scholarly journals Gammarus Fossarum Koch, 1835: Redescription Based on Neotype Material and Notes on its Local Variation (Crustacea, Amphipoda)

1972 ◽  
Vol 42 (2) ◽  
pp. 124-138 ◽  
Author(s):  
Annemarie Goedmakers
Keyword(s):  
Geographic Variation ◽  
Local Variation ◽  
Morphological Characters ◽  
Gammarus Fossarum ◽  
Different Populations

A redescription of Gammarus fossarum Koch, 1835, is given, together with some notes on the variability in morphological characters of this species, both within one population and in different populations. It is proved through crosses that five morphologically different populations all belong to the same species, G. fossarum. The geographic variation of the various characters is discussed.

CYTOTAXONOMY OF CONOPHTHORUS (COLEOPTERA: SCOLYTIDAE) IN EASTERN NORTH AMERICA

1990 ◽  
Vol 122 (6) ◽  
pp. 1131-1135 ◽  
Author(s):  
Peter de Groot ◽  
Terry J. Ennis
Keyword(s):  
North America ◽  
Geographic Variation ◽  
Distinct Species ◽  
Morphological Characters ◽  
Eastern North America ◽  
Supernumerary Chromosomes ◽  
Karyotypic Formula ◽  
Different Populations ◽  
Conophthorus Coniperda

AbstractThe male meiotic karyotypic formula of Conophthorus coniperda (Schwarz) (Coleoptera: Scolytidae) is 9AA + XY. This karyotype differs from C. resinosae Hopkins and C. banksianae McPherson, both of which have the karyotypic formula of 8AA + XY. Supernumerary chromosomes were found in different populations of C. resinosae and C. banksianae but were absent in C. coniperda. No geographic variation in the karyotypes of the three species was observed. The karyotypic formulae confirm the designations of C. coniperda and C. resinosae by morphological characters, but do not support the designation of C. banksianae as a distinct species.

Geographic variation in morphology of the genus Agamura Blanford, 1874 in Iran

2017 ◽  
Vol 38 (4) ◽  
pp. 449-459 ◽  
Author(s):  
Seyyed Saeed Hosseinian Yousefkhani ◽  
Mansour Aliabadian ◽  
Eskandar Rastegar-Pouyani ◽  
Jamshid Darvish
Keyword(s):  
Geographic Variation ◽  
Function Analysis ◽  
Principal Component ◽  
Morphological Characters ◽  
Correct Classification ◽  
Meristic Characters ◽  
Iranian Plateau ◽  
Different Populations ◽  
Head Height ◽  
Two Populations

The genusAgamurawas previously known from four species occurring on the Iranian Plateau, but was recently revised as a monotypic genus that excluded three species. In the present study, we examined different populations ofAgamura persicamorphologically. We found thatA. persicashows geographic variation with respect to two groups, with the eastern population considered asA. cruralisandA. persicaproposed for the western population. Separation between the two populations ofA. persicawas verified based upon ANOVA results for many morphological characters, including Head Height (HH), Interorbital distance (IO), Forelimb length (FLL), Number of scales across widest part of abdomen (NSA), Loreal scales (LOS), and Number of scales that separate two adjacent tubercles (NTV). Principal Component Analysis (PCA) and Discriminant Function Analysis (DFA) based on metric and meristic characters confirmed the revision of the genusAgamura. Multivariate analysis indicated that all studied OTUs were assigned to the correct classification and have significantly different morphological characters.

Integrative taxonomic and geographic variation analyses in Cyrtodactylus aequalis (Squamata: Gekkonidae) from southern Myanmar (Burma): one species, two different stories

2020 ◽  
Vol 66 (3-4) ◽  
pp. 151-179
Author(s):  
L. Lee Grismer ◽  
L. Wood Perry ◽  
Marta S. Grismer ◽  
Evan S.H. Quah ◽  
Myint Kyaw Thura ◽  
...  
Keyword(s):  
Geographic Variation ◽  
Evolutionary History ◽  
Phylogenetic Inference ◽  
Morphological Characters ◽  
Molecular Data ◽  
Biodiversity Crisis ◽  
Allopatric Populations ◽  
Compelling Argument ◽  
Historical Accuracy ◽  
Molecular Phylogenetic

The historical accuracy of building taxonomies is improved when they are based on phylogenetic inference (i.e., the resultant classifications are less apt to misrepresent evolutionary history). In fact, taxonomies inferred from statistically significant diagnostic morphological characters in the absence of phylogenetic considerations, can contain non-monophyletic lineages. This is especially true at the species level where small amounts of gene flow may not preclude the evolution of localized adaptions in different geographic areas while underpinning the paraphyletic nature of each population with respect to the other. We illustrate this point by examining genetic and morphological variation among three putatively allopatric populations of the granite-dwelling Bent-toed Gecko Cyrtodactylus aequalis from hilly regions in southeastern Myanmar. In the absence of molecular phylogenetic inference, a compelling argument for three morphologically diagnosable species could be marshaled. However, when basing the morphological analyses of geographic variation on a molecular phylogeny, there is a more compelling argument that only one species should be recognized. We are cognizant of the fact however, that when dealing with rare species or specimens for which no molecular data are possible, judicious morphological analyses are the only option—and the desired option given the current worldwide biodiversity crisis.

Diversity among different populations of a locally common rice (Oryza sativa L.) landrace from north-western Indian Himalayas

2010 ◽  
Vol 8 (2) ◽  
pp. 151-158 ◽  
Author(s):  
S. Kumar ◽  
A. Pandey ◽  
I. S. Bisht ◽  
K. V. Bhat ◽  
P. S. Mehta
Keyword(s):  
Oryza Sativa ◽  
Oryza Sativa L ◽  
Morphological Characters ◽  
Ex Situ ◽  
Evolutionary Forces ◽  
Minimum Number ◽  
Environmental Adaptations ◽  
Farmer Management ◽  
Different Populations ◽  
On Farm

Genetic structure of five populations of a locally common rice (Oryza sativa L.) landrace Jaulia from parts of Uttarakhand state of India was studied using sequence tagged microsatellite site (STMS) markers. Of these, four populations were on-farm managed, assembled from different niche environments, and one population was conserved ex situ and represented static conservation. The 16 STMS primer pairs fully differentiated the inter- and intrapopulation diversity. A total of 72 alleles were recorded with a mean of 4.5 alleles per locus. Population wise, the total number of alleles ranged from 21 to 41, with maximum number of alleles for population IC 548358 and minimum number of alleles for population IC 100051 representing static conservation. A greater number of alleles specific to populations under farmer management could be recorded. Changes in yield parameters also seemed to be affected under farmer management besides other environmental adaptations for qualitative morphological characters. The marker diversity using STMS primer pairs indicates the genetic differentiation among populations resulting from joint effects of several evolutionary forces operating within the historical and biological context of the crop landrace. The variations in adaptations, on the other hand, indicate the degree to which populations are adapted to their environments and their potential for continued performance or as donors of characters in plant breeding. Both biotic and abiotic aspects of the environment are involved.

Multiplex polymerase chain reaction for simultaneous detection and identification of Bursaphelenchus xylophilus, B. mucronatus and B. fraudulentus – three closely related species within the xylophilus group

Nematology ◽  
2017 ◽  
Vol 19 (9) ◽  
pp. 1107-1116 ◽  
Author(s):  
Anna Filipiak ◽  
Przemysław Wieczorek ◽  
Marek Tomalak
Keyword(s):  
Multiplex Pcr ◽  
Simultaneous Detection ◽  
Morphological Characters ◽  
Bursaphelenchus Xylophilus ◽  
Chain Reaction ◽  
Closely Related Species ◽  
Detection And Identification ◽  
Different Populations ◽  
Polymerase Chain ◽  
Simultaneous Identification

Differentiation between Bursaphelenchus xylophilus and other related, non-pathogenic species can be ambiguous when based exclusively on morphological characters. The morphology of B. mucronatus and B. fraudulentus most closely resembles that of B. xylophilus. Moreover, all of these nematodes are found in both Asia and Europe and can colonise various species of pine. Therefore, for phytosanitary purposes it is necessary to identify the three species precisely and rapidly. We report the results of a multiplex PCR that utilises four primers to identify and discriminate the three Bursaphelenchus species simultaneously. The multiplex PCR yielded DNA fragments of 767, 305 and 132 bp, for B. xylophilus, B. mucronatus and B. fraudulentus, respectively. This primer combination has produced reliable results in multiplex PCR assays with a number of different populations of the listed species, and no cross-reactions were observed with other Bursaphelenchus species. The described approach is simple, reliable and cheaper than other molecular methods presently used for simultaneous identification of the above three species within the xylophilus group.

A revision of the Rhododendron taipaoense complex (subg. Tsutsusi sect. Tsutsusi, Ericaceae), based on observations of morphological characters and seed micromorphology

Phytotaxa ◽  
2013 ◽  
Vol 92 (2) ◽  
pp. 25
Author(s):  
XIAO-FENG JIN ◽  
BING-YANG DING ◽  
YING-YING ZHOU ◽  
SHUI-HU JIN ◽  
WANG-WEI YANG
Keyword(s):  
Morphological Characters ◽  
Principal Coordinate Analysis ◽  
Morphological Data ◽  
Herbarium Specimens ◽  
Leaf Color ◽  
Flower Number ◽  
Seed Shape ◽  
Corolla Length ◽  
Seed Micromorphology ◽  
Different Populations

In this paper, we present a revision of the Rhododenron taipaoense complex, including R. taipaoense and eight other named species, based on literature survey, field collections and observations, inspection of herbarium specimens, statistical analysis of morphological characters, and SEM observation of seed shape and testa. We evaluated all characters that have previously been used to diagnose these species: indumentum of young shoots and abaxial surfaces of leaves; filament dimensions; style base; leaf color, size, and apex shape; flower number per inflorescence; corolla length; and length of the stamen and pistil. Cluster analysis of 146 individuals showed that individuals from different populations are interdigitated, irrespective of traditional taxonomic limits. Analysis of morphological data using principal coordinate analysis (PCoA) likewise shows a continual gradation between populations, rather than disjunctures between named species. Consequently, only one species is recognized in the present paper, and R. apricum, R. falcinellum (R. apricum var. falcinellum), R. florulentum, R. hepticum, R. piceum, R. rufulum, R. spadiceum, and R. rufoindumentum (nom. nud.) are all reduced to synonyms of R. taipaoense.

Taxonomy and variability of three Texigryphaea (Bivalvia) species from their Lower Cretaceous (Albian) type localities in New Mexico and Oklahoma

1989 ◽  
Vol 63 (4) ◽  
pp. 454-483 ◽  
Author(s):  
Barry S. Kues
Keyword(s):  
New Mexico ◽  
Local Variation ◽  
Morphological Characters ◽  
The Other ◽  
Ontogenetic Changes ◽  
Free Living ◽  
Marine Communities ◽  
West Texas ◽  
Turbulence Length ◽  
Group Species

The benthic, free-living oyster Texigryphaea was the dominant constituent of many late Albian marine communities in the Texas and southern Western Interior regions. Large topotypic assemblages of three common lower–middle Washita Group species (T. navia and T. pitcheri in Oklahoma and T. tucumcarii in New Mexico) each display considerable morphological variation in valve shape and the proportions and expression of various features. Variation within an assemblage is partly due to ontogenetic changes but is mainly ecophenotypic, with local variation in nature of substrate, water turbulence, length of attachment time, and other factors influencing the final morphology of the mature shell. The T. navia assemblage is distinct in several important morphological characters from the other species, and the differences become more pronounced with growth. Texigryphaea navia appears to have been adapted to relatively firm substrates in moderately agitated conditions, in contrast to the other species, which occupied softer substrates in quieter environments. The essentially contemporaneous T. pitcheri and T. tucumcarii assemblages display much overlap in all measured dimensions of the left valve and in the range of intergrading morphs that compose each assemblage. Accordingly, T. tucumcarii is considered a synonym of T. pitcheri, representing populations of that species that lived in the West Texas-New Mexico area and developed only minor differences from the eastern populations. Within the T. navia topotypic assemblage are specimens intermediate between T. navia and T. pitcheri, and the eastern and western T. pitcheri assemblages contain forms apparently transitional to two other species, T. washitaensis and T. belviderensis. Ecophenotypic variation in the T. pitcheri assemblages appears to be greater than that in European Jurassic Gryphaea species and mirrors to some extent phyletic variation in European Jurassic Gryphaea lineages.

scholarly journals Morphological variability of acorns and its taxonomic significance in Quercus. from Turkey

2015 ◽  
Vol 43 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Y Bakis ◽  
MT Babaç
Keyword(s):  
Principal Component Analysis ◽  
Morphological Variability ◽  
Morphological Characteristics ◽  
Principal Component ◽  
Component Analysis ◽  
Morphological Characters ◽  
Taxonomic Significance ◽  
Morphological Variations ◽  
Quercus Species ◽  
Different Populations

Morphological variations of acorn among and within the groups of Quercus species were studied. A total of 617 acorns belonging to 14 species representing all 3 sections of Quercus L. (Fagaceae) in Turkey were examined in this study. Specimens were collected from 47 different populations over both Anatolian and Thrace part of Turkey. Principal component analysis was used to analyze the morphological characteristics of acorns. Results obtained from this study demonstrate the use of morphological characters in differentiating the taxa of Quercus and Cerris sections studied. Another important finding is the introgression among the acorns of species within Quercus section DOI: http://dx.doi.org/10.3329/bjb.v43i3.21601 Bangladesh J. Bot. 43(3): 293-299, 2014 (December)

The Incidence of Nematodes in the Fillets of Small God from Lockeport, Nova Scotia, and the Southwestern Gulf of St. Lawrence

1959 ◽  
Vol 16 (2) ◽  
pp. 213-221 ◽  
Author(s):  
D. M. Scott ◽  
W. R. Martin
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Geographic Variation ◽  
Atlantic Cod ◽  
Age Groups ◽  
Local Variation ◽  
Progressive Increase ◽  
Magdalen Islands

The incidence of nematodes in fillets of Atlantic cod (Gadus callarias) was determined in 1957 in four areas within 10 miles of Lockeport, N.S., and in six areas in the southwestern Gulf of St. Lawrence. About 1,500 cod, mostly between 1 and 6 years of age, were examined. All nematodes examined (517) were larvae. About 97% belonged to the genus Porrocaecum; the remainder appeared to belong to the genus Anisakis. In all areas there was a progressive increase in incidence with increasing age of cod. In age-groups IV and V usually more than 70% of the cod were infected. Considerable local variation in incidence was observed in the Lockeport region. Cod were more heavily infected in inshore than in offshore waters. The samples from the Gulf of St. Lawrence showed less geographic variation in incidence than the Lockeport samples. The incidence in cod from the Magdalen Islands was noticeably lower than that in cod from the New Brunswick shore. Cod in the Gulf of St. Lawrence were infected to about the same extent as those from the offshore areas near Lockeport. The relation between local variations in incidence and the distribution of seals is briefly discussed.

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