Natural intersectional hybridization between North American species of Populus (Salicaceae) in sections Aigeiros and Tacamahaca. III. Paleobotany and evolution

1984 ◽  
Vol 62 (2) ◽  
pp. 336-342 ◽  
Author(s):  
James E. Eckenwalder
Keyword(s):  
Gene Flow ◽  
North America ◽  
North American Species ◽  
Sister Species ◽  
Western North America ◽  
Apparent Absence ◽  
Hybrid Species ◽  
Present Evidence ◽  
Evolutionary Role

Fossilized leaves resembling those of contemporary intersectional hybrids occur together with leaves assignable to sections Tacamahaca Spach and Aigeiros Duby in Miocene and Pliocene sediments in western North America. They are not referable to any particular extant hybrid species and are assigned to the extinct Populus × parcedentata Axelrod. Together with other evidence, these ancient hybrids raise questions concerning the evolutionary role of hybridization between species of the two parent sections. Present evidence about hybridization as a bridge for intersectional gene flow is contradictory. The apparent absence of backcrossed individuals in most studied hybridizing populations is offset by morphological pecularitics shared by sympatric cottonwoods and balsam poplars that are not shared with their cladistic sister species.

A new North American species of Simulium (Hellichiella) (Diptera: Simuliidae)

1991 ◽  
Vol 69 (11) ◽  
pp. 2867-2872 ◽  
Author(s):  
Peter H. Adler ◽  
D. M. Wood
Keyword(s):  
New Species ◽  
North America ◽  
North American ◽  
Polytene Chromosomes ◽  
North American Species ◽  
Sister Species ◽  
Life Stages ◽  
Western North America ◽  
A New Species

All life stages and the polytene chromosomes of Simulium (Hellichiella)curriei, a new species from western North America, are described and illustrated. This species is the only Nearctic member of the subgenus with an eight-filamented pupal gill. It is the sister-species of S. rivuli.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

A New Gunnel, Pholis clemensi, from the Coast of Western North America

1964 ◽  
Vol 21 (5) ◽  
pp. 933-939 ◽  
Author(s):  
Richard H. Rosenblatt
Keyword(s):  
British Columbia ◽  
New Species ◽  
North America ◽  
North American ◽  
North American Species ◽  
Western North America ◽  
The North ◽  
The Family ◽  
Juan De Fuca ◽  
A New Species

A new species, Pholis clemensi, referred to the family Pholidae, is named and described from 12 specimens taken in southern British Columbia waters and the Strait of Juan de Fuca. Pholis clemensi is compared with other members of the genus, and a key is given to the North American species.

scholarly journals The Role of Basketry in Early Holocene Small Seed Exploitation: Implications of a Ca. 9,000 Year-Old Basket from Cowboy Cave, Utah

2008 ◽  
Vol 73 (1) ◽  
pp. 83-102 ◽  
Author(s):  
Phil R. Geib ◽  
Edward A. Jolie
Keyword(s):  
North America ◽  
Great Basin ◽  
Processing Technique ◽  
Early Holocene ◽  
Western North America ◽  
Seed Processing ◽  
Small Seed ◽  
Food Exploitation ◽  
The Continuum

Despite ranking at the low end of the continuum in net caloric benefit relative to other foods, small seeds assumed great dietary importance in many parts of the world, including western North America. In a series of publications, Adovasio (1970a, 1974, 1980, 1986) argued that coiled basketry technology was invented in the eastern Great Basin during the early Holocene as a specialized food-processing technique. Coiled baskets are indeed useful for collecting and processing seeds, but it does not necessarily follow that they were originally designed for this purpose. A whole basket recently discovered at Cowboy Cave in southeastern Utah returned an AMS radiocarbon assay of 7960 ± 50 B.P., making it currently the earliest directly dated coiled basket from the Americas. This basket is not a parching tray and likely had nothing to do with harvesting seeds. We discuss the implications of this find with regard to tracking the temporal spread of coiled basketry technology in western North America and the role of coiled and twined forms in the initiation of small seed exploitation. Coiled and twined baskets for small seed processing may result from reconfiguration of existing technologies to create novel forms suited to a new food exploitation strategy.

Canada lynx gene flow across a mountain transition zone in western North America

2020 ◽  
Author(s):  
Cristen M Watt ◽  
Elizabeth M Kierepka ◽  
Catarina C. Ferreira ◽  
Erin L Koen ◽  
Jeffrey R. Row ◽  
...  
Keyword(s):  
Gene Flow ◽  
North America ◽  
Rocky Mountains ◽  
Forest Cover ◽  
Geographic Distance ◽  
Lynx Lynx ◽  
Western North America ◽  
Ecological Divergence ◽  
Canada Lynx ◽  
Barrier Effects

Mountain ecotones have the potential to cause multiple patterns in divergence, from simple barrier effects to more fundamental ecological divergence. Most work in mountain ecotones in North America has focused on reinforcement between refugial populations, making prediction of how mountains impact species that are not restricted to separate glacial refugia remains difficult. This study focused on the Canada lynx (Lynx canadensis Kerr, 1792), a highly mobile felid considered to be a habitat and dietary specialist. Specifically, we used 14 microsatellite loci and landscape genetic tools to investigate if the Rocky Mountains and associated climatic transitions influence lynx genetic differentiation in western North America. Although lynx exhibited high gene flow across the region, analyses detected structuring of neutral genetic variation across our study area. Gene flow for lynx most strongly related to temperature and elevation compared to other landscape variables (terrain roughness, percent forest cover, and habitat suitability index) and geographic distance alone. Overall, genetic structure in lynx is most consistent with barrier effects created by the Rocky Mountains rather than ecological divergence. Furthermore, warmer temperatures had a measurable impact on gene flow, which suggests connectivity may further decrease in peripheral or fragmented populations as climate warms.

scholarly journals A new species of Cybaeus L. Koch, 1868 (Araneae, Cybaeidae) with simple genitalia from central Japan is the sister species of C. melanoparvus Kobayashi, 2006 with elongated genitalia

2021 ◽  
Vol 97 (1) ◽  
pp. 223-233
Author(s):  
Yusuke Sugawara ◽  
Yoh Ihara ◽  
Takafumi Nakano
Keyword(s):  
New Species ◽  
North America ◽  
Lateral Surface ◽  
Phylogenetic Analyses ◽  
Mitochondrial Gene ◽  
Sister Species ◽  
Western North America ◽  
Central Japan ◽  
Gene Markers ◽  
A New Species

Spiders of the genus Cybaeus L. Koch, 1868 exhibit two major centers of diversity: Western North America and Japan. Several Japanese Cybaeus possess an elongated embolus in the male palp and elongated tubular spermathecae in the female genitalia. Here we describe Cybaeus koikeisp. nov. from central Honshu, Japan, which has an unelongated embolus and bulbous spermathecae. Phylogenetic analyses using nuclear and mitochondrial gene markers clearly support the monophyly of C. koikeisp. nov. and Cybaeus melanoparvus Kobayashi, 2006, a species with elongated genitalia. Both species share a similar habitus and a cluster of robust setae on the lateral surface of the male palpal patella. The latter is considered a synapomorphy for C. koikeisp. nov. and C. melanoparvus. A supplementary description of the spermathecae of C. melanoparvus is also provided.

scholarly journals Barrier to Gene Flow Between Eastern and Western Populations of Cronartium ribicola in North America

2000 ◽  
Vol 90 (10) ◽  
pp. 1073-1078 ◽  
Author(s):  
R. C. Hamelin ◽  
R. S. Hunt ◽  
B. W. Geils ◽  
G. D. Jensen ◽  
V. Jacobi ◽  
...  
Keyword(s):  
Gene Flow ◽  
New Mexico ◽  
North America ◽  
Random Amplified Polymorphic Dna ◽  
Principal Component ◽  
Genetic Distances ◽  
Group Method ◽  
Cronartium Ribicola ◽  
Western North America ◽  
Pair Group

The population structure of Cronartium ribicola from eastern and western North America was studied to test the null hypothesis that populations are panmictic across the continent. Random amplified polymorphic DNA markers previously characterized in eastern populations were mostly fixed in western populations, yielding high levels of genetic differentiation between eastern and western populations (φst = 0.55; θ = 0.36; P < 0.001). An unweighted pair-group method, arithmetic mean dendro-gram based on genetic distances separated the four eastern and four western populations into two distinct clusters along geographic lines. Similarly, a principal component analysis using marker frequency yielded one cluster of eastern populations and a second cluster of western populations. The population from New Mexico was clearly within the western cluster in both analyses, confirming the western origin of this recent introduction. This population was completely fixed (Hj = 0.000; n = 45) at all loci suggesting a severe recent population bottleneck. Genetic distances were low among populations of western North America (0.00 to 0.02) and among eastern populations (0.00 to 0.02), indicating a very similar genetic composition. In contrast, genetic distances between eastern and western populations were large, and all were significantly different from 0 (0.07 to 0.19; P < 0.001). Indirect estimates of migration were high among western populations, including the number of migrants among pairs of populations (Nm > 1) between New Mexico and British Columbia populations, but were smaller than one migrant per generation between eastern and western populations. These results suggest the presence of a barrier to gene flow between C. ribicola populations from eastern and western North America.

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