Fig 1.
The map shows the sampling sites in Viet Nam and sequences of other regions were obtained from GenBank.
Region I (Sunda Shelf, sites = solid rounds) includes sampling sites in Viet Nam, Thailand, Malaysia and Myanmar. Region II (Wallacea, sites = solid squares) includes sampling sites in the Philippines and Indonesia. Region III (Sahul Shelf, sites = solid stars) includes sampling sites in Australia. Region IV (site = solid triangle) and V (sites = solid diamond) are sampling sites in the Bay of Bengal and the Coast of Japan, respectively. IDN = Indonesia, MAS = Malaysia, MYA = Myanmar, THA = Thailand, VIE = Viet Nam. LS = Ly Son Island, CD = Con Dao Island, PQ = Phu Quoc Island. Dotted line is the boundary line. Source of digital map: The National Oceanic and Atmospheric Administration (NOAA), USA, public domain data. Wallace’s and Lydekker’s Lines were adapted from Van Welzen et al. [30].
Fig 2.
Variation in morphology of Halophila major leaves collected from Vietnamese waters.
A: Ly Son Island; B: Phu Quoc Island; C = Con Dao Island. Scale in each figure = 1 mm.
Table 1.
Leaf dimensions of Halophila major collected in the Vietnamese waters.
Fig 3.
Phylogenetic tree of members of section Halophila inferred from Maximum likelihood and Bayesian inference.
Data set based on 600 bp of ITS1-5.8S-ITS2. Bootstrap values and posterior probability of each method are shown at each node: (left) maximum likelihood; (right) Bayesian inference. *, full support (bootstrap value = 100, posterior probability = 1). 1–8 are smaller groups of Halophila major. See S1 Table for more information. The consensus tree was constructed by Dendro Scope software, version 3.2.10.
Table 2.
Evolutionary divergence (un-shading cells) as measured by estimated total fragment and per nucleotide differences (shading cells) of Halophila major.
Table 3.
Summarized Halophila major sample size, number of haplotypes observed, and estimates of genetic diversity.
Fig 4.
Distribution of haplotype frequency of Halophila major at different regions.
Twenty two haplotypes are defined by different colours/background. The data were processed by PopART software.
Fig 5.
Haplotype network of 22 haplotypes and their distribution found for Halophila major worldwide.
Haplotypes are written beside or in the circles. Each short segment in the distance between two genotypes is a single mutation. Each dotted line rectangle presents each small group, numbers (1–8) following The data were processed by PopART software.
Table 4.
AMOVA (analysis of molecular variance) results for ITS variation of Halophila major collected at five regions.
Fig 6.
The relative divergence times based on ITS1-5.8S-ITS2 for Halophila spp.
The 95% Highest Density Probability (HPD) intervals are provided at each node; upper value = node divergence time (Mya), lower value = posterior probability values (p.p.). Time-calibrated phylogeny was processed by Beast v2.5.