The presence of eagle rays of the genus Aetomylaeus in the Neogene of the Temperate Pacific coast of South America (TPSA) still is ambiguous, although the fossil record of elasmobranch fishes (sharks, rays, and skates) from this area is quite good. Here, we present the first unmistakable fossil remains of Aetomylaeus from the Neogene of the TPSA. The material comprises 13 dental plates from one site in Peru and six localities in Chile ranging in age from Miocene to Pliocene and was compared with dental plates of extant species. Our study reveals that the number of tooth rows and the shape of lateral teeth in extant species are seemingly very variable and need to be established before fossil specimens can be confidently identified. Consequently, we do not assign the fossil specimens from the Neogene of the TPSA to any species but leave them as Aetomylaeus. Moreover, we recognized that only the shape of medial teeth provides reliable diagnostic characters in our material, whereas the shape and number of lateral teeth are highly variable, similar to the condition seen in extant species.

南美温带太平洋海岸地区的新近纪（TPSA）的新近存在埃特穆属（Aetomylaeus）鹰射线，尽管该地区的浮游鱼类（鲨鱼，rays鱼和滑冰）的化石记录相当好，但仍然模糊不清。在这里，我们介绍了Aetomylaeus的第一个无误的化石遗迹来自TPSA的Neogene。该材料包括来自秘鲁一个地点和智利六个地区的13个牙板，年龄从中新世到上新世，并与现存物种的牙板进行了比较。我们的研究表明，现存物种中的齿排数和侧齿的形状看似非常多变，需要确定之前才能确定化石标本。因此，我们不会将TPSA的新近纪的化石标本分配给任何物种，而将其保留为拟杆菌属。此外，我们认识到，只有内侧牙齿的形状才能在我们的材料中提供可靠的诊断特征，而外侧牙齿的形状和数量却高度可变，类似于现存物种中的情况。