A species-level phylogeny of eastern Australian Phebalium Vent. sect. Phebalium Duretto & Heslewood (Rutaceae; Zanthoxyloideae).

Sangay Dema (Botany & N.C.W. Beadle Herbarium, University of New England); Rose L. Andrew (Botany & N.C.W. Beadle Herbarium, University of New England); Ian R.H. Telford (Botany & N.C.W. Beadle Herbarium, University of New England); Jeremy J. Bruhl (Botany & N.C.W. Beadle Herbarium, University of New England).

Phebalium Vent. sect. Phebalium Duretto & Heslewood is an Australian endemic monophyletic group of species. It has two geographic clades (Mole et al. 2004; Duretto et al. 2023), with 14 species distributed in south-western Australia and 21 in eastern Australia. We have hypothesised more than 35 taxonomic changes. SD’s PhD project focussed on testing the species limits of the P. squamulosum complex has supported the recognition of at least 14 new species and raising seven subspecies to the rank of species. Duretto et al. (2023) subsumed Microcybe into Phebalium as two new sections in the genus. Most species-level relationships in Phebalium were unresolved, and the study did not include putative new taxa of the eastern Australian clade recognised at the N.C.W. Beadle Herbarium. Our SNP-based phylogenetic analysis of all eastern Australian Phebalium taxa, including newly delimited species, was carried out using maximum likelihood and maximum parsimony criteria in program IQ-TREE2 (Minh et al. 2020; Minh et al. 2022) and PAUP v.4.0a168 (Swofford 2003) respectively. We also inferred phylogenetic relationships under a coalescent model using SVDquartet (Chifman and Kubatko 2014) implemented in package PAUP*v.4.0a168. The phylogenetic relationships inferred under all models were concordant. Our results supported three major clades within eastern Australian Phebalium corresponding to three species complexes: namely, P. squamulosum, P. glandulosum and P. nottii. The monophyly and inter-specific relationships of most eastern Australian Phebalium were resolved and will be discussed.