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首页> 外文期刊>Marine biology >Early life history of two closely related gastropods, Rissoa auriscalpium and Rissoa italiensis (Caenogastropoda : Rissoidae)
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Early life history of two closely related gastropods, Rissoa auriscalpium and Rissoa italiensis (Caenogastropoda : Rissoidae)

机译：两种密切相关的腹足动物的早期生活史，即Rissoa auriscalpium和Rissoa italiensis（Caenogastropoda：Rissoidae）

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A comparative analysis of the early life history of two common gastropod forms living on the leaves of the Mediterranean seagrass Posidonia oceanica has been carried out, taking into account timing and phases of development. The forms have a different distribution along a depth transect at Ischia Island (Gulf of Naples, Italy), the more squat and ribbed being mainly present between 1 and 15 m depth, with a maximum density at 3 m, the other, between 10 and 30 m. They were distinguished as sibling species, Rissoa italiensis (Verduin, 1985) and Rissoa auriscalpium (L., 1758), on the basis of protoconch size. However, to date, the systematic relationship between them is still unclear. Electrophoretic studies showed lower genetic distance between the two forms along the transect, than among populations from other locations in the Mediterranean Sea. R. auriscalpium have planktonic development, with a higher number of smaller eggs, while R. italiensis have an intracapsular veliger, with hatching juveniles. As for the patterns of development, while the same stages are recognizable in the two gastropod forms up to the formation of the veliger, several differences in timing occur, along with differences in growth and death rates of the embryos. R. auriscalpium hatches as a veliger at the first phase of torsion, about 10 days after spawning, while R. italiensis completes its torsion and metamorphosis within the capsule, and then hatches as a juvenile about 18 days after spawning. The time of encapsulation is what seems to lead to similar developmental sequences with different reproductive patterns and ecological roles, depending on the organization of the elements in the capsule.
机译：考虑到发展的时机和阶段，对生活在地中海海草波塞冬尼亚的叶子上的两种常见腹足纲动物的早期生活史进行了比较分析。这些形态在伊斯基亚岛（意大利那不勒斯海湾）的深度剖面上具有不同的分布，深蹲和肋状分布主要在1至15 m深度之间，最大密度在3 m处，其他在10至30 m之间。 30米根据原生海螺的大小，它们被区分为兄弟姐妹种，意大利扁桃（Verduin，1985）和澳大利亚扁桃（L.，1758）。但是，到目前为止，它们之间的系统关系仍然不清楚。电泳研究表明，沿着该样带的两种形式之间的遗传距离比地中海其他地方的种群之间的遗传距离低。尖头金龟具有浮游生物的发育，卵较小，数量更多，而意大利扁头金龟的包囊内有幼虫。至于发育的模式，虽然在两个腹足纲的形式直至形成雌蕊之间都可以识别出相同的阶段，但在时间上会出现一些差异，以及胚胎的生长和死亡率的差异。产卵后约十天，金龟头龟在扭动的第一阶段孵化为食肉，而在壳内，Italiensis完成其扭转和变态，然后在产卵后约十八天孵化为幼鱼。包囊的时间似乎导致具有不同生殖模式和生态作用的相似发育序列，这取决于胶囊中元素的组织。

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