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

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 : 162

Siphonaria maloensis sp. nov.

( Figs 63C–F)

Material examined. Type material. Holotype, from N coast of Malo Is, 15°37.7’S, 167°11’E, Vanuatu; coll. Marine Biodiversity Survey, 18 Sept. 2006 VM16, sand and coral ( MNHN IM-2006-31454 p [M545] Fig. 63C) . Paratype, same data as holotype ( MNHN IM-2006- 31358 p [M546], Fig. 63D); two paratypes, from Palikulo Peninsula, 15°28.8’S, 167°15.3’E, Vanuatu; coll. Marine Biodiversity Survey, 14 Sept. 2006 VM11, hard bottom ( MNHN IM-2006-31355 p [M547], Fig. 63E; IM-2006- 31353 p [M548], Fig. 63F) .

External morphology (preserved). Foot sole, foot wall, cephalic folds and pneumostome cream, paler to foot edge; mantle translucent, edge thickened strongly lobed with dark/black pigmentation on mantle edge aligning with rib interstices, faint pigmentation over cephalic folds.

Shell ( Figs 63C–F; Table S9). Ovate, small to medium sized (max sl mean = 17.9 mm, SD = 2.3 mm, n = 4); apex offset central and weakly to left, apical sides strongly convex, height tall; protoconch direction undetermined, shell whorl dextral; exterior uneven without prominent radial colour bands; growth striae distinct, shell thickness thick; rib count (mean = 45.5, SD = 2.3, n = 4), ribs fairly even, primary ribs pale grey, wavy, slightly broaden and increasingly raised to shell edge, ridges rounded narrow; edge finely scalloped and unevenly corrugated; siphonal ridge clear, formed by 2–3 primary ribs; few finer secondary ribs, rib interstices darker grey with irregular red/brown markings; interior shell margin white, red brown rays aligned under rib interstices, from shell lip over shell margin to spatula, siphonal groove distinct, same colour as shell margin; spatula dark brown; ADM scar distinct, darker brown, CMS convex; thickening and whitening of shell lip occurs ( Fig. 63C).

Comparative remarks. In our molecular phylogeny ( Figs 1, 2), S. maloensis sp. nov. ( laciniosa group, unit 87) is the sister species of S. caledonica sp. nov. (unit 23) from New Caledonia. Both species differ from each other by 16S distances of ≥ 9.7%. Siphonaria maloensis differs from S. normalis by 16S distances of ≥ 10%. Morphologically, S. caledonica sp. nov. has a smaller, thinner, taller, darker shell, with more prominent primary ribbing, and a less scalloped edge. We found S. maloensis sp. nov. in sympatry with S. viridis in Vanuatu; refer to comparative remarks under that species.

Distribution and habitat. Recorded exclusively from Malo Island, Vanuatu, Pacific Ocean ( Fig. 67). In this study, found on hard substrate, sand and coral, intertidal.

Etymology. Named after the type locality of Malo Island, Vanuatu, Pacific Ocean.