Cute line. Wish they weren't scrapped.
Without the context of a non-cut Pokemon like Karrablast, I can only so far when it comes to naming. Tani seems to mean some sort of gorge or mountain river. Not sure on anything except the last of the line, which literally has "King" in the name. I dunno Japanese that well, and someone better can try their own attempt to name them.
Physically, these guys resemble either conch snails, whelks, or cone snails.
Later in my research, I found that the culprit might be a species of land snails called Karaftohelix which may be found in the Kuril Islands, the same place where our wife can be found.
Name: Tanisu/Selsk (Karaftohelix Selskii, and setting up the naming scheme for the others.)
Type: Bug/Water
Abilities: Hydration/Shell Armor
Hidden Ability: Regenerator (or Corrosive?)
HP: 46
ATK: 44
DEF: 70
SPA: 54
SPD: 55
SPE: 38
>This Pokemon hides in the mud after it rains, keeping a watchful eye for its natural rival, Karrablast.
>If anything gets close to this Pokemon, it hides in its shell. This Pokemon feeds off plants that thrive in near ponds.
Name: Taniino/Selskorn (Selskii + Horn or Scorn)
HP: 59
ATK: 55
DEF: 95
SPA: 76
DEF: 66
SPE: 42
>This Pokemon protects its kin from dangerous Pokemon. It will often charge into battle without hesitation, and can often be found headbutting trees where Karratarch can be found.
>Karratarch is this Pokemon's natural rival. If it finds one in the wild, it will chase after them until they leave the area.
Name: Tanikingu/Selsking (Selskii + King)
HP: 71
ATK: 72
DEF: 123
SPA: 106
SPD: 78
SPE: 59
>Selsking rules over entire swaths of wetlands, making sure that no intruder impose upon their territory.
>This Pokemon is often found on the edge of wetlands, warring with Karratarch. Its venom can even break down their rival's steel horns.