Santos et al., 2015

Author(s):Santos, A., Mayoral, E., Dumont, C., da Silva, C., Ávila, S., Baarli, B. G., Cachão, M., Johnson, M., Ramalho, R.
Year:2015
Title:Role of environmental change in rock-boring echinoid trace fossils
Journal:Palaeogeography, Palaeoclimatology, Palaeoecology
Volume:432
Pages:1-14
Abstract

Well preserved groove-borings related to the boring activity of regular sea urchins are preserved on Neogene rocks associated with rocky palaeoshores in a volcanic oceanic island (Santa Maria, Azores archipelago) and a continental margin (Foz da Fonte, Central West Portugal). The new trace fossilconsists ofa series of relatively deep grooves, with sinuous pathwayand with a fairly uniform width along its trajectory. A series of forward oriented concave markings occur frequently inside the grooves, reflecting the movement direction of the producer. The trace fossil is designated as Ericichnus igen. n. with two new ichnospecies, Ericichnus bromleyi isp. n.and Ericichnus asgaardi isp. n. Ericichnus igen. n. could have been produced by regular echinoids, similar to the extant echinometrid echinoid Echinometra lucunter (Linnaeus, 1758) for E. bromleyi isp. n. and similar to the echinid Paracentrotus lividus Lamarck, 1816 for E. asgaardi isp. n. Ethologically, the compound trace fossil Ericichnus igen. n. - Circolites may correspond to an agrichnion – pascichnion and/or domichnion. Our study suggests that the new ichnospecies E. bromleyi may be used as a palaeoenvironmental tool, indicating the boring activity of termophile rock-boring echinoids in the fossil record.

Keywords:Bioerosion, Echinoidea, New ichnotaxon, Paleontology, Portugal, Rocky shore, Trace fossils, Tracemaker
DOI:https://doi.org/10.1016/j.palaeo.2015.04.029
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