A dead Allosaurus, a casualty of the Jurassic Impact.
Jurassic Impact is a speculative evolution project by Reddit user u/EpicJM detailing the evolution of life on Earth, in an alternate timeline where the asteroid that ended the Cretaceous had hit during the Late Jurassic instead.
Jurassic Impact can be viewed here.
Tropes
- Butterfly of Doom: Several clades were severely impacted by the Jurassic Impact.
- All dinosaurs, save for the heterodontosaurids, compsognathids and pseudobirds perish during the extinction event.
- Pterosaurs were hit especially hard, with only the anurognathids making it through the impact event.
- Angiosperms never had the chance to arise as the ancestors that led to them in our timeline were wiped out during the impact event, leading to strange plants dominating the ecosystems.
- The teleosts die out completely as the result of the last of three catastrophic anoxic events dubbed "Bad Water".
- The lepidopterans (moths, butterflies and kin) remain in the shadows of the kalligrammatids, butterfly-like insects that are the dominant pollinators of the post-Jurassic Impact world.
- Child Eater: While it's highly likely that a majority of life in the timeline does this, only two are specifically described in the project to do this: Odiodon, a monstrous eutriconodont from Africa reminiscent of leopards and other big cats, and Xystonoglossus, a cone snail-esque gastropod that uses its toxic harpoon-like radula to slaughter baby pterosaurs.
- Cute Owl: While not technically owls, a few of the anurognathids invoke this trope with their large eyes and short faces.
- Fantastic Fauna Counterpart: Due to convergent evolution, there is bound to be examples.
- The multingulates are herbivorous multituberculates that resemble ungulates, particularly artiodactyls.
- The brutotheres are large trunked multingulates that resemble elephants. Their ancestor, Dactylorhynchus, resembles a pig or tapir.
- The entelodryolestids resemble, you guessed it, the entelodonts.
- The aptly named Cricetosaurusnote is a small dinosaur that possesses a throat pouch, analogous to the cheek pouches that hamsters possess.
- The dryowhalesnote are, obviously enough, convergent with our timeline's cetaceans, but with some traits analogous to our timeline's manatees, such as the young ones breastfeeding from the mother's armpits.
- Even plants have their counterparts:
- Ephedra-like gymnosperms fill the role of grass, as the ancestors of what would've become the angiosperms of our timeline died out during the extinction event.
- The nothoflorans are non-angiosperm spermatophytes (seeded plants) which have evolved flowers to attract insects, not unlike the flowers we see in angiosperms. Notably, they have four petals for each flower, a number which no angiosperm has.
- The multingulates are herbivorous multituberculates that resemble ungulates, particularly artiodactyls.
- Giant Flyer: While not as large as the azhdarchids of our timeline, the horse-sized Dolorodraco halfordi dwarfs any known bird.
- Introduced Species Calamity: Scolionid multituberculates, insectivorous immigrants from Asia, drive the Laramidian termite eater Vermicofossor to extinction.
- Killer Rabbit: Plants of the Turonian and the Animals who Benefit, Part 2 has Sphaerognathus sarcosparassosnote that are cute and fluffy little nyctopterid anurognaths that have teeth similar to the bottom ones of a cookiecutter shark that they use to tear perfectly spherical chunks of flesh from larger animals among other things.
- Last of His Kind: In Hallowed Be Thy Name: The Last Ferravirgid, a male Vestopteryx caeruleus dies, bringing an entire clade, the Ferravirgids, down with him.
- Musical Theme Naming: Due to u/EpicJM being a fan of metal music, he likes to incorporate musical references in both his posts and the names of his creatures on numerous occasions.
- Names to Run Away from Really Fast: Many creatures have scientific names like these, including the following:
- Dolorodraco, meaning "Dragon of Pain"
- Monstrocanitherium, meaning "Monster Dog Beast"
- Cursobellator, meaning "Running Warrior"
- Diablosuchus, meaning "Devil Crocodile"
- Point of Divergence: The eponymous Jurassic Impact itself, where the asteroid that would have wiped out the non-avian dinosaurs in our timeline impacts the Earth in the Late Jurassic instead, changing the course of life.
- Toothy Bird: The pseudobirds, direct descendants of Archaeopteryx-like theropods, are flying dinosaurs that retain teeth. They also are the dominant "bird" clade of this timeline.
- Speculative Biology: The project shows how life could have evolved if the asteroid hit in the Jurassic period instead of the Cretaceous.
