THALASSINOIDES AND ITS PRODUCER: POPULATIONS OF MECOCHIRUS BURIED WITHIN THEIR BURROW SYSTEMS, BOCA DO CHAPIM FORMATION (LOWER CRETACEOUS), PORTUGAL

Abstract This work describes the occurrence of numerous, nearly intact Mecochirus rapax populations within Thalassinoides suevicus burrows in the Lower Cretaceous Boca do Chapim Formation. This exceptional preservation allows for unquestionable attribution of a specific producer to a biogenic structure. Analysis of sedimentological features combined with functional morphology and ichnological inferences suggests that the unique preservation of the fauna resulted from river flood depositional events that buried successive Mecochirus populations in a shallow marine setting.