Intergrowth of bryozoans with other invertebrates in the Late Pridoli of Saaremaa, Estonia

Olev Vinn, Andrej Ernst, Mark A. Wilson, Ursula Toom

Abstract


Nine invertebrates intergrew with bryozoans in the latest Pridoli of Saaremaa, Estonia, namely: cornulitids (Cornulites baranovi and Conchicolites sp.), hydrozoans, rugosans (Tryplasma sp. and Entelophyllum sp.), Anoigmaichnus, microconchids (Tuberoconchus wilsoni), unknown tubicolous organisms and unknown soft-bodied organisms. The most common host of endobionts was Fistulipora przhidolensis, but trepostomes also participated in symbiotic associations. Solitary rugosan-cystoporate and hydrozoan-cystoporate associations were common in the Pridoli of Saaremaa, while other cases of intergrowth are rare. The rugosan-cystoporate, hydrozoan-cystoporate, hydrozoan-trepostome and Anoigmaichnus-cystoporate associations most likely were not a result of accidental intergrowth, whereas other associations presumably resulted from accidental intergrowth of two organisms. New data from the Pridoli of Saaremaa indicate that the Pridoli probably was not a time of lowered symbiosis levels in the regional ecosystem. Symbiosis levels in the Pridoli of Baltica were comparable to those in the Ludlow and Early Devonian worldwide.


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