 Because of their historically mixed assemblages which included tarsiers and close relatives of primates, both Prosimii and Strepsirrhini have been considered wastebasket taxa for "lower primates". Regardless, the strepsirrhine and haplorrhine clades are generally accepted and viewed as the preferred taxonomic division. Yet, tarsiers still closely resemble both strepsirrhines and simians in different ways, and since the early split between strepsirrhines, tarsiers, and simians is ancient and hard to resolve, a third taxonomic arrangement with three suborders is sometimes used: Prosimii, Tarsiiformes, and Anthropoidea. More often, the term "prosimian" is no longer used in official taxonomy, but is still used to illustrate the behavioral ecology of tarsiers relative to the other primates.
