Yoshida Kohta, Herrmann Matthias, Kanzaki Natsumi, Weiler Christian, Rödelsperger Christian, Sommer Ralf J
Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, Spemannstraße 37, Tübingen, Germany.
Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto 612-0855, Japan.
J Nematol. 2018;50(3):355-368. doi: 10.21307/jofnem-2018-019.
Pristionchus pacificus Sommer, Carta, Kim, and Sternberg, 1996 is an important model organism in evolutionary biology that aims to integrate developmental biology and evo-devo with population genetics and ecology. Functional studies in P. pacificus are supported by a well-established phylogenetic framework of around 30 species of the genus Pristionchus that have been described in the last decade based on their entomophilic and necromenic association with scarab beetles. Biogeographically, East Asia has emerged as a hotspot of Pristionchus speciation and recent samplings have therefore focused on Islands and mainland settings in East Asia. Here, we describe in a series of three publications the results of our sampling efforts in Taiwan, Japan, and Hongkong in 2016 and 2017. We describe a total of nine new species that cover different phylogenetic species-complexes of the Pristionchus genus. In this first publication, we describe two new species, Pristionchus sikae sp. n. and Pristionchus kurosawai sp. n. that are closely related to P. pacificus . Together with five previously described species they form the " pacificus species-complex sensu stricto" that is characterized by all species forming viable, but sterile F1 hybrids indicating reproductive isolation. P. sikae sp. n. and P. kurosawai sp. n. have a gonochorist mode of reproduction and they are described using morphology, morphometrics, mating experiments, and genome-wide sequence analysis. We discuss the extreme diversification in the pacificus species-complex sensu stricto in East Asia and its potential power to study speciation processes.
太平洋小杆线虫（Pristionchus pacificus Sommer、Carta、Kim和Sternberg，1996）是进化生物学中的一种重要模式生物，旨在将发育生物学和进化发育生物学与群体遗传学和生态学相结合。对太平洋小杆线虫的功能研究得到了一个完善的系统发育框架的支持，该框架包含了近十年内描述的约30种小杆线虫属物种，这些物种基于它们与金龟子的嗜虫和尸食共生关系被描述。在生物地理学上，东亚已成为小杆线虫物种形成的热点地区，因此最近的采样工作集中在东亚的岛屿和大陆地区。在此，我们在三篇系列出版物中描述了我们在2016年和2017年对台湾、日本和香港进行采样工作的结果。我们总共描述了九个新物种，它们涵盖了小杆线虫属不同的系统发育物种复合体。在这第一篇出版物中，我们描述了两个新物种，即梅花鹿小杆线虫（Pristionchus sikae sp. n.）和黑泽小杆线虫（Pristionchus kurosawai sp. n.），它们与太平洋小杆线虫密切相关。它们与五个先前描述的物种一起形成了“狭义太平洋小杆线虫物种复合体”，其特征是所有物种都能形成可存活但不育的F1杂种，表明存在生殖隔离。梅花鹿小杆线虫和黑泽小杆线虫具有雌雄异体的繁殖方式，我们通过形态学、形态测量学、交配实验和全基因组序列分析对它们进行了描述。我们讨论了东亚狭义太平洋小杆线虫物种复合体中的极端多样化及其在研究物种形成过程中的潜在作用。
