Molecular exploration of fossil eggshell uncovers hidden lineage of giant extinct bird

Alicia Grealy; Gifford H Miller; Matthew J Phillips; Simon J Clarke; Marilyn Fogel; Diana Patalwala; Paul Rigby; Alysia Hubbard; Beatrice Demarchi; Matthew Collins; Meaghan Mackie; Jorune Sakalauskaite; Josefin Stiller; Julia A Clarke; Lucas J Legendre; Kristina Douglass; James Hansford; James Haile; Michael Bunce

doi:10.1038/s41467-023-36405-3

Molecular exploration of fossil eggshell uncovers hidden lineage of giant extinct bird

Nat Commun. 2023 Feb 28;14(1):914. doi: 10.1038/s41467-023-36405-3.

Authors

Alicia Grealy^{1

2}, Gifford H Miller³, Matthew J Phillips⁴, Simon J Clarke⁵, Marilyn Fogel⁶, Diana Patalwala^{7

8}, Paul Rigby⁷, Alysia Hubbard⁷, Beatrice Demarchi⁹, Matthew Collins^{10

11}, Meaghan Mackie^{10

12}, Jorune Sakalauskaite^{9

10}, Josefin Stiller¹³, Julia A Clarke¹⁴, Lucas J Legendre¹⁴, Kristina Douglass¹⁵, James Hansford^{16

17

18}, James Haile¹⁹, Michael Bunce²⁰

Affiliations

¹ Trace and Environmental DNA (TrEnD) Laboratory, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia. alicia.grealy@uqconnect.edu.au.
² The Australian National Herbarium, CSIRO, Bldg 502 Clunies Ross Street, Acton, ACT, 2601, Australia. alicia.grealy@uqconnect.edu.au.
³ INSTAAR and the Department of Geological Sciences, University of Colorado, Boulder, CO, 80309, USA. gmiller@colorado.edu.
⁴ Vertebrate Evolution Group, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD 4000, Australia.
⁵ Integrity Ag & Environment, 10511 New England Highway, Highfields, QLD 4352, Australia.
⁶ EDGE Institute, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA.
⁷ Centre for Microscopy, Characterisation and Analysis, Harry Perkins Institute of Medical Research, The University of Western Australia, Crawley, WA, 6009, Australia.
⁸ National Imaging Facility, University of Western Australia, Crawley, WA, 6009, Australia.
⁹ Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina, 13, 10123, Torino, Italy.
¹⁰ The Globe Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Oster Farimagsgade 5, Bygning 7.101, 1353, Copenhagen, Denmark.
¹¹ McDonald Institute for Archaeological Research, University of Cambridge, 2.4 West Tower, Downing St, Cambridge, CB2 3ER, UK.
¹² Novo Nordisk Foundation Center for Protein Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 6.2, 2200, Copenhagen, Denmark.
¹³ Villum Centre for Biodiversity Genomics, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark.
¹⁴ Department of Geological Sciences, The University of Texas at Austin, 2275 Speedway Stop C9000, Austin, TX, 78712, USA.
¹⁵ The Climate School, Columbia University, New York, NY, 10025, USA.
¹⁶ Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK.
¹⁷ Department of Biological Sciences, Northern Illinois University, DeKalb, IL, USA.
¹⁸ Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, UK.
¹⁹ Research Laboratory for Archaeology and the History of Art, Oxford University, Oxford, OX12JD, UK.
²⁰ Trace and Environmental DNA (TrEnD) Laboratory, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia.

Abstract

The systematics of Madagascar's extinct elephant birds remains controversial due to large gaps in the fossil record and poor biomolecular preservation of skeletal specimens. Here, a molecular analysis of 1000-year-old fossil eggshells provides the first description of elephant bird phylogeography and offers insight into the ecology and evolution of these flightless giants. Mitochondrial genomes from across Madagascar reveal genetic variation that is correlated with eggshell morphology, stable isotope composition, and geographic distribution. The elephant bird crown is dated to ca. 30 Mya, when Madagascar is estimated to have become less arid as it moved northward. High levels of between-clade genetic variation support reclassifying Mullerornis into a separate family. Low levels of within-clade genetic variation suggest there were only two elephant bird genera existing in southern Madagascar during the Holocene. However, we find an eggshell collection from Madagascar's far north that represents a unique lineage of Aepyornis. Furthermore, divergence within Aepyornis coincides with the aridification of Madagascar during the early Pleistocene ca. 1.5 Ma, and is consistent with the fragmentation of populations in the highlands driving diversification and the evolution of extreme gigantism over shorts timescales. We advocate for a revision of their taxonomy that integrates palaeogenomic and palaeoecological perspectives.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Birds* / classification
Egg Shell*
Extinction, Biological
Fossils*

Associated data

Dryad/10.5061/dryad.3j9kd51nc