A new species of Remanea Klie, 1929 (Copepoda: Harpacticoida: Paramesochridae) with a redescription of the type species Author Back, Jinwook Author Lee, Wonchoel Author Huys, Rony text Journal of Natural History 2011 2011-12-31 45 47 - 48 2939 2964 http://dx.doi.org/10.1080/00222933.2011.622057 journal article 10.1080/00222933.2011.622057 1464-5262 5204903 Remanea naksanensis sp. nov. ( Figures 1–7 ) Type locality Naksan sandy beach, east coast of South Korea ( 38 ◦ 06 ′ 20 ′′ N , 128 ◦ 38 ′ 46 ′′ E ); washings of sandy sediments from a brackish water system (salinity 4–7 psu) near a small unnamed stream . Material examined Holotype female ( NIBRV0000238524 ) dissected on six slides, and paratype male ( NIBRV0000238525 ) dissected on four slides. Additional paratypes represented by 14 females ( NIBRV0000238526 ) and three males ( NIBRV0000238527 ) in ethanol. All specimens were deposited in the NIBR , Korea ; seven females and four males were used for scanning electron microscopy while 12 females were used for DNA extraction. All specimens were collected from the type locality by J. Back on 23 April 2010 . DNA-barcode (mtCOI) sequences and traces were submitted to GenBank. Description of female Body fusiform, slightly depressed dorsoventrally ( Figure 1A, B ), with sensilla as illustrated. Total body length, 553 µm ( n = 15, mean = 541 µm); largest width (153 µm) measured at posterior margin of cephalic shield. Body somites with well-developed arthrodial membranes. Cephalothorax and somites bearing P2–P4 with crenulate posterior hyaline frill. Cephalothorax bell-shaped, with several sensilla; pleural areas weakly developed, posterolateral angles rounded. Urosomites ( Figure 1A–C ), except for anal somite, with striations on hyaline frills dorsally and laterally. Fifth urosomite and anal somite without sensilla; the latter small, without anal operculum, but with well-developed flimsy serrate pseudoperculum arising from penultimate somite. Genital somite (second urosomite) and third urosomite completely fused forming genital double-somite; genital field located in posterior half of second urosomite (proximal half of genital double-somite), with copulatory pore positioned medially, and two small pores located on either side of copulatory pore. Caudal rami ( Figures 1C , 2C , 7H ) rectangular, about 1.6 times as long as wide; with three transverse spinular rows dorsally; with spinules at bases of setae III (ventrally) and VII (dorsally), and around distal margin of rami (ventrally); secretory pores located dorsally near base of seta III and ventrally near base of seta IV; with seven setae, setae I–II located halfway down the outer margin; setae III–VII located in distal third of ramus; seta II short and pinnate; seta I bare; seta III plumose; seta IV well developed and plumose, seta V longest and pinnate in distal half; seta VI pinnate; dorsal seta VII bi-articulate at base, naked. Rostrum ( Figure 1A ) well developed, with rounded tip, defined at base; with two small lateral sensilla. Antennule ( Figure 2A ) slender, eight-segmented; segment 1 with short row of long spinules along anterior margin and one pinnate seta; segments 1 and 2 similar in length; segment 4 with sub-cylindrical process bearing one bare seta fused basally to aesthetasc; armature formula: 1-[1 pinnate], 2-[7 pinnate + 1 spinulose + 3 bare], 3-[5 pinnate + 3 bare], 4-[3 pinnate + (1 + ae)], 5-[1 pinnate + 1 bare], 6-[3 pinnate + 1 spinulose + 1 bare], 7-[1 pinnate + 1 spinulose seta + bare], 8-[5 bare + (2 + ae)]. Acrothek consisting of apical aesthetasc and two basally fused bare setae. Antenna ( Figures 2B , 7A ): coxa and basis without surface ornamentation. Exopod two-segmented; exp-1 shorter than exp-2, the former with one pinnate seta distally; exp-2 with row of strong spinules apically and with four setae; armature formula: 1-[1 pinnate], 2-[3 pinnate + 1 bare]. Endopod two-segmented; enp-1 with lateral seta, without surface ornamentation; lateral armature of enp-2 consisting of two bare setae, one small spinulose element, and one pinnate seta; distal armature of enp-2 consisting of four geniculate and two bare setae (one small bare seta laterally and one long bare seta fused at base to largest geniculate seta). Figure 1. Remanea naksanensis sp. nov. Female: (A) Habitus, dorsal; (B) habitus, lateral; (C) urosome (excluding P5-bearing somite), ventral. Scale bars in µm. Figure 2. Remanea naksanensis sp. nov. Female: (A) Antennule, ventral; (B) antenna; (C) pseudoperculum, anal somite and caudal rami, dorsal (inset showing full length of setae IV–V); (D) fifth pair of legs (P5); (E) P6 and genital field. Scale bars in µm. Mandible ( Figures 3A , 7B ): coxa well developed, with process; gnathobase with six small blunt teeth and one pinnate seta at dorsal corner. Palp biramous; basis elongate, with four pinnate setae; exopod one-segmented, with three inner and two distal pinnate setae, and ornamented as figured; endopod two-segmented; enp-1 as long as enp-2, with two bare distal setae; enp-2 with seven setae (two bare setae, three distal setae fused at base, and one apical long seta and one slender bare seta confluent at base). Maxillule ( Figure 3B ): praecoxa subquadrate, without ornamentation, arthrite well developed, with five strong spines and one seta apically, three bare lateral elements, and two surface setae. Coxa with five pinnate setae. Basis with five setae. Exopod onesegmented, with four slender bare setae of different lengths and with lateral row of spinules. Endopod one-segmented, longer than exopod, with three apical, and two bare lateral setae. Maxilla ( Figure 3C ): syncoxa with four endites. First endite small, with one pinnate and one bipinnate setae; second endite with two pinnate setae; third endite with two pinnate and one bare setae; distal endite close to third endite, with one pinnate lateral seta, two pinnate distal elements, and with one small process proximally (arrowed in Figure 3C – inset 4). Allobasis with one bare seta, one stout claw-like element, and one bare accompanying seta. Endopod two-segmented; enp-1 rectangular, with five slender setae; enp-2 with one pinnate claw, two apical, and one naked lateral setae. Maxilliped ( Figures 3D , 7C ) three-segmented. Syncoxa with two rows of spinules. Basis elongate, with rows of spinules halfway down inner and outer margin. Endopod indistinctly segmented, with one bare seta proximally, one stout claw medially, two stout claw-like bi-articulate setae, and one small seta distally. P1 ( Figure 4A ): coxa and basis with spinules as figured; the latter with one outer bare and one inner pinnate seta. Exopod three-segmented, shorter than endopod; exp- 1 longest, with some spinules along outer margin and one pinnate outer spine; exp- 2 somewhat swollen distally, with one pinnate outer spine and one spinulose inner seta; exp-3 with six spines/setae. Endopod prehensile; enp-1 elongate and approximately as long as exopod, with row of spinules along outer margin and one long plumose inner seta; enp-2 small, slightly longer than wide, apically with two strong claw-like setae and one small pinnate element. P2–P4 ( Figure 4B–D ): coxae with row of long (P2) or slender (P3–P4) spinules on outer distal corner. Basis with long inner spinules and with rows of spinules on anterior surface. Exopod three-segmented; exp-1 with one strong pinnate outer spine; exp-2 shortest, with one strong pinnate outer spine and one bare inner seta; exp-3 with two pinnate outer spines, two plumose apical setae, and one bare (P2–P3) or plumose (P4) inner seta. Endopod two-segmented; enp-1 with one plumose inner seta; enp-2 as long as enp-1 (P2) or about 1.6 times as long as enp-1 (P3–P4), with one bare (P2) or pinnate (P3–P4) outer spine and two pinnate apical setae; with one pore close to inner distal corner, except for P4. Armature formula as follows: exopod: P2, 0.1.122; P3, 0.1.122; P4, 0.1.122; endopod: P2, 1.021; P3, 1.021 ( 1.020 in male); P4, 1.021. P5 ( Figures 2D , 7E ) with medially fused baseoendopods and discrete exopods. Baseoendopod with short pinnate outer basal seta; endopodal lobes shorter than exopods, each lobe with two apical pinnate setae of almost equal length, with long spinules along inner margin. Exopod well developed, with rows of spinules along inner and outer margins, with two pinnate apical setae and two spinulose short outer elements. Figure 3. Remanea naksanensis sp. nov. Female: (A) Mandible; (B) maxillule; (C) maxilla [syncoxal endites (1–4) and endopod (5) shown in separate insets; arrow indicates minute process on distal coxal endite]; (D) maxilliped. Scale bars in µm. Figure 4. Remanea naksanensis sp. nov. Female: (A) P1, anterior; (B) P2, anterior; (C) P3, anterior; (D) P4, anterior. Scale bars in µm. P6 ( Figures 2E , 7D ) represented by narrow transverse plate, armed with one bare inner seta and two pinnate outer elements of different lengths, the former longest. Description of male Slightly smaller and more slender than female, body length 498 µm ( n = 4, mean = 488 µm) ( Figure 5A ). Largest width (92 µm) measured at posterior margin of cephalic shield. Cephalothorax ( Figure 5A ) slightly more angular and with more sensilla than in female. General body shape and ornamentation as in female except for separation of genital somite; additional sexual dimorphism in antennule, P2, P3, P5 and P6. Antennule ( Figures 5B , 7F ): eight-segmented, subchirocer; segment 6 swollen, largest. Aesthetascs on sixth and eighth segments. Sixth segment with surface suture dorsoanteriorly (arrowed in Figure 7F ). Armature formula: 1-[1 pinnate], 2-[4 bare + 1 pinnate], 3-[5 bare + 3 pinnate], 4-[3 bare + 3 pinnate], 5-[2 bare + 1 pinnate], 6-[5 bare + 6 pinnate + (1 + ae)], 7-[4 bare], 8-[7 bare + (2 + ae)]. P2 ( Figure 6A ) Basis with surface spinules and small outer seta. Exopod as in female. Enp-1 as in female; enp-2 armed with two long and one small bare setae apically, the latter smaller than homologous element in female. General shape, segmentation, and armature formula as in female. P3 ( Figure 6B ). Coxa, basis, and exopod as in female. Endopod two-segmented; enp-1 with rows of long spinules along outer margin and with one inner plumose seta. Enp-2 twice as long as enp-1, with two apical setae and well developed outer apophysis. P5 ( Figure 6C ): baseoendopods confluent, forming large transverse plate; unarmed except for outer slender bare seta on either side. Exopod ovate, with row of spinules along inner margin; with two outer spinulose setae, one long apical bare seta and one small naked inner seta. P6 ( Figure 6D ): pair of P6 symmetrical, fused medially. Each P6 with one outer naked lateral seta proximally and one pinnate seta close to distal outer corner. Etymology The specific name refers to the type locality, the Naksan sandy beach area on the east coast of Korea .