Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA.
SNSB-Bavarian State Collection of Zoology, Münchhausenstrasse 21, 81247, Munich, Germany.
Sci Rep. 2021 Apr 19;11(1):8473. doi: 10.1038/s41598-021-87244-5.
Sampling impediments and paucity of suitable material for molecular analyses have precluded the study of speciation and radiation of deep-sea species in Antarctica. We analyzed barcodes together with genome-wide single nucleotide polymorphisms obtained from double digestion restriction site-associated DNA sequencing (ddRADseq) for species in the family Antarctophilinidae. We also reevaluated the fossil record associated with this taxon to provide further insights into the origin of the group. Novel approaches to identify distinctive genetic lineages, including unsupervised machine learning variational autoencoder plots, were used to establish species hypothesis frameworks. In this sense, three undescribed species and a complex of cryptic species were identified, suggesting allopatric speciation connected to geographic or bathymetric isolation. We further observed that the shallow waters around the Scotia Arc and on the continental shelf in the Weddell Sea present high endemism and diversity. In contrast, likely due to the glacial pressure during the Cenozoic, a deep-sea group with fewer species emerged expanding over great areas in the South-Atlantic Antarctic Ridge. Our study agrees on how diachronic paleoclimatic and current environmental factors shaped Antarctic communities both at the shallow and deep-sea levels, promoting Antarctica as the center of origin for numerous taxa such as gastropod mollusks.
采样障碍以及缺乏适合分子分析的材料，使得对南极洲深海物种的物种形成和辐射研究受到阻碍。我们分析了条形码以及从双酶切限制位点相关 DNA 测序 (ddRADseq) 获得的全基因组单核苷酸多态性，用于研究 Antarctophilinidae 科的物种。我们还重新评估了与该分类群相关的化石记录，以进一步了解该组的起源。我们还采用了新颖的方法来识别独特的遗传谱系，包括无监督机器学习变分自动编码器图，以建立物种假设框架。在这种意义上，确定了三个未描述的物种和一个隐种复合体，表明与地理或水深隔离有关的异域物种形成。我们进一步观察到，斯科舍弧形周围的浅水区和威德尔海大陆架上的浅水区具有高特有性和多样性。相比之下，可能由于新生代的冰川压力，一个具有较少物种的深海群落在南大西洋南极脊上的广大地区扩张。我们的研究表明，时变古气候和当前环境因素如何塑造了浅海和深海层面的南极生物群落，使南极洲成为许多类群（如腹足纲软体动物）的起源中心。
