SISTEMÁTICA E TAFONOMIA DOS CRUSTÁCEOS DECÁPODES DA ECOFÁCIES CAPANEMA DA FORMAÇÃO PIRABAS (MIOCENO INFERIOR), ESTADO DO PARÁ

Abstract

The systematic study of the decapod crustaceans of the Capanema ecofacies of the Pirabas formation (Lower Miocene), sampled in the B-17 deposit of the Cimentos do Brasil S/ACIBRASA, Capanema district, NE Para State, has confirmed the occurence of the Calappa circularis Beurlen, Acanthocarpus obscurus (Rathbun), Portunus haitensis Rathbun, Callinectes reticulatus Rathbun and Scylla costata Rathbun species. Also recognized are Portunus atecuicitilis Vega et al. , P. spinimanus Latreille, Necronectes tajinensis Vega et al. and Tetraxanthus rathbunae Chace, for the first time in Pirabas formation, and one undetermined species, Callinectes sp.1. The taphonomic study reveals that the fossiliferous concentration was formed by the only event, and that your burial occured in situ . The biostratinomic features suggest depositional environment with high energy during the burial event. The brachyura majority was buried after their death- normal position, although 45% represents specimens surprised by burial- escape position. The presence of the young and adults decapod suggest a event of high mortality, that implies in catastrophic event.