Differentiating Microtus xanthognathus and Microtus pennsylvanicus Lower First Molars Using Discriminant Analysis of Landmark Data

• Published in: Journal of Mammalogy
• Main Author: Wallace, Steven C.
• Format: Text
• Language: English
• Published: Oxford University Press 2006
• Subjects: Feature Articles; taiga
• Online Access: http://jmammal.oxfordjournals.org/cgi/content/short/87/6/1261; https://doi.org/10.1644/05-MAMM-A-209R3.1

The distinct ecological requirements of Microtus xanthognathus (yellow-cheeked vole or taiga vole) and M. pennsylvanicus (meadow vole) warrant accurate discrimination of their remains in studies of paleoecology and past biogeographical shifts. An occlusal length of the lower 1st molars (ml) that is >3.2 mm for M. xanthognathus is the method most frequently used to separate these 2 taxa in archaeological and paleontological samples. However, these measurements alone are unreliable because some specimens of M. pennsylvanicus overlap smaller individuals of M. xanthognathus in size. Therefore, I created and tested a morphometric technique that discriminates Recent lower 1st molars (mis) of M. pennsylvanicus from those of M. xanthognathus , and is applicable to other taxa (both modern and fossil). Despite overlapping occlusal length, my discriminant function based on landmark data correctly classified 100% ( n = 53) of Recent mis from the 2 taxa and 97.7% (43 of 44) of (assumed) mis of M. pennsylvanicus from an archaeological site from about AD 1200 in central Nebraska. This landmark scheme is applicable to fossil and modern Microtus worldwide.