Data from: Angelfishes, paper tigers and the devilish taxonomy of the Centropyge flavissima complex

The pygmy angelfishes (genus Centropyge) provide numerous examples of discordance between color morphology, taxonomy and evolutionary genetic lineages. This discordance is especially evident in the Centropyge flavissima complex, which includes three primary color morphs, three previously recognized species (C. flavissima, C. eibli and C. vrolikii) and three distinct mitochondrial (mtDNA) lineages that do not align with species designations. Our previous research showed that the putative C. flavissima arose independently in the Indian and Pacific Oceans, and the three mtDNA lineages align with geography rather than species assignments. Here we add 157 specimens to the previous dataset of 291 specimens, spread across a greater geographic range, to pinpoint the distribution of mtDNA lineages and color morphs. We found that the mtDNA lineages show remarkably strong geographic boundaries corresponding to the Indian Ocean, Central-West Pacific and Central-South Pacific. We also test the validity of the ‘Black Tiger Centropyge’ in the C. flavissima species complex, a taxonomic oddity that is restricted to shoals and atolls off the coast of northwestern Australia, and the newly named C. cocosensis (Shen et al. sp. nov. 2016) assigned to the C. flavissima lineage in the Indian Ocean. We conclude that the Black Tiger Centropyge is not a valid species but an intermediate between sympatric color morphs that correspond to the putative species C. eibli and C. vrolikii. Our greater sampling effort also do not support the genetic distinctiveness of C. cocosensis given shared mtDNA haplotypes with the sympatric C. eibli and C. vrolikii, but instead we find conflicting lines of evidence concerning the taxonomy of this group. We urge caution and taxonomic restraint until the true nature of this species complex can be revealed.

侏儒刺尻鱼属（Centropyge）的物种存在大量色彩形态、分类学与演化遗传支系之间不一致的实例。这种不一致在黄刺尻鱼复合群（Centropyge flavissima complex）中尤为显著：该复合群包含3种主要色彩形态、3个此前被认可的物种（C. flavissima、C. eibli与C. vrolikii），以及3个与物种命名不符的独立线粒体DNA（mtDNA）支系。我们此前的研究表明，被推定的C. flavissima分别在印度洋与太平洋独立起源，且3个线粒体支系的分布与地理区域相关，而非物种命名。本研究在原有291份标本的数据集基础上新增157份标本，采样覆盖更广的地理范围，以精准确定线粒体支系与色彩形态的分布区域。研究发现，线粒体支系呈现出极为清晰的地理分界，分别对应印度洋、中西太平洋以及中南太平洋区域。本研究同时验证了黄刺尻鱼复合群中“黑虎刺尻鱼（Black Tiger Centropyge）”的分类有效性——该类群为分类学上的特殊类群，仅分布于澳大利亚西北近海的沙洲与环礁区域；此外还对2016年由Shen等人发表的新种C. cocosensis（Shen et al. sp. nov. 2016）进行了检验，该新种曾被归入印度洋的黄刺尻鱼支系。本研究认定，黑虎刺尻鱼并非有效物种，而是对应于被推定物种C. eibli与C. vrolikii的同域色彩形态之间的过渡类群。本次扩大的采样范围并未发现C. cocosensis具有遗传独特性：该类群与同域分布的C. eibli和C. vrolikii共享线粒体DNA单倍型（mtDNA haplotypes），本研究同时得到了与该类群分类学相关的相互矛盾的证据。本研究呼吁在该物种复合群的本质被阐明之前，应保持分类学研究的谨慎与克制。