What is "jaekelopterus"

Jaekelopterus (" Otto Jaekel's wing) is an extinct genus of sea scorpion. Jaekelopterus lived approximately 390 million years ago. At an estimated length of , it is the largest known arthropod ever discovered, surpassing the Pterygotus and even the millipede-like Arthropleura. There are two species, one being the type species, J. rhenaniae, from freshwater strata in the Rhineland, and J. howelli from estuarine strata in Wyoming.