Consider the crustacean Parhyale hawaiensis, a tiny crustacean with some interesting attributes.

 “It’s been called a ‘living Swiss army knife,’” said Dillon Cislo, the lead author of a study that appears in Nature Physics. “It has numerous different appendages and each one is uniquely specifiable by its size and shape. Furthermore, each one of these limbs has a very specific function.”

Their fascinating bodies and accessible growth conditions make these creatures a well-chosen model organism for developmental studies. But more than that, according to Cislo and UC Santa Barbara researchers Mark Bowick and Sebastian Streichan, their embryos are a window into the world of tissue morphogenesis, a field that seeks to understand how a mass of embryonic cells becomes the complex body parts of an adult organism. As a “direct developer,” or an organism that builds its adult form — albeit in miniature — as opposed to having a distinct larval form and undergoing metamorphosis, this crustacean is one to watch.