摘要:

Abstract—This paper reports results from a cladistic analysis of the 11 Recent arachnid orders. The polarities of 64 newly discovered and traditional characters were determined through outgroup comparisons that included Eurypterida, Xiphosura, Trilobita and Crustacea. A branch‐and‐bound algorithm was used to discover a single tree (consistency index 0–59). The relationships suggested by this analysis differ substantially from previous interpretations of arachnid phylogeny, and a new taxonomic system is introduced to accommodate these results. This analysis suggests that Arachnida is monophyletic and composed of two principal lineages, Micrura and Dromopoda. Possible synapomorphies of Micrura include a pygidmm, tntosternum, six principal lateral eyes, poorly sclerotized postgenital appendages, coxal gland orifices near leg 1, an array of micxotubules associated with the spermatozoan nucleus, and absence of coxal endites on the walking legs. The micruran orders appear to have the following relationships: (Palpigradi (Araneae (Amblypygi (I helyphonida, Schizomida)))) (Ricinulei, Acari). Possible synapomorphies of Dromopoda include transverse carapaeal furrows, greatly reduced prosomal sternum, prosomal endosternite with two segmental components, stomotheca, bicondylar femoropatellar and patellotibial joints and extensor muscles. The dromopodan orders appear to have the following relationships: Opiliones (Scorpioncs (Pscudo‐scorpiones, So

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00523.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Abstract—A species' habitat preference is intcrpretablc both as a response to present‐day conditions and as a result of evolutionary response to historical conditions. The taxon cycle and taxon pulse have been proposed as hypotheses that allow prediction of patterns of habitat specialization within a lineage. Both are based on common assumptions: (1) habitat specialization is largely irreversible in a lineage, (2) ecological specializations arise in a center of origin, and (3) dispersal events leading to current distributions can be ascertained. Eight taxa of Antillean, Mexican, and Central American Carabidae, for which cladistic hypotheses of relationship have been proposed, are used to test the generality of the taxon cycle and pulse. The patterns of habitat utilization predicted by the taxon cycle and taxon pulse hypotheses are tested by comparing cladistic transformations of habitat preference to randomly generated patterns of data generated under a null hypothesis. Evolutionary changes in habitat are interpreted using Camin‐Sokal coding, which assumes irreversible habitat shifts and a predetermined ecological ground state (assumptions of the taxon cycle and taxon pulse). An observed pattern is considered to demonstrate the taxon cycle or pulse when it results in an explanation of the habitat shifts that is more parsimonious than 95 % of the randomly generated patterns. Of the eight carabid groups, only one exhibits a statistically significant pattern supporting the taxon cycle and pulse. The failure of the taxon cycle and pulse as generally predictive hypotheses may be due to historical changes in climate that permit episodes of range expansion for species previously restricted to small ranges, and habitat shifts and specialization that do not progress in a linear transformation series.Habitat shifts are also analyzed using Farris optimization, resulting in the most parsimonious transformation series of habitats, subject to a predefined ordering of habitats, while allowing reversals. Significance of an observed pattern of habitat shifts under Farris optimization implies habitat constancy relative to cladogenesis, and step‐wise changes in habitat preference. Two of the eight groups exhibit significant patterns of habitat utilization under Farris optimization, indicating that vicariance of areas of like habitat has been the predominant factor generating species diversity in these groups. The other groups do not exhibit habitat constancy, suggesting rapid changes in habitat preference relative to spe

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00524.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00525.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00526.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00527.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00528.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00529.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Book reviewed in this article:Oxford Surveys in Evolutionary Biology, Volume 3.—R. Dawkins and M. Ridley (eds).Oxford Surveys in Evolutionary Biology: Volume 3.—R. Dawkins and M. Ridley (e

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00530.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1990.tb00531.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY