Siphonaria pravitas, 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 : 175-176

Siphonaria pravitas sp. nov.

( Figs 69G–H , 71A–B, M–N, S )

Material examined. Type material. Holotype,from Laings Point , 33°50.419’S, 151°16.638’E, Sydney Harbour, NSW, Australia; coll. B.W. Jenkins, NSW06-3, 19 April 2018 ( AM C.585040 [M192], Fig. 71A [SK118 (RS and SPM)], Fig. 69G ) . Paratypes same data as holotype ( AM C.585334 p; C.585038 p [M153], Fig. 71B ; C.585039 p [M166]) .

Other, non-type material. Australia, LHI: Signal Point , 31°31.501’S, 159°03.580’E, LHI 2017Apr04 -099 ( AM C.608190 p [M010]), LHI 2017Apr04 -104 ( AM C.585939 p) . NSW: Sydney , Spit Bridge , 33°48.198’S, 151°14.860’E ( AM C.546769 4p, C.546766 p [SK432 protoconchI4]); LaingsPoint , 33°50.419’S, 151°16.638’E, NSW06-3 ( AM C.585033 p [M191]); Spit Bridge 2, 33°48.270’S, 151°14. 520’E ( AM C.546764 p; C.546767 2p; C.608191 p, C.595942 p [SK186 protoconch I3]); 100 m NW of Spit Bridge, 33°48.210’S, 151°14.664’E ( AM C.608194 p) .

External morphology ( Fig. 71N ). Foot sole, foot wall and mantle smooth, evenly cream to yellow, paler at foot edge; regular vertical uneven bands/stripes on foot wall, roughly align with rib interstices, fades to none at join of foot wall and mantle; narrow cream pneumostomal lobe under mantle; black pigmentation heavy dark over front of cephalic folds; foot wall shows black blotches; fringing mantle translucent, narrow, covers shell mantle, outer edge thickened, lobed, none to slight black pigmentation aligning with rib interstices; pneumostomal lobe within mantle between the right ADMs, closes the pneumostomal and anal openings at the mantle edge; two small black epithelial eye spots centralised on two thick brownish yellow centrally touching cephalic folds; genital pore inconspicuous, located on foot wall to right anterior of right cephalic fold.

Shell ( Figs 71A, B, S ; Table S3). Size medium (max sl mean = 18.03, SD = 0.87, n = 5), elongate ovate; low; apex offset central sightly to left, apical sides straight, posterior concave; protoconch direction homostrophic (n = 3; Fig. 71S ), shell whorl dextral, growth striae uneven, distinct, protoconch area dark brown; shell thick; rib count (mean = 38.8, SD = 3.3, n = 5), 12–16 primary ribs pale white, bent, crooked to shell lip, rib ridges rounded, increasingly raised and broaden to shell edge, weakly protrude beyond shell lip to unevenly scallop and corrugate the edge; 3- 4 interspersed pale white less raised secondary ribs, rib interstices brown; paired primary ribs on siphonal ridge. Interior shell margin dark to golden brown, white/cream rays under primary and secondary ribs, extend to dark chocolate brown blotched white spatula; siphonal groove distinct, whitish; ADM scar distinct, chocolate brown to whitish, CMS straight; no thickening of shell lip noted; pale variety may occur.

Reproductive system ( Fig. 69G; n = 2). Positioned within coelom under the respiratory cavity, hermaphroditic glands positioned to posterior against right foot wall and over foot sole, epiphallic parts positioned to anterior between BM and RAM. Join of AO and GA indistinct, AO elongated, bluntly pointed, centrally bent with MA, much larger than GA, much thicker than ED; ED relatively long, slightly twisted, narrow; EG white, folded, elongated; single flagellum F1 on EG, long, looped, narrow; AO, GA and ED all muscular white tissue; BD and CD with opposing connections to GA between ED, AO and GP; BD slightly longer and thinner than CD with a prominent loop on anterior side, both ducts smooth and pass together through RAM connecting into MG ( BD above CD), BC translucent, white test, mid-sized and bulbous; HD short, coiled, links AG to a small elongated narrow brownish finely granulated HG, inner edge firmly moulded; MG and AG small, folded, soft white tissue; purple SV embedded on left side of AG, AG larger than HG, sides match curvature of inner foot wall at right posterior quarter of coelom.

Spermatophore ( Fig. 69H ). Long cylindrical, body long; test thin, short tapering section merging head with filamentous flagellum; head bluntly rounded, central whitE, WAvy core, longer thicker than translucent flagellum (head length = 7.09 mm, head width = 160 μm n = 1; flagellum incomplete); 2 tightly coiled SPMs in bursa of one specimen ( AM C.585040).

Comparative remarks. In our mitochondrial phylogeny ( Figs 1 , 2 ), S. pravitas sp. nov. ( atra group, unit 51) is the sister species of S. scabra (unit 50). Both species differ by COI distances of ≥ 8.2%. From any other species S. pravitas differs by COI distances of ≥ 23.5% (Table S4). Siphonaria scabra differs by having a higher shell with less raised ribs and less developed edge scalloping, a larger AO, longer ED, smaller BC, a longer, narrower BD with distal loop, a longer SPM. We found S. pravitas sp. nov. in sympatry with eight congeners throughout its range. Six congeners are sympatric in Sydney Harbour, NSW: For comparisons with S. stowae , S. denticulata , S. diemenensis , S. funiculata , S. scabra , and S. zelandica refer to comparative remarks under these species. Two congeners are sympatric in LHI: Refer to comparative remarks under S. lentula and S. exulum .

Distribution and habitat. Recorded as endemic to SE Australia ( Fig. 73 ). In this study, found on sheltered rocky shores, at upper to mid littoral levels ( Fig. 71M ).

Etymology. From ‘pravitas’ (Latin = ‘crookedness, inequality, irregularity or deformity’) referring to the crooked waviness of the radial ribs on the shell of this species; noun in apposition.

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 2. Maximum Likelihood phylogram (partial, species not collapsed). Clades G–I (atra group) 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 (seeTables 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 spread over two pages.

FIGURE 69. Reproductive morphology of S. perexigua sp. nov., S. planucosta sp. nov., S. bourailensis sp. nov. and S. pravitas sp. nov. A–B. Paratype of S. perexigua sp. nov. AM C.585183 [SK187]. C–D. Holotype of S. planucosta sp. nov. AM C.584826 [M446, SK229]. E–F. Holotype of S. bourailensis sp. nov. AM C.585017 [M368]. G–H. Holotype of S. pravitas sp. nov. AM C. 585040 [M192, SK118]. Scale bars = 1 mm.

FIGURE 71. Shells of S. pravitas sp. nov., S. recurva sp. nov., S. restis sp. nov., S. rodriguensis sp. nov. and S. striata sp. nov. A–B, M–N, S. S. pravitas sp. nov. A. Holotype AM C.585040 [M192, SK118]. B. Paratype AM C.585038 [M153]. M. Sydney Harbour, in situ. N. Sydney Harbour, animal, S. Protoconch, AM C.546766 [SK432]. C. Holotype of S. recurva NMHN IM-2013- 55336 [M534]. D–H, O–P. S. restis sp. nov., WA, Kalbarri. D. Holotype WAM S74049 [M400]. E. Paratype WAM S74048 [M100]. F. Paratype AM C.585200 [M313]. G. Paratype AM C.585919 [SK150]. H. Rottnest Is, AM C.584943 [SK154]. O. Animal. P. Protoconch, AM C.585009 [SK063]. I, Q–R. S. rodriguensis sp. nov. I. Holotype AM C.585197 [SK330]. Q. Protoconch, AM C.585196 [M427]. R. In situ. J–L, T. S. striata sp. nov., Madagascar, Itampolo. J. Holotype AM C.584952 [M264]. K. Paratype AM C.584953. L. Paratype AM C.584954. T. Protoconch, paratype AM C.584953 [M265]. Scale bars = 10 mm.

FIGURE 73. Known occurrence records of S. pravitas sp. nov., S. recurva sp. nov., S. restis sp. nov., S. rodriguensis sp. nov., S. striata sp. nov., S. tagaqaensis sp. nov., S. tanchaensis sp. nov. and S. tanguissonensis sp. nov.