Siphonaria vudaensis, B. W. Jenkins & Köhler, 2024

Siphonaria vudaensis View in CoL sp. nov.

( Figs 79A–C, K–L, M View FIGURE 79 , 80A–B View FIGURE 80 )

Siphonaria atra View in CoL — Cernohorsky 1972: 210, pl. 60, fig. 1 (not Siphonaria atra Quoy & Gaimard, 1833 View in CoL ).

Siphonaria ‘ atra View in CoL group, unit 37’— Dayrat et al. 2014: 264, fig. 5S.

Material examined. Type material. Holotype, from Heal of foot , First Landing , near Vuda Point 17°40.753’S, 177°23.006’E, Viti Levu, Fiji; coll. B.W. Jenkins, FI03-1, 25 Aug 2018 ( AM C.584785 [SK119 (RS and SPM], Fig. 79A View FIGURE 79 ). GoogleMaps Paratypes, same data as holotype ( AM C.585523 21p, C.584859 p [M288], C.584860 p [M289], Fig. 79B, C.584861 View FIGURE 79 p [M291]; C.584862 p [M292], Fig. 79C View FIGURE 79 ). GoogleMaps

Other, non-type material. Fiji, Viti Vevu: Heal of foot First Landing , 17°40.753’S, 177°23.006’E FI03-1 ( AM C.584863 p [SK122], C.584995 p [SK121]); GoogleMaps Vuda Point Marina seawall, 17°40.878’S, 177°23.009’E, FI03- 2 ( AM C.585324 p) GoogleMaps .

External morphology ( Fig. 79K View FIGURE 79 ). Foot sole and foot wall evenly cream, paler to foot edge; uneven black pigmented blotches on foot wall; cephalic folds thick narrow; black pigmentation darker over centre of cephalic folds, paler to foot; mantle wide thin with heavy broad lobes, edge thickened with black pigmentation aligning with rib interstices; pneumostome small, under mantle.

Shell ( Figs 79A–C, J, L View FIGURE 79 ; Table S9). Medium to large sized (max sl mean = 22.5 mm, SD = 3.3 mm, n = 5), ovate; low, profile very flat; apex offset slightly posterior and left, apical sides convex; shell whorl dextral, protoconch direction homostrophic (n = 1, Fig. 79L View FIGURE 79 ); growth striae apparent, shell thin; rib count (mean = 44.6, SD = 10.4, n = 5), fairly even number of primary and secondary ribs, 14–15 primary ribs pale white, fairly straight often bent, slightly raised, protrude 1–2 mm beyond shell lip to unevenly scallop a flat edge; siphonal ridge formed by 3 close primary ribs shows greatest extension beyond lip; 1–2 secondary ribs between primary, rib interstices white at apex to dark brown black at shell edge. Interior shell margin dark brown with pearly lustre, fine white rays extend over shell margin to spatula aligning under primary/secondary ribs, siphonal groove distinct, slightly curved to lateral; spatula dark chocolate brown to mottled white;ADM scar distinct, darker than margin, same colour as spatula; CMS concave, paler than shell lip; thickening of shell lip occurs, translucent pearly thickening rather than over covering pigmentation or whitening; juvenile specimens thin often translucent; small specimens evenly dark chocolate brown.

Reproductive system ( Fig. 80A; n View FIGURE 80 = 1). Positioned within coelom under the respiratory cavity, hermaphroditic complex ( HG, AG and MG) positioned to posterior against right foot wall and over foot sole, epiphallic parts positioned to anterior firmly between BM and RAM. AO very large, elongated, centrally bent, bluntly bulbous, joins to upper part of prominent GA, singular GP; ED relatively short, broad, shorter than AO, joins to side of GA; GA, AO, ED all white muscular fibrous tissue; EG soft whitish, slightly folded, smaller than AO; single short blunt twisted flagellum (F1); BD and CD jointly but opposing connections to GA between ED, AO and GP; BD long narrow, with distinct folds prior to GA connection and prominent distal loop with MA to inner body wall; CD broad short, wider than BD; both ducts smooth and pass closely together through RAM ( BD over CD); CD connects into MG; BD loops prior to connection to small bulbous BC with thin translucent test, embedded in folds of MG / AG close to embedded SV; HD short, thick, coiled, links AG to smaller yellowish granulated HD; MG and AG folded, soft white tissue.

Spermatophore ( Fig. 80B View FIGURE 80 ). Thread-like, relatively long (length = 11.4 mm) and thin, translucent, over half-length comprises a translucent cylindrical body section (head length = 7.2 mm, ~63% of SPM length) containing a white gelatinous thread-like core, tapers rapidly into a filamentous transparent flagellum; head section much thicker than flagellum (head width = 133 μm, flagellum width = 13.1 μm); head tip tapered bluntly rounded, both sections smooth, featureless; 2 SPM coiled, embedded in red-brown gelatinous mass [SK119].

Comparative remarks. In our mitochondrial phylogeny ( Figs 1 View FIGURE 1 , 2 View FIGURE 2 ), S. vudaensis sp. nov. ( atra group, unit 37) is the sister species of a clade containing two species, S. tenebrae sp. nov. (unit 92) and S. subatra (unit 38). Siphonaria vudaensis differs from these two species by COI distances of ≥ 10.9% ( S. tenebrae ) and ≥ 13.3% ( S. subatra ) (Table S3).

We found this species in sympatry with three congeners on Viti Levu: For comparisons with S. namukaensis sp. nov., S. normalis , and S. tagaqaensis sp. nov. refer to comparative remarks under these species. Specimens from Tuituila, Samoa and Viti Levu figured as ‘unit 37, atra group’ in Dayrat et al. (2014: figs 5P, Q) belong to this species. The specimen figured as ‘ S. atra ’ in Cernohorsky (1972: 210, pl. 60, fig. 1) is a specimen of S. vudaensis sp. nov.

Distribution and habitat. Recorded from Viti Levu, Fiji and Tutuila, American Samoa ( Fig. 78 View FIGURE 78 ). In this study, found in sheltered positions on moderately exposed rocky boulder shores, at mid littoral level.

Etymology. For the type locality, Vuda Point, Viti Levu, Fiji.