Siphonaria camura, Jenkins, Bruce & Köhler, Frank, 2024

Siphonaria camura View in CoL sp. nov.

( Figs 53E–F View FIGURE 53 , 54D–E, O–P View FIGURE 54 )

Material examined. Type material. Holotype, from Tancha Bay , 26°27.897’N, 127°49.131’E, Okinawa, Japan; coll. B.W. Jenkins, JP01-5, 20 March 2020 ( AM C.585614 [M491, SK310]) GoogleMaps . Paratype, same data as holotype ( AM C.585195 p [SK331]); GoogleMaps paratype from Tancha Bay point, 26°27.941’N, 127°49.194’E, Okinawa, Japan; coll. B.W. Jenkins, JP01-6, 20 March 2020 ( AM C.584920 p [M490, SK309]); GoogleMaps 5 paratypes from Moon Bay , Onna, Okinawa; coll. B.W. Jenkins, JP01-4, 18 March, 2020 ( AM C.585621 5p) GoogleMaps .

Other, non-type material. Japan, Okinawa: Sun Marina Beach, seawall, 26°27.842’N, 127°48.755’E, JP01-1 ( AM C.585617 8p); GoogleMaps Tancha Bay 1, 26°27.897’N, 127°49.131’E, JP01-5 ( AM C.585951 5p, C.585195 p [SK331]); GoogleMaps Tancha Bay 2, 26°27.941’N, 127°49.194’E, JP01-6 ( AM C.585950, 4p, C.585613 p [SK510]) GoogleMaps . China, Hong Kong: Repulse Bay 22°14.1’N, 114°11.71’E ( ZRC. MOL.24899 p) GoogleMaps .

External morphology ( Fig. 54P View FIGURE 54 ). Foot sole dark yellowish/grey, paler to foot edge; foot wall, mantle, cephalic folds and pneumostomal lobe all evenly dark yellowish/green in colour; mantle thin, translucent, narrower than foot wall, weakly lobed with a thickened yellow banded edge; faint irregular black blotches of pigmentation on foot wall and cephalic lobes;pneumostome fold long between right ADMs and within mantle.

Shell ( Figs 54D–E View FIGURE 54 ; Table S9). Small sized (max sl mean = 11.6 mm, SD = 0.9 mm, n = 8), ovate, height tall; shell thin, apex offset strongly posterior and central; apical sides convex, strongly concave at posterior; protoconch direction homostrophic (n=2; Fig. 54P View FIGURE 54 ), peaked, hooked to posterior, shell whorl dextral; growth striae uneven; rib count (mean = 35, SD = 0.7, n = 8), exterior unevenly brown, weak radial banding, protoconch area dark brown, paler to shell edge; ribs uneven, increasingly broader and align to uneven fragile and corrugated shell edge, periostracum freely extending; rib interstices darker; siphonal ridge prominent formed by paired primary ribs. Interior shell margin and spatula evenly dark chocolate brown, white rays on shell lip align under rib ends, fade to margin; siphonal groove distinct, same colour as shell margin; ADM scar distinct, CMS straight, indistinct; thickening of shell lip not observed.

Reproductive system ( Fig. 53E; n View FIGURE 53 = 3): positioned within coelom under the respiratory cavity, hermaphroditic glands positioned to posterior against right foot wall and over foot sole, epiphallic parts positioned over BM, BC directly lodged in soft white folds of MG, BD not through RAM as with CD (n = 2, Fig. 53E View FIGURE 53 ); AO small, elongated, narrow, bluntly pointed; ED broad, elongated, centrally twisted, longer than BD; ED (with outer MA) and AO each enter into top of small GA; EG relatively large with folds, often elongated; single, short, broad flagellum F1 with curled end, appears as a right-angled protrusion from end of ED at join with EG; AO, GA and ED all muscular white tissue; BD and CD join GA with swollen opposing connections close to entry of ED and AO; CD passes between inner foot wall and outside RAM connecting into large MG; BD without distal loop, longer and narrower than CD, enters MA alongside or behind ED, both ducts broad smooth; BC large, club shaped, translucent test; HD large, coiled, links soft white folds of AG to similar sized brownish finely granulated HG; SV embedded within AG, outer sides of AG and HG match curvature of inner foot wall at right posterior quarter of coelom.

Spermatophore ( Fig. 53F View FIGURE 53 ). Body cylindrical, thread-like (length = 10.9 ± 3.0 mm, n = 2), test thin, translucent, smooth; head tip bluntly rounded, section containing a white gelatinous core tapers to a thinner flagellum; head section longer thicker than flagellum (head length = 6.0 ± 0.96 mm, n = 2; ~54% of SPM length, flagellum length = 4.8 ± 2.1 mm, head width = 120 ± 0 μm, flagellum width = 50 ± 0 μm, n = 2), outer ridge of mid flagellum possesses 35-17+ evenly spaced barbs pointing towards head; 2 SPM tightly coiled in white gelatinous mass in each BC of two specimens ( AM C.584920, AM C.585614).

Comparative remarks. In our mitochondrial phylogeny, S. camura sp. nov. (unit 84) is the sister species of S. japonica (unit 2); both species together forming a distinctive subclade in the Siphonaria tree ( Figs 1 View FIGURE 1 , 4 View FIGURE 4 ). Both species differ form each other by COI distances of ≥ 11% (Table S2). Throughout its range, this species has been found in sympatry with five congeners: For comparisons with S. japonica , S. subatra , S. sipho , and S. rucuana refer to comparative remarks under these species. Siphonaria tanchaensis sp. nov. has a larger, taller, paler shell with greater edge scalloping, a white/brown interior and golden-brown spatula, a larger AO, longer narrower BD distal loop, smaller BC, and a longer F1.

Distribution and habitat. Recorded from Okinawa, Japan and Repulse Bay, Hong Kong ( Fig. 55 View FIGURE 55 ). In this study, found on exposed rocky shores in sheltered positions, such as rock crevices, hollows and amongst oysters, mid to upper littoral levels ( Fig. 54O View FIGURE 54 ).

Etymology. From ‘camur’ (Latin = curved, bent), referring to the slightly curved, upturned end of the siphonal ridge at the shell lip.