Eurypterids are generally considered to comprise a mixture of active nektonic to nektobenthic predators and benthic scavenger-predators exhibiting a mode of life similar to modern horseshoe crabs. However, two groups of benthic stylonurine eurypterids, the Stylonuroidea and Mycteropoidea, independently evolved modifications to the armature of their anterior appendages that have been considered adaptations toward a sweep-feeding life habit, and it has been suggested the evolution toward sweep-feeding may have permitted stylonurines to capture smaller prey species and may have been critical for the survival of mycteropoids during the Late Devonian mass extinction. There is a linear correlation between the average spacing of feeding structures and prey sizes among extant suspension feeders. Here, we extrapolate this relationship to sweep-feeding eurypterids in order to estimate the range of prey sizes that they could capture and examine prey size in a phylogenetic context to determine what role prey size played in determining survivorship during the Late Devonian. The mycteropoid Cyrtoctenus was the most specialized sweep-feeder, with comblike appendage armature capable of capturing mesoplankton out of suspension, while the majority of stylonurines possess armature corresponding to a prey size range of 1.6–52 mm, suggesting they were suited for capturing small benthic macroinvertebrates such as crustaceans, mollusks, and wormlike organisms. There is no clear phylogenetic signal to prey size distribution and no evolutionary trend toward decreasing prey sizes among Stylonurina. Rather than prey size, species survivorship during the Late Devonian was likely mediated by geographic distribution and ability to capitalize on the expanding freshwater benthos.

中文翻译：

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辨别扫食广翅目动物的饮食：在系统发育背景下评估猎物大小对晚泥盆纪大灭绝期间生存的重要性

Eurypterids 通常被认为是由活跃的内生到内生的捕食者和底栖的清道夫-捕食者的混合物，表现出类似于现代马蹄蟹的生活方式。然而，两组底栖 stylonurine eurypterids，Stylonuroidea 和 Mycteropoidea，独立进化出对其前附肢电枢的修改，这些修改被认为是适应扫食的生活习惯，并且有人认为向扫食的进化可能已经允许 stylonurines 捕捉较小的猎物物种，并且可能对泥盆纪晚期大灭绝期间类真菌的生存至关重要。在现存的悬浮喂食器中，喂食结构的平均间距与猎物大小之间存在线性相关性。这里，我们将这种关系推断为扫食的广翅目，以估计它们可以捕获的猎物大小范围，并在系统发育背景下检查猎物大小，以确定猎物大小在确定晚泥盆纪生存期中所起的作用。类真菌鲫鱼是最专业的扫掠式喂食器，具有梳状附件电枢，能够捕获悬浮中的浮游生物，而大多数 stylonurines 具有对应于 1.6-52 毫米猎物尺寸范围的电枢，这表明​​它们适合捕获小型底栖大型无脊椎动物，例如甲壳类动物、软体动物和蠕虫状生物。没有明确的猎物大小分布的系统发育信号，也没有在 Stylonurina 中减少猎物大小的进化趋势。不是猎物的大小，晚泥盆世的物种生存可能是由地理分布和利用不断扩大的淡水底栖生物的能力介导的。