Contribution
Bioclaustrations in Upper Ordovician bryozoans from northern Estonia
Vinn, Olev; Ernst, Andrej; Toom, Ursula
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 289 Heft 1 (2018), p. 113 - 121
publié: Jul 1, 2018
publication en ligne: Jul 5, 2018
ArtNo. ESP155028901003, Prix: 29.00 €
Abstract
Two new bioclaustrations, Anoigmaichnus zapalskii sp. nov. and A. bretti sp. nov., are described in Mesotrypa expressa colonies of Katian age. Both species were borings in the initial phase of growth and bioclaustrations in the later phase of growth. In addition, a new semiconical bioclaustration is described from Mesotrypa expressa. New data from the Late Ordovician of Baltica indicate that there may have been a peak in the diversity of bryozoan symbionts in the Ordovician. Late Ordovician trepostomes were especially prone for forming bioclaustrations around their soft bodied symbionts. There is great increase in diversity of bioclaustrations in the Late Ordovician which coincides with peaks in diversity of many Ordovician invertebrates. Diversity of bioclaustration ichnospecies is highest in colonial animals and bryozoans were the favoured hosts in the Ordovician.
Mots-clefs
traces • katian • baltica • bryozoans • bioclaustrations • symbiosis