scholarly journals Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America

2016 ◽  
Vol 12 (4) ◽  
pp. 20160062 ◽  
Author(s):  
Kieren J. Mitchell ◽  
Sarah C. Bray ◽  
Pere Bover ◽  
Leopoldo Soibelzon ◽  
Blaine W. Schubert ◽  
...  
Keyword(s):  
South America ◽  
North American ◽  
Convergent Evolution ◽  
Phylogenetic Analyses ◽  
Early Pleistocene ◽  
South American ◽  
The North ◽  
Molecular Phylogenetic ◽  
North And South America ◽  
North And South

The Tremarctinae are a subfamily of bears endemic to the New World, including two of the largest terrestrial mammalian carnivores that have ever lived: the giant, short-faced bears Arctodus simus from North America and Arctotherium angustidens from South America (greater than or equal to 1000 kg). Arctotherium angustidens became extinct during the Early Pleistocene, whereas Arctodus simus went extinct at the very end of the Pleistocene. The only living tremarctine is the spectacled bear ( Tremarctos ornatus ), a largely herbivorous bear that is today only found in South America. The relationships among the spectacled bears ( Tremarctos ), South American short-faced bears ( Arctotherium ) and North American short-faced bears ( Arctodus ) remain uncertain. In this study, we sequenced a mitochondrial genome from an Arctotherium femur preserved in a Chilean cave. Our molecular phylogenetic analyses revealed that the South American short-faced bears were more closely related to the extant South American spectacled bear than to the North American short-faced bears. This result suggests striking convergent evolution of giant forms in the two groups of short-faced bears ( Arctodus and Arctotherium ), potentially as an adaptation to dominate competition for megafaunal carcasses.

scholarly journals A Single Chromosome Unexpectedly Links Highly Divergent Isolates of Toxoplasma gondii

mBio ◽  
2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Katelyn A. Walzer ◽  
Jon P. Boyle
Keyword(s):  
Toxoplasma Gondii ◽  
South America ◽  
North American ◽  
Phylogenetic Analyses ◽  
Unexpected Finding ◽  
Type I ◽  
South American ◽  
Single Chromosome ◽  
Content Type ◽  
The North

ABSTRACT Toxoplasma gondii is an obligate intracellular parasite that can cause disease in all warm-blooded animals studied to date, including humans. Over a billion people have been infected with this parasite worldwide. In Europe and North America, Toxoplasma has a clonal population structure, where only three lineages are highly dominant (strain types I, II, and III). Khan et al. [mBio 2(6): e00228-11, 2011] have carried out phylogenetic analyses on a large number of diverse strains from outside of these lineages and found evidence for a significant split between the clonal North American/European lineages and those in South America. In contrast to most of the genome, nearly all North American/European strains sampled, and the majority of South American strains sampled, harbored at least portions of a monomorphic chromosome Ia (Ia*). In contrast to previous models, these data suggest that the monomorphic haplotype originated in South America and migrated to the North. These authors propose that South American haplotype 12 was a precursor to modern-day type II, while South American haplotypes 6 and 9 crossed with haplotype 12 to give rise to the type I and III lineages, respectively. However, the findings reported by Khan et al. complicate the origin of chromosome Ia, since there are members of haplotypes 9 and 12 with nearly complete versions of Ia* and members of haplotypes 6 and 12 with over 50% of Ia*. This unexpected finding raises exciting new questions about how an entire common chromosome can be found within strains that are highly divergent at most other genomic loci.

scholarly journals Disproportionate extinction of South American mammals drove the asymmetry of the Great American Biotic Interchange

2020 ◽  
Vol 117 (42) ◽  
pp. 26281-26287 ◽  
Author(s):  
Juan D. Carrillo ◽  
Søren Faurby ◽  
Daniele Silvestro ◽  
Alexander Zizka ◽  
Carlos Jaramillo ◽  
...  
Keyword(s):  
South America ◽  
North American ◽  
Biotic Interactions ◽  
South American ◽  
Dispersal Rate ◽  
Great American Biotic Interchange ◽  
Drastic Increase ◽  
The Asymmetry ◽  
North And South America ◽  
North And South

The interchange between the previously disconnected faunas of North and South America was a massive experiment in biological invasion. A major gap in our understanding of this invasion is why there was a drastic increase in the proportion of mammals of North American origin found in South America. Four nonmutually exclusive mechanisms may explain this asymmetry: 1) Higher dispersal rate of North American mammals toward the south, 2) higher origination of North American immigrants in South America, 3) higher extinction of mammals with South American origin, and 4) similar dispersal rate but a larger pool of native taxa in North versus South America. We test among these mechanisms by analyzing ∼20,000 fossil occurrences with Bayesian methods to infer dispersal and diversification rates and taxonomic selectivity of immigrants. We find no differences in the dispersal and origination rates of immigrants. In contrast, native South American mammals show higher extinction. We also find that two clades with North American origin (Carnivora and Artiodactyla) had significantly more immigrants in South America than other clades. Altogether, the asymmetry of the interchange was not due to higher origination of immigrants in South America as previously suggested, but resulted from higher extinction of native taxa in southern South America. These results from one of the greatest biological invasions highlight how biogeographic processes and biotic interactions can shape continental diversity.

Diversification of the North American Doellingeria-Eucephalus Clade (Astereae: Asteraceae) Inferred from Molecular and Morphological Evidence

2019 ◽  
Vol 44 (4) ◽  
pp. 930-942
Author(s):  
Geraldine A. Allen ◽  
Luc Brouillet ◽  
John C. Semple ◽  
Heidi J. Guest ◽  
Robert Underhill
Keyword(s):  
North American ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Sister Group ◽  
Morphological Evidence ◽  
South American ◽  
New Combinations ◽  
The North ◽  
Hybridization Event ◽  
Ancient Hybridization

Abstract—Doellingeria and Eucephalus form the earliest-diverging clade of the North American Astereae lineage. Phylogenetic analyses of both nuclear and plastid sequence data show that the Doellingeria-Eucephalus clade consists of two main subclades that differ from current circumscriptions of the two genera. Doellingeria is the sister group to E. elegans, and the Doellingeria + E. elegans subclade in turn is sister to the subclade containing all remaining species of Eucephalus. In the plastid phylogeny, the two subclades are deeply divergent, a pattern that is consistent with an ancient hybridization event involving ancestral species of the Doellingeria-Eucephalus clade and an ancestral taxon of a related North American or South American group. Divergence of the two Doellingeria-Eucephalus subclades may have occurred in association with northward migration from South American ancestors. We combine these two genera under the older of the two names, Doellingeria, and propose 12 new combinations (10 species and two varieties) for all species of Eucephalus.

A revision of the Leptogium saturninum group in North America

2016 ◽  
Vol 48 (5) ◽  
pp. 387-421 ◽  
Author(s):  
Daphne F. STONE ◽  
James W. HINDS ◽  
Frances L. ANDERSON ◽  
James C. LENDEMER
Keyword(s):  
North American ◽  
Morphological Study ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Lower Surface ◽  
Molecular Data ◽  
The North ◽  
Molecular Phylogenetic ◽  
Nrits Sequence

AbstractA revision of the North American members of the Leptogium saturninum group (i.e. species with long lower-surface hairs, isidia, and usually smooth upper surface) is presented based on molecular phylogenetic analyses of mtSSU and nrITS sequence data, together with an extensive morphological study. Three species supported by both molecular and morphological characteristics are recognized: L. acadiense sp. nov. (distinguished by granular saturninum-type isidia, medulla composed of irregularly arranged or perpendicular hyphae), L. cookii sp. nov. (distinguished by cylindrical saturninum-type isidia) and L. hirsutum (distinguished by hirsutum-type isidia and medulla composed of loosely intertwined hyphae). One species supported by morphological characteristics, but for which no molecular data could be generated, is also recognized: L. compactum sp. nov. (distinguished by hirsutum-type isidia and medulla composed of tightly packed hyphae). Finally, L. saturninum (distinguished by granular saturninum-type isidia and medulla composed of perpendicular and parallel hyphae) is supported by morphological characteristics but molecular data from geographically diverse populations, including those near the type locality, indicate that the morphologically defined species is paraphyletic. Leptogium burnetiae is excluded from North American based on morphological study of the type. The species are described and illustrated in detail, and are distinguished morphologically by their isidium development, morphology of mature isidia, and pattern of hyphae in the medulla in transverse sections near lobe margins. A key to the members of the L. saturninum group and related species is also presented.

scholarly journals Soybean Sudden Death Syndrome Species Diversity Within North and South America Revealed by Multilocus Genotyping

2010 ◽  
Vol 100 (1) ◽  
pp. 58-71 ◽  
Author(s):  
Kerry O'Donnell ◽  
Stacy Sink ◽  
María Mercedes Scandiani ◽  
Alicia Luque ◽  
Analía Colletto ◽  
...  
Keyword(s):  
Sudden Death ◽  
South America ◽  
Sudden Death Syndrome ◽  
Molecular Diagnostic ◽  
Sequence Analyses ◽  
Diagnostic Assays ◽  
Molecular Phylogenetic ◽  
Species Specific ◽  
North And South America ◽  
North And South

Sudden death syndrome (SDS) of soybean has become a serious constraint to the production of this crop in North and South America. Phenotypic and multilocus molecular phylogenetic analyses, as well as pathogenicity experiments, have demonstrated that four morphologically and phylogenetically distinct fusaria can induce soybean SDS. Published molecular diagnostic assays for the detection and identification of these pathogens have reported these pathogens as F. solani, F. solani f. sp. glycines, or F. solani f. sp. phaseoli, primarily because the species limits of these four pathogens were only recently resolved. In light of the recent discovery that soybean SDS and Phaseolus and mung bean root rot (BRR) are caused by four and two distinct species, respectively, multilocus DNA sequence analyses were conducted to assess whether any of the published molecular diagnostic assays were species-specific. Comparative DNA sequence analyses of the soybean SDS and BRR pathogens revealed that highly conserved regions of three loci were used in the design of these assays, and therefore none were species-specific based on our current understanding of species limits within the SDS–BRR clade. Prompted by this finding, we developed a high-throughput multilocus genotyping (MLGT) assay which accurately differentiated the soybean SDS and two closely related Phaseolus and mung BRR pathogens based on nucleotide polymorphism within the nuclear ribosomal intergenic spacer region rDNA and two anonymous intergenic regions designated locus 51 and 96. The single-well diagnostic assay, employing flow cytometry and a novel fluorescent microsphere array, was validated by independent multilocus molecular phylogenetic analysis of a 65 isolate design panel. The MLGT assay was used to reproducibly type a total of 262 soybean SDS and 9 BRR pathogens. The validated MLGT array provides a unique molecular diagnostic for the accurate identification and molecular surveillance of these economically important plant pathogens.

Redescription and new records of Ontholestes brasilianus Bernhauer, 1906 (Coleoptera: Staphylinidae: Staphylininae) 

Zootaxa ◽  
2018 ◽  
Vol 4388 (1) ◽  
pp. 143
Author(s):  
VINÍCIUS COSTA-SILVA ◽  
ANGÉLICO ASENJO ◽  
ALFRED F. NEWTON ◽  
PATRICIA J. THYSSEN
Keyword(s):  
South America ◽  
New Records ◽  
South American ◽  
South American Species ◽  
Additional Species ◽  
Palearctic Species ◽  
Mistaken Identification ◽  
North And South America ◽  
First Time ◽  
North And South

The genus Ontholestes Ganglbauer includes 35 species distributed mainly in Eurasia, with a few additional species in Africa and North and South America (Herman, 2001; Yang & Zhou, 2012; Smetana & Shavrin, 2013; Rougemont, 2016). According to Asenjo et al. (2013), the South American record of the Palearctic species Ontholestes murinus (Linnaeus, 1758) for Brazil made by J. Guérin (1953) seems doubtful. Ontholestes murinus was recorded for the first time outside the Palaearctic region by Smetana (1981), from Newfoundland, in Canada, as an adventive species (e.g., Downie and Arnett, 1996; Brunke et al., 2011), but its occurrence in Brazil remains to be confirmed; if the Guérin (1953) record was based on a mistaken identification or mislabeled specimen, this would reduce the number of species distributed in this region from two to one. With respect to O. brasilianus Bernhauer, although it has been confirmed for Peru, Brazil and Argentina (Herman, 2001; Asenjo et al., 2013; Newton, 2015; Newton & Caron, 2015), no specific localities of occurrence have been reported since its description in 1906. Thus, to solve problems of misidentification with Neotropical species of this genus, in this study we redescribe Ontholestes brasilianus and provide the first illustrations of the beetle including its aedeagus and a short key for South American species. Additionally, new records from South America are listed here. 

The Kinetic Empires of Native American Nomads

2021 ◽  
pp. 1035-1057
Author(s):  
Pekka Hämäläinen
Keyword(s):  
Native American ◽  
South America ◽  
Great Plains ◽  
South American ◽  
Collective Identities ◽  
Long Distance ◽  
The North ◽  
Political Unity ◽  
And Control ◽  
North And South

This chapter re-examines the powerful nomadic-equestrian societies in the North and South American grasslands and makes the case for a distinctive imperial formation, the kinetic empire. Kinetic empires were shape-shifting, action-based regimes that turned mobility into an imperial strategy and revolved around mobile activities: long-distance raiding, seasonal expansions, transnational diplomatic missions, semi-permanent trade fairs, recurring political assemblies, and control over shifting nodes. Their governing systems were light and flexible, and they rose and stayed in power by capitalizing on their superior capacity to access and connect political and economic centers around them. The Comanche and Lakota Indians created the Western Hemisphere’s most prominent examples of kinetic empires in the North American Great Plains. In South America the Araucanians frustrated European colonizing efforts, commanded a large and expanding territory, and pulled other Native groups on their orbit, but lacked the Comanches’ and Lakotas’ strong collective identities and political unity.

RAPD analysis of the relationship of North and South American subspecies of Fragaria chiloensis

1998 ◽  
Vol 76 (10) ◽  
pp. 1812-1817 ◽  
Author(s):  
Sue Porebski ◽  
Paul M Catling
Keyword(s):  
North American ◽  
Random Amplified Polymorphic Dna ◽  
Molecular Evidence ◽  
South American ◽  
Cophenetic Correlation ◽  
The North ◽  
Fragaria Chiloensis ◽  
Protection And Utilization ◽  
Relationship Of ◽  
North And South

To improve the intraspecific classification of Fragaria chiloensis (L.) Duchesne, 35 plants including 5 North American ssp. lucida, 15 North American ssp. pacifica, and 15 South American ssp. chiloensis were analysed using random amplified polymorphic DNA (RAPDs). From 100 primers screened, 12 were selected providing 62 scorable polymorphic bands. The phenogram (cophenetic correlation, r = 0.99) based on UPGMA clustering of Jaccard's coefficients revealed a clear division between North American and South American plants, but only partial separation was shown between the two North American subspecies. This is the first comprehensive molecular evidence for major genetic divergence between the North American and South American subspecies of F. chiloensis and suggests greater genetic variation within the Canadian material of the North American ssp. pacifica than within the South American ssp.chiloensis. These findings strongly support protection and utilization of wild Canadian Fragaria germplasm for crop improvement.Key words: strawberry, Fragaria chiloensis, ssp. chiloensis, ssp. pacifica, ssp. lucida, RAPD, variation, germplasm, Canada, United States, Chile.

Jujuyaspis borealis and associated trilobites and conodonts from the Lower Ordovician of Texas and Utah

1987 ◽  
Vol 61 (1) ◽  
pp. 112-121 ◽  
Author(s):  
James H. Stitt ◽  
James F. Miller
Keyword(s):  
United States ◽  
South America ◽  
North American ◽  
The United States ◽  
International Agreement ◽  
Lower Ordovician ◽  
Central Texas ◽  
North And South America ◽  
First Time ◽  
North And South

Jujuyaspis borealis is reported from earliest Ordovician (North American usage) limestones in central Texas and western Utah, the first time this species has been recognized in the United States. Jujuyaspis is a widespread olenid trilobite that occurs near the base of the Tremadoc Series in a variety of lithologies in North and South America, Europe, and Asia. When international agreement is reached on the exact horizon at or near the base of the Tremadoc Series that is to be used as the Cambrian–Ordovician boundary, Jujuyaspis will likely prove to be a very useful taxon for recognition of the boundary interval.

scholarly journals An Unusual New Genus of Chrysididae From Oman (Hymenoptera)

1987 ◽  
Vol 94 (3-4) ◽  
pp. 333-335
Author(s):  
Lynn Siri Kimsey
Keyword(s):  
North America ◽  
Middle East ◽  
South America ◽  
North Africa ◽  
North American ◽  
New Genus ◽  
Diverse Group ◽  
North And South America ◽  
North And South

The chrysidid tribe Elampini comprises a diverse group of genera. There are a number of small (1-3 species) highly derived genera in this group. Nearly all of these occur in 2 regions, southwestern North America and the area comprising the Middle East, southern USSR and North Africa. The small North American genera are Hedychreides Bohart, Microchridium Bohart, Minymischa Kimsey, Pseudolopyga Bodenstein and Xerochrum Bobart. Those in the latter region include: Haba Semenov, Prochridium Linsenmaier and the new genus, Adelopyga, described below. One genus, Muesebeckidium Krombein, occurs in both North and South America.The following abbreviations are used: F = flagellomere, MOD = midocellus diameter, PD = puncture diameter, Rs = forewing radial sector, and S = gastral sternum.

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