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 Gastrosaccus dunckeri Zimmer, 1915 Type locality. Ceylon ( Zimmer 1915 ) . Record from Thailand . South-eastern Andaman Sea, next to Phuket Island ( Fukuoka & Murano 2002 ). Habitat and depth range. Marine, depth: 28–32 m ( Fukuoka & Murano 2002 ) . Distribution. This species is distributed from Sri Lanka to New Guinea ( Zimmer 1915 ), India (W.M. Tattersall 1922 ; Pillai 1957 ; Shyamasundari 1973 ; Biju & Panampunnayil 2009 ; Biju et al. 2014 ; 2016 ), Mozambique (O.S. Tattersall 1958 ), Singapore (O.S. Tattersall 1960 ), Arabian Sea ( Pillai 1964 ), South China Sea ( Ii 1964 ), East China Sea ( Wang & Liu 1997 ), and Andaman Sea ( Fukuoka & Murano 2002 ). Remarks. Species of the genus Gastrosaccus are divided into two main groups, Normani -group and Spinifergroup . In the first group; endopods of third pleopods of male are completely lacking, there are many spines on the inner margin of the uropodal endopod, and 10 to 12 lateral spines on the telson with wide space between the penultimate and apical ones., Whereas in the Spinifer -group; both rami of the second male pleopods are well developed and straight, there are six spines on the inner margin of the uropodal endopod and six lateral spines on the telson (O.S. Tattersall 1952 ). The species G. dunckeri belongs to the Normani -group and resembles G . sanctus ( Spinifer -group). However, in G . dunckeri , the posterior margin of the carapace is armed with two extremely long, reflexed lappets which are truncated distally, while in. G . sanctus , the posterior margin of carapace is produced into a pair of oval lappets (one on each side of the median line) which are reflexed forwards.