Imagine the scene, some 250 years ago in St. Petersburg, Russia, when a German naturalist held a small, spiky ball-shaped specimen in his hand, wondering if he had discovered a new and rather unusual species of fish. In fact, what he held was a sunfish larva - it was equally unimaginable to naturalists back then as it is to us today that these rotund Pokémon look-alikes could be at all related to the giant sunfish, which would require them to increase their weight by a factor of not hundreds, not thousands, but millions, to reach the size of a car.
Image: An adult sunfish with a car as comparison; Steve O'Shea
After all, what makes sunfish recognisable is precisely their enormous size and unusual body shape, resembling huge pancakes with wings, and a peculiar “rudder” where you would expect a tail. They meet the public more often than you would think when they wash up on beaches in New Zealand, confounding onlookers who aren’t quite sure what they’re looking at.
Image: Mola larvae; Amy Rose Coghlan
Unlike their somewhat grotesque-looking parents, the larvae are downright adorable, with a perpetual wide-eyed look of innocence and surprise. These early life stages have not been studied in much detail, making identifying Mola larvae to species-level a real challenge. They are seldom encountered and when they are, they are most often fixed in formalin in preparation for museum collections, which makes examining the DNA to identify the species difficult.
Background image: Obtaining a sample for genetics from a sunfish; Jonathan Anderson