Morphometric analysis of lungfish endocasts elucidates early dipnoan palaeoneurological evolution

Griphognathus whitei (NHMUK PV P 56034) was scanned at the Natural History Museum, UK, using a Nikon Metrology HMX ST 225 micro-CT scanner. The specimen was scanned with the following parameters: Energy 210 KeV, voxel size 102 microns, 180 degrees, 3142 proj, angle step 0.1 deg/proj, exposure time 0.5 sec/proj, object to detector 1170 mm (filters: 2.5 mm Cu). The resulting image stack was rendered and segmented manually using Drishti and Drishti Paint 2.6.1 to produce a virtual 3D endocast. Orlovichthys limnatis (PIN (3725/110) was scanned at the Palaeontological Institute, Moscow, in three sections using a Skyscan 1172 micro-CT scanner. Each section was scanned with the following parameters: Energy 100 KeV, voxel size 34.1 microns, 180 degrees, 514 proj, angle step 0.7 deg/proj, exposure time 0.79 sec/proj, object to detector 344 mm (filters: 1 mm Al). The resulting image stacks of all specimens were combined using ImageJ and the subsequent image stack was rendered and segmented manually using Drishti and Drishti Paint 2.6.1 to produce a virtual 3D endocast.