Abstract Detail

Systematics

Integrative taxonomy: investigating species boundaries in Malagasy Psorospermum using morphometrics and molecular phylogenetic methods.

I investigated species hypotheses for Psorospermum species in Madagascar by integrating morphological species hypotheses with clustering sequences in molecular phylogenetic data. The molecular phylogenetics of Psorospermum based on chloroplast and nuclear DNA shows well supported clades within Malagasy Psorospermum. Using multivariate analysis based on Gaussian mixture models (GMM) implemented in Mclust R packages, I investigated the morphospecies within nine well supported clades in Malagasy Psorospermum, and compared them with the molecular clusters; individuals for each taxon tip of the clades were measured for floral and vegetative characters. GMM identifies 30 morphogroups in Malagasy Psorospermum. Two clades out of the nine match the GMM morphogroups; four clades have more morphogroups than the GMM's while two clades have fewer morphogroups than GMM's. My results support the hypothesis that incongruence between different species delimitation methods is explained by the particular stage of the speciation process; in this study molecular analyses can detect divergence that has not been yet fully translated into morphological characters, and were not recovered by the GMM analyses.

Related Links:
Cycad Pages
World List Of Cycads

1 - California Academy of Sciences, Institute for Biodiversity Science and, Department of Botany, 55 Music Concourse Drive, Golden Gate Park, San Francisco, California, 94118-4599, United States

Keywords:
Psorospermum
species boundaries
Gaussian mixture models
Morphometrics
Madagascar.

Presentation Type: Oral Paper
Session: SYS3, Systematics III: Cooley Award presentations
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 10:30 AM
Number: SYS3003
Abstract ID:289
Candidate for Awards:George R. Cooley Award