Mound with colonial corals, skeletal sponges and rudists.
Praeradiolites, Biradiolites.
Taxonomic data refer to paucispecific rudist lithosomes at Vilanoveta.

Abstract ref. 1703:
The late Cretaceous saw the sessile rudist bivalves reach maxima of adaptive  diversity and abundance on Tethyan carbonate platforms, yielding extensive 'rudist formations'. Meanwhile, reef frameworks built by corals were of notably limited development, although diverse associations of corals in tabular bedded units may accompany the rudist formations. The hypothesis of competitive displacement of reef- building corals  by rudists has sometimes been invoked to explain these patterns. An alternative view is that they reflect passive faunal replacement mediated by environmentally triggered extinctions, perhaps together with changes in carbonate platform ecosystems. The hypothesis of competition between contemporaneous organisms cannot be tested by looking at patterns of biotic turnover alone, as such patterns are the effects of many factors. What is needed is detailed palaeoecological analysis of co-occurrences of the postulated competitors. The Santonian carbonate platform deposits of Sant Corneli in the southern Central Pyrenees contain abundant and diverse corals, as well as rudists. A spectrum of biotic assemblages, from coral-dominated to rudist-dominated, is found to correspond with a sedimentary facies gradient expressed both in vertical successions and in a lateral zonation. The corals  and rudists largely occupied different biotopes, and even in mixed assemblages no evidence for competitive interference between neighbours (e.g. overgrowth relationships) has been detected. These observations imply little, if any, mutual interference between members of the two groups, in the occupation of space, while inferred nutritional differences between them allow us to reject trophic overlap. Similar distributional patterns reported for other Cretaceous assemblages lead us to conclude that there was probably little or no competition between rudists and corals, so undermining the competitive displacement hypothesis. We further dispute the underlying assumption that the rudists were occupying broadly the same kinds of habitats that hosted coral reefs at other times: the rudists usually thrived on flat to gently inclined mobile sediment surfaces, which we argue would have been unfavourable sites for reef development.

Coral to rudist transition in closed-by Vilanoveta.