Siphonaria asghar Biggs, 1958

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 : 133-135

Siphonaria asghar Biggs, 1958

( Figs 49H–N, Q–S , 50G–H )

Siphonaria asghar Biggs 1958: 249 (type locality: Hormuz Island, Persian Gulf).— Biggs 1973: 375; Galindo 1977: 416; Christiaens 1980: 81; Vakani et al. 2021: 134, fig. 2b.

Siphonaria tenuicostulata —Smythe 1982: 80, pl. 4g (not S. tenuicostulata Smith, 1903)

Siphonaria ashgar — Bosch et al. 1995: 184, fig. 858; Ali et al. 2011: 1086, fig. 1B; White & Dayrat 2012: 61, 70; Dayrat et al. 2014: 266, ‘unit 3’, fig. 3C; Gonzàlez-Wevar et al. 2018: 5, fig. 2 (incorrect subsequent spellings of asghar ).

Material examined. Type material. Holotype of S. asghar Biggs, 1958 from Hormuz Island, Persian Gulf; coll. 12 May 1933 ( NHMUK 1958.6.13.13 , Fig. 49H ). Six paratypes of S. asghar Biggs, 1958 same data as holotype ( NHMUK 1958.6.13.14–19 , Figs 49I–K ).

Other, non-type material. Pakistan: Karachi , Clifton Beach , 24°45.500’N, 67°05.968’E,PA02-1( AMC.585895 p); French Beach , 24°50.345’N, 66°49.244’E, PA01-2 ( AM C.585899 5p); 24°50.367’N, 66°49.387’E, PA01- 1 ( AM C.585818 13p, C.585843 p [M243], C.585844 p [M244], C.585845 p [M245], C.585846 p [M456, SK190]); Karapir Beach, 24°50.590’N, 66°53.927’E, PA01-3 ( AM C.585901 7p, C.585847 p [SK144], C.585854 p [M235], C.585855 p [M236], C.586001 p [SK532]); Bubiji Beach, 24°53’N, 67°01’E 24°53’N, 67°01’E ( WAM S72336 9p, S74084 p [SK408], S74085 p [SK407], S74086 p [SK303], S74087 p [SK359], S74088 p [SK421]), S113648 [SK530], S113649 [SK531] ).

Taxonomic remarks. The holotype of S. asghar ( Fig. 49H ) is a worn or malformed specimen, unlike the paratypes ( Fig. 49I–K ). Our delineation of this species is based on comparative analyses of the morpho-anatomy and mitochondrial genetics of freshly collected topotypes ( Fig. 49L, M ; Table S1). Smythe (1979: 69) incorrectly considered S. asghar as a synonym of S. rosea (= S. crenata ). However, both species differ conchologically and anatomically. The RS structure of S. tenuicostulata (= S. carbo ) figured in Hubendick 1947a: fig. 1) differs from that of S. asghar . A specimen figured as ‘ S. asghar ’ in Dayrat et al. 2014: fig. 3C) corresponds well with the paratypes; Figs 49I–K ). Compared to freshly preserved specimens from Karachi ( Figs 49L–M ), the types ( Figs 49H–K ) are rather small, around half the size of the topotypes.

External morphology. Foot sole, foot wall, foot edge cephalic folds and pneumostomal lobe evenly cream coloured; black pigmentation absent except for central patch on cephalic folds; mantle cream coloured, narrower than foot wall, edge lobed thickened; pneumostome under mantle between right ADMs.

Shell ( Figs 49H–N, Q, R ; Table S9). Small sized (max sl mean = 15.1 mm, SD = 2.2 mm, n = 8), ovate, height medium; apex offset weakly to posterior and left, apex usually eroded (often upper 2/3rds eroded), apical sides strongly convex, protoconch direction undetermined, shell whorl dextral; growth striae inconspicuous, shell thickness medium; rib count (mean = 45, SD = 4.9, n = 8), ribs flat/unraised, narrow, sometimes wavy, very even in width, pale grey/brown; non-protruding at shell lip; shell edge weakly corrugated, not scalloped; few secondary ribs, rib interstices darker; siphonal ridge indistinct. Interior shell margin brown and white; brown rays even in width and depth, widen from lip to margin, align under rib interstices, siphonal groove indistinct; spatula and ADM scar chocolate brown paler in parts; ADM scar distinct, CMS weakly convex.

Smaller shells tend to display greater white rays on shell margin, a paler brown / white spatula. Juvenile specimens show paired primary ribs over siphonal ridge.

Reproductive system ( Fig. 50G; n = 4). Positioned within coelom under the respiratory cavity, hermaphroditic glands positioned to posterior against right foot wall and on foot muscle, epiphallic parts positioned between RAM and BM, EG in front of BM, F1 lies on foot muscle to left side/under BM; AO small, broad, rounded, MA on side, bluntly pointed, joins at top of larger GA; ED relatively short (often embedded in soft tissue), narrow, straight; EG medium with folds, broad flagellum F1 appears as an extension of ED at join with EG; AO, GA and ED all muscular white tissue; BD and CD closely connecting, join into GA close to ED and AO (very distinct); BD longer and narrower than CD without distal loop or MA, CD and BD smooth, narrow, both pass together through RAM ( BD above CD) and bent before connecting into folds of MG; BC embedded in MG, size medium, bulbous test soft translucent; HD long, brown flecked, sac-like, edge lobed, links AG to small elongated narrow brownish granulated HG; MG and AG small folded soft white tissue; SV embedded within AG, AG larger than HG, sides match curvature of inner foot wall at right posterior quarter of coelom.

Spermatophore ( Fig. 50H ). Elongated drop-shaped, test thin, translucent (length = 1.28 ± 0.3 mm, n = 3), head bulbous, broad, tip bluntly rounded, containing a white gelatinous mass; taper region to flagellum reduced; both sections; head much larger than flagellum (head length = 0.85 ± 0.03 mm, n = 3, ~ 66% of SPM length); tip bluntly rounded; head section much thicker than flagellum (head width = 580 ± 51 μm, flagellum width = 120 ± 35 μm, n = 3), both sections smooth, featureless; 3 SPM tightly coiled in one BC ( AM C.586001).

Comparative remarks. Siphonaria asghar ( pectinata group, unit 3) is the sister species of the species pair S. carbo and S. itampoloensis sp. nov. ( Figs 1 , 4 ). It differs from these species by COI distances of ≥ 10.9% ( S. itampoloensis ) and ≥ 11.1% ( S. carbo ) (Table S8). Siphonaria asghar has been found in sympatry with four congeners at Karachi, Pakistan: For comparisons with S. crenata , S. belcheri , and S. kurracheensis refer to comparative remarks under these species. Siphonaria perexigua sp. nov. has a taller, internally paler shell with less raised and wider ribs, shorter, bulbous AO, longer and narrower BD, wider ED and a longer F1. Conchologically similar are S. capensis ( SE Africa) and S. striata sp. nov. ( Madagascar), but S. asghar exhibits finer, more numerous, and flatter ribs.

Distribution and habitat. Coasts of the Arabian Sea, recorded at Q’rum, Muscat ( Oman), Karapir, Karachi ( Pakistan) and western coast of India ( Fig. 51 ). In this study found in sheltered positions on exposed rocky shores, upper and mid littoral levels ( Fig. 49S ).

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 4. Maximum Likelihood phylogram (partial, species not collapsed). Clades C–F (normalis, lateralis and pectinata 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 49. Shells of S. monticulus, S. alba and S. asghar. A–C, O–P, T. S. monticulus. A. Lectotype of Hebesiphon monticulus AM C.103720. B–C. NC, Lifou, TS. B. AM C.584951 [M387]. C. AM C.584950 [M386]. O. Protoconch, AM C.584945 [SK056]. P, T. Lifou, in situ and animal. D–G, U–V. S. alba. D. Singapore, ZRC.MOL.24915 [SK294]. E. Singapore, AM C.585230 [M334] F. WA, AM C.585299 [M070]. G. Singapore, AM C.585237 [SK175]. U–V. Singapore, in situ and animal. H–N, Q–S. S. asghar. H. Holotype NHMUK 1958.6.13.13. I–K. Paratypes NHMUK 1958.6.13.14. L–R. Pakistan, Karachi, TS. L. AM C.585845 [M245]. M. AM C.585844 [M244]. N. AM C.585846 [M256, SK190]. Q. AM C.586001 [SK532]. R. AM C.585855 [M236]. S. In situ. Unlabelled scale bars = 10 mm.

FIGURE 50. Reproductive morphology of S. monticulus, S. alba, S. asghar and S. propria. A–D. S. monticulus, TS, Lifou. A–B. AM C.584951 [M387]. C–D. AM C.584944 [SK057]. E–F. S. alba, Singapore, Lazarus Is, AM C.585237 [SK175]. G–H. S. asghar. G. Pakistan, Karachi, AM C.585846 [M458, SK190]. H. Karachi, AM C.586001 [SK532]. I–K. S. propria NZ, N Island, NMNZ M.331452 [M509]. Scale bars = 1 mm.

FIGURE 51. Known occurrence records of S. alba, S. asghar, S. propria, S. jeanae, S. emergens, S. oblia and S. campestra sp. nov.