Alarcón-Elbal Pedro María, García-Jiménez Ricardo, Peláez María Luisa, Horreo Jose Luis, Valdecasas Antonio G
Instituto de Medicina Tropical & Salud Global (IMTSAG), Universidad Iberoamericana (UNIBE), Santo Domingo 22333, Dominican Republic.
Museo Nacional de Ciencias Naturales, CSIC. C/José Gutiérrez Abascal, 2, 28006 Madrid, Spain.
Life (Basel). 2020 Jul 9;10(7):108. doi: 10.3390/life10070108.
The systematics of many groups of organisms has been based on the adult stage. Morphological transformations that occur during development from the embryonic to the adult stage make it difficult (or impossible) to identify a juvenile (larval) stage in some species. Hydrachnidia (Acari, Actinotrichida, which inhabit mainly continental waters) are characterized by three main active stages-larval, deutonymph and adult-with intermediate dormant stages. Deutonymphs and adults may be identified through diagnostic morphological characters. Larvae that have not been tracked directly from a gravid female are difficult to identify to the species level. In this work, we compared the morphology of five water mite larvae and obtained the molecular sequences of that found on a pupa of the common mosquito () with the sequences of 51 adults diagnosed as species and identified the undescribed larvae as . Further corroborating this finding, adult was found thriving in the same mosquito habitat. We established the identity of adult and deutonymph by morphology and by correlating COI and cytB sequences of the water mites at the larval, deutonymph and adult (both male and female) life stages in a particular case of 'reverse taxonomy'. In addition, we constructed the Arrenuridae phylogeny based on mitochondrial DNA, which supports the idea that three Arrenurus subgenera are 'natural': Arrenurus, Megaluracarus and Micruracarus, and the somewhat arbitrary distinction of the species assigned to the subgenus Truncaturus.
许多生物类群的分类学是基于成体阶段的。从胚胎期到成体阶段发育过程中发生的形态转变使得在某些物种中识别幼体（幼虫）阶段变得困难（或不可能）。水螨目（蜱螨亚纲，辐螨亚目，主要栖息于陆域水域）的特点是有三个主要活跃阶段——幼体、若螨和成体——以及中间的休眠阶段。若螨和成体可以通过诊断性形态特征来识别。未直接从孕雌体追踪而来的幼虫很难鉴定到物种水平。在这项研究中，我们比较了五种水螨幼虫的形态，并获得了在普通蚊子（ ）蛹上发现的水螨幼虫的分子序列，将其与51只被诊断为 物种的成体序列进行比较，并将未描述的幼虫鉴定为 。进一步证实这一发现的是，在相同的蚊子栖息地发现了成体 在茁壮成长。在一个“反向分类学”的特定案例中，我们通过形态学以及关联水螨在幼虫、若螨和成体（雄性和雌性）生命阶段的细胞色素氧化酶亚基I（COI）和细胞色素b（cytB）序列，确定了成体和若螨 的身份。此外，我们基于线粒体DNA构建了水螨科系统发育树，这支持了三个水螨亚属是“自然的”这一观点：水螨亚属、巨尾水螨亚属和微尾水螨亚属，以及归入截尾水螨亚属的物种划分有些随意。
