Circumscription and phylogenetic relationship of Prostanthera densa and P. marifolia (Lamiaceae)

Abstract

Prostanthera densa A.A.Ham. and P. marifolia R.Br. (Lamiaceae) are endemic species with restricted distributions within the near-coastal regions of New South Wales (Australia). Prostanthera marifolia was previously presumed extinct, but is now known from three small geographically close populations in the Manly-Warringah area of metropolitan Sydney. This species is morphologically very similar to P. densa, which is known from five disjunct populations, distributed south from Port Stephens to Jervis Bay. The nucleotide sequence variation of the psbA-trnH chloroplast spacer region, and the external transcribed spacer (ETS) region of nuclear ribosomal DNA were analysed to evaluate the phylogenetic relationships and taxonomic integrity of these species. Trees generated from psbA-trnH and ETS data provided support for recognising P. marifolia as separate from P. densa. A multivariate statistical evaluation of the morphological variation of each population of these taxa supported the distinction of these two morphologically similar and closely related species. Based on molecular and morphological data we recommend these two species continue to be recognised. The ETS data highlighted the genetic distinctiveness of four disjunct populations of P. densa. Since there is apparently no gene flow between populations of P. densa, it was concluded that the conservation of this species requires all populations to be protected.

Draft genome of a high value tropical timber tree, Teak (Tectona grandis L. f): insights into SSR diversity, phylogeny and conservation

“…The plastid gene psb B which codes for the core protein of Photosystem II, has the highest level of translation among the chloroplast genes and provides an excellent opportunity to investigate an unusual evolutionary situation. 65 Phylogenetic utility of psb B gene sequences has been tested in many plant families under the Order Lamiales such as Lamium , 66 Chelonopsis , 67 Salvia 68 and Prosanthera 69 among others. Similar to psb B, studies on molecular systematics have undoubtedly proved that ycf gene is more variable than mat K in many taxa to resolve the phylogeny issues.…”

Molecular and morphological analyses support recognition ofProstanthera volucris(Lamiaceae), a new species from the Central Tablelands of New South Wales

“…Schlick-Steiner et al (2009) provide a framework for an integrative taxonomic approach, suggesting that morphology be used as a primary line of evidence, followed by a genetic discipline. Previous studies of Prostanthera have incorporated phenetic analyses of morphological characters to rigorously assess phenotypic variation between putative taxa (Conn 1984;Conn et al 2013;Wilson et al 2017;Conn et al 2021), and the use of these techniques is widely accepted.…”

“…Previous molecular studies of Prostanthera incorporating Sanger sequencing data have provided some species-level resolution (Wilson et al 2012;Conn et al 2013;Conn et al 2016;Conn et al 2021;O'Donnell et al 2021). Phylogenetic analysis by O'Donnell et al (2021), however, recovered discordant topologies between nuclear and chloroplast datasets, suggesting that hybridisation, introgression, or incomplete lineage sorting may have occurred within Prostanthera.…”

“…Characters were selected from previous morphological studies of Prostanthera (Conn 1984;Williams et al 2006;Conn et al 2013), with additional characters added following preliminary examination of specimens (i.e. indumentum direction and density).…”

“…The unweighted pair-group method using arithmetic means (UPGMA) was used as a means for cluster analysis as it is considered to accurately represent real distances between individuals in taxonomic datasets (Chappill & Ladiges 1992;Copeland et al 2007). Semi-strong hybrid multidimensional scaling (SSH-MDS) was used for ordination analyses as it has been shown to accurately reflect phenetic patterns (Minchin 1987) and has frequently been used in recent morphological phenetic studies, including studies of Prostanthera (Plunkett et al 2009;Conn et al 2013;Bean 2014;de Salas & Schmidt-Lebuhn 2018).…”