Robert S. Hoffmann

A Guide to the Mammals of China

Edited by Andrew T. Smith & Yan Xie: A Guide to the Mammals of China is published by Princeton University Press and copyrighted,

Phylogeny and Evolutionary History of the Ground Squirrels (Rodentia: Marmotinae)

Although ground squirrels (Spermophilus) and prairie dogs (Cynomys) are among the most intensively studied groups of mammals with respect to their ecology and behavior, a well-resolved phylogeny has not been available to provide a framework for comparative and historical analyses. We used complete mitochondrial cytochrome b sequences to construct a phylogeny that includes all 43 currently recognized species in the two genera, as well as representatives of two closely related genera (Marmota and Ammospermophilus). In addition, divergence times for ground squirrel lineages were estimated using Bayesian techniques that do not assume a molecular clock. All methods of phylogenetic analysis recovered the same major clades, and showed the genus Spermophilus to be paraphyletic with respect to both Marmota and Cynomys. Not only is the phylogeny at odds with previous hypotheses of ground squirrel relationships, but it suggests that convergence in morphology has been a common theme in ground squirrel evolution. A well-supported basal clade, including Ammospermophilus and two species in the subgenus Otospermophilus, diverged from all other ground squirrels an estimated 17.5 million years ago. Between 10 and 14 million years ago, a relatively rapid diversification gave rise to lineages leading to marmots and to several distinct groups of ground squirrels. The Eurasian ground squirrels diverged from their North American relatives during this period, far earlier than previously hypothesized. This period of diversification corresponded to warming climate and spread of grasslands in western North America and Eurasia. Close geographic proximity of related forms suggests that most species evolved in or near their current ranges.

A Bivariate Home Range Model with Possible Application to Ethological Data Analysis

Although home range and ethological data are believed to be intimately related, they have usually been analyzed separately for lack of a practical method of analysis or reasonable model relating them. We briefly review the calculation of some basic home range statistics and modified methods for estimating home range characteristics. A bivariate normal model shows most promise for such use. The additional calculation of eight points on the confidence ellipses for the location points, and for the activity center facilitates graphic representation of these probability ellipses. A standardized distance, which takes into account home range characteristics, is calculated. We believe this standardized distance may be related to familiarity within the home range, and as such could be correlated with behavior.

Socioecology of Marmots: Female Reproductive Strategies

The relationship between female reproductive success and both spring food and hibernacula resources was examined in a high-altitude population of yellow-bellied marmots (Marmota flaviventris). The number of offspring a female weaned was significantly associated with the estimated number she could potentially produce, based on food resources. The pro- duction of young by these females is probably food limited to varying degrees. Hibernacula may be a restricted resource; young reared in an area without a hibernaculum were not re- captured as yearlings. Delaying pregnancy until forage is available fails as a strategy because young have insufficient time to accumulate fat for hibernation. Adult females deposit fat at a single maximum rate regardless of reproductive history; few females gain weight prior to weaning their young. In areas with short growing seasons, measured as the period during which nonreproductive adults gain weight, females may occasionally or regularly fail to re- produce in consecutive years. The short period of time following weaning may not permit the accumulation of fat sufficient to provide energy for hibernation, postemergence activity, and reproduction. The growth rate (g/day) of young marmots is greater at high than at intermediate elevations. This increase in growth rate warrants further examination of the hypothesis that increased sociality among marmots living in areas with short growing seasons is a response to decreased growth rates of young animals.

Habitat Overlap and Competitive Exclusion in Voles (Microtus)

A field study, designed to test the hypothesis that habitat segregation in sympatric populations of Microtus pennsylvanicus and M. mo-ntcrnus is due to competition, was conducted on the National Bison Range in western Montana between June 1961 and May 1962. Experimental reduction of the numbers of M. pennsylvanicus induced moveiments of M. montanus into the vacated habitat, forming the basis for acceptance of the hypothesis. The nature of the movements plus .reciprocal avoidance behavior of both species of voles during normal circumstances suggest that the voles conform to the principle of competitive exclusion. The. significance of niche overlap is stressed and its adaptive qualities are discussed.

G-band patterns as chromosomal markers, and the interpretation of chromosomal evolution in wild sheep (Ovis)

Хромосомы и Г-полосы диких баранов из Палеарктика и Неарктика были изучалы. ЕвропейскийOvis musimon (2n=54) и АзиатскийO. orientalis (2n=54) имели кариотипы и Г-полосы трех пар две-плеуных аутосом одинаковый и этими Северо-АмериканогоO. canadensis mexicana (2n=54) ВO. musimon x O. canadensis Φ1иΦ2 гибриды гомологи которые составляли три иары две-плечных аутосом были легко олоэнаванны и были неразличимые. Изучениэ меиосис в Φ2 гибриде показало 27 бивалентых. Эволюционное зхачение гомологическиых две-плечных в баранах через Голарктик ыыло обсужденно.

Pattern Analysis of Acoustical Behavior in Four Species of Ground Squirrels

Acoustical behaviors of Spermophilus armatus, S. columbianus, S. elegans, S. richardsonii , and S. elegans × S. richardsonii hybrids were studied in an area of sympatry in southwestern Montana. Calls, categorized as chirps, churrs, squeals, growls, and teeth-clatters, were described in detail; further distinctions were noted for some taxa. Audiospectrograms were coded into two-dimensional arrays for correlation, and subsequent cluster analysis of call syllable patterns determined both within-call structure, and phenetic relationships between species. Tests to determine whether chirp, churr, and preface syllables paralleled systematic relationships were inconclusive but chirp calls seemed to be convergent where species were sympatric while churr calls seemed unaffected.

System Atics of the Holarctic Chipmunks (Tamias)

Electrophoretic data for 20 proteins were obtained from 17 species of chipmunks, including all three presently recognized subgenera. Average heterozygosity was higher than for ground squirrels ( Spermophilus ) but was generally within the range reported for other rodents; Tamias minimus , however, had a higher heterozygosity value than almost any other rodent species. Cladistic analyses of the electrophoretic data resulted in species groupings which differed from traditional analyses of morphological data. The species T. Sibiricus and T. striatus were grouped together, separate from all other chipmunks, thereby contradicting traditional supra-specific classifications. We recognize one genus ( Tamias ) with two subgenera, Tamias (composed of Sibiricus and striatus ) and Neotamias with five species groups. A hypothesis concerning dispersal in the ancestral chipmunk lineage was formulated and a phylogram constructed on the basis of cladistic and biogeographic analyses. Multivariate analyses then were conducted on cranial and body measurements of 53 taxa of chipmunks, representing all recognized species and subgenera. Variation among individual taxa was detected in both general size and cranial shape. Phenetic morphological relationships among the chipmunks were ascertained by cluster analysis. The proposed phylogenetic groupings were compared with the morphological groupings in an assessment of divergent and convergent evolution within the genus.

Chromosomes and systematics of some North American species of the genus Marmota (Rodentia: Sciuridae).

Die Zahl der diploiden Chromosomen vonMarmota caligata undM. flaviventris ist 42 in Bevölkerungen der nördlichen und südlichen Verbreitungsgebiete beider Spezies. Ein Vergleich zwischen den bisher veröffentlichten Informationen überMarmota-Chromosomen mit Angaben über ihre Morphologie, Ekologie, Zoogeographie legt nahe, dass die ursprüngliche Chromosomenzahl 2n 38–40 war.

G-band patterns, chromosomal homologies, and evolutionary relationships among wild sheep, goats, and aoudads (mammalia, artiodactyla)

Хромосмы и Г-полосы диких баранов, Африканских гривистых баранов, и безоаровых козлов изучалы.Capra aegagrus из Ирана показало 2n=60, и кариотип содержит 29 пары акроцентических аутосом. Шесть из этих аутосомов одинаковый с трёх пар двеплечных аутосом у диких баранов и домашых овец (2n=54).Ammotragus lervia иOvis vignei (2n=58) имели кариотнпы и Г-полосы пар две-плыечных аутосом неразличимый.