Archonta: Overview

Introduction

The Archonta are a clade of arboreal mammals that includes the primates (Latin, primus - "first") and a number of smaller groups. In the past bats were included here as well on morphological grounds, but molecular phylogeny indicates that they are an unrealted group of mammals. We've placed a question mark next to them on the dendrogram above, to show the ambiguity caused by the disagrement between morphological and molecular evidence. The etymology of Archonta (from the Greek archon, ruler), as with Primate. is presumably a reference to the most successful Quaternary species of primate, a mostly morphologically generalised species distinguished by its bipedal stance, large cranium, and sophisticated tool-using abilities. In this unit however we consider the non-primate archontans, which include a diverse selection of shrew-, rodent-, lemur-, and flying fox- like gliding forms. Of these, the Plesiadapiformes were by far the most succesful during the Paleocene and early Eocene, and their later decline may be a result of the reise to prominance of rodents. Or perhaps more likely, given the non-competitive model (evident in the succesion of dynasties of Triassic archosaurs (Benton 1983), the Plesiadapiformes may have disappeared due to other factors, and the rodents simply radiated to fill the vacarted ecological niches.