Keel flowers of the Polygalaceae and Fabaceae: a functional comparison

Although the superficial similarity between Polygalaceae and Fabaceae flowers is well known, a comparison between their recently more precisely defined 'keel flowers' reveals a wealth of functional congruences with regard to visual attraction, flower mechanics (interplay of fixed and mobile floral parts, presence of special contrivances such as tongue guide, foot handles, pollen cache, etc.), pollen presentation and nectar storage. Although keel flowers are principally addressed to bees, the increasingly pronounced fusion of floral parts gave rise to tubular flowers and has widened the spectrum of pollinators in the Polygalaceae. The intimate functional correspondence does not affect the assessment that the floral architecture (in terms of homologies) is quite different between the families. This is discussed with reference to the sistergroup relationship of the two families emanating from molecular systematics.     

Higher taxa: Reply to cartmill

Ian Tattersall is a curator emeritus at the American Museum of Natural History. He has worked on lemur systematics and ecology as well as paleoanthropology, where his special interest is in hominid diversity and cognitive evolution.     

Is there a direct ontogenetic criterion in systematics?

Much recent literature focuses on whether ontogenetic information can be used as a direct criterion for determining the polarity of character trasformations in systematic analysis. This paper reviews the relevant literature and concludes that the ontogenetic criterion is dependent on parsimony rather than the sequence observed during ontogeny. It is not, therefore, based on the discredited arguments of recapitulation. From the perspective of phyologenetic systematics the ontogenetic criterion is a valid means of polarizing character transformations that represents a special case of a broader methodology involving parsimony. The alternative perspective perspective of patttern cladistics holds that polarity should be contained within the data and not imposed upon it. Thus, ontogeny is not required to polarize characters, but ontogenetic information can generate unequivocal character interpretations in terms of the relative generality of related attributes, and in the sense that absence precedes presence. Furthermore, ontogeny is central to systematics, providing empirical evidence of character transformation, information on the whole life cycle and an escape from systematics being teleologically related to phylogenetic inference and the theory of evolution.     

The progress of DNA analyzing techniques and its impact on plant molecular systematics

Recent advances in manipulating nucleic acids have opened a new research field called plant molecular systematics. This short review provides an overview of molecular techniques which have been used in the analysis of DNA molecules for the study of plant systematics, with a special emphasis on PCR. The early application of DNA analysis, DNA/DNA hybridization, has not become popular with plant systematists, because of several disadvantages inherent in the method. The survey of restriction fragment length polymorphisms (RFLPs), on the contrary, has become one of the preferred methods used by plant molecular systematists, since the method is relatively easy to perform. Although unambiguous data can be obtained by both long-range restriction mapping and nucleotide sequencing, these approaches may have limited use in plant molecular systematics because of their laborious experimental procedures relying on conventional molecular cloning techniques. To date, PCR based analyses of the DNA molecule seem to be the most suitable experimental approach for plant molecular systematics. Several advantages of the method have changed both the quality and quantity of the DNA data. Further application of PCR to plant molecular systematics will open up a new era in the field. The present paper is based on the contribution which was read in a symposium entitled “Organellar DNA Variations in Higher Plants and their Taxonomic Significance”, at the 50th Annual Meeting of the Botanical Society of Japan in Shizuoka on October 2, 1990, under the auspices of the Japan Society of Plant Taxonomists.     

The current systematics and taxonomy of the powdery mildews (Erysiphales): an overview

A brief survey of the current systematics and taxonomy of powdery mildews (Erysiphales) is given with special focus on new characters used for taxonomic purposes as well as new approaches, methods and techniques. The structure of the family Erysiphaceae based on phylogenetic results is summarized, and the current, strongly increased number of powdery mildew taxa in a planned new monographic treatment of this fungal group is given and compared with the old monograph from 1987.     

A phylogenetic analysis of the land plants

Phylogenetic systematics (cladistics) is a theory of phylogeny reconstruction and classification widely used in zoology. Taxa are grouped hierarchically by the sharing of derived (advanced) characters. The information is expressed in a cladogram, a best estimate of a phylogeny. Plant systematists generally use a phenetic system, grouping taxa on overall similarity which results in many groups being formed, at least in part, on the basis of shared primitive characters.
The methods of phylogenetic systematics are used to create a preliminary cladogram of land plants. The current classification of land plants is criticized for its inclusion of many groups which are not monophyletic.
Objections to the use of phylogenetic systematics in botany, apparent convergences within major groups and frequent hybridization, are shown to be invalid. It is concluded that cladistic analysis presents the best estimate of die natural hierarchy of organisms, and should be adopted by plant systematists in their assessment of plant interrelationships.     

Grundsätze der phylogenetischen Systematik (Eine praxisorientierte Übersicht)

The essential elements of phylogenetic systematics in the sense of Hennig are emphasized: The search for synapomorphies based on a special method of comparative morphology, and the aim of an exclusive use of synapomorphies for kinship proof and the basis of systematics. Special aspects of comparative morphology are: “Directed comparisons” steady reciprocal reflection between comparative morphological result and the system methodical efforts for the realization of distinctive details, comprehensive documentation and functional interpretation. This is equally true for recent and fossil forms. Most suitable for the method (in the sense defined above) are groups with numerous differentiated morphological characters, which can also be preserved in the fossil state. The less this is the case the less is the chance for achieving necessary numbers of well proven synapomorphies. Even so, it is not permitted—for those who want to perform phylogenetic systematics in the sense of Hennig—to use convergences, parallelisms or symplesiomorphies in the sense of “synapomorphies” as phylogenetic arguments for kinship relations. Numerous examples and diagrams demonstrate the methodological proceeding, and differences towards other methods of phylogenetical reconstruction and interpretation. Special attention is paid to direct and indirect conclusions drawn from fossils: Time of origin of characters, stem groups and *groups; predictions concerning the appearance (set of characters) of fossils and simultaneous existence of “neighbour groups” (sister groups, and more distantly related taxa).     

Study of the soluble white muscle tissue proteins from fifteen Sparidae species

Soluble proteins of white skeletal muscle tissue of 15 species of Sparidae were analysed. Species-specific electrophoretic and isoelectric focusing patterns were found. Some bands exhibited the same mobility at genus level or at subfamily level, others differed significantly.
Considerable similarity was observed in the species of the genera Spams, Pagellus and Diplodus . Significant differences in the protein bands were noted between the contained subfamilies Denticinae, Sparinae and Boopsinae, confirming the existence of three separate phyletic lines within the family Sparidae.
This study has shown that in these species there is a similarity between classifications based on morphological data and those derived from biochemical studies.
Variation within species can be corrected for by carrying out multiple inter-specific comparisons and determining the variance of the similarity coefficients. Closely related species have similar patterns and, thus, higher similarity coefficients.
The discrepancy in similarity matrices based on morphology and white skeletal muscle tissue proteins of sea bream species shows that electrophoretic methods provide additional information relevant to the systematics of fishes.
Further work on comparison on soluble red muscle proteins of these species is proposed.     

Nuclear markers reveal that inter-lake cichlids' similar morphologies do not reflect similar genealogy

The apparent inter-lake morphological similarity among East African Great Lakes' cichlid species/genera has left evolutionary biologists asking whether such similarity is due to sharing of common ancestor or mere convergent evolution. In order to answer such question, we first used Geometric Morphometrics, GM, to quantify morphological similarity and then subsequently used Amplified Fragment Length Polymorphism, AFLP, to determine if similar morphologies imply shared ancestry or convergent evolution. GM revealed that not all presumed morphological similar pairs were indeed similar, and the dendrogram generated from AFLP data indicated distinct clusters corresponding to each lake and not inter-lake morphological similar pairs. Such results imply that the morphological similarity is due to convergent evolution and not shared ancestry. The congruency of GM and AFLP generated dendrograms imply that GM is capable of picking up phylogenetic signal, and thus GM can be potential tool in phylogenetic systematics.     

Transformation Series as an Ideographic Character Concept

An ideographic concept of character is indispensable to phylogenetic inference. Hennig proposed that characters be conceptualized as “transformation series”, a proposal that is firmly grounded in evolutionary theory and consistent with the method of inferring transformation events as evidence of phylogenetic propinquity. Nevertheless, that concept is usually overlooked or rejected in favor of others based on similarity. Here we explicate Hennig's definition of character as an ideographic concept in the science of phylogenetic systematics. As transformation series, characters are historical individuals akin to species and clades. As such, the related concept of homology refers to a historical identity relation and is not equivalent to or synonymous with synapomorphy. The distinction between primary and secondary homology is dismissed on the grounds that it conflates the concept of homology with the discovery operations used to detect instances of that concept. Although concern for character dependence is generally valid, it is often misplaced, focusing on functional or developmental correlation (both of which are irrelevant in phylogenetic systematics but may be valid in other fields) instead of the historical/transformational independence relevant to phylogenetic inference. As an ideographic science concerned with concrete objects and events (i.e. individuals), intensionally and extensionally defined properties are inconsistent with the individuation of characters for phylogenetic analysis, the utility of properties being limited to communicating results and facilitating future rounds of testing.     

Systematics Agenda 2000: an historical perspective

The publication of Systematics Agenda 2000 in February, 1994 represented an historic event in the collaboration of the systematic biology community designed to set a research agenda for a twenty five year period across the areas of basic and applied systematics. How the community came to take the initiative to produce such a consensus is outlined. Of special interest is the emergence of the Systematics Agenda 2000 initiative from a North American perspective to a truly global enterprise.     

块菌属研究概况和重要进展

块菌属(Tuber F. H. Wigg.)是一类具有重要经济和生态价值的子囊菌门地下生的外生菌根真菌。因能与多种树木共生而在森林生态系统中占据重要地位, 子囊果具独特的香味使其在欧洲市场久负盛名, 一直以来, 该属颇受国内外学者的广泛关注。本文综述了该属在系统分类学、生态学、生物化学及人工栽培等方面的研究概况和进展, 分析了目前研究中存在的问题及尚待解决的主要问题, 并提出了针对性的建议。     

The life cycle ofAcetabularia (Dasycladales,Chlorophyceae): A compilation of evidence for meiosis in the primary nucleus

Summary The life cycle ofAcetabularia is described with special reference to nuclear divisions. Recent arguments, derived from the fields of cytology, genetics and systematics are in favour of the hypothesis, that meiosis occurs during the division of the primary nucleus. This hypothesis is summarized in a schematical representation of the whole life cycle.     

A problem of truth in biological systematics

A possibility to put a question of truth of knowledge in biological systematics is studied. It is shown that the problem of truth in reference to systematics is wider than a question of classified information reliability. Prerequisites needed for logically accurate formulation of a definition and criteria of truth are considered. It is shown that such prerequisites are present in taxonomic practice, namely in a process of diagnosis compiling. Philosophical analysis of this work has been carried out. Interpretation of an essence of systematics as classification is connected with use of classical concept of truth (which defines truth as correspondence between knowledge and object) in its undeveloped form. Carried analysis allows supposing that a theory of systematics based on diagnostics rather than on classification would be more prospective. Use of imperfect concept of truth can be seen also in notions that system of taxa must reflect its evolutionary history. Development and modernization of Aristotle's orientation to discovery of the object form can become an alternative to such opinions. An aspiration to achieve the truth is the main motive of systematic work. An influence of this aspiration on a selection of purposes of taxonomic work and theoretical comprehension of its bases is shown. Such features of modern biological systematics as its accessibility for new results, criticism in respect of external morphological characters, and interest in intraspecific variability are connected with this aspiration. This motive comes into contradiction with a tendency to withdraw the problem of truth as such, which takes place in some brunches of theoretic systematics.     

Über die Beziehung zwischen Systematik und Evolution

The relation between systematics and evolution The theoretical and methodological decoupling of pattern analysis from the causal explanation of the hierarchical order of nature by the hypothesis of descent with modification is defended. This contrasts with the philosophy of phylogenetic systematics which views acceptance of evolutionary theory as a necessary prerequisite for research in systematics.     

Falsifications and corroborations: Karl Popper's influence on systematics

Over the last three decades, the philosophy of Karl Raimund Popper has had a strong influence on the field of systematic biology. Unequivocally, no other philosopher's work has had such an influence during this formative period in systematics. Much, but not all, of the early discourse on Popper and systematics dealt with the philosophical basis of systematics as a science. More recently Popper's work has been discussed in the systematics literature in relation to specific methodologies such as parsimony and maximum likelihood. In this paper, we provide the reader with a concise summary of Popper's ideas relevant to systematics, review the systematic literature invoking or declining Popper's importance to the field, and make a recommendation for the future course of philosophical thinking in systematics. We try to make clear various authors' interpretations of Popper's work and how those interpretations have impacted systematic thought. Although the reader may come away from this review with a clearer idea of Popper's relevance or lack thereof, our primary hope is that the reader will be compelled to question him- or herself about the philosophical basis of the systematic work that he or she does, and to delve into the literature herein cited. We begin by presenting a synopsis of Popper's philosophical views to allow those views to be placed in the context of systematics.     

Amphibious Shelter-Builder Oniscidea Species from the New World with Description of a New Subfamily,a New Genus and a New Species from Brazilian Cave (Isopoda,Synocheta, Styloniscidae)

The new subfamily Iuiuniscinae, Styloniscidae, is erected for the new genus Iuiuniscus and the new species I. iuiuensis, which is described from cave of the State of Bahia, Northeastern Brazil. A special ecological character is shown here for the first time for a New World Oniscidea: the construction of mud shelters. An introduction addressing the systematics of Synocheta with emphasis on Styloniscidae Vandel, 1952 is provided, as well as general comments about the dependence of water in some Oniscidea and ecological traits of amphibious Synocheta. The problems referring to nomenclature, taxonomy and the interrelationships in Styloniscidae are discussed.