Siphonaria recurva, sp. nov.
Creators: name: Jenkins, Bruce
name: Köhler, Frank
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Siphonariida
Siphonariidae
Siphonaria
Siphonaria recurva

description: Siphonaria recurva sp. nov.
(Figs 71C, 72A)
Siphonaria ‘ atra group, unit 32’— Dayrat et al. 2014: 264, fig. 5I.
Material examined. Type material. Holotype, from NW side of Big Nusa Is., 02°34.1’S, 150°46.7’E, New Ireland, PNG; coll. KAVIENG 2014 expedition, KM21, 28 Jun. 2014 (MNHN IM-2013-55336 [M534], Fig. 71C).
External morphology (preserved). Animal exterior evenly cream, foot sole darker, paler to foot edge; irregular black pigmentation on foot wall.
Shell (Fig. 71C; Table S9). Small sized (max sl = 15.3 mm, n = 1), circular ovate, height tall; apex noticeably offset to posterior and left, hooked to posterior, apical sides convex, posterior straightening, protoconch direction homostrophic (n = 1, MNHN IM-2013-55336 holotype), shell whorl dextral, shell thin; growth striae prominent and slightly raised; multiple radial colour bands, protoconch area dark brown, central band pale, shell fringe dark brown; rib count (35, n = 1), primary ribs far more prominent than secondary ribs; ~ 17 pale brown to off white primary ribs, ridges raised and rounded, broaden to shell edge; paired primary ribs form siphonal ridge, most primary ribs protrude strongly beyond shell lip with ends slightly raised to strongly scallop and corrugate shell edge; 0–3 finer secondary ribs between primary ribs, rib interstices darker. Interior shell margin and spatula dark chocolate brown; off white to cream rays on shell margin align under ribs, siphonal groove distinct, same colour as spatula, paler than margin; ADM scar distinct, CMS convex; no thickening of shell lip noted.
Reproductive system (Fig. 72A; n = 1). Positioned within right side of coelom, against foot wall on foot muscle, under the respiratory cavity; epiphallic parts lie over back of BM; GA medium, singular GP through foot wall; AO bulbous wide, tip blunt; ED short, wide, bent, joins to side of GA; single flagellum (F1) short, twisted, as long as ED, appears as an extension of ED; GA, AO, ED all white muscular fibrous tissue; EG small, soft whitish tissue, slightly folded; BD and CD long, narrow, jointly connect into upper end of GA; BD with distal loop and MA, longer, centrally narrower than CD but wider at GA and MG junctions; both ducts smooth featureless, pass closely together through RAM (BD over CD) into folded, soft white tissues of large MG / AG complex; BC large, bulbous, thin translucent test, embedded in MG folds close to embedded SV; HD small, lobed, coiled, links AG to small yellowish granulated HG; AG larger than HG, sides match curvature of inner foot wall.
Comparative remarks. In our mitochondrial tree (Figs 1, 2), S. recurva sp. nov. (atra group, unit 32) is the sister species of S. incerta (unit 72). Both species differ by COI distances of ≥ 16.7%. From other species S. recurva differs by distances of ≥ 23.3% (Table S3). We found S. recurva sp. nov. in sympatry with two congeners in New Ireland, PNG. For comparisons with S. nusalikensis sp. nov. and S. normalis refer to comparative remarks under these species. The specimen figured as ‘ atra group, unit 32’ in Dayrat et al. (2014: fig. 5I) is conspecific.
Distribution and habitat. Recorded from Big Nusa Island, Kavieng, New Ireland, PNG and Tutuila, American Samoa, Western Pacfic Ocean (Fig. 73). Found on intertidal platforms and limestone cliffs.
Etymology. Derived from Latin adjective “recurvus” meaning ‘curving back, crooked’ referring to the shape of the shell’s prominent protoconch.
description: Published as part of 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), pp. 1-217 in Megataxa 13 (1) on page 176, DOI: 10.11646/megataxa.13.1.1, http://zenodo.org/record/14984186