Nannopus serratus, Vakati, Vinod & Lee Wonchoel, 2017

Vakati, Vinod & Lee Wonchoel, 2017, Five new species of the genus Nannopus (Copepoda: Harpacticoida: Nannopodidae) from intertidal mudflats of the Korean West Coast (Yellow Sea), Zootaxa 4360 (1), pp. 1-66 : 22-31

publication ID	https://doi.org/ 10.11646/zootaxa.4360.1.1
publication LSID	lsid:zoobank.org:pub:D7ABA95B-5F41-42EB-94FA-1105489C5C34
DOI	https://doi.org/10.5281/zenodo.6024255
persistent identifier	https://treatment.plazi.org/id/8B0AA13A-FFB6-FFEA-A6C8-F999A9BDFE53
treatment provided by	Plazi
scientific name	Nannopus serratus
status	sp. nov.

Treatment

Nannopus serratus sp. nov.

( Figs. 16–22 View FIGURE 16 View FIGURE 17 View FIGURE 18 View FIGURE 19 View FIGURE 20 View FIGURE21 View FIGURE 22 )

Type locality. Intertidal mudflat, Gilsang-myeon , Ganghwa Island, South Korea, Yellow Sea, 37°35'55.9"N 126°30'49.2"E ( Fig. 1A, B View FIGURE 1 ). GoogleMaps

Type material. Holotype: 1 female in 70% ethanol (NIBRIV0000753985). Allotype: 1 male in 70% ethanol (NIBRIV0000810841). Paratypes: 2 females dissected on 5 and 2 slides (NIBRIV0000810838 – 39), 2 males dissected on 1 and 1 slides (NIBRIV0000810842 – 43); 2 females and 1 male on SEM stub (NIBRIV0000810840). All samples were collected by Vinod Vakati, 20 November 2013.

Etymology. The species epithet is derived from the Latin “ serratus ” referring to the strong bipinnate spines on the antennary endopod, and outer exopodal spines of P1–P 4 in both sexes.

Description of female (based on holotype and paratypes). Body fusiform ( Fig. 16A, B View FIGURE 16 ) narrow, total body length ranged from 556 to 566 µm (mean = 562 µm, n = 3; holotype: 566 µm, measured from tip of rostrum to posterior margin of caudal rami). Maximum width ranged from 166 to 173 µm (mean 169 µm, n = 3; holotype: 166 µm, measured at posterior margin of cephalothorax). Body slightly slender, tapering towards posterior, and inner cuticle relatively thicker. Urosome/prosome length ratio 0.73 ( Fig. 16A View FIGURE 16 ) and body length/width ratio about 3.4. Body ornamentation ( Figs. 17A–F View FIGURE 17 , 19A–D View FIGURE 19 ) almost as in N. minutus except for denticles arranged in unique pattern of patches on cephalothorax and anal somite. Each urosomite with rows of slim setules ventrally ( Fig. 17F View FIGURE 17 ). Cephalothorax ( Fig. 16A View FIGURE 16 ) bell shaped, slightly narrow, 0.8 times as wide as long, comprising 31% of total body length, with several paired sensilla, and serrated posterior margin.

Rostrum ( Fig. 16B, C View FIGURE 16 ) prominent, deeply recurved downward than in N. minutus , anterior margin densely hirsute, and with 1 pair of dorsal sensilla (not visible in dorsal view).

Prosome ( Fig. 16A, B View FIGURE 16 ) 4-segmented, comprising cephalothorax and 3 subequal free pedigerous somites. P2- bearing somite with 2 long medial sensilla dorsally, posterior margins of prosomites serrated, and with few sensilla as figured.

Urosome ( Figs. 16A, B View FIGURE 16 , 17E View FIGURE 17 , 20A View FIGURE 20 ) 5-segmented, comprising P5-bearing somite, genital double-somite, 2 free abdominal somites and anal somite. Posterior margins of urosomites serrated dorsally and ventrally. Posterior margin of genital double-somite and following somite with pair of strong sensilla ventrally (arrowed in Fig 20A View FIGURE 20 ). Each somite with transverse row of spinules along posterior margin ventrally. Lateral margin of second to fourth urosomites with small projection ( Figs. 16B View FIGURE 16 , arrowed in 17E).

Genital double-somite ( Fig. 20A View FIGURE 20 ) 1.6 times as wide as long, completely fused ventrally, clearly distinct dorsally, with serrated dorsal posterior margin, copulatory pore located between both P6, and with slight median depression.

Anal somite ( Figs. 19A–D View FIGURE 19 , 20A, C View FIGURE 20 ) almost as long as width with unique pattern of surface ornamentation dorsally and ventrally.

Caudal rami ( Figs. 19A–D View FIGURE 19 , 20A–C View FIGURE 20 ) square (dorsally) or sub-cylindrical (ventrally) shaped, as long as wide (in dorsal view), twice as long as wide (in ventral view), and with row of spinules along posteroventral margins. Caudal ramus bearing 7 setae: seta I pinnate, shorter than ramus width, and located anterolaterally; seta II pinnate, almost as long as ramus length, and inserted anterolaterally midway along outer margin; seta III pinnate, as long as ramus length, and inserted anterolaterally midway along outer margin; seta IV slender, bipinnate, 0.4 times as long as seta V, located at outer posterior margin, and wide at proximal region; seta V strongest, bipinnate with proximal part rather wide and smooth, and located at inner posterior margin; seta VI pinnate, small, and located at inner posterior corner; seta VII slender, flexible, triarticulate, pinnate, located midway along inner margin, and relatively longer than in N. minutus .

Antennule, maxillule, maxilla, and maxilliped as in N. minutus .

Antenna ( Fig. 16D View FIGURE 16 ) same as in N. minutus except for endopod with few spinules at outer distal corner, spines rigid and blunt than in N. minutus . All distal spines denticulated except for inner subdistal spine. Exopod 1.3 times as long as width, and with 4 naked elements.

Mandible ( Fig.16E View FIGURE 16 ) same as in N. minutus except for mandibular palp with 1 basal (pinnate), 1 endopodal (naked seta arising from stem like protrusion), and 3 exopodal elements (2 pinnate and 1 naked).

P1–P4 ( Fig. 18A–E View FIGURE 18 ) with smooth and short concave intercoxal sclerite (not illustrated). Praecoxa somewhat triangular and shorter than coxa, distal margin smooth (P2, P3 and P4) or ornamented with 1 row of spinules (P1). Coxa with 1 spinular row on anterior surface and with 1 row of strong outer spinules. Basis with 1 row of strong outer spinules near insertion of exopod, and 1 row of distal spinules near insertion of endopod except for P4. P1 with row of distal spinules near insertion of inner spine. Basal outer seta naked (P1, P2 and P4) or bipinnate (P3), and inner pinnate spine present on P1. Exopod 3-segmented, and all segments subequal in length. Each exopodal segment with robust outer spinules except for P3 exp-3. Exp-1 to -3 (P1 and P2) and exp-1 to -2 (P4) with row of inner setules. P2 and P3 exp-2 with pinnate inner setae. Exp-3 (P1, P2, P3 and P4) with pinnate inner subdistal, distal, and outer terminal setae. P4 exp-3 with 1 inner subdistal pectinate seta. Endopod 1-segmented in P1 and P4 or 2-segmented in P2 and P3. P1 endopod, P2 enp-2 and P3 enp-1 with robust outer distal spinules. P1 endopod with inner setules. All endopodal setae on P1–P4 pinnate except for naked inner short seta on P4 endopod ( Fig. 18E View FIGURE 18 ). Armature formula as follows:

P5 ( Fig. 20D View FIGURE 20 ) with separate baseoendopod and exopod. Baseoendopod transversely elongated, confluent with somite, almost rectangular, and scattered setules along anterior surface. Endopodal lobe with 1 pectinate and 2 bipinnate setae. Exopod squarish, almost as long as width, and with rows of setules and 4 pinnate setae (innermost element longest, strongest, bipinnate and fused to exopod).

P6 ( Fig. 20A, E View FIGURE 20 ) linguiform and outer distal edge bearing 1 pinnate seta.

Description of male (based on allotype and paratypes). Body ( Fig. 21A View FIGURE21 ) as in female except for total body length ranged from 492 to 594 µm (mean = 538 µm, n = 2; allotype: 528 µm, measured from tip of rostrum to posterior margin of caudal rami). Maximum width ranged from 163 to 178 µm (mean 171 µm, n = 2; allotype: 172 µm, measured at posterior margin of cephalothorax). Urosome/prosome length ratio 0.86 ( Fig. 21A View FIGURE21 ) and body length/width ratio about 3.7. Cephalothorax ( Fig. 21A View FIGURE21 ) as in female except for 1.1 times as long as wide and comprising 30.7% of total body length. Body ornamentation (not illustrated), anal somite ( Fig. 21A View FIGURE21 ), caudal rami ( Fig. 21A–D View FIGURE21 ), rostrum (not illustrated), antenna (not illustrated), mandible (not illustrated), P1 and P4 (not illustrated) as in female. Antennule (not illustrated) as in male N. minutus and remaining mouth parts (not illustrated) as in N. minutus .

Prosome 4-segmented ( Fig. 21A View FIGURE21 ), comprising cephalothorax (bearing first pedigerous somite), and 3 free somites. Posterior margin of prosomites serrated and with sensilla as in female except for second prosomite without long sensilla.

Urosome 6-segmented ( Fig. 21A, B View FIGURE21 ), comprising P5-bearing somite, genital somite, 3 free abdominal somites, and anal somite. Posterior margin of urosomites serrated except for anal somite, and with sensilla as in female. Urosomite 3 to 5 with longitudinal row of spinules along posterior ventral margin.

Genital somite ( Fig. 21B View FIGURE21 ) homologous to anterior part of genital double-somite in female, and second and third urosomites clearly segmented ventrally.

P2–P3 ( Fig. 22A, B View FIGURE 22 ) with smooth and short concave intercoxal sclerite (not illustrated). Exopod 3-segmented. P2 exopod more robust than in female and P2 exp-3 outer spines stronger than in female (arrowed in Fig. 22A View FIGURE 22 ). P3 exopod as in female except for exp-3 with outer spinules. P3 enp-1 without outer spinules. P3 enp-2 modified with outer spine fused to segment forming bipinnate apophysis, 1 short naked inner, and 1 long pinnate distal setae.

P5 ( Fig. 22C View FIGURE 22 ) baseoendopod confluent with somite. Endopod with 1 pectinate and 2 naked setae (arrowed in Fig. 22C View FIGURE 22 ). Exopod fused with baseoendopod bearing 4 elements (3 pinnate and 1 naked), and 2 medial setae subequal in length (arrowed in Fig. 22C View FIGURE 22 ).

P6 ( Figs. 21B View FIGURE21 , 22D View FIGURE 22 ) asymmetrical with simple operational flap at left side and each flap with 2 short naked setae.