Siphonaria sirius Pilsbry, 1894

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 sirius Pilsbry, 1894

Siphonaria sirius Pilsbry 1894: 9 , 10; Pilsbry 1895: 5, 6, pl. 6, figs. 23–28; Hirase 1941: 94, pl. 121, fig. 16; Hubendick 1945: 29 (cited from Jenkins and Köhler (2024)); Kuroda and Habe 1952: 86 (cited from Jenkins and Köhler (2024)); Azuma 1960: 62 (cited from Jenkins and Köhler (2024)); Kuroda 1960: 43 (cited from Jenkins and Köhler (2024)); Baker 1964: 159 (cited from Jenkins and Köhler (2024)); Shikama 1964: 6 (cited from Jenkins and Köhler (2024)); Habe and Igarashi 1967: 28 (cited from Jenkins and Köhler (2024)); Inaba 1983: 145 (cited from Jenkins and Köhler (2024)); Trew 1983: 7 (cited from Jenkins and Köhler (2024)); Je 1989: 29 [checklist]; Morton and Morton 1983: 298, pl. 1 K (cited from Jenkins and Köhler (2024)); Hylleberg and Kilburn 2003, 2003: 133; White and Dayrat 2012: 68 [checklist]; Dayrat et al. 2014: 269, fig. 5 H; Jenkins and Köhler 2024: 115–118, figs. 43 E, F, O, P, 44 D, E.

Siphonaria (Siphonaria) sirius : Hubendick 1946: 50, 51, pl. 3, figs. 24–27.

Siphonaria (Mestosiphon) sirius : Habe and Kikuchi 1960: 60 (cited from Jenkins and Köhler (2024)); Kira 1962: 200, 201, text-fig, pl. 69, fig. 12 a, b (cited from Jenkins and Köhler (2024)); Habe 1971: 15, pl. 4, fig. 12 (cited from Jenkins and Köhler (2024)).

Anthosiphonaria sirius : Kuroda et al. 1971: 483, 484, fig. 9; Inaba 1983: 145 (cited from); Je 1989: 29 [checklist]; Choe 1992: 748, 749, pl. 126, fig. 223; Fukuda et al. 1992: 76, pl. 23, fig. 361 a, b (cited from Jenkins and Köhler (2024)).

Siphonaria laciniosa forma sirius: Christiaens 1980 a: 79.

Siphonaria laciniosa : Springsteen and Leobrera 1986: 285, pl. 81, fig. 19 (non Siphonaria laciniosa (Linneaus, 1758) ; cited from Jenkins and Köhler (2024)).

Siphonaria subatra : Je 1989: 29 [checklist].

Siphonacmea oblongata : Je 1989: 29 [checklist].

Siphonaria (Anthosiphonaria) sirius : Kwon et al. 1993: 334, fig. 61-2; Higo et al. 1999: 402, G 4977 [checklist]; Kwon 2001: 191, fig. 725; Min et al. 2004: 336, fig. 1058; Okutani 2000: 815, pl. 405, fig. 5; Noseworthy et al. 2007: 90 [checklist]; Okutani 2017: 1101, pl. 403. fig. 5.

Materials

Type status: Other material. Occurrence: individualCount: 1; occurrenceID: D54B007E-530E-5A64-9E37-238C909DFC8B; Taxon: scientificName: Siphonaria sirius ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: sirius ; scientificNameAuthorship: Pilsbry, 1894; 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: individualCount: 1; occurrenceID: C0A81431-17F4-52C1-891F-62FF72C4302D; Taxon: scientificName: Siphonaria sirius ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: sirius ; scientificNameAuthorship: Pilsbry, 1894; Location: country: Korea; locality: Sagye-ro, Andeok-myeon, Seogwipo-si, Jeju-do ; verbatimCoordinates: 33°13'58.7"N 126°22'23.8"E; verbatimCoordinateSystem: 33 ° 13 ' 13.2 " N 126 ° 17 ' 42.0 " E; Event: eventDate: 2022-04-21

Type status: Other material. Occurrence: individualCount: 2; occurrenceID: BEE8EC41-E8D8-5759-BB91-328F2C2C0A3E; Taxon: scientificName: Siphonaria sirius ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: sirius ; scientificNameAuthorship: Pilsbry, 1894; Location: country: Korea; locality: Irun-myeon ,, Geoje-si, Gyeongsangnam-do ; verbatimCoordinates: 34°58'34.9"N 128°41'18.18"E; Event: eventDate: 2023-04-19

Type status: Other material. Occurrence: individualCount: 3; occurrenceID: 2213E690-E902-5F33-99A8-212A4C10304D; Taxon: scientificName: Siphonaria sirius ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: sirius ; scientificNameAuthorship: Pilsbry, 1894; Location: country: Korea; locality: Namyang-ri, Seo-myeon, Ulleung-gun, Gyeongsangbuk-do ; verbatimCoordinates: 37°27'35.6"N 130°51'27.0"E; Event: eventDate: 2023-05-23

Type status: Other material. Occurrence: individualCount: 2; occurrenceID: 37D006D8-B765-5917-A845-CD6DD8473CD9; Taxon: scientificName: Siphonaria sirius ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: sirius ; scientificNameAuthorship: Pilsbry, 1894; Location: country: Korea; locality: Mendehaean-gil, Tongyeong-si, Gyeongsangnam-do ; verbatimCoordinates: 34°50'37.8"N 128°26'36.0"E; Event: eventDate: 2023-06-21

Type status: Other material. Occurrence: individualCount: 1; occurrenceID: 2A53BAB4-3A3B-59CA-8E8A-716A5BC80FD6; Taxon: scientificName: Siphonaria sirius ; kingdom: Animalia; phylum: Mollusca; class: Gastropoda; order: Siphonariida ; family: Siphonariidae ; genus: Siphonaria ; specificEpithet: sirius ; scientificNameAuthorship: Pilsbry, 1894; Location: country: Korea; locality: Guryongpo-eup, Nam-gu, Pohang-si, Gyeongsangbuk-do ; verbatimCoordinates: 35°57'05.7"N 129°33'04.4"E; Event: eventDate: 2023-07-23

Description

Measurements: SL 11.23–19.63 mm, SW 9.09–15.62 mm, SH 2.87–4.93 mm.

Shell (Fig. 2 d ) solid, oval, small to medium in size (in examined specimens, SL 11.23–19.63 mm), low in height (about 1 / 4 of its length). Exterior colour greyish-brown or blackish-brown. Shell surface with 5–11 strong, white-coloured primary radial ribs. Interspaces between the primary radial ribs with 1–8 thinner secondary ribs, coloured white, sometimes same as shell colour. Apex often eroded, located central of the shell. Shell margin prominently undulated by primary ribs. Anterior slope slightly convex, posterior slope nearly straight. Siphonal groove protruded with one radial rib on outer shell surface. Interior colour reddish-brown to black with white bands, sometimes white or pale-coloured at centre.

Radula (Fig. 3 e , f ) dentition formulae 34: 1: 34 (in specimens measuring SL 14.69 mm, SW 11.80 mm, SH 3.89 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 e ) short, approximately one-third length of lateral tooth, bud-shaped, middle widest, tapering gently towards the top with sharply-pointed cusp. Innermost lateral teeth (first 15 lateral teeth), each tooth consisting of mesocone and ectocone; mesocone bicuspid, with U-shaped cleft; ectocone shorter, sharp (Fig. 3 e ). Outermost lateral teeth (remaining 19 lateral teeth) with short and sharply-pointed endocone, ectocone and mesocone; mesocone subquadrate (Fig. 3 f ).

Distribution

Korea, China, Japan, Philippines, Singapore, Indonesia (Sumatra Island) and Vietnam.

Type locality: Japan; Sagami, Kashiurazaki, Boshiu (Boso Peninsula).

Habitat: On rocky substrate in middle to low intertidal zones (Fig. 2 d G).

Taxon discussion

This species is clearly distinguished from other Korean sympatric species ( S. acmaeoides and S. japonica ) by its flat shell, remarkably extended white radial ribs, siphonal groove with a single radial rib and pale-coloured inner centre (Fig. 2 d ). It closely resembles S. atra Quoy and Gaimard, 1833 , by having a flat shell and strongly stretched radial ribs. Christiaens (1980 a) noted that S. sirius represents one of the three forms of S. laciniosa (Linnaeus, 1758) ; ( S. laciniosa forma sirius, S. laciniosa forma atra (representing S. atra Quoy and Gaimard, 1833 ) and S. laciniosa forma subatra (representing S. subatra Pilsbry, 1904 ). He reported no differences in niche selection between S. atra and S. sirius , both of which inhabit highly exposed rocky substrates in the low tidal zone at Ping Chau, Hong Kong. However, the two species differ in colouration and the number of ribs in the siphonal groove. While S. atra has a dusky brown shell with radial ribs of the same colour (sometimes paler than the interspaces) and a siphonal groove with two radial ribs, S. sirius is characterised by a black or dark brown-coloured shell with solid white radial ribs and a siphonal groove with only one radial rib. In the radula formula, as mentioned in the cases of S. acmaeoides and S. japonica , Siphonaria species exhibits high levels of intraspecific variation. Similarly, the radula formulae of S. sirius reported in previous studies showed considerable variation depending on the authority, ranging from 40: 1: 40 ( Hubendick 1946) to 34: 1: 34 ( Christiaens 1980 a). The radula formula (34: 1: 34) observed in this study is consistent with the finding of Christiaens (1980 a). The phylogenetic tree shows that S. sirius forms a sister group with S. atra and S. subatra receiving 99 % bootstrap value (Fig. 4 ). The p - distances within S. sirius species range from 0.16 % to 0.79 %, while this species shows high sequence divergence from other congeneric species ranging from 22.38 % ( S. atra ) to 31.90 % ( S. japonica ) (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 d. G S. sirius on rocky substrate of Korea, Jeju; H Dorsal, ventral and lateral view of S. sirius from Geoje.

Figure 3 e. S. sirius - Details of rachidian teeth (arrowhead) and innermost lateral teeth.

Figure 3 f. S. sirius - Details of outermost lateral teeth.