Archboldomys(Muridae: Murinae) Reconsidered: A New Genus and Three New Species of Shrew Mice from Luzon Island, Philippines

Danilo S Balete,Timothy Sosa,Sharon A Jansa,Melizar V Duya,Phillip A Alviola,Eric A Rickart,Mariano Roy M Duya,Lawrence R Heaney

doi:10.1206/3754.2

Abstract

ABSTRACT Shrew mice of the genus Archboldomys are poorly known members of an endemic clade of vermivorous/insectivorous murid rodents confined to Luzon Island, Philippines. Three species of these small, ground-living, diurnal mice were previously known, all from a handful of specimens from a few localities. The pattern of morphological and genetic differentiation among additional specimens of shrew mice from our recent field surveys in the Central Cordillera and Sierra Madre mountains of Luzon document the presence of two distinct species groups within Archboldomys as previously defined, as well as three new species. Gene-sequence data from the mitochondrial cytochrome b and nuclear IRBP genes confirm the existence of six distinct species, but also show that Archboldomys, as previously defined, is composed of two clades that are not sister taxa. Reevaluation of the presumed morphological synapomorphies among these shrew mice, together with analyses of karyological and gene-sequence data, support the follo...

Highlights

Shrew mice of the genus Archboldomys are part of one of the oldest known radiations of murid rodents in the Philippines, and provide important insights into the dynamics of mam¬ malian diversification on isolated oceanic islands (Jansa et al, 2006)
Together with the shrew rats Chrotomys and Rhynchomys, their closest relatives, they form a clade of terrestrial murid rodents adapted to feeding on earthworms and soft-bodied invertebrates on the cool, damp forest floor of montane and mossy forest on the mountaintops of Luzon Island in the northern Philippines (Balete et al, 2011; Duya et al, 2011; Jansa et al, 2006; Rickart et al, 1991, 2011a)
Molecular sequence data has failed to support the monophyly of Archboldomys; the two “species groups” are strongly supported as members of the Chrotomys Division, we find that Archboldomys, as currently defined, is paraphyletic and includes two divergent genera: Archboldomys and Soricomys, new genus, described below

Summary

Introduction

Shrew mice of the genus Archboldomys are part of one of the oldest known radiations of murid rodents in the Philippines, and provide important insights into the dynamics of mam¬ malian diversification on isolated oceanic islands (Jansa et al, 2006). The results confirmed the phylo¬ genetic link of Archboldomys with the Chrotomys Division, but found evidence that a close relationship with Crunomys was ambiguous, with possible convergence of the two on a shrew¬ like (i.e., Soricidae-like) morphology and trophic adaptation This shrewlike morphology is associated with their heavy use of earthworms and other soft-bodied invertebrates captured in leaf litter (Rickart et al, 1991, 2011a; Heaney et al, 1999; Balete et al, 2011)

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Results

Conclusion