Fig. 1 Whatcheeria deltae is an early diverging Carboniferous stem tetrapod. a Known from the latest Viséan–earliest Serpukhovian (331–326 Ma) Jasper Hiemstra Quarry of Iowa, USA (b). Our sample includes a range of known size classes of Whatcheeria femora, a selection of which are figured here (c). From left to right the specimens include size class I (FMNH PR 5021), size class II (FMNH PR 1962), size class III (FMNH PR 1958), and size class IV (FMNH PR 5023). Scale bar for skeletal reconstruction = 10 cm and femora specimens = 1 cm. Global map is modified from the PaleoBio Database and Ichthyostega silhouette was drawn by SEP, while others were sourced from PhyloPic.

Published as part of Whitney, Megan R., Otoo, Benjamin K. A., Angielczyk, Kenneth D. & Pierce, Stephanie E., 2022, Fossil bone histology reveals ancient origins for rapid juvenile growth in tetrapods, pp. 1-9 in Communications Biology 5 (1) on page 3, DOI: 10.1038/s42003-022-04079-0, http://zenodo.org/record/7390744