Kushia zosteraphila Harris V.A. & Iwasaki, 1996

Lee, Seunghan, Kim, Jaehyun & Lee, Wonchoel, 2023, New record of the family Porcellidiidae Boeck, 1865 (Harpacticoida, Copepoda) in Korea, Journal of Species Research 12 (1), pp. 27-37 : 28-35

Kushia zosteraphila Harris V.A. & Iwasaki, 1996

( Figs. 1-6 )

Kushia zosteraphila Harris V.A. & Iwasaki, 1996b , P. 205 - 208, Figs. 3 , 6A, B , 7C, D .

Material examined. 2$$ ( MABIK CR00252831 , CR00252832 ) and 1♂ ( MABIK CR00252833 ) from the intertidal region (35°16′9.43″N, 129°14′36.70″E) of Gijang-gun, Busan on 7 May 2020. Eight individuals (5$$, 3♂ ♂) from same locality were used for length measurement. DNA-barcode (mtCOI) sequence and trace were submitted to GenBank (OP825029 - OP825036, 658 bp) .

Description of female. Four transverse bands of dark red-brown at the body segment (cephalosome, metasome, and urosome). Total body length 1,002 - 1,102 μm (mean± SD =1,049± 37 μm, n = 5) as measured from the anterior margin of cephalosome to the posterior margin of the caudal rami. Dorsal pit present on prosome, urosome, P5 and CR ( Fig. 6A ). Body surface armed with some sensilla ( Fig. 1A ).

Prosome ( Figs. 1A , 6A ) four-segmented; comprising cephalosome and three free pedigerous somites. P1-bearing somite fused to cephalosome. Hyaline membrane present on lateral margin. Rostrum reversed triangular shaped, protrudes beyond the anterior margin of cephalosome.

Urosome ( Figs. 1A , 2B ) three-segmented, comprising the P5 somite, genital double somite and anal somite. Most of the anal somite is dorsally covered by genital double somite.

Caudal ramus ( Figs. 1A , 2B, C , 6C ) pentagonal; inner edge straight and longer than outer edge; distal edge bevelled at an outer corner; seta VII and I closed, inserted at proximal half; seta II small on bevelled edge; seta III annulate, inserted ventrally along bevelled edge; terminal seta IV, V and VI pinnate. Terminal fringe of fine setules present.

Antennule ( Fig. 1B ) six-segmented. Aesthetascs on segment 4 and 6. Armature formula: 1-[1], 2-[11], 3-[9], 4-[6 +ae], 5-[5], 6-[11 + ae].

Antenna ( Fig. 2A ) four-segmented, comprising with coxa, basis, and two-segmented endopod. Coxa short. Basis with spinules on the medial surface and a distal end. Exopod with three lateral and three distal setae. Enp-1 with spinules along of lateral margin; enp-2 with many spinules on the surface, four lateral setae, two annulate distal; three geniculate setae; one thick and denticulate setae.

Mandible ( Fig. 3A ) with small coxa and gnathobase. Endopod with four pilous and thick setae on the anterior lobe; five pilous and thick setae, and one slender seta on the posterior lobe. Exopod one-segmented, with six pilous and thick setae, and three slender setae.

Maxillule ( Fig. 3B ) with nine plumose and two naked setae on arthrite. Coxa with five setae and spinules on coxal endite. Basis with two endites and four setae on each. Endopod with six plumose setae. Exopod with one plumose seta and spinules on distal margin.

Maxilla ( Fig. 3C ) with syncoxa having two endites with five setae and two setae, respectively. Allobasis with three setae on the distal corner: one small slender, one thick and denticulate, and one spinulose seta. Endopod one-segmented, with two denticulate and two spinulose setae.

Maxilliped ( Fig. 3D ) with long hairs on the margin of syncoxa and basis. Syncoxa with one naked seta on the distal surface. Basis with the protruding and plumose process. Endopod two-segmented; enp-1 with one small seta and one thick seta; enp-2 with two thick setae.

P1 ( Fig. 4A ). Basis with one swollen and pilous seta. Endopod two-segmented; enp-1 large and triangular shape, with a seta on proximal inner margin; enp-2 with two thick claws distally. Exopod three-segmented; exp-1 with a swollen pilous outer seta; exp-2 with a swollen pilous outer seta; exp-3 with a plumose seta on the proximal inner margin, three swollen pilous setae on the outer margin, one annulate and one swollen pilous seta on distal margin.

P2 ( Fig. 4B ). Basis shorter than wide, with slender outer seta and spinules on the outer lateral margin. Endopod three-segmented and longer than exopod; enp-1 with hairs and a row of spinules along the outer lateral margin, with one plumose inner seta; enp-2 with hairs along the outer margin, spinules on middle anterior surface, with two plumose inner setae; enp-3 with rows of spinules on the proximal and distal anterior surface, with one pinnate inner seta, two plumose distal setae, and one plumose outer seta. Exopod three-segmented and reaching to distal margin of enp-1; exp-1 with two rows of spinules along the outer lateral margin, with one plumose inner seta and one plumose outer seta; exp-2 with a row of spinules along the outer lateral margin, with one plumose inner seta and one pinnate outer spine; exp-3 with a row of spinules on proximal lateral margin, with two plumose inner setae, two plumose distal setae, and three pinnate outer spines.

P3 ( Fig. 4C ). Intercoxal sclerite wide. Coxa broad. Basis shorter than wide and located on coxa, with slender outer seta and spinules on outer lateral margin. Endopod three-segmented and shorter than exopod, reaching almost proximal half of exp-3; enp-1 with a row of spinules along the outer margin, with one plumose inner seta; enp-2 with a row of spinules along the outer margin, with one pinnate inner seta, one plumose inner seta, and one naked outer seta; enp-3 with rows of spinules along the outer margin and proximal surface, with one plumose inner seta and one pinnate inner seta, two plumose distal setae, and one plumose outer seta. Exopod three-segmented; exp-1 with a row of spinules along the outer margin, with one plumose inner seta and one naked outer seta; exp-2 with rows of spinules along the outer margin and posterior surface, with one plumose inner seta and one naked outer spine; exp-3 with rows of spinules on proximal lateral margin and posterior surface, with three plumose inner setae, two plumose distal setae, and three naked outer spines.

P4 ( Fig. 4D ). Intercoxal sclerite wide. Coxa broad. Basis shorter than wide and located on coxa, with slender outer seta and spinules on the outer margin. Endopod three-segmented and shorter than exopod, reaching to distal margin of exp-2; enp-1 with two rows of spinules along the outer margin and posterior surface, with one plumose inner seta; enp-2 with a row of spinules along the outer margin, with one pinnate inner seta; enp-3 with a row of spinules along the outer margin, with one pinnate inner seta, two plumose distal setae, and one plumose outer seta. Exopod three-segmented; exp-1 with two rows of spinules along the outer margin, with one plumose inner seta and one pinnate outer spine; exp-2 with rows of spinules on lateral margin and posterior surface, with one plumose inner seta and one pinnate outer spine; exp-3 with rows of spinules on lateral margin and posterior surface, with three plumose inner setae, two plumose distal setae, and three pinnate outer spines.

Armature formula for swimming legs:

Exopod Endopod P1 0.0.123 1.2

P2 1.1.223 1.2.121 P3 1.1.323 1.2.221 P4 1.1.323 1.1.121 P5 ( Fig. 2D ). Baseoendopod with two distal setae each on the dorsal and ventral surface. Exopod forming keeled plate, tapering distally; a row of spinule along outer margin; exopod with five setae, one plumose seta on the mediolateral margin, four setae on the distal half surface (distal seta 1 as long as seta 2 and 3; distal seta 4 shortest).

Description of male. Total body length 860 - 870 μm (mean± SD = 863± 6 μm, n = 3) as measured from the anterior margin of cephalosome to the posterior margin of the caudal rami. Dorsal pit present on prosome, urosome, P5 and CR ( Fig. 6B ). Body surface armed with some sensilla ( Fig. 5A ).

Prosome ( Figs. 5A , 6B ) four-segmented; comprising cephalosome and three free pedigerous somites. P1-bearing somite fused to cephalosome. Hyaline membrane present on lateral margin.

Urosome ( Fig. 5D ) three-segmented, comprising the P5 somite, genital somite and anal somite. Caudal ramus almost quadrate, without bevelled lateral edge. Seta III annulate and inserted on distal margin.

Sexual dimorphism in A1, P2, and P5.

Antennule ( Fig. 5B ) four-segmented. Aesthetasc on segment 3 and 4. 3rd segment with conspicuous comb on the accessory lobe, proximal coupling denticle with a double serrated edge. Armature formula: 1-[1], 2-[11], 3-[15 + ae], 4-[11 + ae]. Most of setae annulate.

P2 ( Fig. 5C ) exopod as in female. Endopod three-segmented and longer than exopod, with hairs along the outer margin of each segment; enp-1 with one plumose inner seta; enp-2 with two plumose inner setae; enp-3 with two plumose distal setae.

P5 ( Fig. 5D ) with six short and pinnate setae on the distal margin; rows of spinules on the ventral surface.

Figures

Fig. 1. Kushia zosteraphila. Female.A: Habitus, dorsal; B. Antennule. Scale bar in μm.

Fig. 2. Kushia zosteraphila. Female.A:Antenna; B: Urosome, ventral; C: Caudal rami; D: P5, numbered setae indicate distal setae from the most proximal to the distal. Scale bar in μm.

Fig. 3. Kushia zosteraphila. Female.A: Mandible; B: Maxillule; C: Maxilla; D: Maxilliped. Scale bar in μm.

Fig. 4. Kushia zosteraphila. Female.A: P1; B: P2; C: P3; D: P4. Scale bar in μm.

Fig. 5. Kushia zosteraphila. Male:A: Habitus, dorsal; B: Antennule; C: P2; D: Urosome, dorsal. Scale bar in μm.

Fig. 6. Kushia zosteraphila. Scanning electron micrographs.A: Female, habitus; B: Male, habitus; C: Female, caudal rami, ventral view; D: Male, maxilla. Scale bar in μm.

Fig. 7. Reported localities of Porcellidiid species in Korea. 1. Wando; 2. Dolsando; 3. Maemuldo; 4. Haeundae; 5. Gijang; 6. Gori; 7. Guryongpo; 8. Weolpo; 9. Gangneung; 10. Namae; 11. Ulleungdo; 12. Dokdo; 13. Chujado; 14. Hanrim; 15. Munseom.