A cytogenetic comparison of some North American owl species

Genome ◽  
1991 ◽  
Vol 34 (5) ◽  
pp. 714-717 ◽  
Author(s):  
Sheila M. Schmutz ◽  
Jane S. Moker
Keyword(s):  
North American ◽  
Karyotype Evolution ◽  
Considerable Similarity ◽  
Burrowing Owl ◽  
Separate Genus ◽  
Chromosomal Data ◽  
Common Genus

Karyotypes of three owl species previously not reported, the Burrowing Owl (Athene cunnicularia), the Hawk Owl (Surnia ulula), and the Western Screech Owl (Otus kennicotti), are presented. Comparison with other karyotypes in the literature suggests that the Burrowing Owl should be in a separate genus, as was previously the case. The Hawk Owl karyotype was found to bear considerable similarity to some Athene species, although we are not suggesting they should be placed in one genus. The karyotype of the Western Screech Owl appears to have diverged from the Otus species described previously, but these chromosomal data are not incompatible with these species sharing a common genus. A karyotype of the Long-eared Owl, which differs slightly from a previously published version, is presented. Relationships among the owls karyotyped to date are discussed on the basis of cladistic interpretations of these data.Key words: Strigiformes, phylogeny, karyotype, evolution, chromosome.

On the Morphology and Systematic Position of Echinopharynx, a New Genus of Bursate Nematode from Testudo tabulata

1925 ◽  
Vol 3 (1) ◽  
pp. 19-32
Author(s):  
Gobind Singh Thapar
Keyword(s):  
New Genus ◽  
Buccal Capsule ◽  
Systematic Position ◽  
Present Knowledge ◽  
Parasitic Fauna ◽  
Separate Genus ◽  
The Family ◽  
Common Genus ◽  
Anguis Fragilis ◽  
Improved Methods

Our present knowledge of the Strongylid parasites of reptiles is based primarily on Dujardin (1845), who refers all the forms along with those of other vertebrates under a common genus Strongylus, and described four species from the reptilian hosts. Since then our knowledge of parasitic fauna has considerably increased, and von Linstow (1878–89) gave an enlarged list under the same genus from reptiles and also a few under the genus Kalicephalus, Later, with improved methods of Nematode study the forms described were revised, and it was found necessary to split the genus Strongylus, and several groups of a diverse character were recognised. The genus Strongylus was thus split up into several genera, and some of them were removed from the family Strongylidæ. The form Strongylus dispar of Dujardin from the Anguis fragilis was removed into a separate genus, Oswaldocruzia and Strongylus auricularis, with its characters in the absence of buccal capsule and the bifid and trifid distal ends of the spicule seemed more closely allied to Trichostrongylidæ Leiper, and was also removed to the genus Oswaldocruzia.

scholarly journals Burrowing Owl (Athene Cunicularia) Population Genetics: A Comparison of North American Forms and Migratory Habits

The Auk ◽  
2005 ◽  
Vol 122 (2) ◽  
pp. 464-478 ◽  
Author(s):  
Nicole M. Korfanta ◽  
David B. McDonald ◽  
Travis C. Glenn
Keyword(s):  
Genetic Differentiation ◽  
North American ◽  
Habitat Structure ◽  
Gene Diversity ◽  
Athene Cunicularia ◽  
Population Declines ◽  
The West ◽  
Burrowing Owls ◽  
Burrowing Owl ◽  
Patchy Habitat

Abstract We assessed the effects of range disjunction, migratory habit, coloniality, and habitat structure on the genetic differentiation of North American Burrowing Owl (Athene cunicularia) populations. Burrowing Owls in North America comprise two forms or subspecies: A. c. floridana in Florida, separated by ∼1,500 km from the western form, A. c. hypugaea, which ranges from Texas to California and north to southern Canada. Burrowing Owls tend to be loosely colonial, and both the Florida populations and southerly populations of A. c. hypugaea from California to Texas are nonmigratory. To assess genetic structure, we examined 201 individuals from nine western and six Florida populations at seven highly variable microsatellite DNA loci. Mean gene diversity (Hexp) was higher in the west than in Florida (0.539 and 0.341, respectively; P < 0.05). Populations within subspecies were essentially panmictic (A. c. floridana: θ = 0.038, ρ = 0.014; A. c. hypugaea: θ = 0.014, ρ = 0.009) and even genetic differentiation across subspecies was modest (θ = 0.051, ρ = 0.014). Nevertheless, the western and Florida forms were easily distinguished by any of several criteria, such as allelic absences in Florida, assignment tests, and well-supported branches on the inferred phylogenetic tree. Genetic differentiation was at least twice as great in resident Florida (θ = 0.038) and California (θ = 0.021) populations as in migratory western populations (θ = 0.012), though 95% confidence intervals of theta estimates overlapped. We found no evidence of a genetic bottleneck that would result in evolutionary disequilibrium within subspecies. In the west, high observed heterozygosity values and evidence of gene flow suggest that population declines and patchy habitat, which currently imperil this species throughout much of its range, have not led to inbreeding or biologically meaningful genetic differentiation among the sampled populations.

Karyotype Evolution and Speciation in Lizards (Genus Sceloporus) During Evolution of the North American Desert

1967 ◽  
Vol 16 (4) ◽  
pp. 296 ◽  
Author(s):  
Charles H. Lowe ◽  
Charles J. Cole ◽  
James L. Patton
Keyword(s):  
North American ◽  
Karyotype Evolution ◽  
The North

scholarly journals Chromosomal change and rectangular evolution in North American cyprinid fishes

1980 ◽  
Vol 35 (2) ◽  
pp. 157-164 ◽  
Author(s):  
J. R. Gold
Keyword(s):  
North American ◽  
Evolutionary Biology ◽  
Chromosomal Evolution ◽  
Alternative View ◽  
Evolutionary Divergence ◽  
Genetic Changes ◽  
Chromosomal Change ◽  
Chromosomal Data ◽  
Cyprinid Fishes ◽  
Evolutionary Paths

SUMMARYAn important question in evolutionary biology concerns the manner and tempo in which organismal and/or genetic changes that promote evolutionary divergence occur. One recent hypothesis, termed rectangular evolution, holds that most significant evolutionary change occurs during occasional or periodic speciation episodes, with long periods of evolutionary stability in the interim. An alternative view, termed phyletic gradualism, holds that evolutionary divergences proceed by the slow and even accumulation of genetic differences within populations of established species. Two brief tests of rectangular evolution are presented using chromosomal data from North American cyprinid fishes (minnows), a group known to have experienced heterogeneous rates of splitting. Within the rapidly speciated genus Notropis, rates of chromosomal evolution appear slower relative to other, less rapidly speciated confamilial genera. Species of Notropis also are less divergent chromosomally, on the average, than are species from other cyprinid genera. These results are in compatible with a rectangular mode of chromosomal divergence these fishes. The results also reveal inconsistencies with a gradual mode chromosomal divergence, but at present this hypothesis cannot be falsified. Consideration of these and other data suggests that different levels of the cyprinid genome may follow independent evolutionary paths.

Cytogenetics of beavers: a case of speciation by monobrachial centric fusions

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 324-328 ◽  
Author(s):  
O. G. Ward ◽  
A. S. Graphodatsky ◽  
D. H. Wurster-Hill ◽  
V. R. Eremina ◽  
J. P. Park ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
North American ◽  
Karyotype Evolution ◽  
Castor Canadensis ◽  
The Other ◽  
Castor Fiber ◽  
Isolated Populations

A comparison of G-banded chromosomes of four North American beavers, Castor canadensis (two males, two females), and four Eurasian beavers, Castor fiber (two males, two females), revealed that extensive monobrachial centric fusions distinguished the karyotypes of the two species. The complex multivalent formations that would occur in meiosis of a hypothetical hybrid would be expected to produce unbalanced gametes and postmating reproductive isolation. Thus, neither species was derived from the other; rather, they likely were derived from isolated populations in which some of the acrocentrics fused independently to produce monobrachial homology.Key words: beaver, chromosomes, karyotype evolution, monobrachial rearrangements, reproductive isolation.

scholarly journals Engellaria (Caryophyllaceae), a new North American genus segregated from Stellaria

2021 ◽  
Author(s):  
Duilio Iamonico
Keyword(s):  
North American ◽  
Phenotypic Variability ◽  
Phylogenetic Analyses ◽  
Molecular Data ◽  
Morphological Data ◽  
Separate Genus ◽  
Plant Groups ◽  
Combined Use ◽  
Molecular Studies ◽  
Diagnostic Key

Background and Aims: Stellaria traditionally comprises 150-200 species, mainly distributed in the temperate regions of Eurasia and North America. Molecular studies demonstrated that Stellaria is polyphyletic and includes about 120 species. The genus has a high phenotypic variability which has led to nomenclatural disorders, making the identification of the various species difficult. A note is presented about a taxon currently accepted under the genus Stellaria -Stellaria obtusa- which should be recognized as a separate genus, here proposed as Engellaria gen. nov.Methods: This study is based on examination of specimens of American and European herbaria and analysis of relevant literature.Key results: Available molecular data show that Stellaria obtusa is not included in the Stellaria s.s. clade, but instead is basal to another clade comprising the genera Honckenya, Schiedea, and Wilhelmsia. Stellaria obtusa was, therefore, compared with these three groups and with morphologically similar apetalous members of Stellaria s.s. (S. crispa, S. media, S. pallida, and S. irrigua). The results obtained lead to the recognition of S. obtusa as a separate new North American monotypic genus. A diagnostic key of the apetalous members belonging to the American Caryophyllaceae genera is proposed. Finally, the names Stellaria obtusa and S. washingtoniana (= S. obtusa) are lectotypified based on specimens deposited, respectively, at UC (isolectotypes at GH, NY, and YU) and GH (isolectotypes at BM, CAN, CAS, CS, DOV, F, GH, K, MIN, MSC, NY, US, and VT). For the name Alsine viridula (= S. obtusa) the holotype was found at US (isotypes at CAS, F, GH, NY, OSC, RM, and UC).Conclusions: Stellaria obtusa does not belong to the genus Stellaria. The present study shows that the combined use of morphological data and phylogenetic analyses helped to clarify the taxonomic position of difficult plant groups, as in Stellaria.

scholarly journals Karyotype evolution and new chromosomal data in Erodium: chromosome alteration, polyploidy, dysploidy, and symmetrical karyotypes

2020 ◽  
Vol 44 (3) ◽  
pp. 255-268
Author(s):  
Esra MARTİN ◽  
Ahmet KAHRAMAN ◽  
Tuncay DİRMENCİ ◽  
Havva BOZKURT ◽  
Halil Erhan EROĞLU
Keyword(s):  
Karyotype Evolution ◽  
Chromosomal Data ◽  
Chromosome Alteration

Cytogenetic studies in North American minnows (Cyprinidae). XXII. Chromosomal nucleolar organizer regions in the genus Pimephales

1991 ◽  
Vol 69 (11) ◽  
pp. 2826-2830 ◽  
Author(s):  
Yucheng Li ◽  
John R. Gold
Keyword(s):  
North American ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Submetacentric Chromosome ◽  
The North ◽  
Extant Species ◽  
Previous Hypothesis ◽  
Chromosomal Data

Chromosomal nucleolar organizer region (NOR) phenotypes are documented for all four extant species in the North American cyprinid fish genus Pimephales. All four species (P. notatus, P. promelas, P. tenellus, and P. vigilax) possess 2n = 50 chromosomes and a pair of NOR-bearing chromosomes with the NOR situated terminally on the short arm of a medium-sized to large submetacentric chromosome (NOR phenotype C). Trypsin G-banding demonstrated that the C NOR chromosome in all four species is homologous. Two of the species (P. tenellus and P. promelas) also possess a C′ NOR chromosome, which is defined as an NOR situated terminally on the short arm of a large submetacentric chromosome that is also the largest chromosome in the complement. The C′ NOR chromosome occurs infrequently in P. promelas, being found in only 8% or so of all metaphases examined. Trypsin G-banding demonstrated that the C′ NOR chromosomes in the two Pimephales species are homologous to one another and to the C′ NOR chromosomes found in the cyprinid genus Cyprinella. A presumed derivative of the C′ NOR chromosome occurs in the monotypic cyprinid genus Opsopoeodus. The NOR chromosomal data support monophyly of the four extant species of Pimephales, and further suggest that the genus Pimephales belongs in a monophyletic assemblage with, among others, the cyprinid genera Cyprinella and Opsopoeodus. The data do not support the previous hypothesis that Pimephales is a basal clade outside of a larger assemblage of "Notropis"-like, shiners.

scholarly journals Karyotype analysis and karyological relationships of Turkish Bunium species (Apiaceae)

2020 ◽  
Vol 72 (2) ◽  
pp. 203-209
Author(s):  
Mustafa Çelik ◽  
Yavuz Bağcı ◽  
Esra Martin ◽  
Halil Eroğlu
Keyword(s):  
Ploidy Level ◽  
Chromosome Numbers ◽  
Karyotype Evolution ◽  
Karyotype Analysis ◽  
The Other ◽  
Monophyletic Group ◽  
Polyploid Species ◽  
Chromosomal Data ◽  
Group B ◽  
First Time

Chromosomal data and karyological relationships provide valuable information about karyotype evolution and speciation. For the genus Bunium, the chromosomal data are limited. In the present study, the chromosomal data of 10 taxa are provided, 6 of which are given for the first time, 2 present new chromosome numbers, and 2 agree with previous reports. Four different chromosome numbers (2n=18, 20, 22 and 40) were detected, and 2n=40 is a new number in the genus Bunium. B. brachyactis is the first polyploid species of the genus with a ploidy level of 4x. The most asymmetric karyotypes are those of B. pinnatifolium and B. sayae. Regarding karyological relationships, B. pinnatifolium forms a monophyletic group by quite different karyological features such as large chromosomes, more submedian chromosomes and the most asymmetric karyotypes. In addition, the other 5 taxa form a strong monophyletic group. B. verruculosum and B. ferulaceum are cytotaxonomically very close species, as are B. sayae and B. elegans var. elegans. The chromosome numbers of 2 Turkish species, B. nudum and B. sivasicum, remain unknown. The presented results provide important contributions to the cytotaxonomy of Bunium.

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