Md-Zain BM, Abdul-Mutalib SA, Aifat NR, Masstor NH, Mohd-Yusof NS, Mohd-Hashim A, Abdul-Latiff MAB, Yaakop S,Samat A. 2018. Molecular phylogenetic inference of White-Spotted Guitarfish (Rhynchobatus australiae) collected from local Malaysianfish markets. Biodiversitas 19: 1382-1386. The white-spotted guitarfish (Rhynchobatus australiae) is in high demand at local Malaysianfish markets because its fins are a valuable food source. To date, few molecular studies have characterized their genetic identity. Wehave conducted a molecular study to infer the phylogenetic relationships of white-spotted guitarfish, which portray a similarmorphology to sharks and rays. The main objective of this study was to determine the phylogenetic position of R. australiae usingcytochrome oxidase I (COI) sequences of mitochondrial DNA based on fish samples collected from local Malaysian fish markets. Thisstudy included nine genetic samples of R. australiae and fourteen samples from other members of the shark and ray families, includingSphyrna lewini (Sphyrnidae), Rhizoprionodon oligolinx and Carcharhinus sorrah (Carcharhinidae), Dasyatis zugei, Himantura walga,Himantura gerradi, Himantura jenkinsii and Neotrygon kuhlii (Dasyatidae). Chimaera fulva, a member of the Chimaera family, wasused as the outgroup. Sequences in size of ~701 base pairs were successfully obtained from all fish samples. The phylogenetic treetopology was reconstructed using distance-based (neighbor-joining) and character-based (maximum parsimony) methods using MEGAand PAUP software. Results indicated that R. australiae formed monophyletic clade and is closely related to sharks (Sphyrnidae andCarcharhinidae). This conclusion was also supported by genetic distance analysis which indicated that Rhynchobatidae and sharks(Carcharhinidae and Sphyrnidae) were closer to each other than to rays (Dasyatidae). This study has proven the efficiency of the COImitochondrial locus in revealing the phylogenetic position of R. australiae. Research findings from this study have increased ourunderstanding of the phylogenetic relationships among guitarfish, sharks, and rays, and their respective taxonomic positions are giventheir shared morphological characters. This will benefit us in identifying these fish species before consumption from local fish markets.