DOI: 10.5061/dryad.rr4xgxd7h
title: Liolophura species discrimination with geographical distribution patterns and their divergence and expansion history on the northwestern Pacific coast

description: Please refer to Choi et al. (2021): "Choi, E.H., Yeo, M.Y., Kim,
 G. et al. Liolophura species discrimination
 with geographical distribution patterns and their divergence and expansion
 history on the northwestern Pacific coast. Sci
 Rep 11, 17602 (2021). The chiton Liolophura japonica
 (Lischke, 1873) is widely distributed in intertidal coastal areas of the
 northwestern Pacific. Here we show species discrimination of L. japonica
 into two species and one subspecies based on COI and 16S rRNA; L. koreana,
 sp. nov. was mainly distributed at ca. 33°24'–38°32' N, L.
 japonica at ca. 33°24'–35°53' N, and L. j. sinensis, ssp. nov.
 at ca. 27°02'–28°00' N. These species were morphologically
 distinguishable by black spots on the tegmentum and the shape of spicules
 on the perinotum. In addition, we have discussed their molecular
 divergence times (3.37 mya for L. koreana and L. japonica, around the
 mid Pliocene warm period; 1.84 mya for L. japonica and L. j.
 sinensis), demographic expansion events following the last interglacial
 age, called the Eemian (129–116 kya), and augmentation of COI haplotype
 diversity during the late-middle to late Pleistocene. Their latitudinal
 geographical distribution gradients may be helpful for monitoring the
 migration of marine 38 invertebrates north, fostered by global warming in
 the northwestern Pacific.
description: To examine population genetic structure and the possibility of
 species discrimination of <em>L. japonica</em> on the
 northwestern Pacific coast, we collected a total of 304 <em>L.
 japonica </em>samples from nine sampling localities in the
 intertidal coasts of the Korean Peninsula and Japanese Archipelago). From
 the collected <em>L. japonica</em> samples, we amplified the
 <em>COI</em> barcoding region using PCR, and then sequenced
 the 635-bp PCR products. As a result, a total of 75 <em>COI
 </em>haplotypes of <em>L. japonica</em> were detected
 through the present study. To create a <em>COI</em> haplotype
 dataset including previously reported data, we retrieved 31 <em>COI
 </em>haplotypes of <em>L. japonica</em> (also known as
 Acanthopleura japonica) from the NCBI GenBank database, consisting of two
 Japanese and 29 Chinese <em>COI</em> haplotypes. Finally, we
 gathered 106 <em>CO</em>I haplotypes from 431<em> L.
 japonica</em> individuals in twelve localities of South Korea,
 Japan, and southern China. In the case of <em>16S
 rRNA</em> genes, the 304 samples of <em>L. japonica</em>
 from nine localities in the intertidal coasts on the Korean Peninsula and
 Japanese Archipelago were subjected to PCR amplification of a partial
 region of <em>16S rRNA</em> (506 bp). Of these, only 261
 samples were successfully amplified and sequenced. As a result, a total of
 23 <em>16S rRNA</em> haplotypes of <em>L. japonica
 </em>were detected. Combined with 11 previously known southern
 Chinese haplotypes of <em>16S rRNA</em> from 126 individuals,
 we totaled 34 <em>16S rRNA</em> haplotypes from 387
 <em>L. japonica</em> individuals in ten localities.
description: Supplementary Data S1: Nucleotide sequence alignment of 106
 <em>COI </em>haplotypes of <em>Liolophura
 japonica</em> with an outgroup. Supplementary
 Data S2: Nucleotide sequence alignment of 34 <em>16S rRNA</em>
 haplotypes of <em>Liolophura japonica </em>with an
 outgroup. Supplementary
 Data S3: Nucleotide sequence alignment of 106 <i>COI</i>
 haplotypes of <i>Liolophura japonica, Liolophura koreana
 </i>sp. nov., and <i>Liolophura sinensis</i> sp. nov.,
 one <i>COI</i> haplotype of<i> Liolophura
 tenuispinosa</i>, and 14 <i>COI</i> haplotypes of eight
 <i>Acanthopluera</i> congeneric species with an outgroup
 <i>Tonicia forbesii</i>.