摘要:

AbstractThe recently proposed biomechanical model of gastropod torsion (edlinger1988 a, b) is rejected on various reasons. First, the assumed original conditions in Polyplacophora and Tryblidiida as well as the constructed original condition in the Gastropoda do not emst in reality. Secondly, the mollus‐can musculature is a very dynamic structure (continuous assembly and disassembl) so that biomechanic rocesses are of much minor importance than assumed by Edlinger. Thirdly, the biomechanical model resented does not explain the change of the relative position of the lateral (= visceral) nerve cords which are surrounding the dorsoventral muscles in Polyplacophora and Tryblidiida (also Scaphopoda and Bivalvia), but are situated between the muscles in Cephalooda and Gastropoda. The consequences of these considerations to the early evolution of Gastropoda are briefly outline

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00432.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe composition, the hylogenesis and the sstematic arrangement of the family Calohypsibiidae are discussed. To this imil the generaCalohypsibius, Haplomacrobiotus, Parhexapodibius, Hexa‐podibiusandHaplohexapoibiusare to be ascried.Within the family two main hyletic lines can be distinguished. In one of them the diloclaws and the legs do not tend to be reduced (Calohypsibius), in the other the diploclaws and the legs have been affected by a more or less advanced and differentiated process of reduction. Within the latter ghyletic line two evolutionary trends can be distinguished; in the former the process of reduction as mostly affected the claws of the first three airs of legs where, by loss of the secondary branches, they have become single claws (Haplomacrobiotus). In the latter evolutionary trend the process of reduction has affected mostly the claws of the hind legs and, more or less, also the very legs.In the most primitive stem of this evolutionary trend the claws are dipclaws and they are present in all legs (Parhexapodibius). From the primitive stem a phyletic line as arisen in which the claws of the hind legs are quite lacking and the Kind legs are reduced to short stumps. This hyletic line is subdivided in two sister lines: in one of them the claws of the first three pairs of legs are reduced in size but maintain the secondary branches and they are then diloclaws (Hexapoditius), in the second phletic line the claws, by loss of the secondary branches, have become single claws (Haplohexapodibius). The systematic position ofApodibiusis discussed. Up to this time it is not absolutely sure that this genus is belonging to the family Calohypsibiida

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00433.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe aphid genusCrypromyzuswas studied using starch. el electrophoresis in order to establish differences between the various taxa and to estimate their paylogenetic relationships. A low degree of polymorphism and heterozyosity was observed. Taxa previously assumed to be homogeneous appeared to consist of different tost‐secific forms. Polymorphism at the PGI locus was used to assess the degree of isolation. It was founf to range from complete separation to a reduction in gene flow. Three methods of estimating hylogenetic relationships were employed: the UPGMA clustering method using Nei'sgenetic distance; the Rogersdistance together with the distance Wagnermethod and the independent allele model of Mickevichand Mitter(1981) combined with the Wagnerparsimony method. The results of all three methods agree that several of the taxa are closely related but assign different lower branching points to the phylogenetic tree. The independent allele model is discussed in more detail because it is not often applie

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00434.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractFurther studies about the amount of genetic load in the Korean Anyang and Cheju (Sughipo) Island populations ofDrosophila melanogasterwere performed. In total 1630 second chromosomes were extracted from the Anyang opulation between 1983 and 1985; 19.0 % of the chromosomes proved lethal, 8.8 % semilethal in homozygous condition. From the island oulation, 504 wild second chromosomes were analysed in 1986; 24.2 % were lethal, 4.6 % subleiaf A slight increase of lethal and semilethal frequencies between 1976 and 1986 can be observed. Mean viabilities of “all homozy‐gotes”, “quasinormal‐homozygotes”, and “random heterozygotes” were estimated from crossin experiments with marker strains. Random heterozygotes were always more viable than quasinormal homozygotes. An analysis for correlation between random heterozgous and homozygous viabilities gave values significantly different from zero only for the 1985 kyang sample (r =—0.4625, P<0.01), but no significances could be observed for all other Anyang samples from 1983, 1984, and 1986, respectively. he effective population sizes were estimated to be between 2000 and 6300 individuals for the Anyan and 4200 individuals for the island population, using Nel'sformula (1968). It is sugested that baknced natural selection is mainly responsible for the maintenance of genetic load in the Anyang natural populations

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00435.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractElectrophoretic variation of 13 presumptive enzymatic loci was studied in sticklebacks (Gasterosteus aculeatus) at 6 marine (Baltic) and 13 freshwater sites from Poland. Marine samples are significantly more variable (proportion of polymorphic loci, p # 0.38) than freshwater Samles (p # 0.12). Also the mean number of alleles per locus is significantly higher in the marine samples (n # 1.54) than in freshwater samples (n # 1.14). There is however no significant difference in values of mean heterozygosity between marine and freshwater sticklebacks. Some alleles are found in Baltic sticklebacks only, but all these occur in very low frequencies. Genetic distance between samples is low ranging from D = 0.000053 to 0.031410. However D is significant smaller between marine samples than between freshwater Samles. We suggest than this probaily is the result of larger genetic subdivision of freshwater populations. The low genetic divergence of marine and freshwater populations of the stickleback from poland might be expfained by the recent postglacial colonization of this area from a common refugium.

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00436.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractGenera with large numbers of species present particular difficulties; the analysis of relationships, of included taxa may be roblematic. One attempt to aproach this problem involves the reco of clusters of species tIat may be informally assembgd into species groups. The problems tE:g the recognition of such assemblages may induce are exlored. It is not that the species groups, as originail formulated, are problematic as they are initiafy erected to demarcate clusters withm an imperfectly known phylogeny of a supposedly monophyletic group. These species groups, however, tend to become recognized as “taxa” rather than operationaf clusters and as such tend to influence the approach to the inclusive taxon taken by subsequent workers. Rather than testing the concept of the species grous, there is a tendency to retain them and to insert other groups between them that do not exactly fit the original scheme. The establishment of species groups, first used to clarify a complex situation, has teen a source of problems for subseuent workers. The history of this aproach is traced for the gekkonid genusDiplodactylusand the problems that have arisen are outli

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00437.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractDemonstrated that in rodents the duration of ontogenetic development (from conception to the age of eye openin) is allometrically related to the maternal body weight. The differences between actual developmental time and the expected time (counted for animals of that systematic position and that body weight) can be used as a tool to test phylogenetic relationships. As far as the relationships between sister‐taxa are concerned, the results of the present analysis corroborate the conclusions of modern classifications. A long developmental time (which means by implication also a long pregnancy and precocity) is couled with hystricognathy and hystricomorhy. These traits must be considered plesiomorphic and their occurrence suggests conservatism of articular taxa. Parallell (coupled) with adopting sciurognathy and, particularly, protrogomorpiy, sciuromorphy, and eventually, myomorphy, rodents were able to shorten their developmental times. In this way they could increase the reproductive rate and made their reproduction more efficient. Consequently the respective taxa radiated more rapidly and successfull

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00438.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractRelative brain component sizes have been analyzed in subterranean mole rats of theSpalax ehren‐bergisuperspecies in Israel. Our results indicate that brain size and brain component sizes may have evolved in association with specific stresses underground involving the distinct development of vocalzation, olfaction and tactile sensory communication systems all compensating for the loss of visio

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00439.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAllozyme variation was studied the three living species ofLeiopelma. L. hamiltoniandL. archeyiare shown to be closely related to each other althoughL. hamiltoniis slightly more divergent relative toL. hochstetteri. This parallels previous cytoenetic data. The rarity and insularity ofL. hamiltonienables the calculation of a mutation rate based on genetic variance and population size. A mutation rate per generation of 2.7times 10‐‐6is sufficient to account for the observed levels of variation. Six populations ofL. hochstetterishow a pattern of genetic divergence that also closely parallels previously detected cytogenetic variation.L. hochstetteriis genetically distant from its congeneric species while all species ofLeiopelmaare at an extreme genetic distance fromAscaphus truei, the only other living amphicoelous fro At the limits of resolution of the allozme technique,Ascaphusclusters with the more morphologically advanced frogs,DiscogiossusandBombina, rather than withLeiopelma. Taken with other evidence, this supports recognition of two families, Leiopelmatidae anl Ascaphidae, withLeiopelmathe probable sister group of all other fr

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00440.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Ulenberg, SandrineA.: The systematics of the fig wasp parasites of the genus Apo‐crypta Coquerel.Dear, JamesP.: Fauna of New Zealand 8: Calliphoridae (Insecta: Diptera

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1989.tb00441.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY