about the same time as this scene but in... guess.

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Despite being some of the most massive marine animals that ever lived, giant ichthyosaurs rarely get any attention at all. The largest known ichthyosaurs are far larger than the biggest known mosasaurs or plesiosaurs, which may have approached fifteen metres at best, but several species of ichthyosaur reached or exceeded those measurements long before those species evolved. Alas, this is probably largely in part because Shastasaurus and its ilk didn't have big teeth, and therefore wouldn't have been as ferocious-looking or cool as guys like Liopleurodon or Tylosaurus, instead they looked like big fat dolphinosaurs with no/tiny teeth. Giant Triassic macropredatory ichthyosaurs also existed once but they're much more obscure and they seemingly died out pretty quickly. Ichthyosaurs didn't recover much of their Triassic diversity after the Tr-Jr extinction event, never really moved past the dolphin-lizard form after the Early Jurassic, and then they just sorta died in the middle of the Cretaceous; they're like that guy who peaked in high school.

A little bit of artistic license was used here, besides the aforementioned imaginary pterosaurs, none of the species here are technically known from the location where the scene is supposed to take place (California). However, I considered it to be close enough to the locations of the different species to still be possible, as Postosuchus, Dromomeron, and Chindesaurus are all known from a neighbouring state (Arizona), and an earlier species of Shastasaurus is known from California, as well as the reasonable assumption that such a large marine animal species would have a wide range similar to living marine megafauna and therefore could be found in different regions. At the time, most of California was submerged beneath a shallow sea along the continental shelf of eastern Pangaea, and the coast wouldn't have been too far from the more inland Chinle Formation, which at the time was still a relatively wet and moist environment most of the time, although it was beginning to undergo gradual aridification.

Another minor case of artistic license I didn't notice until I had started was that Shastasaurus was actually pretty narrow for its size; its ribcage would have only been about two metres wide in the biggest individuals (still more than roomy enough for a Postosuchus to hole up inside no problem). I fixed it a bit before the drawing was finished but it still looks a little wide... so just imagine this dead one is propped up on a sand dune at a slope and just looks a bit wider than it really is, and then it works okay.

---

EDITED: no barnacles now, turns out they didn't exist, even more so than the pterosaurs, also Postosuchus is slightly messier, since it's kind of moist in these ichthyosaurs.

NOTE FROM THE FUTURE: a Triassic North American pterosaur was described so ignore that part in the "indeterminate pterosaurs" description (but it lived after the Chinle Formation so this is still okay).

Description
Postosuchus politely lets other scavengers know that she called dibs on the giant meat thing that washed up; yes, all fifty-plus tonnes of it.

Either that or she's acting out that one scene from the movie Alien, one or the other.

---

Mid Norian (215 MYA), Southern California

Animal Species

Shastasaurus (?Shonisaurus) sikanniensis (from Sikanni [Mount] Shasta/(?[Shoshone Mountains]) lizard)- a species of primitive ichthyosaur known from the mid Norian of British Columbia, and one of the largest known marine reptiles to have ever lived, measuring twenty-one metres in length. S. sikanniensis may well have been the largest animal to have ever evolved up to that point in Earth's history, and fragmentary remains suggest later in the Triassic even larger ichthyosaurs may have existed; only the largest sauropods and baleen whales reached proportions that rivaled the most massive ichthyosaurs. However, at the end of the Triassic, the gigantic ichthyosaurs died out (although some Early Jurassic forms still got pretty big); only the smaller dolphin-like forms would survive into the Jurassic. It's under debate whether S. sikanniensis is a species of Shastasaurus or Shonisaurus, but in either case, it is reasonably certain that it was a specialized ichthyosaur; it was completely toothless with a slender, narrow body, and may have fed by ram-feeding, hunting by swimming through swathes of fish or cephalopods with its mouth open. The other Shastasaurus species are known from the Carnian of California and southern China (although that species may also be its own genus, Guanlingsaurus), and although also very large, are much smaller than S. sikanniensis; the other Shonisaurus species is known from the mid Norian of Nevada.

Postosuchus kirkpatricki (Kirkpatrick's crocodile from Post)- a species of large rauisuchid from the Norian of Arizona and Texas, and likely the apex predator of the Chinle Formation. It was the region's largest known terrestrial predator, reaching four to five metres in length and up to three-hundred kilograms, far larger than any of the dinosaurian carnivores it coexisted with (although some phytosaur species were larger). The "rauisuchians" were, by large, the dominant land carnivores of Earth during the Mid to Late Triassic, replacing the earlier erythrosuchids and were themselves replaced by theropod dinosaurs when they became extinct at the end of the Triassic. Coincidentally, Postosuchus somewhat resembled the layman's impression of a generic carnivorous dinosaur, with a robust skull filled with dagger-like teeth, a scaly armoured hide, and probably walking erect on its hindlimbs.

Chindesaurus bryansmalli (Bryan Small's ghost/Chinde [Point] lizard)- a species of herrerasaurid dinosaur from the mid Norian of the American Southwest, known from the fragmentary remains of multiple specimens. From what can be told, it was a typical species of herrerasaurid, a medium-sized predator, probably reaching about two metres in length and fifty kilograms in weight. It is one of the few herrerasaurids known from outside South America (the even more poorly-known Caseosaurus may be synonymous with Chindesaurus), and also one of the youngest members of the group; no herrerasaurid fossils are known that are definitely younger than the Norian, and they did not leave any known later descendants, leaving them as a short-lived dead-end clade. Didn't even last ten million years, what a bunch of chumps.

Dromomeron gregorii (Gregory's running femur) - a species of biped dinosauromorph from the Norian of Texas and Arizona that reached about one metre in length. It was a close relative of true dinosaurs; indeed, Dromomeron probably would have greatly resembled a small theropod in life, being a small, lightly-built biped with long hindlegs and tail. One study even suggested that Dromomeron (the sister species D. romeri at least) was the juvenile stage of the contemporary theropod Tawa, but this is not strongly supported and rejected by most. Dromomeron itself is otherwise not a particularly interesting animal, likely being an active predator of insects and other small animals that may have scavenged on occasion, although the fact that it coexisted alongside true dinosaurs so late into the Triassic is evidence that dinosaurian conquest was a gradual process.

Indeterminate pterosaurs- pterosaurs are unknown from the Triassic of North America, and as a whole are scarce from Triassic formations, being only definitely known from Europe (a few extremely fragmentary remains from North America have been assigned as possibly pterosaurian, but they are highly dubious). The appearance of pterosaurs during the Triassic as a whole is something of a mystery, as it's basically summed up as they didn't exist and then suddenly they did, with no known transitional forms to shed light on the enigma. Whether this means pterosaurs were not widespread during the Triassic or they simply weren't preserved well on other continents is unknown, but for the purpose of this illustration I've decided the latter because it looked better to have something in the air. (ignore the fact they look like evil sky clowns) The species is hypothetical, but they're based on basal pterosaurs such as Austriadactylus and Preondactylus, the former of which lived at about the same time as this scene but in... guess.

---

Despite being some of the most massive marine animals that ever lived, giant ichthyosaurs rarely get any attention at all. The largest known ichthyosaurs are far larger than the biggest known mosasaurs or plesiosaurs, which may have approached fifteen metres at best, but several species of ichthyosaur reached or exceeded those measurements long before those species evolved. Alas, this is probably largely in part because Shastasaurus and its ilk didn't have big teeth, and therefore wouldn't have been as ferocious-looking or cool as guys like Liopleurodon or Tylosaurus, instead they looked like big fat dolphinosaurs with no/tiny teeth. Giant Triassic macropredatory ichthyosaurs also existed once but they're much more obscure and they seemingly died out pretty quickly. Ichthyosaurs didn't recover much of their Triassic diversity after the Tr-Jr extinction event, never really moved past the dolphin-lizard form after the Early Jurassic, and then they just sorta died in the middle of the Cretaceous; they're like that guy who peaked in high school.

A little bit of artistic license was used here, besides the aforementioned imaginary pterosaurs, none of the species here are technically known from the location where the scene is supposed to take place (California). However, I considered it to be close enough to the locations of the different species to still be possible, as Postosuchus, Dromomeron, and Chindesaurus are all known from a neighbouring state (Arizona), and an earlier species of Shastasaurus is known from California, as well as the reasonable assumption that such a large marine animal species would have a wide range similar to living marine megafauna and therefore could be found in different regions. At the time, most of California was submerged beneath a shallow sea along the continental shelf of eastern Pangaea, and the coast wouldn't have been too far from the more inland Chinle Formation, which at the time was still a relatively wet and moist environment most of the time, although it was beginning to undergo gradual aridification.

Another minor case of artistic license I didn't notice until I had started was that Shastasaurus was actually pretty narrow for its size; its ribcage would have only been about two metres wide in the biggest individuals (still more than roomy enough for a Postosuchus to hole up inside no problem). I fixed it a bit before the drawing was finished but it still looks a little wide... so just imagine this dead one is propped up on a sand dune at a slope and just looks a bit wider than it really is, and then it works okay.

---

EDITED: no barnacles now, turns out they didn't exist, even more so than the pterosaurs, also Postosuchus is slightly messier, since it's kind of moist in these ichthyosaurs.

NOTE FROM THE FUTURE: a Triassic North American pterosaur was described so ignore that part in the "indeterminate pterosaurs" description (but it lived after the Chinle Formation so this is still okay).