Collaborative Research: Hermits, Kings, and Convergence: Integrating Molecules and Morphology to Study the Phylogenetic Relationships of the Anomura (Crustacea Amoura)

9615461只坎宁安寄居蟹最出名的是用空蜗牛壳作为庇护所。大多数将寄居蟹定义为一个群体的形态特征似乎都是对不对称卷曲的壳的适应。然而，数量惊人的物种使用蜗牛壳以外的物体作为庇护所，或者根本不使用庇护所。这些寄居蟹往往比它们使用贝壳的亲戚更对称，而那些不使用庇护所的寄居蟹也往往会发生癌症；也就是说，腹部缩小并被塞在一个宽阔的、重装甲的甲壳下。这样的螃蟹可能不会被认为是寄居蟹，但可能会被错误地归入其他蟹类。由于缺乏可靠的系统发育史，寄居蟹的壳层使用进化、不对称性和癌变等长期存在的问题无法得到解决。在这个合作研究项目中，克利夫·坎宁安(分子序列)和艾伦·哈维(形态学)将整合大量的形态和分子数据，为寄居蟹及其近亲(即Anomura)生成一个强大的系统发育图。根据这个系统发育，坎宁安和哈维将确定1)异形甲壳类动物有多少次独立地采用了使用贝壳的习惯；2)不使用栖息地的寄居蟹的癌变形态是从使用贝壳的寄居蟹的不对称形态进化而来的，还是相反；3)寄居蟹的存在和栖息地的存在和类型影响了癌变和不对称形态的哪些特征。

9615461 CUNNINGHAM Hermit crabs are best known for using empty snail shells as shelters. Most morphological features that define hermit crabs as a group seem to be adaptations to the asymmetrically coiled shell. A surprising number of species, however, use objects other than snail shells for shelters, or use no shelter at all. These hermit crabs tend to be more symmetrical than their shell-using relatives, and those that use no shelters are also often "carcinized"; that is, the abdomen is reduced and tucked under a wide, heavily armored carapace. Such crabs may not be recognized as hermit crabs, but may instead be wrongly placed in other crab groups. The lack of a reliable phylogenetic history has made it impossible to resolve long-standing questions concerning the evolution of shell use, asymmetry and carcinization in hermit crabs. In this collaborative research project, Cliff Cunningham (molecular sequences) and Alan Harvey (morphology) will integrate extensive morphological and molecular data to generate a robust phylogeny for the hermit crabs and their allies (i.e., the Anomura). With this phylogeny, Cunningham and Harvey will determine 1) how many times anomuran crustaceans independently adopted the shell-using habit; 2) whether the carcinized morphology of nonshelter-using hermit crabs evolved from the asymmetrical morphology of shell-using hermit crabs, or vice versa; 3), which features of both the carcinized and asymmetrical morphologies are influenced by the presence and type of shelter used by hermit crabs.