The Effects of Cenozoic Global Change on Squirrel Phylogeny

Abstract

By modifying habitats and creating bridges and barriers between landmasses, climate change and tectonic events are believed to have important consequences for diversification of terrestrial organisms. Such consequences should be most evident in phylogenetic histories of groups that are ancient, widespread, and diverse. The squirrel family (Sciuridae) is one of very few mammalian families endemic to Eurasia, Africa, and North and South America and is ideal for examining these issues. Through phylogenetic and molecular-clock analyses, we infer that arrival and diversification of squirrels in Africa, on Sunda Shelf islands, across Beringea, and across the Panamanian isthmus coincide in timing and location with multiple well-documented sea-level, tectonic, and paleontological events. These precise correspondences point to an important role for global change in the diversification of a major group of mammals.

Molecular phylogeny and biogeography of woolly flying squirrel (Rodentia: Sciuridae), inferred from mitochondrial cytochrome b gene sequences

“…Flying squirrels are a well-supported monophyletic group and could be separated as two major groups (Mercer and Roth, 2003;Thorington and Darrow, 2000). Pteromys and Petaurista share similar morphological characteristics with Eupetaurus (McKenna, 1962;Mein, 1970;Thorington and Darrow, 2000), but Eupetaurus is closely related to Aeromys, Pteromys, Belomys, and Trogopterus according to the combined molecular data of the nuclear gene coding for interphotoreceptor retinoid-binding protein (IRBP) and mitochondrial 12S and 16S ribosomal DNA (Mercer and Roth, 2003).…”

“…Pteromys and Petaurista share similar morphological characteristics with Eupetaurus (McKenna, 1962;Mein, 1970;Thorington and Darrow, 2000), but Eupetaurus is closely related to Aeromys, Pteromys, Belomys, and Trogopterus according to the combined molecular data of the nuclear gene coding for interphotoreceptor retinoid-binding protein (IRBP) and mitochondrial 12S and 16S ribosomal DNA (Mercer and Roth, 2003). Although we were not able to include Aeromys in our analyses because of its rarity in collections, several other members of each major group were used to reconstruct phylogenetic trees, including Pteromys, Trogopterus, Belomys, Petaurista, Glaucomys, and Hylopetes (Table 1).…”

“…Molecular characters indicate that flying squirrels are a well-supported monophyletic group and show a sistergroup relationship with the tribes Sciurini and Tamiasciurini (Herron et al, 2004;Mercer and Roth, 2003;Steppan et al, 2004). In order to increase the reliability of tree topology, the tree squirrels Sciurus aestuans and Tamiasciurus hudsonicus were selected as the outgroup taxa for phylogenetic reconstruction.…”

“…Flying squirrels are monophyletic and were distinguished as two major groups (Mercer and Roth, 2003;Thorington and Darrow, 2000). This view has led to the widespread acceptance of this relationship, which in turn has had a tremendous influence on the interpretation of flying squirrel evolution in genetics and morphology.…”

“…Here we discuss the taxonomic status of the Eupetaurus populations in Pakistan and southwestern China to determine how much variety exists within the genus Eupetaurus along its extensive distribution. Petaurista, Pteromys, Trogopterus, and Belomys, which are closely related to Eupetaurus (McKenna, 1962;Mein, 1970;Mercer and Roth, 2003;Thorington and Darrow, 2000), were included for reconstructing the phylogeny of Eupetaurus.…”