Siphonaria normalis Gould, 1846

Jenkins, Bruce & Köhler, Frank, 2024, Hidden in plain sight: Systematic review of Indo-West Pacific Siphonariidae uncovers extensive cryptic diversity based on comparative morphology and mitochondrial phylogenetics (Mollusca, Gastropoda), Megataxa 13 (1), pp. 1-217 : 79-82

Siphonaria normalis Gould, 1846

( Figs 31A–I, O, S–U , 32A–D )

Siphonaria normalis Gould 1846: 12 (type locality: ‘Sandwich Islands’ [Hawaii]).— Gould 1848: 154; 1852: 359; H. Adams & A. Adams 1855 (in 1853–1858): 271; Gould 1856: 13, fig. 468a–b; Hanley 1858b: 152; H. Adams & A. Adams 1863: 271; Paetel 1883: 178; 1889: 429; Pilsbry 1920b: 379; Edmondson 1946: 188, fig. 102a; Hubendick 1946: 63; 1947b: 2, figs 3a–i, 4a–i, 5, 8–10; Morris 1952: 206, pl. 40, fig. 17; Johnson 1964: 116; Cook 1969: 679; Cernohorsky 1972: 210, pl. 60, fig. 2; Cook 1976: 34; Galindo 1977: 416; Coles 1981: 11; Trew 1983: 8; Jenkins 1984: 117; White & Dayrat 2012: 62, 2014: 266; Gonzàlez-Wevar et al. 2018: 5, fig. 1; Krug et al. 2022: 5.

Siphonaria normalis var. lirata — Pilsbry 1920b: 37980 (not S. lirata Reeve, 1856 ).

Planesiphon soranus Iredale 1940: 441 , fig. 20, 21 (type locality: Townsville, Queensland).— White & Dayrat 2012: 67.

Siphonaria ‘ normalis group, unit 14’ (in part)— Dayrat et al. 2014: 267, fig. 3 P–S.

Siphonaria cf normalis (unit 52)— Ossenbrügger et al. 2023: fig. 2c–o.

Material examined. Type material. Syntype of Siphonaria normalis Gould, 1846 from Hawaii, United States, North Pacific Ocean ; coll. Carpenter ( USNM 15346 , Fig. 31A ) .

Lectotype of P. soranus Iredale, 1940 , present designation, from Townsville Qld , Australia; coll. 1929 ( AM C.103709 , Fig. 31D ). Seven paralectotypes, same data as lectotype ( AM C.124989 ). Two paralectotypes, same data as lectotype ( MV F13840 ).

Other, non-type material. Marquesas: Baie des Vierges , Fatu Hiva , 10°27,84’S, 138°39,97’W ( MNHN IM-2013-74897 p [M570, SK508], IM-2013-74898 p [M569], IM-2013-74899 p [M565]). Hawaii, Oahu: N end Waikiki Beach, 21°15.743’N, 157°49.307’W ( AM C.584887 p [M293]); N end Waikiki, 21°16.646’N, 157°50.048’W ( AM C.585622 5p, C.584886 p [SK210], C.585930 p [SK209]). Maui: Hanakao’o Beach, 20°54.564’N, 156°41.310’W ( AM C.585929 p [M296]); Makalua-puna Point, 21°54.586’N, 156°41.338’W ( AM C.585555 3p); Ho’okipa Beach, 20°56.029’N, 156°21.411’W ( AM C.584892 p [SK212]). Guam: Umatac Bay , N end, 13°17.917’N, 144°39.494’E ( AM C.585325 p C.584869 p [SK142], C.585493 p [M347], C.585494 p [M348]); Pago Bay , below UoG Marine Lab, 13°25.645’N, 144°47.927’E ( AM C.585996 10+p); Tanguisson Beach, S end, 13°32.549’N, 144°48.443’E ( AM C.585994 2p, C.584873 p [M343], C.584874 p [M439]). Fiji, Viti Levu: Vuda Point Marina seawall, 17°40.878’S, 177°23.009’E ( AM C.585970 20+p, C.584866 p [SK115 protoconch C9], C.584867 p [M286], C.584868 p[M287]). PNG: Sek Is., 05°04,7’S, 145°48,9’E ( MNHN IM-2013-13133 p [M558], IM-2013-13135 p [M562]); Wonad I., 05°08,1’S, 145°49,3’E ( MNHN IM-2013-15280 p [M563]); Riwo waters, 05°08,9’S, 145°48,2’E ( MNHN IM-2013-15250 p [M555] IM-2013- 15251 p [M554]). NC, Lifou: We Baie de Chateaubriand E coast ( AM C.585396 10p, C.584946 p [M388], C.584947 p [M389]). S of Pouebo 20°25.950’S, 164°39.251’E NC04-2 ( AM C.585006 p [M381], C.585007 p [M382]); Bonhomme de Bourail , La Roche Percee, 21°36.487’S, 165°27.423’E ( AM C.585013 p [M370], C.585014 p [M371]); Presqu’ile de Ouano La Foa , 20°51.434’S, 165°48.479’E ( AM C.595911 6p). Australia, Qld: Umagico, 10°53.125’S, 142°20.799’E ( AM C.585178 p [SK195]); Capt Billy Landing, 11°38.019’S, 142°51.472’E ( AM C.585415 10+p, C.584792 p [M180], C.584793 p [M181], C.584794 p [M402]); S of Bathurst Head, 14°17.583’S, 144°11.845’E ( AM C.585348 10p); Lizard Is, bch rock, 14°40.730’S, 145°26.838’E ( AM C.585643 5p); Lizard Is, 14°40.908’S, 145°27.007’E ( AM C.585566 4p, C.585175 p [M030]); Cape Kimberley, 16°16.535’S, 145°28.737’E ( AM C.585720 9p, C.585168 p [M041], C.585169 p [M394], C.585170 p [M395], C.585171 p [M397]); Pebbly Beach Yule Reef Trinity Bay , 16°35.031’S, 145°30.823’E ( AM C.585703 8p); Gribble Pt Mission Bay Yarrabah, 16°53.781’S, 145°51.852’E ( AM C.585347 p); Mourilyan Harbour, 17°35.951’S, 146°07.583’E ( AM C.585411 10+p, C.585155 p [M012], C.585156 p [SK123]); W side Kissing Pt Townsville, 19°14.332’S, 146°48.040’E ( AM C.585672 6p, C.585146 p [M083], C.585147 p [M186], C.585148 p [M187], C.585149 p [M188], C.585931 p [SK197], C.585932 p [SK075]); Slade Pt Mackay, 21°03.813’S, 149°13.527’E ( AM C.585501 2p). Gulf of Carpentaria: Mutee Head, 10°54.682’S, 142°15.204’E ( AM C.585416 10p); Weipa, 12°37.795’S, 141°51.853’E, Q52-1 ( AM C.585450 12p); Sweers Is: 17°07.029’S, 139°35.805’E ( AM C.585645 5p), 17°07.413’S, 139°35.816’E, Q56-2 ( AM C.585350 p), Inspection Pt, 17°08.471’S, 139°36.868’E ( AM C.585417 15+p). NT: Cape Wirawawoi Nhulunbuy, 12°09.513’S, 136°46.904’E ( AM C.585530 20+p); Sandy Is Pt 11°07.862’S, 132°11.187’E ( AM C.585406 10+p); Smith Pt 2, 11°07.466’S, 132°08.538’E ( AM C.585636 5p); Luxmore Hd Melville Is, 11°20.639’S, 130°23.149’E ( AM C.585349 7p); Nightcliff Darwin, 12°22.836’S, 130°50.402’E ( AM C.585977 10+p); Cox Peninsula, 12°24.824’S, 130°40.921’E ( AM C.585978 10+p); N of Native Pt Dundee Bch, 12°42.182’S, 130°20.881’E ( AM C.585668 6p); Native Pt oyster reef Dundee Bch, 12°42.906’S, 130°20.653’E ( AM C.585413 8p); Native Pt reef Dundee Bch, 12°42.981’S, 130°20.807’E ( AM C.585381 10p) .

Taxonomic remarks. Siphonaria normalis was subsequently figured by Gould (1856: 13, pl. 30, figs 468, 468a–b). The syntype corresponds well with this figure in shell profile, dimensions and colouration. The description of P. soranus does not contain an original type designation. The figured specimen of P. soranus ( Iredale, 1940: pl. 34, figs 20–21) is herein designated as the lectotype for the stabilisation of the name ( AM C.103709). Our delineation of this species is based on comparative analyses of the morpho-anatomy and mitochondrial genetics of freshly collected topotypes of S. normalis and P. soranus and geographic series of additional specimens (Table S1). We stablish P. soranus as a junior synonym of S. normalis .

Pilsbry (1920b: 379) erroneously considered S. amara , S. nuttallii , S. lirata , S. crebricostata and S. normalis f. chirura as synonyms of S. normalis . This was followed by Cernohorsky (1972: 210). Dayrat et al. (2014: 267) recognised several independent molecular units within the normalis group (i.e., unit 12 from Thailand, unit 13 from Singapore, and unit 14 from Hawaii). These units are herein recognised as three distinct species, S. radiata (unit 12), S. costellata sp. nov. (unit 13), and S. normalis (unit 14).

External morphology. Foot sole, foot wall, mantle, cephalic folds and pneumostomal lobe evenly pale grey/cream, paler at edge foot/wall; blotches of black pigmentation on centre of cephalic folds, faintly on foot wall; mantle narrower than width of foot wall, non-translucent, covers exposed inner shell lip, edge thickened, lobed, vertical bands of black pigmentation aligned with shell rib interstices; genital pore indistinct, located on foot wall to right anterior of right cephalic fold; two small black epithelial eye spots centralised on two centrally touching cephalic folds; pneumostomal lobe long under the mantle between the right ADMs.

Shell ( Figs 31A–I, O, S–U ; Table S9). Small sized (max sl mean = 12.56 mm, SD = 2.02 mm, n = 13), circular ovate; height medium to tall; apex offset posterior and weakly left, apical sides straight to weakly convex, shell edge; protoconch direction heterostrophic, initially hooked (n = 4; Fig. 31S–T ), shell whorl dextral; growth striae prominent, radial colour banding often present, shell thickness thick; rib count (mean = 33, SD = 0.87, n = 13), primary ribs distinct, white to pale, usually radially evenly spread, fairly straight, broaden to and align with fairly flat faintly scalloped shell edge; ribs may be raised or flat,; 1–2 interspersed pale white finer secondary ribs, rib interstices darker; paired primary ribs on siphonal ridge, no more prominent than other primary ribs. Interior shell margin varies from pale tan to dark brown; white rays extend from the shell lip to over the shell margin fading to the spatula, align under primary/secondary ribs, spatula varies from pale yellow ( Fig. 31E ), pale tan ( Fig. 31B ) to dark chocolate brown ( Fig. 31F ); siphonal groove distinct, paler than shell margin or spatula; ADM scar distinct, CMS straight, paler than shell lip; thickening of shell lip common, margin becomes whitened ( Fig. 31E ).

Reproductive system ( Figs 32A, C; n = 9). Positioned within coelom under the respiratory cavity, hermaphroditic glands positioned to posterior against right foot wall and over foot sole, epiphallic parts positioned to anterior between BM and RAM; GP small, singular, positioned through foot wall behind right cephalic fold, GA small, prominent; AO very small, short, narrow, blunt, slightly bent centrally, joins to top of GA in conjunction with ED; ED short, broad, joins to back side of GA alongside AO; single short broad blunt flagellum (F1), longer than and same width as ED, join of F1 to ED indistinct, marked by connection of very small white folded EG; AO, GA and ED all muscular white tissue; BD and CD connect closely side-by-side into GA between connections of ED and AO, both ducts narrow smooth featureless, pass together through RAM connecting into MG ( BD above CD), BD longer than CD, often loop immediately in front of BC; BC large to medium, spherical, embedded in folds of MG, test translucent; SV embedded on left side of AG; HD short, thick coils, links AG to smaller yellowish granular HG; MG and AG folded, soft white tissue; sides match curvature of inner foot wall on right posterior of coelom; outer edge of MG lobed.

Spermatophore ( Figs 32B, D ). Broad head with short flagellum (length = 2.47 ± 0.195 mm, n = 3); head section cylindrical, bulbous, centrally bent, rounded tip; test thin, smooth, featureless, translucent encasing a white opaque central core; short tapering section (often looped) merges head to filamentous flagellum; head slightly shorter, wider than translucent flagellum (head length = 1.23 ± 0.45 mm, flagellum length = 1.24 ± 0.34 mm, SPM head ~ 49% of total lenght; head width = 110 ± 13 μm, flagellum width = 11 ± 0 μm, n = 3); up to 9 SPMs tightly coiled in BC of topotypic specimens ( AM C.585930).

Comparative remarks. Siphonaria normalis ( normalis group, unit 14) is the sister species of a clade containing S. fuliginata and S. madangensis sp. nov. ( Figs 1 , 4 ). These three species are closely related and differ from each other by COI distances of ≥ 5.9% ( S. fuliginata , unit 80) and ≥ 5.6% ( S. madangensis sp. nov., unit 88) (Table S8). Two other closely related species are S. campestra sp. nov. (unit 86, COI distance ≥ 18.6%) and S. costellata sp. nov. (unit 13, COI distance ≥ 7.8%) (Table S8).

Siphonaria campestra sp. nov. differs in having a shell with slightly broader ribs, predominantly primary and few secondary ribs, slightly more scalloped shell edge, darker interior, a smaller AO, shorter ED, and a thicker SPM. Siphonaria fuliginata has a much paler, thicker shell, less scalloped edge, a thicker BD, smaller BC, shorter and narrower ED, and a shorter SPM.

Throughout the range of S. normalis we found twentyseven congeners to occur in partial sympatry. Siphonaria gemina sp. nov. has a smaller shell with stronger raised ribbing and edge scalloping, more prominent siphonal ridge, a larger AO and GA, a shorter, wider BD, and a wider SPM. Siphonaria mauiensis sp. nov. (sympatric in Hawaii) has a smaller shell with more raised ribbing and weaker edge scalloping, a smaller BC, shorter BD, and a shorter SPM. Siphonaria nuttallii (sympatric in Hawaii) has a taller shell with a more central apex, slightly greater raised ribbing, stronger edge scalloping, more prominent and multi ribbed siphonal ridge, a larger AO, smaller BC, broader BD, and a longer SPM. Eight congeners are sympatric in Fiji and NC. For comparison with S. atra refer to comparative remarks under that species. Siphonaria hienghenensis sp. nov. has a larger, taller, paler shell with a more prominent siphonal ridge and centralised apex, a larger AO, shorter ED and a smaller BC. Siphonaria monticulus has taller shell with slightly more raised and even ribbing, paler interior, a larger AO and a longer ED. Siphonaria namukaensis sp. nov. has a paler shell with more central apex, more prominent siphonal ridge, paler golden spatula, a larger AO and a smaller BC. Siphonaria caledonica sp. nov. has a taller shell with interstice markings, a darker interior, a larger AO and ED, and a smaller BC. Siphonaria bourailensis sp. nov. has a taller, paler shell with more prominent raised ribbing, stronger edge scalloping, a larger AO, and a smaller BC. Siphonaria poindimiensis sp. nov. has a taller shell with more prominent raised ribbing, stronger edge scalloping, a larger AO and ED, and a smaller BC. Siphonaria vudaensis sp. nov. has a larger shell with narrower ribbing, a more prominent and flared siphonal ridge, stronger edge scalloping, a larger AO, and a smaller BC. Three congeners are sympatric in Guam. Siphonaria guamensis has a slightly darker shell with finer and raised ribbing, paler margin, and darker spatula, a longer AO and ED, a smaller BC, and a longer SPM. Siphonaria lirata has a shell with finer raised ribbing, a larger AO, broader ED, and a smaller BC. Siphonaria tanguissonensis sp. nov. has a slightly darker shell with finer and raised ribbing, paler margin, and darker spatula, a smaller BC, shorter BD, and longer SPM,

Four congeners are sympatric in PNG.For comparison with S. javanica refer to comparative remarks under that species. Siphonaria madangensis sp. nov. has a smaller shell with more raised ribbing and stronger edge scalloping, a smaller, less prominent AO, smaller ED, larger BC, longer narrower BD, and a very similar but shorter SPM. Siphonaria recurva sp. nov. has a darker shell with more prominent white ribbing and weaker edge scalloping, a larger AO and BC, and longer ED and F1. Siphonaria viridis has a taller shell with dark patterning and distinct dual siphonal ridge, a larger AO, smaller BC, and longer SPM.

Seven congeners occur sympatrically throughout Australia. Siphonaria costellata has a browner shell with more raised ribbing, prominent siphonal ridge, a longer BD, and longer SPM. Siphonaria gemina sp. nov. has a slightly taller darker shell with more raised ribbing, stronger edge scalloping, a smaller BC, and shorter BD. Siphonaria jiigurruensis sp. nov. has a taller darker shell with more prominent primary ribbing, red-brown patterning, a larger AO, smaller BC, longer and broader ED, and a longer SPM. Siphonaria oblia has a far smaller, darker, browner, and more fragile shell with unraised ribbing, apex strongly offset, a smaller AO, BD without distal loop, and larger ED and BC ( Jenkins 2018: 278, fig. 3C–D). Siphonaria opposita has a larger, lower shell with more prominent and flared siphonal ridge, central apex, stronger edge scalloping, a larger AO and ED. Siphonaria scabra has a larger, darker shell, greater raised ribbing, more prominent siphonal ridge, a larger AO, and a longer SPM. Siphonaria alba is sympatric in Singapore. It has a larger, darker shell with more prominent siphonal ridge, stronger edge scalloping, a larger AO, longer ED, and a longer SPM.

Siphonaria normalis has a very wide distribution spanning from the northern to the southern Tropical Pacific ( Fig. 25 ). We have not found any discontinuities in the ranges of anatomical, morphological, or mitochondrial variation that may suggest that this species as currently delineated may represent a species complex.

The SPM of S. normalis resembles that of S. radiata and S. gemina sp. nov. Hubendick (1946: 30–32, 63) considered Parellsiphon soranus from Townsville, N Qld (= S. normalis ) as of questionable status and possible synonym of S. acmaeoides for the ‘considerable resemblance’ in shell characters. Figured specimens of S. normalis in Hubendick (1947b: 2, fig 3b–i, 4b–i) appear to be a mixture of S. normalis (figs 3a–d, i) and S. waikoloaensis sp. nov. (figs 3f–h). The RS figured by Hubendick (1947b: 2, fig 5) closely matches that of S. waikoloaensis sp. nov. Figured specimens of ‘ S. normalis ’ from Oahu, Hawaii in Hubendick (1947b: 2, fig 3a–I, 4a–i) closely match S. normalis rather than S. mauiensis sp. nov. (finer ribbing, dark interior), S. nuttallii (usually paler interior, ribbing different), S. undans sp. nov. (distinct ribbing) or S. waikoloaensis sp. nov. (distinct ribbing). While Hubendick (1947b: 2) stated that the specimen depicted in figs 3a, 4a ‘except for its size, agrees with S. nuttalli [ sic nuttallii ]’. However, it differs from types of S. nuttallii . The figured specimen of ‘ S. cf normalis ’ in Maes (1967: 154, pl. 14, fig. L, from CKI) is a specimen of S. gemina sp. nov. The figured specimen of ‘ S. normalis ’ from Lomalagi, Fiji in Cernohorsky (1972: 210, pl. 60, fig. 2) matches S. normalis depicted herein. The figured specimen of ‘ S. normalis ’ in Kay (1979: 493, figs 157I–J) is a misidentification of S. nuttallii . The figured specimens of ‘unit 14’ in Dayrat et al. (2014: figs 3P, 5Q, 3R, 3S) closely resemble S. normalis as delineated herein.

Distribution and habitat. Widespread through tropical Pacific Ocean, including Society Islands, Gambier Islands, Marquesas, Hawaii, Nauru to Guam, American Samoa, Santa Cruz Islands, Solomon Islands, NC, PNG, northern Australia (Cape York through to Broome, Kimberley, WA), and Timor-Leste. In the Indian Ocean recorded from Praslin Island, Seychelles ( Ossenbrügger et al. 2023). In this study found to be rather common in sheltered positions on exposed rocky shores at upper littoral levels in Australia, Fiji, New Caledonia, Hawaii, and Guam ( Fig. 25 ).

Figures

FIGURE 1. Maximum Likelihood phylogram based on analyses of a concatenated sequence data set of 16S and COI. Branches are collapsed at the species level. Branch labels give unit numbers and accepted species names. Numbers on branches indicate branch support employing 10,000 ultrafast bootstraps.Available genus-group names are shown next to their type species. Scale bar indicating modelled sequence divergence.

FIGURE 4. Maximum Likelihood phylogram (partial, species not collapsed). Clades C–F (normalis, lateralis and pectinata groups) of the tree shown in Fig. 1. Branch labels give specimen identifiers for new sequences or Genbank accession numbers for imported sequences from other studies and geographic regions (see Tables S1–S2 for details). Identical haplotypes are merged into single tips. Numbers on branches indicate branch support by employing 10,000 ultrafast bootstraps. Clade names give unit numbers and accepted species names. Scale bar indicating modelled sequence divergence.

FIGURE 25. Known occurrence records of S. viridis, S. normalis, S. radians, S. scabra, S. funiculata, S. kurracheensis and S. carbo.

FIGURE 31. Shells of S. normalis, S. radians and S. scabra. A–I, O, S–U. S. normalis, A. Hawaii, syntype USNM 15346. B. Maui, TS, AM C.585929 [M296, SK240]. C. Oahu, TS, AM C.585930 [SK209]. D. Probable holotype of P. soranus AM C.103709. E. Qld, Townsville, TS of P. soranus AM C.585932 [SK075]. F. Qld, Cape York Peninsula, AM C.584792 [M180]. G. Marquesas, Fatu Hiva, IM-2013-74897 [M570]. H. PNG, Riwo waters, IM-2013-15250 [M555]. I. PNG, Wonad Is, IM-2013-15280 [M563]. O. Probable paratype of P. soranus MV F13840, S. Protoconch, Maui, AM C.584892 [SK212]. T. Protoconch, Qld, Cape York, AM C.585178 [SK195]. U. Hawaii, in situ. J–K. S. radians. J. Indonesia, Riau Islands, Neotype ZRC.MOL.24912 [M519]. K. Malaysia, ZRC.MOL.24894 [M594, SK526]. L–N, P–R, V–W. S. scabra. L. Lectotype NHMUK 1981011/1. M. NSW, Sydney Harbour, TS, AM C.585061 [M152]. N. AM C.585114 [M154]. P–R. Paralectotypes NHMUK 1981011/2-4. V. NSW, in situ. W. Protoconch, AM C.585062 [SK169]. Unlabelled scale bars = 10 mm.

FIGURE 32. Reproductive morphology of S. normalis and S. scabra. A–D. S. normalis A–B. Hawaii, Oahu, TS, AM C.585930 [SK209]. C. Guam, Umatac Bay, AM C.584872 [M346, SK142]. D. Hawaii, Maui, TS, AM C.585929 [M296, SK240]. E–F. S. scabra, NSW, Sydney Harbour, TS, AM C.585114 [M154, SK236]. Scale bars = 1 mm.