Living a sheardog's life

With the rise of a new trophic chain, geotters became the most important predators of Antarctica, taking the place of the now-extinct herdstalkers and wardrums. With virtually no competitors (except for one species of brontosparrow), they were able to flourish in a multitude of forms and ecology in just 6 million years, while retaining an overall similar appearance. We'll need more time to see where their true evolutionary path will lead.
Sheardogs, a lineage of cursorial geotters, occupy now most of the superpredator niches of Neopolarica: some species have specialized for high speed, like the chetter (Lutropes mediterranea), a solitary carnivore that dwells in the mediterranean scrubland. Thanks to their long tail they can rapidly change direction while running. They are brontosparrow-specialized predators, capable of taking down even subadult mediterranean brontosparrows by injuring their legs and throat. Despite its discrete size, chetters are often mobbed by several mesopredators, like the dusk sheardog (Nyctalicyon planicola), a jackal-sized geotter that hunts in packs. While being a quarter the size of a chetter, dusk sheardogs have a proportionally strong bite force that can break bones; thanks to this and their social life, these sheardogs can successfully hunt vertebrates as big as hogsters.  They are one of the most successful predators of Antarctica, being found from the subtropical to the cold temperate zone, inhabiting both grasslands and woodlands. They are extremely noisy and chatty mammals that communicate by using prolonged howls and yelps. 

Another successful species is the arboreal sheardog (Fortidon dendroscansoria), which possesses short limbs and a long body to better climb trees. They mostly prey on woodclimbers and rattrees but they can also pounce on terrestrial vertebrates; like leopards, they often move their kill on trees, safe from the mobbing dusk sheardogs. They form monogamous pairs with their partners, which rarely cooperate during hunting. They are the first sheardog species that don't build their den on the ground: they instead create leaf-made bedding inside hollow dead trees, where they raise their young every year. Pups are born relatively precocial for a carnivore, a useful adaptation to reduce infant mortality from falling.