CLADISTICS AND FAMILY LEVEL CLASSIFICATION OF THE GENTIANALES

Abstract— The most recent classification of the angiosperm order Gentianales (Thorne, 1992) includes four principal families: Apocynaceae, Gentianaceae, Loganiaceae, and Rubiaceae. Ever since Bentham (1857) the status of Loganiaceae has been questioned, and several segregates of that family have been proposed both before and after his treatment. In this study we present cladistic results that show Loganiaceae, sensu lato, to be a paraphyletic group definable only by plesiomorphies, with members showing closest relationships to other families of the order. As the impact of different character-state representations of polymorphic terminals remains largely untested, our morphological and phytochemical data were analysed both with restricted polymorphism coding as well as with the monomorphic "subtaxon" recoding method of Nixon and Davis (1991). Both approaches yield highly compatible results, and we here discuss a new classification of the Gentianales based on (i) monophyletic groups identified by outgroup analysis, and (ii) the maximal portrayal of evidence provided by subtaxon polymorphism recoding. Most prominently, the Loganiaceae sensu lato are divided into four segregate families, two previously named (Loganiaceae sensu stricto and Strychnaceae), and two defined as a result of this study (Gelsemiaceae, L. Struwe & V. A. Albert, stat. nov. and Geniostomaceae, L. Struwe & V. A. Albert, fam. nov.). Apocynaceae (incl. Asclepiadaceae), Gentianaceae (incl. Loganiaceae—Potalieae), and Rubiaceae remain as monophyletic families. Outgroup analysis supports both the monophyly of the Gentianales as well as the exclusion from the order of Buddleja, Desfontainia, Plocosperma, Polypremum , and Retzia (all Loganiaceae sensu Leeuwenberg and Leenhouts).     

CLADISTICS OF THE BRYOPSIDALES: A PRELIMINARY ANALYSIS

The Bryopsidales contains some of the most species rich and ecologically dominant algae in tropical ecosystems. However, the evolutionary relationships among the 29 genera and several hundred species of this order remain poorly resolved. Because of a lack of known reproductive characters for many taxa, evolutionary hypotheses grouped genera by similarities in morphological characters. To apply standard cladistical analyses to further our understanding of this group, this study presents the first comprehensive compilation of reported morphological, reproductive, and subcellular characteristics for genera in the Bryopsidales. Computer-assisted cladistical analyses ultimately identified phylogenetically informative and uninformative characters. Although the topology of the trees generated in this study is expected to change as additional data are added to this matrix, many traditional groupings and recent groupings based on molecular data were supported.     

THE CLADISTICS OF IDEAS (LEPIDOPTERA, DANAINAE)

Abstract— Males of Idea tambusisiana , previously unstudied, lack the only known unequivocal synapomorphy associating the constituent members of Idea . Further cladistic analyses were performed on an expanded data matrix containing two characters alternatively coded in binary and multistate form. Two topologies were obtained of which one, in which I. tambusisiana remains internal to the genus, is accepted following consideration of information content and assessment of the supporting character states. A character analysis is also performed in which the problem of ambiguous charater state assignments to the internal nodes of the cladogram is examined. Biogeographic implications of the results are discussed with respect to areas of endemism in southeast Asia, the origin of Sulawesi (Celebes), and vicariance/dispersal models intended to explain the distribution of Idea species in relation to the Makassar Strait.     

THE CLADISTICS OF AMAURIS BUTTERFLIES: CONGRUENCE, CONSENSUS AND TOTAL EVIDENCE

Abstract— Two data sets for 10 species of African milkweed butterflies (Nymphalidae, Danainae: one Danaus , two Tirumala , seven Amauris ) have been analysed cladistically, separately and in combination. One data set comprised 32 morphological characters, the other comprised 68 chemical compounds from male scent organs. Analysed separately, the two data sets produced six similar but non-identical minimum-length solutions. Analysed together, the combined data set of 100 characters produced a single minimum-length tree, identical to one of the three solutions for the morphological data set. The combined data produced a more informative result than congruence comparisons based on strict or combinable component consensus analysis. These results, together with re-analysis of a morphological data set for all 15 species of Amauris (which produced 12 minimum-length solutions), permit increased resolution of the existing classification of this Afrotropical genus, including the formal recognition of two subgenera, Amauris ( Amauris ) Hübner, and Amauris ( Amaura ) Geyer ( stat. rev. ). The fit of uniquely derived, unreversed chemical characters to the tree raises the possibility that stepwise additive evolution of semiochemicals may have occurred during cladogenesis of these mimetic butterflies. The implications for chemoecology and speciation are briefly discussed.     

PATTERN CLADISTICS OR EVOLUTIONARY CLADISTICS?

We can also put it like this. The introduction of an auxiliary hypothesis should always be regarded as an attempt to construct a new system; and this new system should then always be judged on the issue of whether it would, if adopted, constitute a real advance in our knowledge of the world—K. R. Popper.     

分支分类学中和谐性概念与和谐性分析方法

和谐性是分支分类学中的一个基本概念。本文给出一个和谐性的数学定义,称为Kexue和谐性。并在Kexue和谐性的基础上开发出一个新的和谐性分析方法。并对该方法在分支分类研究中的应用进行讨论。     

分支系统学简介

分支系统学是本世纪70年代以来发展起来的一个新的系统学派。本文扼要地介绍了分支系统学的创立、历史和发展,分支系统学的基本概念、特征分析法以及分支系统学的广泛应用给现代生物系统学所带来的广泛影响和冲击。     

PHYLOGENETIC RETICULATIONS AND CLADISTICS: DISCUSSION OF METHODOLOGICAL CONCEPTS

Abstract— Some problems associated with a cladistic treatment of complex taxa (hybrids and holobionts) are reviewed and discussed. The authors recommend aplication of standard cladistic analysis to all taxa, regardless of their supposed mode of origin. The position of a complex taxon depends entirely on the set of characters it shares with other taxa. This approach is preferable, because there are no means to distinguish deductively between various kinds of character conflicts (the recognition of one character as incongruous with others says nothing about its evolutionary origin). All other approaches have been proposed so as to reflect the topology of reticulate phylogenetic trees, but, at the same time, they require prior knowledge of the complex nature of a taxon.     

MORPHOMETRICS AND CLADISTICS: MEASURING PHYLOGENY IN THE SEA URCHIN ECHINOCARDIUM

A phylogenetic approach to the study of evolutionary patterns is based on taxic homologies (synapomorphies). In contrast, the recognition of evolutionary processes (namely heterochronies) involves analysis of the entire morphology. Recent developments in geometric morphometry permit analysis of morphological similarities grounded in operational homologies. Such morphometric techniques are explored (1) at the level of evolutionary processes, and (2) as a complement in exploration of phylogenetic relationships. To examplify this, we perform a two-part study of the ontogeny and phylogeny of the spatangoid sea urchin Echinocardium. First, a phylogenetic analysis of ten Recent species in the genus is performed on 18 informative characters of the test. Second, morphological divergences among the species are analyzed using procrustean (superimposition) methods based on 49 homologous points. An additive distance tree is built from a matrix of morphometric distances among adult specimens. This tree is fully congruent with the phyletic results. Ontogenetic processes are explored by inserting ontogenetic series into the analysis. A distance tree including the juvenile stages shows that the general evolutionary trend of the genus is peramorphic, but species-to-species comparisons attest that no general clinal trend exists. Our analysis emphasizes the importance of morphometric approaches in evolutionary studies (1) for the understanding of heterochronies; (2) to trace the morphological implications of phylogenetic patterns; and (3) to estimate the impact of homoplasies.     

PHYLOGENETIC SELECTION OF A RESOURCE: A NEW USE FOR CLADISTICS

A phylogenetic model for the selection of commercial resources using the cladistic method is proposed. The group selected as an example was the marine agarophyte red algal genus Gracilaria Greville. We suggest the use of the cladistic principle of evolutionary transformational series in order to test the quality of agars instead of the assay‐herror traditional method that consumes time and budget. If we asume that the “good quality of agar” in extant taxa is a sinapomorphic character (but not a reliable taxonomic one), then taxa included in the same monophiletic clade in which the species with “good quality of agar” are, has a high evolutionary posibility to share that character. In order to do this we have to incorporate to the set of available specific characters, those of the taxa actually used as a agar source but not present in the area under scope. A complete set of the basic cladistic data required for run the most popular program currently in use (PAUP) are provided. We applied the model to the Mexican Atlantic species and found that, using Gracilaria chilensis and G. cornea as “indicator taxa,” and found Mexican populations of G. crassissima, G. caudata, G. cervicornis and Gracilariopsis lemaneiformis are candidates for a study of yield and agar properties.