IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
CRUSTACEAN ICHNOLOGY IN MARINE ENVIRONMENTS: AN UPDATE
Autor/es:
CARMONA, N.B.; BUATOIS, L.A.; MÁNGANO, M.G.
Lugar:
Huelva, España
Reunión:
Workshop; Workshop on Crustacean Bioturbation – Fossil and Recent; 2010
Resumen:
Crustaceans are among the most important burrowers in the marine realm, occurring from supratidal areas to deep-marine settings. Trace fossils assigned to the activity of decapod crustaceans are well known from the ichnologic record. Several ichnotaxa have been defined, being Ophiomorpha, Thalassinoides and Spongeliomorpha the most common ichnogenera. Additional ichnotaxa (i.e. Gyrolithes, Pholeus, Macanopsis, Psilonichnus and Sinusichnus, among others) are also interpreted as crustacean burrows, although they seem to be less common. Parallel to ichnotaxonomic studies, a number of recent studies have focused on the paleoenvironmental significance of these decapod burrows. The known ethological plasticity of these crustaceans (being adapted to live in a wide variety of environments) is also reflected in their extensive ichnologic record. The ichnofossils mostly occur in softground suites developed in shallow-marine settings, although they are also distinctive components of firmground suites and in deep-marine deposits. Additionally, the temporal pattern of distribution of decapod-like burrow systems through the Phanerozoic has been recently explored to unravel evolutionary trends and to compare the trace- and body-fossil records. The Paleozoic records of burrow systems are sparse and difficult to interpret in terms of producers. The presence of burrow systems (i.e. Thalassinoides) in Early Paleozoic rocks most probably records burrowing by groups other than decapod crustaceans, therefore reflecting behavioral convergence. Post-Paleozoic records are more confidently attributed to decapods, and the slow rise in the abundance of these structures through the Mesozoic shows a good correlation with the trends inferred from the body-fossil record. During the Palaeogene, the number of decapod ichnofossils reported is considerably lower than that for the Cretaceous, probably reflecting the effect of the end-Cretaceous mass extinction and/or monographic effects. During the Neogene, the abundance of decapod trace fossils underwent a remarkable increase, and crustacean burrows became dominant elements of shallow-marine ichnofaunas, commonly being part of communities displaying complex endobenthic tiering patterns. Recognition and analysis of these crustacean ichnotaxa, together with the understanding of their paleoecologic and evolutionary significance is essential to characterize marine ichnofaunas, particularly those established after the Mesozoic Marine Revolution.