Science. 1986 Oct 10;234(4773):208-9. doi: 10.1126/science.234.4773.208.
Fossil fishes from the Miocene La Venta fauna of the Magdalena River Valley, Colombia, are identified as Colossoma macropomum (Characidae), a living species from the Orinoco and Amazon basins. The fossils document a long and conservative history for a species that is highly specialized for feeding on streamside plants. The phylogenetically advanced position of Colossoma in the subfamily Serrasalminae implies that six related genera and other higher characid taxa originated well before 15 million years ago. This discovery also corroborates neontological evidence for a vicariance event that contributed species from Miocene Orinoco-Amazon faunas to the original Magdalena region fauna. The fossils suggest a formerly diverse Magdalena fauna that has suffered local extinction, perhaps associated with late Cenozoic tectonism. This new evidence may help explain the depauperate nature of the modern Magdalena River.
哥伦比亚马格达莱纳河谷中新世拉文塔动物群中的鱼类化石被鉴定为巨脂鲤（脂鲤科），这是一种生活在奥里诺科河和亚马逊河流域的现生物种。这些化石记录了一个高度适应于溪流植物觅食的物种的漫长而保守的历史。巨脂鲤在锯脂鲤亚科中的系统发育上的先进地位表明，六个相关属和其他较高的脂鲤分类单元起源于 1500 万年前之前。这一发现也证实了新生物证据，即一个隔离事件导致了来自上新世奥里诺科-亚马逊动物群的物种进入了原始马格达莱纳地区动物群。这些化石表明，曾经多样化的马格达莱纳动物群已经遭受了局部灭绝，这可能与晚新生代构造运动有关。这一新证据可能有助于解释现代马格达莱纳河的贫乏性质。
