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UBC Theses and Dissertations

A numerical revision of the genus Ochotona (Lagomorpha:Mammalia) and an examination of its phylgenetic relationships Weston, Marla Lynn


The genus Ochotona is revised using numerical techniques on 42 craniometric measurements. As a result of this revision 18 extant species are recognized: 0. alpina, 0. collaris, 0. curzoniae, 0. daurica, 0. erythrotis, 0. kamensis, 0. koslowi , 0. ladacensis, 0. lama, 0. macrotis, 0. pallasi, 0. princeps, 0. pusilla, 0. roylei, 0. rufescens, 0. rutila, 0. thibetana and 0. thomasi. A description is given for each species as well as its original reference, synonymies, univariate statistics for the 42 craniometric measurements and a general description of the animal and its habitat. A skull representative of each species and maps outlining general ranges are also presented. Results of linear discriminant function analyses indicate an affinity of species from similar habitats. Phylogenetic relationships among species are discussed, and a cladogram is presented. Changes in overall size dominate the cladogram, with small size appearing to be the plesiomorphic state. Some fossil ochotonid groups are also examined, although the measurement sets used were greatly reduced due to the fragmentary nature of the fossil material. The reduced measurement sets do not appear to be diagnostic of taxonomic differences, but they do appear to be reflective of habitat differences. As a result, the ochotonids may prove to be useful indicators of paleoenvironments. Range reduction due to the influence of climate and competition is also discussed, as is the trend toward an overall increase in body size.

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