Siphonaria japonica ( Donovan, 1824 )

Kim, Yukyung, Park, Jina, Hwang, Ui Wook & Park, Joong-Ki, 2025, Taxonomic review of Korean Siphonaria species (Mollusca, Gastropoda, Siphonariidae), Biodiversity Data Journal 13, pp. e 139388-e 139388 : e139388-

Siphonaria japonica ( Donovan, 1824)

Patella japonica Donovan 1824: pl. 79; Kuroda et al. 1971: 483, pl. 64, fig. 7; White and Dayrat 2012: 64 [checklist].

? Siphonaria radiata : Adams and Reeve 1850: 69, pl. 13, fig. 2.

? Siphonria radians : Adams and Adams 1855: 271; Hubendick 1946: 43.

Siphonaria cochleariformis : Reeve 1856: pl. 6, fig. 28; Hubendick 1946: 43, pl. 2, figs. 33–35; Kuroda et al. 1971: 483, pl. 64, fig. 7.

Siphonaria japonica : Hanley 1858: 152 [checklist]; Pilsbry 1920: 141; Abe 1940: 59 (cited from Jenkins and Köhler (2024)); Hirase 1941: 94, pl. 121, fig. 12; Kuroda 1941: 137; Hubendick 1945: 27, fig. 34, 36, 39, 41 (cited from Jenkins and Köhler (2024)); Kuroda and Habe 1952: 86 (cited from Jenkins and Köhler (2024)); Lee 1956: 79; Kuroda 1960: 43 (cited from Jenkins and Köhler (2024)); Habe and Kikuchi 1960: 64 (cited from Jenkins and Köhler 2024); Shikama 1964: 6 (cited from Jenkins and Köhler (2024)); Berry 1977: 197, fig. 19 (cited from Jenkins and Köhler (2024)); Lee and Chao 2003: 35, pl. 6, fig. 173; Qi 2004: 198, pl. 108, fig. E; Dayrat et al. 2014: 266, fig. 3 B; Jenkins and Köhler 2024: 31–34, figs. 13 A – L, Q – S, 15 B – E.

Siphonaria alterniplicata : Grabau and King 1928: 237, pl. 11, fig. 117; Hubendick 1946: 62; White and Dayrat 2012: 60 [checklist]; Coan et al. 2015: 221, fig. 38 A, B.

Siphonaria (Sacculosiphonaria) japonica : Hubendick 1946: 42, pl. 2, figs. 29–32; Kira 1962: 201, pl. 69, fig. 8 a, b (cited from Jenkins and Köhler (2024)); Habe 1971: 15, pl. 4, fig. 16 (cited from Jenkins and Köhler (2024)); Yoo 1976: 89, pl. 19, figs. 1–4; Christiaens 1980 a: 79; Christiaens 1980 b: 466, 467; Je 1989: 89 [checklist]; Fukuda et al. 1992: 76, pl. 23, fig. 360 a, b (cited from Jenkins and Köhler (2024)); Kwon et al. 1993: 334, fig. 61-1; Okutani 2000: 815, pl. 405, fig. 6; Kwon 2001: 191, fig. 723; Hamamura 2004: 115; Min et al. 2004: 335, fig. 1056; Noseworthy et al. 2007: 90 [checklist]; Okutani 2017: 1101, pl. 403, fig. 6.

Sacculosiphonaria japonica : Kuroda et al. 1971: 483, pl. 64, fig. 7; Trew 1983: 9 (cited from Jenkins and Köhler (2024 )); Choe 1992: 747, 748, pl. 125, fig. 222.

Siphonaria (Mastosiphon) sirius : Yoo 1976: 89, pl. 19, fig. 5 (non Siphonaria sirius Pilsbry 1894 ).

Siphonaria acmaeoides : Kwon et al. 1993: 335, fig. 61-3 (non- Siphonaria acmaeoides Pilsbry 1894 ).

Siphonaria (Planesiphon) acmaeoides : Kwon 2001: 191, fig. 724; Min et al. 2004: 337, fig. 1057 (non- Siphonaria acmaeoides in Pilsbry (1894)).

Siphonaria japonica tall form: Yokogawa et al. 2010: fig. 1 A.

Materials

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894428 – NIBRIV 0000894447 ; individualCount: 20; occurrenceID: 8CB2FFA8-7177-5D58-9987-D944894409D8; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Namyang-ri, Seo-myeon, Ulleung-gun, Gyeongsangbuk-do ; verbatimCoordinates: 37 ° 27 ' 34.5 " N, 130 ° 51 ' 27.4 " E; Event: eventDate: 2011-11 - 13

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894458 – NIBRIV 0000894467 ; individualCount: 10; occurrenceID: E2FA26B9-DF79-5C3B-BAA0-2A7982854C38; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Jeonjin-ri, Ganghyeon-myeon, Yangyang-gun, Gangwon-do ; verbatimCoordinates: 38 ° 07 ' 31.5 " N, 128 ° 37 ' 52.3 " E; Event: eventDate: 2014-04 - 09

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894468 – NIBRIV 0000894487 ; individualCount: 20; occurrenceID: 59D7504B-74E8-514D-BCCA-3C6F3557C300; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Jukbyeon-ri, Jukbyeon-myeon, Uljin-gun, Gyeongsangbuk-do ; verbatimCoordinates: 37 ° 3 ' 32.50 " N, 129 ° 25 ' 43.92 " E; Event: eventDate: 2014-04 - 09

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894448 NIBRIV 0000894450 ; individualCount: 3; occurrenceID: 8451E1F2-DB21-501A-A3C9-52209A958584; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Namae-ri, Hyeonnam-myeon, Yangyang-gun, Gangwon-do ; verbatimCoordinates: 37 ° 56 ' 33.7 " N, 128 ° 47 ' 17.8 " E; Event: eventDate: 2014-08 - 24

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894548 - NIBRIV 0000894562 ; individualCount: 15; occurrenceID: 7E7E0FC6-5FF9-5A57-A3BD-6F006D828021; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Samyang 1 (il) - dong Jeju-si Jeju-do ; verbatimCoordinates: 33 ° 31 ' 34.6 " N, 126 ° 35 ' 09.0 " E; Event: eventDate: 2015-12 - 21

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894451 - NIBRIV 0000894457 ; individualCount: 7; occurrenceID: CC219B8C-1E0B-5581-B327-D492B0178063; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Namae-ri, Hyeonnam-myeon, Yangyang-gun, Gangwon-do ; verbatimCoordinates: 37 ° 56 ' 33.7 " N, 128 ° 47 ' 17.8 " E; Event: eventDate: 2016-03 - 02

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894408 - NIBRIV 0000894424 ; individualCount: 17; occurrenceID: 2CD256A6-3489-5322-9FA4-8F75AF0BCF39; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Dokdo-ri, Ulleung-eup, Ulleung-gun, Gyeongsangbuk-do ; verbatimCoordinates: 37 ° 14 ' 20.12 " N, 131 ° 52 ' 05.74 " E; Event: eventDate: 2016-06 - 22

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894508 - NIBRIV 0000894527 ; individualCount: 20; occurrenceID: 0D774AF9-C5DA-5C87-B0AE-26873ED2A1F7; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Gahak-ri, Jisan-myeon, Jindo-gun, Jeollanam-do ; verbatimCoordinates: 34 ° 25 ' 48.1 " N, 126 ° 05 ' 55.6 " E; Event: eventDate: 2016-07 - 08

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894563 - NIBRIV 0000894564 ; individualCount: 2; occurrenceID: EE49E3D2-2BA0-5D88-8772-0303B4B71649; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Ojo-ri, Seongsan-eup, Seogwipo-si, Jeju-do ; verbatimCoordinates: 33 ° 28 ' 14.8 " N, 126 ° 55 ' 21.9 " E; Event: eventDate: 2017-06 - 27

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894565 - NIBRIV 0000894567 ; individualCount: 3; occurrenceID: 0CBFE4F7-A55D-52DF-AAC8-16500149F3AD; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Hwasun-ri, Andeok-myeon, Seogwipo-si, Jeju-do ; verbatimCoordinates: 33 ° 14 ' 20.7 " N, 126 ° 20 ' 01.6 " E; Event: eventDate: 2017-06 - 28

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894488 - NIBRIV 0000894507 ; individualCount: 20; occurrenceID: BEF4F2B8-098D-5566-8920-C4545FAEE777; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Seopo-ri, Deokjeok-myeon, Ongjin-gun, Incheon ; verbatimCoordinates: 37 ° 13 ' 03.16 " N, 126 ° 06 ' 55.67 " E; Event: eventDate: 2018-04 - 17

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894528 - NIBRIV 0000894547 ; individualCount: 20; occurrenceID: B872D531-A994-59F3-A5E9-E1FDD9EAB14F; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Gujora-ri, Irun-myeon, Geoje-si, Gyeongsangnam-do ; verbatimCoordinates: 34 ° 48 ' 31.93 " N, 128 ° 41 ' 25.97 " E; Event: eventDate: 2018-06 - 12

Type status: Other material. Occurrence: catalogNumber: NIBRIV 0000894425 - NIBRIV 0000894427 ; individualCount: 3; occurrenceID: 3B25F340-A40E-5225-BBC0-AC7D16CA5F33; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Dokdo-ri, Ulleung-eup, Ulleung-gun, Gyeongsangbuk-do ; verbatimCoordinates: 37 ° 14 ' 20.12 " N, 131 ° 52 ' 05.74 " E; Event: eventDate: 2021-06 - 02

Type status: Other material. Occurrence: individualCount: 1; occurrenceID: FB198DA4-1645-5901-BDFA-506AE0CDD712; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Guryongpo-eup, Nam-gu, Pohang-si, Gyeongsangbuk-do ; verbatimCoordinates: 35 ° 57 ' 11.5 " N, 129 ° 32 ' 50.4 " E; Event: eventDate: 2023-07 - 12

Type status: Other material. Occurrence: individualCount: 1; occurrenceID: 1B68A9AE-75A2-505F-8F9E-E9AE8E3C17F9; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Daejin-ri, Hyeonnae-myeon, Goseong-gun, Gangwon-do ; verbatimCoordinates: 38 ° 29 ' 57.1 " N, 128 ° 25 ' 38.7 " E; Event: eventDate: 2024-03 - 20

Type status: Other material. Occurrence: individualCount: 3; occurrenceID: C26236C2-BD2D-5ED5-94A0-A09287579017; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Onpyeong-ro, Seongsan-eup, Seogwipo-si, Jeju-do ; verbatimCoordinates: 33 ° 24 ' 03.7 " N, 126 ° 54 ' 17.7 " E; Event: eventDate: 2024-07 - 28

Type status: Other material. Occurrence: individualCount: 2; occurrenceID: DE709C43-9BAD-5511-BB20-64DF8FE5144F; Taxon: scientificName: Siphonaria japonica ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: japonica ; scientificNameAuthorship: ( Donovan, 1824); Location: country: Korea; locality: Sagye-ro, Andeok-myeon, Seogwipo-si, Jeju-do ; verbatimCoordinates: 33 ° 13 ' 13.2 " N 126 ° 17 ' 42.0 " E; Event: eventDate: 2022-04 - 21

Description

Measurements: SL 10.5–15.45 mm, SW 7.5–12.24 mm, SH 2.81–4.7 mm.

Shell (Fig. 2 c ) thin, oval, small size (in examined specimens, SL 10.5–15.45 mm), medium-high in height (2 / 7 of its length). Exterior colour greyish-brown. Shell surface with 17–23 thin, yellowish white-coloured primary radial ribs. Interspaces between radial ribs sometimes with 1–2 secondary ribs. Apex eroded, located centrally in posterior one-third of shell. Shell margin weakly undulated. Anterior slope slightly convex, posterior slope shorter, nearly straight. Siphonal groove weakly prominent with two radial ribs on outer shell surface. Interior colour reddish-brown.

Radula (Fig. 3 c , d ) dentition formulae 29: 1: 29 (in specimens measuring SL 10.54 mm, SW 7.47 mm, SH 2.81 mm). Each transverse row with narrow central rachidian tooth flanked by symmetrical half rows with lateral teeth, decreasing in size outwards. Rachidian tooth (Fig. 3 c ) short, - approximately one-third length of lateral tooth, with sharply pointed cusp. Innermost lateral teeth (first 17 lateral teeth), each tooth consisting of mesocone and ectocone; mesocone with bicuspid or unicuspid (Fig. 3 c ); ectocone shorter, pointed. Outermost lateral teeth (remaining 12 lateral teeth) consisting of endocone, ectocone and mesocone; mesocone paddle-shaped, not angled; endocone and ectocone short, sharply pointed (Fig. 3 d ).

Distribution

Korea, China, Japan and Taiwan.

Type locality: Japan.

Habitat: On rocky substrate in low to high intertidal zones (Fig. 2 c E).

Taxon discussion

Jenkins and Köhler (2024) designated a neotype for S. japonica due to the absence of the original type specimens and provided a detailed description of the shell morphology, reproductive system and morphological features of spermatophore. The shell morphology of the Korean S. japonica specimens match es well both by Donovan (1824) ' s original description and the observations by Jenkins and Köhler (2024). Nevertheless, moderate variations in the number of ribs were observed in this study, with the number of primary ribs ranging from 17 to 23 and secondary ribs ranging from 1 to 2. These ranges differ from those reported by Jenkins and Köhler (2024), which included up to 20 primary ribs and 2 to 3 secondary ribs. In addition, Jenkins and Köhler (2024) considered the shell images of Figs. 1 and 4 of S. japonica described by Yoo (1976) to likely represent misidentification, without providing detailed information on their interpretation. Upon re-examination of the Figs. 1 and 4, we observed that the specimens show characteristics consistent with S. japonica , including 20–25 primary ribs with secondary rib interstices (though the exact number is ambiguous) and two primary ribs on the siphonal groove. Based on our integrated analyses of the morphology (including the number of radial ribs on the shell surface) and molecular sequence data, we have concluded that all the shell images in Yoo (1976), including Figs. 1 and 4, represent within the normal range of shell variations typically observed in S. japonica . In radula morphology, Hubendick (1946) provided a brief sketch of radula characters, based on only two specimens in his description of S. japonica . He provided a radula formula ranging from 32: 1: 32 to 40: 1: 40 and noted the presence of an ectocone on the innermost lateral teeth. Our examination of the Korean specimens revealed a radula formula of 29: 1: 29, which differs from those reported in Hubendick (1946), while the presence of an ectocone on the innermost lateral teeth was consistent with his findings. These observations suggest that the radula formula can vary within the same species.

S. japonica is commonly found in intertidal zones along the Korean coast, often occurring alongside S. acmaeoides and S. sirius (Fig. 2 a A, Fig. 2 d G). Their wide range of distribution and variations in shell morphology can lead to confusion in identification, resulting in past misidentifications in Korean illustrations as S. sirius ( Yoo 1976) and S. acmaeoides ( Kwon et al. 1993, Kwon 2001, Min et al. 2004). However, this species can be distinguished from other sympatric Siphonaria species by its thinner, regularly spaced primary ribs, siphonal groove with two radial ribs, undulated margin and dark brown-coloured interior (Fig. 2 c F). Yokogawa et al. (2010) described two types from S. japonica , based on the combination of morphological, molecula, and ecological data, as the “ tall form ” and the “ short form ”. The tall form is characterised by weak radial ribs over the shell margin and alternating sized (thick and thin) radial ribs, while the short form has projected radial ribs over the shell margin and generally thick radial ribs. The Korean S. japonica morphologically matches the “ tall form ”. A comprehensive analysis of shell morphological data, coupled with molecular sequence information from broader sampling of this species, is required to confirm whether the “ short form ” of S. japonica is also distributed along the Korean sea coast, as previously reported in Japan ( Yokogawa et al. 2010). Our phylogenetic tree indicates that S. japonica is positioned basal amongst selected Siphonariidae species in the north-western Pacific, with 99 % bootstrap support value (Fig. 4 ). This species exhibits relatively high sequence divergence from other Siphonaria species, ranging from 28.89 % ( S. zelandica ) to 33.81 % ( S. subatra ) (Table 2).

Figures

Figure 4. Phylogenetic relationships amongst some selected NWP Siphonaria species inferred from the Maximum Likelihood method using the mtDNA cox 1 sequences. The bootstrap supporting values (≥ 50 %) are indicated on the branches. Asterisks (*) represents the mtDNA cox 1 sequences determined in this study.

Figure 2 c. E S. japonica on rocky substrate of Korea, Jeju; F Dorsal, ventral and lateral view (left) of S. japonica from Goseong.

Figure 3 c. S. japonica - Details of rachidian teeth (arrowhead) and innermost lateral teeth.

Figure 3 d. S. japonica - Details of outermost lateral teeth.

Figure 2 a. A S. acmaeoides on rocky substrate of Korea, Jeju; B Dorsal, ventral and lateral view (left) of S. acmaeoides from Jeju.

Figure 2 d. G S. sirius on rocky substrate of Korea, Jeju; H Dorsal, ventral and lateral view of S. sirius from Geoje.