Morphological and molecular evidence for major re-circumscriptions in and eight new species of Melichrus R.Br. (Ericaceae subfam. Epacridoideae) in eastern Australia

Helen T. Kennedy; Ian R. H. Telford; Darren Crayn; Jeremy J. Bruhl; Rose L. Andrew

doi:10.1071/SB24031

RESEARCH ARTICLE (Open Access)

Contents Vol 38(3)

Morphological and molecular evidence for major re-circumscriptions in and eight new species of Melichrus R.Br. (Ericaceae subfam. Epacridoideae) in eastern Australia

Helen T. Kennedy

^A ^B ^* , Ian R. H. Telford

^A , Darren Crayn

^C ^D , Jeremy J. Bruhl

^A and Rose L. Andrew

^A

+ Author Affiliations

- Author Affiliations

^A Botany and N.C.W. Beadle Herbarium, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.

^B Australian National Herbarium, Centre for Australian National Biodiversity Research (a joint venture between Parks Australia and CSIRO), GPO Box 1700, Canberra, ACT 2601, Australia.

^C Australian Tropical Herbarium, James Cook University, Cairns, Qld 4870, Australia.

^D Centre for Tropical Environmental Sustainability Science, James Cook University, Cairns, Qld 4870, Australia.

^* Correspondence to: helen.kennedy@csiro.au

Handling Editor: Russell Barrett

Australian Systematic Botany 38, SB24031 https://doi.org/10.1071/SB24031

Submitted: 2 September 2024 Accepted: 2 March 2025 Published: 16 April 2025

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

The genus Melichrus R.Br. has received very little taxonomic attention and treatments have largely disagreed on species delimitation. The eastern Australian clade of Melichrus was last revised in 1958. Over 60 years later we present new, in-depth evidence for species delimitation. A morphological dataset (90 individuals from 68 populations, scored for 26 characters) was analysed using NMDS ordination with Bayesian Inference cluster modelling (mclust) and UPGMA hierarchical clustering to detect morphological discontinuities in the genus that may indicate species boundaries. Discontinuities in the morphological analyses were compared with those apparent in clustering (principal component analysis, SplitsTree Neighbour-Net, STRUCTURE and conStruct) and statistical analyses (H_E, H_O, F_IS and F_ST) of a DArTseq SNP dataset of 548 samples from 110 populations of Melichrus. These new lines of evidence form the basis of detailed recommendations for a revised species taxonomy of Melichrus including the description of eight new species, recircumscription of previously described species and the correction of a longstanding nomenclatural misapplication.

Keywords: DArTseq, Epacridoideae, Ericaceae, Melichrus, morphometrics, phenetics, reduced representation, species delimitation, taxonomy.

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