Jesogammarus (Jesogammarus) acalceolus sp. nov., male (7.4 mm), NSMT-Cr 29003 A maxilla 2, medial view B maxilliped, dorsal view C gnathopod 1, medial view D palmar margin of propodus and dactylus of gnathopod 1, medial view, some setae omitted E gnathopod 2, medial view F palmar margin of propodus and dactylus of gnathopod 2, medial view, some setae omitted G–I coxa-ischium of pereopods 5–7, respectively, lateral views J–O coxal gills on gnathopod 2–pereopod 7, respectively, lateral views P pleopod 1, lateral view, distal parts of rami omitted Q retinacula on peduncle of pleopod 1, lateral view R–S uropods 1–2, respectively, dorsal views T uropod 3, ventral view U distal part of proximal article and terminal article of outer ramus of uropod 3, ventral view V telson, dorsal view.