en عمومى General پژوهشي Research <span style="font-size:11pt"><span style="line-height:120%"><span style="tab-stops:40.5pt"><span style="font-family:Calibri,sans-serif"><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span style="font-family:&quot;Times New Roman&quot;,serif">This study presents a comparative morphological analysis of the first zoeal stage of six commercially important portunid crab species: <i>Scylla tranquebarica</i>, <i>Portunus segnis</i>, <i>Charybdis orientalis</i>, <i>Charybdis annulata</i>, <i>Charybdis hellerii</i>, and <i>Thalamita prymna</i>, reared under laboratory conditions. Larvae were cultured and examined using standard microscopic techniques, and key morphological characters were recorded, illustrated, and compared across species. Diagnostic features of the first zoeal stage, including carapace spination, appendage segmentation, setation patterns, and overall body proportions, were evaluated to identify interspecific variation. The results revealed clear species-specific differences in zoeal morphology, particularly in the structure and arrangement of dorsal and lateral spines, antennal development, and maxilliped setation patterns. These morphological variations provide reliable taxonomic characters for species-level identification during early larval stages. The study contributes to a better understanding of early developmental diversity within Portunidae and supports larval identification in both ecological and aquaculture contexts.</span></span></span></span></span></span></span> Zoea I, Portunidae, Crustacean larvae, Morphology, Comparative study, Brachyura. 15 27 http://injbir.com/browse.php?a_code=A-10-40-2&slc_lang=en&sid=1 F.S. Ghory farhanaghory@yahoo.com 1003194753284600664 1003194753284600664 Yes Marine Reference Collection and Resource Centre, University of Karachi, Karachi-75270 Pakistan