Department of Ecology and Evolutionary Biology, University of Michigan, 1105 N. University, 48109 Ann Arbor, MI, USA.
Laboratório de Ictiologia, Departamento de Zoologia, Universidade Federal do Rio Grande do Sul. Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil; Department of Ichthyology, The Academy of Natural Sciences of Drexel University, 1900 Benjamin Franklin Parkway, 19103 Philadelphia, PA, USA.
Mol Phylogenet Evol. 2019 Mar;132:265-274. doi: 10.1016/j.ympev.2018.12.008. Epub 2018 Dec 7.
With 22 described species, Phalloceros is the most species-rich genus of Poeciliidae in South America. Phalloceros diversity is characterized by high degrees of endemism and sympatry in coastal and inland drainages in southeastern South America. The taxa are also characterized by pronounced differentiation in sexual characters (i.e., female urogenital papilla and male gonopodium), which might have contributed to their diversification. Here we estimate phylogenetic relationships based on more than 18,000 loci in 93 individuals representing 19 described species and two putative undescribed species. Morphologically defined species correspond to monophyletic species lineages, with individuals within a species clustering together in phylogenetic estimates, with the main exception being P. harpagos, supporting undiscovered diversity in this morphospecies. Shifts in the female and male sexual traits (i.e., urogenital papilla and gonopodium) occurred in concert multiple times along the phylogeny highlighting the role of sexual selection in driving divergence in this genus. Out of 22 valid species, 14 species are found in sympatry with at least one other species of this genus. However, most co-occurrences are observed among non-sister species suggesting that diversification among closely related species involved mostly allopatric speciation, with only two instances of sympatric sister-species observed. A strong mismatch in sexual traits among sympatric taxa suggests that co-existence may be linked to divergent sexual traits that maintain species genetic distinctiveness through mechanical disruptions of interbreeding.
拥有 22 个描述物种，Phalloceros 是南美洲中 Poeciliidae 科中物种最丰富的属。Phalloceros 的多样性特征是东南南美洲沿海和内陆流域具有高度的特有性和同域性。这些分类群还具有明显的性特征分化（即雌性泌尿生殖乳头和雄性交接器），这可能促成了它们的多样化。在这里，我们根据 93 个个体的超过 18000 个基因座来估计系统发育关系，这些个体代表了 19 个描述物种和两个假定的未描述物种。形态定义的物种对应于单系物种谱系，同一物种内的个体在系统发育估计中聚集在一起，主要例外是 P. harpagos，支持该形态物种中未发现的多样性。雌性和雄性性特征（即泌尿生殖乳头和交接器）的变化多次沿着系统发育同时发生，突出了性选择在推动该属物种分化中的作用。在 22 个有效物种中，有 14 个物种与该属的至少另一个物种共存。然而，大多数共存现象发生在非姐妹种之间，这表明密切相关物种之间的多样化主要涉及异域物种形成，仅观察到两个同域姐妹种共存的实例。在同域分类群中，性特征的强烈不匹配表明共存可能与不同的性特征有关，这些特征通过机械干扰杂交来维持物种的遗传独特性。
