Siphonaria kudatensis, 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 : 159-160

Siphonaria kudatensis sp. nov.

( Figs 61H, 62D)

Material examined. Type material. Holotype, from Bak Bak Beach , Kudat, Sabah, 07°00′ N, 116°46′ E, E Malaysia; coll. P.H. Colman, 31 March, 1984, HWL on rocks on beach ( AM C.585938 [SK522], Fig. 61H).

External morphology (preserved). Foot sole, foot wall, cephalic folds and pneumostome evenly cream, paler to foot edge; mantle edge thickened strongly lobed without darker pigmentation on mantle edge or cephalic folds.

Shell ( Fig. 61H; Table S9). Small sized (max sl = 12.8 mm, n = 1), circular ovate, height tall; apex weakly offset to posterior and centrally left, apical sides weakly convex except posterior which is straight; protoconch direction heterostrophic (n = 1), shell whorl dextral; growth striae clear; exterior pale brown, radial colour bands indistinct; rib count (38, n = 1), primary ribs fewer than secondary, very prominent, strongly raised, off white and rounded, broaden to shell edge; paired primary ribs form siphonal ridge, ribs ends protrude weakly at shell lip, shell edge weakly scalloped and corrugated, few secondary ribs, rib interstices indistinct, darker. Interior shell margin to spatula mottled dark chocolate brown; outer shell margin paler with white rays aligning under ribs; siphonal groove distinct, same colour as spatula, darker than margin; ADM scar indistinct, CMS convex; no thickening of shell lip noted.

Reproductive system ( Fig. 62D; n = 1). Positioned within right side of coelom, against foot wall on foot muscle, under the respiratory cavity; epiphallic parts positioned between RAM and BM. GA small, with singular GP through foot wall; AO large, elongated, broad, tip bluntly pointed, weakly centrally bent, merges to upper part of GA, singular GP; ED long, wide, upper twist, shorter than AO, joins to lower side of GA; GA, AO, ED all white muscular fibrous tissue; EG soft whitish, folded; twisted narrow flagellum (F1) lays over MG, possible second shorter flagellum (F2); BD and CD join closely but with opposing connections to side of GA between AO and GP; both ducts long, featureless, smooth and pass outside RAM ( BD over CD); BD with prominent short distal loop and MA attached to inner body wall, connected to small sized bulbous BC with thin translucent test, positioned in folds of AG; CD connects into soft white folded tissues of small MG / AG complex; BC relatively small, elongate, thin whitish translucent test, embedded in MG / AG folds close to large embedded SV; outer edge of MG lobed; HD large, coiled, links ducts in soft white folded tissues of AG to yellowish finely granulated HG; AG larger than HG, sides match curvature of inner foot wall.

Comparative remarks. We have found S. kudatensis sp. nov. ( laciniosa group) in sympatry with two congeners at Kudat, Sabah. Siphonaria radiata has a lower, broader shell with a less offset apex, less prominent ribbing and siphonal ridge, a smaller AO, shorter BD without a distal loop and a larger BC. Siphonaria radians has a lower, broader shell with a less offset apex, finer ribbing and a less prominent siphonal ridge, a smaller AO, AG and HD, larger HG, and a longer F1. We have been unable to sequence mtDNA markers from specimens of this species.

Distribution and habitat. Recorded exclusive from Sabah, Malaysia ( Fig. 60). Found on rocky shores, intertidal.

Etymology. Named after the type locality of Kadat, Sabah, E Malaysia.