Amalda aureomarginata Kilburn & Bouchet, 1988

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 : 23-27

Amalda aureomarginata Kilburn & Bouchet, 1988

Figs 7H , 8 A–H, 9A

Amalda aureomarginata Kilburn & Bouchet, 1988: 282 , 284, figs 9–12 [not figs 13–17 = Amalda hilgendorfi ].

Amalda aureomarginata – Gratecap 2014 (part): 13, 18, figs 5–8 [not fig. 9 = Amalda hilgendorfi ].

Type material

Holotype

SOUTHERN NEW CALEDONIA • 22°47′ S, 167°15′ E; 430–465 m deep; BIOCAL; stn 45; MNHN IM-2000-1345.

Material examined

Sequenced material

20 sequenced specimens (all MNHN) ( Table 1).

Not sequenced material

SOUTHERN NEW CALEDONIA • 1 dd; S of Île des Pins; 22°55′ S, 167°15′ E; 450 m deep; SMIB 1 ; stn DW09 • 13 dd; SW of Île des Pins; 22°56′ S, 167°15′ E; 437 m deep; SMIB 3 ; stn DW25 • 5 dd; SW of Île des Pins; 22°55′ S, 167°16′ E; 450 m deep; SMIB 3 ; stn DW26 • 6 dd; SW of Île des Pins; 22°46′ S, 167°11′ E; 394 m deep; stn DW28 • 15 dd; SW of Île des Pins; 22°47′ S, 167°12′ E; 405 m deep; SMIB 3 ; stn DW29 • 2 dd; SW of Île des Pins; 22°55′ S, 167°13′ E; 383 m deep; SMIB 3 ; stn DW31 • 6 lv and dd; between Île des Pins and Grand Récif Sud; 22°56′ S, 167°14′ E; 400–420 m deep; SMIB 4 ; stn DW65 • 2 dd; between Île des Pins and Grand Récif Sud; 22°56′ S, 167°15′ E; 400–430 m deep; SMIB 4 ; stn DW66 • 2 dd; between Île des Pins and Grand Récif Sud; 22°55′ S, 167°16′ E; 430–440 m deep; SMIB 4 ; stn DW68 • 1 dd; between Île des Pins and Grand Récif Sud; 22°55′ S, 167°15′ E; 395– 405 m deep; SMIB 4 ; stn DW69 • 2 dd; Antigonia Bank; 23°15′ S, 168°04′ E; 305–335 m deep; SMIB 5 ; stn DW104 • 2 dd; Antigonia Bank; 23°15′ S, 168°04′ E; 311–355 m deep; SMIB 8 ; stn DW185 • 2 dd; 23°17′ S, 168°06′ E; 390–540 m deep; SMIB 8 ; DW187 • ca 30 dd; S of Île des Pins ; 22°48′ S, 167°15′ E; 444–445 m deep; BATHUS 2; stn DW719 • 3 dd; S of Île des Pins ; 22°52′ S, 167°16′ E; 530–541 m deep; SMIB 8; stn DW720 • 4 dd; S of Île des Pins ; 22°50′ S, 167°27′ E; 430–433 m deep; SMIB 8; stn DW723 • ca 15 lv and dd; southwest slope of the Dumbéa Pass ; 22°52′ S, 167°12′ E; 400 m deep; SMIB 8; stn DW729 • 1 dd; Norfolk Ridge ; 23°21′ S, 168°02′ E; 386–390 m deep; BATHUS 3; stn DW829 • 2 dd; south of Grande Terre ; 22°53′ S, 167°12′ E; 390–420 m deep; MUSORSTOM 4; stn DW230 • 4 dd; W of Île des Pins ; 22°47′ S, 167°12′ E; 390–400 m deep; Vauban 1978–1979; stn DR16 • 4 dd; Crypthelia Bank ; 23°20′ S, 168°15′ E; 207–276 m deep; NORFOLK 1; stn DW1728 • 25 dd; SW of Île des Pins ; 22°57′ S, 167°16′ E; 427–433 m deep; NORFOLK 1; stn DW1733 • 20 dd; SW of Île des Pins ; 22°54′ S, 167°13′ E; 403–429 m deep; NORFOLK 1; stn DW1734 • 20 lv and dd; SW of Île des Pins ; 22°53′ S, 167°13′ E; 415–445 m deep; NORFOLK 1; stn DW1735 • 4 dd; SW of Île des Pins ; 22°51′ S, 167°12′ E; 340–381 m deep; NORFOLK 1; stn DW1738 • ca 30 lv and dd; SW of Île des Pins ; 22°51′ S, 167°14′ E; 404–448 m deep; NORFOLK 1; stn DW1739 • 1 dd, Île des Pins ; 22°43′ S, 167°16′ E; 245–300 m deep; NORFOLK 2; stn DW2150 • 30 dd; Île des Pins ; 22°52′ S, 167°13′ E; 453– 455 m deep; NORFOLK 2; stn DW2155 • 1 lv juv; SW of Île des Pins ; 22°48′ S, 167°15′ E; 449–465 m deep; KANACONO; stn DW4697 • 1 lv juv; S of Île des Pins ; 22°59′ S, 167°43′ E; 494–508 m deep; KANACONO; stn DW4746; MNHN-IM-2013-63421 .

Description

MEASUREMENTS. Small to medium-sized (SL up to 34.5 mm).

SHELL. Rather narrow, ovate-fusiform, with narrow base and high, acutely conical spire. First protoconch whorl diameter 0.88–0.94 mm (mean 0.91, n =5). Primary spire callus thick, covering all except protoconch and one or two teleoconch whorls, secondary callus forming fairly thin, linguiform pad, extending to second last suture. Plication plate with 4–7 ridges, sometimes bifid. Olivoid groove rather shallow, labral denticle very weak. Upper anterior band weakly convex, nearly flat, may be slightly thickened at rear edge of anterior band. Lower anterior band flat, smooth. Colour light yellowish-brown with paler olivoid band, spire callus with orange-yellow lower band, bordered abapically by narrow light line and creamy upper band with purple tint. Adapically primary callus with narrow but distinct brown borderline. Parietal callus thick, typically purplish-pink. Upper anterior band yellowish orange, lower anterior band and plication plate white.

RADULA ( Fig. 7H ). With simple rather thin hook-shaped lateral teeth and tricuspid central teeth with central cusp smallest. Outer lower edges of outer cusps serrated.

Remarks

The radula of a specimen illustrated by Kilburn & Bouchet (1988: figs 52–56) is rather similar to ours, but the lateral cusps of the central tooth with serrated inner edges as well.

Kilburn & Bouchet (1988) recognized three local forms: typical (south New Caledonia), Chesterfield (Coral Sea) and northern New Caledonia form, the latter two characterized by a broader oval shell and details of colouration. A molecular analysis, however, revealed that the specimens identified as these two latter forms are in fact subadults of A. hilgendorfi (see Fig. 8I ). They differ from A. aureomarginata by the absence of a characteristic reddish-purple or purplish-pink upper part of the parietal callus and the median part of the primary spire callus. Another stable difference is that in A. aureomarginata , the upper limit of the secondary callus is bordered by a narrow distinct brown band (arrow on Fig. 8H ), which is not present in A. hilgendorfi . The specimen of Amalda cf. aureomarginata from the Chesterfields illustrated by Gratecap (2014) is A. hilgendorfi .

Distribution

The confirmed distribution is confined to southern New Caledonia ( Fig. 9A ), in a limited area off Île des Pins approximately 40 × 30 km, with a few records from adjacent Norfolk Ridge localities. Depth range 305– 541 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. 8. A–H.Amalda aureomarginata Kilburn& Bouchet,1988, southernNew Caledonia.A–C. Holotype, MNHN IM-2000-1345, SL 34.1 mm. D. MNHN IM-2007-43644, SL 26.6 mm. E. MNHN IM-2007- 43655, SL 31.5 mm. F. MNHN IM-2007-43551, SL 30.5 mm. G–H. MNHN IM-2007-43654, SL 28.2 mm. I–J. A. hilgendorfi (von Martens, 1897), MNHN IM-2009-11968, northern New Caledonia, SL 31.6 mm. Shells at the same scale; H, J = enlarged upper part of the shell. Arrow on H points at dark brown line, bordering secondary spire callus.

Fig. 9. Distribution map of Amalda aureomarginata Kilburn & Bouchet, 1988 (A) and A. fuscolingua Kilburn & Bouchet, 1988 (B) off southern New Caledonia. Red circles=the typelocalities; stars= indicate stations where the species were recovered.