Insect flotsam: an unstudied marine resource

Abstract. 1. Insect flotsam was obtained from marine pleuston samples from the English Channel (U. K.), off the Oregon coast (U. S. A.), and in the Gulf of California (Mexico).
2. Only ten orders of insects were represented, Coleoptera, Diptera and Homoptera being the most abundant.
3. Staphylinidae and Chironomidae were the most abundantly represented families taken from the English Channel, comprising 43% and 18% respectively of total insects sampled.
4. Aphididae comprised 39% of the Oregon Coast samples.
5. Aphididae (42%) and Cicadellidae (17%) accounted for 59% of the insects in the Gulf of California.
6. Fish may feed on surface insects at night and this may account for the lower numbers found in early morning samples.     

Aphyly: A Systematic Designation for a Taxonomic Problem

A taxon is aphyletic when it is deemed to be non-monophyletic or unresolved, therefore aphyletic taxa are a taxonomic problem rather than an evolutionary anomaly. A problem arises in systematics when taxonomic names assigned to aphyletic taxa are treated as if they were natural groups. In the absence of a taxonomic and systematic revision, anomalous taxa should be labelled as aphyletic without recourse to phylogenetic inference (i.e., interpretation). Doing so avoids the validation of aphyletic names and the creation of dubious results in fields that rely on systematic and taxonomic data.     

Characters: the central mystery of taxonomy and systematics

Taxonomic and systematic theory is hopelessly confused because the term character has nine different, previously confused, meanings. After a historical analysis, it is shown that some form pairs, one used in taxonomy (= operational identification of phenetic patterns of character x individual spread) and the other in systematics (= theoretical analysis of patterns of taxonomy). On the basis of a stratigramy model, names are given to each usage and are defined for taxonomy, then systematics, as necessary: component : (tax.) a defined bit-or-piece of one individual (no syst. meaning); homology : (tax.) conceptual identity of components of several individuals, attributable (syst.) to common ancestry; homology avatar : (tax.) case of recognized homology which (syst.) shows broad phylogenetic continuity (e.g. eye) (= character sensu Sokal and Sneath); homolostratum/homology state : (tax.) specified condition of a homology avatar whose distribution (syst.) enables cladogenetic happenings to be identified (e.g. colour:red/green/blue/etc.) (= character state of Sokal and Sneath); character sensu stricto : (tax.) homolostratum limited to a taxon which (syst.), with hierarchy, identifies chronological sequences of most cladogenetic happenings; taxonomoids : (tax.) mixed group of homolostrata, including yet unknown characters, that identifies a taxon and so (syst.) has same role as characters (= roughly symplesiomorphies); Ante- (Ah) and Post-(Ph) happening characters : (tax.) the hierarchy levels immediately above and below an empty level which (syst.) reveal a cladistic happening (= roughly one usage of synapomorphies and apomorphies).     

Polychaete systematics: Past and present

In this paper, we first demonstrate the historical background for the current unsatisfactory state of systematics of the polychaetes. We then briefly discuss our knowledge of internal and external structures. A review of the polychaete families makes up the third section; 81 families are treated in detail. Five families have been recently synonymized with others, and six families are too poorly known to be sufficiently characterized. Fossil polychaetes are briefly mentioned, with specific attention to problems associated with incorporating them in recent systematics.
The traditional separation in 'errant' and 'sedentary' polychaetes has increasingly become recognized as being unsatisfactory; however, the current trend towards grouping the polychaetes in many orders without specifying the relationships among the orders, is no more satisfactory. The lack of consistent morphological information is a major source of uncertainty. Intensive morphological studies should remove terminological ambiguities and alleviate some of the problems.     

Rhodococcal systematics: problems and developments

Various approaches that have been used in the development of a system of classification for the genus Rhodococcus are discussed. The application of chemotaxonomic, molecular systematic and numerical phenetic methods have greatly contributed to improvements in the systematics of rhodococci and related mycolic- acid containing actinomycetes. The genus currently encompasses twelve validly described species but improved diagnostic methods are needed to distinguish between them. In addition, evidence from 16S ribosomal RNA sequencing suggests that the genus is still heterogeneous.     

Morphology and systematics of the Scytopetalaceae

The present study is based on a re-investigation of the vegetative and reproductive structures of the West African family Scytopetalaceae. Special emphasis is paid to inflorescence morphology and seed anatomy. The inflorescences of all genera of Scytopetalaceae can be interpreted as derived from panicles through reductions and structural changes. Thyrsoids prevail, but panicles, botryoids and racemes occur as well. Within the family cauliflory appears as the derived condition. Seed coat structure is extremely simplified and very stable in the Scytopetalaceae. The horny endosperm contains amyloid as the main storage compound. The presence of two obviously different forms of ruminate endosperm indicates that rumination arose twice within the family. The neotropical genus Asteranthos (Lecythidaceae) agrees in almost all relevant characters with the Scytopetalaceae. Therefore the proposed inclusion of Asteranthos in the latter family is fully confirmed. Scytopetalaceae, Lecythidaceae, Foetidiaceae and Napoleonaeaceae apparently form a natural alliance. Two new subfamilies (Scytopetaloideae, comprising Scytopetalum, Oubanguia , and Asteranthos; Rhaptopetaloideae comprising Rhaptopetalum, Pierrina and Brazzeia ) are proposed and fully described.     

ComprehendingCornus: Puzzles and progress in the systematics of the dogwoods

Dogwoods evolved in two main lineages, a red-fruited line in which the inflorescences have basal bracts, and a blue-(or white-)fruited line in which the bracts are rudimentary or lacking. The 15 “red-line” species are mostly well marked, whereas “blue-line” species—numbering roughly 50 if some newer treatments be accepted—are mostly hard to tell apart. Red-line ovules are tenuinucellate, blue-line ovules crassinucellate. Dividing the red line separates cornelian cherries from the showy-bracted species; dividing the latter separates dwarf cornels from big-bracted dogwoods. Adding in the blue line there are thus four subgroups, which differ with regard to inflorescences— and with regard to iridoid glucosides, among other things. I downplay further subdivision (into opposite- and alternateleaved blue-line groups, for instance) and focus on few traits because I aim to trace the subgroups backward in the fossil record, to decide the direction of evolutionary changes, and to infer the causes for divergence. Unlike pollen, leaves, and wood, fossil dogwood fruits can often be assigned to one of the four subgroups and sometimes to a species group within a subgroup.Dunstania (based on fruits from England’s early Tertiary and here transferred toCornus’s cornelian cherry subgroup) or something close to the dunstanias gave rise to modernC. volkensii of Africa and four related species found today in California and Eurasia. Fossil fruit-stones of the blue line, like their modern counterparts, can be subglobose, compressed and asymmetric, fluted, or topped by a deep depression. Such a deep depression serves to link a fossil to the extant speciesC. alternifolia andC. controversa, but other features of the blue-line fruitstones, overlapping and less constant, cannot be used to prove a fossil’s tie to groups within the blue line. Evidence of several kinds makes the blue-line dogwoods oldest and connectsCornus to the nyssoids:Nyssa, Camptotheca, andDavidia. Commonly called Nyssaceae after 1910, when Wangerin got their traits wrong, the nyssoids are surer relatives ofCornus than any of Wangerin’s (“Das Pflanzenreich”) cornaceous genera.Mastixia, however, may be the actual sister group because it shares withCornus 1-celled 2-armed hairs that nyssoids lack.Cornus, nyssoids, and mastixioids (modernMastixia and its closest fossil allies) are here regarded as the true Cornaceae. Other genera once thought to be cornaceous are doubtfully to not at all related. As is now widely known, discordant features makeCorokia andKaliphora (for example) out of place in the Cornaceae, butAucuba andGarrya (for example) are neither easily excluded by a listing of their traits nor easily included by construction of branched diagrams. The novelty that brought about the radiation of true cornads was, I think, epigyny, followed fairly quickly by the hard endocarp and singleseeded locules. Mastixioid fruits of the late Cretaceous were dry or leathery and smaller than their successors. This suggests that early members of the family spread abiotically or by means of animals that ate whole plants. Bigger, fleshier fruits came later through interaction with evolving frugivores. The cause of early radiation withinCornus probably was interaction with insect predators and pollinators. One species of the blue line escaped competition for spring pollinators by switching to fall flowering and thereby kept some traits that other dogwoods lost. Though birds are now the main dispersers of the dogwoods, rodents likely play a minor role, and monkeys likely played a major role when compound fruits evolved. Though gynoecial reduction was the rule in dogwoods,C. (Dunstania) multilocularis’s multiple seed chambers reflect an evolutionary increase. I postulate that modernCornus’s 4-merous flower with 2-merous ovary has a strong developmental tie to pairing of the leaves and branches.     

Kluyveromyces: systematics since 1970

The taxonomy ofKluyveromyces has been the object of intense study since van der Walt's (1970) monograph. This is an account of the major developments and the classification to be adopted in the 4th edition ofThe Yeasts, a Taxonomic Study. The guiding principles that will be followed in eventual revisions of the genus are presented.     

Anthocyanins of the Sterculiaceae: Flavonoid scores and Hennigian phylogenetic systematics

Published results of the distribution of anthocyanins in the Sterculiaceae have been re-interpreted on the basis of the phylogenetic status of the compounds present. A flavonoid score system was less useful than a cladistic interpretation based on Hennigian arguments.     

Phylogeny and systematics of the Trogidae (Coleoptera: Scarabaeoidea)

Abstract. A cladistic analysis of the Trogidae using eighteen adult characters resulted in a monophyletic group from which the genera Glaresis Erichson, Afroglaresis Petrovitz and Cryptogenius Westwood are excluded. The Trogidae as here defined comprises three genera, Trox Fabricius (with two subgenera, Trox and Phoberus Macleay), Omorgus Erichson (with three subgenera, Omorgus, Afromorgus subg.n. and Haroldomorgus subg.n.) and Polynoncus Burmeister.     

Phylogenetics and the future of helminth systematics

Phylogenetic systematics is a relatively new formal technique that increases the precision with which one can make direct estimates of the history of phylogenetic descent. These estimates are made in the form of phylogenetic trees, or cladograms. Cladograms may be converted directly into classifications or they may be used to test various hypotheses about the evolutionary process. More than 20 phylogenetic analyses of helminth groups have been published already, and these have been used to investigate evolutionary questions in developmental biology, biogeography, speciation, coevolution, and evolutionary ecology.