ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00109.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

This paper is a review of published information on fossil lobopodians, with addition of observations and ideas based on new material. It is also an analysis of the phytogeny of the group, and presents a new classification. A character shared by three or four families, yet not seen before, is a pair of enlarged sclerites covering the head. This forms an argument for re‐orientingHallucigeniaonce again. This genus no longer being enigmatic, a corner‐stone in Stephen Jay Gould's evidence for extinct phyla is therefore gone. It is suggested that the lobopodians, phylum Lobopodia, are arranged in two classes, the extinct Xenusia for marine forms, and the Onychophora for terrestrial forms. The marine lobopodians are morphologically much more diverse than the extant onychophorans, a condition expressed in the classification. New taxa are:Hallucigenia fortissp. nov., the families Luolishaniidae, Cardiodictyidae and Onychodictyidae, and the new orders Archonychophora, Scleronychophora and Paronychoph

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00110.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A cladistic analysis places the Onychophora between Polychaeta and Arthropoda. The ‘Uniramia‘concept is not supported. No justification was found for either onychophoran family to be considered ancestral. A cladogram of fossil genera indicates the common ancestor to have long oncopods, armoured plates and an annulated body. Later forms show adaptations to life in reduced spaces. Physiological data suggest that the Onychophora became adapted to land via the littoral zone, before the Late Ordovician. Adhesive glands evolved for defence on land. Peripatopsidae and Peripatidae were distinct by the late Triassic. The occurrence of onychophorans probably datesfrompost‐Pliocene in New Guinea and southern Australia, and post‐Early Cretaceous in Chile, the southern half of Southeast Asia, Mesoamerica and the Caribbean. After the Early Cretaceous, the peripatids of tropical Africa lost terrestrial contact with those of South America. A new biogeographic technique, formalized here under the name retrovicariance, indicates that the Peripatidae of Equatorial Africa and the Neotropics are sister‐groups. Typical inbreeding adaptations found in some onychophorans include: female‐biased sex ratios; gregarious development; relatively constant time of development and number of offspring in each clutch; male polygamy and shorter life span; frequent sibmating in the microhabitat of development, and sperm storage by females, so that a single insemination fertili

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00111.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

During embryonic development the process of segment formation in both families of the Onychophora, the Peripatidae and the Peripatopsidae, follows an essentially similar pattern with the exception of the South African peripatopsid,Opisthopatus cinctipesPurcell. In all other species in which development has been described, paired lateral halves of the embryo, separated by extra‐embryonic ectoderm, develop as thickened bands on the surface of the blastoderm coincident with the appearance of the mouth and anus. The bands quickly differentiate paired segmental swellings with intersegmental grooves. The body elongates by proliferation from a posterior growth zone. During this process, presumptive mesoderm, located posteriorly in the early embryo, proliferates and moves anteriorly to form two lateral bands of mesodermal cells which segment during their forward growth into an anterior‐posterior sequence of paired somites. InO. cinctipesthe embryo elongates without any visible external or internal segment boundaries. In the elongating embryo only ectoderm and endoderm layers are present. Only after elongation has occurred are mesodermal somites formed. Allozyme analysis indicates thatO. cinctipesdiverged from the other South African genusPeripatopsisPocock, with in the last 30

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00112.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The rationale of promoting onychophorans as target taxa in invertebrate conservation is discussed. Current knowledge relevant to onychophoran conservation is outlined and gaps are identified. The prospects for conserving onychophorans are discussed, and priorities suggested.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00113.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Allozyme electrophoresis has been employed to examine genetic differentiation among eight described species, and representatives of an additional 15 taxa, of Australian peripatopsid Onychophora. The data reveal extremely high genetic differentiation among the described species and among the other taxa, each of which warrants specific recognition. Rapid protein evolution cannot account for the large genetic distances and it is proposed that these are a consequence of ancient divergence times. A method is presented for extracting phylogenetic information from allozyme data sets which are not amenable to conventional analysis.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00114.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Specimens of peripatopsid Onychophora from New Zealand (the viviparousPeripatoid.es novaezealandiaeandP. suteriand the oviparousOoperipatellus insignis)have been analysed by allozyme electrophoresis and compared with three species of viviparous peripatus and0. insignisfrom Australia. The data indicate that at least two species ofPeripatoidesare present, in addition to those described. Populations collected from Dunedin, in the South Island, are not referable on morphological grounds to any described genus. Furthermore, specimens exhibit such a high level of genetic distinctiveness that we speculate they have diverged from thePeripatoidesandEuperipatoideslineages prior to the separation of Australia and New Zealand some 95 Myr ago. Specimens referable to0. insignisfrom New Zealand are genetically quite distinct from0. insignisat its type locality in Australia and must be considered endemic.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00115.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Variation within and between populations ofCephalofovea(Peripatopsidae) has been examined by allozyme, karyological and morphological analyses. Four groups are recognized on the basis of allozyme electrophoresis. One group includes specimens from the type locality of the only described species of the genus,C. tomahmontis.While karyotypic and morphological character states show considerable inter‐group variation, the distributions of these states among groups are not concordant when different characters are compared. However, each group of populations is uniquely defined by the full suite of character states it possesses. The four groups are recognized here as distinct species with three species described as ne

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00116.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A chromosomal analysis of populations of viviparous Australian onychophorans has uncovered a large radiation in karyotypic form. Chromosome numbers of 18, 26, 30, 32, 33 and 34 were observed, and these classes could be further subdivided on the basis of internal size relationships. Given the practical difficulties with the systematics of this group, the use of chromosomal data promises to be particularly enlightening. This is the first time any karyotypic data have been published for onychophorans since a single species was analysed in 1900.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00117.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb00109a.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY