Phylogenomics confirm the monophyly of Guzmania (Bromeliaceae: Tillandsioideae) and provide evidence for a hybrid origin of the widespread G. monostachia

Description

Premise: This study presents a phylogenomic framework to clarify the evolutionary origin of Guzmania within the broader Tillandsioideae. Guzmania represents ~15% of extant diversity in Tillandsioideae and includes the widespread G. monostachia, whose distribution spans northern South America, Central America, the Caribbean, and southern Florida—its northernmost limit. Populations of G. monostachia are in decline recently due to habitat loss and fragmentation, with Florida populations particularly vulnerable to anthropogenic threats. Understanding the evolutionary history of these lineages is essential for assessing genetic diversity and guiding conservation efforts. Methods: We assembled new chloroplast and nuclear genome references for G. monostachia to construct a novel plastome set and a nuclear SNP dataset. These were integrated with public sequence data to infer phylogenomic hypotheses and estimate divergence times across Tillandsioideae. We also performed per-site log likelihood analyses to visualize phylogenetic signal across two discordant topologies for G. monostachia. Key results: We recovered a monophyletic Guzmania, but many relationships within Tillandsioideae remain unresolved. Notably, phylogenetic analyses revealed conflicting signals about the monophyly of G. monostachia, with some trees placing G. fuerstenbergiana and G. remyi nested within. Conclusions: Our findings underscore the limitations of large-scale chloroplast data for clarifying Tillandsioideae phylogenies. Nonetheless, results suggest a possible hybrid origin for G. monostachia and a distinct evolutionary trajectory for Florida populations. Data and insights generated by our study provide a foundation for and enable future genetic diversity studies and conservation planning for this threatened lineage.

Institutions

• University of Florida

  FL, Gainesville
• Florida Museum of Natural History

  FL, Gainesville

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