Victor E. Diersing

Systematics and Evolution of the Pygmy Shrews (Subgenus Microsorex) of North America

Morphological and zoogeographical data indicate that North American pygmy shrews are referable to the Holarctic genus Sorex and to the Nearctic subgenus Microsorex Coues, 1877. Microsorex has its closest affinities with the North American autochthonous subgenus Otisorex . These subgeneric relationships are represented in a phylogenetic classification. Univariate and multivariate analyses support the conclusion that the subgenus Microsorex is monotypic, containing the species Sorex hoyi . Five subspecies are recognized based on these analyses. Variation in the species is generally that of decreased overall size from north to south. In addition, there are several zones where the species exhibits a rapid change in size. These zones demarcate subspecies boundaries. There is no demonstrable secondary sexual variation and individual variation is slight. There are significant changes in the skull and in the head and body length with increased age. The roots of the first upper incisors grow continuously, thus farther separating the cingulum from the alveolus with increased age. The degree of separation between the cingulum and alveolus is used as the index to age. Wear on the first upper incisors is rapid. Their continued down and back growth is necessary for continued occlusion with the lower incisors.

Review of the Tassel-Eared Squirrels of the Subgenus Otosciurus

Geographic variation was studied throughout the range of Sciurus aberti . Sixteen external and cranial measurements were used in the analyses of 244 adults. All morphological data were treated by principal components and cluster analysis and by two bivariate analyses. Color was found to be highly variable within certain populations and was accordingly given low taxonomic value. Sciurus aberti consists of six valid subspecies, including S. a. kaibabensis . A diagnosis is given for each subspecies. Rivers and other areas of low relief act as boundaries separating subspecies.

SYSTEMATIC STATUS OF SYLVILAGUS BRASILIENSIS AND S. INSONUS FROM NORTH AMERICA

tropical eastern and southern Mexico southward through Panama. The Omilteme rabbit, S. insonus, is known only from the Sierra Madre del Sur of Guerrero, Mexico. At the turn of the century, our taxonomic knowledge of S. brasiliensis consisted of only two brief descriptions: that of Lepus brasiliensis var. gabbi (=S. brasiliensis gabbi) from Costa Rica (Allen, 1877); and Lepus truei (=S. brasiliensis truei) from Veracruz, Mexico (Allen, 1890). Later, Bangs (1901) described Lepus incitatus (=S. brasiliensis incitatus) from San Miguel Island, Panama, and Allen (1908) described Lepus gabbi tumacus (=S. brasiliensis tumacus) from Nicaragua. During this time, Nelson (1904) described Lepus insonus (=S. insonus) from Guerrero, Mexico. Nelson (1909) subsequently reviewed the cottontails of North America and recognized S. insonus and S. brasiliensis (=S. gabbi of Nelson) with three subspecies, truei, gabbi (with tumacus as a synonym), and incitatus. Since that time, two additional subspecies of S.

Taxonomic Status of Short-Tailed Shrews (Blarina) in Illinois

Five hundred and twenty-one short-tailed shrews, genus Blarina , from Illinois together with 125 from South Dakota, Iowa, Kentucky, Tennessee, and Ohio, were studied using multivariate analyses of morphometric characters. Two groups of shrews are readily distinguishable with no overlap in size. There are two places of sympatry in southern Illinois. The two groups represent the species Blarina brevicauda and Blarina carolinensis . Within the range of B. brevicauda , there is clinal variation from Ohio, across Illinois, to Iowa and South Dakota, but there is sufficient reason to recognize two subspecies, B. b. kirtlandi and B.b. brevicauda .

Revision of the Shrews Sorex merriami and a Description of a New Species of the Subgenus Sorex

One hundred and five specimens of S. merriami , including old and new records, were analyzed for nongeographic and geographic variation. Sorex merriami is monotypic. Comparisons of S. merriami with some specimens previously referred to S. vagrans from southern Arizona documents the presence of a new species from the Huachuca, Santa Rita, and Chiricahua mountains. Sorex vagrans is also known from the Chircahua Mountains. The new species was compared to other members of the subgenus Sorex , to which it belongs, and is most closely related to S. emarginatus from Jalisco, Mexico. Characters are given for recognition of the new species, S. merriami , and S. vagrans in Arizona.

Systematic status of the rabbits Sylvilagus brasiliensis and S. sanctaemartae from northwestern South America with comparisons to Central American populations

Using 26 cranial measurements, we conducted a morphometric study on 113 adult skulls of the currently recognized rabbits Sylvilagus brasiliensis and S. sanctaemartae from Colombia, Ecuador, and Peru. Five morphological groups are identified of which 4 warrant species-level recognition. North and west of the Andes, S. gabbi occupies the lowlands of northern Colombia and northwestern Ecuador. Sylvilagus sanctaemartae is morphologically indistinguishable from S. gabbi and is a synonym of it. Two species live in the Andes of Colombia: S. fulvescens in the Western and Central Andes and S. apollinaris in the Eastern Andes. East of the Andes, Sylvilagus brasiliensis defilippi is found in the tropical Orinoco and Amazon basins of Colombia, Ecuador, and Peru, and S. brasiliensis andinus occurs in the Andes of Ecuador. These 2 subspecies intergrade in the Amotape-Huancabamba Zone of extreme southern Ecuador and adjacent west-central Peru. The eastern distributional limit of S. b. defilippi outside the study area in South America is unknown. An additional 50 skulls of S. gabbi and 14 of S. dicei were examined from Costa Rica and Panama to compare with the rabbits from South America. The data show that S. gabbi exhibits no noticeable geographic variation from Central America to northern Colombia and northwestern Ecuador. Sylvilagus dicei from the Cordillera de Talamanca of Costa Rica and Panama is morphologically most similar to S. fulvescens from the Western and Central Andes of Colombia and they are likely closely related. Methods are presented to identify all taxa and the distribution of each taxon is provided. This taxonomic arrangement is based on few specimens. Accordingly, species boundaries and phylogenetic relationships should be tested by focusing future collecting and morphological and molecular research in high-priority areas such as: 1) along the Colombian–Ecuadorian border from the Pacific Coast, across the Andes into the Amazon Basin; 2) Amotape-Huancabamba Zone of Ecuador and Peru; and 3) Eastern Andes of Colombia.