Data and code for: The evolution of siphonophore tentilla for specialized prey capture in the open ocean

Predator specialization has often been considered an evolutionary ‘dead-end’ due to the constraints associated with the evolution of morphological and functional optimizations throughout the organism. However, in some predators, these changes are localized in separate structures dedicated to prey capture. One of the most extreme cases of this modularity can be observed in siphonophores, a clade of pelagic colonial cnidarians that use tentilla (tentacle side branches armed with nematocysts) exclusively for prey capture. Here we study how siphonophore specialists and generalists evolve, and what morphological changes are associated with these transitions. To answer these questions, we: (1) measured 29 morphological characters of tentacles from 45 siphonophore species, (2) mapped these data to a phylogenetic tree, and (3) analyzed the evolutionary associations between morphological characters and prey type data from the literature. Instead of a dead-end, we found that siphonophore speciali...捕食特化常被视为演化上的“死胡同”，这是由于整个生物体在形态与功能优化的演化过程中存在诸多约束限制。然而在部分捕食者类群中，这类演化改变仅局限于专门用于捕食的特化结构。这类模块化演化的最极端案例之一可见于管水母类（siphonophores）：它们是一类浮游群居刺胞动物（cnidarians），仅依靠触手小分支（tentilla，即带有刺细胞（nematocysts）的触手侧枝）完成捕食。本研究旨在探讨管水母类的特化捕食者与泛化捕食者类群的演化路径，以及伴随这类演化转变发生的形态学变化。为解答上述问题，我们开展了以下工作：（1）对45种管水母类的触手开展29项形态学性状测量；（2）将所得数据映射至系统发育树；（3）分析形态学性状与文献记载的猎物类型数据之间的演化关联。研究结果并未支持“死胡同”假说，反而发现管水母类的特化