👉 Gasterosteiformes are a group of extinct arthropod phyla that lived during the Mesozoic era, approximately 250 million years ago to about 160 million years ago. They were characterized by a single segmented body with two pairs of legs, four pairs of wings, and a long, slender tail. Gasterosteiformes had a high degree of complexity and diversity in terms of their anatomy, morphology, and life history.
