Systematic Zoology

The generic name Ichthyosporidium Caullery and Mesnil, 1905, was created for two original species. One of them was probably a fungus and the other a protozoan, but neither was ever designated as type-species. In subsequent studies this name has been applied by some authors to organisms known to be fungi and by other authors to quite different organisms which are generally conceded to be protozoans. In this study the protozoan originally included in the genus, 7. phymogenes, later corrected to I. giganteum (Thelohan, 1895) Swarczewsky, 1914, is selected as type-species and the generic name is thereby reserved for the protozoans. The other original species, I. gasterophUum C. and M., 1905, is transferred to genus Ichthyophonus Plehn and Mulsow, 1911.

Evidence is presented for the thesis that a taxometric analysis using haphazardly assembled, equally weighted characters results in a haphazard classification, at least in the Basidiomycetes. We consider that not all characters, in the currently accepted sense of that word, contain equal amounts of phylogenetic information, and that a proper taxonomic value can be placed on each character only if its degree of conservatism within the group is understood. So far, not only has it been impossible to instruct a computer to take conservatism into consideration, but also the limitations of the taxonomist's knowledge about homology and analogy in the fungi restrict his ability to designate characters in taxometric terms.

Species of birds sympatric on islands frequently differ from each other in bill length by a larger amount than do their mainland relatives. Differences between similar species in body size, as indicated by wing length, are smaller than differences in bill length. This suggests that a major adaptation of island birds to potential competitors is a change in feeding habitats. An alternative explanation of the bill features of island birds, that they have been selected for a species recognition function, may be applicable in some instances. But since pairs of species are usually different in plumage features, as well as song and behaviour, species recognition is probably achieved most frequently by these means and not by bill size or shape. Some data show that homogeneric species differ in numbers by a greater amount on islands than on the mainland. Differences in numbers and bill characteristics support the suggestion that for sustained coexistence the requirement of mutual ecological independence of closely related species is often greater on islands than on a mainland. This results from the restricted variety of resources and area of islands.

Wilkinson, Chris. (Department of Biological Sciences, Portsmouth Polytechnic, U.K.) 1970. Adding a point to a principal coordinates analysis. Syst. Zool., 19:258–263.—A new numerical method is given which is of value to taxonomists. It enables further species to be added to a previous principal coordinates analysis in order to find their phenetic relationships with the original set of species.

Chromosome numbers are reported for 30 species representing eight families of anurans. These, together with previously published records, provide some evidence of trends in numbers of chromosomes at the family level. With the exception of two genera of leptodactylids, diploid numbers range from 20 to 36 and haploid numbers, from 10 to 18 in anurans studied to date.

The relationships of 42 Canadian species of the mosquito genus Aedes were investigated by numerotaxonomic techniques, using the method of matching coefficients. Good agreement with conventional taxonomic arrangements was found when (1) adult mosquitoes and (2) adults and larvae together were considered, but with (3) larvae alone, the agreement was unsatisfactory. The prospects of numerical methods in taxonomy are briefly considered.

Sarich, Vincent M. (Dept. Anthropology, U. Calif., Berkeley 94720) 1969. Pinniped origins and the rate of evolution of carnivore albumins. Syst. Zool., 18:286–295. [Immunology; albumins; pinnipeds; phylogeny; evolution].—Data resulting from an immunological study of relationships among fissiped and pinniped albumins show that albumin evolution has occurred in a regular fashion in these taxa. This finding allows the conclusion that the pinnipeds share much more recent common ancestry with the canoids than either group does with the feloids. It is pointed out that it now appears possible to develop an internally consistent quantitative phylogeny for a group of species through the immunological study of a single protein found in that group.

Small specimens can be stored safely in vials, tightly stoppered with cotton and placed upside down in a larger jar. Due to the unavailability of tight jars, methods used in several institutions to prevent alcohol loss have been tried out. Either plastic tape (3M no. 472) or dipping in plastic coating (Uniroyal Adhesive no. 6273) appreciably slows evaporation. Seventy to eighty per cent alcohol is the best preservative; 40-70% isopropyl alcohol seems an excellent substitute, and is easily obtained. Methods of reconditioning dried specimens are controversial. All locality labels should be typed or mimeographed or the labels can be photo-offset, or Xerox copied on good bond paper.

In female Tetraopes tetraophthalmus there is significant heterogeneity in allometric growth ratios of prothoracic tubercle size and prothorax width among different areas of the range. This suggests that different relative growth rates in the formation of the adult prothorax may have been selectively favored in different areas of the range. However, males do not show the effect. Furthermore, the relationship between individual and population allomorphosis is also strikingly different in the two sexes; estimates of growth ratios at these two levels are similar in females, very dissimilar in males.

Karyotype evolution apparently involving Robertsonian centric fusion of chromosomes in iguanid reptilian species (Sceloporus clarki and Sceloporus magister) is consistent with the recent evidence pertaining to the evolution of North American Desert species of animals and plants derived from tropical and subtropical communities of the Madro-Tertiary Geoflora during the evolution of the North American Desert.

Qualitative identification and quantitative estimation both of aromatic biogenic amines and pharmacologically active polypeptides in the skin of amphibians appear to offer a valuable contribution to studies in taxonomy and evolution of this vertebrate class. Several examples of the accordance of the biochemical data herein reported with the data of traditional taxonomy are described for the neotropical family of frogs Leptodactylidae, but particular emphasis is laid on the striking correspondence between the systemic distribution of the spectra of biogenic amines and morphological taxonomy which is demonstrated by the species of the genus Leptodactylus.

Fitch, W. M. (Dept. Physiological Chetn., U. Wisconsin, Madison 53706) 1970. Distinguishing homologous from analogous proteins. Syst. Zool., 19:99–113.—This work provides a means by which it is possible to determine whether two groups of related proteins have a common ancestor or are of independent origin. A set of 16 random amino acid sequences were shown to be unrelated by this method. A set of 16 real but presumably unrelated proteins gave a similar result. A set of 24 model proteins which was composed of two independently evolving groups, converging toward the same chemical goal, was correctly shown to be convergently related, with the probability that the result was due to chance being <10−21. A set of 24 cytochromes composed of 5 fungi and 19 metazoans was shown to be divergently related, with the probability that the result was due to chance being < 10−9. A process was described which leads to the absolute minimum of nucleotide replacements required to account for the divergent descent of a set of genes given a particular topology for the tree depicting their ancestral relations. It was also shown that the convergent processes could realistically lead to amino acid sequences which would produce positive tests for relatedness, not only by a chemical criterion, but by a genetic (nucleotide sequence) criterion as well. Finally, a realistic case is indicated where truly homologous traits, behaving in a perfectly expectable way, may nevertheless lead to a ludicrous phylogeny.

Nomenclatural procedures in animal taxonomy, especially the application of priority rules in the vast entomological literature, are oppressively inefficient and becoming more so with the passage of time. The authors suggest that the problem be solved in a simple but radical way, by the device of officially recognizing selected monographs as the "new Linnaeus" of the group treated by the monograph. No publication prior to the monograph could then affect nomenclatural usage in the group, but a new monograph could supplant it.

Antitropical distributions of continental shelf, Indo-West Pacific species are probably not due to transgression of the tropics during the glacial periods, isothermic submergence, island integration, rising Neogene temperatures, or the Mesozoic dispersal of fragments from a Pacific continental mass. Characteristics of common antitropical patterns, plus information from systematic works on a variety of animal and plant groups, indicate that the long discarded “relict theory” of Théel (1885) appears to best fit the evidence, for it provides a mechanism whereby antitropical distributions may be brought about. The relict theory is compatible with the concept that the East Indies part of the Indo-West Pacific has been functioning as a center of evolutionary origin. It suggests that antitropical and associated disjunct patterns are produced as an older species, that has spread out to occupy a broad range, loses ground and gradually becomes supplanted by a younger species that had subsequently evolved in the East Indies. As this process goes on, the older species becomes restricted to a few isolated localities on the fringe of its original range. These isolates are often found to the north and south of the equatorial region but may include relict populations at the western edge of the Indian Ocean.

Louis Agassiz was under the false impression that the shells of brachiopods were lateral in position and that the group was related to mollusks. N. S. Shaler considered the shells to be anterior and posterior in position. E. S. Morse proved that the shells are dorsal and ventral, and showed that brachiopods form a distinct group somewhat related to tubicolous annelids. Journal records of Morse give historical sidelights which illuminate his controversy with Agassiz. Morse's classification of Brachiopoda became one of his principal contributions to zoology.

Schnell, Gary D. (Dept. Zoology, Univ. Oklahoma, Norman, Okla. 73069) 1970. A phenetic study of the suborder Lari (Aves)/II. Phenograms, discussion, and conclusions. Syst. Zool., 19:264–302 [Phenetics; numerical taxonomy; multivariate; Lari; cluster analysis].—Phenetic affinities of the 93 species of skuas, gulls, terns, and skimmers in the suborder Lari (Charadriiformes: Aves) are described in detail. Methods and materials, as well as the results of principal components analyses, were given in Part I (Schnell, 1970). In this paper the 18 phenograms resulting from the use of different character suites (51 skeletal, 72 external, and both combined), transformations, and clustering methods are presented and analyzed. A classification of these resulting classifications (clustering basic similarity matrices or cophenetic values on the basis of correlations between classifications) is used to indicate which methods and character suites give similar results. The phenograms have also been compared with the classifications of Peters (1934) and Moynihan (1959) for the Lari. For analyses that included suites of highly correlated characters, correlation matrices were found to be relatively more robust than distances, being affected less by transformations or the use of different character suites. Also, when particularly divergent classifications occurred, this was partly due to divergent basic similarity matrices, but the clustering procedures added additional differences. The placing (or forcing) of OTUs into a hierarchical system of clusters (rather than just analyzing basic similarity matrices) resulted in an indication of relationships between OTUs more in accord with the opinions of previous workers, who also represented relationships in a hierarchy. The determination of the “best” overall phenetic classification, for use when one is in need of a single measure of similarity, is discussed and a set of guides is suggested to aid in the selection of such a classification. Some cladistic speculations are given and the relative positioning and stability of clusters is discussed. When analyzing data with high correlations between characters, the use of adaptive hierarchical clustering schemes that take into account possible trends in variation found within clusters is strongly recommended, and the value of multiple classifications to represent affinities is stressed. Principal component models, where no assumption is made that OTUs must fall into clusters, were particularly useful in representing relationships. The analysis of external characters resulted in phenograms that showed some similarity to those based on skeletal measurements. However, there were significant differences, indicating support for only a weak version of the nonspecificity hypothesis. A morphological description, using numerous characters, should be particularly valuable to current and future workers conducting various types of comparative studies (e.g., behavioral, ecological) within this taxon. It seems obvious that accurate and detailed morphometric description at the interspecific level is as important in the sound development of evolutionary theory as quantitative studies of intraspecific (e.g., geographic) variation.

Immunologic analyses of serum proteins, studies of karyotypes, and morphology of spermatozoa reveal that vampire bats (family Desmodontidae) are more closely related to members of the family Phyllostomatidae than is suggested by conventional morphological characters. Immunologic tests show Desmodus to be related to the Phyllostomatidae through the subfamilies Phyllostomatinae and Glossophaginae. When fundamental and diploid numbers of chromosomes are plotted, two monotypic desmodontid genera (Desmodus and Diaemus) have karyotypic values that fall in the area of highest concentration of phyllostomatids. Spermatozoa of Desmodus and the third monotypic desmodontid genus, Diphylla, are indistinguishable in general morphology from those of representatives of five subfamilies of phyllostomatids. It is suggested that the vampires may represent only a subfamily of the Phyllostomatidae.

Geophysical maps depicting continental movement have consistently shown India, as it moved northward, to be located far out in the Tethys Sea. India split off from the African east coast about 148 m.y.a. From that time onward, according to almost all geophysical accounts, India was isolated from all other continents until the early Miocene when it made contact with Eurasia. But the biological data, both fossil and Recent, indicate that this concept cannot be correct. If India had really existed as an isolated, oceanic continent for about 100 m.y., it should have developed a peculiar biota with many endemic genera and families in its terrestrial and shallow marine habitats. But there are virtually no remains of organisms indicating that India was isolated for any substantial time (millions of years). Instead, we find that almost all Indian taxa were possessed in common with other continents. As time went on, the northern relationships became stronger and the southern ones weaker. Most of the recent geophysical accounts show India not making contact with Eurasia until the early Miocene, but fossil materials show that this event must have taken place by the early Eocene. It has been postulated that, as India moved northward, it created a biogeographic barrier that separated marine fish populations and resulted in the east-west provinces that are now apparent in the Indian Ocean. At the same time, the barrier effect was supposed to have resulted in the formation of sister species that are now located far apart. Information currently available indicates that most living, tropical marine species are probably not over 3 m.y. old. Consequently, the northward movement of India, which took place primarily between 148 and 50 m.y.a., could have no bearing on the relationships of modern species.

Inglis, W. Grant (South Australia Museum, Adelaide, Australia) 1970. The purpose and judgements of biological classifications. Syst. Zool., 19:240–250.—Biological classifications are judged by assessing their predictive value against the co-variance of character-states in organisms not previously studied or against the classification of some character-states not previously studied in the organisms classified. As a corollary, taxonomists, judging by their published work, aim to produce that classification which maximises the concordance of the classifications of single characters or, put another equivalent way, which maximises the character correlations of the organisms being classified. Such classifications are then assumed to be inductive and, therefore, predictive and this predictive content is tested. It is argued that the sole operational aim of taxonomy is the production of maximally concordant, and so predictive, classifications which can be explained by the fact of evolution. The reversal of this explanatory role wherein it is claimed that phylogenies can be studied by erecting such classifications has obscured rather than clarified discussion of classification. It is further argued that because all the characters in a given organism are not correlated some weighting of characters is inevitable in producing general classifications and that the taximetric approach has obscured the discussion of classification by erecting a series of axioms which make the testing of any classification depend upon the method by which it was constructed rather than upon the form of the classification itself.