Species limits and hypotheses of hybridization of Solanum berthaultii Hawkes and S. tarijense Hawkes: morphological data

Taxon ◽  
1992 ◽  
Vol 41 (4) ◽  
pp. 685-700 ◽  
Author(s):  
David M. Spooner ◽  
Ronald G. Berg
Keyword(s):  
Morphological Data ◽  
Solanum Berthaultii ◽  
Species Limits

Species Limits Based on mtDNA and Morphological Data in the Polytypic Species Plestiodon brevirostris (Squamata: Scincidae)

2011 ◽  
Vol 25 (1) ◽  
pp. 25-51 ◽  
Author(s):  
Manuel Feria-Ortiz ◽  
Norma L Manríquez-Morán ◽  
Adrián Nieto-Montes de Oca
Keyword(s):  
Morphological Data ◽  
Species Limits

scholarly journals Phylogeny and Biogeography of the Amazonian Pachyptera (Bignonieae, Bignoniaceae)

2020 ◽  
Vol 45 (2) ◽  
pp. 361-374
Author(s):  
Jessica Nayara Carvalho Francisco ◽  
Lúcia G. Lohmann
Keyword(s):  
Species Complex ◽  
Middle Eocene ◽  
Morphological Data ◽  
Species Limits ◽  
Test Species ◽  
Multispecies Coalescent ◽  
Biogeographic History ◽  
Coalescent Approach ◽  
History Of ◽  
Migration Pathways

Abstract—The Amazon houses a large proportion of the overall biodiversity currently found on Earth. Despite that, our knowledge of Amazonian biodiversity is still limited. In this study, we reconstruct the phylogeny of Pachyptera (Bignoniaceae), a genus of neotropical lianas that is centered in the Amazon. We then use this phylogenetic framework to re-evaluate species limits and study the biogeographic history of the genus. We sampled three molecular markers (i.e. ndhF, rpl32-trnL, and PepC) and 51 individuals representing the breadth of morphological variation and geographic distribution of all species recognized in the genus. We used this information to reconstruct phylogenetic relationships among individuals of Pachyptera using Bayesian and maximum likelihood approaches. The resulting molecular phylogeny was used as a basis to test species limits within the P. kerere species complex using a cpDNA coalescent approach (GMYC). GMYC identified five potential species within the P. kerere species complex that were subsequently evaluated in the light of morphology. Morphological data supported the recognition of four of the five potential species suggested by GMYC, all of which were also supported by a multispecies coalescent model in a Bayesian framework. The phylogeny of Pachyptera was time-calibrated and used to reconstruct the biogeographical history of the genus. We identified historically important migration pathways using our comprehensive cpDNA dataset and a Bayesian stochastic search variable selection (BSSVS) framework. Our results indicate that the genus originated in lowland Amazonia during the Middle Eocene, and subsequently occupied Central America and the Andes. Most of the diversification of Pachyptera occurred in the Miocene, a period of intense perturbations in South America.

Species limits in Carpha (Schoeneae, Cyperaceae) based on phenetic analyses

2006 ◽  
Vol 19 (5) ◽  
pp. 437 ◽  
Author(s):  
Xiufu Zhang ◽  
Karen L. Wilson ◽  
Jeremy J. Bruhl
Keyword(s):  
Morphological Data ◽  
Species Limits ◽  
Number Of Species ◽  
Taxonomic History ◽  
History Of

We review the taxonomic history of Carpha. Recent estimates of the number of species in Carpha have varied from 4 to 15. The generic limits of Carpha and some species limits within Carpha have been uncertain. This study tests the limits of species in Carpha sensu lato by phenetic analyses of morphological data and identifies 16 species. Three of them (Carpha cf. bracteosa C.B.Clarke, C. discolor ms and C. ulugurensis ms) are new; the taxonomic ranks of C. angustissima Cherm., C. capitellata (Nees) Boeck. var. bracteosa (C.B.Clarke) Kük., C. nivicola F.Muell. and C. schoenoides Banks et Sol. ex Hook.f. are clarified; C. perrieri Cherm. is synonymised with C. capitellata (Nees) Boeck.; the definitions of C. schlechteri C.B.Clarke and C. glomerata (Thunb.) Nees are amended.

scholarly journals Atlantean Evolution in Darwin’s Finches—Issues and Perspectives in Species Delimitation using Phenotypic Data

2017 ◽  
Author(s):  
Carlos Daniel Cadena ◽  
Iván Jiménez ◽  
Felipe Zapata
Keyword(s):  
Mixture Models ◽  
Species Delimitation ◽  
Morphological Data ◽  
Phenotypic Traits ◽  
Normal Mixture ◽  
Species Limits ◽  
Phenotypic Data ◽  
Normal Mixture Models ◽  
Multiple Species ◽  
Analytical Approaches

AbstractProgress in the development and use of methods for species delimitation employing phenotypic data lags behind conceptual and practical advances in molecular genetic approaches. The basic evolutionary model underlying the use of phenotypic data to delimit species assumes random mating and quantitative polygenic traits, so that phenotypic distributions within a species should be approximately normal for individuals of the same sex and age. Accordingly, two or more distinct normal distributions of phenotypic traits suggest the existence of multiple species. In light of this model, we show that analytical approaches employed in taxonomic studies using phenotypic data are often compromised by three issues: (1) reliance on graphical analyses of phenotypic space that do not consider the frequency of phenotypes; (2)exclusion of characters potentially important for species delimitation following reduction of data dimensionality; and (3) use of measures of central tendencies to evaluate phenotypic distinctiveness. We outline approaches to overcome these issues based on statistical developments related to normal mixture models and illustrate them empirically with a reanalysis of morphological data recently used to claim that there are no morphologically distinct species of Darwin’s ground-finches (Geospiza). We found negligible support for this claim relative to taxonomic hypotheses recognizing multiple species. Although species limits among ground-finches merit further assessments using additional sources of information, our results bear implications for other areas of inquiry including speciation research: because ground-finches have likely speciated and are not trapped in a process of “Sisyphean” evolution as recently argued, they remain useful models to understand the evolutionary forces involved in speciation. Our work underscores the importance of statistical approaches grounded on appropriate evolutionary models for species delimitation. Approaches allowing one to fit normal mixture models withouta prioriinformation about species limits offer new perspectives in the kind of inferences available to systematists, with significant repercusions on ideas about the structure of biological biodiversity. [morphology; normal mixture model; phenotype; principal components analysis; species limits; variable selection.]

Evaluating species limits and hybridization in the Carex complanata complex using morphology, amplified fragment length polymorphisms, and restriction fragment analysisThis paper is one of a selection of papers published in the Special Issue on Systematics Research.

Botany ◽  
2008 ◽  
Vol 86 (8) ◽  
pp. 809-826 ◽  
Author(s):  
Tyler W. Smith ◽  
Marcia J. Waterway
Keyword(s):  
Fragment Length ◽  
Restriction Site ◽  
Morphological Data ◽  
Species Limits ◽  
Aflp Data ◽  
Subtle Difference ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
Selection Of ◽  
Sterile Hybrids

We used a combination of morphology, amplified fragment length polymorphisms (AFLP), and restriction-site data from 252 individuals from 51 populations to investigate species limits and hybridization in the Carex complanata complex. Principal coordinate analysis of the morphological data shows clear separation of entities corresponding to Carex bushii Mackenzie and Carex caroliniana Schwein. However, only leaf indumentum reliably distinguished between Carex hirsutella Mackenzie and Carex complanata Torr. & Hook. Despite this very subtle difference, AFLP data reveal very clear genetic separation of these two taxa. Contrary to the assertions of previous authors, we found no evidence of introgression among C. complanata, C. caroliniana, and C. bushii. Relatively high genetic variation within C. hirsutella may be an indication of gene-flow between this species and one or more other species, but further work is necessary to clarify this issue. We document six previously undescribed sterile or nearly sterile hybrids involving the species in this complex.

Scanning electron microscopy of freeze-fractured prescapular lymph node of caprine

1984 ◽  
Vol 42 ◽  
pp. 244-245
Author(s):  
O. Faroon ◽  
F. Al-Bagdadi ◽  
T. G. Snider ◽  
C. Titkemeyer
Keyword(s):  
Lymph Node ◽  
Lymph Nodes ◽  
Lymphatic System ◽  
Three Dimensional ◽  
Meat Products ◽  
The Body ◽  
Morphological Data ◽  
The World ◽  
Cellular Constituent ◽  
Scanning Electron

The lymphatic system is very important in the immunological activities of the body. Clinicians confirm the diagnosis of infectious diseases by palpating the involved cutaneous lymph node for changes in size, heat, and consistency. Clinical pathologists diagnose systemic diseases through biopsies of superficial lymph nodes. In many parts of the world the goat is considered as an important source of milk and meat products.The lymphatic system has been studied extensively. These studies lack precise information on the natural morphology of the lymph nodes and their vascular and cellular constituent. This is due to using improper technique for such studies. A few studies used the SEM, conducted by cutting the lymph node with a blade. The morphological data collected by this method are artificial and do not reflect the normal three dimensional surface of the examined area of the lymph node. SEM has been used to study the lymph vessels and lymph nodes of different animals. No information on the cutaneous lymph nodes of the goat has ever been collected using the scanning electron microscope.

Control of Secretory Production in the Isopod Hepatopancreas

1972 ◽  
Vol 30 ◽  
pp. 166-167
Author(s):  
John W. Roberts ◽  
E. R. Witkus
Keyword(s):  
B Cells ◽  
Morphological Data ◽  
Secretory Product ◽  
Secretory Function ◽  
Secretory Material ◽  
Blind Ending ◽  
Secretory Production ◽  
Regenerative Cells ◽  
Immature Cells ◽  
And Storage

The isopod hepatopancreas, as exemplified by Oniscus ascellus. is comprised of four blind-ending diverticula. The regenerative cells at the tip of each diverticula differentiate into either club-shaped B-cells, which serve a secretory function, or into conoid S-cells, which serve in the absorption and storage of nutrients.The glandular B-cells begin producing secretory material with the development of rough endoplasmic reticulum during their process of maturation from the undifferentiated regenerative cells. Cytochemical and morphological data indicate that the hepatopancreas sequentially produces two types of secretory material within the large club-shaped cells. The production of the carbohydrate-like secretory product in immature cells seems to be phased out as the production of the osmiophilic secretion was phased in as the cell matured.

Joseph Sidebotham: vicissitudes of a Victorian collector

2015 ◽  
Vol 42 (2) ◽  
pp. 197-210 ◽  
Author(s):  
Laurence M. Cook
Keyword(s):  
Natural History ◽  
Species Limits ◽  
Clear Cut ◽  
Natural History Collections ◽  
As Species ◽  
Scientific World

Joseph Sidebotham (1824–1885) was a Manchester cotton baron whose natural history collections are now in the Manchester Museum. In addition to collecting he suggested a method for identifying and classifying Lepidoptera and investigated variation within species as well as species limits. With three close collaborators, he is credited with discovering many species new to Britain in both Lepidoptera and Coleoptera. A suspicion of fraud attaches to these claims. The evidence is not clear-cut in the Lepidoptera, but a possible reason is suggested why Sidebotham, as an amateur in the increasingly professional scientific world, might have engaged in deceit.

Silicon Surface Chemical Treatments in Oxide/Nitride Dielectric Stack Properties

2002 ◽  
Vol 716 ◽  
Author(s):  
D. Jacques ◽  
S. Petitdidier ◽  
J.L. Regolini ◽  
K. Barla
Keyword(s):  
Oxygen Content ◽  
Oxide Thickness ◽  
Morphological Data ◽  
Electrical Characteristics ◽  
Electrical Measurements ◽  
Chemical Cleaning ◽  
Force Microscopy ◽  
Chemical Treatments ◽  
Atomic Force ◽  
Interfacial Oxygen

AbstractOxide/Nitride dielectric stack is widely used as the standard dielectric for DRAM capacitors. The influence of the chemical cleaning prior to the stack formation has been studied in this work. As a result, morphological data such as stack surface roughness (Atomic Force Microscopy) and silicon nitride (SiN) incubation time for growth are comparable for all the studied cases on <Si>. However, Tof-SIMS exhibits different oxygen content at the Si/stack interface following the different chemical treatments. Electrical measurements show comparable C-V and I-V results, for the same Equivalent Oxide Thickness (same capacitance at strong accumulation i.e.-3V) while the different studied interfaces bring different interface states density with lower values for higher interfacial oxygen content. For DRAM applications, a clear improvement in electrical characteristics is obtained under low interfacial oxygen content conditions. Results are compared in embedded-DRAM cells for which we developed an industrially compatible dielectric deposition sequence to obtain minimum leakage current with maximum specific capacitance and no particular linking constraints.

Sign in / Sign up

Export Citation Format

Share Document