Synchrotron radiation X-ray tomographic microscopy (SRXTM) of brachiopod shell interiors for taxonomy: Preliminary report

Abstract

Synchrotron radiation X-ray tomographic microscopy (SRXTM) is a non-destructive technique for the investigation and visualization of the internal features of solid opaque objects, which allows reconstruction of a complete three-dimensional image of internal structures by recording of the differences in the effects on the passage of waves of energy reacting with those structures. Contrary to X-rays, produced in a conventional X-ray tube, the intense synchrotron light beams are sharply focused like a laser beam. We report encouraging results from the use of SRXTM for purely taxonomic purposes in brachiopods: an attempt to find a non-destructive and more efficient alternative to serial sectioning and several other methods of dissection together with the non-destructive method of X-ray computerised micro-tomography. Two brachiopod samples were investigated using SRXTM. In ?Rhynchonella? flustracea it was possible to visualise the 3D shape of the crura and dental plates. In Terebratulina imbricata it was possible to reveal the form of the brachidium. It is encouraging that we have obtained such promising results using SRXTM with our very first two fortuitous samples, which had respectively fine-grained limestone and marl as infilling sediment, in contrast to the discouraging results communicated to us by some colleagues who have tested specimens with such infillings using X-ray micro-tomography. In future the holotypes, rare museum specimens or delicate Recent material may be preferentially subjected to this mode of analysis.Sinhrotronska X-zracna tomografska mikroskopija (SRXTM) je nedestruktivna tehnika za proucavanje i sagledavanje unutrasnjih osobina kad cvrstih i neprozracnih objekata. Ona omogucava potpunu rekonstrukciju trodimenzijalnog izgleda unutrasnjih struktura na osnovu snimanja razlika u efektima energetskih zrakova kao reakcija na te strukture. Nasuprot X-zracima, proizvedenim u uobicajenoj X-zracnoj cevi, jaki sinhrotronski svetlosni snopovi su jasno fokusirani kao laserski snop. Prikazani su ohrabrujuci rezultati dobijeni upotrebom SRXTM za taksonomske svrhe kod brahiopoda: nacin da nadjemo nedestruktivnu i efikasniju zamenu serijskim presecima, nekih drugih metoda secenja kao i X-zracnoj kompjuterizovanoj mikro-tomografiji. Dve brahiopodske probe su proucavane pomocu SRXTM. Kod ?Rhynchonella? flustracea je bilo moguce sagledati 3D oblik krure i zubnih plocica, a kod Terebratulina imbricata dobili smo izgled brahidijuma. Nasuprot obeshrabrujucim rezultatima upotrebom X-zracne mikro-tomografije saopstenih od strane nekih kolega mi smo dobili pozitivne rezultate upotrebom SRXTM kod nase prve dve nasumicne probe na primercima zapunjenim finozrnim krecnjakom i laporcem. U buducnosti, holotipovi, retki muzejski primerci ili delikatan savremen materijal moci ce se proucavati na ovaj nacin.