From proto- + gastric. <span class="searchmatch">protogastric</span> (not comparable) That covers the gastric area of brachyuran crabs...
pharyngogastric philogastric pneumogastric polygastric postgastric pregastric <span class="searchmatch">protogastric</span> renogastric stomatogastric supragastric tachygastric transgastric trigastric...
protoflexid protoflexus protofluoride protoform protogalactic protogalaxy <span class="searchmatch">protogastric</span> protogeneous protogenesis protogenetic protogenic protogeometric Proto-Germanic...