Evolution of WSC, WER, UWI and IZR in auguritids and pinacitids. Box plots of the evolution of whorl shape compression, whorl expansion rate, umbilical index and imprint zone rate through the phylogenetic sequence of the two studied ammonoid lineages, separately. Grey line indicates empirical evolutionary trend.
Monnet et al. BMC Evolutionary Biology 2011 11:115 doi:10.1186/1471-2148-11-115