Subfamily Eosymtinae Bousfield & Hendrycks, 1994

Eosymtinae Bousfield & Hendrycks 1994: 43 .— Hendrycks & Bousfield 2004: 49.— Labay 2018: 221.

Type genus. Eosymtes Bousfield & Hendrycks, 1994: 43 .— Hendrycks & Bousfield 2004: 49.

Type species. Eosymtes minutus Bousfield & Hendrycks, 1994

Genera. Eosymtes Bousfield & Hendrycks, 1994, Cognateosymtes Labay, 2018 .

Diagnosis (from Hendrycks & Bousfield 2004 with additions). Body smooth. Urosome 2 occluded or not dorsally. Rostrum short.

Upper lip, apical lobes slightly asymmetric. Lower lip regular, inner lobes weak, narrowly sloped. Molar of both left and right mandibles columnar, with strongly ridged grinding surface, with medial molar plumose seta; left lacinia multidentate, right lacinia blade-like; row of raker setae short, with 4–7 pectinate blades; palp large. Maxilla 1, outer plate with 9 apical strong pectinate setae (spine-like setae), inner plate with 2 stout setae. Maxilla 2, inner plate with 2 strong submarginal and subapical setae. Maxilliped, inner plate with 2–4 small apical spiniform setae; palp segment 3 not produced distally, dactyl slender, slightly curved, not pectinated.

Gnathopods 1 & 2 medium, similar in form, carpus shorter than propodus, palmar margin oblique, without submedial tooth.

Pereopods 5–7, basis broadened, rounded behind, hind margin weakly serrate, basis 5 broadened in distal half, basis 6 and 7 broadened in proximal half. Epimeral plates 1–3, hind corners slightly acuminate, not produced. Telson keeled proximally, apex rounded.

Distribution. Marine waters of boreal part of Pacific Ocean.

Remarks. Subfamily Eosymtinae is close to Pleusymtinae Bousfield & Hendrycks, 1994 but differs from the latter as follows: lower lip, outer lobes slightly apart, inner lobes weak, narrowly sloped. Mandible, left and right molars with medial molar plumose seta; right lacinia present, blade-like. Maxilla 1, inner plate with two apical setae. Maxilla 2, inner plate with two marginal plumose setae. Maxilliped, inner plate with 2–4 small apical spiniform setae. Epimeral plates 1–3, posterior corners slightly acuminate, not produced.