Supplementary data 1: Locations, coordinates and seagrass species at sampling sites. Cr = Cymodocea rotundata, Cs = Cymodocea serrulata, Ea = Enhalus acoroides, Hb = Halophila beccarii, Ho = Halophila ovalis, Hu = Halodule uninervis, Th = Thalassia hemprichii, *: dominant species.

Coordinates
No / Locations / Abb. / Long. / Lat. / Seagrass species
1 / Tuan Le / TL / 109021’ / 12045’ / Ea*, Th, Ho
2 / My Giang / MG / 109017’ / 12029’ / Cs, Cr, Ea*, Th, Ho
3 / Song Lo / SL / 109012’ / 12009’ / Ea*, Th, Hu, Cr
4 / Thuy Trieu / TT / 109011’ / 1202’ / Ea*, Th, Hu, Ho, Hb
5 / Cam Phuc Nam / CPN / 109011’ / 11056’ / Ea*, Th
6 / Cam Thinh / CT / 109009’ / 11053’ / Ea*, Th

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Supplementary data 2: List of taxa and Genbank accessions used for the phylogenetic analysis.

N0 / Taxa / GB Accession / Sources
1 / Allium sativum / Other monocotyledonous plants / AAO13809 / Direct submission
2 / Anthurium amnicola / JAT45520 / Direct submission
3 / Elaeis guineensis / XP 010935936 / Direct submission
4 / Iris spp. ser. hexagonae / ALT55649 / Tian et al. (2015)
5 / Musa acuminata subsp. malaccensis / XP 009382679 / Direct submission
6 / Nelumbo nucifera / NP 001289777 / Direct submission
7 / Phoenix dactylifera / XP 008810429 / Direct submission
8 / Zostera marina / Seagrass / KMZ73511 / Olsen et al. (2016)
9 / Ectocarpus siliculosus / Algae / CBJ32985 / Cock et al. (2010)
10 / Entomoneis paludosa / CBP94206 / Nguyen-Deroche et al. (2012)
11 / Microcoleus vaginatus / EGK88687 / Starkenburg et al. (2011)
12 / Nitzschia palea / CBP94204 / Nguyen-Deroche et al. (2012)
13 / Thalassiosira pseudonana / EED91948 / Armbrust et al. (2004)

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