Fossil barnacles from the Antarctic Peninsula: refining ways of exploring the nature of rare and/or delicate specimens employing X-ray Computer Tomography (CT)

Abstract

Assessment of unique and potentially significant fossils may be considerably compromised by surrounding matrix. This paper assesses a fossil barnacle group from the mid to late Eocene of Seymour Island, off the Antarctic Peninsula, that potentially has very significant phylogenetic importance. It discusses why the specimen could be significant, and describes and applies as a proof of concept an advanced imaging technique, using X-ray Computed Tomography (CT), that was effectively employed to confirm systematic taxonomy with virtual 3-D sections through the specimen. In this case, the Antarctic barnacle's complex internal plate morphologies were resolved by advanced 3-D imaging, such that a taxonomic attribution could be made to either the Archaeobalanidae or Austrobalanidae, excluding the initial assessment of Coronulidae, which would have otherwise been allusive.

An earliest Triassic age forTasmaniolimulusand comments on synchrotron tomography of Gondwanan horseshoe crabs

“…This precludes the need for physical dissection and/or preparation of specimens, which is relevant when describing structures from rare or fragile material ( e.g. , Metscher, 2009 ; Haszprunar et al, 2011 ; Deans et al, 2012 ; Beutel et al, 2019 ; Willsch et al, 2020 ; MacDougall et al, 2021 ; Stillwell et al, 2020 ). In palaeontology, 3D data has been used widely in the visualisation of fossils preserved in amber ( Lak et al, 2008 ; Perrichot et al, 2008 ; Riedel et al, 2012 ; Xing et al, 2016a ; Xing et al, 2016b ; Xing et al, 2018 ; Daza et al, 2020 ; Bolet et al, 2021 ) and also in the examination of fossils that are still surrounded in their original rock matrix ( Moreau et al, 2014 ; Schwarzhans et al, 2018 ; Reid et al, 2019 ; Mayr et al, 2020 ).…”