The Phylogenetic and Biogeographic History of Cranes (Gruidae)

Author

• Phillip Conrad Williams, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2026

Degree Name

Doctor of Philosophy

Department

Zoology

First Advisor

Ibrahim, Kamal

Abstract

Cranes (Gruidae) are a globally distributed clade of large, wetland-associated birds. Prior phylogenetic analyses have shown there to be two major subfamilies, Balearicinae and Gruinae, and five consistently recovered clades within Gruinae. However, the relationships among those five clades has remained contentious. In addition, little has been done to reconstruct the biogeographic history of cranes. To that end, I first inferred phylogeny using a large, nuclear dataset sampled from all 15 extant crane species and two outgroup species. The phylogeny mostly agreed with previous analysis using whole mitochondrial genomes but differed in that the Anthropoides species group formed a sister clade to a clade consisting of Grus canadensis and the Antigone species group. A time-calibrated phylogeny was obtained which suggested that Gruidae originated ~32.1 million years ago, Gruinae originated ~21 million years ago, and the radiation of the Gruinae cranes took place ~6.5 – 9 million years ago. Ancestral range reconstruction supported an Asian origin for Gruinae and that jumps to new continents played an important role in crane biogeographic history. To explore the current and future distributions of cranes, I developed ecological niche models (ENM) for each species. Breeding and wintering ENMs were constructed using Maxent and a novel year-round, neural-network-based method using TabNet. These models generally performed well when evaluated on temporally isolated occurrence data. The time-aware TabNet models provide new insight into shifting migration timing under climate change. Together, these analyses provide a stronger understanding of crane diversification and abiotic niches.