Nom du corpus

Corpus Systématique Animale

Titre du document

Fine structure and formation of eggshells in marine Gastrotricha

Lien vers le document
Éditeur
Springer (journals)
Langue(s) du document
Anglais
Type de document
Research-article
Nom du fichier dans la ressource
Vers_v2b_00168
Auteur(s)
  • Gunde E. Rieger 1
  • Reinhard M. Rieger 2
Affiliation(s)
  • 1) Curriculum of Marine Sciences, University of North Carolina, 27514, Chapel Hill, NC, USA
  • 2) Department of Zoology, University of North Carolina, 27514, Chapel Hill, NC, USA
Résumé

The fine structure of the gastrotrich eggshell in the hermaphroditic species Turbanella ocellata (Hummon 1974) and the parthenogenetic species Aspidiophorus sp. is described using transmission electron microscopy. The presented evidence strongly suggests that the shell is produced by the egg itself prior to oviposition in both species. The layed egg in Aspidiophorus sp. is provided with a special attachment stalk that is also preformed in the mother animal. Freshly layed eggs of T. ocellata are adhesive all around their surface and lack any specialized structures for attachment. Formation of the spiny eggshell of Aspidiophorus sp. appears to begin with a sudden release of special vesicles containing the preformed spines of the outer eggshell covering. Additional material appears to be secreted by the egg in a more gradual process after the initial vesicle release. The formation of the two fibrous layers in the eggshell of T. ocellata is less well understood and deposition of eggshell material could be seen either as a continuous process or as two separate steps, similar to the events observed for Aspidiophorus sp. For T. ocellata, Tetranchyroderma sp. and Aspidiophorus sp. it is demonstrated that formation of the cuticle occurs as an independent process from that of eggshell formation. This is significantly different from the basic mode of cuticle formation in the annelid line of evolution. The paper argues further that the data support earlier claims of a pronounced difference between the Gastrotricha-Macrodasyida and the Gastrotricha-Paucitubulatina and agree well with the postulated ties of the Gastrotricha and Nematoda. The phylogenetic importance of the eggshell fine-structure is discussed in the framework of present theories on aschelminth phylogeny.

Catégories Science-Metrix
  • 1 - natural sciences
  • 2 - biology
  • 3 - evolutionary biology
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
  • 4 - invertebres
Catégories Scopus
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Developmental Biology
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Animal Science and Zoology
Catégories WoS
  • 1 - science ; 2 - zoology
  • 1 - science ; 2 - anatomy & morphology
Identifiant ISTEX
790D22EA66BB63F320DAF855CC7FF3AF899980CA
Revue

Zoomorphology

Année de publication
1980
Présence de XML structuré
Non
Version PDF
1.3
Score qualité du texte
10
Sous-corpus
  • Vers
Type de publication
Journal
ark:/67375/1BB-4MF27FZ0-M
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