Marine invertebrates can display several reproductive strategies, from external reproduction to parental care. Internal brooding is particularly relevant in harsh conditions, like Antarctic/sub-Antarctic waters and deep-sea, since it maximizes the survival of the young. Actinostola crassicornis is an abundant and widely distributed sea anemone from the southwestern Atlantic Ocean. It can be found all along the Argentinean sea down to 1200 m depth, usually in large numbers. It is a unique species in the area, since it is a large white brooding sea anemone. We studied 75 specimens collected by the O/V Walther Herwig and the O/V Puerto Deseado all along its distribution, from about 60 m to 800 m depth, in different seasons of the year. All the specimens were sexed, and the presence of free oocytes and juveniles inside the coelenteron were assessed. Large oocytes (over 500 μm) and juveniles were found in samples from most of the sampled months. We found a larger number of female specimens, and most of the brooding specimens were female. No early developmental stages were found smaller than a sea anemone with about 12 tentacles. We conclude that A. crassicornis reproduces continuously throughout the year and that although most of the juveniles were found in females, male specimens can breed. Brooding has great benefits in terms of protecting the offspring, since predation upon the juveniles is prevented, but dispersal of the offspring is low, shown by the aggregated distribution of the species.

中文翻译：

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在大西洋西南部的深海海葵 Actinostola crassicornis (Hertwig, 1882) (Cnidaria: Anthozoa: Actiniaria) 中孵化

海洋无脊椎动物可以展示多种繁殖策略，从外部繁殖到父母照顾。内部育雏在恶劣条件下尤其重要，例如南极/亚南极水域和深海，因为它可以最大限度地提高幼鱼的存活率。Actinostola crassicornis 是一种来自大西洋西南部的丰富且广泛分布的海葵。它可以在整个阿根廷海域找到，深达 1200 米，通常数量众多。它是该地区的独特物种，因为它是一种大型的白色育雏海葵。我们研究了 O/V Walther Herwig 和 O/V Puerto Deseado 收集的 75 个标本，它们分布在一年中的不同季节，从大约 60 m 到 800 m 深度。所有样本都进行了性别鉴定，并评估了腔肠内是否存在游离卵母细胞和幼体。在大多数采样月份的样本中发现了大卵母细胞（超过 500 μm）和幼虫。我们发现了更多的雌性标本，大多数育雏标本是雌性。没有发现比海葵更小的早期发育阶段，大约有 12 个触手。我们得出结论，A. crassicornis 全年持续繁殖，虽然大多数幼鱼是在雌性中发现的，但雄性标本可以繁殖。育雏在保护后代方面有很大的好处，因为可以防止对幼鱼的捕食，但从物种的总体分布情况可以看出，后代的扩散很低。没有发现比海葵更小的早期发育阶段，大约有 12 个触手。我们得出结论，A. crassicornis 全年持续繁殖，虽然大多数幼鱼是在雌性中发现的，但雄性标本可以繁殖。育雏在保护后代方面有很大的好处，因为可以防止对幼鱼的捕食，但从物种的总体分布情况可以看出，后代的扩散很低。没有发现比海葵更小的早期发育阶段，大约有 12 个触手。我们得出结论，A. crassicornis 全年持续繁殖，虽然大多数幼鱼是在雌性中发现的，但雄性标本可以繁殖。育雏在保护后代方面有很大的好处，因为可以防止对幼鱼的捕食，但从物种的总体分布情况可以看出，后代的扩散很低。