Laophontidae. Body slender, sub-cylindrical; urosome narrower than prosome and cephalothorax with integument coverted in pitted marks. Rostrum triangular and completely fused to cephalothorax. Genital field with pair of P6 widely separated and each leg represented by 2 setae. Sexual dimorphism in antennules, P3, P5, P6 and genital segmentation. Anal operculum convex, anal opening bordered by setular rows. Caudal rami with right and left rami including terminal seta tightly attached to each other. Antennule 7-segmented in female, 8-segmented in male; second segment with horn-shaped integumental protuberance. Antennary exopod with 4 setae. P1 exopod small, 2-segmented, not exceeding middle of Enp-1. P2-P4 all endopods 2-segmented and exopod 3-segmented, except male P3 endopod 3-segmented; enp-1 without inner and outer setae. Male P3 Enp-2 with 1 strong inner apophysis. Female P5 with 5 setae on endopod and 4 on exopod; endopodal lobe exceeding distal margin of small exopod; male endopodal and exopodal lobes vestigial, the former with 2 and the latter 3 setae. Type species monotypic.

The generic name is derived from the Latin 'strictus', meaning 'close' or 'tight', referring to the tightly attached caudal rami (including main setae on both rami).

Female: Body slender. Body length 1226 μm (range 1158 - 1292 μm, measured from anterior margin of rostrum to posterior margin of caudal rami). Largest width measured at posterior margin of cephalic shield: 185 μm. Entire body surface bumpy. Urosome narrower than prosome (Fig. 2A and B).

Cephalothorax with posterior margin fringed with small spinules and pattern of sensillae; integument coverted in pitted marks of various shapes and sizes. Rostrum triangular (Fig. 2A), completely fused to cephalothorax and with pair of sensilla near apex. All somites covered with tiny invisible, cuticle-patterned integument. There are postero-lateral protrusions on the dorsal surface of P2-P5 bearing-somites. Pleural areas well-developed and rounded, with lobate posterolateral angles. Several sensilla are present in all somites, except for the penultimate somite as in Fig. 2A, B. Pedigerous somites without hyaline frills, posterior margins fringed with small setules.

Urosome (Fig. 2A, B and Fig. 3A) gradually tapering posteriorly, five-segmented, comprising P5-bearing somite, genital double-somite, two free abdominal somites, and anal somite. Urosome without hyaline frills, with posterior margin fringed with setules except for anal somites.

Genital double-somite (Fig. 2A, B and Fig. 3A) with transverse surface ridge dorsally and laterally, indicating original segmentation and completely fused ventrally. Genital field (Fig. 3A) located near anterior margin with small-sized copulatory pore located in median depression. Pair of P6 widely separated, in genital field, each leg represented by small protuberence bearing 2 bare setae; outer seta slightly longer than inner seta.

Anal somite (Fig. 3B) with pair of dorsal tube-pores. Operculum semi-weakly convex, with serrate postrior margin and pair of sensilla on both sides. Anal opening triradiate, bordered by well-developed and serrate frill bearing setular rows.

Caudal rami (Fig. 3A and B) cylindrical, 1.5 times longer than wide; right and left rami including seta V tightly attached to each other; each ramus with 7 naked setae: seta I bare and shortest, seta II shorter than seta III, seta IV much shorter than seta V; seta V longest and very thick, shorter than urosome, 235 μm long; seta VI bare and small, dorsal seta VII tri-articulate at base, slightly shorter than seta III; additional spinular ornamentation present around distal margins.

Antennule (Fig. 3C) 7-segmented; fifth segment shortest, second segment longest. Segment 1 with spinular row at inner margin; with a long spinule at distal anterior margin. Second segment with horn-shaped integumental protuberance on outer middle margin; with row of small spinules on inner and outer margins. Segment 3 with row of small spinules on inner margin. Armature formula: 1-[1], 2-[8], 3-[7], 4-[1 + (1 + ae)], 5-[1], 6-[2], 7-[6 + acrothek]. Apical acrothek consisting of small aesthetasc fused basally to 2 bare setae.

Antenna (Fig. 3D) 3-segmented, comprising coxa, allobasis and free 1-segmented endopod. Coxa small, with two rows of spinules. Allobasis elongated; row of spinules on the side; without distinct surface sutures marking original segmentation, with 1 abexopodal seta near middle. Exopod small, with 2 pinnate setae apically, 1 naked seta and 1 plumose seta laterally. Endopod about as long as allobasis. Lateral armature consisting of 2 strong spines; apical armature consisting of 2 strong spines, and 3 geniculate setae (1 geniculate seta fused basally to additional short seta). Endopod with row of long spinules laterally and with frills along the outer edge surface.

Mandible (Fig. 4A) with well-developed gnathobase, bearing several multicuspidate teeth around distal margin and 1 long pinnate seta at distal corner. Coxa with row of spinules proximally. Mandibular palp 2-segmented, proximal segment (basis) with 1 plumose seta and 1 naked seta, distal segment (endopod) with 2 naked setae.

Maxillule (Fig. 4B). Praecoxa with little spinules around outer margin; arthrite strongly developed, with 1 naked seta on dorsal surface and 6 spines/setae around distal margin; with row of various-sized spinules on anterior surface and row of long spinules on anterior surface. Coxa with cylindrical endite bearing 1 naked seta and 1 pinnate spine. Basis with cylindrical endite bearing 2 naked setae, and 1 strong, curved, pinnate spine; on distall margin, endopod nearly incorporated into basis, forming small peduncle with 1 naked seta and 1 pinnate seta. Exopod 1-segmented, with 1 long pinnate seta.

Maxilla (Fig. 4C). Syncoxa with 3 endites; with two rows of spinules on anterior surface and row of setules on outer margin as figured. Proximal endite small and with 1 strong, pinnate spine. Middle endite with 2 pinnate setae, of which proximal one well-developed and fused basally to endite. Distal endite drawn out into claw-like protrusion bearing 1 distally unipinnate seta. Allobasis produced into strong pinnate claw, with 1 naked seta posteriorly and 1 slender pinnate anterior seta. Endopod were incorporated into allobasis, with 2 naked setae and 1 pinnate seta.

Maxilliped (Fig. 4D) comprising syncoxa, basis and 1-segmented endopod. Syncoxa with 2 plumose setae and several patches of spinules on syncoxa. Basis with 2 rows of spinules along palmar margin and row of spinules on outer lateral margin. Endopodal segment produced into strong pinnate claw.

Thoracic legs 1–4 (Fig. 5A, B and Fig. 6A, B) with wide naked intercoxal sclerite, triangle praecoxa, biramous, endopods 2-segmented, exopods 3-segmented, except for two-segmented endopod of P1. Coxae of P1-P4 larger than bases.

P1 (Fig. 5A). Coxa slightly longer than wide, with inner and outer spinular rows; with 1 spinular row on anterior surface. Basis with 1 plumose seta on outer margin and 1 strong pinnate seta near insertion of endopod; with spinular row along terminal margin and anterior surface and long spinules along inner margin. Exopod small, 2-segmented, not exceeding middle of Enp-1. Exp-1 with 1 pinnate outer spine. Exp-2 with 3 naked pinnate outer spines and 2 geniculate distal setae. Exopod with several spinules along outer margin. Endopod elongate and prehensile. Enp-1 2 times as long as exopod, with row of long spinules along inner margin. Enp-2 small, with 1 strong, denticulate claw apically and 1 small, naked seta subapically; with row of outer spinules and few anterior spinules.

P2–P4 (Fig. 5B and Fig. 6A, B). Praecoxa with row of distal spinules. Coxae with spinular rows along outer margin. Bases have a few spinules on anterior surface. Outer margin of basis with plumose seta (P2) or naked seta (P3-P4); each seta arising from short setophore. P2-P4 all endopod 2-segmented and exopod 3-segmented. All segments of exopod with elaborate pattern of spinules as illustrated; inner and outer margins of enp-1, outer margins of enp-2, inner margins of exp-1 with dense long slender spinules. P2-P4 enp-1 without inner and outer setae. P2 enp-2 1.4 times longer than enp-1; enp-2 with 2 plumose inner setae (1 long and 1 short) and 2 long plumose distal setae. P3 enp-2 2.3 times longer than enp-1; enp-2 with 3 plumose inner setae (2 long and 1 short), 1 plumose outer seta and 2 long plumose distal setae. P4 enp-2 2.5 times longer than enp-1; enp-2 with 2 plumose inner setae (1 long and 1 short), 1 plumose outer seta, and 2 long plumose distal setae. P2-P4 exp-2 shortest; exp-1 with 1 bipinnate outer spine; exp-2 with 1 plumose inner seta and 1 bipinnate outer spine. P2 exp-3 with 1 plumose inner seta, 3 bipinnate outer spine, and 2 long distal setae (1 plumose inner seta and 1 outer seta with both pinnate and plumose). P3-P4 exp-3 with 2 plumose inner seta, 3 bipinnate outer spine, and 2 long distal setae (1 plumose inner seta and 1 outer seta with both pinnate and plumose). Spine and setal formulae of P2-P4 as Table 1.

P5 (Fig. 5C) with separate exopod and baseoendopod, each with spinules as figured. Baseoendopod broad, forming outer setophore bearing basal naked seta; with 3 tube pores on anterior surface. Endopodal lobe exceeding distal margin of exopod; with 3 inner lateral pinnate setae and 1 pinnate seta and 1 naked seta on distal margin. Exopod small, slightly longer than wide, with 4 naked setae.

Male: Smaller and more slender than female. Total body length 965 μm (ranging from 894 - 1026 μm) measured from anterior margin of rostrum to posterior margin of caudal rami. Largest width measured at posterior margin of cephalic shield: 132 μm. Urosome distinctly narrower than prosome (Fig. 7A). All somites with densely spaced spinules on posterior margins. Sexual dimorphism in antennule, P3, P5, P6 and genital segmentation.

Urosome (Fig. 7A) comprised of P5-bearing somite, genital somite and 4 free abdominal somites.

Antennule 8-segmented (Fig. 7B), subchirocer, with geniculation between segments 5 and 6. Segment 1 with 1 row of long spinules along inner margin and with 1 naked seta on inner distal corner. Segment 2 with horn-shaped integumental protuberance on outer middle margin. Segment 4 represented by small sclerite. Segment 5 swollen. Segment 7 smallest. Segment 8 with shape of curved triangle. Armature formula: 1-[1], 2-[9], 3-[7], 4-[2], 5-[10 + 2 modified + (1 + ae)], 6-[4 modified], 7-[1], 8-[7 + 1 modified + acrothek]. Apical acrothek consisting of aesthetasc and 2 naked setae.

P2–P4. As in female, except for P3 with sexual dimorphism.

P3 (Fig. 8A). Endopod 3-segmented. Enp-2 with 1 strong inner apophysis, extending beyond enp-3; without spines and setae. Enp-3 with 2 plumose apical and 2 plumose inner setae. Exopod as in female.

P5 (Fig. 8B). Both legs fused medially. Baseoendopods fused to exopod, with setophore bearing outer naked basal seta. Endopodal and exopodal lobes vestigial, the former with one inner pinnate long seta and one outer naked shorter element, the latter with three elements of which the median longer and pinnate, the inner and outer shorter and naked.

P6 (Fig. 8B) asymmetrical, only one leg functional, the other fused to somite; each leg with two setae, of which inner element pinnate, outer element naked. Outer distal corner produced into short process bearing.

The species name refers to the region where the new species was discovered, Hupo Port on the east coast of Korea.