Meganeura, meaning "Large-Nerved," is a prehistoric griffinfly named after the veins in its giant wings. Griffinflies are similar to dragonflies, but lack a feature of dragonfly wings. Meganeura was one of the largest griffinflies, with a wingspan of 70 centimeters! There are several hypotheses about why these insects got to be so huge, but none are completely sufficient explanations. The most popular states that higher oxygen levels allowed them to grow larger, and while there is some evidence to support this, the fact that species of giant flying insects exist in later, less oxygenated time periods casts some doubt on this explanation. Another hypothesis refers to a lack of predators to eat them, letting them grow to maximum size and eat larger prey. Meganeura lived in the Late Carboniferous Period alongside its fellow giant arthropod Arthropleura in an environment called the coal forest. The coal forest was a rainforest-like wetland that later became the coal we burn today (hence the name). These forests supported a diverse ecosystem that ranged from invertebrates like Meganeura to ancient amphibians and reptiles. Meganeura thrived in this environment, feasting on other insects like the flying herbivores of the order Palaeodictyoptera.