Evolutionary history of marine mollusks in warm periods

本文以软体动物（特别是菊石类和鹦鹉螺类）化石标本为基础，分析了其多样性和幼体大小的演化历史。鹦鹉螺幼体的大小在白垩纪末期的大灭绝中没有变化。对古生代和中生代幼体大小的分析表明，从古生代到中生代幼体大小逐渐增大，表明同域物种形成是其宏观演化的主导过程。

Based on fossil specimens of mollusks(especially ammonoids and nautiloids), their evolutionary history of diversity and hatchling sizes was analyzed. The hatchling sizes in nautiloids show no change across the end-Cretaceous mass extinction. The analyses of hatchling sizes during Paleozoic and Mesozoic demonstrated that the hatchling sizes increased from Paleozoic toward Mesozoic, suggesting that sympatric speciation was a plausible dominant process of their macroevolution.