Yellow-eyed Penguin. Photo courtesy of Shutterstock
Closest Living Relative
According to systemics scientists suspect that the closest living relative to Erect-Crested Penguins is the Yellow-Eyed Penguin. By analyzing mitochondrial and nuclear DNA evidence, they think that the two species split around 8 million years ago during the Late Miocene.
Here are some key differences:
Yellow-Eyed Penguins are 10-30% heavier ( 11-13lbs) than Erect-Crested Penguins (10lbs).
Erect-Crested penguins are about two inches taller (26 inches vs. 24 inches).
Erect-Crested penguins have an estimated population size of 150,000 versus Yellow-Eyed penguins who have a population between 2,600-3,000. Both are endangered.
Closest Relative
By studying the phylogenetic tree of crested penguins, the closest relative to Erect-Crested Penguins is identified as the now-extinct penguin genus Madrynornis. Fossilized Madrynornis were dated to about 10 million years ago in the late Miocene. Scientists suspect that Madrynornis separated from crested penguins about 12 million years ago. The phylogeny also suggested Madrynornis also had yellow head ornamentation.
Citations
Baker, A. J., Pereira, S. L., Haddrath, O. P., & Edge, K. A. (2006). Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling. Proceedings. Biological sciences, 273(1582), 11–17. https://doi.org/10.1098/rspb.2005.3260
Cole, T. L., Rawlence, N. J., Dussex, N., Ellenberg, U., Houston, D. M., Mattern, T., Miskelly, C. M., Morrison, K. W., Scofield, R. P., Tennyson, A. J. D., Thompson, D. R., Wood, J. R., & Waters, J. M. (2018, October 25). Ancient DNA of crested penguins: Testing for temporal genetic shifts in the world's most diverse penguin clade. Molecular Phylogenetics and Evolution. https://www.sciencedirect.com/science/article/abs/pii/S1055790318306274.
Hospitaleche, C. A., Tambussi, C., Donato, M., & Cozzuol, M. (2007). A new Miocene penguin from Patagonia and itsphylogenetic relationships - Acta Palaeontologica Polonica. http://www.app.pan.pl/article/item/app52-299.html.
Ocean Helper. (2021, April 23). The Erect-Crested Penguin & Yellow-Eyed Penguin. Ocean Helper. https://oceanhelper.com/blogs/news/the-erect-crested-penguin-yellow-eyed-penguin?fbclid=IwAR3MN0-8_0Yw5QmcezlXakR1QoaKS0K3EjCeLQ8uCumFVH_XmIMDO7AZiyg.
Martínez, I., D. A. Christie, and F. Jutglar (2020). Erect-crested Penguin (Eudyptes sclateri), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.bicpen1.01