Nacella DEAURATA

NACELLA DEAURATA (GMELIN, 1791)

(FIG. 5)

Patella aenea Martyn, 1784: pl. 1, fig. 17 (invalid).

Patella deaurata Gmelin, 1791: 3719; Strebel, 1907: 137, pl. 5, figs 62, 65, 68, 70; pl. 6, figs 76, 81; Carcelles, 1950: 52, pl. 1, fig. 13.

Patella varicosa Reeve, 1854: pl. 11, fig. 21A–C.

Patella fuegiensis – Reeve, 1855; pl. 28, fig. 73A, B; Rochebrune & Mabille, 1885: 95.

Nacella strigatella Rochebrune & Mabille, 1885: 110.

Nacella (Patinella) aenea – Pilsbry, 1891: 118, pl. 46, figs 28, 36.

Patinella delicatissima – Strebel, 1907: 145; pl. 5, figs 71, 72, 74, 75; Strebel 1908: pl. 1, figs 75, 75A.

Helcioniscus benneti – Preston, 1913: 221, pl. 4, fig. 7.

Patella delicatissima – Melvill & Standen, 1914: 114; Carcelles, 1950: 52, pl. 1, fig. 14.

Nacella (Patinigera) aenea – Wenz, 1938: 328, fig. 401. Patinigera aenea – Powell, 1951: 82.

Patinigera fuegiensis – Powell, 1955: 67.

Patinigera delicatissima – Powell, 1951: 82; Dell, 1964: 273; Castellanos & Landoni, 1988: 24, pl. IV, fig. 4; Aguirre, 2003: 20.

Patinigera deaurata – Dell, 1964: 273; Aguirre et al., 2006: 251.

Nacella (Patinigera) fuegiensis – Powell, 1973: pl. 177, figs 1, 2; Ramírez, 1981: 53.

Nacella (Patinigera) deaurata deaurata – Powell, 1973: 195; Ramírez, 1981: 56; Linse, 1999: 400.

Nacella (Patinigera) deaurata form delicatissima – Powell, 1973: 195; pl. 178, figs 3, 4; Ramirez, 1981: 57; Linse, 1999: 400.

Nacella (Patinigera) delicatissima – Cantera & Arnaud, 1985: 34; Valdovinos & Rüth, 2005: 506; de Aranzamendi et al., 2009.

Nacella (Patinigera) deaurata – Morriconi & Calvo, 1993: 135; Mutschke et al., 1998: 8; Morriconi, 1999; 417; Malanga et al., 2005: 551; Valdovinos & Rüth, 2005: 505, fig. 5A; de Aranzamendi et al., 2009: 1; Aguirre et al., 2009: 252; Thatje & Rios, 2010: 97.

Nacella deaurata – Rios & Gerdes, 1997: 50; Adami & Gordillo, 1999: 186; Ríos & Mutschke, 1999: 196; Aguirre et al., 2009: 419; González-Wevar et al., 2010: 116; 2011a: 1937; 2017: 864; Aldea & Rosenfeld, 2011; 117; Ojeda et al., 2014: 504; Rosenfeld et al., 2013: 11; 2015 b; 55; 2016: 77; 2017: 4; 2018: 1.

Nacella (Patinigera) fugiensis [sic.] – Linse, 1999: 400. Nacella (Patinigera) magellanica – Valdovinos & Rüth, 2005: 509 (in part, not of Helbling).

Nacella delicatissima – Aguirre et al., 2006: 252; Aguirre et al., 2009: 454; González-Wevar et al., 2011a: 1937.

Nacella fuegiensis – González-Wevar et al., 2011a: 1937.

Material studied: London Island, Pacific Patagonia (54°40’00.30’’ S, 72°03’58.67’’ W) N = 30; Carlos III Island, Strait of Magellan (53°38’55.41’’ S, 72°15’31.04’’ W) N = 20; Port Famine, Strait of Magellan (53°36’34.07’’ S, 70°55’53.40’’ W) N = 50; Otway Sound, Strait of Magellan (52°56’13.10’’ S, 71°11’39.07’’ W) N = 30; Chabunco, Strait of Magellan (52°59’14.66’’ S, 70°48’44.43’’ W) N = 30; Laredo Bay, Strait of Magellan (52°56’59.14’’ S, 70°48’03.96’’ W) N = 50; Possession Bay, Strait of Magellan (52°13’55.50’’ S, 69°17’50.71’’ W) N = 30; Santa María Bay, Tierra del Fuego (53°19’29.86’’ S, 70°22’34.30’’ W) N = 60; Caleta River, Tierra del Fuego (53°51’45.32’’ S, 70°19’54.11’’ W) N = 60; Pía Fjord, Beagle Channel (54°49’36.81’’ S, 69°39’11.31’’ W) N = 4 0; Gar ib a ldi F j or d, Beag l e C h anne l (54°43’20.63’’ S, 69°57’48.27’’ W) N = 30; Wulaia Bay (54°59’20.30’’ S, 68°09’02.97’’ W) N = 40; Tekenika Bay (55°03’24.66’’ S, 68°07’52.22’’ W) N = 30; Orange Bay (55°27’21.44’’ S, 68°04’02.33’’ W) N = 30; Virginia Bay, Beagle Channel (54°54’16.95’’ S, 67°56’05.35’’ W) N = 40; Puerto Williams, Beagle Channel (54°56’04.95’’ S, 67°36’48.33’’ W) N = 26; Lapataia Bay, Beagle Channel (54°50’58.94’’ S, 68°28’41.95’’ W) N = 40; Hookers Point, Falkland / Malvinas Islands (51°42’09.60’’ S, 57°46’07.49’’ W) N = 50.

Shell: Shell shape and sculpture are very variable (de Aranzamendi et al., 2009) (Fig. 5A–C). The species exhibits a conical morphology, dorsally raised shell, which is thick and non-translucent (Fig. 5A–F). The anterior part of the animal is laterally compressed (Fig. 5D–F). It has a large shell (maximum length 120 mm), which has a medium profile. The apex is located at the anterior 30–40% of the shell’s length (Fig. 5A–F). All the slopes of the shell are convex (Fig. 5A–C). The aperture is oval to oblong. The surface of the shell is sculptured with numerous broad radial ribs and clearly defined concentric growth lines from the central zone towards the margin. The margin of the shell margin is highly crenulated. The external coloration of the shell is very variable across its distribution (pale reddish, brown, green with a bronze apex, grey, brown). The primary and secondary ribs are dark brown with clearer interspaces. The internal part of the shell has a soft metallic grey/brown interior with dark lines corresponding to external colour patterns, bordered by a white/brown halo.

External anatomy: The ventral area of the foot is grey and the epipodial fringe is recognizable. The mantle fold is thick and cream-coloured. The mantle tentacles are in an alternated series of three shorter pigmented ones (white/black/white) and a black longer one (Fig. 5G). The cephalic tentacles are dorsally pigmented with a black line (Fig. 5G).

Radula: See Valdovinos & Rüth (2005) (Fig. 5H).

Distribution: Magellanic province. Pacific Patagonia: from Guarello Island (50°S) to Cape Horn. Atlantic Patagonia: Tierra del Fuego. Falkland/ Malvinas Islands (Fig. 5I).

Habitat: Medium and low intertidal, subtidal rocky ecosystem between 0 and 40 m depths.

Comments: Our extensive sampling effort across Pa c i f i c Pa t a g o n i a s u g g e s t s t h a t N. d e a u r a t a occurs in this region from Guarello Island (50°S) to Cape Horn. In the Atlantic coast this species was reported north up to Mar del Plata province (Morris & Rosenberg, 2005). However, according to de Aranzamendi et al. (2009) the distribution of the species in the Atlantic is restricted to Tierra del Fuego. This species is also abundant in the Falkland/ Malvinas Islands. Molecular analyses suggest that N. deaurata represents a single genetic unit along Pacific (González-Wevar et al., 2011a) and Atlantic (de Aranzamendi et al., 2009, 2011) Patagonia. Molecular and geometric morphometric comparisons (González-Wevar et al., 2011a) showed that N. fuegiensis is a synonym of N. deaurata. Similarly, molecular analyses indicate that N. delicatissima represents particular morphotypes of N. deaurata (contra de Aranzamendi et al., 2009). Molecular analyses (unpublished data) indicate that N. deaurata exhibits marked levels of population genetic differentiation between Patagonia and the Falkland/ Malvinas Islands.