Gustafson R G, Littlewood D T J, Lutz R A
Biol Bull. 1991 Feb;180(1):34-55. doi: 10.2307/1542427.
Egg capsules from three different prosobranch gastropods were retrieved from the Galapagos Rift and Juan de Fuca Ridge deep-sea hydrothermal vent fields. The morphology of these capsules and their excapsulated embryos and larvae are described and illustrated. Based on their capsule type and the protoconch morphology of their contained larvae, 29 lenticular capsules from the Galapagos Rift could be attributed to a provisionally described neogastropod turrid, Phymorhynchus sp. But 3 inflated, triangular capsules from the Galapagos Rift, and 56 different egg capsules from the Juan de Fuca Ridge, each shaped like an inflated pouch, could not be unambiguously assigned to a member of the known vent gastropod fauna. The mode of development and potential for dispersal is inferred from egg capsule type, the number of embryos per capsule, and protoconch characters comparable to those of confamilial shallow-water gastropods for which the type of development is known. These criteria and a comparison to the known juvenile shell morphology of Phymorhynchus sp., suggest that, after encapsulation, this species develops planktotrophically and is capable of long-range dispersal. Similar evidence suggests that the larvae contained in the inflated triangular capsules from the Galapagos Rift may also develop planktotrophically after hatching; but the larvae in the pouch-like egg capsules from the Juan de Fuca Ridge probably develop non-planktotrophically without a dispersal stage. These developmental patterns are characteristic of shallow-water members of the systematic groups to which these species belong, indicating, as previous studies have shown, that vent gastropods can persist in these patchy, ephemeral environments in the absence of unique adaptations allowing dispersal between active hydrothermal sites.
从加拉帕戈斯裂谷和胡安德富卡海岭深海热液喷口区采集到了三种不同前鳃腹足类动物的卵囊。描述并展示了这些卵囊及其孵化出的胚胎和幼虫的形态。根据卵囊类型及其所含幼虫的原壳形态，来自加拉帕戈斯裂谷的29个透镜状卵囊可归为一种暂定为新腹足目塔螺科的Phymorhynchus sp.。但来自加拉帕戈斯裂谷的3个膨胀的三角形卵囊以及来自胡安德富卡海岭的56个形状各异的卵囊（每个都像一个膨胀的袋子），无法明确归为已知的喷口腹足类动物群中的某个成员。根据卵囊类型、每个卵囊中胚胎的数量以及与已知发育类型的同科浅水腹足类动物可比的原壳特征，推断出发育模式和扩散潜力。这些标准以及与Phymorhynchus sp.已知幼体壳形态的比较表明，该物种在被包裹后进行浮游性发育，并且能够进行远距离扩散。类似的证据表明，来自加拉帕戈斯裂谷的膨胀三角形卵囊中所含的幼虫孵化后可能也进行浮游性发育；但来自胡安德富卡海岭的袋状卵囊中所含的幼虫可能不进行浮游性发育，也没有扩散阶段。这些发育模式是这些物种所属系统类群的浅水成员所特有的，正如先前研究所示，这表明在没有允许在活跃热液区之间扩散的独特适应性的情况下，喷口腹足类动物能够在这些零散、短暂的环境中生存。
