Ethalia lampra ( Watson, 1880 )

Herbert, David G., 2024, The Umboniinae (Mollusca: Gastropoda: Trochidae) of New Caledonia, with descriptions of two new genera and eight new species, plus an additional new species from the Bismarck Sea, European Journal of Taxonomy 973, pp. 1-143 : 12-15

Ethalia lampra ( Watson, 1880)

Figs 5–7

Trochus (Solariella) lamprus Watson, 1880: 93 . Type locality: Levuka, Fiji, 12 fath. [22 m], 29/vii/1874.

Trochus (Solariella) lamprus – Watson 1886: 74, pl. 6 fig. 9.

Monilea (Minolia) lampra – Pilsbry 1889 –1890: 272, pl. 36 figs 17–18.

Ethalia lamprus [sic] – Herbert 1992: 409, figs 123–124 (holotype).

Material examined

Holotype ( Fig. 5A–D )

FIJI • empty shell; Ovalau Island , off Levuka; 17°41′ S, 187°50′ E; depth 12 fathoms [22 m]; 29 Jul. 1874; HMS Challenger leg.; NHMUK 1887.2 .9.291 .

Other material

NEW CALEDONIA – Grande Terre, Koumac • 1 specimen, dead; Chenal de l’Infernet, Stn 1304; 20°38.6′ S, 164°13.2′ E; depth 12–15 m; Oct. 1993; Expédition Montrouzier leg.; sable gris, dalle; MNHN • 1 specimen, dead; Stn KD568; 20°40.1′ S, 164°14.3′ E; depth 2 m; 16 Nov. 2019; KOUMAC 2.3 leg.; sable blanc et quelques débris coralliens; MNHN • 1 specimen, living; Stn KD559; 20°46′ S, 164°15.5′ E; depth 12–14 m; 14 Nov. 2019; KOUMAC 2.3 leg.; sable blanc; MNHN • 1 specimen, dead; Stn KD553; 20°47.9′ S, 164°17.2′ E; depth 5–10 m; 13 Nov. 2019; KOUMAC 2.3 leg.; sable blanc; MNHN . – Grande Terre, Nouméa • 1 specimen, dead; Grand Récif Aboré, Stn 1346; 22°21.9′ S, 166°16.1′ E; depth 5–6 m; 5 Oct. 1992; P. Bouchet leg.; fonds blanc; MNHN . – Loyalty Islands, Lifou • 5specimens, dead; Baie du Santal, north of CapAimé Martin [=Acadro], Stn 1448; 20°45.8′ S, 167°01.6′E; depth 20 m; 17 Nov. 2000; Atelier LIFOU 2000 leg.; aspirateur, fonds durs; MNHN • 1 specimen, dead; Baie du Santal, NE of Baie de Gaatcha, Stn 1444; 20°55′ S, 167°05.2′ E; depth 9–20 m; 26 Nov. 2000; Atelier LIFOU 2000 leg.; pente alternant zones caillouteuses “mortes” et passées sableuses grossières; MNHN • 1 specimen, dead; Baie du Santal, W of Pointe d’Easo, Stn 1451; 20°47.3′ S, 167°06.8′ E; depth 10–21 m; 19 Nov. 2000; Atelier LIFOU 2000 leg.; 2 ème patate corallienne; MNHN • 5 specimens, living; Baie du Santal, W/SW of Pointe d’Easo, Stn 1430; 20°47.5′ S, 167°07.1′ E; depth 20–25 m; 9 Nov. 2000; Atelier LIFOU 2000 leg.; patates coralliennes, passées séd.; MNHN • 1 specimen, living; Baie du Santal, between Îlot Huca Hutighé and coast, Stn 1421; 20°52.4′ S, 167°08.5′ E; depth 4 m; 26 Nov. 2000; Atelier LIFOU 2000 leg.; sable grossier sur dalle; MNHN • 1 specimen, dead; Baie du Santal, in front of Chépénéhé, Stn 1415; 20°47.1′ S, 167°09.1′ E; depth 3–7 m; 25 Nov. 2000; Atelier LIFOU 2000 leg.; sable; MNHN .

Description ( Fig. 5 )

SHELL. A relatively small, lenticular to globose-lenticular species (diameter up to 8.0 mm), H/D somewhat variable (0.6–0.73); shell glossy, sculpture weak; periphery below mid-whorl, weakly angled; suture shallowly channelled; base somewhat flattened, umbilicus relatively narrow. Second teleoconch whorl with ± 6 spiral lirae, abapical one strongest, forming a weak, shallowly undulant, suprasutural cord ( Fig. 6A–B ) that evanesces during third whorl; juveniles of 2–3 whorls with a weakly angled periphery delineated by a similar cord; subsequent sculpture appearing to comprise incised striae rather than raised lirae, their spacing and strength variable; microscopic thread-like axial sculpture present with weak, but regular collabral growth-lines developing on last whorl; much of base almost completely smooth save for axial microsculpture, but thickened peri-umbilical area bearing microscopic spiral lirae and curved axial threads. Umbilicus open, relatively narrow with thickened rim and broad internal funicle; columella lip thick, appearing bilobed due to an ear-like reflection at end of umbilical funicle and a flattened pad at end of thickened umbilical rim, both with fine, pustular microsculpture, the latter also with indistinct transverse ridges.

COLOUR. Pattern variable; apical whorls whitish with sparse flecks, later whorls more heavily mottled with blotches and zig-zag lines of white and shades of olive-green/brown and brownish-grey; also with spiral capillary lines of alternating white and darker chevron-like marks; periphery with a white spiral band broken by darker markings; base with similar but more faint patterning. Coloration of some specimens largely shades of pink rather than green/brown/grey. There is commonly a small dark maroon spot on the upper portion of the reflected callus at the end of the umbilical funicle.

DIMENSIONS. Protoconch ( Fig. 6C ). As in Ethalia montrouzieri , diameter ± 185 µm.

OPERCULUM ( Fig. 6D ). As in Ethalia montrouzieri .

RADULA. Not examined.

EXTERNAL ANATOMY. As in E. montrouzieri .

Habitat

Sandy substrata. On Grande Terre, all localities are in the outer portion of the lagoon, on the inner edge of the barrier reef; at depths of 4–20 m (living specimens the same).

Distribution ( Fig. 7 )

Known only from New Caledonia (Grande Terre and Lifou) and Fiji. A similar distribution to that of Ethminolia hickmanae sp. nov.

Remarks

This species has not been recorded since it was first discovered nearly 150 years ago, on 29 th July, 1874. Mentions of it in the literature have been few, offering only revised opinions regarding its generic position (see chresonymy above). Comparison of the Fijian holotype (NHMUK 1887.2.9.291, Fig. 5A– D ) with material from New Caledonia leaves little doubt that the latter is conspecific. The holotype is somewhat smaller than the largest New Caledonian specimens, but as Watson (1880) noted “it is not quite full-grown”. Its coloration is also more brownish, but this may well be due to its age and the fact that it was not collected alive. The Fijian type locality is only ± 1250 km distant from New Caledonia and most probably the species will also be found to occur in the intervening area, around the islands of Vanuatu. Ethalia lampra differs from other New Caledonian Ethalia species in being smaller (diameter <10.0 mm) and in having a patent umbilicus with a thickened rim and internal funicle.

Figures

Fig. 5. Ethalia lampra (Watson, 1880). A–D. Holotype of Trochus (Solariella) lamprus Watson, 1880, diameter 6.1 mm (NHMUK 1887.2.9.291), images courtesy of Kevin Webb, NHM Photo Unit. © The Trustees of the Natural History Museum, London. E–H. Koumac, Stn KD559, height 5.6 mm, diameter 7.7 mm (MNHN). I–K. Lifou, Stn 1421, diameter 7.5 mm (MNHN).

Fig. 6. Ethalia lampra (Watson, 1880) (all MNHN). A. Oblique view of apical whorls showing thickened peripheral and suprasutural cords. B. Apical view of early whorls showing shallowly undulant suture on second teleoconch whorl. C. Protoconch.D. Operculum.A–C. Lifou, Stn 1430. D. Koumac, Stn KD559. Scale bars: A =0.5 mm; B= 200 µm; C= 50 µm; D =1.0 mm.

Fig. 7. Distribution of Ethalia lampra (Watson, 1880). Type locality indicated in pink.