A cytotaxonomic study of Australian Cardamine

1968 ◽  
Vol 16 (3) ◽  
pp. 515 ◽  
Author(s):  
N Thurling
Keyword(s):  
Reproductive Isolation ◽  
Native Species ◽  
Cytogenetic Study ◽  
Morphological Differentiation ◽  
Distinct Species ◽  
The Other ◽  
F1 Hybrids ◽  
Altitudinal Distribution ◽  
South Wales ◽  
Morphological Differences

A cytogenetic study of Cardamine, based on material collected in southern New South Wales and the Australian Capital Territory, indicated the presence of at least six distinct species in this area. Two species, the 16-chromosome C. hirsuta and the 32- chromosome C. flexuosa, were introduced with white settlement. The other four species are native to the area, occupying a variety of habitats between sea-level and 7200 ft. One species, with a somatic chromosome number of 64, is confined to altitudes below 4000 ft, whereas the other three species (2n = 48) are found only above 4000 ft. Of the 48-chromosome species, one comprises a single population found at Mt. Franklin and the remaining two are confined to particular altitudinal ranges, one between 4000 and 5400 ft and the other between 5200 and 7200 ft. All four native species are completely isolated from one another by the inviability of the F1 hybrids. Within species, however, all populations were fully interfertile and there was no evidence of any other form of reproductive isolation. Despite the magnitude of reproductive isolation there were no distinct morphological differences between the native species except in the case of the 48-chromosome form from Mt. Franklin, which had entire rather than pinnate leaves. The other three species were in fact more comparable to ecotypes in respect of their altitudinal distribution and the degree of morphological differentiation. Speciation mechanisms involved in the evolution of the native species of Cardamine are discussed.

A taxonomic reevaluation of North American Daphnia (Crustacea: Cladocera). I. The D. similis complex

1993 ◽  
Vol 71 (5) ◽  
pp. 908-925 ◽  
Author(s):  
Paul D. N. Hebert ◽  
Terrie L. Finston
Keyword(s):  
Species Recognition ◽  
Distinct Species ◽  
The Other ◽  
Allozyme Analysis ◽  
Distance Analysis ◽  
Daphnia Similis ◽  
Cyclic Parthenogenesis ◽  
Morphological Differences ◽  
Genetic Distance Analysis

Allozyme analysis of 28 populations of Daphnia similis s.l. from the western United States and Canada indicated the presence of three different species. One taxon, D. salina, is newly described and a second species, D. exilis, previously synonymized with D. similis, is also shown to be distinct. Species recognition is not solely reliant on allozyme analysis, as morphological differences among the species are conspicuous. Daphnia salina is a halophile, while the other two species occur in habitats of lower but variable salinity. All three taxa appear to reproduce by cyclic parthenogenesis, although levels of genetic diversity were so low in D. salina that determination of its breeding system was tentative. Genetic distance analysis suggested that D. salina diverged from the other two species some 27 million years ago, whereas D. exilis and D. similis separated 9 million years ago.

scholarly journals Are genetically distinct lizard species able to hybridize? A review

2015 ◽  
Vol 61 (1) ◽  
pp. 155-180 ◽  
Author(s):  
Jitka Jančúchová-Lásková ◽  
Eva Landová ◽  
Daniel Frynta
Keyword(s):  
Reproductive Isolation ◽  
Genetic Divergence ◽  
Divergence Time ◽  
Distinct Species ◽  
F1 Hybrids ◽  
Lizard Species ◽  
And Bisexual ◽  
Reproductive Isolation Mechanisms ◽  
Cyt B Gene ◽  
The Relationship

Abstract Animal species are delimited by reproductive isolation mechanisms (RIMs). Postzygotic RIMs are mainly products of genetic differences and thus their strength increases with elapsed divergence time. The relationship between postzygotic reproductive isolation and genetic divergence, however, differs considerably among major clades of vertebrates. We reviewed the available literature providing empirical evidence of natural and/or experimental hybridization between distinct species of lizards (squamates except snakes). We found that hybridization events are widely distributed among nearly all major lizard clades. The majority of research focuses on parthenogenetic species and/or polyploid hybrids in families Lacertidae, Teiidae and Gekkonidae. Homoploid bisexual hybrids are mainly reported within Lacertidae and Iguania groups. As a proxy of genetic divergence of the hybridizing taxa we adopted nucleotide sequence distance (HKY85) of mitochondrial cyt b gene. The upper limit of genetic divergence was similar with regard to both parthenogenetic and bisexual hybrids. Maximum values of these distances between hybridizing species of lizards approached 18%?21%, which is comparable to or even exceeds the corresponding values reported for other principal clades of vertebrates. In spite of this, F1 hybrids are typically at least partially fertile in lizards and thus genetic in-trogression between highly divergent species is possible. The relationship between the genetic distance and hybrid fertility was not found.

Emended description and resurrection of Sciaphila tosaensis and S. megastyla (Triuridaceae)

Phytotaxa ◽  
2019 ◽  
Vol 413 (3) ◽  
pp. 231-243 ◽  
Author(s):  
KENJI SUETSUGU ◽  
AKIHIKO KINOSHITA ◽  
TIAN-CHUAN HSU
Keyword(s):  
Genetic Divergence ◽  
Taxonomic Status ◽  
Distinct Species ◽  
Molecular Data ◽  
Genetic Distances ◽  
The Other ◽  
Morphological Data ◽  
Flowering Stage ◽  
Emended Description ◽  
Morphological Differences

This paper presents a re-evaluation of the taxonomic status of Sciaphila tosaensis and S. megastyla (Triuridaceae) distributed in Japan and Taiwan. Based on the detailed morphological data, we concluded that these two species should both be treated as distinct species rather than synonyms of S. secundiflora. Sciaphila tosaensis differs from S. secundiflora and S. megastyla in having very narrow male perianth segments and female perianth segments distinctly shorter than male perianth segments. Sciaphila megastyla differs from the other two species in having very conspicuous style and stigma that is ca. 1.5 times as long as ovary in the flowering stage. Furthermore, a lectotype is designated of S. megastyla because its holotype has been lost. Molecular data also showed that there is considerable genetic divergence between S. tosaensis and S. megastyla, supporting that the morphological differences are mirrored by their genetic distances.

The Litoria ewingi complex (Anura : Hylidae) in south-eastern Australia I A new species from Victoria

1971 ◽  
Vol 19 (4) ◽  
pp. 401 ◽  
Author(s):  
GF Watson ◽  
JJ Loftus-Hills ◽  
MJ Littlejohn
Keyword(s):  
New Species ◽  
Reproductive Isolation ◽  
Morphological Differentiation ◽  
The North ◽  
Isolating Mechanisms ◽  
Eastern Australia ◽  
North Eastern ◽  
Morphological Differences ◽  
High Level ◽  
A New Species

Populations of the L. ewingi complex in central and north-eastern Victoria are described as a new species (L. paraewingi) following a study of levels of reproductive isolation and morphological differentiation from other members of the complex. In the south the new species is broadly sympatric with L. verreauxi, but is contiguously allopatric with L. ewingi at the north-eastern and south-western borders of its distribution. Pre-mating isolating mechanisms between L, paraewingi and L. ewingi are not well developed; however, a high level of post-mating isolation exists between the two species. Morphological differences were found between L. paraewingi and populations of L. ewingi from southern Victoria and Tasmania, but populations in north-eastern Victoria are morphologically similar.

scholarly journals Integrative taxonomy resuscitates two species in the Lasioglossum villosulum complex (Kirby, 1802) (Hymenoptera: Apoidea: Halictidae)

2019 ◽  
Author(s):  
Alain Pauly ◽  
Grégoire Noël ◽  
Gontran Sonet ◽  
David G. Notton ◽  
Jean-Luc Boevé
Keyword(s):  
Bayesian Inference ◽  
Species Complex ◽  
Phylogenetic Trees ◽  
Dna Barcode ◽  
Distinct Species ◽  
Integrative Taxonomy ◽  
The Other ◽  
Candidate Species ◽  
Morphological Differences ◽  
Pseudocryptic Species

Morphological and allozyme analyses suggested the occurrence of a pseudocryptic species in the Lasioglossum villosulum (Kirby, 1802) species complex (Hymenoptera: Halictidae). We analysed the morphology of more than 1500 specimens and the DNA barcode fragment of the cytochrome c oxidase subunit I (COI) of 102 specimens of this species complex from several Palaearctic countries. Our phylogenetic tree reconstructions, based on maximum likelihood and Bayesian inference revealed one clade corresponding to all specimens morphologically identified as Lasioglossum medinai (Vachal, 1895) and one divergent specimen morphologically identified as Lasioglossum berberum (Benoist, 1941). The other specimens, morphologically identified as L. villosulum, aggregated into at least three other lineages in our phylogenetic trees. The tree-based species delineations methods based on the Generalized Mixed Yule Coalescent (GMYC) model and the Bayesian Poisson Tree Process (bPTP) identified five to ten candidate species within the L. villosulum species complex, with L. medinai and L. berberum consistently recognized as separated from all other candidate species. Diagnostic morphological differences were found among L. medinai, L. berberum and the remaining specimens identified as L. villosulum. No diagnostic morphological differences were found to distinguish the different phylogenetic candidate species or lineages found within L. villosulum and L. medinai. Thus, both genetic and morphological approaches support the existence of L. medinai and L. berberum as distinct species from L. villosulum.

A scanning electron microscopic study of the eggs of Culicoides variipennis (Diptera: Ceratopogonidae)

1987 ◽  
Vol 45 ◽  
pp. 884-885 ◽  
Author(s):  
R. A. Nunamaker ◽  
C. E. Nunamaker ◽  
B. C. Wick
Keyword(s):  
Distinct Species ◽  
Hemorrhagic Disease ◽  
Insect Vector ◽  
Electron Microscopic ◽  
Important Species ◽  
Scanning Electron Microscopic Study ◽  
Laboratory Colony ◽  
Culicoides Variipennis ◽  
Morphological Differences ◽  
Scanning Electron

Culicoides variipennis (Coquillett) is probably the most economically important species of biting midge in the U.S. due to its involvement in the transmission of bluetongue (BT) disease of sheep, cattle and ruminant wildlife, and epizootic hemorrhagic disease (EHD) of deer. Proposals have been made to recognize the eastern and western populations of this insect vector as distinct species. Others recommend use of the term “variipennis complex” until such time that the necessary biosystematic studies have been made to determine the genetic nature and/or minute morphological differences within the population structure over the entire geographic range of the species. Increasingly, students of ootaxonomy are relying on scanning electron microscopy (SEM) to assess chorionic features. This study was undertaken to provide comparative chorionic data for the C. variipennis complex.Culicoides variipennis eggs were collected from a laboratory colony maintained in Laramie, Wyoming.

Status of Family Fissidentaceae in Gujarat

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
D.G. Shah ◽  
D.N. Mehta ◽  
R.V. Gujar
Keyword(s):  
Distinct Species ◽  
The State ◽  
The Other ◽  
Land Plants ◽  
Reproductive Structures ◽  
The Family ◽  
The Status ◽  
Vegetative Characters ◽  
First Time ◽  
Different Parts

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.

scholarly journals Selective pollination by fungus gnats potentially functions as an alternative reproductive isolation among five Arisaema species

2020 ◽  
Author(s):  
Tetsuya K Matsumoto ◽  
Muneto Hirobe ◽  
Masahiro Sueyoshi ◽  
Yuko Miyazaki
Keyword(s):  
Reproductive Isolation ◽  
Altitudinal Gradient ◽  
Flowering Phenology ◽  
Altitudinal Distribution ◽  
Interspecific Differences ◽  
Flower Visitation ◽  
Fungus Gnats ◽  
Floral Visitor ◽  
Floral Visitors ◽  
Experimental Plots

Abstract Background and Aims Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. Methods We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established 10 experimental plots including the five Arisaema species on high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using the unified formula for reproductive isolation. Key Results Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots, and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. Conclusions Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

Quantitative Trait Loci Affecting Differences in Floral Morphology Between Two Species of Monkeyflower (Mimulus)

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 367-382 ◽  
Author(s):  
H D Bradshaw ◽  
Kevin G Otto ◽  
Barbara E Frewen ◽  
John K McKay ◽  
Douglas W Schemske
Keyword(s):  
Quantitative Trait Loci ◽  
Reproductive Isolation ◽  
Quantitative Trait ◽  
Floral Morphology ◽  
Cumulative Effect ◽  
Sympatric Species ◽  
Accurate Estimate ◽  
Phenotypic Variance ◽  
Trait Loci ◽  
Morphological Differences

Abstract Conspicuous differences in floral morphology are partly responsible for reproductive isolation between two sympatric species of monkeyflower because of their effect on visitation of the flowers by different pollinators. Mimulus lewisii flowers are visited primarily by bumblebees, whereas M. cardinalis flowers are visited mostly by hummingbirds. The genetic control of 12 morphological differences between the flowers of M. lewisii and M. cardinalis was explored in a large linkage mapping population of F2 plants (n = 465) to provide an accurate estimate of the number and magnitude of effect of quantitative trait loci (QTLs) governing each character. Between one and six QTLs were identified for each trait. Most (9/12) traits appear to be controlled in part by at least one major QTL explaining ≥25% of the total phenotypic variance. This implies that either single genes of individually large effect or linked clusters of genes with a large cumulative effect can play a role in the evolution of reproductive isolation and speciation.

Powerline Easements: Do They Promote Edge Effects in Eucalypt Forest for Small Mammals?

1997 ◽  
Vol 24 (6) ◽  
pp. 737 ◽  
Author(s):  
Ross L. Goldingay ◽  
Robert J. Whelan
Keyword(s):  
Small Mammals ◽  
Edge Effects ◽  
Native Species ◽  
Vegetative Cover ◽  
Mammal Species ◽  
Terrestrial Mammals ◽  
Eucalypt Forest ◽  
Hair Sampling ◽  
South Wales ◽  
Antechinus Stuartii

The distribution and abundance of small terrestrial mammals were assessed in forest adjacent to powerline easements at three different sites in New South Wales. At each site, four transects of 300 m length extended into the forest from the edge of the easement. The abundances of two native species (Antechinus stuartii, Rattus fuscipes) did not differ significantly with distance from the easement but abundances differed markedly among sites. Mammals were captured in only one easement where dense vegetation was present. Feral carnivores, which may mediate edge effects on small mammals, were surveyed by using hair-sampling tubes. Cats and dogs were detected only 50–200 m inside the forest. Foxes were not detected by hair-tubes but were observed on two easements. These results suggest that powerline easements may not create edge effects in eucalypt forest for some native mammal species, although further studies are needed to determine the generality of this conclusion. We recommend that easement management should be more benign to native mammals, given the ubiquity of this form of habitat fragmentation. Promotion of dense vegetative cover and habitat linkages within easements could achieve this.

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