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July 6, 2007
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The taxonomic status and species limits of the South African-endemic rodent species Otomys saundersiae were revised using G-banding karyotypic analysis, assessment of pelage colour and craniodental traits, multivariate analysis of eight cranial distance measurements, and geometric morphometric analysis of 11 landmarks of the dorsal image of the skull. In the Western Cape, the recognized subspecies Otomys saundersiae karoensis differed in karyotype from sympatrically-occurring populations of O. irroratus (cytotype "C") in having six (as opposed to four) pairs of biarmed chromosome pairs and in the absence of pair number 14. Discriminant analysis of linear craniometric variables in positively identified (karyotyped) samples of Otomys irroratus and Otomys s. karoensis separated the two species without any overlap, as did pelage colour and certain qualitative cranial characters such as nasal angle; such clear-cut differences however were not apparent between unkaryotyped samples of O. s. saundersiae and O. irroratus from the Eastern Cape. Centroid size (from geometric morphometric analysis of cranial landmarks) was significantly correlated with both non-affine and affine components of skull shape, indicating strong allometric effects. Both cranial shape and size differed significantly between Western Cape O. s. karoensis and O. irroratus ; size, but not shape, varied significantly between Eastern Cape O. s. saundersiae and O. irroratus . Within both currently recognized species, significant geographical differences in cranial shape were detected between eastern and western Cape populations occupying distinct ecological biomes. Problems with defining species limits in this complex case were discussed with reference to available data and alternative species concepts.
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July 6, 2007
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There are currently six species of Micronycteris (sensu stricto) recognized in Venezuela, of which three have pale venters: M. homezi , M. minuta and M. schmidtorum . Since the original description of M. homezi as a subspecies of M. megalotis (based on the presence of a cutaneous fossa in the interauricular region), this taxon has not appeared in checklists for Venezuelan mammal inventories due to confusion and uncertainty related to the original description. However, it was recently reconsidered as a valid taxon on the basis of an additional series of males collected in French Guiana, Guyana, and Brazil. The examination of a larger number of specimens of Micronycteris collected in Venezuela (73 of them within the pale venter group), allows us to reject the cutaneous fossa as a valid character to diagnose M. homezi , suggesting that the name homezi represents a junior synonym of M. minuta . Among the arguments supporting this statement are: 1) the discovery of a cutaneous fossa in two congeneric forms ( M. megalotis and M. microtis ); 2) the existence of histological evidence verifying the presence of this structure (incipiently developed) in specimens assignable to M. minuta ; 3) the development of the fossa only in adult males (associated with a hypertrophy of the interauricular band); and 4) the similarity, in both chromatic and morphological features of Venezuelan specimens assignable to either M. minuta or M. homezi . The presence of a developed cutaneous fossa only in some adult males, as well as its correlation with the growth of the interauricular band and the modification of histological components could be the result of hormonal effects influenced by social rank or reproductive condition. Both structures are elements of a coordinated system, whereby the interauricular band is responsible for the production of sebaceous substances associated with the cutaneous fossa.
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July 6, 2007
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The Maulino forest, located at the coastal range of south central Chile, has been severely disrupted by intense human activities. Currently, landscape is dominated by large extensions of plantations of Monterrey pine, where remnants of native forest are immersed. Here, we assess consequences of Maulino forest fragmentation and habitat replacement upon small mammal fauna. We describe habitat characteristics, small mammal's composition and abundance in native forests (fragmented and continuous), but also in Pinus plantation. Population and body condition were compared among habitats, along with movement among native and Pinus forests. Higher species richness was found in continuous forest comprising Abrothrix longipilis, A. olivaceus, Oligoryzomys longicaudatus, Irenomys tarsalis, Geoxus valdivianus, Rattus rattus, Octodon bridgesi, Thylamys elegans , and Dromiciops gliroides . Higher abundance was observed in fragmented forest and Pinus plantations, where A. longipilis, A. olivaceus, O. longicaudatus , and T. elegans accounted for 80% of total captures. Population structure and body size were not affected negatively by fragmentation and habitat replacement, although habitat characteristics differed among surveyed habitats. Fragmentation of Maulino forests seems to have a significant impact on overall small mammal's richness, threatening the persistence of rare taxa of small mammals. Conservation and management practices are discussed to favor protection of this highly endangered habitat.
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July 6, 2007
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Small mammal communities were studied in four tropical habitats (dry thorn, dry and moist deciduous, and semi-evergreen forests) in Mudumalai Wildlife Sanctuary, southern India. Species composition, community structure, and population variables of small mammals in these habitats were examined. The relationship between small mammal community structure and select habitat variables was also examined. Six species of rodents and one insectivore were represented by 396 captures of 195 individuals out of a total of 7,425 trap nights (5.3% capture rate). Small mammals showed distinct distribution patterns across habitat types. Community structure, species richness, species diversity, relative abundance, and biomass varied across habitats, with each type having a different dominant species. Cremnomys blanfordi , which was the most abundant species, comprised 39%, Mus platythrix 29%, Rattus rattus 12%, M. musculus 9%, Tatera indica 5%, Suncus montanus 5%, and Platacanthomys lasiurus 1% of captures. Deciduous forest habitats supported the highest abundance and biomass of small mammals. However, based on the distinct distribution patterns, all four forest types are believed to be important for maintaining the local diversity of small mammal populations. Small mammal abundance was positively correlated with habitat heterogeneity. Although the community structure of small mammals is broadly determined by habitat structure, the specific microhabitat preferences of individual species could not be determined from these data.
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July 6, 2007
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Discriminant functions were constructed using external and cranial measurements to distinguish the six species of Myotis that occur in the southeastern United States. Twenty-three morphological characters were measured from 161 specimens of Myotis . Differences among species for morphological characters were examined using analysis of variance and discriminant analysis. A bootstrap procedure was used to validate the final discriminant model using all six species. Differences were observed among species for all 23 characters measured in univariate tests, but the range of values for most species overlapped the range of other species. Bootstrap analyses indicated that our discriminant functions constructed using both external and cranial measures allowed correct identification of 99.4% of specimens examined. Discriminant models constructed using only cranial characters permitted correct identification of 96.9% of specimens examined. Univariate analyses were not reliable because variation within species prevented unambiguous identification of any species based on a single character. However, Myotis species in the southeastern United States can be distinguished with a high level of accuracy using multivariate techniques when a sufficient number of measurements are used.
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July 6, 2007
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This paper present species records and inferable habitat preferences of a total of 35 bat species in 25 genera that were captured during three separate studies on the Potaro Plateau, western Guyana. One, Carollia castanea , is a new country record. Reproductive data is presented for seven species. Measurements and habitat data given for Platyrrhinus aurarius , a little-known species. The composition of the Potaro Plateau bat community is contextualized by comparison with 13 other sites in the north-east South America. A map shows all known bat collection localites in Guyana, for which a gazetteer provides supporting information.
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July 6, 2007
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Activity rhythms and movement patterns of Eurasian badgers ( Meles meles Linnaeus, 1758) inhabiting a cork oak woodland in SW Portugal are described. Twenty months of radio-tracking data for six individuals are presented. Badgers showed crepuscular or nocturnal activity, generally starting after sunset and ending before sunrise, being active on average for 8.26 hours per day. There was some seasonal variation in these parameters, but there was no evidence of any effect due to sex or moonlight. Nevertheless, wind speed seems to be associated with wide-ranging movements. No significant correlation was found between the onset of activity and sunset or between cessation of activity and sunrise. On average, badgers travelled 4378 m per night. Males usually had more extensive movements than did females, probably because maternal behaviour restricted female ranging. The mean distance between setts used on consecutive days was 295 m, and differed seasonally, being greater in spring 2000/2001 and summer 2000. Badgers inhabiting the cork oak woodland of our study area revealed lower sett fidelity than reported for their northern counterparts, especially those of lowland England. Only on 36% of occasions did they come back to sleep in the same sett, with females returning more often to the same den. The mean number of consecutive days spent in a sett was higher in spring and lower in summer.
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July 6, 2007
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Reliable information on abundance of the ocelot ( Leopardus pardalis ) is scarce. We conducted the first camera-trap study in the northern part of the Pantanal wetlands of Brazil, one of the wildlife hotspots of South America. Using capture-recapture analysis, we estimated a density of 0.112 independent individuals per km 2 (SE 0.069). We list other mammals recorded with camera traps and show that camera-trap placement on roads or on trails has striking effects on camera-trapping rates.
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