scholarly journals GENERALISTS, SPECIALISTS, AND THE EVOLUTION OF PHENOTYPIC PLASTICITY IN SYMPATRIC POPULATIONS OF DISTINCT SPECIES

Evolution ◽  
1997 ◽  
Vol 51 (5) ◽  
pp. 1372-1380 ◽  
Author(s):  
Peter H. van Tienderen
Keyword(s):  
Phenotypic Plasticity ◽  
Distinct Species ◽  
Sympatric Populations

A Genetic Comparison of Sympatric Populations of Sand Lance (Genus Ammodytes) from the Region East of Cape Soya, Japan

1989 ◽  
Vol 46 (11) ◽  
pp. 1945-1951 ◽  
Author(s):  
Hiroaki Okamoto
Keyword(s):  
Genetic Structure ◽  
Gel Electrophoresis ◽  
Distinct Species ◽  
The Other ◽  
Starch Gel Electrophoresis ◽  
Sympatric Populations ◽  
Sand Lance ◽  
Protein Coding ◽  
Starch Gel ◽  
Genetic Comparison

Sand fance (Genus Ammodytes) collected from four stations off Japan and one station at Kodiak, Alaska were genetically characterized at 17 protein coding loci using starch-gel electrophoresis. Sand lance in Wakkanai (Cape Soya, Japan) consist of two genetically distinct groups. They are fixed for different alleles at four loci (Ldh-2, -3, G3pdh-2, and Mdhp-2). The genetic structure of one of the groups (Wakkanai-a group, W-a) is similar to that of A. personatus around Japan. The other group (Wakkanai-b group, W-b) has different genetic structure from either A. personatus or the Alaskan collection, which is presumed to belong to A. hexapterus. It is not presently possible to identify the affiliation of the W-b group; however, despite its sympatry with the W-a group, it is reproductively isolated and therefore is probably a distinct species occurring northeast of Hokkaido.

Molecular and morphological evidence for and against gene flow in sympatric apomicts of the North American Crepis agamic complex (Asteraceae)This paper is one of a selection of papers published in the Special Issue on Systematics Research.

Botany ◽  
2008 ◽  
Vol 86 (8) ◽  
pp. 877-885 ◽  
Author(s):  
Jeannette Whitton ◽  
Katrina M. Dlugosch ◽  
Christopher J. Sears
Keyword(s):  
Gene Flow ◽  
North American ◽  
Distinct Species ◽  
The Other ◽  
Morphological Data ◽  
Morphological Evidence ◽  
Hybrid Zones ◽  
Sympatric Populations ◽  
Contact Zones ◽  
The North

The study of sympatric populations of closely related plant species often reveals evidence of hybridization. Mechanisms that reduce outcrossing (e.g., selfing, apomixis) may allow co-occurrence without gene flow. In this study, we describe patterns of genetic variation in two contact zones, each comprising three closely related morphological types, that key to three distinct species in the North American Crepis agamic (apomictic) complex. We used RAPD markers to characterize individuals from two sites: one in northern California (Sardine Lookout) and another in northwestern Oregon (Summit Road). At Sardine Lookout, we discerned a total of four multilocus genotypes, two in one species, and one each in the other two species. Our findings suggest that distinct morphological types are maintained by absolute barriers to gene flow at this site. At Summit Road, we found greater genotypic diversity, with a total of 24 genotypes across 30 individuals. One of the morphological types was clearly genetically differentiated from the other two, with no variable markers shared with other species at this site. The two remaining species showed evidence of gene flow, with no unique markers discerning them. Morphological data tend to support this conclusion, with univariate and multivariate analyses indicating a pattern of variation spanning the two species. Taken together, these patterns suggest that contact zones need not represent hybrid zones, and that apomixis can serve as an effective barrier to gene flow that may allow for stable coexistence of close relatives.

scholarly journals Cryptic species in Pagamea coriacea sensu lato (Rubiaceae): evidence from morphology, ecology and reproductive behavior in a sympatric context

2013 ◽  
Vol 43 (4) ◽  
pp. 415-428 ◽  
Author(s):  
Samantha de Miranda Esteves ◽  
Alberto Vicentini
Keyword(s):  
Multivariate Analyses ◽  
Habitat Preferences ◽  
Distinct Species ◽  
Canonical Discriminant Analysis ◽  
Sympatric Populations ◽  
Reproductive Behaviors ◽  
White Sand ◽  
Sexual Systems ◽  
Group A ◽  
Group B

In this study we explore morphological and ecological variation in sympatric populations of Pagamea coriacea s.l. - a species complex from white-sand vegetation in the Amazon. A total of 147 trees were sampled and monitored at three nearby sites in Central Amazon, Brazil. Multivariate analyses of morphology indicated two distinct groups (A and B), which also differed in bark type, each containing subgroups associated with sexual dimorphism. However, a single hermaphroditic individual was observed within group B. As expected, all pistillate plants produced fruits, but 23% of the staminate plants of group B, and 5% of group A also produced fruits. This variation suggests that the sexual systems of both groups are between dioecy and gynodioecy. There was an overlap in flowering phases between the two groups, but the pattern of floral maturation differed. Ecologically, plants of group B were found in more shaded habitats and over sandstone bedrocks, while group A was prevalent in deeper sandy soils as canopy plants. The significances of morphological and environmental differences were tested by a multivariate analysis of variance, and a canonical discriminant analysis assessed the importance of variables. The coexistence in sympatry of two discrete morphological groups in the P. coriacea s.l., with different habitat preferences and reproductive behaviors, indicates they represent distinct species.

Taxonomic reassessment of Gracilaria cearensis (Rhodophyta, Gracilariales), a poorly defined yet common flattened species based on morphological and molecular analysis including topotype collections

Phytotaxa ◽  
2015 ◽  
Vol 201 (4) ◽  
pp. 241 ◽  
Author(s):  
Luanda Pereira Soares ◽  
Carlos Frederico Deluqui Gurgel ◽  
Mutue Toyota Fujii
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Divergence ◽  
Sequence Divergence ◽  
Taxonomic Status ◽  
Original Description ◽  
Distinct Species ◽  
Molecular Data ◽  
Rbcl Gene ◽  
Similar Species ◽  
The World

The genus Gracilaria is the major source of agarose in the world today and is one of the most species-rich genera in the Rhodophyta. Flat Gracilaria species are among the most taxonomically challenging taxa due to their widespread phenotypic plasticity among all species. Gracilaria cearensis is a flat species described in 1965 from Brazil. Its original description is not conducive to accurate taxonomic identifications and the delineation of this taxon remains elusive. New samples of G. cearensis were collected across a coastal length of 500 km including its type locality. Universal Plastid Amplicon (UPA) and the rbcL gene were used to confirm the phylogenetic and taxonomic status of this poorly known species. Results showed that this is a distinct species despite morphological similarities to G. hayi, G. cuneata, G. curtissiae, G. brasiliensis and G. galetensis. G. cearensis is sister to G. hayi yet the genetic divergence between these two species was 2% for rbcL and 1.08% for UPA, enough to consider them distinct taxa. However, newly generated molecular data placed G. smithsoniensis, another morphologically similar species, as conspecific with G. cearensis with only 0.07% rbcL sequence divergence between them.

Hoplopleura ramgarh sp.nov. and Hoplopleura sinhgarh sp.nov. (Anoplura: Hoplopleuridae), parasitizing Mus spp. (Rodentia: Muridae) in India

Parasitology ◽  
1972 ◽  
Vol 65 (1) ◽  
pp. 11-21 ◽  
Author(s):  
A. C. Mishra ◽  
H. R. Bhat ◽  
S. M. Kulkarni
Keyword(s):  
Western Ghats ◽  
Distinct Species ◽  
North India ◽  
Sympatric Populations ◽  
Peninsular India ◽  
Closely Related Species ◽  
Western Himalayan Region ◽  
Two New Species ◽  
Taxonomical Status ◽  
The Western Ghats

Two new species of the genus Hoplopleura are described from two closely related species of the genus Mus. H. ramgarh sp.nov. was found parasitizing Mus platythrix Bennett, 1932, in the Western Himalayan region in North India and in the Western Ghats in Peninsular India. H. sinhgarh sp.nov. was found parasitizing a species of the genus Mus, closely related to M. platythrix, and occurring sympatrically with it. The exact taxonomical status of this rodent species is still under investigation. The occurrence of two distinct species of lice on closely related sympatric populations of these mice has given an indication of their being two distinct taxa, a fact later supplemented by some consistent but not easily delineable skin and skull characters.

A Systematic Study of the Salvelinus alpinus Complex in North America

1961 ◽  
Vol 18 (5) ◽  
pp. 793-816 ◽  
Author(s):  
J. D. McPhail
Keyword(s):  
North America ◽  
Systematic Study ◽  
Discriminant Function Analysis ◽  
Salvelinus Alpinus ◽  
Function Analysis ◽  
Distinct Species ◽  
Sympatric Populations ◽  
Origin And Evolution ◽  
Kodiak Island ◽  
Salvelinus Alpinus Complex

Sympatric populations of Salvelinus malma and Salvelinus alpinus from Karluk and Fraser Lakes, Kodiak Island, Alaska, were compared using the discriminant function analysis. The analysis indicated that hybridization between S. malma and S. alpinus rarely, if ever, occurs in these lakes. Therefore, S. malma and S. alpinus are considered distinct species. Data on 507 S. malma and 411 S. alpinus from 77 localities suggest at least two distinct forms of both S. malma and S. alpinus in North America. Speculations are made on the origin and evolution of S. malma and S. alpinus.

scholarly journals Integrative taxonomy confirms that Gregarina garnhami and G. acridiorum (Apicomplexa, Gregarinidae), parasites of Schistocerca gregaria and Locusta migratoria (Insecta, Orthoptera), are distinct species

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 12
Author(s):  
Isabelle Florent ◽  
Marie Pierre Chapuis ◽  
Amandine Labat ◽  
Julie Boisard ◽  
Nicolas Leménager ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Morphological Study ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Geographical Location ◽  
Distinct Species ◽  
Integrative Taxonomy ◽  
Ssu Rdna ◽  
Molecular Analyses ◽  
Orthopteran Species

Orthoptera are infected by about 60 species of gregarines assigned to the genus Gregarina Dufour, 1828. Among these species, Gregarina garnhami Canning, 1956 from Schistocerca gregaria (Forsskål, 1775) was considered by Lipa et al. in 1996 to be synonymous with Gregarina acridiorum (Léger 1893), a parasite of several orthopteran species including Locusta migratoria (Linné, 1758). Here, a morphological study and molecular analyses of the SSU rDNA marker demonstrate that specimens of S. gregaria and specimens of L. migratoria are infected by two distinct Gregarina species, G. garnhami and G. acridiorum, respectively. Validation of the species confirms that molecular analyses provide useful taxonomical information. Phenotypic plasticity was clearly observed in the case of G. garnhami: the morphology of its trophozoites, gamonts and syzygies varied according to the geographical location of S. gregaria and the subspecies infected.

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.

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