Infaunal molting in Mid Paleozoic trilobites: new insights based on data from South America

RUSTÁN, J. J.; VACCARI, N.E:; BALSEIRO, D.

Bruselas

Simposio; IGCP596?SDS Symposium; 2015

Institut Royal des Sciences naturelles de Belgique

Infaunalism for molting in trilobites has been compellingly supported by a striking three-dimensional moltpattern, which was firstly reported from Late Silurian?Early Devonian phacopids of western Argentina(Rustán et al., 2011). The infaunal molt pattern (Fig. 1) is characterized by the thoracopygidium beingperfectly articulated, frequently exhibiting dorsal bending; the cephalon separated and located in front ordirectly above the first thoracic segments, trending to be overturned or perpendicularly oriented, and thehypostome dettached and displaced. Because no other taphonomic agent can be invoked for explaining thisdistinct spatial arrangement, it has been interpreted as biologically produced during molting, the trilobite beingentirely buried in soft sediment