Morphology of the Decapodid Stages of Argis lar (Owen 1839) (Caridea, Crangonidae) from Kronotsky Gulf, Eastern Kamchatka, Russia

Abstract Two decapodid stages of the shrimp Argis lar (family Crangonidae) from the plankton off Kronotsky Gulf, northwestern Pacific, eastern Kamchatka, are described. The available larvae were morphologically compared with decapodids of other species of this family with a shortened development. The first and second decapodid stages are similar in size and structural features of the pleon, carapace, antennae, mandibles, maxillae, pereiopods, and pleopods. The morphology of the telson, maxillipeds, and antennules in the first and second decapodid stages of A. lar differ significantly. At the second decapodid stage, the posterior median spine shifted towards the middle of the carapace. The number of antennular and maxilliped endopod segments increased. The epipod appeared in the third maxilliped. The shape of the telson changed. The terminal spines in the telson disappeared, and the relative length of the angular setae decreased. Kuro shrimp are suggested to have three to five larval stages.