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1.
Proc Natl Acad Sci U S A ; 120(45): e2306899120, 2023 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-37903262

RESUMEN

Taxonomic data are a scientific common. Unlike nomenclature, which has strong governance institutions, there are currently no generally accepted governance institutions for the compilation of taxonomic data into an accepted global list. This gap results in challenges for conservation, ecological research, policymaking, international trade, and other areas of scientific and societal importance. Consensus on a global list and its management requires effective governance and standards, including agreed mechanisms for choosing among competing taxonomies and partial lists. However, governance frameworks are currently lacking, and a call for governance in 2017 generated critical responses. Any governance system to which compliance is voluntary requires a high level of legitimacy and credibility among those by and for whom it is created. Legitimacy and credibility, in turn, require adequate and credible consultation. Here, we report on the results of a global survey of taxonomists, scientists from other disciplines, and users of taxonomy designed to assess views and test ideas for a new system of taxonomic list governance. We found a surprisingly high degree of agreement on the need for a global list of accepted species and their names, and consistent views on what such a list should provide to users and how it should be governed. The survey suggests that consensus on a mechanism to create, manage, and govern a single widely accepted list of all the world's species is achievable. This finding was unexpected given past controversies about the merits of list governance.


Asunto(s)
Comercio , Médicos , Humanos , Internacionalidad
2.
Nat Ecol Evol ; 7(8): 1170, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37337003

Asunto(s)
Epónimos
3.
Front Plant Sci ; 14: 1063174, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36959945

RESUMEN

Sapindales is an angiosperm order of high economic and ecological value comprising nine families, c. 479 genera, and c. 6570 species. However, family and subfamily relationships in Sapindales remain unclear, making reconstruction of the order's spatio-temporal and morphological evolution difficult. In this study, we used Angiosperms353 target capture data to generate the most densely sampled phylogenetic trees of Sapindales to date, with 448 samples and c. 85% of genera represented. The percentage of paralogous loci and allele divergence was characterized across the phylogeny, which was time-calibrated using 29 rigorously assessed fossil calibrations. All families were supported as monophyletic. Two core family clades subdivide the order, the first comprising Kirkiaceae, Burseraceae, and Anacardiaceae, the second comprising Simaroubaceae, Meliaceae, and Rutaceae. Kirkiaceae is sister to Burseraceae and Anacardiaceae, and, contrary to current understanding, Simaroubaceae is sister to Meliaceae and Rutaceae. Sapindaceae is placed with Nitrariaceae and Biebersteiniaceae as sister to the core Sapindales families, but the relationships between these families remain unclear, likely due to their rapid and ancient diversification. Sapindales families emerged in rapid succession, coincident with the climatic change of the Mid-Cretaceous Hothouse event. Subfamily and tribal relationships within the major families need revision, particularly in Sapindaceae, Rutaceae and Meliaceae. Much of the difficulty in reconstructing relationships at this level may be caused by the prevalence of paralogous loci, particularly in Meliaceae and Rutaceae, that are likely indicative of ancient gene duplication events such as hybridization and polyploidization playing a role in the evolutionary history of these families. This study provides key insights into factors that may affect phylogenetic reconstructions in Sapindales across multiple scales, and provides a state-of-the-art phylogenetic framework for further research.

4.
Am J Bot ; 109(2): 291-308, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34671970

RESUMEN

PREMISE: Continental-scale disjunctions and associated drivers are core research interests in biogeographic studies. Here, we selected a species-rich Australian plant genus (Calytrix; Myrtaceae) as a case study to investigate these patterns. Species of this endemic Australian starflower genus have a disjunct distribution across the mesic fringes of the continent and are largely absent from the arid center. METHODS: We used high-throughput sequencing to generate unprecedented resolution and near complete species-level nuclear and plastid phylogenies for Calytrix. BioGeoBEARS and biogeographic stochastic mapping were used to infer ancestral areas, the relative contributions of vicariance and dispersal events, and directionality of dispersal. RESULTS: Present-day disjunctions in Calytrix are explained by a combination of scenarios: (1) retreat of multiple lineages from the continental center to the more mesic fringes as Australia became progressively more arid, with subsequent extinction in the center as well as (2) origination of ancestral lineages in southwestern Australia (SWA) for species-rich clades. The SWA biodiversity hotspot is a major diversification center and the most common source area of dispersals, with multiple lineages originating in SWA and subsequently spreading to the adjacent arid Eremaean region. CONCLUSIONS: Our results suggest that major extinction, as a result of cooling and drying of the Australian continent in the Eocene-Miocene, shaped the present-day biogeography of Calytrix. We hypothesize that this peripheral vicariance pattern, which is similar to the African Rand flora, may explain the disjunctions of many other Australian plant groups. Further studies with densely sampled phylogenies are required to test this hypothesis.


Asunto(s)
Biodiversidad , Myrtaceae , Australia , Teorema de Bayes , Filogenia , Filogeografía , Plastidios
5.
Mol Phylogenet Evol ; 158: 107085, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33540078

RESUMEN

AIM: Gondwanan biogeographic patterns include a combination of old vicariance events following the breakup of the supercontinent, and more recent long-distance dispersals across the southern landmasses. Floristic relationships between Australia and New Zealand have mostly been attributed to recent dispersal events rather than vicariance. We assessed the biogeographic history of Pomaderris (Rhamnaceae), which occurs in both Australia and New Zealand, by constructing a time-calibrated molecular phylogeny to infer (1) phylogenetic relationships and (2) the relative contributions of vicariance and dispersal events in the biogeographic history of the genus. LOCATION: Australia and New Zealand. METHODS: Using hybrid capture and high throughput sequencing, we generated nuclear and plastid data sets to estimate phylogenetic relationships and fossil calibrated divergence time estimates for Pomaderris. BioGeoBEARS and biogeographical stochastic mapping (BSM) were used to assess the ancestral area of the genus and the relative contributions of vicariance vs dispersal, and the directionality of dispersal events. RESULTS: Our analyses indicate that Pomaderris originated in the Oligocene and had a widespread Australian distribution. Vicariance of western and eastern Australian clades coincides with the uplift of the Nullarbor Plain c. 14 Ma, followed by subsequent in-situ and within-biome diversification with little exchange across regions. A rapid radiation of southeastern Australian taxa beginning c. 10 Ma was the source for at least six independent long-distance dispersal events to New Zealand during the Pliocene-Pleistocene. MAIN CONCLUSIONS: Our study demonstrates the importance of dispersal in explaining not only the current cross-Tasman distributions of Pomaderris, but for the New Zealand flora more broadly. The pattern of multiple independent long-distance dispersal events for Pomaderris, without significant radiation within New Zealand, is congruent with other lowland plant groups, suggesting that this biome has a different evolutionary history compared with the younger alpine flora of New Zealand, which exhibits extensive radiations often following single long distance dispersal events.


Asunto(s)
Rhamnaceae/clasificación , Australia , Núcleo Celular/genética , ADN de Plantas/química , ADN de Plantas/metabolismo , Fósiles/historia , Historia Antigua , Nueva Zelanda , Filogenia , Filogeografía , Plastidios/genética , Rhamnaceae/genética , Análisis de Secuencia de ADN
6.
PLoS Biol ; 18(7): e3000736, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32634138

RESUMEN

Lists of species underpin many fields of human endeavour, but there are currently no universally accepted principles for deciding which biological species should be accepted when there are alternative taxonomic treatments (and, by extension, which scientific names should be applied to those species). As improvements in information technology make it easier to communicate, access, and aggregate biodiversity information, there is a need for a framework that helps taxonomists and the users of taxonomy decide which taxa and names should be used by society whilst continuing to encourage taxonomic research that leads to new species discoveries, new knowledge of species relationships, and the refinement of existing species concepts. Here, we present 10 principles that can underpin such a governance framework, namely (i) the species list must be based on science and free from nontaxonomic considerations and interference, (ii) governance of the species list must aim for community support and use, (iii) all decisions about list composition must be transparent, (iv) the governance of validated lists of species is separate from the governance of the names of taxa, (v) governance of lists of accepted species must not constrain academic freedom, (vi) the set of criteria considered sufficient to recognise species boundaries may appropriately vary between different taxonomic groups but should be consistent when possible, (vii) a global list must balance conflicting needs for currency and stability by having archived versions, (viii) contributors need appropriate recognition, (ix) list content should be traceable, and (x) a global listing process needs both to encompass global diversity and to accommodate local knowledge of that diversity. We conclude by outlining issues that must be resolved if such a system of taxonomic list governance and a unified list of accepted scientific names generated are to be universally adopted.


Asunto(s)
Clasificación , Biodiversidad , Toma de Decisiones , Conocimiento , Reproducibilidad de los Resultados , Especificidad de la Especie
7.
Biodivers Data J ; 8: e51094, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32508510

RESUMEN

Background The Sunda-Sahul Convergence Zone, defined here as the area comprising Australia, New Guinea, and Southeast Asia (Indonesia to Myanmar), straddles the Sunda and Sahul continental shelves and is one of the most biogeographically famous and important regions in the world. Floristically, it is thought to harbour a large amount of the world's diversity. Despite the importance of the area, a checklist of the flora has never before been published. Here we present the first working checklist of vascular plants for the Sunda-Sahul Convergence Zone. The list was compiled from 24 flora volumes, online databases and unpublished plot data. Taxonomic nomenclature was updated, and each species was coded into nested biogeographic regions. The list includes 60,415 species in 5,135 genera and 363 families of vascular plants. New information This is the first species-level checklist of the region and presents an updated census of the region's floristic biodiversity. The checklist confirms that species richness of the SSCZ is comparable to that of the Neotropics, and highlights areas in need of further documentation and taxonomic work. This checklist provides a novel dataset for studying floristic ecology and evolution in this biogeographically important region of very high global biodiversity.

8.
Proc Biol Sci ; 287(1919): 20192546, 2020 01 29.
Artículo en Inglés | MEDLINE | ID: mdl-31964242

RESUMEN

The diversification dynamics of the Australian temperate flora remains poorly understood. Here, we investigate whether differences in plant richness in the southwest Australian (SWA) biodiversity hotspot and southeast Australian (SEA) regions of the Australian continent can be attributed to higher net diversification, more time for species accumulation, or both. We assembled dated molecular phylogenies for the 21 most species-rich flowering plant families found across mesic temperate Australia, encompassing both SWA and SEA regions, and applied a series of diversification models to investigate responses across different groups and timescales. We show that the high richness in SWA can be attributed to a higher net rate of lineage diversification and more time for species accumulation. Different pulses of diversification were retrieved in each region. A decrease in diversification rate across major flowering plant lineages at the Eocene-Oligocene boundary (ca 34 Ma) was witnessed in SEA but not in SWA. Our study demonstrates the importance of historical diversification pulses and differential responses to global events as drivers of present-day diversity. More broadly, we show that diversity within the SWA biodiversity hotspot is not only the result of recent radiations, but also reflects older events over the history of this planet.


Asunto(s)
Biodiversidad , Magnoliopsida , Australia , Evolución Biológica , Extinción Biológica , Especiación Genética , Filogenia
9.
Plant Methods ; 16: 1, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31911810

RESUMEN

BACKGROUND: Herbaria are valuable sources of extensive curated plant material that are now accessible to genetic studies because of advances in high-throughput, next-generation sequencing methods. As an applied assessment of large-scale recovery of plastid and ribosomal genome sequences from herbarium material for plant identification and phylogenomics, we sequenced 672 samples covering 21 families, 142 genera and 530 named and proposed named species. We explored the impact of parameters such as sample age, DNA concentration and quality, read depth and fragment length on plastid assembly error. We also tested the efficacy of DNA sequence information for identifying plant samples using 45 specimens recently collected in the Pilbara. RESULTS: Genome skimming was effective at producing genomic information at large scale. Substantial sequence information on the chloroplast genome was obtained from 96.1% of samples, and complete or near-complete sequences of the nuclear ribosomal RNA gene repeat were obtained from 93.3% of samples. We were able to extract sequences for the core DNA barcode regions rbcL and matK from 96 to 93.3% of samples, respectively. Read quality and DNA fragment length had significant effects on sequencing outcomes and error correction of reads proved essential. Assembly problems were specific to certain taxa with low GC and high repeat content (Goodenia, Scaevola, Cyperus, Bulbostylis, Fimbristylis) suggesting biological rather than technical explanations. The structure of related genomes was needed to guide the assembly of repeats that exceeded the read length. DNA-based matching proved highly effective and showed that the efficacy for species identification declined in the order cpDNA >> rDNA > matK >> rbcL. CONCLUSIONS: We showed that a large-scale approach to genome sequencing using herbarium specimens produces high-quality complete cpDNA and rDNA sequences as a source of data for DNA barcoding and phylogenomics.

10.
AoB Plants ; 11(2): plz017, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31037212

RESUMEN

The Australian arid zone (AAZ) has undergone aridification and the formation of vast sandy deserts since the mid-Miocene. Studies on AAZ organisms, particularly animals, have shown patterns of mesic ancestry, persistence in rocky refugia and range expansions in arid lineages. There has been limited molecular investigation of plants in the AAZ, particularly of taxa that arrived in Australia after the onset of aridification. Here we investigate populations of the widespread AAZ grass Triodia basedowii to determine whether there is evidence for a recent range expansion, and if so, its source and direction. We also undertake a dating analysis for the species complex to which T. basedowii belongs, in order to place its diversification in relation to changes in AAZ climate and landscapes. We analyse a genomic single nucleotide polymorphism data set from 17 populations of T. basedowii in a recently developed approach for detecting the signal and likely origin of a range expansion. We also use alignments from existing and newly sequenced plastomes from across Poaceae for analysis in BEAST to construct fossil-calibrated phylogenies. Across a range of sampling parameters and outgroups, we detected a consistent signal of westward expansion for T. basedowii, originating in central or eastern Australia. Divergence time estimation indicates that Triodia began to diversify in the late Miocene (crown 7.0-8.8 million years (Ma)), and the T. basedowii complex began to radiate during the Pleistocene (crown 1.4-2.0 Ma). This evidence for range expansion in an arid-adapted plant is consistent with similar patterns in AAZ animals and likely reflects a general response to the opening of new habitat during aridification. Radiation of the T. basedowii complex through the Pleistocene has been associated with preferences for different substrates, providing an explanation why only one lineage is widespread across sandy deserts.

11.
Am J Bot ; 105(6): 1021-1034, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29995314

RESUMEN

PREMISE OF THE STUDY: Calandrinia are small, succulent herbs that vary broadly in habitat, morphology, life history, and photosynthetic metabolism. The lineage is placed within the Montiaceae, which in turn is sister to the rest of the Portulacineae (Caryophyllales). Calandrinia occupy two distinct biogeographic regions, one in the Americas (~14 species), and one in Australia (~74 species). Past analyses of the Montiaceae present conflicting hypotheses for the phylogenetic placement and monophyly of Calandrinia, and to date, there has been no molecular phylogenetic analysis of the Australian species. METHODS: Using a targeted gene enrichment approach, we sequenced 297 loci from multiple gene families across the Montiaceae, including all named and 16 putative new species of Australian Calandrinia, and the enigmatic monotypic genus Rumicastrum. KEY RESULTS: All data sets and analyses reject the monophyly of Calandrinia, with Australian and New World Calandrinia each comprising distinct and well-supported clades, and Rumicastrum nested within Australian Calandrinia. We provide the first well-supported phylogeny for Australian Calandrinia, which includes all named species and several phrase-named taxa. CONCLUSIONS: This study brings much needed clarity to relationships within Montiaceae and confirms that New World and Australian Calandrinia do not form a clade. Australian Calandrinia is a longtime resident of the continent, having diverged from its sister lineage ~30 Ma, concurrent with separation of Australia from Antarctica. Most diversification occurred during the middle Miocene, with lowered speciation and/or higher extinction rates coincident with the establishment of severe aridity by the late Miocene.


Asunto(s)
Caryophyllales/genética , Filogenia , Australia , Filogeografía
12.
PLoS One ; 12(1): e0171053, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28135342

RESUMEN

Next-generation sequencing is becoming increasingly accessible to researchers asking biosystematic questions, but current best practice in both choosing a specific approach and effectively analysing the resulting data set is still being explored. We present a case study for the use of genotyping-by-sequencing (GBS) to resolve relationships in a species complex of Australian arid and semi-arid grasses (Triodia R.Br.), highlighting our solutions to methodological challenges in the use of GBS data. We merged overlapping paired-end reads then optimised locus assembly in the program PyRAD to generate GBS data sets for phylogenetic and distance-based analyses. In addition to traditional concatenation analyses in RAxML, we also demonstrate the novel use of summary species tree analyses (taking gene trees as input) with GBS loci. We found that while species tree analyses were relatively robust to variation in PyRAD assembly parameters, our RAxML analyses resulted in well-supported but conflicting topologies under different assembly settings. Despite this conflict, multiple clades in the complex were consistently supported as distinct across analyses. Our GBS data assembly and analyses improve the resolution of taxa and phylogenetic relationships in the Triodia basedowii complex compared to our previous study based on Sanger sequencing of nuclear (ITS/ETS) and chloroplast (rps16-trnK spacer) markers. The genomic results also partly support previous evidence for hybridization between species in the complex. Our methodological insights for analysing GBS data will assist researchers using similar data to resolve phylogenetic relationships within species complexes.


Asunto(s)
Técnicas de Genotipaje/métodos , Filogenia , Poaceae/genética , Análisis de Secuencia de ADN/métodos , Análisis por Conglomerados , Biología Computacional , ADN Intergénico/genética , Bases de Datos de Ácidos Nucleicos , Sitios Genéticos , Geografía , Funciones de Verosimilitud , Ploidias , Polimorfismo de Nucleótido Simple/genética , Programas Informáticos , Especificidad de la Especie
13.
Mol Phylogenet Evol ; 101: 142-162, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27179699

RESUMEN

The vast Australian arid zone formed over the last 15million years, and gradual aridification as well as more extreme Pliocene and Pleistocene climate shifts have impacted the evolution of its biota. Understanding the evolutionary history of groups of organisms or regional biotas such as the Australian arid biota requires clear delimitation of the units of biodiversity (taxa). Here we integrate evidence from nuclear (ETS and ITS) and chloroplast (rps16-trnK spacer) regions and morphology to clarify taxonomic boundaries in a species complex of Australian hummock grasses (Triodia) to better understand the evolution of Australian arid zone plants and to evaluate congruence in distribution patterns with co-occurring organisms. We find evidence for multiple new taxa in the T. basedowii species complex, but also incongruence between data sets and indications of hybridization that complicate delimitation. We find that the T. basedowii complex has high lineage diversity and endemism in the biologically important Pilbara region of Western Australia, consistent with the region acting as a refugium. Taxa show strong geographic structure in the Pilbara, congruent with recent work on co-occurring animals and suggesting common evolutionary drivers across the biota. Our findings confirm recognition of the Pilbara as an important centre of biodiversity in the Australian arid zone, and provide a basis for future taxonomic revision of the T. basedowii complex and more detailed study of its evolutionary history and that of arid Australia.


Asunto(s)
Poaceae/clasificación , Animales , Australia , Biodiversidad , Evolución Biológica , Cloroplastos/genética , ADN de Plantas/química , ADN de Plantas/aislamiento & purificación , ADN de Plantas/metabolismo , Filogenia , Hojas de la Planta/genética , Poaceae/genética , Análisis de Secuencia de ADN
14.
Biodivers Data J ; (2): e1558, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25425933

RESUMEN

The amount of plant biodiversity data available via the web has exploded in the last decade, but making these data available requires a considerable investment of time and work, both vital considerations for organizations and institutions looking to validate the impact factors of these online works. Here we used Google Analytics (GA), to measure the value of this digital presence. In this paper we examine usage trends using 15 different GA accounts, spread across 451 institutions or botanical projects that comprise over five percent of the world's herbaria. They were studied at both one year and total years. User data from the sample reveal: 1) over 17 million web sessions, 2) on five primary operating systems, 3) search and direct traffic dominates with minimal impact from social media, 4) mobile and new device types have doubled each year for the past three years, 5) and web browsers, the tools we use to interact with the web, are changing. Server-side analytics differ from site to site making the comparison of their data sets difficult. However, use of Google Analytics erases the reporting heterogeneity of unique server-side analytics, as they can now be examined with a standard that provides a clarity for data-driven decisions. The knowledge gained here empowers any collection-based environment regardless of size, with metrics about usability, design, and possible directions for future development.

15.
Can J Diet Pract Res ; 68(2): 67-72, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17553191

RESUMEN

PURPOSE: How Canadian dietitians define and use non-dieting and size acceptance approaches (SAAs) in the context of weight management was explored. METHODS: Fifteen focus groups with 104 dietitians were conducted in seven Canadian cities. Questions were designed to explore participants' understanding and use of non-dieting and SAAs, including counselling goals, techniques, and outcome measures. Sessions were tape-recorded, transcribed verbatim, coded, and analyzed using qualitative methods. RESULTS: Participants generally agreed that non-dieting involves promoting healthy lifestyles and avoiding restrictive diets. Participants also agreed that size acceptance means accepting all body shapes and sizes and promoting comfort with one's body. Many dietitians said they use size acceptance only with appropriate clients, most often with those who are lighter or without other health risks. Others said that size acceptance, by definition, is appropriate for everyone. Opinions varied about the appropriateness of teaching portion sizes or using meal plans, and whether weight loss could be a goal of non-dieting and SAAs. CONCLUSIONS: Views on the usefulness of non-dieting and size acceptance strategies in weight management counselling were related, at least partially, to the different understanding that dietitians had of these approaches. Terminology needs to be clarified when we speak about non-dieting and SAAs. The varied understanding about these concepts should help dietitians reflect on their own perspectives and practice.


Asunto(s)
Dietética/métodos , Promoción de la Salud/métodos , Estilo de Vida , Obesidad/psicología , Obesidad/terapia , Adulto , Imagen Corporal , Canadá , Consejo , Femenino , Grupos Focales , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Autoimagen
16.
J Am Diet Assoc ; 105(8): 1275-9, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16182645

RESUMEN

This study describes Canadian dietitians' approaches to counseling adults seeking weight-management advice. Fifteen focus groups were conducted at seven sites across Canada. The participants, most of whom worked in clinical or private practice, discussed their approach to specific weight-management counseling scenarios, including women clients with and without associated risk factors (impaired glucose tolerance, hypertension, family history of cardiovascular disease) and long histories of dieting. Results indicate that participants used a lifestyle approach for weight-management counseling, where the main goal was improved client health through healthful eating and increased physical activity. In contrast to clients' perceived weight loss goals, participants rarely included weight loss as a goal for clients with no additional chronic disease risk factors. For clients with risk factors, some participants advocated moderate weight loss, while others aimed for health at any size. Participants also discussed the importance of clients' psychological well-being, particularly in relation to feelings about food and body image. Individualized approaches to setting goals, gathering information, and giving advice/educating were identified as key counseling strategies. Further research to evaluate the effectiveness of dietitians' weight-management approaches and additional counseling training for dietitians will enhance practitioners' skills and confidence in this area.


Asunto(s)
Consejo/métodos , Dietética/métodos , Ejercicio Físico/fisiología , Estilo de Vida , Obesidad/terapia , Adulto , Imagen Corporal , Canadá , Femenino , Grupos Focales , Conocimientos, Actitudes y Práctica en Salud , Promoción de la Salud , Humanos , Masculino , Obesidad/dietoterapia , Obesidad/epidemiología , Obesidad/psicología
18.
Cladistics ; 9(3): 275-304, 1993 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34929957

RESUMEN

Abstract- Data scored for cladistic analyses may be quantitative or qualitative, continuous or discrete, and show overlapping or non-overlapping values between taxa. Quantitative and qualitative are modes of expression of data, while continuous or discrete refer to properties of the set of numbers that express the data; both these pairs of terms have been confused with overlapping and non-overlapping. The degree of overlap of values between taxa is often used to filter characters in cladistic analyses: if a minimum amount of overlap is exceeded, or a minimum amount of disjunction not reached, characters are rejected as "not cladistic". However, this rests on a confusion between features of taxa and features of individual organisms (attributes). Cladistic characters are features of taxa, and comprise frequency distributions of attribute values over individuals of a taxon. Cladistic characters logically cannot overlap, although taxa may have overlapping attribute values. Thus, a priori rejection of characters that have overlapping attribute values is non-sensical. Such data may still be rejected from consideration for cladistic analysis if it could be demonstrated that they contain little recoverable phylogenetic signal. Few published analyses have empirically tested this. An analysis of overlapping morphometric data from three series of Banksia suggests that, at least in these cases, they map phylogeny almost as accurately as more conventional, qualitative morphological data. While more such tests are required, morphometric data should not be rejected a priori from cladistic analyses.

19.
Cladistics ; 4(1): 23-42, 1988 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34933494

RESUMEN

Abstract- A cladistie analysis of Angophora Cav. used a data set dominated by quantitative morphological characters. These were coded into multistates using Generalized Gap-Coding, and treated as ordered sequences of stales. The reasons for choosing an ordered over an unordered sequence are discussed. A branch and bound method yielded one minimal-length, unrooted tree. Because of uncertainty in the position of the root, five cladograms were derived from the unrooted tree. The consensus cladogram comprises four main clades. The consensus cladogram was used for a biogeographic study using component analysis, which generated a single statement of relationships for five areas of eastern Australia. An infra-generic classification of Angophora comprising four series corresponding to the four main clades, and two subseries, is presented. The following new names are published: Angophora series i>Floribundinae, series Subvelutininae, series Bakerinae. subseries Costntitac. Angophora leiocarpa: L. Johnson ex G. Leach) K. R. Thiele and P. Y. Ladiges and A.paludosa (G. Leach) K. R. Thiele and P. Y. Ladiges are published as new combinations.

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