Siphonaria caledonica, 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 : 169-170

Siphonaria caledonica sp. nov.

( Figs 65J–L, O, S–T , 66I–J )

Siphonaria ‘ laciniosa group, unit 23’— Dayrat et al. 2014: 261, fig. 4 E.

Material examined. Type material. Holotype, from Tiari , 20°15.692’S, 164°24.664’E, NC; coll. B.W. Jenkins, NC04-3, 25 Oct 2018 ( AM C.584788 [M364, SK130 (RS + SPM)], Fig. 65J ). Paratype, same data as holotype ( AM C.585838 p [M362], Fig. 65L ); seven paratypes, from Bonhomme de Bourail , La Roche Percee, 21°36.487’S, 165°27.423’E, NC; coll. B.W. Jenkins, NC06-3, 28 Oct 2018 ( AM C.584799 5p, C.585015 p [M366], Fig. 65K, C.585016 p [M367]) .

Other, non-type material. NC: Tiari, 20°15.692’S, 164°24.664’E NC04-3 ( AM C.585969 20p,AM C.584787 p [SK060], C.585839 p [M363, SK131], C.585840 p [M365], C.585841 p [M459]); Bonhomme de Bourail , La Roche Percee, 21°36.487’S, 165°27.423’E NC06-3 ( AM C.584798 15p); Presqu’ile de Ouano La Foa, 20°51.434’S, 165°48.479’E NC06-4 ( AM C.595910 12p) .

External morphology ( Fig. 65S ). Foot sole, foot wall, cephalic folds and pneumostome pale grey, paler to foot edge; mantle translucent narrow, edge thickened, weakly lobed with black pigmentation bands aligning with rib interstices; black pigmentation more intense and darkest over centre of cephalic folds.

Shell ( Figs 65J–L, T ; Table S9). medium sized (max sl mean = 17.5 mm, SD = 3.7 mm, n = 8);ovate, often elongated, shape irregular, height tall; apex offset slightly posterior and left, apical sides convex, posterior side straight to slightly concave, protoconch direction homostrophic (n = 1, Fig. 65T ), shell whorl dextral; growth striae prominent in bands, shell thick; rib count (mean = 44.4, SD = 5, n = 8), radial shading bands occur, protoconch area dark; primary ribs white, fairly straight often bent, narrow and uneven in width, ridge rounded, extend slightly beyond shell lip to scallop and corrugate the edge; ribs may be fairly evenly spaced, paired primary ribs forming siphonal ridge bounded with a wide interstice either side; 0–4 secondary ribs between primary ribs, most secondary ribs and rib interstices dark brown, smaller ribs occur in growth interstitial areas. Interior shell margin dark brown to tan, white rays align on shell margin under primary/secondary ribs, siphonal groove distinct, same colour as shell edge, points to right anterior; spatula dark chocolate brown to mottled tan even whitish; ADM scar distinct, CMS straight, paler than shell lip; thickening of shell lip translucent, infills and reduces lip scalloping, spatula becomes whitened.

Reproductive system ( Fig. 66I; n = 2). Positioned within right side of coelom, against foot wall on foot muscle, under the respiratory cavity and digestive glands; epiphallic parts positioned over BM, with singular GP through foot wall; GA very small indistinct; AO relatively large elongated broad centrally bent bluntly pointed (embedded in folds of MG), joined to upper GA; ED elongated broad thickened, centrally bent, joins to lower side of GA; GA, AO, ED all white muscular fibrous tissue; EG large, soft whitish tissue, folded, joins ED and single narrow bent flagellum (F1) as an extension of ED, shorter length. BD and CD connect in opposing directions into GA between ED join and GP, both ducts narrow long straight smooth whitish, pass together through RAM to outerside ( BD over thicker CD) into soft white folded tissues of MG; BC embedded in folds of AG / MG; BD long narrow with prominent distal loop with MA connected to inner anterior foot wall above BM; BC medium bulbous, thin whitish translucent test; MG / AG complex relatively large; HD thickened coiled, links ducts in soft white folded tissues of AG to yellowish granulated HG; AG / MG larger than HG.

Spermatophore ( Fig. 66J ). Test thin, translucent (length = 8.93 mm, n= 1); head evenly cylindrical, bulbous, tip bluntly rounded, containing a white gelatinous core, tapers along the transparent flagellum to a thin tip; both sections smooth, featureless; head much wider and similar length to flagellum (head length = 4.65 mm, 52% of SPM length, head width = 124 μm, flagellum width = 22 μm). 2 SPM tightly coiled embedded in brown gelatinous mass in one BC ( AM C.584788).

Comparative remarks. In our mitochondrial phylogeny, S. caledonica sp. nov. ( laciniosa group, unit 23) is the sister species of S. maloensis (see comparative remarks under this species) ( Figs 1 , 3 ). It differs from other species by COI distances of ≥ 19% (Table S6). We found S. caledonica sp. nov. in sympatry with five congeners on the E coast of NC: For comparisons with S. atra , S. hienghenensis sp. nov., and S. normalis refer to comparative remarks under these species. Siphonaria bourailensis sp. nov. has a shell with slightly more raised ribbing, greater edge scalloping, a paler spatula, and a shorter ED. Siphonaria poindimiensis has a shell with a more central apex, greater edge scalloping, paler spatula, a blunt AO, and a longer ED. The RS resembles that of S. atra and S. viridis . Specimens figured as ‘ laciniosa group, unit 23’ in Dayrat et al. (2014: 262) belong to this species.

Distribution and habitat. Recorded from E and W coasts of NC ( Fig. 70 ). In this study, found on exposed to sheltered rocky boulder and platform shores, mid to upper littoral level ( Fig. 65O ).

Etymology. For New Caledonia, where this species has been found; adjective.

Figures

FIGURE 1. Maximum Likelihood phylogram based on analyses of a concatenated sequence data set of 16S and COI. Branches are collapsed at the species level. Branch labels give unit numbers and accepted species names. Numbers on branches indicate branch support employing 10,000 ultrafast bootstraps.Available genus-group names are shown next to their type species. Scale bar indicating modelled sequence divergence.

FIGURE 3. Maximum Likelihood phylogram (partial, species not collapsed). Clades J–L (laciniosa and plicata groups) of the tree shown in Fig. 1. Branch labels give specimen identifiers for new sequences or Genbank accession numbers for imported sequences from other studies and geographic regions (see Tables S1–S2 for details). Identical haplotypes are merged into single tips. Numbers on branches indicate branch support by employing 10,000 ultrafast bootstraps. Clade names give unit numbers and accepted species names. Scale bar indicating modelled sequence divergence.

FIGURE 65. Shells of S. namukaensis sp. nov., S. ouasseensis sp. nov. and S. caledonica sp. nov. A–F, M–N, P. S. namukaensis sp. nov. A–E, M–N, P. Fiji. A. Holotype AM C.585826 [M282]. B. Paratype AM C.584858 [SK109]. C. Paratype AM C.585824 [M280]. D. Paratype AM C.585825 [M281]. E. Tagaqa, AM C.585822 [M276]. F. NC, Poindimie, AM C.585000 [M461, SK194]. M. Animal. N. In situ. P. Protoconch, Vuda Point, AM C.584864 [M422, SK110]. G–I, Q–R. S. ouasseensis sp. nov., NC, Ouassé. G. Holotype AM C.584786 [M377]. H. Paratype AM C.584800 [SK344]. I. Paratype AM C.585923 [SK346]. Q. Protoconch, AM C.585993 [SK347]. R. In situ. J–L, O, S–T. S. caledonica sp. nov. J. Holotype AM C.584788 [M364], NC, Tiari. K. Paratype AM C.585015 [M366], La Roche Percee. L. Paratype AM C.585838 [M362]. O. In situ, Tiari. S. Animal. T. Protoconch, AM C.585839 [M363]. Unlabelled scale bars = 10 mm.

FIGURE 66. Reproductive morphology of S. namukaensis sp. nov., S. ouasseensis sp. nov. and S. caledonica sp. nov. A–D. S. namukaensis sp. nov. A. Paratype AM C.584858 [SK109], Fiji. B. Holotype AM C.585826 [M282], Fiji. C–D. NC, Poindimie, AM C.584994 [M455, SK193]. E–H. S. ouasseensis sp. nov., NC, Ouassé. E. Paratype AM C.585924 [SK342]. F. Paratype AM C.595984 [SK351]. G–H. AM C.585732 [SK343]. I–J. Holotype of S. caledonica sp. nov. AM C.584788 [M364, SK130]. Scale bars = 1 mm.

FIGURE 70. Known occurrence records of S. ouasseensis sp. nov., S. caledonica sp. nov., S. perexigua sp. nov., S. planucosta sp. nov. and S. bourailensis sp. nov.