Give me hard substrates! Biotic interactions between Danian serpulids and oysters from Patagonia

BREZINA, S.; ROMERO, M. V.; CASADIO, SILVIO

General Roca

Congreso; 11 Congreso de la Asociación Paleontológica Argentina; 2016

Asociación Paleontologica Argentina

Many works on recent and fossil oysters as hard substrates have shown characteristicdistribution patterns of sclerobiotic assemblages and also biotic relationships ascommensalism, parasitism, overgrowth, among others. This information can be useful toreconstruct life habits of extinct fossil organisms and biotic interactions if they were infestedduring their lifetime. The aim of this work is to assess possible paleoecological relationshipsamong serpulid worms and Pycnodonte (Phygrea) burckhrdti (Böhm, 1903), an early danianoyster included in mudstones beds of Jagüel Formation, in General Roca locality. A total of189 oysters were analyzed (60 left, 24 right, and 115 articulated specimens) and the presence/absence of serpulids on the valves were registered. Statistical analysis (i.e., goodness of fittest and exact confidence intervals for the binomial distribution) were performed in order toassess possible preference of serpulids for different areas of the valves. Results showed adifferential settlement of tube worms in the external margins of both valves. These uncoveredareas could have placed a few milimeters above the sediment-water