The concept of DNA barcoding, which   applies the mitochondrial cytochrome c oxidase subunit 1 (COI) marker in   animals, is based on the premise that there is low variation within species   and large divergence gaps between sister species (Hebert et al. 2003, 2004b).   Accordingly, provisional species are often suggested when sequence divergence   exceeds a certain threshold (e.g., 10 times average intraspecific variation;   Carr et al. 2011; Kerr et al. 2007). However, there are examples of sympatric   intraspecific divergences of a magnitude that exceeds normal sister species‐level divergence (Wayne et al. 1990; Tominaga et al. 2009; Xiao et   al. 2012), making species discrimination based on a strict divergence   threshold in mtDNA too simplistic (Moritz and Cicero 2004).

将线粒体细胞色素c氧化酶亚基1（COI）标记应用于动物的DNA条形码的概念是基于物种种内变异小、姊妹物种间差异大的前提（Hebert et al. 2003, 2004b）。因此，当序列差异超过某一阈值（例如，10倍的平均种内差异；Carr et al. 2011; Kerr et al. 2007）时，通常建议使用临时物种。然而，也有一些同一地区种内差异差异超过姊妹种种间差异的例子，（Wayne et al. 1990; Tominaga et al. 2009; Xiao et al. 2012），这样，基于严格的线粒体DNA分歧阈值进行物种界定的方法就显得过于简单化（Moritz and Cicero 2004）。