Abstract Detail

Systematics

Ranarivelo, Heritiana [1].

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

Psorospermum species in Madagascar have long been in need of a taxonomic revision. The last treatment was by Perrier de La Bâthie in 1955. Using integrating morphological species hypotheses with clustering sequences in molecular phylogenetic data, I investigated species hypotheses for the Malagasy Psorospermum species. 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 morphospecies in Malagasy Psorospermum. Two clades out of the 9 match the GMM morphospecies; four clades have more morphogroups than the GMM morphospecies while 2 clades have fewer morphogroups than GMM morphospecies. I recognize 29 species. 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.

1 - California Academy of Sciences, Botany Department, 55 Music Concourse Drive, San Francisco, CA, 94118, USA

Keywords:
Psorospermum
species delimitation
morphometrics
Gaussian mixture models
Madagascar.

Presentation Type: Oral Paper
Session: SYS1, Systematics I: Land plants, Gymnosperms to Rosids part 1
Location: Tucson H/Starr Pass
Date: Monday, July 29th, 2019
Time: 4:45 PM
Number: SYS1013
Abstract ID:772
Candidate for Awards:None