摘要:

An annotated list of the fishes collected by the Zaire River Expedition, October 1974 ‐January 1975, is presented, and five new species are described. The majority of the collections came from the River Lualaba and associated water bodies and provide new information on the distribution of die ichthyofauna in the Zaire basin. A re‐examination of the available geomorphological and zoogeographical evidence failed to substantiate the hypothesis that the upper Lualaba was formerly a tributary of the N

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01909.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The histology of developing toothplates ofNeoceratodusforsterifrom the time of first appearance of the tooth primordia to the adult condition has been investigated. The dentition develops by the formation of a shell of primary epithelial and mesenchymal matrices. Within the shell, secondary mesenchymal matrix and central material, both containing columns of tertiary matrix, are laid down. Primary epidielial matrix appears to contain collagen and is closely associated with the epithelium of the mouth. All other tooth tissues as well as the supporting bone develop in association with mesenchyme. Primary, secondary and tertiary mesenchymal matrices appear to contain collagen. Central dentine contains some fibres, possibly of reticulin or collagen, within a matrix of unknown composition.The tooth is attached to the underlying bone by a pedestal of bone and this grows with the tooth material.New tooth tissues are formed in the pulp cavity in layers below the older material, causing the toothplate to grow in every dimension as the animal grows.An evolutionary pathway is suggested for lungfish with a dentition of cusps arranged in radiating ridges.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01910.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The variability of characters used to segregate species in the taxonomically ‘difficult’ beetle genusAlticais briefly reviewed, based on examination of museum material from several sources and field samples of four species. Qualitative differences are compared with biometric data analysed using Student's (‐test and canonical variate analysis. Scanning electron micrographs of die ventral surface of the aedeagus of most species are given to aid identification. Biological species differences are reported including egg and larval characteristics, host plant specificity and reproductive behaviour. The cytology ofA. lythriis described for the first time. The difficulties of segregatingA. ericetiandA. britteni,the possible composite nature of A.oleracea,and species overlap betweenA. oleraceaandA. lythriare described. The taxonomic problems posed by the genus are discussed widi reference to parthenogenesis and sibling species.SummarySeveral morphological characters used to segregate species within the chrysomelid beetle genusAlticaare unreliable because of intraspecific variation. The aedeagus of the male is the most reliable feature but some speciesappearto show parthenogenetic reproduction at certain times. Host plant, egg characteristics and oviposition behaviour are useful aids to identification. Biometrics is helpful in the segregation of natural populations but of limited use when dealing with individual specimens of unknown origin. The genus may contain sibling species not yet recog

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01911.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY