For #invertefest, a spectacular specimen of one of my favorite invertebrates, the horseshoe crab Limulus polyphemus. These blue-blooded marvels have some of the coolest compound eyes in nature, *and* they produce compounds in their blood used to test for the presence of gram-negative bacteria. 🧪
cool!
In addition to the big compound eyes there in the middle, where you’d think eyes would be, they have several more - a little pair just in back of the big ones, three(!) in the middle in front, and two underneath, near the mouth. They *also* have light-sensing structures down the telson (the tail).
Ooh! Did not know about the light-sensing structures on the tail! TIL! link.springer.com/article/10.1...
I’ve always been partial to the unusual ways to see - evolution has resulted in so very many ways to deal with light!
Iirc they only can detect light/dark & motion. Keeping things on a need-to-know basis I guess.
I may have only skimmed the material, but it sounds analogous to our pineal gland?
Horseshoe crabs have those too - the three medial eyes are much more light/dark and UV!
They are Triassic superstars. Just amazing critters. So jealous for the Yankees that can see them along the seashore during mating season.
I stupidly didn’t take a good picture the year I saw so many they looked like the beach was cobblestoned, but the eggs are SUPER cool. The whole sand changes color, there’s so many.
Evolutionary arms race? Never heard of it. I‘m perfect. 💅 - Horseshoe crabs, if they could speak (probably)