First Zoeal Stages of Six Species of Hemigrapsus (Decapoda: Brachyura: Grapsidae) from the Northern Pacific Including an Identification Key

Abstract

Abstract We obtained the first zoea stages of six grapsid crabs from laboratory-hatched material: Hemigrapsus penicillatus, H. sanguineus, H. longitarsis, H. sinensis, H. nudus, and H. oregonensis. They are re-described and illustrated in detail. Zoeal characteristics are compared among these species. The main difference between four eastern Asian species (H. penicillatus, H. sanguineus, H. longitarsis, and H. sinensis) and two American species (H. nudus and H. oregonensis) is the character of the antennal exopod tip, which is unarmed in the former and spinulate in the latter. In order to facilitate the study of plankton-collected material, we provide a key for the identification of the zoeae of Hemigrapsus from the northern Pacific.