SGER: Predation in evolution: paleobiological consequences of cidaroid predation on crinoids

进化中的捕食：来自澳大利亚吕宋岛和新西兰渐新世的证据K. 鲍米勒捕食被普遍认为是自然选择的一个重要因素，研究化石记录中的捕食者-猎物相互作用使我们能够评估其进化影响。 大量的研究致力于探索捕食在海百合生态学和进化中的作用。 例如，有人认为，在过去的100万年里，有柄海百合迁移到深水中（Bottjer Jablonski 1988）是捕食压力增加的结果，特别是来自贝壳破碎鱼（Meyer Macurda 1977; Meyer 1985; Oji 1996）。 相比之下，有人认为，今天在浅水中茁壮成长的无柄comatulid海百合的成功是由于他们有能力应对捕食压力（Meyer Macurda 1977）。海百合和comatulids在处理捕食压力方面的差异通常归因于后者脱落和再生身体部位的能力和运动能力。然而，最近发现，今天？在有柄海百合中占优势的一类，异海百合，也能够快速爬行（Baumiller Messing 2007），这是一种通常与无柄comatulid海百合有关的特征。也有研究表明，这些异海百合科动物容易被类囊海胆捕食（Baumiller等人，2008年）。 响应于与类西达菌素的相互作用，异百合科昆虫脱落茎的锚定端并爬离被脱落的茎部分占据的类西达菌素。 这个吗？蜥蜴？的尾巴？逃跑策略不仅将一系列行为特征（茎脱落和爬行）与捕食联系起来，而且表明在评估海百合的生态和进化历史时需要考虑底栖捕食者，如cidaroids。本研究的主要目的是确认的鲁棒性的直接代理cidaroid捕食海百合（咬痕和骨折模式）。 这将涉及到研究活的cidaroids如何用牙齿和肠道处理海百合物质。 这将在澳大利亚的吕宋岛研究站（LIRS）进行实验。 此外，在LIRS，其他潜在的捕食者，如鱼类和甲壳类动物的海百合材料的处理，将探讨这些不同的捕食者是否留下独特的签名对他们的海百合猎物的骨骼。 研究的实验部分之后将探索化石记录，以寻找这种捕食者-猎物相互作用的历史证据。 具体而言，茎海百合的Kokoamu砂岩（渐新世，南岛，新西兰）将研究的证据，cidaroid损害。 之所以选择科科阿穆砂岩，是因为它含有丰富的海百合柱以及海百合科的遗迹，Histocidaris，最近在其肠道中发现了海百合成分的分类单元。 如果成功，这项研究的结果将作为追求更大目标的基础：（1）通过检查已知与雪海胆共存的海百合茎的遗骸，探索这种相互作用在地质时期的历史，（2）分析海百合的形态，以获得与茎脱落和爬行相关的特征，以及（3）在这些背景下研究海百合的多样性趋势？逃避？特征和互动频率。

Predation in evolution: paleobiological consequences of cidaroid predation on crinoids.Evidence from Lizard Island, Australia and the Oligocene of New ZealandT. K. BaumillerPredation is generally recognized as an important agent of natural selection and the study of predator-prey interactions in the fossil record allows us to evaluate its evolutionary impact. A large body of work has been devoted to exploring the role of predation in crinoid ecology and evolution. For example, it has been argued that the displacement of stalked crinoids to deep water over the past ~100my (Bottjer & Jablonski 1988) was the result of increased predation pressure, especially from shell-crushing fish (Meyer & Macurda 1977; Meyer 1985; Oji 1996). In contrast, it has been suggested that the success of the stalkless comatulid crinoids that today thrive in shallow water is due to their ability to deal with predation pressure (Meyer & Macurda 1977). The differences in handling predation pressure by stalked crinoids and comatulids have generally been attributed to the ability to shed and regenerate body parts and locomotory abilities of the latter. However, recently it has been discovered that today?s dominant group of stalked crinoids, the isocrinids, are also capable of rapid crawling (Baumiller & Messing 2007), a trait generally associated with stalkless comatulid crinoids. It also has been shown that these isocrinids are subject to predation by cidaroid sea urchins (Baumiller et al. 2008). In response to the interaction with a cidaroid, isocrinids shed the anchored end of the stalk and crawl away from the cidaroid which is preoccupied with the shed stalk portion. This ?lizard?s tail? strategy of escape not only links a set of behavioral traits (stalk shedding and crawling) to predation, but suggests that benthic predators, such as cidaroids, need to be considered in assessing the ecological and evolutionary history of crinoids. The major goal of this study is to confirm the robustness of a direct proxy for cidaroid predation on crinoids (bite marks and fracture patterns). This will involve studying how living cidaroids process crinoid material with their teeth and in their gut. This will be done experimentally at the Lizard Island Research Station (LIRS), Australia. Also at LIRS, the processing of crinoid material by other potential predators, such as fish and crustaceans, will be explored to see whether these different predators leave unique signatures on the skeletons of their crinoid prey. The experimental portion of the study will be followed by exploring the fossil record for historical evidence of this predator-prey interaction. Specifically, stalked crinoids of the Kokoamu Sandstone (Oligocene; South Island, New Zealand) will be studied for evidence of cidaroid damage. The Kokoamu Sandstone was chosen because it contains abundant crinoid columnals as well as remains of the cidaroid, Histocidaris, the very taxon which in the Recent was found with crinoid elements in its gut. If successful, the results of this study will serve as the basis for pursuing larger goals: (1) to explore the history of this interaction through geologic time by examining remains of crinoid stalks from localities where they are known to co-occur with cidaroid echinoids, (2) analyze the morphology of crinoids for traits associated with stalk shedding and crawling, and (3) examine diversity trends of crinoids in the context of these ?escapability? traits and the frequency of interaction.