Furthermore, the supposed genus could well be paraphyletic, so that for example "Dyspetornis" – which is now contained therein – might have to be separated again. A leg of an undescribed small loon was found in the Late Oligocene deposits at Enspel (Germany); it too may or may not belong to "Colymboides". Of the crown genus "Gavia", nearly ten prehistoric species have been named to date, and about as many undescribed ones await further study. The genus is known from the Early Miocene onwards, and the oldest members them are rather small (some are smaller than the red-throated loon). Throughout the late Neogene, the genus by and large follows Cope's Rule.