>>4082988 (OP)Something cool I'd like to mention is how the body shape of dolphins is so efficient for marine animals that it has appeared in two, unrelated cases of convergent evolution, with the Ichthyosaurus, a reptile with quite literally every dolphin feature, and, well, the cetaceans of contemporary day, safe to say if it's a marine environment you'll probably see a dolphin-like organism show up at least once.