DOI: 10.5061/dryad.hr718
title: Data from: Evolutionary origins of teeth in jawed vertebrates: conflicting data from acanthothoracid dental plates (‘Placodermi’)

description: Placoderms (Devonian fossil fishes) are resolved phylogenetically to the
 base of jawed vertebrates and provide important evidence for evolutionary
 origins of teeth, particularly with respect to the Arthrodira. The
 arthrodires represent a derived group of placoderms; the dentition of
 other more primitive placoderms such as the acanthothoracids is less well
 known. Articulated acanthothoracid dental plates are rare; x-ray computed
 tomography of a single, unique specimen, along with 3D segmentation of
 bone, oral denticles and vascular spaces, provides intrinsic developmental
 and topological information relevant to tooth origins. Recently, a
 disarticulated element was identified as a dental plate of the
 acanthothoracid Romundina stellina, with synchrotron microtomography
 providing characters to comment on ongoing debates regarding the evolution
 of teeth. We used segmental quantitative methods to re-analyse this data,
 for comparison to the articulated and unquestionable acanthothoracid
 dental plates above. We demonstrate substantial differences between these,
 disputing the identity of the isolated plate of R. stellina as a dental
 plate, and thus its relevance to questions of tooth evolution.
description: CPW.9A DG
 counterpart_01CT-scan. vol/vgi file
 may be opened in Amira or the program Drishti
 (http://anusf.anu.edu.au/Vizlab/drishti/).ZJ_CPW.9A_DG_counterpart_01.zipCPW.9A DG dentition_01CT-scan, Natural History Museum of the placoderm CPW.9A dentition. vol/vgi file may be opened in Amira or the program Drishti (http://anusf.anu.edu.au/Vizlab/drishti/).ZJ_CPW.9A_DG_dentition_01.zipCPW.9A ASG aboral surfaceAcanthothoraci (CPW.9A); 'Placodermi', Prince of Wales Island, Canada (Early Devonian, Lochkovian). Movie with virtual sections progressing anteroposteriorly, to show the flatter aboral surface of the ASG oral plate, and its connection to the ethmoidal region of the braincase.CPW.9A ASG vasculatureAcanthothoraci (CPW.9A); 'Placodermi', Prince of Wales Island, Canada (Early Devonian, Lochkovian). Movie showing oral denticles and associated vasculature (large blood vessels and capillary bed).Smith et al. Supplementary informationThis is a folder that includes two files: Smith_et_al._Supplementary_Information (doc) and Smith_et_al._Supplementary_Information (pdf). Description of CPW.9A and Fig. 1: Acanthothoraci (CPW.9A); ‘Placodermi’, Prince of Wales Island, Canada (Early Devonian, Lochkovian): A, dorsal view of PrM plate, showing stellate tubercles (tub.st), also flattened ones on ventral ‘lip’ (asterisk) and bifurcating ethmoidal commissure (ec). B, ventral view of PrM plate, ventral lip, with in situ articulated anterior supragnathal (ASG) dental plates, separated by junction between them and ventral lip of PrM; perichondral bone of ethmoid region of the braincase (eth). Scale bar represents 0.50 cm for both images.Smith_et_al_Supplementary_Information.zipTIFF stacksThis is a folder containing two subfolders holding TIFF stacks: 'ZJ_RomundinaDG' and 'ZJ_RomundinaDG_01'CPW.9A_Tiffs.zipCPW9 part + counterpartMovie from CT-scans of part and counterpart of CPW9