Siphonaria nuttallii Hanley, 1858

Siphonaria nuttallii Hanley, 1858 View in CoL

( Figs 39I–J View FIGURE 39 , 40K–N, S, U–V View FIGURE 40 )

Siphonaria nuttallii Hanley 1858b: 153 View in CoL (type locality: ‘littora insularum sandvicensium’ [coast of the Hawaiian Islands]).— Paetel 1875: 92; Coan & Kabat 2012: 336; White & Dayrat 2012: 66; Dayrat et al. 2014: 266.

Siphonaria nuttalli — Paetel 1873: 117; 1883: 178; 1889: 429; Pilsbry 1920b: 379; Christiaens 1980a: 79 (incorrect subsequent spelling of nuttallii View in CoL ).

Siphonaria normalis View in CoL forma chirura Pilsbry 1920b: 380 View in CoL , fig. 15 (type locality: Hawaii).— Edmondson 1946: 188, fig. 102b.

Siphonaria (Siphonaria) nuttalli — Hubendick 1945: 73; 1946: 17, 50, 51–52, 63, pl. 4, fig. 1–4 (incorrect subsequent spelling of nuttallii View in CoL ).

Siphonaria chirura View in CoL — Baker 1964: 159; White & Dayrat 2012: 61.

Siphonaria normalis View in CoL — Kay 1979: 493, figs 157I–J.

Material examined. Type material. Lectotype of Siphonaria nuttallii Hanley, 1858b , present designation, from Hawaii ( NHMUK 20120166/1 , Fig. 40K View FIGURE 40 ). Four paralectotypes, same data as lectotype ( NHMUK 20120166/2-5 , Fig. 40N View FIGURE 40 ).

Three syntypes of Siphonaria normalis forma chirura Pilsbry, 1921 from Kahoolawe , Hawaii [ USA]; coll. H. A. Pilsbry, 1913 ( ANSP 281800a ; ‘lectotype’, refer Taxonomic remarks).

Other, non-type material. Hawaii; Maui: Ho’okipa Beach , 20°56.029’N, 156°21.411’W HA03-4 ( AM C.585444 11p, C.585661 3p form chirura , C.584894 p [M470, protoconch G7], C.584895 p [M471, SK273, form chirura ], C.584896 p [M472, SK079], C.584897 p [M486, SK305, form chirura ], C.584898 p [SK211]). GoogleMaps

Taxonomic remarks. The largest syntype of S. nuttallii is herein designated as the lectotype ( Fig. 40K View FIGURE 40 ) for the stabilisation of the name (Art. 74.1 of the Code). Our delineation of this species is based on comparative analyses of the morpho-anatomy and mitochondrial genetics of freshly collected topotypes ( Fig. 40L View FIGURE 40 ) and S. normalis var. chirura ( Fig. 40M View FIGURE 40 ) and geographic series of additional specimens (Table S1). We establish S. normalis var. chirura as a new junior synonym. The designation of lectotype for S. chirura by Baker (1964: 159 ‘ANSP TSD now: 281800a’) is invalid as it is not based on a syntype (Art. 74.1 of the Code). The specimen is badly worn. Pilsbry (1920b: 379) and Cernohorsky (1972: 210) erroneously treated S. nuttallii as a synonym of S. normalis .

External morphology. Foot sole, foot wall, mantle, cephalic folds, pneumostomal lobe evenly grey/green, paler to foot edge; irregular black blotches of pigmentation on foot wall and concentrated over centre cephalic folds; mantle thin, translucent narrower than foot wall, covers exposed inner shell lip, wider at anterior, mantle edge thickened, dark edge band, weakly lobed with even black pigmentation rays aligned with underside of shell rib interstices; genital pore indistinct; small black epithelial eye spot centralised on each of centrally touching cephalic folds; pneumostomal lobe long broad under mantle between the right anterior and right posterior ADMs.

Shell ( Figs 40K–N, S View FIGURE 40 ; Table S9). Small sized (max sl mean = 12.7 mm, SD = 1.9 mm, n = 9), circular ovate; height medium; apex offset weakly posterior and laterally central, apical sides convex to straight; protoconch direction homostrophic to central (n = 3; Fig. 40S View FIGURE 40 ), shell whorl dextral; growth striae prominent in bands, shell thickness thick; rib count (mean = 42, SD = 2, n = 9); exterior uneven with faint radial banding; primary ribs pale tan, fairly straight to wavy, broaden and weakly raised to shell edge, ridges and ends rounded, protrude beyond shell edge; edge finely scalloped and unevenly corrugated; 2–5 finer secondary ribs between primary ribs, rib interstices darker brown with white patches; siphonal ridge formed by paired primary ribs; Interior shell margin white rays under primary ribs, dark brown rays under rib interstices, rays extend from shell lip over shell margin fading to spatula; siphonal groove indistinct, paler than shell margin; spatula mottled dark brown to white; ADM scar distinct, dark brown, CMS convex; no thickening or whitening of shell lip observed.

Reproductive system ( Fig. 39I; n View FIGURE 39 = 4). 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 large, elongate, broad, bluntly pointed, slightly bent centrally, joins to top of GA in conjunction with relatively short, strongly twisted, very broad ED; EG large white folded, single long narrow looped flagellum F1 appears as an extension of ED at join with EG; AO, GA and ED all muscular white tissue; BD and CD connect closely in opposite directions into GA between connections of ED and AO, both ducts narrow smooth featureless, pass together through RAM connecting into MG, BD above and longer than CD, with distal loop and MA to inner foot wall; BC medium in size, spherical, embedded in folds of MG, test translucent; SV embedded in AG; HD reasonably long, thick coils, brown markings, 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 ( Fig. 39J View FIGURE 39 ). Body cylindrical, thread-like (length = 6.7 mm, n = 1), test thin, translucent; head tip tapered bluntly rounded, section containing a white gelatinous core, tapers to a thin flagellum and tip; both sections smooth, featureless; head longer, thicker than flagellum (head length = 5.1 mm; 76% of SPM length; flagellum length = 1.6 mm; head width = 95 μm; flagellum width = 16 μm), 2 SPM tightly coiled in white gelatinous mass in one BC [M471].

Comparative remarks. Siphonaria nuttallii ( plicata group, unit 85; Figs 1 View FIGURE 1 , 2 View FIGURE 2 ) differs from other species by COI distances of ≥ 20% (Table S7). Siphonaria nuttallii occurs in sympatry with S. normalis at Big Island, Hawaii; refer to comparative remarks under that species. Siphonaria nuttallii has a similar shell morphology like other members of the plicata group, such as S. mauiensis sp. nov. (also occurring on Maui, but not found in immediate sympatry), S. plicata , S. tongatapuensis sp. nov. (both from Tonga), S. monticulus (from Lifou), S. namukaensis sp. nov. ( Fiji and NC) and S. poindimiensis sp. nov. However, all these species are genetically well-differentiated. Specimens figured by Hubendick (1946: 91, pl. 4, figs 1–4) as S. nuttallii and S. chirura by Edmondson (1946: 188, figs 102b) are consistent with typical characteristics of S. nuttallii as defined herein and are within the known distribution of this species. Specimens figured as ‘ S. normalis’ in Kay (1979: 493, figs 157I, J) from Hawaii are likely of S. nuttallii for closely resembling the types ( Figs 40K–N View FIGURE 40 ).

Distribution and habitat. Only known from Maui, Hawaii ( Fig. 37 View FIGURE 37 ), found on moderately exposed rocky shores in sheltered positions, mid littoral level ( Fig. 40U View FIGURE 40 ).