摘要:

AbstractThe genus Bathydoris Bergh, 1884 (Gnathodoridacea) in the phylogenetic system of the Nudibranchia (Opisthobranchiu, Gastropoda)The position of the genusBathydorisBergh, 1884 in the phylogenetic system of the Nudibranchia is discussed.DoridoxaBergh, 1900, a genus which is assigned to the taxon Gnathodoridacea together with the genusBathydoris, is taken out from this taxon, lacking snapomorphies.Doridoxais considered to be a sister grou of the Euctenidiacea, with the transrormation of the right digestive gland into a caecum as the only synaomorphy with the latter. The Gnathodoridacea with the one enusBathydorisis removed from the taxon Doridacea and considered to be the sister group or the latter. Gnathodoridacea and Doridacea form the taxon Euctenidiacea with the synapomorphy “dorsomedial position of anus and nephroproct

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00350.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe sibling species of theEchinogammarus berilloni‐groupare endemic for the Iberian Peninsula and southern France. These species show wide morphological variability with some overlap in their dianostic characters making their distinction difficult. Reroductive isolation and enzmatic jivergence amon allopatric and sympatric populations of four species sharing the same chromosome number has been studied.The results show a clear genetic differentiation of E.longiserosusandE. calvusversus the other two species. However,E. margalefiandE. echinosetosusshow no clear genetic differentiation between them, confirming their crose relationship. All four species often coexist in the same drainage system. Isozme analysis was employed to check the hypothesis Of Margalefthat sympathy would occur age, long‐term phenomena of speciation inside of a given basin with subsequent contact and overlap between the differentiated forms. Electrophoretic data were also used to determine whether one flow among gammarids populations exists.A model proosed by other authors according to which the heterozyosity decreases towards the headwaters foes not fit to the data we have obtained fromE. calvus. Thus, populations of this species from sources and springs of the Duero basin show the hiFhest values of mean heterozygosity. The differentiation in this basin can be explained by drift. Migration between populations of different rivers is prevented by natural barriers. The lowest river stretches are without amhipods interrupting the gene flow amon populations.A correction between genetic and geographic fistances among subbasins and basins was found applying a double logarithmic model. A model of migration ofE. calvusin the Duero basin is proposed on the basis of allelic frequencies and on the distribution of mean hetero‐zygos

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00351.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThough the interweavement of trophic chains in marine ecosystems of the past cannot be reconstructed, as the abundance, nutrition, reproductive rates and other aspects of the biology of fossil species are not known, it is possible to correlate trends in the evolution of single groups of animals, in the presented case the Crustacea, with the influence of other evolving organisms. The evolution of carnivorous, buoyant, well swimming modern fishes probably induced profound changes in marine ecosystems and influenced the evolution of crustaceans. Indications for these interactions are a. the absence or rare occurrence of defenseless archaic crustaceans in habitats, which are populated by teleostean fishes and the survival of some of these forms in refuges like caves and subterranean waters, and b. the reduction of the pleon in the course of the mesozoic evolution of the Decapoda, which occurs parallel to the radiation of the Teleostei, namely in the period between the early Jurassic and the Tertiary. The shortening of the pleon is interreted as a consequence of the stepwise change from a hyperbenthic to a more benthic Iife‐stJe and the abandonment of the caridoid escape reaction. Other adaptations are also construed as results from the selective pressure produced by predators. Extant crustaceans which are able to coexist with fishes, among the macrozoobenthos especially the Decapoda and Peracarida, have a variety of protective adaptations, which help to reduce predatio

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00352.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe relationship between environmental factors, sex ratio and mating system inDaphnia magnawas examined, and the adaptiveness of environmental sex determination over ametic sex determination was explored. Monthly sexual sex ratios (males over total number of males and sexual females) ranged from 0.31 to 1.0, the three‐year average equalling 0.61. However, if only the samples collected during the period of frequent sexuality from August to October are included, the sexual sex ratio becomes equal, 0.51. Sexual sex ratios varied real between samples during the same period and the standard errors appeared highest in July ad August. Typical of suck times is some uncertainty in the environment, and the environmental cues can be contradictory. Sex expression inDaphniaappears to be determined by responses to complicated interactions between different environmental factors, which adaptively alter the sex ratio.The longterm sexual sex ratio ofDaphniaaproaching the equilibrium 1:1, despite environmental sex %termination, gives support for Fisier's classic theory of equal parental investment in both sexes. An equal sex ratio is advantageous also during periods of small population size because it maximizes the effective population siz

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00353.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractWe develop a fertility model of fitness that is general in that it does not assume that the fitnesses of the mating combinations are symmetrical or that they are additive or multilicative (i. e., that they can be inferred from fitnesses of the two genotypes involved in a mating). %he model considers one locus with three alleles. An experimental test withDrosophila rnelanogasterconfirms that the fitnesses of the mating types depart from both additivity (or multiplicativity) and symmetry although this last property is of no consequence for the development of analytical models). urnerical simulations yield the same, or very nearly the same, equilibrium freuencies as the analytical model, independently of whether or not Hardy‐Weinberg equilibrium Trequencies are assumed at the beginning of each selection cycl

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00354.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract1. Scanning electron microscop of the dentition of four anuran species (Discoglossus pictus, Bombina orientalis, Rana cyanophlyctis, Rana temporaria) revealed that at least the primary teeth, which are established during metamorphosis, are more or less bicuspid, bladed and nonpedicel‐late. Juveniles and adults, however, have pedicellate teeth.2. Thus, regardin the pedicellate condition, the sequence of stages in tooth development of Anura und Urodela show some similarities, although the primary teeth of urodeles develop already before metamorphosi

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00355.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractOn the systematic position of the amphisbaeniansThe hemipenis of amphisbaenians has scincomorph characteristics, e. g. plicae and microscopic spiny epithelium. In plesiomorph forms (Bipes, Blanus) the apex is simple, in apomorph forms (Trogonophis) it is forked.The genusAmphisbaenahas a variable hemipenis morphology. The species from the Antilles are clearly differentiated from those of the continent, the latter resembleLeposternonmore than their Caribbean congeners.The resemblance between hisbaenians and scincomorph lizards, especiall teiids, in mode of development of the orbitosplenoid (Bacbia:Bellairsand Gans1983) and in the mode of lung reduction (Bacbia:hoc loco) is congruent with resemblance in hemipenis characters. These resemblances are considered to be synapomorphic, not convergent.

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00356.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractChemosystematic investigations concerning the phylogeny of the collective genus Lacerta (Reptilia: Sauria: Lacertidae)Investigated the albumins from 31 species and subspecies of the genusLacertas.1. by means of the immunoloical techniue Micro‐Complement‐fixation. Dendrograms were computed by means of the ktch‐MargJiash algorithm. Moreover the taxa of theLacerta saxicolaand theLacerta danfordicomlexes were analyzed by electrophoresis concerning 14 genetic loci. The results were discussel together with karyological and genitalmorphological data so far known yielding the following relationships:Lacerta graecashows a closer relationshi to the subgenusPodarcisas does the quite closely related species airL. dugesiiandL. perspicikata. Lacerta Iaevisprobabl is connected closely toPodarcis, too.Lacerta parvashows a closer relationship to the “small izards” than to the sub‐genusLacerta s. str. A clear decision concerning the position of theLacerta danfordicomplex according to chemosystematical data was not possible. It is isolated from the other species probably about as long asL. puma. Biochemical differences between its “species” are too small to confirm their taxonomical revalorisation by Eiseltand SchmidtlerWithin theLacerta saxicolacomplex the investigated taxa show a close relationship.Lacerta praticolaandL. derjuginiwere definitly assigne

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00357.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Jerison, H. J.; Jerison, I. (eds.): Intelligence and evolutionary biology. Nato AS1 Series Ecological Sciences G 1Z Berlin, Heidelberg, New York, London, Paris, Tokyo, Hong KongLinser, H.: Dynamismus des Lebens. Aus dem Ereignis wird das Sein. Berlin und Hamburg.Fritzsch, B.; Ryan, M. J.; Wilczynski, W.; Hetherington, T. E.; Walkowiak, W. (Eds.).

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00358.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY