Nacella, DELESSERTI

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 : 320

publication ID

https://doi.org/ 10.1093/zoolinnean/zly067

publication LSID

lsid:zoobank.org:pub:68738EE0-509B-4201-854C-2ABB41662357

DOI

https://doi.org/10.5281/zenodo.5718921

persistent identifier

https://treatment.plazi.org/id/C55987A1-8108-FFC1-3398-F9480B98F8B2

treatment provided by

Carolina

scientific name

Nacella
status

 

NACELLA DELESSERTI View in CoL ( PHILIPPI, 1849)

( FIG. 9 View Figure 9 )

Patella delesserti Philippi, 1849: 9 , pl. 1, fig. 5.

Patella ferruginea Reeve, 1854: 425 View in CoL , pl. XVII, fig. 40a–c. Nacella (Patinigera) delesserti View in CoL – Powell, 1973: 196; Cantera & Arnaud, 1985: 34.

Nacella delesserti View in CoL – Blankley & Branch, 1984: 171; Blankley & Branch, 1985: 259; Hodgson & Bernard, 1989: 145; González-Wevar et al., 2016b: 77; 2017: 863.

Material studied: Trypot Beach, Marion Island (46°52’33.91’’ S, 37°51’51.40’’ E) N = 50; Ships Cove, Marion Island (46°51’16.22’’ S, 37°50’42.36’’ E) N = 40; Crozet Islands (46°25’34.25’’ S, 51°51’42.50’’ E) N = 50.

Shell: The shell shape and sculpture are relatively constant ( Fig. 9A–C View Figure 9 ). The species exhibits a conical morphology, dorsally raised, with a very thick and non-translucent shell ( Fig. 9A–F View Figure 9 ). The anterior part of the animal is laterally compressed ( Fig. 9D–F View Figure 9 ). It has a medium-sized shell (maximum length 80 mm) and exhibits a variable profile. The apex is situated at the anterior 25–35% of the shell’s length ( Fig. 9D–F View Figure 9 ). All the slopes of the shell are convex ( Fig. 9A–C View Figure 9 ). The aperture of the shell is oval. The surface of the shell exhibits low radial folds and lamellar growth lines. The margin of the shell is highly crenulated. The external coloration of the shell is relatively constant in the species: grey to white, with dark (brown and black) primary radial ribs. The internal part of the shell has a soft metallic-white coloration, with dark lines corresponding to external colour patterns, bordered by a white/brown halo.

External anatomy: The ventral area of the foot is black and the epipodial fringe is highly recognizable. The mantle fold is thick and dun-brown coloured. The mantle tentacles are in alternate series of three shorter pigmented ones (white/black/white) and black longer one ( Fig. 9G View Figure 9 ). The cephalic tentacles are dorsally pigmented with a black line ( Fig. 9G View Figure 9 ).

Radula: The first lateral teeth are set close together on the anterior edge of the basal plates, long and very sharp, with two cusps. The second laterals are broader, wider spaced, with four very sharp cusps ( Fig. 9H View Figure 9 ).

Distribution: Marion, Prince Edward and Crozet Islands ( Fig. 9I View Figure 9 ).

Habitat: High and medium intertidal rocky ecosystem between 0 and 30 m depths.

Comments: Nacella delesserti was first reported at Crozet Islands by Cantera & Arnaud (1985), a finding we confirm here. These authors also reported the species from South Georgia, but our sample of>150 individuals consisted only of N. concinna . Zelaya (2005) also failed to find N delesserti at South Georgia. Hence, we consider N. delesserti to be restricted to Marion and Crozet Islands. Phylogenetic reconstructions placed N. delesserti as the sister species of N. concinna , their separation occurring around 0.35 Mya ( González-Wevar et al., 2017). The presence of N. delesserti at sub-Antartctic Marion and Crozet Islands is thus the result of evolutionarily recent long-distance dispersal from maritime Antarctica. Nacella delesserti showed very low levels of genetic diversity that constitute evidence of recent postglacial expansion in Marion Island. Due to the exceptional high density and biomass of N. delesserti on Marion Island rocky shores, it plays an important role in the organization of intertidal and shallowwater benthic communities ( Blankley & Branch, 1985).

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

SubClass

Patellogastropoda

Order

Patellida

SuperFamily

Lottioidea

Family

Nacellidae

Loc

Nacella

González-Wevar, Claudio A., Hüne, Mathias, Rosenfeld, Sebastián, Nakano, Tomoyuki, Saucède, Thomas, Spencer, Hamish & Poulin, Elie 2019
2019
Loc

Nacella delesserti

Gonzalez-Wevar CA & Hune M & Segovia NI & Nakano T & Spencer HG & Chown S & Saucede T & Johnstone G & Mansilla A & Poulin E 2017: 863
Gonzalez-Wevar CA & Hune M & Rosenfeld S & Saucede T & Feral J-P & Mansilla A & Poulin E 2016: 77
Hodgson A & Bernard R 1989: 145
Blankley WO & Branch GM 1985: 259
Blankley WO & Branch GM 1984: 171
1984
Loc

Patella ferruginea

Cantera JR & Arnaud PM 1985: 34
Powell AWB 1973: 196
Reeve LA 1854: 425
1854
Loc

Patella delesserti

Philippi RA 1849: 9
1849
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