Giant eggshells reveal the secrets of Madagascar’s elephant birds | SciTechDaily

[Posted by Chuck Almdale, submitted by Lillian Johnson]

Three decades ago two kids in southern Madagascar wanted to sell me an Elephant Bird’s egg that looked a lot like the ones pictured in this article. I assumed was a fake. It looks like I was wrong. Oh well, U.S. Customs would never have let me bring it into the country in my luggage anyway.

Secrets of 9-Foot Tall, 1,500-Pound Elephant Birds Revealed by Ancient Eggshells
SciTechDaily | Univ. of Colorado Boulder | 9 Mar 2023

Elephant Birds weighted over half a ton and they’ve been extinct for a millennium. Their eggs were 1 1/2 feet long and can still be found, shattered into many pieces, in the sand dunes of Madagascar today. Analysis of the shells is revealing new information.

The cladogram at bottom indicates that Elephant Birds split off from the Kiwis 57.24 million years ago.
Link to larger version of cladogram.

Link to the Paper
Molecular exploration of fossil eggshell uncovers hidden lineage of giant extinct bird
Nature.com | Grealy, Miller, et.al. | 28 Feb 2023

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.