Late Pleistocene Horses of Dry Cave, Eddy County, New Mexico

Abstract
Equus conversidens Owen, E. niobrarensis Hay, E. occidentalis Leidy referred, E. scotti Gidley referred, and a small zebrine horse are recognized from late Pleistocene deposits of Dry Cave, southeastern New Mexico. Equus midlandensis Quinn is synonymized with E. niobrarensis; New Mexican specimens previously recognized as E. scotti are identified as E. niobrarensis. Cluster analysis of measurements of single elements, acting on matrices of taxonomic distances, appears to allow assignment of intermingled elements to species more successfully than do traditional comparative methods. Cluster analysis based on correlation matrices of limb proportions indicates close similarity of E. niobrarensis to E. przewalskii Poliakoff. Dental characters and cluster analysis suggest that E. conversidens belongs to the subgenus Hemionus or was derived from that subgenus.