Oviposition and Embryonic Development in the Volutid Snail Adelomelon ancilla

ZABALA, S.; AVERBUJ, A; SANCHEZ ANTELO, C. J. M. ; PENCHASZADEH, P. E.; BIGATTI, G.

MALACOLOGIA

INST MALACOL

Lugar: Philadelphia; Año: 2015 vol. 58 p. 337 - 347

0076-2997

Intracapsular embryonic development is common in marine gastropods. In many species,embryos obtain nutrition during ontogeny by ingesting substances contained in the intracapsularfluid. South American volutids spawn egg capsules containing relatively few eggs,and development is entirely intracapsular, with young hatching as crawl-away juveniles.The spawning habits, egg capsules morphology and embryonic development of the SouthAmerican volutid Adelomelon ancilla is described in this work. Egg capsules of A. ancilla (n= 42) contained 3.0 ± 1.4 (mean ± SD) embryos with a range of 1?6 eggs or embryos. Theembryonic morphological changes and body spiralization occur simultaneously with embryofeeding. All embryos within a single egg capsule shared the same developmental stage. Noevidence of cannibalism or intracapsular competition was found, suggesting that food is nota limiting resource as in other volutid species. Estimated intracapsular developmental timevaried between five and six months (between 12?14°C). The long developmental time andlow number of embryos inside the egg capsules, together with late reproductive maturity andlongevity of adult individuals, reinforce the statement that the neogastropod Adelomelon ancillais a fragile resource that must be conserved in Argentinean benthic communities.