National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo, 190-8518, Japan.
Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, 9 Asamushi, Aomori, 039-3501, Japan.
Sci Rep. 2021 Jan 15;11(1):1557. doi: 10.1038/s41598-020-80702-6.
The phylum Annelida exhibits high morphological diversity coupled with its extensive ecological diversity, and the process of its evolution has been an attractive research subject for many researchers. Its representatives are also extensively studied in fields of ecology and developmental biology and important in many other biology related disciplines. The study of biomineralisation is one of them. Some annelid groups are well known to form calcified tubes but other forms of biomineralisation are also known. Herein, we report a new interstitial annelid species with black spicules, Thoracophelia minuta sp. nov., from Yoichi, Hokkaido, Japan. Spicules are minute calcium carbonate inclusions found across the body and in this new species, numerous black rod-like inclusions of calcium-rich composition are distributed in the coelomic cavity. The new species can be distinguished from other known species of the genus by these conspicuous spicules, shape of branchiae and body formula. Further, the new species' body size is apparently smaller than its congeners. Based on our molecular phylogenetic analysis using 18S and 28S sequences, we discuss the evolutionary significance of the new species' spicules and also the species' progenetic origin.
环节动物门表现出高度的形态多样性，加上其广泛的生态多样性，其进化过程一直是许多研究人员感兴趣的研究课题。它的代表在生态学和发育生物学领域也得到了广泛的研究，在许多其他与生物学相关的学科中也很重要。生物矿化研究就是其中之一。一些环节动物群以形成钙化管而闻名，但也存在其他形式的生物矿化。本文报道了一种来自日本北海道余市的新的间生环节动物物种，Thoracophelia minuta sp. nov.。小刺是在整个身体中发现的微小碳酸钙内含物，在这个新物种中，大量富钙的黑色杆状内含物分布在体腔中。新种可以通过这些明显的小刺、鳃的形状和身体公式与其他已知的种相区别。此外，新种的体型明显小于其同属种。基于我们使用 18S 和 28S 序列进行的分子系统发育分析，我们讨论了新种小刺的进化意义以及该种的祖源。
