Estimating the dwarfing rate of an extinct Sicilian elephant

• Published in: Current biology 2021-08, Vol.31 (16), p.3606-3612.e7
• Main Authors: Baleka, Sina, Herridge, Victoria L., Catalano, Giulio, Lister, Adrian M., Dickinson, Marc R., Di Patti, Carolina, Barlow, Axel, Penkman, Kirsty E.H., Hofreiter, Michael, Paijmans, Johanna L.A.
• Format: Article
• Language: English
• Subjects: ancient DNA; Animals; DNA, Ancient; DNA, Mitochondrial - genetics; dwarf elephants; Elephants - genetics; evolutionary rates; Extinction, Biological; Fossils; island evolution; mitochondrial DNA; Palaeoloxodon; Phylogeny; Sicily
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2021.05.037

Evolution on islands, together with the often extreme phenotypic changes associated with it, has attracted much interest from evolutionary biologists. However, measuring the rate of change of phenotypic traits of extinct animals can be challenging, in part due to the incompleteness of the fossil record. Here, we use combined molecular and fossil evidence to define the minimum and maximum rate of dwarfing in an extinct Mediterranean dwarf elephant from Puntali Cave (Sicily).1 Despite the challenges associated with recovering ancient DNA from warm climates,2 we successfully retrieved a mitogenome from a sample with an estimated age between 175,500 and 50,000 years. Our results suggest that this specific Sicilian elephant lineage evolved from one of the largest terrestrial mammals that ever lived3 to an island species weighing less than 20% of its original mass with an estimated mass reduction between 0.74 and 200.95 kg and height reduction between 0.15 and 41.49 mm per generation. We show that combining ancient DNA with paleontological and geochronological evidence can constrain the timing of phenotypic changes with greater accuracy than could be achieved using any source of evidence in isolation. •We present mitochondrial genome data from an extinct Mediterranean dwarf elephant•Dwarf elephant DNA diverged ∼0.4 million years ago from the large-bodied ancestor•Multidisciplinary evidence places a minimum and maximum boundary on dwarfing rate•We find a size reduction between 0.74 and 200.95 kg and 0.15 and 41.49 mm per generation Baleka et al. present mitochondrial genome data from an extinct Sicilian dwarf elephant, a small-bodied island lineage that evolved from one of the largest land mammals that ever lived. Combining the genetic data with geochronological and paleontological evidence, Baleka et al. provide an upper and lower estimate of the rate of island dwarfing.