Really Cool High Resolution 3D Reconstruction of Internal Structures of Paleozoic and Mesozoic Brachiopods

Knowledge of internal features of brachiopods is of critical importance for the accurate taxonomic study and identification of brachiopod taxa. To study the internal shell morphology of articulated brachiopod specimens, closely spaced serial sections are made using a WOKO 50P tomograph with section distances of 50 to 100 μm. In the past, two-dimensional acetate peels of serial-sections have been illustrated as drawings made from peels using a microscope-mounted camera lucida, or as photographs of polished sections of the actual specimens. This study presents a new method for generating detailed three-dimensional reconstructions of internal skeletal features of invertebrates (brachiopods) using the custom SPIERS software suited for registration, virtual preparation, and interactive visualization after digitization of acetate peels using a digital camera. To demonstrate the capabilities of the SPIERS software package, we show reconstructions of the internal skeletal structures of three Paleozoic and one Mesozoic brachiopod species. The software system generates detailed 3-D images of internal skeletal features such as dental plates, cardinalia (dental sockets, cardinal processes, etc.), and brachidial structures (spiriferid spiralia and terebratulid loops). Pairs of images generated by the SPIERS software can also be used to illustrate three-dimensional aspects of internal skeletal structures using split-screen or anaglyph stereo images. Paleozoic brachiopods shown are from Lower Devonian strata in Germany (Quiringites elegans), Morocco (Arduspirifer maroccanicus, Dixonella assaensis, Quiringites sp.), and South China (Rostrospirifer tonkinensis); the Mesozoic taxon is Monsardithyris sp. recently discovered in Jurassic strata from Jordan. The external shell features of species used as examples in this study are known from previous published studies, and their internal features shown using standard serial-section methods. This study is the first to perform three dimensional reconstructions of internal shell features of these taxa and we hope use of this and similar software systems becomes standard practice.