The pelagic snail Limacina helicina Phipps, 1774 is widely distributed in high-latitude seas and is a sensitive bioindicator of ocean acidification. It is known that the response patterns to ocean acidification differ among populations within or among species. Thus, it is important to understand their genetic population structure and identify the cryptic species. L. helicina displays different shell morphotypes, called “formae,” in different regions (North Atlantic, L. helicina forma helicina Phipps, 1774; Northwest Pacific, L. helicina f. acuta Spoel, 1967; Northeast Pacific, L. helicina f. pacifica Dall, 1871; Okhotsk Sea, L. helicina f. ochotensis Shkoldina, 1999: Spoel, 1967, pp. 257, 349). A recent study by Shimizu et al. (Journal of Molluscan Studies 84:30-37, 2018) showed clear genetic differentiation between two formae, L. helicina forma helicina (Svalbard in the Arctic Ocean) and L. helicina f. acuta (station K2 in the western North Pacific) (ΦCT = 0.59282), using partial mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. However, whether other formae of this species are genetically distinct remain unknown. Here we focused on L. helicina f. ochotensis, which inhabits the Sea of Okhotsk, and compared its shell morphology and partial mitochondrial COI gene sequences with another forma, L. helicina f. acuta, which is found in the western North Pacific. We found differences in the shell morphology of L. helicina f. ochotensis collected from the Sea of Okhotsk (off the coast of Monbetsu, Hokkaido, Japan) and L. helicina f. acuta collected from the western North Pacific (station K2). However, molecular analysis of an mtDNA COI region (503 bp) revealed that most individuals collected from Monbetsu (Sea of Okhotsk) were haplotype 1 (75.5%), which is also the major haplotype found in L. helicina f. acuta (western North Pacific). Our results suggest that individuals of L. helicina are frequently dispersed between the Sea of Okhotsk and the western North Pacific by ocean currents. Thus, the two formae, L. helicina f. acuta and L. helicina f. ochotensis, are more likely to be attributable to phenotypic plasticity in response to different environmental parameters, such as temperature and salinity, than to differences in their genetic backgrounds.

远洋蜗牛Limacina helicina Phipps，1774年在高纬度海域广泛分布，是海洋酸化的敏感生物指示剂。众所周知，物种内部或物种之间对海洋酸化的响应方式不同。因此，重要的是了解它们的遗传种群结构并鉴定隐性物种。L. helicina显示不同的壳形态，所谓不同地区（北大西洋，“formae，” L. helicina备考helicina菲普斯，1774;西北太平洋，属helicina F。蚧Spoel，1967年，东北地区，L. helicina F。太平洋Dall，1871年；鄂霍次克海，Helicina f。ochotensis Shkoldina，1999：Spoel，1967，第257、349页）。Shimizu等人的最新研究。（软体动物研究杂志84：30-37，2018）显示了两种形式的明确的遗传分化，即L. helicina forma helicina（北冰洋上的斯瓦尔巴特群岛）和L. helicina f 。acuta（北太平洋西部的K2站）（ΦCT= 0.59282），使用部分线粒体细胞色素C氧化酶亚基I（COI）基因序列。但是，该物种的其他形态是否在遗传上仍不清楚。在这里，我们集中于L. helicina f。ot草，位于鄂霍次克海，并将其壳形态和线粒体部分COI基因序列与另一种形式L. helicina f进行了比较。acuta，位于北太平洋西部。我们发现L. helicina f的壳形态存在差异。ochotensis收集从鄂霍次克海（关纹别，日本北海道沿岸）和L. helicina ˚F 。从北太平洋西部（K2站）收集的金丝鱼。然而，对mtDNA COI区域（503 bp）的分子分析表明，从Monbetsu（鄂霍次克海）收集的大多数个体为单倍型1（75.5％），这也是在L. helicina f中发现的主要单倍型。。阿库塔（北太平洋西部）。我们的结果表明，螺旋藻的个体经常被洋流分散在鄂霍次克海和北太平洋西部之间。因此，这两个formae helicina f 。acuta和L. helicina f 。ochotensis更可能归因于对不同环境参数（例如温度和盐度）的响应而产生的表型可塑性，而不是其遗传背景的差异。