Amalda montrouzieri (Souverbie, 1860)

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 : 33-34

Amalda montrouzieri (Souverbie, 1860)

Figs 12 , 13 A–C, 14A–B, 17C–D

Ancillaria montrouzieri Souverbie, 1860a: 207 .

Ancillaria montrouzieri – Souverbie 1860b: 324, pl. 11 fig. 3. — Reeve 1864: pl. 4 fig. 9.

Amalda montrouzieri – Kilburn & Bouchet 1988: 278–281, figs 1–8, 38–39, 51, 53. — Gratecap 2014: 13, 18, figs 1–4.

Type material

Syntypes

NEW CALEDONIA • 1 shell; “Insul. Lifu? (Loyalty). Insul. Art?” [ Souverbie 1860a]; Île des Pins [ Souverbie 1860b]; MNHN IM-2000-1367 • 3 shells; same collection data as for preceding; MNHN IM- 2000-1475 ( Fig. 12 A–C).

Material examined

Sequenced material

SOUTHERN NEW CALEDONIA • 1 lv; Baie du Prony; 12–18 m deep; MNHN IM-2013-80199 .

Not sequenced material

Material mentioned in Kilburn & Bouchet (1988), about 50 lots, 110 specimens.

Description

MEASUREMENTS. Shell medium in size (SL up to 41.5 mm, usually less than 30 mm).

SHELL. Ovate-fusiform, with a cyrtoconoid spire. Primary spire callus thick, weakly microshagreened, covering all whorls, including most of protoconch rendering measurements inaccurate, and with weak spiral lirae (8–10 on penultimate whorl). Secondary callus medium thick, forming extensive pad on right side of spire. Plication plate with 2–4 (usually 3) ridges. Olivoid groove from shallow to rather deep, labral denticle weak, obtuse. Upper anterior band very weakly convex, nearly flat. Lower anterior band flat, smooth. Colour from uniformly white, to chestnut brown. In darker coloured specimens, primary spire callus and upper anterior band darker, olivoid band lighter than body whorl cloak, plication plate white.

RADULA (n =2, not sequenced) ( Fig. 13 A–C). Very similar in these two. Central tooth tricuspid, with central cusp ¼ smaller than lateral ones. All cusps, as well as lateral flaps of central tooth, with irregular distinct serration.

LIVE SPECIMENS ( Fig. 14 A–B). With truncated and notched posteriorly foot. Parapodia opaque, greyish, with scarce slightly darker speckles, can completely envelop shell. Propodium, anterior part of parapodia and siphon with more dense speckles.

Remarks

The species is quite variable in shell shape and particularly in colouration, with many specimens pure white or with lightly coloured secondary callus (e.g., Fig. 12F, I ). The syntypes are the largest examined specimens. Kilburn & Bouchet (1988: 281) mentioned the existence of “a puzzling morph which is uniformly different in shape (although there are indications of intergradation in this regard) and in its faint ancillid (=olivoid) groove” at larger depths (175–420 m) ( Fig. 12 J–K). This morph differs from A. montrouzieri and A.alabaster sp. nov. in its narrower shell with taller spire. It may represent a peculiar morph of A. alabaster sp. nov. or a separate species.

Distribution

Southern New Caledonia. Amalda montrouzieri is normally distributed at depths of 10–70 m, with specimens occasionally collected down to 130 m; a few empty shells were collected at even larger depths, down to 280 m (SMIB 3, stn DW20). Kilburn & Bouchet (1988) cited some extralimital records, mostly on the basis of published records, namely the Loyalty Islands, Fiji, the Ryukyu Islands, and the Philippines. These records should be confirmed with molecular data.

Figures

Fig. 12. Amalda montrouzieri (Souverbie, 1860), southern New Caledonia. A–C. Syntype MNHN IM- 2000-1475, SL 41.4 mm. D–E. MNHN IM-2013-80199, SL 18.7 mm (sequenced specimen). F. Secteur Île Ouen-Baie du Prony, LAGON, stn DW98, 22°35.7′ S, 166°31.8′ E, 15 m, SL 25.6 mm. G. Grand Récif Sud, LAGON, stn DW334, 22°38′ S, 166°53.6′ E, 47–48 m, SL 26.6 mm (illustrated by Kilburn & Bouchet 1988: fig. 14). H. Secteur de Nouméa. LAGON, stn DW51, 22°14.7′ S, 166°11.1′ E, 10 m, SL 27.6 mm. I. Grand Récif Sud, LAGON, stn DW544, 22°50.8′ S, 166°48.5′ E, 25 m, SL 25.4 mm. J–K. A. cf. montrouzieri. Deep-water morph, SMIB2, stn DW23, 22°31′ S, 167°37′ E, 410–420 m, SL 30.2 mm (specimen illustrated by Kilburn & Bouchet 1988: figs 5–6). All specimens except D–E not sequenced. Shells at the same scale.

Fig. 13. Radulae of species of Amalda H. Adams & A. Adams, 1853. A–C. A. montrouzieri (Souverbie, 1860). A–B. Île Ouen – Baie du Prony, LAGON, stn DW239, 22°24.3′ S, 166°57.8′ E, 42–43 m, SL 20.2 mm. C. Grand Récif Sud, LAGON, stn DW544, 22°50.8′ S, 166°48.5′ E, 25 m, SL 25.4 mm (shell on Fig. 12I). D–E. A. alabaster sp. nov. D. Holotype, MNHN IM-2007-43627, SL 26.7 mm (shell on Fig. 15A–B). E. MNHN IM-2007-43636, SL 17.6 mm. F. A. cf. alabaster, MNHN IM-2013-63897, SL 18.1 mm (shell on Fig. 15H–I). G. A. allaryi Bozzetti, 2007, MNHN IM-2013- 68272 (shell on Fig. 17A). H. A. coriolis Kilburn & Bouchet, 1988, MNHN IM-2013-63899 (shell on Fig. 18H–I).

Fig. 14. A–B. Live specimens of Amalda montrouzieri (Souverbie, 1860), Nouméa, 8 m. C–E. Shell and live specimen of A. herberti Cossignani, 2013, Nouméa, South Lagoon, about 250 m. Photos courtesy of David Massemin.