Primitive Animals?

Some kids in the UK found a three-headed frog in their nursery school garden. Interesting. Frogs are supposedly an indicator species - amphibians in general are sensitive to toxins and other pollutants and environmental problems, so if amphibian species start having trouble, that could indicate larger problems that will soon affect the rest of an ecosystem. But what's up with this quote?

Mike Dilger, from the BBC Natural History Unit, said: "I have never seen anything like this.

"Frogs are primitive animals - so the occasional extra toe is not that unusual. But this is very unusual."

I thought that current science wisdom is not to rank organisms as though some are more "primitive" while others are more "evolved" - because all the species on Earth today have had millions of years to adapt specifically for their own particular niche. And even then, I've never heard "primitive" linked to "often born with extra limbs" before. Hmmm.