Doctorado en Ciencias, Mención Ecología y Evolución, Universidad Austral de Chile, Campus Isla Teja s/n, Valdivia 5090000, Chile; Instituto de Paleontología, Universidad Nacional de Piura, Piura 20002, Peru.
Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja s/n, Valdivia 5090000, Chile.
Mol Phylogenet Evol. 2021 Jun;159:107111. doi: 10.1016/j.ympev.2021.107111. Epub 2021 Feb 16.
As currently understood, the genus Octodon contains five species degus, lunatus, bridgesii, pacificus, and ricardojeda. Previous phylogenetic studies suggest that genus specific diversity is underestimated. In order to evaluate the taxonomic diversity of Octodon, we implemented unilocus (cytochrome-b) and multilocus (cytochrome-b + 4 nuclear genes) species delimitation methods. Octodon degus was recovered as a sister of the other species of the genus. The unilocus bGMYC and mPTP methods, based on cytochrome-b sequences, delimits 11 and 7 candidate species respectively, and both methods fail to recognize O. pacificus from O. ricardojeda. Results of the multilocus analysis (BPP) vary as a function of the dataset used. When the five genes are used 11 species are delimited, while eight species are delimited when only the nuclear genes are used. Octodon bridgesii is shown as comprising at least two species (one on the Pacific coast and the typical form found on the Andean slopes), while O. ricardojeda may comprise two species (one on the Chilean side of the Andes and the other in Argentina). Likewise, both multilocus matrices recover O. pacificus as a distinct species. This shows that species diversity of Octodon is underestimated. Remarkably, many of the delimited species based on genetic data are morphologically differentiated in cranio-dental characteristics. However, a pair of species has not achieved morphological differentiation, being cryptic species. Finally, the incongruence between mitochondrial and nuclear phylogenies suggests that processes such as incomplete lineage sorting and/or introgression have been present during the radiation of the genus.
目前已知的毛丝鼠属包含五种，分别是毛丝鼠、白足毛丝鼠、秘鲁毛丝鼠、短尾毛丝鼠和智利毛丝鼠。先前的系统发育研究表明，该属的种特异性多样性被低估了。为了评估毛丝鼠的分类多样性，我们实施了单基因座（细胞色素-b）和多基因座（细胞色素-b+4 核基因）物种界定方法。毛丝鼠被恢复为该属其他物种的姐妹种。基于细胞色素-b 序列的单基因座 bGMYC 和 mPTP 方法分别界定了 11 种和 7 种候选种，这两种方法都无法识别 O. pacificus 和 O. ricardojeda。多基因座分析（BPP）的结果因数据集的使用而异。当使用五个基因时，界定了 11 个种，而仅使用核基因时，界定了 8 个种。毛丝鼠 bridgesii 至少包含两个种（一个在太平洋海岸，另一个在安第斯山脉的典型形式），而 O. ricardojeda 可能包含两个种（一个在安第斯山脉智利一侧，另一个在阿根廷）。同样，多基因座矩阵都将 O. pacificus 恢复为一个独特的物种。这表明毛丝鼠的物种多样性被低估了。值得注意的是，许多基于遗传数据界定的种在颅齿特征上存在形态分化。然而，有一对种尚未实现形态分化，是隐种。最后，线粒体和核系统发育之间的不匹配表明，在该属的辐射过程中，存在不完全谱系分选和/或基因渗入等过程。
