The late Expansocene: 100 million years post-establishment

As we come to 100 million years after establishment of chiroptosphere, we take one final look at the continents. The southmost continent is now half-covered by year-round snow, much of which comes in the form of hostile tundra. The equatorial continent is supporting a thriving ecosystem of strange organisms not found anywhere else in the world. The northmost continent has settled for a temperate ecosystem with freezing and sweltering points on the north and south of the continent. It is here we say goodbye to the land ecosystems of chiroptosphere- but first, we must meet one more clade.

The fearozinos, the apex predators of the continent of Durios, have given rise to a new, strange form. A fearozino would occasionally be born with reduced or no claws. Being social animals, the fearozinos would still care and provide food for their unfortunate relative, and so these clawless predators would still survive to pass on their genes, although their numbers would always stay relatively low compared to their more capable relatives. This all changed, however, when one group of mostly clawless fearozinos figured out they could hunt for themselves after all- who needs claws when you can hold and throw a pointy stick?

Though they did have an advantage over their clawed cousins in that they could throw their weapons, they didn’t immediately outcompete their relatives. They slowly expanded their arsenal of tools, using rocks to get at bone marrow, using hide to keep themselves warm, and using materials like bone and rock to make their spears more powerful. Eventually, the bushfires of the savannah would teach them how to use their most important tool yet- fire. With fire, they could cook their meat, unlocking a lot more nutrients from the same amount of food. They could now afford to invest more and more energy into their brain, and they became more social and more clever. Their pattern recognition and memory skills developed into a taste for art and music. They sang about their legends, dyed their clothes, painted the walls of caves, carved sculptures, and dedicated rituals to their gods. These were people.

Though they superficially resemble humans and sport many intellectual and emotional similarities, chirosapiens are still different to humans. They are taller and more slender, and display less sexual dimorphism- though female’s hips are thicker on average, the difference is less pronounced than in humans, and the female’s breasts only appear when they are weaning. They have patterns on their skin, like stripes and freckles. They have retained less hair than humans, only having a little body hair on their upper arms, upper legs, and the top of their head. Like humans, there are different complexions of chirosapiens in different areas, that could be called races. Chirosapiens from the grasslands on the north of the continent tend to be lighter than those from the savannahs surrounding the equator. There are no chirosapiens with skin as light as some humans have evolved, as there are no environments on their home continent far away enough from the equator to facilitate this evolution.

Despite the fact they experience similar emotions to us, because of our shared mammalian heritage, they express these emotions very differently. They show affection by rubbing each other’s chests, and show romantic interest by massaging another’s crests. These crests, which are membranes attached to bony horns, are sexual display structures, meaning they are attractive to other chirosapiens. They display slight sexual dimorphism in these crests- the base of the female’s crest attaches to the base of the neck, making it smaller than the male’s crest, which attaches to the middle of the back. While humans rely mostly on the position of their eyebrows and mouth to read each other’s emotion, chirosapiens rely on the position of their ears and the openness of their eyes. Chirosapiens have more developed hearing and smell than humans, and less developed sight, so they rely on a different combination of senses. They use their excellent sense of smell to detect pheromones coming from other chirosapiens, that may mean a number of things- a chirosapien may unconsciously release pheromones when they are angry or aroused, or they may consciously decide to rub the scent glands in their cheeks against trees to signify to other chirosapien tribes that this is their tribe’s territory.

The chirosapiens had the same hunting strategy as their fearozino relatives, except they were better at it, with tools and better communication. As quickly as the fearozinos appeared, they started to disappear in droves. In the fight for apex predator on the continent of Durios, ultimately, a sapient species came out on top.

Phylogenetic charts

Size comparison of extant species

Additional illustrations

Thank you to my ig followers and the (mostly) wonderful people at r/speculativeevolution for making this project as rewarding as it was! Even if I'm no longer proud of it, I had a lot of fun making it and it taught me a lot about speculative evolution and animal anatomy. I would not be where I am today without Chiroptosphere!

More seed world content can be found here and here!