Masquerain is a moth, not a mosquito. This is further evidenced by the fact that Masquerain lacks obvious features of the mosquito, including the characteristic piercing proboscis. It would be incredibly unusual for Game Freak to create a Pokemon that actually doesn't carry the trademark features of the animal it's based on.
Chipmunk Pachirisu, sort of.
Squirrels are not chipmunks. They're related, but it's like saying all wolves are dogs.
Squid (There's an octopus, but it's not the same.) Tentacruel, it is sometimes referred to as a squid. <_<
Tentacruel is a Portuguese man o' war, not a squid. They're not actually related. (I've personally never heard it referred to as a squid. At most, a jellyfish.)
A number of parasites (worms, ticks, fleas, et cetera -- even leeches) Parasect. XD
Parasect represents a parasitic mushroom, not the entire umbrella of parasites, which include tons and tons of different, diverse species, so saying Parasect covers all parasites is a lot like saying Beedrill represents all insects. For example, there's a number of worms (tape worms, for example), mites, flukes, and even molds that Parasect just can't represent as just a bug infected with a fungus.
How is Purugly not a tiger? XD
It's a tiger
cat, not a tiger. Similar name, but they're actually different animals. The tiger cat is more closely related to the ocelot, in a completely different genus.
Sorry. A bit of a science geek when it comes to animals. ^_^;
