Roy (@roygattero) requested “ratel becoming the new african big predator”:
Perforictis royi is the latest in the long and venerable tradition of various synapsid lineages discovering the ecological niche of “big stabby saber-teeth“.
A descendant of the modern ratel/honey badger, it stands around 80cm tall at the shoulder (~2’8″), and convergently resembles the feline-like build of some of its more ancientrelatives. Inhabiting the tropical forests of the rifted-off island continent of East Africa, it’s an ambush predator specializing in tackling larger prey – primarily ungulates and primates, but also occasionally giant rodents and hyraxes.
Usually cooperatively hunting in mated pairs, these mustelids stalk close to their targets before attacking, with one individual focusing on toppling and immobilizing their target while the other positions itself to deliver a swift precision killing bite to the throat with its saber-teeth and powerful neck musculature.
Perforictis scent marks its territory using extremely pungent secretions from its anal pouch rubbed onto vegatation, along with making loud scream-like vocalizations.
Descended from an arboreal offshoot lineage of the modern least weasel, Maximagale gaycooniei is a bizarre mustelid that appears to have converged on the lifestyle of ambush-hunting tree snakes, evolving in northern latitudes where actual snakes are largely absent.
Growing to about 1m long (3’3″), it’s not truly legless but its limbs are all reduced down to tiny vestigial single-clawed spurs, which are used to help anchor its body while climbing and as claspers during mating. It moves around with a distinctive inchworm-like looping gait, alternating grasping and releasing with its front and hind spurs.
Its build is bottom-heavy, with most of its mass concentrated in its thicker back end, and its tail is semi-prehensile. It clings to trees with its body bunched up, camouflaged with cryptic coloration, and rapidly whips its long flexible front half out to snap its powerfully-muscled jaws at prey – such as insects, birds, lizards, frogs, small mammals, and pretty much anything else that comes within its reach.
It will also opportunistically raid the nest of birds and arboreal mammals.
Due to the less frequent meals its ambush-hunting tactics provide, it has a much slower metabolism than its ancestors, and it conserves energy with daily periods of torpor and longer hibernation during the colder months of winter. It has also retained its ancestor’s tendency to seasonally shrink its brain size to reduce energy requirements even more.
The Mediterranean island of Crete had very few predators during the Pleistocene, with most being birds of prey. And with the terrestrial carnivore niches in the ecosystem left vacant, it was a semi-aquatic mammal and an owl that ended up taking advantage of that opportunity.
Neither were large enough to threaten the dwarf elephants and hippos, and don’t even seem to have habitually eaten even the smallest of the miniature giant deer. Instead these Cretan predators focused much more on the smaller land vertebrates on the island, preying on birds, shrews, rodents, amphibians, and reptiles.
Lutrogale cretensis
Lutrogale cretensis (previously known as Isolalutra cretensis) was a close relative of the modern smooth-coated otter. It was about the same size as its living cousin, around 1m long (3’3″), but had stronger jaws and chunkier limbs.
Its skeleton shows features associated with walking and running more than swimming, and it seems that this was something of a “land otter” — still able to swim, but spending most of its time on land similar to the modern small-clawed otter.
Shellfish were likely still the main part of its diet, indicated by its crushing teeth. But it probably also regularly ate whatever small terrestrial vertebrates it could catch, since more aquatic otters are already known to prey on those types on animals when they can.
Athene cretensis
Athene cretensis was yet another weird island owl, but this time not a descendant of a Strix or Tyto species. Instead this owl was descended from the Eurasian little owl — except it had become much much larger.
It stood around 60cm tall (2′), over three times bigger than its living relative. Its legs weren’t quite as long as those of the modern burrowing owl, but they were still proportionally much longer than those of little owls and show adaptations for terrestrial movement. Little owls already sometimes chase down prey on foot, and Athene cretensis was probably even more of a ground-based hunter, convergently similar to the Hawaiian stilt-owls and the Cuban terror owls.
Preserved pellets show that it ate small mammals and birds, mainly large mice.
Its wings were still quite large, and it was probably also a good flier — and may even have spread over to some of the Dodecanese islands to the east of Crete, since a wing bone closely resembling that of Athene cretensis has been found on Armathia.
Both of these predators seem to have disappeared around the end of the Pleistocene, at the same time as many of the other native Cretan species about 21,500 years ago. Much like the situation with Candiacervus, this may have been a result of a combination of a rapidly shifting climate and the presence of humans disrupting the already fragile island ecosystem.
Along with its miniature mammoths, the Mediterranean island of Sardinia (and neighboring Corsica) had an unusually large amount of endemicmustelids during the Pleistocene and early Holocene. There were at least four different otters — probably all descended from a single species of Lutra — that occupied various ecological niches in both the rivers and the coasts, and also an enigmatic grison-like terrestrial species.
Megalenhydris barbaricina was the largest of the Sardinian-Corsican otters, reaching lengths of over 2m (6’6″), slightly bigger than the modern South American giant river otter. Its crushing teeth indicate it specialized in crunching through hard-shelled invertebrates like molluscs and crustaceans, and its highly flexible backbone and flattened tail suggest it was a strong swimmer that may have been even more aquatic than most other otters.
It was possibly an equivalent of the modern sea otter, spending most of its time in the water, although it’s not clear whether it was a river or marine species.
Dating on the one known partial skeleton of Megalenhydris is uncertain, but it may be late Pleistocene to early Holocene in age, between about about 70,000 and 10,000 years old. Unfortunately this puts it within the same age range as the arrival of humans on Sardinia and Corsica, and its extinction may have been a direct result of being hunted for its meat and pelt.
