Sources : Ludolacra

Aristotle [ca. 350 BCE] (De animalibus, Book 1, chapter 5.2): And among apodous swimming animals some have fins, as fish; and of these some have two fins in the upper and two in the lower part of their bodies, as the chrysophys and labrax... - [Cresswell translation, 1887]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Marine monsters 6.32): Ludolacra is marine animal that is very wonderful in nature and form, as Aristotle says. It has four wings arranged in this way: it has two on its face and two on its back, with which it moves with wonderful speed from place to place, wherever its will impels it. - [Badke translation/paraphrase]