In molluscs the majority of marine specres is oviparous, whereas viviparity is frequently found among freshwater inhabitants. Here some findings from limnic gastropods are discussed and their evolutionary implications outlined. Recent studies reveal that live-bearing strategies have not only evolved repeatedly and independently among limnic gastropods, but also within lirnnic Cerithioidea, a diverse and speciose caenogastropod superfamily. Some of its constituent taxa evolved breeding along separate evolutionary avenues, involving distinct morphological structures (uterine brood sacs vs. subhaemocoelic brood pouches) and life-history strategies including nourishment of the brood via matrotrophy, as found in some species of Thiaridae s.str. It is concluded that (i) a uterine viviparous strategy, as found in lacustrine taxa from Lake Tanganyika (Laztigeria, Tiphobin), Lake Biwa in Japan (Senisul.cospirn) and from the central lakes on the Indonesian island of Sulawesi (Tylomelanin), evolved several times in para1le1, and (ii) that the subhaernocoelic brood pouch also derived convergently at least in the marine Planaxidae, some SE Asian Pachychilidae and the Thiaridae s.str., while the mesopodial brood pouch of the Tanganyikan paludomid Tangnnyicia rufofilosahas to be considered again an independently evolved structure.

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Nederlandse Malacologische Vereniging

M. Glaubrecht. (2006). Independent evolution of reproductive modes in viviparous freshwater Cerithioidea (Gastropoda, Sorbeoconcha) - a brief review. Basteria, 70(Suppl. 3), 23–28.