Taxonomy Structure Research Articles

THE CORRELATION BETWEEN TAXONOMY AND PERISTOME STRUCTURE IN THE BRYACEAE

THE CORRELATION BETWEEN TAXONOMY AND PERISTOME STRUCTURE IN THE BRYACEAE

The structure in persons' implicit taxonomy of emotions

Persons' classifications of emotions are viewed as based on an implicit taxonomy of emotions. This implicit taxonomy has sometimes been thought of as a bipolar dimensional system within which are located all the various emotion-descriptive categories (fear, anger, happiness, etc.). A dimensional taxonomy of this kind assumes that all emotion categories are interrelated in a systematic way. More often, however, the implicit taxonomy has been thought of as a list of separate emotions. A taxonomy in the form of a list typically presupposes that emotion categories are either synonymous, independent, or mutually exclusive. McNair, Lorr, and Droppleman's Profile of Mood States (San Diego: Educational and Industrial Testing Service, 1971) is one such list of emotion categories and was therefore examined in two studies for the actual interrelationships among its categories. To examine intraindividual relationships, 45 subjects rated the emotional state posed in each of 32 videotape segments. Even at the level of the individual subject, results showed that emotion categories are systematically interrelated and can be accounted for reasonably well by a system of three bipolar dimensions: pleasure-displeasure, arousal-sleepiness, and dominance-submissiveness. Evidence for the same bipolar system was also obtained in a second study, which examined interindividual differences in the self-reported emotional states of 343 subjects.

The genus Capillospirura Skrjabin, 1924 (Nematoda: Cystidicolidae) of sturgeons

Capillospirura Skrjabin, 1924 (Nematoda: Cystidicolidae) is redefined on the basis of a study of specimens from old world sturgeons. It can be distinguished from the closely related Ascarophis van Beneden, 1870 by a bidentate plate-like structure which arises from the anterolateral wall of the buccal cavity. Capillospirura is also characterized by narrow pseudolabia with a ridge-like apex, submedian labia, and sublabia in subdorsal and subventral quadrants of the oral opening. Three species are assigned to Capillospirura: C. ovotrichuria Skrjabin, 1924 and C. argumentosa (Skrjabina, 1966) n. comb. (= Ascarophis argumentosus) from old world sturgeons and C. pseudoargumentosa (Appy and Dadswell, 1978) n. comb. (= Caballeronema pseudoargumentosus) from a new world sturgeon. The value of cephalic structure in cystidicolid taxonomy is discussed.

Fish coccidia: critical notes on life cycles, classification and pathogenicity

Abstract. The present knowledge of oocyst morphology, life cycles, classification and pathogenicity of eimeriid coccidia infecting fishes is reviewed. Compared with typical Eimeria species from higher vertebrates, fish coccidia, currently classified as all belonging to the same genus, differ in having, as a rule, a thin oocyst wall and endogenous sporulation. Some species possess a bivalved sporocyst, a structure and consequently an excystation mechanism, essentially different from that of the genus Eimeria. An analysis of the life cycles of more than 120 recorded species of fish coccidia has shown six different types of developmental patterns. The life cycles offish coccidia are compared with the life cycles of coccidia in general. None of the fish coccidia having a sporocyst with a Stieda body sporulates exogenously and therefore do not display a true eimerian developmental pattern. In view of the importance of sporocyst structure and developmental patterns in taxonomy, the revalidation of Labbé's genera Goussia and Crystallospora is proposed along with the establishment of a new genus, Epieimeria n.g. Most of the species offish coccidia are left within the genus Eimeria until new data make possible their correct classification. Detailed data on histopathological changes are available only in infections by two carp‐infecting species, E. carpelli and E. subepithelialis and E. funduli infections in killifishes. The potential threat of coccidiosis in fishes reared under intensive conditions requires a thorough study of the pathogenicity of further species infecting commercially important hosts.

A conceptual approach to the description and analysis of an historical urban system

Barker D. (1978) A conceptual approach to the description and analysis of an historical urban system, Reg. Studies 12, 1–10. A set-theoretic approach to modelling urban systems at a particular point in time is outlined and applied to nineteenth century Somerset. The multivariate supply of retail and service facilities, i.e. the output of the system, is shown to be ordered, and is used to classify centres, using a non-hierarchic grouping technique. The hierarchic structure of the resultant taxonomy is verified using unidimensional scaling methods. The approach can be applied to crude binary data records of the presence or absence of supply facilities and can be spatially and temporally replicated whenever similar data is available.

Taxonomy and molecular structure

Abstract The number of structural variants possible on the molecular level as expressed, say, by numbers of possible isomers of component molecules is here compared to the number of individuals that can make up any taxon in a finite world. One finds that the former number (the size of the combinatorial ‘master set’) is invariably vast compared to the number of individuals in a taxon. It is next pointed out that this relationship of vast multiplicity (quite different in nature from anything outside the structural world of organic compounds) can confidently be taken as the basis for what, on a more philosophical view, is described as the autonomy of organic life.

Breeding and marsupial development in laboratory-maintained Parathemisto gaudichaudi (Amphipoda)

Parathemisto gaudichaudi (Guerin) (= P. gracilipes, Sheader & Evans, 1974) is a species of planktonic hyperiid amphipod which occurs in temperate and subpolar regions in both hemispheres (Dunbar, 1964; Kane, 1966; McHardy, 1970, Ph.D. thesis, Edinburgh University).Our previous studies have dealt with the taxonomy (Sheader & Evans, 1974), feeding and gut structure (Sheader & Evans, 1975), and morphological variation (Sheader, 1975) of P. gaudichaudi. These studies involved the routine maintenance of the species in laboratory conditions, allowing behavioural and developmental data to be gathered. The present paper deals with fertilization of the eggs and subsequent development up to the time of release from the marsupium. Animals were collected at a station 5 miles east of Blyth, Northumberland (55° 07′ N, 1° 22′ W). Laboratory culture is described in previous papers (Sheader & Evans, 1974, 1975).

On the taxonomy and fine structure of some hyperthermophilic saccharolytic Clostridia.

Using 13 strains isolated from extraction juices of sugar beet factories and comparative strains of the species C. thermosaccharolyticum and C. tartarivorum, a new description of the species C. thermohydrosulfuricum is provided.

Expanding Horizons in the Recognition of a Phylum

The field of systematics has often been ridiculed, especially by biologists engaged in other aspects of science. Occasionally the writings of some systematists have merited this lack of respect but this fact provides neither reason nor excuse for belittling the entire field. The chief cause for contempt of systematics has been a lack of appreciation on the part of other biologists for the methods and objectives of taxonomic work. There has been a wide spread but fallacious belief that physical and chemical phenomena are objective realities while species and other taxonomic concepts are purely subjective creations of the human imagination. The apparent disregard for taxonomy has some times been voiced in the figure which rates the taxonomists as the hod-carriers of science. Those who hold such derogatory attitude toward the objectives of the taxonomist seem to have forgotten that the mortar carried by the hod-carrier is the stuff which gives stability to the wall. Without cooperation of hod carriers, the walls of biology would be but a loose pile of toppling bricks or stones, lacking pattern and orderliness. However, if the taxonomist is rated as but a menial laborer whose function is that of carrying the cohesive mortar for the edifice of biology, how much lower in the social scale of scientific castes must be the student of nomenclature who inspects the bricks for conformity and rejects those with flaws before they weaken the wall. All too often faulty material escapes first inspection and then part of the structure must be torn down so that the defective units may be replaced. To carry the figure a bit farther; we might say that the student of nomenclature is the apprentice to the hod-carrier since it is he who moistens the sand of personal endeavor and the lime of public opinion with the water of common sense and precedent to form the mortar for binding together the units constituting the structure of taxonomy. Instead of attempting to organize a brief in defense of the fields and practices of taxonomy and nomenclature, this address will be devoted to tracing the growth of information regarding a single phylum, the Acanthocephala, or thorny-headed worms. In its history this group provides excellent material to illustrate the steps in the gradual expansion and evaluation of concepts in taxonomy. In the earliest days before the status of this group was understood, species now regarded as belonging within it were promiscuously assigned to various genera now recognized as representing several distinct phyla. By easy stages the knowledge of detailed

A Study of the Baculum in Some North American Microtinae

As a systematic tool, the os penis or baculum has received considerable study in recent years. Descriptive studies have been summarized by Gilbert (1892), while Burt (1936) has listed the important papers dealing with the use of this structure in taxonomy. Burt (ibid.) suggested that the internal situation of this structure does not expose it to the stresses and strains as are the bones of the limbs and skulls, and points out that its true character is less likely to be disguised by extraneous factors. He concludes that the characters of the baculum should indicate to a greater extent the real affinities of the animal. Few reports are available on the structure of the os penis in the voles and lemmings. The baculum of Arvicola arvalis has been figured by Gilbert (ibid.) but since this was illustrated at natural size, none of the trenchant characters can be observed. Tullberg (1899) has illustrated the baculum of Arvicola amphibius but the figure is so small that it is impossible to observe the precise characters. Didier (1943) has used the character of the baculum to ascertain the relationship of Arvicola t. terrestris, A. t. amphibius and A. t. monticola. Considerable variation exists within a species and variation with age is apparent (Plate 1). Nevertheless, specific characters are for the most part fairly well marked and enable the investigator to draw conclusions regarding the relationships existing between genera, and, to a lesser degree, species may be separated from one another on the structural character of the baculum.