Wellsopsyllus (Scottopsyllys) koreanus, Back, Jinwook & Lee, Wonchoel, 2014

Back, Jinwook & Lee, Wonchoel, 2014, Two new species of the genus Wellsopsyllus (Copepoda; Harpacticoida; Paramesochridae) from the Yellow Sea, Zootaxa 3895 (3), pp. 346-366 : 354-361

Wellsopsyllus (Scottopsyllys) koreanus sp. nov.

( Figures 7 –11)

Type locality. Gosapo Beach on the Byeonsan peninsula, on the west (Yellow Sea) coast of Korea. Coordinates: 35° 39' 51 ''N, 126° 30' 35'′E. Sediment type: sand. Salinity: 33 psu.

Material examined. Holotype, 1♀ ( MABIK CR00218011) dissected on 5 slides. Paratypes: 1♂ ( MABIK CR00218012) dissected on 4 slides, 33 ♀♀ ( MABIK CR00218013), and 3 ♂♂ ( MABIK CR00218014) preserved in 70% alcohol. October 3, 2010.

Description of female. Total body ( Figure 7 A–B) length 398 µm (measured from anterior margin of cephalic shield to posterior margin of caudal rami: n = 4, mean = 397 µm); largest width measured at posterior margin of cephalic shield: 75 µm. Body cylindrical, slightly depressed dorsoventrally; urosome gradually tapering posteriorly and with a striped distal hyaline frill.

Rostrum ( Figure 7 A–B), triangular, small, fused to cephalothorax, without sensilla; cephalothorax, bellshaped; pleural areas weakly developed and posterolateral angles rounded; posterior margin smooth.

Genital somite and first abdominal somite completely fused forming genital double-somite; copulatory pore ( Figure 10 B) well developed with a small process sub-distally. P6 ( Figure 10 B), represented by a flat plate, each side with 3 bare setae. Penultimate somite ( Figure 7 A) with a developed, rounded pseudoperculum. Anal somite cleft deeply dorsally.

CR ( Figure 7 C): juxtaposed, conical, approximately 3.8 times as long as greatest width, distal margin blunt. Each ramus armed with 6 setae; seta I not observed and probably vestigial; seta II bare; setae III pinnate; seta IV short and pinnate; seta V consisting of a stout spine-like base with a long cylindrical seta-like portion arising subdistally; seta VI shortest and bare; seta VII bi-articulate at base and arising from inner dorsal surface; all setae displaced onto dorsal surface of ramus.

A1 (Figure 11B), 8-segmented, short, robust; segment-4 with a sub-cylindrical process armed with a long slender seta fused basally to aesthetasc; segment-6 armed with 1 slender bare seta arising from a ventral subcylindrical process. Armature formula: 1-[1 bare], 2-[8 bare + 1 pinnate], 3-[4 bare + 2 pinnate], 4-[1 bare + 1 pinnate + (1 + ae)], 5-[1 bare], 6-[3 bare], 7-[2 bare], 8-[4 bare + acrothek]; apical acrothek consisting of a welldeveloped aesthetasc fused basally to 2 slender, naked setae.

A2 ( Figure 8 A), 4-segmented, comprising coxa, basis, and 2-segmented free enp coxa small and bare; basis approximately 2.5 times as long as wide, without any surface ornamentation; enp-1 with 1 pinnate abexopodal seta; enp-2 armed with 1 lateral bare seta, 2 bare spines sub-distally, 4 geniculate setae distally, and 1 long geniculate seta fused basally to 1 long bare seta; exp 1-segmented, with 1 pinnate and 1 bare inner setae, 1 distal modified seta, and 1 small outer bare seta distally.

Mandible ( Figure 8 B), coxa with well-developed gnathobase bearing 1 small bare seta at dorsal corner, 7 major overlapping teeth; palp biramous, comprising basis, 1-segmented exp, and 2-segmented enp; basis widened distally, with 2 pinnate setae; exp with 2 lateral and 2 distal bare setae; enp 2.3 times as long as than exp; enp-1 longer than enp-2; the former with 2 bare sub-distal setae; enp-2 with 6 basally fused bare setae at apex.

Maxillule ( Figure 8 C), praecoxal arthrite well developed, with 7 spines, 2 bare, and 2 juxtaposed slender setae; coxa with a cylindrical endite bearing 2 bare and 1 pinnate setae apically; basis fused with a cylindrical endite with 6 naked setae distally; exp 1-segmented, small, with 2 pinnate setae; enp 1-segmented, elongate, with 3 lateral and 2 distal bare setae.

Maxilla ( Figure 8 D), syncoxa with 3 cylindrical endites; praecoxal endite with 1 pinnate and 2 bare setae; proximal endite with 1 pinnate and 1 bare setae on distal margin; distal coxal endite with 2 pinnate setae; allobasis with 1 strong claw, 2 accessory bare setae and 1 bare seta near base of enp; enp 1-segmented, with 4 bare and 1 pinnate setae distally.

Maxilliped ( Figure 8 E), 4-segmented, comprising syncoxa, basis, and 2-segmented enp; syncoxa with 1 bare seta; basis ornamented with a row of spinules sub-distally; enp-1 with 2 lateral bare setae and 1 geniculate seta distally; enp-2 with 2 geniculate setae.

P1 (Figure 9A), coxa bare; basis with 1 bare outer seta and ornamented with an unusual bundle of 5 very long setules near inner margin and 1 row of spinules; exp-1 approximately 2.2 times longer than exp-2, the former with 1 long pinnate seta and ornamented with two row of spinules; exp-2 short, with 4 long pinnate setae distally; enp prehensile; enp-1 elongate, ornamented with a row of outer spinules; enp-2 with 2 geniculate setae apically.

P2–P3 (Figure 9B–C), coxa bare; basis with 3 rows of spinules as illustrated and with 1 basal outer seta; exp 3- segmented; exp-1 and exp-2 with 1 outer; exp-3 with 1 outer spine and 1 geniculate apical seta; enp 1-segmented, without armature.

FIGURE 9. Wellsopsyllus (Scottopsyllus) koreanus sp. nov., female: (A) P1; (B) P2; (C) P3; (D) P4.

FIGURE 11. Wellsopsyllus (Scottopsyllus) koreanus sp. nov.: (A) malem, habitus, dorsal; (B) femalem, antennule; (C) malem, antennules, C1: segments 1 to 4 [incomplete surface suture arrowed]; C2: segments 5 to 7.

P4 (Figure 9D), coxa bare; basis with 1 naked basal outer seta and ornamented with 3 rows of spinules; exp 3- segmented; exp-1 and exp-2 with 1 outer spine; exp-3 with 1 outer spine and 1 geniculate seta; enp 2-segmented; enp-1 ornamented with a row of outer spinules; enp-2 with 1 modified seta.

The armature formula is as follows:

P5 ( Figure 10 A), with benp medially fused; benp with 1 basal seta; endopodal lobe dimpled, each leg with 2 bare setae on outermost process; exp discrete, small, with 3 bare setae.

Description of male. Body (Figure 11A), slightly smaller and more slender than female, body length 375 µm (measured from anterior margin of cephalic shield to posterior margin of caudal rami: n = 8, mean = 370 µm), largest width measured at posterior margin of cephalic shield: 70 µm; general body shape and ornamentation as in female except for separation of genital somite; additional sexual dimorphism in A1, P5, and P6.

A1 (Figure 11C1–C2), 7-segmented, subchirocer; segment-2 formed from fusion of two ancestral segments as indicated by incomplete surface suture (denoted by an arrow in Figure 11C1), with a sub-cylindrical process armed with 1 long slender seta; segment-5 swollen, largest. Armature formula: 1–[1 bare], 2–[6 bare + 2 pinnate], 3–[5 bare + 1 pinnate], 4–[1 bare + 1 pinnate], 5–[6 bare + 1 modified stout + (1 + ae)], 6–[2 bare], 7–[8 bare + acrothek]; apical acrothek consisting of small aesthetasc fused basally to 2 bare setae.

P5 ( Figure 10 C), both legs confluent; benp with 1 bare basal seta; endopodal lobe ridged, with 2 bare setae on each side; exp discrete, with 3 bare setae.

P6 ( Figure 10 D), pair of P6 symmetrical, with 3 bare setae.

Etymology. The specific name ‘ koreanus ’ refers to the nation to which the type locality belongs.

Figures

FIGURE 7. Wellsopsyllus (Scottopsyllus) koreanus sp. nov., female: (A) habitus, dorsal; (B) habitus, lateral; (C) left caudal rami, dorsal.

FIGURE 8. Wellsopsyllus (Scottopsyllus) koreanus sp. nov., female: (A) antenna; (B) mandible; (C) maxillule; (D) maxilla; (E) maxilliped.

FIGURE 10. Wellsopsyllus (Scottopsyllus) koreanus sp. nov.: (A) female P 5; (B) female genital double-somite, ventral; (C) male P 5; (D) male P 6.