Seed dispersal anachronisms: rethinking the fruits extinct megafauna ate

BACKGROUND: Some neotropical, fleshy-fruited plants have fruits structurally similar to paleotropical fruits dispersed by megafauna (mammals >103 kg), yet these dispersers were extinct in South America 10–15 Kyr BP. Anachronic dispersal systems are best explained by interactions with extinct animals and show impaired dispersal resulting in altered seed dispersal dynamics. METHODOLOGY/PRINCIPAL FINDINGS: We introduce an operational definition of megafaunal fruits and perform a comparative analysis of 103 Neotropical fruit species fitting this dispersal mode. We define two megafaunal fruit types based on previous analyses of elephant fruits: fruits 4–10 cm in diameter with up to five large seeds, and fruits >10 cm diameter with numerous small seeds. Megafaunal fruits are well represented in unrelated families such as Sapotaceae, Fabaceae, Solanaceae, Apocynaceae, Malvaceae, Caryocaraceae, and Arecaceae and combine an overbuilt design (large fruit mass and size) with either a single ...研究背景：部分新热带区肉质果植物的果实结构，与由巨型动物（体重超过103千克的哺乳动物）传播的古热带区果实相似，但这类种子传播者已于距今1.0万至1.5万年前在南美洲灭绝。此类滞后型种子传播系统的最佳解释为其与已灭绝动物的互作关系，且该类系统会出现传播能力受损的情况，进而改变种子传播动态。 研究方法/主要结果：本研究提出了巨型动物传播果实（megafaunal fruits）的可操作定义，并针对符合该传播模式的103种新热带区果实物种开展比较分析。基于此前针对象类传播果实的分析，我们界定出两类巨型动物传播果实：一类直径为4至10厘米，含至多5枚大型种子；另一类直径大于10厘米，包含大量小型种子。这类果实广泛存在于多个非近缘的植物科中，如山榄科（Sapotaceae）、豆科（Fabaceae）、茄科（Solanaceae）、夹竹桃科（Apocynaceae）、锦葵科（Malvaceae）、玉蕊科（Caryocaraceae）以及棕榈科（Arecaceae），兼具“过度构建”的构型特征（即较大的果实质量与尺寸），且要么具单枚……