scholarly journals Comparative 2D-shape analyses of collared lemmings in the zone of possible sympatry between Dicrostonyx groenlandicus and Dicrostonyx richardsoni (Rodentia, Arvicolinae)

2020 ◽  
Vol 6 (4) ◽  
pp. 423-436
Author(s):  
Kamal Khidas ◽  
Elliott Andrew Schmidt ◽  
Dominique Fauteux
Keyword(s):  
Multivariate Analyses ◽  
Canadian Arctic ◽  
Morphological Differentiation ◽  
Taxonomic Status ◽  
Genetic Evaluation ◽  
Lake Area ◽  
Distribution Ranges ◽  
Dicrostonyx Groenlandicus ◽  
Baker Lake ◽  
Shape Analyses

Morphological differentiation and relationships among collared lemmings (Dicrostonyx Gloger, 1841) remain unclear. This issue is particularly important in the Kivalliq Region, Nunavut, Canada, where Dicrostonyx groenlandicus (Traill, 1823) and Dicrostonyx richardsoni Merriam, 1900 ranges overlap. Possible sympatry of both species obscures the taxonomic status of collared lemmings from this area. We compared 2D outline shapes of the skull and three upper molars of collared lemmings collected from seven areas of the Canadian Arctic, including specimens from the Baker Lake – Aberdeen Lake area, in the Kivalliq Region, and Dicrostonyx hudsonius (Pallas, 1778) as an outgroup. Multivariate analyses revealed two distinct groups when considering the molars: D. hudsonius, and the remainder of lemmings. Dicrostonyx richardsoni, D. groenlandicus, and the lemmings from the Baker Lake – Aberdeen Lake area showed significant differences, especially when considering skull shapes, thus suggesting three distinct groups. However, skull shapes proved inefficient in discriminating between species. These differences suggest that collared lemmings from the Baker Lake – Aberdeen Lake area may not be correctly assigned to either of the two species without further genetic evaluation. They also suggest that these lemmings should have a peculiar taxonomic status. Our study calls for further taxonomical investigations for collared lemmings from the overlapping distribution ranges of D. groenlandicus and D. richardsoni.

Differences in behavior help to explain lemming coexistence

2019 ◽  
Vol 100 (4) ◽  
pp. 1211-1220 ◽  
Author(s):  
Douglas W Morris ◽  
Angélique Dupuch ◽  
MaryJane Moses ◽  
Kaylee Busniuk ◽  
Helen Otterman
Keyword(s):  
Open Field ◽  
Exploratory Behavior ◽  
Behavioral Response ◽  
Habitat Preferences ◽  
Canadian Arctic ◽  
Field Tests ◽  
Repeated Testing ◽  
Dicrostonyx Groenlandicus ◽  
Components Analysis ◽  
Innate Behaviors

Abstract Collared (Dicrostonyx groenlandicus) and brown (Lemmus trimucronatus) lemmings coexist in tundra habitats across much of the middle and lower Canadian arctic. Their coexistence, and response to predation risk, appears mediated by behavior. We analyzed field-collected videos of open-field tests to assess potential differences in innate behaviors between the two species. Collared lemmings were less active and exhibited less exploratory behavior than did brown lemmings, which were more active under cover than in the open. Similar behaviors scaling along axes of activity and curiosity were revealed by principal components analysis. Each axis defined different aspects of brown lemming personality, but repeated testing of the same individuals yielded a striking dependence of their behavioral response on open-field treatments. Even so, the differences between species in behavior correlate well with their habitat preferences that resolve competition and govern their coexistence.

Geographical variation and taxonomy of the snail-eating snake Dipsas albifrons (Sauvage, 1884), with comments on the systematic status of Dipsas albifrons cavalheiroi Hoge, 1950 (Serpentes: Colubridae: Dipsadinae)

Zootaxa ◽  
2005 ◽  
Vol 1013 (1) ◽  
pp. 19 ◽  
Author(s):  
PAULO PASSOS ◽  
RONALDO FERNANDES ◽  
MARCOVAN PORTO
Keyword(s):  
Geographic Variation ◽  
Geographical Variation ◽  
Multivariate Analyses ◽  
Taxonomic Status ◽  
External Morphology ◽  
Island Population ◽  
Systematic Status ◽  
Qualitative Analyses

The taxonomic status of Dipsas albifrons is revised and geographic variation of external morphology and hemipenis are described. Multivariate analyses suggest that the pattern of geographical variation is correlated with gap sampling, probably indicating a northernward cline in segmental counts (mainly ventral and subcaudal scales). Quantitative and qualitative analyses reveal that the island population (Dipsas albifrons cavalheiroi) is not divergent from mainland populations and, herein, is considered a junior synonymy of Dipsas albifrons. A lectotype of Dipsas albifrons is designated.

Phylogeography, geographic variation, and taxonomy of the Bent-toed Gecko Cyrtodactylus quadrivirgatus Taylor, 1962 from Peninsular Malaysia with the description of a new swamp dwelling species

Zootaxa ◽  
2012 ◽  
Vol 3406 (1) ◽  
pp. 39 ◽  
Author(s):  
CHELSÉA B. JOHNSON ◽  
EVAN QUAH S. H. ◽  
SHAHRUL ANUAR ◽  
M. A. MUIN ◽  
PERRY L. WOOD, JR. ◽  
...  
Keyword(s):  
Molecular Phylogeny ◽  
Geographic Variation ◽  
Morphological Analysis ◽  
Morphological Differentiation ◽  
Taxonomic Status ◽  
Color Pattern ◽  
Peninsular Malaysia ◽  
Mean Differences

A review of the taxonomic status of the Bent-toed Gecko Cyrtodactylus quadrivirgatus Taylor, 1962 based on a molecularphylogeny, scalation, and color pattern analyses indicate that it is composed of a single, recently expanding, widespreadpopulation with weakly supported phylogeographic substructuring with no discrete morphological differentiation betweenpopulations. However, based on sampling, significant mean differences in selected scale counts occur between some pop-ulations. The molecular phylogeny and morphological analysis strongly indicate lineage independence between a subsetof individuals from the Bukit Panchor, Penang population and their closest relative C. pantiensis Grismer, Chan, Grismer,Wood & Belabut, 2008 from southern Peninsular Malaysia. Furthermore, the analyses indicate that the individuals of thissubset are conspecific and not part of C. quadrivirgatus as previously suggested. Additionally, this subset is morphologi-cally distinct from all other Sundaland species of Cyrtodactylus, and as such is described herein as Cyrtodactylus payacola sp. nov.

Geographic variability and taxonomy of the nose-horned viper, Vipera ammodytes (L. 1758), in the central and eastern parts of the Balkans: A multivariate study

2003 ◽  
Vol 24 (3) ◽  
pp. 359-377 ◽  
Author(s):  
Georg Džukić ◽  
Ljiljana Tomović
Keyword(s):  
Multivariate Analyses ◽  
Morphological Differentiation ◽  
Balkan Peninsula ◽  
Morphological Characters ◽  
Geographic Variability ◽  
The Balkans ◽  
Multivariate Study ◽  
Yugoslav Republic ◽  
North Western ◽  
Vipera Ammodytes

AbstractA multivariate analyses of various morphological characters (morphometric, meristic and qualitative) of nose-horned viper (Vipera ammodytes) revealed a complex morphological differentiation of populations from the central and the eastern Balkan Peninsula. Analyses of quantitative data showed no clear morphological discrimination or well-defined taxonomical units. On the contrary, analyses of qualitative traits separated two discrete taxa in the analysed area. One, inhabiting the eastern and the southern part of the Balkans, includes samples from most parts of Bulgaria, Former Yugoslav Republic of Macedonia and south-eastern Serbia, whereas the other ranges from north-western Bulgaria through the main part of Serbia (except the south-east) to Montenegro.

scholarly journals Why lemmings have indoor plumbing in summer

1996 ◽  
Vol 74 (10) ◽  
pp. 1947-1949 ◽  
Author(s):  
Rudy Boonstra ◽  
Charles J. Krebs ◽  
Alice Kenney
Keyword(s):  
Predation Risk ◽  
Ultraviolet Light ◽  
Canadian Arctic ◽  
Falco Tinnunculus ◽  
Vegetation Growth ◽  
Hunting Activity ◽  
Microtine Rodents ◽  
Dicrostonyx Groenlandicus ◽  
High Predation ◽  
Buteo Lagopus

The faeces and urine of microtine rodents are visible in ultraviolet light, and diurnal raptors, such as European kestrels (Falco tinnunculus) and rough-legged buzzards (Buteo lagopus), have the ability to see in ultraviolet light. It has been reported that in Fennoscandia, these raptors use this ability to concentrate their hunting activity in spring on areas where microtines are abundant. We hypothesized that in arctic tundra areas in summer, intense avian predation pressure and short vegetation should select for microtine behaviour that would minimize their exposure to these raptors. We dug up 62 collared lemming (Dicrostonyx groenlandicus) burrows in the Canadian Arctic and all had underground latrines. Latrines are not hidden underground in winter, when lemmings live under the snow, build nests above ground, and defecate above ground, nor does this occur in microtine species living in temperate areas, where summer vegetation growth is greater. Thus, high predation risk may influence not only where prey forage but also where they defecate.

Sm–Nd fluorite dating of Proterozoic low-sulfidation epithermal Au–Ag deposits and U–Pb zircon dating of host rocks at Mallery Lake, Nunavut, Canada

2003 ◽  
Vol 40 (12) ◽  
pp. 1789-1804 ◽  
Author(s):  
William A Turner ◽  
Larry M Heaman ◽  
Robert A Creaser
Keyword(s):  
Linear Trend ◽  
Lake Basin ◽  
Age Difference ◽  
Lake Area ◽  
Epithermal Deposits ◽  
Intimate Association ◽  
Baker Lake ◽  
End Members ◽  
Host Rocks ◽  
Low Sulfidation

The Mallery Lake area contains precious metal-bearing quartz–chalcedony stockworks that are pristine examples of ancient low-sulfidation epithermal deposits. Fluorite extracted from these epithermal deposits define a Sm–Nd errorchron age of 1434 ± 23 Ma mean square of weighted deviates (MSWD) = 4.8. This date is interpreted to have age significance because (1) a simple linear trend does not exist between the 143Nd/144Nd ratios of the fluorite with respect to their 1/Nd concentrations as would be expected for mixing of two geochemical end members; (2) microthermometric studies indicate that the fluorite analysed in this study has an intimate association with a single high-salinity, calcic brinal fluid; and (3) the age determined from seven fluorite samples extracted from a single outcrop location yielded an identical age result (1434 ± 60 Ma; MSWD = 5.5) compared to the fluorite composite. Rhyodacites of the Pitz Formation and syenites from the Nueltin suite (intrusive equivalent to the rhyodacites) are the youngest volcanic–plutonic rocks that are observed in outcrop in the Mallery Lake area, and they were dated by U–Pb zircon analysis at 1760 ± 43 Ma and 1755.4 ± 1.8 Ma, respectively. The ~320 million year age difference between the epithermal deposits and the hosting rhyodacitic flows suggests that the epithermal stockworks may have formed by a regional hydrothermal event unrelated to this earlier Paleoproterozoic volcanic activity. Uranium deposits in the Thelon and Athabasca basins, to the northwest and south of the Baker Lake Basin, were determined to have similar ore emplacement ages with no evident heat source.

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