First, I apologize for taking so long to reply! Also, I was having a non-drawing day yesterday; hence the slight lopsidedness of everyone.
The earliest recognizably paski ancestors were very small, nocturnal carnivores. Their eyes were large to absorb light and allow them to see at night. Their infrared pit organs were developed by this stage; these are a throwback from the first carnivorous mammals. Paski originated in plainsland and developed long legs to see over the grass.
Later paski ancestors began rearing up on their hind legs, possibly to attain a better view, possibly to free up their front legs for carrying objects, such as carcasses or tools. Their front paws gradually began changing from solely weight-bearing (three weight-bearing toes, two slashing dewclaws) to more hand-like (three grasping digits, a grasping thumb, and a slashing dewclaw). The pelvis angulation, thigh bone length, spinal curvature, and spine-skull connection angle began changing to fit a more bipedal locomotion, though it was some time before the paski ancestors gave up their quadrupedal way of life.
They also experienced a change in diet—becoming omnivores instead of pure carnivores. This prompted changes in their gut morphology to keep food in the gut longer so that plant material could be digested. Dentition changed as well, and eventually paski would lose their carnivorous double fangs. The switch in diet led to a change in circadian rhythm, and paski became diurnal. Their eyes remained large, developing their incredible long-range, high acuity vision to spot prey, friends, and enemies out on the plains. The rewiring of the brain needed to support the changes in vision led to a large decrease in their senses of taste and smell.
The first actual paski subspecies to form lived in temperate and Mediterranean-like environments. The temperate subspecies, Caandiki, started out brown like the “Neandertal Paski” above, but a mutation introduced the chinchilla coloration that is present in the vast majority of Caandiki. They are the only paski to have pink skin, the rest have dark brown skin. A group of Caandiki migrated to an arctic environment, and eventually formed the arctic subspecies, Pilasira. They developed thicker ribcages and limbs, long course hair, and large fat deposits to survive their harsh environment.
The Mediterranean-like subspecies, Takasira, should have dark brown skin, but I, uh, forgot. XD Their first offshoot, the Raatasira developed in a desert environment. They have the thinnest limbs, faces, and ribcages to facilitate heat loss. Raatasira often have nocturnal leanings, as nighttime was the safest time to food-gather in the desert. Most Raatasira have a little curl at the tip of the tail; the purpose of this is unknown. A very small population of Takasira took up residence on a tropical island and eventually developed into the oddest-looking paski subspecies, the Binasinga. Binasinga are short and stocky, with extra-long wattles, and have no horns and short tails. Quite a few of them have vestigial or missing secondary thumbs (dewclaws). Binasinga are few in number, and there are concerns of them becoming extinct. The Takasira went extinct some time before spaceflight was achieved; they were exterminated by the Raatasira.
Addendum: A great website on human evolution and the changes that we went through while we were evolving is Smithsonian’s What Does it Mean to be Human. They gave me some great ideas for how the paski might have started out.