Tag: canidae

Spectember/Spectober 2024 #09: Big Bad Wild Dogs

@poshtearexdoodles asked for “African wild dogs evolved to fill the larger pack animal niche of lions”:

Although in this particular timeline the endangered and fragmented wild painted dogs in Africa didn’t survive far past modern times, that wasn’t the final extinction of the species – captive groups persisted, and after the [REDACTED] of humans an escaped population managed to carve out a niche for themselves in the grasslands of southern North America.

A shaded sketch of a speculative descendant of painted dogs. It's a large wolf-like animal with short thick hyena-like jaws, a mottled shaggy coat of fur, and and small hoof-like nails on its feet.

Their most notable descendant is Megainolycos poshtearexi. At nearly 1m tall at the shoulder (~3’3″) it’s one of the largest canids to ever exist, comparable to present-day lions in size and general ecology, with short thick bone-crushing jaws convergent with those of hyenas.

It also retains the complex variable coat coloration of its ancestors, with each individual having a unique disruptive pattern of black, white, and brown blotches.

Much like its ancestors it’s a highly social pack predator specialized for endurance hunting. Along with some surprisingly horse-like limb ligament morphology, its feet now sport hoof-like nails rather than claws, and it pursues prey over long distances to the point of exhaustion – mainly targeting the larger ungulates across its prairie habitat such as hogs, horses, bovids, and deer.

Spectember 2024 #01: Sea Dog

It’s September, it’s #Spectember, and I’m still plugging away at that big ol’ pile of speculative evolution idea submissions from a few years ago.

I will never be free.

Much like last year I’m not setting a definite posting schedule for this month; it’ll just be whenever and whatever I can manage to get done.

(Also, a reminder: I’m still not currently taking new requests!)

So let’s get started with an anonymous submission that requested a “swimming piscivorous canid”:

A shaded sketch of a speculative semi-aquatic descendant of modern short-eared dogs. It has an otter-like body with a long flat tail and four webbed feet, and a wide head with a long narrow toothy snout and small close-set eyes.

Descended from the short-eared dog (a species that in modern times already has partially-webbed paws and eats a large proportion of fish in its diet), Pelagicyon salsus is a 2m long (~6’6″) semi-aquatic piscivorous canid with a stocky body, short webbed limbs, and a long flattened tail.

The back of its skull is very wide, anchoring its thick neck musculature and accommodating huge cheekbones with powerful jaw muscles, but in contrast its snout is elongated and slender – a combination of features that allows it to sweep its toothy jaws through the water to rapidly snap at fish in a similar manner to gharials.

Most other members of its lineage inhabit freshwater rivers and swamps, but Pelagicyon is an unusual marine offshoot that has developed enough salt tolerance to swim, feed, and even drink exclusively in seawater.

Island Weirdness #56 — Cynotherium sardous

Despite being decent swimmers, canids are surprisingly rare in island ecosystems, only seeming to end up there when able to move over land connections with larger landmasses (or when brought there by humans). Even the most remote species, the recently-extinct warrah, is thought to have crossed over a short stretch of sea ice during the last glacial period.

So the existence of a unique canid on the Mediterranean islands of Sardinia and Corsica is quite unusual.

The Sardinian dhole (Cynotherium sardous) was a small fox-sized canid, just 50cm tall at the shoulder (1’8″), related to the modern African wild dog and dhole. It was probably descended from the much larger wolf-like Xenocyon, which would have been able to reach Sardinia-Corsica during the early-to-mid Pleistocene about 1.2 million years ago, at a time when lower sea levels connected the island to the European mainland via Tuscany.

Isolated with very little large prey, it instead evolved to specialize in hunting small fast-moving animals, flattening its body low to the ground while stalking in a similar manner to modern foxes or Ethiopian wolves. Powerful shoulder muscles allowed it to launch into sudden high-speed lunges, and it had an especially strong flexible neck that would have been used to grab at its zig-zagging targets and shake them to death.

Cynotherium went extinct sometime in the early Holocene, around 11,000 years ago, after the arrival of humans on Sardinia and Corsica.

The earliest definite human remains on Sardinia are at least 20,000 years old, and while it’s unclear if those were permanent settlers it still seems like Cynotherium was able to deal with the effects of a human presence for several thousand years, probably due to its main prey (the Sardinian pika) also surviving at the time. So its disappearance may have been caused by a combination of problems that slowly whittled away at its population, like the warming climate, gradual habitat destruction, and competition from introduced predators like feral dogs — or possibly even new diseases caught from them.