Morphological and molecular evidence reveals three new species of Lithocarpus (Fagaceae) from Bidoup-Nui Ba National Park, Vietnam

Abstract

Three new species, Lithocarpus bidoupensis Ngoc & Tagane, L. congtroiensis Ngoc & Yahara, and L. hongiaoensis Ngoc & Binh are described from Bidoup-Nui Ba National Park, Central Highland of Vietnam. Morphological analyses and Maximum likelihood tree based on genome-wide SNPs support the distinction of those species from the previously known taxa in the region. The three new species are considered to be endemic to the Bidoup-Nui Ba National Park and the preliminary conservation status for each species is evaluated as Critically Endangered.

Lithocarpus encleisocarpus (Korth.) A. Camus - A newly recorded from Vietnam and its phylogenetic relationship based on genome-wide SNPs

“…The materials including two samples of L. coalitus Hickel & A. Camus, the species that have unique morphological features in the genus, were used as an outgroup in phylogenetic analysis. This study material includes a part of Ngoc et al (2021) material. The detailed information on samples used for molecular analysis was shown in Table 1.…”

“…The total genomic DNA of L. encleisocarpus and its related species was used as templates to perform the next-generation sequencing (NGS). MIG-seq library was constructed using the given protocols with the modifications that had been previously published (Suyama and Matsuki, 2015;Ngoc et al, 2021).…”

“…For the phylogenetic analysis, the MIG-seq raw data was pretreated by using Trimmomatic 0.39 (Bolger et al, 2014) and then the Stacks 2.41 pipeline (Catchen et al, 2013;Rochette et al, 2019) was used for de novo SNP discovery with the parameters set as described by Takata et al (2019) and Ngoc et al (2021). The GTR+G model was used as recommended by jMrModeltest 2.1.10 ( Darriba et al, 2012) to construct a maximum likelihood tree of genome-wide SNPs data set using RAxML ver.…”

“…for Indo-China; Camus, 1948) including Vietnam (125 spp. ;Ho, 2003;Ban, 2005;Ngoc et al, 2016Ngoc et al, , 2018Ngoc et al, , 2021, Thailand (60 spp. ; Barnett, 1940;Phengklai, 2008;Strijk et al, 2014aStrijk et al, , 2014bStrijk et al, , 2019 and one North American species (Lithocarpus densiflorus Hook.…”

“…), has recently been treated as a member of a new monotypic genus Notholithocarpus (Manos et al 2008) In Vietnam, Lithocarpus is the most species-rich genus of the family Fagaceae. Approximately 125 species have been recorded, among which 48 are endemic to the country (Ho, 2003;Ban, 2005;Ngoc et al, 2016Ngoc et al, , 2018Ngoc et al, , 2021. However, we often encounter species of Lithocarpus that are difficult to identify at the species level, indicating we need more efforts to clarify its diversity and taxonomy accurately.…”