Determinate growth is predominant and likely ancestral in squamate reptiles

Petra Frydlova*, Jana Mrzilkova, Martin Seremeta, Jan Kremen, Jan Dudak, Jan Zemlicka, Bernd Minnich, Kristina Kverkova, Pavel Nemec, Petr Zach, Daniel Frynta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Body growth is typically thought to be indeterminate in ectothermic vertebrates.
Indeed, until recently, this growth pattern was considered to be
ubiquitous in ectotherms. Our recent observations of a complete growth
plate cartilage (GPC) resorption, a reliable indicator of arrested skeletal
growth, in many species of lizards clearly reject the ubiquity of indeterminate
growth in reptiles and raise the question about the ancestral state of
the growth pattern. Using X-ray micro-computed tomography (μCT), here
we examined GPCs of long bones in three basally branching clades of squamate
reptiles, namely in Gekkota, Scincoidea and Lacertoidea. A complete
loss of GPC, indicating skeletal growth arrest, was the predominant finding.
Using a dataset of 164 species representing all major clades of lizards and the
tuataras, we traced the evolution of determinate growth on the phylogenetic
tree of Lepidosauria. The reconstruction of character states suggests that
determinate growth is ancestral for the squamate reptiles (Squamata) and
remains common in the majority of lizard lineages, while extended (potentially
indeterminate) adult growth evolved several times within squamates.
Although traditionally associated with endotherms, determinate growth is
coupled with ectothermy in this lineage. These findings combined with
existing literature suggest that determinate growth predominates in both
extant and extinct amniotes.
Original languageEnglish
Number of pages10
JournalProceedings of the Royal Society B
Volume2020
Issue number287: 20202737
Publication statusPublished - 23 Dec 2020

Fields of Science and Technology Classification 2012

  • 106 Biology

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