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Articles

Meretrix taiwanica (Bivalvia: Veneridae), a previously misidentified new species in Taiwan

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Pages 12-21 | Received 18 Jun 2020, Published online: 30 Mar 2023

Figures & data

Figure 1. The type locality of Meretrix taiwanica sp. n. in the Tamsui River estuary, northern Taiwan.

Figure 1. The type locality of Meretrix taiwanica sp. n. in the Tamsui River estuary, northern Taiwan.

Figure 2. A, Environment of type locality; B, local fisherman catches Asian hard clams in single small boat; C, use of a bull raker as harvesting gear; D, harvested wild Asian hard clams.

Figure 2. A, Environment of type locality; B, local fisherman catches Asian hard clams in single small boat; C, use of a bull raker as harvesting gear; D, harvested wild Asian hard clams.

Figure 3. Morphometric measurements of right valve and shell. L: shell length, H: shell height, B: shell breadth, AL: anterior shell length, SW: socket width, SL: socket length, UH: upper shell height, LPM: length of posterior dorsal margin, HPM: height of posterior dorsal margin, LL: ligament length, and PL: pallial sinus length.

Figure 3. Morphometric measurements of right valve and shell. L: shell length, H: shell height, B: shell breadth, AL: anterior shell length, SW: socket width, SL: socket length, UH: upper shell height, LPM: length of posterior dorsal margin, HPM: height of posterior dorsal margin, LL: ligament length, and PL: pallial sinus length.

Table 1. Table of species, sample collecting localities and GenBank accession numbers that were used in this study.

Figure 4. A, Holotype, FRIM10028, paired valves; B, inner shell of right valve of holotype, aa: anterior adductor scar, pl: pallial line, ps: pallial sinus, pa: posterior adductor scar; C, paratype, FRIM10029; D, paratype, FRIM10030.

Figure 4. A, Holotype, FRIM10028, paired valves; B, inner shell of right valve of holotype, aa: anterior adductor scar, pl: pallial line, ps: pallial sinus, pa: posterior adductor scar; C, paratype, FRIM10029; D, paratype, FRIM10030.

Figure 5. Colour patterns of Meretrix taiwanica sp. n., FRIM10031.

Figure 5. Colour patterns of Meretrix taiwanica sp. n., FRIM10031.

Table 2. Measurements (in mm) of type specimens of Meretrix taiwanica sp. n.

L: shell length; H: shell height; AL: anterior shell length; SW: socket width; SL: socket length; UH: upper shell height; LPM: length of posterior dorsal margin; HPM: height of posterior dorsal margin; B: shell breadth; LL: ligament length; PL: pallial sinus length.

Figure 6. Shells of hard clams A, Meretrix taiwanica sp. n.; B, M. petechialis; C, M. lusoria; D, Cytheraea formosa (unavailable name-bearing types, syntype, digital image cited from BMNH HP collection, 20120227).

Figure 6. Shells of hard clams A, Meretrix taiwanica sp. n.; B, M. petechialis; C, M. lusoria; D, Cytheraea formosa (unavailable name-bearing types, syntype, digital image cited from BMNH HP collection, 20120227).

Table 3. Ten characters standardised against shell length calculated in M. taiwanica sp. n. (N = 70), M. petechialis (N = 17), M. lusoria (N = 24) and C. formosa (N = 2) (unavailable name-bearing types). Avg.: mean, Std.: standard deviation, L: shell length, H: shell height, B: shell breadth, AL: anterior shell length, SW: socket width, SL: socket length, UH: upper shell height, LPM: length of posterior dorsal margin, HPM: height of posterior dorsal margin, LL: ligament length, and PL: pallial sinus length.

Figure 7. Two-dimensional scatterplots of canonical discriminant analysis. A, Analysis including the species Meretrix taiwanica sp. n., M. petechialis, M. lusoria and C. formosa; B, analysis including the species Meretrix taiwanica sp. n., M. petechialis and M. lusoria.

Figure 7. Two-dimensional scatterplots of canonical discriminant analysis. A, Analysis including the species Meretrix taiwanica sp. n., M. petechialis, M. lusoria and C. formosa; B, analysis including the species Meretrix taiwanica sp. n., M. petechialis and M. lusoria.

Table 4. Centroids of canonical variates (Can.) 1 and 2 for 10 standardised characters of Meretrix taiwanica sp. n., M. petechialis, and M. lusoria. L: shell length, H: shell height, B: shell breadth, AL: anterior shell length, SW: socket width, SL: socket length, UH: upper shell height, LPM: length of posterior dorsal margin, HPM: height of posterior dorsal margin, LL: ligament length, and PL: pallial sinus length.

Figure 8. Phylogenetic tree constructed for Meretrix spp. and reference sequences based on the cytochrome c oxidase I gene barcode sequence. Branch support values estimated by bootstrap pseudo-replicates in maximum parsimony and neighbour-joining are displayed above each branch. A minus sign (-) indicates that the bootstrap values were <75%.

Figure 8. Phylogenetic tree constructed for Meretrix spp. and reference sequences based on the cytochrome c oxidase I gene barcode sequence. Branch support values estimated by bootstrap pseudo-replicates in maximum parsimony and neighbour-joining are displayed above each branch. A minus sign (-) indicates that the bootstrap values were <75%.