An annotated checklist of the species of Lopogastrida and Mysida (Crustacea Peracarida) from Thailand and its adjacent waters Author Yolanda, Rofiza Author Ambarwati, Reni Author Rahayu, Dwi Anggorowati Author Budijastuti, Widowati Author Fitrihidajati, Herlina Author Kuntjoro, Sunu Author Rachmadiarti, Fida Author Purnomo, Tarzan text Zootaxa 2023 2023-02-20 5244 3 201 232 http://dx.doi.org/10.11646/zootaxa.5244.3.1 journal article 10.11646/zootaxa.5244.3.1 1175-5326 C0EA98E9-2DE2-4B56-B0EB-0E08308923F2 Rhopalophthalmus hastatus Hanamura, Murano & Man, 2011 Type locality. Merbok mangrove estuary, Kedah , Malaysia ( Hanamura et al. 2011 ) . Record from Thailand . Surat Thani ( Hanamura et al. 2011 ) and Songkhla Lagoon System ( Lheknim & Yolanda 2020 ; Yolanda 2021; Yolanda et al. 2022b ). Habitat and depth range. Hanamura et al. (2011) did not mention the depth of this species when recorded in Thailand , but they indicated that this species was commonly captured in the middle to upper area of mangrove riverine waters. Later, Lheknim & Yolanda (2020) , Yolanda (2021) and Yolanda et al. (2022b) reported that this species was very abundant at the shallow zone of the Songkhla Lagoon System (~ 1 to 2 m ). Distribution. This species is only known from Malaysia ( Hanamura et al. 2011 ; Ramaran et al. 2012a) and Thailand ( Hanamura et al. 2011 ; Lheknim & Yolanda 2020 ; Yolanda 2021; Yolanda et al. 2022b ). Remarks. Among the species of the genus Rhopalophthalmus , this species can be easily distinguished by the antennal sympod bearing 1 prominent mesial second spine flanked by a much shorter more mesial spine, and 1–3 short lateral spines ( Hanamura et al. 2011 ).