Development and early life history of three temperate Australian species of Conus (Mollusca: Gastropoda)

Abstract

The temperate Australian Conus species C. dorreensis, C. klemae, and C. anemone spawn in January at Rottnest Island, Western Australia. Their reproductive and developmental patterns closely resemble those of tropical Indo-Pacific congeners with respect to the relationships of egg size, number of eggs per egg capsule and egg mass, size and form at hatching, and presence or absence of planktonic larval stage. All three species deposit flask-shaped egg capsules on the undersides of flat rocks, and C. dorreensis also oviposits in clumps of the calcareous red alga Jania. The small (152 µm) eggs of C. dorreensis hatch in 12-17 days as small (ca. 250 µm) planktotrophic veligers. C. klemae eggs are medium-sized (280 µm); they hatch as well developed planktonic veligers with shells 450 µm. C. anemone eggs are larger than those of all but one known Indo-Pacific species and are ovoid (790x710 µm), and the number produced is smaller than in any known Indo-Pacific species. C. anemone hatchlings are benthic veliconchas with shells 1.6 mm long. Except for the large size and small number of C. anemone eggs, as far as could be determined the three species fit the patterns of reproductive biology and early life history attributes demonstrated in Indo-Pacific congeners. These include similar spawning time, nest sites, and relations of egg size with pre-hatching development time, size and stage at hatching, and presence or absence of planktonic larval stage.