Conus (Splinoconus) hamamotoi Yoshiba & Koyama, 1984

Tenorio, Manuel J. & Puillandre, Nicolas, 2023, Revision of the deep-water cone snail fauna from New Caledonia (Gastropoda, Conoidea), European Journal of Taxonomy 896, pp. 1-134 : 103-105

Conus (Splinoconus) hamamotoi Yoshiba & Koyama, 1984

Figs 2 , 77–78

Conus hamamotoi Yoshiba & Koyama, 1984: 115 , pl. 1 figs 1–5.

Conus hamamotoi – R̂ckel et al. 1995b: no. 35, pl. 9 figs 23–27.

Nitidoconus hamamotoi – Tucker & Tenorio 2013: 218.

Kioconus (Isoconus) hamamotoi – Monnier et al. 2018a: 544.

Material examined

15 lots (19 specimens). See Supp. file 1.

Type material

Holotype JAPAN • 23 mm; 1 to 1.5 km W of Ogokuda Beach , Wakayama Prefecture; 60–70 m depth; WPMNH ( Fig. 77A ).

Figured material

NEW CALEDONIA • 12.1 mm; Lansdowne‒Fairway, off New Caledonia, stn DW02; 20º50′ S, 161º37′ E; 62 m depth; 20 Jul. 1988; CORAIL 2 expedition; MNHN ( Fig. 77B ) • 18.1 mm; Plateau des Chesterfield , off New Caledonia, stn DW108; 19º09′ S, 158º49′ E; 68 m depth; 27 Jul. 1988; CORAIL 2 expedition; MNHN ( Fig. 77C, L–M ) • 14.8; Plateau des Chesterfield , off New Caledonia, stn DW141; 19º34′ S, 158º27′ E; 95 m depth; 30 Jul. 1988; CORAIL 2 expedition; MNHN ( Fig. 77D ) • 26.8 mm; Plateau des Chesterfield , off New Caledonia, stn DW108; 19º09′ S, 158º49′ E; 68 m depth; 27 Jul. 1988; CORAIL 2 expedition; MNHN ( Fig. 77E ) • 15.3 mm; W Bellona, off New Caledonia, stn DW2547; 21º06′ S, 158º36′ E; 356‒438 m depth; 11 Oct. 2005; EBISCO expedition; MNHN ( Fig. 77F ) • 14 mm; Banc Ellet, off New Caledonia, stn DW3865; 22°53′ S, 169°26′ E; 100‒280 m depth; 16 Sep. 2011; EXBODI expedition; MNHN ( Fig. 77G ) • 15.1 mm; Norfolk Ridge, Munida, off New Caledonia, stn DW3109; 23°01′ S, 168°18′ E; 150‒180 m depth; 28 Oct. 2008; TERRASSES expedition; MNHN ( Fig. 77H ) • 12.8 mm; Norfolk Ridge, off New Caledonia, stn DW186; 23º25′ S, 168º06′ E; 57‒59 m depth; 31 Jan. 1993; SMIB 8 expedition; MNHN ( Fig. 77I ) • 13.7 mm; same collection data as for preceding; MNHN ( Fig. 77J ) • 11.8 mm; same collection data as for preceding; MNHN ( Fig. 77K ) .

Geographical distribution and bathymetry

Southern Japan and New Caledonia, where it has been sampled in Norfolk Ridge, Loyalty Ridge and the Coral Sea, at depths between 0 to 400 m, typically subtidal to 200 m deep.

Remarks

Shell small (maximum shell length 27 mm). Broadly conical, with a tuberculate shoulder and a spire of moderate height and straight outline. Multispiral protoconch ( Fig. 77L ) of about 3 whorls. Last whorl with spiral ribs and ribbons, which may be granulose ( Fig. 77E, H ), colored with pink to orange leaving a mid-body irregular spiral band with reddish brown dots arranged in spiral rows. Radular tooth ( Fig. 77M ) with the anterior section slightly longer than the posterior section. Tooth serrated with 15–16 denticles in one row, ending on an almost indistinct rounded cusp. Barb small. Blade rounded, covering about 70% of the anterior section of the tooth. Small basal spur present on top of the rounded base. Conus (S.) hamamotoi is not a typical deep-water cone snail, as it is commonly found above a depth of 100 m. However, live specimens have been found in New Caledonia at depths between 150 and 180 m ( Fig. 77H ). Dead specimens have been found down to 400 m deep. This is a rare species, which has been now examined using DNA, and its radula studied. In the phylogeny ( Fig. 2 ) this species appears sister to C. (S.) capitanellus , also in the Splinoconus clade.

Figures

Fig. 2. Cox1-based Bayesian phylogeny. Posterior probabilities (> 0.95) and bootstrap values (> 90) from the ML analysis are provided for each node. Intraspecific relationships are collapsed. Subgenus names are indicated on the right.

Fig. 77. Conus (Splinoconus) hamamotoi Yoshiba & Koyama, 1984. A. Holotype, 1-1.5 km west of Ogokuda beach, Wakayama prefecture, Japan, 60‒70 m depth, 23 mm (WPMNH). B. Lansdowne‒ Fairway, Coral Sea, 62 m depth, 12.1 mm. C. Plateau des Chesterfield, Coral Sea, 68 m depth, 18.1 mm. D. Plateau des Chesterfield, Coral Sea, 95 m depth, 14.8 mm. E. Same collection data as for specimen C, 26.8 mm. F. W Bellona, Coral Sea, 356‒438 m depth, 15.3 mm. G. Banc Ellet, off New Caledonia, 100‒280 m depth, 14 mm. H. Banc Munida, Norfolk Ridge, 150‒180 m depth, 15.1 mm. I. Norfolk Ridge, 57‒59m depth, 12.8 mm. J. Same collection data as for specimen I, 13.7 mm. K. Same collection data as for specimen I, 11.8 mm. L. Protoconch of specimen C. M. Radular tooth of specimen C. Scale bars = 10 mm, unless otherwise stated.

Fig. 78. Bathymetric range and distribution map for Conus (Splinoconus) hamamotoi Yoshiba & Koyama, 1984. Red circles indicate the points where the species was collected.