The Apaporis caiman (Caiman crocodilus apaporiensis) has been of particular interest due to its highly differentiated morphology. However, no molecular research has been done to clarify its taxonomy. We characterized the genetic variation within C. crocodilus by assessing the evolutionary trajectory of Apaporis caiman populations using mitochondrial molecular markers. We collected ten Apaporis caiman samples from the middle basin of the Apaporis River, Colombia, sequenced two mitochondrial genes [cytochrome oxidase I (COI) and cytochrome B (CytB)], and analysed them together with all available sequences from homologous gene fragments at GenBank for the species. Phylogenetic reconstructions revealed three main clades clearly differentiated across the C. crocodilus complex. These clades matched genetically and geographically with three of the four subspecies currently recognized (C. c. chiapasius, C. c. fuscus and C. c. crocodilus). However, we found low to almost non-existent genetic differentiation between C. c. crocodilus and the until-now morphologically recognized C. c. apaporiensis, suggesting that the latter is part of the genetic spectrum present within C. c. crocodilus. We reject the hypothesis of an expected elevated level of genetic variation due to isolation (supported by morphological differentiation) and support the idea of Apaporis caiman populations as a C. crocodilus ecomorph.

中文翻译：

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揭开谜底：通过线粒体分子制造商评估Apaporis凯门鳄种群（Caiman crocodilus apaporiensis，Medem 1955）的进化轨迹

Apaporis caiman（Caiman crocodilus apaporiensis）由于其高度分化的形态而引起了特别的兴趣。但是，尚未进行分子研究来阐明其分类学。通过使用线粒体分子标记评估Apaporis凯门鳄种群的进化轨迹，我们表征了C. crocodilus内的遗传变异。我们从哥伦比亚Apaporis河中部盆地收集了十个Apaporis凯门鳄样本，对两个线粒体基因[细胞色素氧化酶I（COI）和细胞色素B（CytB））]，并与GenBank中该物种同源基因片段的所有可用序列一起对它们进行了分析。系统发育重建揭示了三个主要进化枝，在整个C. crocodilus复合物中明显区分开。这些进化枝遗传上和地理上匹配有三个当前识别的四个亚种的（C.℃。chiapasius，C.角鲇和C.℃。鳄）。但是，我们发现C. c。之间的遗传分化程度很低甚至几乎不存在。鳄和迄今为止在形态学上公认的C．apaporiensis，表明后者是存在于C. c。中的遗传谱的一部分。鳄。我们拒绝由于隔离（由形态分化支持）而导致的预期遗传变异水平升高的假设，并支持Apaporis凯门鳄种群作为C. crocodilus ecomorph的想法。