MOLLUSCA OF SOUTHERN CHILE 



139 



Records. Stations 1, 6. Elsewhere El Lagartillo (Panama) to 

 GolfoCorcovado(01sson, 1961; Soot- Ryen, 1959), extended south- 

 ward by the present record. Range: 8°N^6°S. 



Remarks. This is a commercial edible species; the 1997 catch 

 was 4316 tonnes (SERNAP, 1998). 



Family VENERIDAE 



Venus antiqua King & Broderip, 1832 

 (Figure 51) 



Venus antiqua King & Broderip, 1832: 336. Fischer- Piette, 1975: 

 24-25 (synonymy). 



Protothaca antiqua - Carcelles, 1950: 80, pi. 5, fig. 86. 



Ameghinomya antiqua - Soot-Ryen, 1959: 54-55, pi. 3, figs 22, 23. 

 Osorio & Bahamonde, 1970: 202. Dell, 1971: 175-176 (syn- 

 onymy). Osorio, Atria & Mann, 1979: 29-30, fig. 32. Bernard, 

 1983: 51 (synonymy). 



Protothaca antiqua antiqua - Herm, 1969: 123, pi. 10, figs 1-A, pi. 

 11, figs 1,2. 



Venus antiqua antiqua - Osorio, Frassinetti & Bustos, 1 983: 49-56, 

 figs 1-11 (synonymy). 



Description. Shell to 76 mm; rounded, inflated; sculpture of 

 numerous strong radial ribs, crossed by fine concentric lamellae, the 

 lamellae more strongly raised on anterior and posterior slopes; 

 lunule in front of beaks outlined by deeply incised line; hinge strong, 

 three cardinal teeth in each valve; margin crenulated internally; 

 pallial sinus small; colour cream to pale brown, sometimes marked 

 by tessellated or fine radial chevron pattern in small shells, interior 

 cream. 



HABITAT. On silty sand at low water on sheltered beach; common 

 embedded in gravel under stones in rock pools in low eulittoral on 

 moderately sheltered rocky shore; abundant in gravel in shallow 

 channel with strong tidal currents, 1.5 m depth at high tide; dredged 

 from 7-15 m depth on bottoms of cobbles and silt; found living at 

 salinities down to 15— 20%o. This is a dominant member of intertidal 

 and shallow subtidal soft-bottom communities in southern Chile, 

 and is typically found shallowly buried in mixed silty and stony 

 substrates (Urban, 1994) and in gravelly muddy sand (Clasing, 

 Brey, Stead, Navarro & Asencio, 1994). It has been recorded down 

 to depths of 18-25 m (Soot-Ryen, 1959; Dell, 1971) and 65 m 

 (Ramorino, 1968). 



RECORDS. Stations 1, 7, 14, 15, 22, 25, 26. Elsewhere Callao 

 (Peru) to Tierra del Fuego (Soot-Ryen, 1959; Osorio et al., 1983). 

 Range: 12-55°S. 



REMARKS. This species shows variability in shell outline and 

 degree of development of sculpture. It is an important edible species 

 and is the major component of 'almejas' (including other large 

 venerid bivalves), of which the 1997 harvest was 12475 tonnes, 

 largely from Isla Chiloe (SERNAP, 1998). It is an abundant compo- 

 nent of shell middens on Isla Traiguen and freshly dead shells 

 indicate that collection for food continues on a small scale in the 

 area. We do not advocate use of the subspecific epithet, since the 

 description of the only 'subspecies' (P. antiqua tongoyensis Herm, 

 1969) does not conform to the requirements of either geographical 



or stratigraphic separation from the typical form. We follow 

 Fischer-Piette (1975) in assigning this species to the genus Venus, 

 and we confirm that the date of publication of the original descrip- 

 tion by King & Broderip is 1832. 



Retrotapes exalbidus (Dillwyn, 1817) 



(Figure 5 J) 



Venus exalbida Dillwyn, 1817:170. 



Samarangia exalbida - Carcelles, 1944: 287, pi. 12, figs 93, 94. 



Carcelles, 1950: 80, pi. 5, fig. 87. 

 Eurhomalea exalbida - Soot-Ryen, 1959: 59. Dell, 1964: 219 



(synonymy). Osorio & Bahamonde, 1970: 203. Fischer-Piette & 



Vukadinovic, 1977: 106-107 (synonymy). Osorio, Atria & Mann, 



1979: 30-31, fig. 34. 

 Retrotapes exalbida - del Rio, 1997: 80-82, figs 22, 23, 41. 



Description. Shell to 85 mm (to 106 mm, NHM); large, heavy 

 venerid; sculptured by raised concentric lamellae, regularly-spaced 

 1-2 mm apart on young shells, becoming crowded on larger shells, 

 lunule in front of beaks outlined by groove; internal margin smooth; 

 hinge with 3 strong cardinal teeth in each valve; colour cream to 

 brownish, interior white. 



Habitat. Two dead valves dredged from 10-15 m on bottoms of 

 cobbles, gravel and coarse sand. It has been found living in the low 

 intertidal zone in the Magellan Strait (Urban & Tesch, 1996), 

 Carcelles (1950) gave a depth range of 5-115 m, and Dell (1964) 

 recorded specimens from 147 m in the Falkland Islands. 



Records. Stations 7, 14. Elsewhere I. Chiloe to Cape Horn 

 (Carcelles & Williamson, 1951; Fischer-Piette & Vukadinovic, 

 1977). Range: 42-56°S. 



Remarks. The shell outline and regularity of sculpture are both 

 variable in this species (Carcelles, 1944; Dell, 1964). This species 

 has recently been assigned to the new genus Retrotapes by del Rio 

 (1997); we note that since the Latin noun tapes is masculine, 

 Retrotapes should take the same gender. It is an edible species, a 

 component of 'almejas' (see V; antiqua). 



Tawera gayi (Hupe, 1854) 



(Figure 5H) 



Venus gayi Hupe, 1854: 337, malacologia pi. 6, fig. 5a-c. 

 Clausinella gayi -Carcelles, 1944: 287, pi. 13, figs 97, 98. Carcelles, 



1950: 80, pi. 5, fig. 88. Soot-Ryen, 1959: 58, pi. 3, figs 26. 27 



(synonymy). Herm, 1969: 126, pi. 12, figs 7, 8. 

 Tawera gayi - Osorio & Bahamonde, 1970: 203. Dell, 1971: 175. 



Fischer-Piette & Vukadinovic, 1977: 39^10, fig. 8 (synonymy). 



Bernard, 1983: 53 (synonymy). 



Description. Shell to 12 mm (to 39 mm, Carcelles, 1944); rounded 

 outline; sculptured by fine concentric ridges, of which a few become 

 irregular and anastomose on anterior and posterior slopes, lunule in 

 front of beaks outlined by groove; inner margin crenulated; hinge 

 with three strong cardinal teeth in each valve; colour cream to pale 

 brown, interior white. 



Habitat. Two dead valves dredged from 10-15 m on bottoms of 

 cobbles, gravel and coarse sand. Recorded from the tidal zone and 



Fig. 7 Scanning electron micrographs of Gastropoda and Bivalvia. A. lothia coppingeri. B. Puncturella (Puncturella) conica. C. Nodilittorina araucana. 

 D. Eitmetula pulla. E. Glypteuthria meridionalis. F. Homalopoma cwminghami. G. Nucula (Nucula) pisum. H, I. Lasaea miliaris. J. Carditella tegulata. 

 K. Carditopsis flabellum flabellum. (All specimens from study area; NHM collection). 



