The nature and mode of life of the graptolite zooid with reference to secretion of the cortex

• Autorzy: Crowther P.R.
• Języki publikacji: EN

Abstrakty

EN

Scanning electron microscope studies of well preserved, isolated graptolites have revealed a radically new and unexpected structure to both normal cortex and endocortex, termed here "cortical bandaging". Bandage structure is described and illustrated for several species and the collagenous nature of the component fibrils confirmed. The evidence presented sheds new light on the nature of the graptolite zooid and how it functioned, in particular on the mode of skeletal secretion. A model involving a more pterebranch-like zooid is preferred to the recent idea of Urbanek (1976) and Kirk (1972) for secretion beneath a perithecal membrane.

• Wydawca: -
• Czasopismo: Acta Palaeontologica Polonica
• Rocznik: 1978
• Tom: 23
• Numer: 4
• Opis fizyczny: p.473-479,ref.

Twórcy

autor

Crowther P.R.

• Department of Geology, Sedgwick Museum, Downing Street, Cambridge CB2 3EQ, U.K.

Bibliografia

• ANDRES, D. 1977. Graptolithen aus ordovischen Geschieben und die frühe Stammesgeschichte der Graptolithen. - Paläont. Z, 51, 52-93.
• BULMAN, O.M.B. 1932. On the graptolites prepared by Holm. I. Certain "Diprionidian" graptolites and their development. - Ark. Zool., 24A, 8, 1-46.
• CROWTHER, P.R. and RICKARDS, R. B. 1977. Cortical bandages and the graptolite zooid. - Geol. Palaeont., 11.
• DILLY, P.N. 1976. Some features of the ultrastructure of the coenicium of Rhabdopleura compacta. - Cell Tiss. Res., 170, 253-61.
• KIRK, N.H. 1972. Some thoughts on the construction of the rhabdosome in the Graptolithina, with special reference to extra-thecal tissue and its bearing on the theory of automobility. - Univ. Coll. Wales, Aberystwyth, Dept. Geol. Publ., 1, 1-21.
• KOZŁOWSKI, R. 1949. Les graptholites et quelque nouveaux groupes d'animaux du Tremadoc de la Pologne. - Palaeont. Pol., 3, 1-235.
• URBANEK, A. 1976. The problem of graptolite affinities in the light of ultrastructural studies on peridermal derivatives in pterobranchs. - Acta Palaeont. Pol., 21, 3-36.
• - and TOWE, K.M. 1974. Ultrastructural studies on graptolites. I. Periderm and its derivatives in Dendroidea and Mastigograptus. - Smiths. Contr. Paleobiology, 20, 1-48.
• - and - 1975. Ultrastructural studies on graptolites. II. The periderm and its derivatives in Graptoloidea. - Ibidem, 22, 1-48.