scholarly journals Geographic and Ecological Dimensions of Host Plant-Associated Genetic Differentiation and Speciation in the Rhagoletis cingulata (Diptera: Tephritidae) Sibling Species Group

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 275 ◽  
Author(s):  
Doellman ◽  
Schuler ◽  
Jean ◽  
Hood ◽  
Egan ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Sibling Species ◽  
Adaptive Radiation ◽  
Ecological Theory ◽  
Species Group ◽  
Secondary Contact ◽  
Similar Species ◽  
Isolated Populations ◽  
Ecological Diversification ◽  
Postzygotic Reproductive Isolation

Ascertaining the causes of adaptive radiation is central to understanding how new species arise and come to vary with their resources. The ecological theory posits adaptive radiation via divergent natural selection associated with novel resource use; an alternative suggests character displacement following speciation in allopatry and then secondary contact of reproductively isolated but ecologically similar species. Discriminating between hypotheses, therefore, requires the establishment of a key role for ecological diversification in initiating speciation versus a secondary role in facilitating co-existence. Here, we characterize patterns of genetic variation and postzygotic reproductive isolation for tephritid fruit flies in the Rhagoletis cingulata sibling species group to assess the significance of ecology, geography, and non-adaptive processes for their divergence. Our results support the ecological theory: no evidence for intrinsic postzygotic reproductive isolation was found between two populations of allopatric species, while nuclear-encoded microsatellites implied strong ecologically based reproductive isolation among sympatric species infesting different host plants. Analysis of mitochondrial DNA suggested, however, that cytoplasmic-related reproductive isolation may also exist between two geographically isolated populations within R cingulata. Thus, ecology associated with sympatric host shifts and cytoplasmic effects possibly associated with an endosymbiont may be the key initial drivers of the radiation of the R. cingulata group.

Identity of the oribatid mite Oribata curva and transfer to Trichogalumna (Acari, Oribatida, Galumnidae), with discussion of nomenclatural and biogeographical issues in the ‘curva’ species-group

Zootaxa ◽  
2017 ◽  
Vol 4272 (4) ◽  
pp. 551
Author(s):  
ROY A. NORTON ◽  
SERGEY G. ERMILOV
Keyword(s):  
North America ◽  
Oribatid Mite ◽  
Species Group ◽  
Type Material ◽  
Similar Species ◽  
History Of ◽  
Molecular Assessment

Based on the study of type material, other historical specimens, and new collections, the adult of the thelytokous oribatid mite Oribata curva Ewing, 1907 (Galumnidae) is redescribed and the name is recombined to Trichogalumna curva (Ewing, 1907) comb. nov. A confusing history of synonymies and misidentifications is traced in detail, and their effect on published statements about biogeography is assessed. Reliable records of T. curva are only those from North America. The tropical mite Pergalumna ventralis (Willmann, 1932) is not a subspecies of T. curva. The widely-reported Trichogalumna nipponica (Aoki, 1966) and other similar species form a complex with T. curva that needs further morphological and molecular assessment. 

scholarly journals Adaptive radiation and hybridization in Wallace's Dreamponds: evidence from sailfin silversides in the Malili Lakes of Sulawesi

2006 ◽  
Vol 273 (1598) ◽  
pp. 2209-2217 ◽  
Author(s):  
Fabian Herder ◽  
Arne W Nolte ◽  
Jobst Pfaender ◽  
Julia Schwarzer ◽  
Renny K Hadiaty ◽  
...  
Keyword(s):  
New Species ◽  
Adaptive Radiation ◽  
Introgressive Hybridization ◽  
Reticulate Evolution ◽  
Species Group ◽  
Potential Force ◽  
Major Interest ◽  
Key Factor ◽  
Adaptive Radiations ◽  
Malili Lakes

Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization is a prominent phenomenon in the radiation of sailfin silversides (Teleostei: Atheriniformes: Telmatherinidae) inhabiting the ancient Malili Lakes of Sulawesi, correlating conspicuously with patterns of increased diversity. We found the most diverse lacustrine species-group of the radiation to be heavily introgressed by genotypes originating from streams of the lake system, an effect that has masked the primary phylogenetic pattern of the flock. We conclude that hybridization could have acted as a key factor in the generation of the flock's spectacular diversity. To our knowledge, this is the first empirical evidence for massive reticulate evolution within a complex animal radiation.

The speciation continuum and species relations between populations: in search of agreement between the theory and practice of systematics

2021 ◽  
pp. 173-179
Author(s):  
Oleksandr Zinenko
Keyword(s):  
Reproductive Isolation ◽  
Species Concept ◽  
Climatic Conditions ◽  
Point Of View ◽  
Theory And Practice ◽  
Hybrid Origin ◽  
Isolated Populations ◽  
As Species ◽  
Mitochondrial Cytochrome B ◽  
Traditional Taxonomy

From an evolutionary point of view, the achievement of species status by a group of populations is an ongoing process (except for rare cases of instantaneous speciation), during which isolated populations acquire traits and adaptations that minimize gene flow between them. However, depending on the group, the ways and timing of the gaining of reproductive isolation may be different. In such a complex group for systematics as small vipers (genus Vipera, subgenus Pelias), there are a number of problematic situations for species delimitation: the ability to form hybrids and hybrid populations between species, adaptive hybridization and hybrid speciation, and possible traces of reversed speciation, which indicate that complete and irreversible reproductive isolation may not be achieved at all. The effectiveness of reproductive isolation largely depends on external factors, mostly related to the range spatial structure, ecology of species in areas of sympatry, as well as climatic conditions and their changes, landscape dynamics, etc. The only species concept that allows to describe new species in the absence of reproductive isolation, recognizes the possibility of hybrid and reverse speciation — de Queiroz unified species concept — is practically unsuitable due to the need to consider as species a large number of isolated populations. Therefore, the solution is a conservative approach in practical taxonomy, which takes into account as a species criterion the ecological divergence of species, the possibility of their sympatric existence, which is usually achieved at 5% divergence of the mitochondrial cytochrome b gene. Stabilized hybrid populations occupying distinct ecological niche different from those of parental species also deserve recognition as species of hybrid origin. Not only species deserves to be protected, but also a distinguishable and diverged group of populations — Evolutionary Significant Unit (ESU) or subspecies in traditional taxonomy.

Chirocephalus sanhadjaensis sp. nov., a new chirocephalid species (Branchiopoda: Anostraca) from Numidia (Algeria)

Zootaxa ◽  
2018 ◽  
Vol 4526 (3) ◽  
pp. 381
Author(s):  
LYLIA BOUMENDJEL ◽  
NICOLAS RABET ◽  
MOUNIA AMAROUAYACHE
Keyword(s):  
New Species ◽  
Biological Diversity ◽  
Resting Eggs ◽  
Species Group ◽  
Similar Species ◽  
New Taxon ◽  
Freshwater Ponds ◽  
Restricted Distribution ◽  
A New Species ◽  
Northeastern Algeria

A new species of Chirocephalus collected in temporary freshwater ponds in Northeastern Algeria is described. Chirocephalus sanhadjaensis sp. nov. seems to be restricted to Ain-Magroun and Belkroun pools (Skikda Province). The most similar species is C. marchesonii Ruffo & Vesentini, 1957, which is endemic to Italy. The new taxon, belonging to the “diaphanus” species group of the genus Chirocephalus, is identifiable from all congeners primarily by the shape of the antennal appendages and that of the apex of the distal antennomere of the antennae. The resting eggs of C. sanhadjaensis sp. nov. are similar to those of C. diaphanus or C. salinus but are larger (448.24 ± 30.93 µm). The restricted distribution of this species confirms the high biological diversity of the area of the Guerbes-Sanhadja eco-complex. 

scholarly journals How Can Satellite DNA Divergence Cause Reproductive Isolation? Let Us Count the Chromosomal Ways

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Patrick M. Ferree ◽  
Satyaki Prasad
Keyword(s):  
Reproductive Isolation ◽  
Developmental Stages ◽  
Rapid Evolution ◽  
Model Organisms ◽  
Cellular Mechanisms ◽  
Closely Related Species ◽  
Heterochromatin Formation ◽  
Interspecies Hybrids ◽  
Postzygotic Reproductive Isolation ◽  
And Function

Satellites are one of the most enigmatic parts of the eukaryotic genome. These highly repetitive, noncoding sequences make up as much as half or more of the genomic content and are known to play essential roles in chromosome segregation during meiosis and mitosis, yet they evolve rapidly between closely related species. Research over the last several decades has revealed that satellite divergence can serve as a formidable reproductive barrier between sibling species. Here we highlight several key studies on Drosophila and other model organisms demonstrating deleterious effects of satellites and their rapid evolution on the structure and function of chromosomes in interspecies hybrids. These studies demonstrate that satellites can impact chromosomes at a number of different developmental stages and through distinct cellular mechanisms, including heterochromatin formation. These findings have important implications for how loci that cause postzygotic reproductive isolation are viewed.

Genetic Differentiation in Isolated Populations of Hakea carinata (Proteaceae)

1998 ◽  
Vol 46 (6) ◽  
pp. 671 ◽  
Author(s):  
G. J. Starr ◽  
S. M. Carthew
Keyword(s):  
Gene Flow ◽  
Habitat Fragmentation ◽  
Gene Diversity ◽  
South Australia ◽  
Similar Species ◽  
Isolated Populations ◽  
Plant Populations ◽  
Evolutionary Condition ◽  
Private Alleles

Fragmentation of the landscape by human activity has created small, isolated plant populations. Hakea carinata F. Muell. ex Meissner, a sclerophyllous shrub, is common in isolated fragments of vegetation in South Australia. This study investigated whether habitat fragmentation has caused restrictions to gene flow between populations. Gene diversity (HT = 0.317) is average for similar species but little is held within populations (HS = 0.168) and 46.9% of gene diversity is accounted for between populations. Estimates of gene flow are NM = 0.270 (based on FST) and NM = 0.129 (based on private alleles). Populations are substantially selfing (t = 0.111). Small isolated populations appears to be a long-term evolutionary condition in this species rather than a consequence of habitat fragmentation; however, population extinctions are occurring. Conservation will require the reservation of many populations to represent the genetic variation present in the species.

A revision of the Anthaxia (Anthaxia) midas Kiesenwetter, 1857 species-group (Coleoptera: Buprestidae: Anthaxiini)

Zootaxa ◽  
2018 ◽  
Vol 4370 (3) ◽  
pp. 201
Author(s):  
DANIELE BAIOCCHI ◽  
GIANLUCA MAGNANI
Keyword(s):  
New Species ◽  
Original Data ◽  
Species Group ◽  
Taxonomic Position ◽  
Similar Species ◽  
Type Specimens ◽  
Diagnostic Characters ◽  
Definition Of ◽  
A New Species ◽  
Unknown Male

The Anthaxia (Anthaxia) midas Kiesenwetter, 1857 species-group is defined and revised. A new species from Turkey, A. (A.) cebecii sp. nov., is described and compared to its most similar species. A. midas oberthuri Schaefer, 1938 is elevated to the rank of species, and a lectotype is designated. A. (A.) spathuligera Obenberger, 1924 and A. (A.) midas muelleri Obenberger, 1925 are reconfirmed synonyms of A. midas Kiesenwetter, 1857.All species of the new species-group are illustrated, including the hitherto unknown male of A. (A.) patsyae Baiocchi, 2008, all type specimens and original data labels. In addition to diagnostic characters, informations on the distribution, biology and taxonomic position of each species are also presented, together with a short definition of the new species-group, and a key to its species. 

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