Serène, 1971
Carapace without 2-3 longitudinal line bearing 5-7 granules plus larger ones; this species is very similar to Jonas formosus, however, different, 1. Interior supraorbital spine exceeding the exterior spine of equally bifurcate rostrum: 2. Interior infraorbital spine much shorter than supraorbital spine, both of which are equal in size: 3. External orbital spine is much smaller than 1st antero-lateral spine (in J. choprai, 1st antero-lateral spine extremely large in size): 4. Anterior third of carapace smooth: 5. Carapace very large. 6; 1.33 times as long as broad; in Jonas formosus it is 1.50 times in males and 1.60 times in female. (K. Sakai, after Serène, 1971b: 904)
Type locality: China Sea.
Range: Taiwan; China Sea (Serène, 1971).