Brooks D R
Department of Zoology, University of Toronto, Ontario, Canada.
J Parasitol. 1992 Aug;78(4):588-95.
Members of the freshwater stingray family Potamotrygonidae occur throughout the major river systems of eastern South America that empty into the Atlantic Ocean. Ichthyologists have tended to assume that the ancestor of the potamotrygonids was an Atlantic marine or euryhaline stingray that dispersed into freshwater, presumably during the last marine ingression 3-5 million years ago. The helminth parasites that inhabit potamotrygonids suggest an alternative perspective on their origin. Phylogenetic and biogeographic analysis of the helminths inhabiting potamotrygonids suggest that the hosts are derived from an ancestral Pacific urolophid stingray that was trapped in freshwater by the uplifting of the Andes beginning perhaps as early as the early Cretaceous period and ending by the mid-Miocene epoch, changing the course of the Amazon River, which previously had flowed into the Pacific Ocean.
淡水魟科（Potamotrygonidae）的成员分布在南美洲东部流入大西洋的主要河流系统中。鱼类学家倾向于认为，淡水魟科的祖先为大西洋海洋或广盐性魟，大概在300万至500万年前的最后一次海侵期间扩散到淡水中。栖息在淡水魟科鱼类身上的蠕虫寄生虫为它们的起源提供了另一种观点。对栖息在淡水魟科鱼类身上的蠕虫进行的系统发育和生物地理学分析表明，这些宿主源自太平洋原魟科的一种祖先魟，这种魟可能早在白垩纪早期就因安第斯山脉的隆起而被困在淡水中，一直持续到中新世中期，改变了此前流入太平洋的亚马逊河的河道。
