Duda Thomas F, Kohn Alan J, Matheny Amber M
Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, 1109 Geddes Avenue, Ann Arbor, Michigan 48109, USA.
Biol Bull. 2009 Dec;217(3):292-305. doi: 10.1086/BBLv217n3p292.
Anomalous mitochondrial and nuclear gene sequences in individuals of the widely distributed tropical marine gastropod Conus ebraeus that were not distinguishable by shell shape and color pattern characters suggested the presence of a second, cryptic species. We tested this hypothesis by genetic, morphological, and ecological comparisons of additional individuals from the site in Okinawa where the two forms co-occurred. Radular tooth size and shape, prey type in nature, and microhabitats utilized differed markedly between the two forms. Adults with typical C. ebraeus DNA and radular teeth preyed primarily on errant polychaetes (Eunicidae); those with anomalous DNA and teeth ate mainly sedentary capitellids. Juveniles (shell length <13 mm) had more similar teeth and ate primarily syllids. Radular teeth of the anomalous form agreed with those of Conus judaeus, distinguished from C. ebraeus by Rudolph Bergh in 1895 solely on tooth characters of one specimen from the Philippines. Samples from other widely scattered Pacific localities revealed only typical C. ebraeus gene sequences. Both forms occurred in Seychelles (western Indian Ocean), where their radular teeth and diets were consistent with the data from Okinawa, but DNA of available material was degraded. Although C. judaeus was long dismissed as an aberrant specimen and junior synonym of C. ebraeus, our results support its validity as a distinct species. These results highlight the importance of molecular and radular tooth characters relative to those of the shell. Moreover, cryptic species could well be important components of species richness in Conus specifically and marine molluscan biodiversity more generally.
广泛分布的热带海洋腹足纲动物白纹芋螺个体中，线粒体和核基因序列异常，这些个体在壳形和颜色图案特征上无法区分，这表明存在第二个隐性物种。我们通过对来自冲绳该地点的其他个体进行遗传、形态和生态比较，检验了这一假设，在该地点两种形态共存。两种形态在齿舌齿的大小和形状、自然猎物类型以及所利用的微生境方面存在显著差异。具有典型白纹芋螺DNA和齿舌齿的成年个体主要捕食游走多毛类动物（矶沙蚕科）；具有异常DNA和齿舌齿的个体主要捕食定居的小头虫科动物。幼体（壳长<13毫米）的齿舌齿更相似，主要捕食裂虫类动物。异常形态的齿舌齿与朱迪芋螺的齿舌齿一致，1895年鲁道夫·伯格仅根据来自菲律宾的一个标本的齿舌特征将其与白纹芋螺区分开来。来自其他广泛分布的太平洋地区的样本仅显示典型的白纹芋螺基因序列。两种形态都出现在塞舌尔（印度洋西部），它们的齿舌齿和食性与来自冲绳的数据一致，但现有材料的DNA已降解。尽管朱迪芋螺长期以来被视为异常标本和白纹芋螺的次异名，但我们的结果支持其作为一个独特物种的有效性。这些结果突出了分子和齿舌齿特征相对于壳特征的重要性。此外，隐性物种很可能是芋螺属物种丰富度的重要组成部分，更广泛地说，也是海洋软体动物生物多样性的重要组成部分。
