o:2501 Insular giant leporid matured later than predicted by scaling en The island syndrome describes morphological, behavioral, and life history traits that evolve in parallel in endemic insular organisms. A basic axiom of the island syndrome is that insular endemics slow down their pace of life. Although this is already confirmed for insular dwarfs, a slow life history in giants may not be adaptive, but merely a consequence of increasing body size. We tested this question in the fossil insular giant leporid Nuralagus rex. Using bone histology, we constructed both a continental extant taxon model derived from experimentally fluorochrome-labeled Lepus europaeus to calibrate life history events, and a growth model for the insular taxon. N. rex grew extremely slowly and delayed maturity well beyond predictions from continental phylogenetically corrected scaling models. Our results support the life history axiom of the island syndrome as generality for insular mammals, regardless of whether they have evolved into dwarfs or giants. Life-History Traits; Lepus-Europaeus; Bone-Histology; Reaction Norms; Large Mammals; Island Rule; Body-Size; Evolution; Age; Growth 1552099 10.1016/j.isci.2023.107654 2024-02-08T09:04:14.012Z 44 yes 46 Meike Köhler Universitat Autònoma de Barcelona Carmen Nacarino-Meneses Universitat Autònoma de Barcelona person Josep Quintana Cardona Universitat Autònoma de Barcelona person Walter Arnold-Ard University of Veterinary Medicine Vienna person 0000-0001-6785-5685 Gabrielle Stalder University of Veterinary Medicine Vienna person 0000-0002-8901-1181 Franz Suchentrunk University of Veterinary Medicine Vienna person 0000-0001-9862-5591 Salvador Moyà-Solà Universitat Autònoma de Barcelona person application/pdf 6829147 https://phaidra.vetmeduni.ac.at/o:2501 no yes 18 70 1552253 iScience 18 26 9 Cell Press 2023