Amalda miriky, Kantor & Castelin & Fedosov & Bouchet, 2020

Kantor, Yuri I., Castelin, Magalie, Fedosov, Alexander & Bouchet, Philippe, 2020, The Indo-Pacific Amalda (Neogastropoda, Olivoidea, Ancillariidae) revisited with molecular data, with special emphasis on New Caledonia, European Journal of Taxonomy 706, pp. 1-59 : 27-30

Amalda miriky sp. nov.

urn:lsid:zoobank.org:act:8EF08658-D739-4E15-A521-6BCD0FCBFCA7

Figs 7 I–J, 10

“ form or subspecies” of A. hilgendorfi occurring off Madagascar – Kilburn 1996: 25.

Amalda cf. hilgendorfi – Gratecap 2016b: 4, 12, fig. 5.

Diagnosis

Shell large, up to 53 mm, fusiform, with large dome-shaped protoconch (diameter of first whorl ca 1.25 mm). Primary and secondary calluses very densely and distinctly microshagreened. Olivoid groove very shallow and indistinct. Anterior band separated by distinct fasciolar ridge into upper and twice more narrow lower bands. Upper anterior band has distinct ridge rounded on top. Body whorl cloak from light yellow to light orange, olivoid band pale, upper anterior band orange-brown, lower anterior band and plication plate white. Primary callus orange-brown, spire whorls with slight bluish tint. Protoconch of same colour as primary callus.

Etymology

The species is named after the expedition, itself named after the fishery boat on which the survey was conducted. Used as a noun in apposition.

Type material

Holotype

MADAGASCAR • off NW Madagascar between Nosy-Be and Banc du Leven; 12°38′ S, 48°14′ E; 420–436 m deep; MIRIKY; stn CP3183; MNHN IM-2007-36868 (sequenced).

Material examined

Sequenced material

13 sequenced specimens ( Table 1).

Not sequenced material

OFF NW MADAGASCAR • 5 lv; between Nosy-Be and Banc du Leven ; 12°36′ S, 48°16′ E; 331– 364 m deep; MIRIKY; stn CP3182; MNHN IM-2007-36899, MNHN IM-2007-36879, MNHN IM- 2007-36852, MNHN IM-2007-36869, MNHN IM-2007-36857 • 38 lv, 10 dd; 12°38′ S, 48°14′ E; 420– 436 m deep; MIRIKY; stn CP3183; 1 lv specimen with registration MNHN IM-2007-36881 • 2 lv; 1 dd; 12°40′ S, 48°12′ E; 492–524 m deep; MIRIKY; stn CP3184 • 8 lv; 12°31′ S, 48°22′ E; 298–301 m deep; MIRIKY; stn CP3188; 2 lv specimens with registration MNHN IM-2007-38032 , MNHN IM- 2007-36934 • 22 lv; 11 dd; 12°30′ S, 48°18′ E; 346–376 m deep; MIRIKY; stn CP3189 • 1 dd; 12°43′ S, 48°14′ E; 291–353 m deep; MIRIKY; stn CP3209 • 2 lv, 1 dd; 12°44′ S, 48°12′ E; 442–491 m deep; MIRIKY; stn CP3210 • 4 dd; 12°32′ S, 47°52′ E; 244–300 m deep; MIRIKY; stn DW3211 • 6 lv, 6 dd; 12°34′ S, 47°54′ E; 367–369 m deep; MIRIKY; stn DW3212; 2 lv with registration MNHN IM- 2007-38051 ; MNHN IM-2007-36682 • 5 lv, 6 dd; 12°31′ S, 47°52′ E; 262–289 m deep; MIRIKY; stn DW3213 • 4 lv, 2 dd; 12°33′ S, 47°52′ E; 302–327 m deep; MIRIKY; stn DW3214 • 14 lv, 9 dd; 12°32′ S, 47°54′ E; 316–433 m deep; MIRIKY; stn DW3215 • 4 lv, 2 dd; 12°34′ S, 47°52′ E; 296–350 m deep; MIRIKY; stn DW3216; 3 lv; MNHN IM-2007-38073 ; MNHN IM-2007-38074 ; MNHN IM- 2007-36669 • 2 lv, 1 dd; 12°33′ S, 47°56′ E; 391–438 m deep; MIRIKY; stn DW3217 • 1 lv; 12°46′ S, 48°12′ E; 355–380 m deep; MIRIKY; stn CP3224 • 4 lv; 12°55′ S, 48°11′ E; 260–319 m deep; MIRIKY; stn DW3228 • 1 dd; West of Cap d’Ambre ; 12°08′ S, 48°53′ E; 496–501 m deep; MIRIKY; stn DW3195 • 6 dd; 12°07′ S, 48°58′ E; 362–431 m deep; MIRIKY; stn DW3197 • 1 dd; 12°06′ S, 48°57′ E; 527– 652 m deep; MIRIKY; stn DW3199.

Description (holotype)

MEASUREMENTS. SL 39.6 mm, AL 19.2 mm, SW 14.9 mm.

SHELL. Shell fusiform with relatively broad base, SW/SL 0.37; body whorl evenly convex on right side, very slightly drawn in at olivoid groove, evenly convex on left side, greatest width of body whorl median. Protoconch ( Fig. 10 D–E) large, broadly domed, first 0.75 whorls with distinct impressed suture, further suture overlaid by callus. Protoconch borders indistinct, rendering whorl count impossible. Diameter of first whorl 1.23 mm. Spire high, conical; primary callus not thick and covering all whorls except protoconch, slightly impressed at sutures; surface of callus weakly glossy, very densely and distinctly microshagreened; secondary callus very thin, extending to right-ventral side of last whorl and continuing up as fairly thin, tongue-shaped pad, reaching suture of antepenultimate whorl. Surface of secondary callus very similar to that of primary one, borders indistinct. Body whorl cloak glossy, covered by microscopic, dense, waving striae. Olivoid groove very shallow and indistinct, its presence detected by different colours of body whorl cloak and olivoid band rather than by actual depression of surface. Rear edge of anterior band very sharp and distinct. Anterior band strongly microshagreened, mat, and separated into upper (broader) and lower bands by distinct fasciolar ridge. Broader upper anterior band with distinct ridge rounded on top. Lower anterior band nearly flat, nearly twice narrower than upper band. Plication plate with deep and broad groove in upper third, separating adapical largest spiral ridge, followed by another deep groove and four spiral ridges progressively weakening abapically. Columella with indistinct spiral ridges visible as far as rear edge of anterior band. Aperture narrow oval, acute posteriorly, widest medially; outer lip rather thin, in side view very slightly opisthocline, nearly concave, with slight, blunt labral denticle not exactly corresponding to olivoid groove; siphonal notch shallow, symmetrically U-shaped. Body whorl cloak light orange, olivoid band light yellow, upper anterior band orange-brown, lower anterior band and plication plate white. Primary callus orange-brown, similar in tint, but slightly darker than anterior band, abapically to primary callus very narrow whitish spiral band, spire whorls with slight bluish tint. Protoconch of same colour as primary callus. Outer lip inside and lower part of aperture white, aperture inside light pinkish.

RADULA (n= 2, not sequenced). Lateral teeth simple, thin, hook-shaped. Central teeth tricuspid, with central cusp much thinner and smaller than lateral ones ( Fig. 7J ). Lateral cusps with serrated sides. In one specimen central cusp subdivided into two very small cusplets ( Fig. 7I ), lateral cusps with smooth edge.

Remarks

The species, which may reach 53.4 mm, is variable in shell slenderness and colouration. The holotype is an average dark specimen, while some specimens are much lighter; some specimens may also have a distinct purplish tint on the secondary callus.

Molecular analysis clearly demonstrates that this is a separate species, although there is a morphological similarity with A. hilgendorfi . Both species are reliably distinguished by the protoconch: in A. miriky sp. nov. it is much larger (first protoconch whorl diameter of more than 1.2 mm vs 0.75–0.92 mm in A. hilgendorfi ). Another somewhat similar species from the western Indian Ocean is A. trippneri Kilburn, 1996 from Saya de Malha Bank, depth unknown. The latter differs from A. miriky sp. nov. in its more narrow shell with much taller spire, the presence of the spiral lirae on the spire, as well as indistinct, rather deep, olivoid groove. In general outline and colour, Amalda miriky sp. nov. is also similar to A. hayashii Ninomiya, 1988 , differing in exposed protoconch, not covered by callus, by a narrower olivoid band, by completely white plication plate and by more slender shell.

Distribution

North-western Madagascar, alive in 289– 760 m.

Figures

Fig. 7. Radulae of species of Amalda H. Adams & A. Adams, 1853. A–G. A. hilgendorfi (von Martens, 1897). A–B. MNHN IM-2019-621 (shell on Fig. 4D). C. MNHN IM-2009-11961 (shell on Fig. 4J). D. MNHN IM-2013-58045, Papua New Guinea. E. MNHN IM-2013-19909, Papua New Guinea. F. MNHN IM-2013-63430, southern New Caledonia. G. MNHN IM-2007-33312 (shell on Fig. 5F). H. A. aureomarginata Kilburn & Bouchet, 1988, MNHN IM-2013-63421, specimen not sequenced, southern New Caledonia. I–J. A. miriky sp. nov. I. Miriky, stn CP3210, specimen not sequenced, Madagascar. J. Miriky, stn DW3215 (shell on Fig. 10J). K–L. A. cacao sp. nov., holotype, MNHN IM- 2000-35296 (shell on Fig. 11A–E).

Fig. 10. Amalda miriky sp. nov., Madagascar. A–E. Holotype, MNHN IM-2007-36868, SL 39.6 mm (D–E=enlarged lateral and apical views of the protoconch). F. MNHN IM-2007-38073, SL 35.8 mm (specimen not sequenced). G. MNHN IM-2007-36842, SL 35.7 mm. H. MNHN IM-2007-36866, SL 37.9 mm. I. MNHN IM-2007-38064, SL 30 mm. J. Miriky, stn DW3215, between Nosy-Be and Banc du Leven, 12°32′ S, 47°54′ E, 316–433 m, SL 38.9 mm (specimen not sequenced, radula on Fig. 7J). Scale bars: A–C, F–J= 2 cm; D–E = 1 mm.