Abstract—Observations of web spinning behavior in Costa RicanDinopissp. reveal the same behaviors synapomorphic for orb weavers: specifically frame, radius, non‐sticky spiral construction, and sticky spiral construction, as well as more detailed motor patterns. Dinopids are therefore highly derived orb weavers, although the behavioral data do not conclusively indicate whether they are more closely related to the uloborid or araneoid orb weavers. A cladogram of dinopids, uloborids, and araneoids is presen