The arvicoline rodent Microtus is represented in the Irvington fauna by 72 specimens. The majority of these are isolated molars. Lower first molars are diagnostic and clearly identifiable as Microtus specimens with five closed triangles. No other arvicolines are present in the fauna. Morphological variation in the sample is present, but not extensive. Morphological features permitting species-level identification are lacking, and no species assignation can be supported with the available data. Changing perspectives on Pleistocene biochronology and reinterpretation of several purported early records of Microtus indicate that the Irvington specimens of Microtus with five closed triangles are among the oldest recorded in North America. Chronological control is limited to paleomagnetic data that reveal that the Irvington fauna dates to somewhere between 0.78 Ma and somewhat older than 1.21 Ma. The uncertainty cannot be reduced based on current understanding of the taxonomic affinity and known temporal extent of other mammals from Irvington.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 26 • No. 2