Caprellidira Leach, 1814

Ariyama, Hiroyuki & Mori, Keisuke, 2023, Two Distinctive Amphipods (Crustacea) Collected from the Ariake Sea, Western Japan, with the Description of a New Species, Species Diversity 28 (1), pp. 31-44 : 31-32

Parvorder Caprellidira Leach, 1814 Superfamily Photoidea Boeck, 1871 Family Ischyroceridae Stebbing, 1899 [Japanese name: Kamakiri-yokoebi-ka] Genus Scutischyrocerus Myers, 1995 [New Japanese name: Kuda-yokoebi-zoku]

Scutischyrocerus Myers, 1995: 88 .

Type species. Scutischyrocerus scutatus Myers, 1995 , by original designation.

Diagnosis [emended from Myers (1995)]. Body and coxae forming a cylinder. Head with produced lateral cephalic lobe, anteroventral margin deeply recessed; antennae much shorter than body length, setose posteriorly; antenna

1 peduncular article 1 short, articles 2, 3 elongate, accessory flagellum absent or vestigial; mandibular palp strong, article 2 longest, article 3 rod-shaped; maxilla 1 inner plate triangular, bare; coxa 1 small, produced anteroventrally, coxae 2–5 greatly enlarged, shield-like, coxa 5 with small posterior lobe, coxae 6, 7 small; gnathopods 1, 2, subchelate; pereopods 3, 4 short, bases expanded, carpi partially telescoped into meri, dactyli elongate; pereopods 5–7 progressively longer, bases expanded, dactyli short, curved; uropods 1–3 biramous, peduncles longer than both rami, uropod 3 outer ramus with 2–3 hooks distolaterally; telson short.

Included taxa. Scutischyrocerus japonicus sp. nov.; S. scutatus .

Remarks. As the following new information was revealed through the present study, diagnosis of the genus is emended herein: (1) accessory flagellum vestigial, (2) gnathopod 2 except for coxa not so larger than gnathopod 1 in both sexes, and (3) uropod 3 outer ramus with 3 hooks.