Nacella, MACQUARIENSIS FINLAY, 1926

González-Wevar, Claudio A., Hüne, Mathias, Rosenfeld, Sebastián, Nakano, Tomoyuki, Saucède, Thomas, Spencer, Hamish & Poulin, Elie, 2019, Systematic revision of Nacella (Patellogastropoda: Nacellidae) based on a complete phylogeny of the genus, with the description of a new species from the southern tip of South America, Zoological Journal of the Linnean Society 186, pp. 303-336 : 325

NACELLA MACQUARIENSIS FINLAY, 1926

Nacella fuegiensis – Suter, 1913: 77 (not of Reeve).

Nacella delesserti – Hedley 1916: 42, pl. 6, figs 65–69 (not of Philippi).

Nacella macquariensis Finlay, 1926: 337 ; Lindberg, 2008: 272; González-Wevar et al., 2017: 862.

Patinigera macquariensis – Powell, 1955: 68; Dell, 1964: 274.

Nacella (Patinigera) macquariensis – Powell, 1973: 199 (in part), pl. 182, figs 1, 2.

Material studied: For this revision we only had access to tissue samples obtained from ten individuals collected at Garden Cove (54°29’59.15’’ S, 158°56’09.38’’ E), Macquarie Island .

Shell: According to Powell (1973), the shell of this species is moderately large, up to 63 mm in length, strong but of light build. Its shape is narrowly ovate and elevated but varying to rather broadly ovate and depressed. The sculpture consists of 32 to 35 broadly rounded, primary radial ribs, plus narrower secondary intermediate radials, mostly over the posterior half of the shell. The whole surface is crowded with low concentric growth lamellae that do not thicken to any extent on the crest of the radials. The external colour is olive to chestnut-brown; internally, it is diffused and strongly rayed in bronzy reddish brown, the spatula being well-marked, variously blotched with reddish brown, and often almost completely white-callused.

Distribution: Macquarie Island.

Habitat: This species occurs from the high and medium intertidal rocky ecosystem down to 25 m.

Comments: Multi-locus mtDNA and nucDNA reconstructions indicate that Nacella macquariensis from Macquarie Island represents a separate, diagnosable taxonomic unit, closely related to N. edgari (Kerguelen and Heard Islands) and N. terroris (Campbell Island). Accordingly, the distribution of N. macquariensis is restricted to the Macquarie Islands and the species is not present at Kerguelen and Heard (contra Powell, 1973).