Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553-1675, USA.
Proc Biol Sci. 2023 Aug 9;290(2004):20230851. doi: 10.1098/rspb.2023.0851. Epub 2023 Aug 2.
Sampling in multiple localities, coupled with molecular barcoding, has shown that nominal species with wide geographical distribution often harbour local cryptic species in allopatry. Cryptic species in sympatry, however, can be easily missed if they have different seasonality, because they can be identified only through long-term frequent sampling (i.e. sampling through time of the same species in the same location). This is especially true in planktonic invertebrates that exhibit strong seasonality. By integrating mitochondrial 16S sequences of eight species of Hydrozoa (Cnidaria) collected weekly for a year in one Gulf of Mexico region, with sequences gathered globally, we investigate the presence of cryptic species within a temporal gradient (regionally) and on a spatial (worldwide) scale. We find that eight species of Hydrozoa are composed of 28 cryptic species, with 16 of them appearing in sympatry but with non-overlapping seasonality. The high number of sympatric cryptic species could only be discovered through extensive and prolonged regional sampling efforts. The bi-dimensional cryptic diversity (in time and space) highlighted in this study is essential for understanding processes of evolution, biogeography dispersal in the sea, and for more realistic biodiversity assessments.
在多个地点进行采样，并结合分子条形码技术，表明具有广泛地理分布的名义物种通常在异域地区拥有当地的隐种。然而，如果隐种具有不同的季节性，那么在同域中就很容易被忽视，因为只有通过长期频繁的采样（即在同一地点对同一物种进行时间采样）才能识别它们。对于表现出强烈季节性的浮游无脊椎动物来说尤其如此。通过整合在墨西哥湾一个地区每周采集一年的 8 种水螅（刺胞动物）的线粒体 16S 序列，以及在全球范围内收集的序列，我们研究了在时间梯度（区域）和空间（全球）尺度上隐种的存在情况。我们发现，8 种水螅由 28 种隐种组成，其中 16 种出现在同域，但季节性不重叠。只有通过广泛而长期的区域采样努力，才能发现大量的同域隐种。本研究中强调的二维隐种多样性（时间和空间）对于理解进化过程、海洋生物地理扩散以及更现实的生物多样性评估至关重要。
