Patterns of geographic variation in the skull of Nearctic Ermine (Mustela erminea)

1990 ◽  
Vol 68 (6) ◽  
pp. 1241-1249 ◽  
Author(s):  
Judith L. Eger
Keyword(s):  
Geographic Variation ◽  
North American ◽  
Geographic Distance ◽  
Glacial Refugia ◽  
Clinal Variation ◽  
Shape Variation ◽  
Mustela Erminea ◽  
Temperature And Precipitation ◽  
Glacial Stage ◽  
Species Groups

A. H. Macpherson suggested that much of the current geographic diversity in species and species groups of arctic mammals resulted from isolation in glacial refugia during the Wisconsin glacial stage. The present study evaluates this refugium hypothesis using a statistical assessment of geographic variation in 13 craniometric characters of Nearctic Mustela erminea. There is significant geographic variation among samples of North American ermine. Most of the skull character variance in this species reflects differences in size and is clinal. Variation in skull size is better explained by temperature and precipitation variables than by geographic distance, suggesting that environmentally ordered selection for size has been superimposed on any size differentiation that occurred during isolation in refugia. Variation in skull shape shows a relatively low correlation with climatic variables, and partitioning tests on shape variation reveal discontinuities consistent with the refugium hypothesis. Distinctive groups of samples reflect possible refugial populations in Eastern Beringia, in periglacial refugia south of the Wisconsin ice in eastern North America, and in one or more western North American refugia.

Geographic Variation in North American Ninespine Sticklebacks, Pungitius pungitius

1963 ◽  
Vol 20 (1) ◽  
pp. 27-44 ◽  
Author(s):  
J. D. McPhail
Keyword(s):  
Geographic Variation ◽  
North American ◽  
Glacial Refugia ◽  
The Arctic ◽  
Pungitius Pungitius ◽  
Gill Rakers ◽  
Spine Length ◽  
Present Distribution ◽  
Tidal Waters ◽  
Lateral Plates

Ventral spine length and the number of lateral plates, dorsal spines, and gill rakers in Pungitius pungitius from 132 North American localities were compared. The number of lateral plates is consistently high in populations from tidal waters, and low in inland populations. Geographic variation in the number of dorsal spines and gill rakers suggest two allopatric forms of P. pungitius in North America. A Bering form ranges from Alaska along the arctic coasts of Canada, and a Mississippi form ranges from the Great Lakes to the Mackenzie River. Two glacial refugia are hypothesised to explain the origin and present distribution of these forms.

THE GENUS EUXOA (LEPIDOPTERA: NOCTUIDAE) IN NORTH AMERICA: I. SUBGENERA OROSAGROTIS, LONGIVESICA, CHORIZAGROTIS, PLEONECTOPODA, AND CRASSIVESICA

1970 ◽  
Vol 102 (S67) ◽  
pp. 7-177 ◽  
Author(s):  
David F. Hardwick
Keyword(s):  
New Species ◽  
North America ◽  
Geographic Variation ◽  
North American ◽  
Male Genitalia ◽  
North American Species ◽  
Species Groups ◽  
Lepidoptera Noctuidae ◽  
Adequate Analysis

AbstractThe large and complex genus Euxoa is divided into six subgenera: Orosagrotis, Longivesica, Euxoa, Chorizagrotis, Pleonectopoda, and Crassivesica. Orosagrotis and Chorizagrotis have until now been considered as valid noctuid genera by many workers. Longivesica and Crassivesica are here described as new. The taxonomy and distribution of North American species in all subgenera except the very extensive subgenus Euxoa are considered in the present paper. Only 49 species in a probable North American Euxoa fauna of some 200 species are included in the five subgenera reviewed here, however.Within the genus, species have been segregated into subgenera and species groups largely on the basis of the structure of the male genitalia, and particularly on the conformation of the vesica of the male. Keys to subgenera, species groups, and species are presented. No new species are described. Subspecies are not formally considered because an adequate analysis of the often complex geographic variation is beyond the scope of this paper.

The fossil record and macroevolutionary history of North American ungulate mammals: standardizing variation in intensity and geography of sampling

Paleobiology ◽  
10.1666/13052 ◽  
2014 ◽  
Vol 40 (2) ◽  
pp. 238-255 ◽  
Author(s):  
Jonathan D. Marcot
Keyword(s):  
Convex Hull ◽  
Environmental Change ◽  
Geographic Variation ◽  
North American ◽  
Fossil Record ◽  
Geographic Distance ◽  
Geographic Location ◽  
Pairwise Distance ◽  
Evolutionary Response ◽  
Over Time

The record of the taxonomic evolution of North American ungulates is critical to our understanding of mammalian evolution and environmental change throughout the Cenozoic. The distribution of sampling in the ungulate fossil record over time and geographic space and the degree to which this biases the observed patterns of taxonomic evolution is poorly understood. To address these issues, I placed fossil collections and occurrences drawn from the Paleobiology Database into 2-Myr time intervals between 55 and 1 Ma. I determined the variation in numbers of fossil collections and occurrences, using three metrics to measure geographic variation: first, the area of the convex hull containing all collections in an interval, to determine the areal coverage of sampling; second, the mean pairwise geographic distance among collections as a measurement of the dispersion of collections within that area; and third, the interval-to-interval migration of the geographic centroid of all collections, to calculate changes in the geographic location of sampling. Each of these showed considerable variation over the Cenozoic, and both the area of the convex hull (ACH) encompassing all collections in an interval, and mean pairwise distance (MPWD) among them showed increasing trends over time.To minimize the effect of variation in numbers of fossil samples over time, I used standard sample-standardization procedures. To minimize the effect of geographic variation in sampling over time, I standardized the area of sampling among intervals. I also employed both standardizations sequentially. Each standardization procedure had surprisingly little effect on observed patterns of taxonomic richness and rates. This indicates that, for North American ungulates, neither variation in number nor geographic distribution of fossil samples exerts an overwhelming influence on perceived macroevolutionary patterns. These results confirm the ungulate fossil record as a critical and faithful record for our understanding of Cenozoic environmental change and the mammalian evolutionary response.

Mollusc successions reveal northward postglacial shifts of Alpine species ranges (Bohemian Massif, Czech Republic)

The Holocene ◽  
2021 ◽  
pp. 095968362110116
Author(s):  
Lucie Juřičková ◽  
Jakub Menšík ◽  
Jitka Horáčková ◽  
Vojen Ložek
Keyword(s):  
Czech Republic ◽  
Bohemian Massif ◽  
Late Glacial ◽  
Glacial Refugia ◽  
Land Snails ◽  
Glacial Refugium ◽  
Local Climate ◽  
The Alps ◽  
Species Groups ◽  
Late Glacial And Holocene

The Alps are an important hotspot of species diversity and endemism, as well as a presumed glacial refugium of several species’ groups including land snails. The recent ranges of Alpine endemics are well known, but their fluctuations during the postglacial period mirroring local climate changes are understudied. By analysing five Late Glacial and Holocene mollusc successions from two areas in the southernmost part of the Bohemian Massif (Czech Republic) situated about 100 km north of the Alps, we reveal details of these fluctuations. The Alpine endemic rocky dweller Chilostoma achates had reached the southern part of the Bohemian Massif already in the Late Glacial and disappeared in the Mid-Holocene canopy forest optimum. On the contrary, the northern boundaries of Alpine canopy forest epigeic snails extended further north than today at the turn of the Middle and Late-Holocene, pointing to a more favourable forest microclimate. The earliest known occurrences of several temperate canopy forest central European species, especially Causa holosericea and Discus perspectivus, imply the role of different areas in the Alps as their glacial refugia.

Cybaeus (Araneae: Cybaeidae) in the Nearctic: the devius and tardatus species groups of the Californian clade

Zootaxa ◽  
2021 ◽  
Vol 5026 (4) ◽  
pp. 451-479
Author(s):  
ROBB BENNETT ◽  
CLAUDIA COPLEY ◽  
DARREN COPLEY
Keyword(s):  
Sierra Nevada ◽  
North American ◽  
Southern Coast ◽  
Distribution Maps ◽  
Identification Keys ◽  
Sierra Nevada Mountains ◽  
Moist Forest ◽  
Species Groups

Species of North American Cybaeus L. Koch (Araneae: RTA clade: Cybaeidae) are moist-forest spiders classified in Holarctic and Californian clades. Here, in the fourth paper in a planned series reviewing the six Californian clade species groups, we review the species of the devius and tardatus groups. We recognize five species in the devius group (Cybaeus bilectus Bennett spec. nov., C. bryoncavus Bennett spec. nov., C. devius Chamberlin & Ivie, C. echo Bennett spec. nov., and C. wilsonia Bennett spec. nov.) and four in the tardatus group (C. orarius Bennett spec. nov., C. piazzai Bennett spec. nov., C. tardatus Chamberlin, and C. topanga Bennett spec. nov.). All of these species are rarely encountered and have restricted distributions either in the central and southern Sierra Nevada Mountains of eastern California, U.S.A (devius group) or the southern coast of western California (tardatus group). Some of these species are likely endangered or already extinct; most have not been seen in many decades and none have been collected more recently than 1995. Descriptions, illustrations, distribution maps, and identification keys are provided as well as a discussion of conservation issues of relevance to the group.  

scholarly journals Permian phytogeography and climate

1992 ◽  
Vol 6 ◽  
pp. 329-329
Author(s):  
Alfred M. Ziegler ◽  
Eric D. Gyllenhaal
Keyword(s):  
General Circulation ◽  
General Scheme ◽  
Geographic Distance ◽  
Circulation Model ◽  
Taxonomic Diversity ◽  
Critical Groups ◽  
Multivariate Techniques ◽  
Generic Level ◽  
Temperature And Precipitation ◽  
Geographic Separation

A greater number of floral provinces have been defined for the Permian than for any other Phanerozoic period, and this is presumably the reflection of a well differentiated set of climate zones. These floras have been assigned to an idealized set of ten “biomes” as defined on the basis of the equator-to-pole spectrum of present day climates (Ziegler, 1990). The biomes reflect temperature and precipitation, and in particular the way in which these parameters change through the annual cycle. The purpose of the present paper is (1) to expand the taxonomic database of Permian floras and climatically sensitive sediments, (2) to use ordination analyses and other multivariate techniques to relate taxonomic data to climate, geographic distance and other factors that controlled the global distribution of plants, and (3) to relate these results to the recognition of biomes during the Permian.This approach reveals that the phytogeographic provinces, as recognized by paleobotanists, are objectively valid entities, but significant gradations can be detected, supporting the idea that the floras were controlled by climate rather than by geographic separation. In fact, there are no examples in the Permian world of strictly geographic barriers, which is not surprising in view of the fact that the continents were basically together through this time.Biomes are defined by climatic parameters, but the taxonomic characteristics of biomes have evolved with time. The Permian floral provinces can be related to precipitation balance by their associations with such climatically sensitive sediments as coals, paleosols and evaporites, and this is critical for assigning each to an appropriate biome. At least at the generic level, taxonomic lists have significant limitations for identification of biomes in the geologic past. In particular, northern and southern hemisphere temperate biomes evolved radically different floras by the Permian. Ecomorphic characters and taxonomic diversity within critical groups may provide a more general scheme for phytologic recognition of biomes through geologic time.Finally, detailed comparisons will be made to General Circulation Model and Energy Balance studies on the Permian. The numerical studies seem to overemphasize the seasonal extremes of temperature in the middle to high latitudes.

Individual signatures outweigh social group identity in contact calls of a communally nesting parrot

2019 ◽  
Vol 31 (2) ◽  
pp. 448-458 ◽  
Author(s):  
Grace Smith-Vidaurre ◽  
Marcelo Araya-Salas ◽  
Timothy F Wright
Keyword(s):  
Social Dynamics ◽  
Group Membership ◽  
Individual Recognition ◽  
Geographic Distance ◽  
Vocal Learning ◽  
Acoustic Similarity ◽  
Clinal Variation ◽  
Contact Call ◽  
Significant Similarity ◽  
Myiopsitta Monachus

Abstract Despite longstanding interest in the evolutionary origins and maintenance of vocal learning, we know relatively little about how social dynamics influence vocal learning processes in natural populations. The “signaling group membership” hypothesis proposes that socially learned calls evolved and are maintained as signals of group membership. However, in fission–fusion societies, individuals can interact in social groups across various social scales. For learned calls to signal group membership over multiple social scales, they must contain information about group membership over each of these scales, a concept termed “hierarchical mapping.” Monk parakeets (Myiopsitta monachus), small parrots native to South America, exhibit vocal mimicry in captivity and fission–fusion social dynamics in the wild. We examined patterns of contact call acoustic similarity in Uruguay to test the hierarchical mapping assumption of the signaling group membership hypothesis. We also asked whether geographic variation patterns matched regional dialects or geographic clines that have been documented in other vocal learning species. We used visual inspection, spectrographic cross-correlation and random forests, a machine learning approach, to evaluate contact call similarity. We compared acoustic similarity across social scales and geographic distance using Mantel tests and spatial autocorrelation. We found high similarity within individuals, and low, albeit significant, similarity within groups at the pair, flock and site social scales. Patterns of acoustic similarity over geographic distance did not match mosaic or graded patterns expected in dialectal or clinal variation. Our findings suggest that monk parakeet social interactions rely more heavily upon individual recognition than group membership at higher social scales.

Descriptions of four new species of the Ambrysus signoreti Stål species complex (Heteroptera: Nepomorpha: Naucoridae

Zootaxa ◽  
2019 ◽  
Vol 4615 (2) ◽  
pp. 285
Author(s):  
DANIEL REYNOSO-VELASCO ◽  
ROBERT W. SITES
Keyword(s):  
New Species ◽  
North American ◽  
Species Complex ◽  
The North ◽  
Species Groups ◽  
Multiple Species

The genus Ambrysus Stål is the most species rich genus of Naucoridae. Multiple species groups in the genus have been proposed, including the North American Ambrysus signoreti Stål complex. Four new species belonging to the A. signoreti complex are described and illustrated: three from Mexico (Ambrysus brailovskyi Reynoso & Sites n. sp., A. henryi Reynoso & Sites n. sp., A. schuhi Reynoso & Sites n. sp.) and one from Mexico and Guatemala (A. sitesi Reynoso n. sp.), bringing the total number of described species of Ambrysus to 97. 

scholarly journals Characterizing ENSO Coupled Variability and Its Impact on North American Seasonal Precipitation and Temperature*

2015 ◽  
Vol 28 (10) ◽  
pp. 4231-4245 ◽  
Author(s):  
Michelle L. L’Heureux ◽  
Michael K. Tippett ◽  
Anthony G. Barnston
Keyword(s):  
North American ◽  
Longwave Radiation ◽  
Climate Impacts ◽  
Spring Precipitation ◽  
Central Pacific ◽  
Complete Representation ◽  
Central Pacific Ocean ◽  
Temperature And Precipitation ◽  
Precipitation Anomalies ◽  
Coupled Variability

Abstract Two questions are addressed in this paper: whether ENSO can be adequately characterized by simple, seasonally invariant indices and whether the time series of a single component—SST or OLR—provides a sufficiently complete representation of ENSO for the purpose of quantifying U.S. climate impacts. Here, ENSO is defined as the leading mode of seasonally varying canonical correlation analysis (CCA) between anomalies of tropical Pacific SST and outgoing longwave radiation (OLR). The CCA reveals that the strongest regions of coupling are mostly invariant as a function of season and correspond to an OLR region located in the central Pacific Ocean (CP-OLR) and an SST region in the eastern Pacific that coincides with the Niño-3 region. In a linear context, the authors explore whether the use of a combined index of these SST and OLR regions explains additional variance of North American temperature and precipitation anomalies beyond that described by using a single index alone. Certain seasons and regions benefit from the use of a combined index. In particular, a combined index describes more variability in winter/spring precipitation and summer temperature.

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