Dental morphology of the Lesser Bamboo Rat, Cannomys badius (Rodentia, Spalacidae).

Raquel López-Antoñanzas

doi:10.3897/zookeys.228.3826

Abstract

Cannomys and Rhizomys are the sole living genera of the tribe Rhizomyini (Rhizomyinae, Spalacidae, Rodentia), known in the fossil record since the Late Miocene. The dental morphology of fossil Rhizomyini has been described in detail but until recently such descriptions were unavailable for extant species. A detailed account of the morphology and dental wear pattern of the cheek teeth of Cannomys badius is provided here based on the examination of museum specimens. Three stages of wear are recognized. Cannomys shares with Rhizomys the synapomorphy of having a mesolophid that is a long continuation of the protoconid on the first lower molar. There are significant differences between these taxa, such as the much smaller size of the cheek teeth and the trilophodont dental pattern of the M2, M3, and m2 in Cannomys.

Highlights

The subfamily Rhizomyinae (Spalacidae, Rodentia) is known in the fossil record since the Oligocene
The Asian bamboo rats belong to the tribe Rhizomyini, whereas Tachyoryctes is the only extant representative of the Tachyoryctini (Flynn 2009; LópezAntoñanzas et al in press)
The upper molars of Cannomys badius show unilateral hypsodonty, with crowns higher lingually than labially. m1 has four roots, the anterolabial one being the Dental morphology of the Lesser Bamboo Rat, Cannomys badius (Rodentia, Spalacidae) 71

Summary

Introduction

The subfamily Rhizomyinae (Spalacidae, Rodentia) is known in the fossil record since the Oligocene. It is represented by three modern genera: the Asian bamboo rats Rhizomys (a trispecific genus) and Cannomys (monospecific) and the African mole rats Tachyoryctes. The latter genus is considered bispecific by some authors (Missone 1971, Rahm 1980, Bucher 1982, Corbet and Hill 1991, Beolchini and Corti 2004), but this. It is known to live in a wide variety of habitats, from bamboo forest to cultivated land and other modified areas (IUCN 2010)

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