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

寄居蟹以使用空蜗牛壳作为庇护所而闻名。大多数将寄居蟹定义为一个群体的形态学特征似乎是对不对称盘绕壳的适应。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有壳的亲戚更对称，而那些没有庇护所的寄居蟹也经常“致癌”；也就是说，它的腹部缩小了，塞在一个宽大的、全副武装的甲壳下。这些螃蟹可能不被认为是寄居蟹，而是可能被错误地放在其他螃蟹群中。由于缺乏可靠的系统发育史，因此无法解决寄居蟹的外壳使用、不对称和癌变等长期存在的问题。在这个合作研究项目中，Cliff Cunningham（分子序列）和Alan Harvey（形态学）将整合广泛的形态学和分子数据，为寄居蟹及其盟友（即Anomura）生成一个强大的系统发育。根据这种系统发育，坎宁安和哈维将确定：1)异源甲壳类动物有多少次独立地养成了吃壳的习惯；2)非居壳寄居蟹的癌化形态是由居壳寄居蟹的不对称形态进化而来的，还是相反；(3)寄居蟹形态的癌变和不对称的特征受寄居蟹所使用的庇护所的存在和类型的影响。

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.