The worm is from phylum annelida. Both animals are tough to find in the tundra, but they are there. Also, mosquitoes and black flies are located in the tundra and are arthropods. Its feet are made for the ice. Its blubbery skin is adapted to suit the cold weather.
Penguins have fat under their skin to make themselves even warmer.
Unfortunately for the penguins, their blubbery skin is a target for hunters. One organism that is well adapted for the tundra is the lichen. Lichen can tolerate hostile environments like deserts and polar regions. Lichen do not handle pollution well. They are killed very easily by it.