Tigriopus wannapaensis Chullasorn & Kangtia & Song & Khim 2021, sp. nov.
Creators: name: Chullasorn, Supawadee
name: Kangtia, Pawana
name: Song, Sung Joon
name: Khim, Jong Seong
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Hexanauplia
Harpacticoida
Harpacticidae
Tigriopus
Tigriopus wannapaensis

description: Tigriopus wannapaensis sp. nov.
(Figs. 10–18)
Type locality. Associated with slightly rotten green algae, Ulva clathrata, at Wannapa sandy beach in Muang district, Chonburi Province, Thailand (13°16’21.9”N, 100°55’18.4”E) on 3 June, 2017; collected by S. Chullasorn.
Specimens examined. Adult female holotype (NIBRIV0000851930) dissected on seven slides; male allotype (NIBRIV0000851931) dissected on three slides; three female and three male paratypes (NIBRIV0000851932) preserved in 95% alcohol.
Etymology. The species name refers to Wannapa Beach where the new species was found.
Description of female. Total body length of holotype 937 µm (Fig. 10A–B), measured from tip of rostrum to posterior margin of caudal ramus. Total body length of paratypes 879–1,029 µm (n = 12, mean = 957 µm). Body compact, cyclopiform ornamented with few sensilla on surface. Nauplius eye not visible. Prosome 4-segmented, comprising cephalosome fused to first pedigerous somite, and three free pedigerous somites. Cephalothorax much longer than three prosomites combined, and posterior margin smooth. Rostrum (Fig. 12A) large, slightly longer than first segment of antennule, with two pairs of sensilla; the first pair close to the rounded tip, and the second pair at halfway the rostrum length.
Urosome (Fig. 11A–B) 5-segmented, comprising P5-bearing somite, genital double-somite, two free abdominal somites, and anal somite. Genital double-somite with P6, genital field indistinct, ventrally with two genital apertures. Third and fourth urosomites with rows of spinules ventrally. Anal operculum semicircular and smooth. Caudal rami slightly longer than wide, ornamented with small spinules dorsally and ventrally. Seta I arising laterally at midlength; seta II located between seta I and seta III; seta III twice longer than seta II; seta V (Fig. 10C) longest, much longer than urosomal length; seta IV shorter than seta V; seta VI as long as seta III, located at inner distal corner; seta VII shortest, located close to insertion point of seta V.
Antennule (Fig. 12B) 9-segmented, first segment ornamented with rows of spinules on surface, second segment largest, surface of segments 2–9 smooth. Length of segments 1–2 longer than five apical segments combined. Fourth and last segment with one large and one small aesthetasc, respectively. All setae slender and naked. Armature formula: 1-(1), 2-(10), 3-(8), 4-(2 + (1 + ae)), 5-(2), 6-(3), 7-(2), 8-(2), 9-(5 + acrothek). Apical acrothek consisting of aesthetasc and two setae.
Antenna (Fig. 12C) three-segmented, comprising coxa, allobasis, and 1-segmented endopod. Coxa short, unarmed and unornamented. Allobasis bearing exopod, armed with one abexopodal smooth seta halfway inner margin, furnished with row of minute spinules on anterior surface. Exopod 3-segmented; first segment longest with two setae (one pinnate and one smooth), second segment short with one smooth seta, third segment with two smooth setae. Endopodal segment ornamented with row of minute spinules at outer distal corner, distal margin armed with smooth spines and setae: three spines, four slender setae on anterior surface, and four geniculate setae.
Mandible (Fig. 13A) with large and elongate coxa, anterior surface ornamented with one curved row of spinules, bearing well-developed gnathobase, cutting edge with eight strong overlapping teeth, and one comb-like tooth close to lateral unipinnate seta. Basis with smooth apical seta; exopod 2-segmented, first segment with two smooth setae and six spinules around distal margin, second segment with three smooth setae and two minute spines; endopod 1- segmented, with three lateral inner setae and six apical setae (four of which forming two basally fused pairs).
Maxillule (Fig. 13B). Praecoxa with some spinules, arthrite with two slender setae on surface, one slender seta and two plumose, spine-like outer elements, and five smooth, sharp apical spines. Coxa with cylindrical endite furnished with four smooth setae. Basis ornamented with four setae distally. Endopod 1-segmented with three smooth setae. Exopod 1-segmented, with one bipinnate spine and four smooth setae.
Maxilla (Fig. 13C) ornamented with row of spinules distally on outer margin and row of spinules on surface of syncoxa. Syncoxa with three endites (one praecoxal and two coxal); praecoxal endite bilobed, each lobe with two plumose distal setae; two coxal endites each with three spinulose distal setae. Basis furnished with one naked inner seta on a unipinnate strong claw and one plumose seta. Endopod 1-segmented with four slender setae and one plumose seta near base of claw.
Maxilliped (Fig. 13D) comprising syncoxa, basis, and 1-segmented endopod. Syncoxa with one unipinnate seta at inner distal corner, and many spinular rows of various length on anterior surface. Basis with rows of spinules on anterior surface and along outer margin, with some minute spinules at outer margin, and with median smooth inner seta near halfway palmar margin. Endopod represented by long smooth curved claw, almost as long as basis, and with one conical process bearing one lateral and one apical seta.
All swimming legs (Figs. 14A–B; 15A–B) biramous, P1–P4 with 3-segmented exopods and endopods. Members of each leg pair connected by simple narrow intercoxal sclerite.
P1 (Fig. 14A). Praecoxa with row of spinules on anterior surface along distal margin. Coxa rectangular, ornamented with row of spinules along outer margin. Basis with one pinnate inner spine and one smooth outer spine, with two rows of spinules on anterior surface. Endopod much shorter than exopod, both 3-segmented. Enp-1 much longer than enp-2 and enp-3 combined, with one plumose inner seta; enp-2 shorter than last segment, unarmed; enp-3 with one strong smooth outwardly curved claw and two slender inner setae. Both exp-1 and exp-2 long, exp-3 short. Exp-1 with one smooth outer seta; exp-2 with one smooth outer seta at two-thirds of outer margin, and one pinnate inner seta; exp-3 with three smooth, outwardly curved, distal spines and one inner seta.
P2 (Fig. 14B). Praecoxa small and smooth. Coxa ornamented with spinular rows of unequal length on anterior surface, and row of spinules along outer margin. Basis with one bipinnate outer spine. Endopod 3-segmented; enp-1 and enp-2 each with one plumose inner seta; enp-3 with one smooth outer spine, four plumose setae (two median and two inner). Exopod 3-segmented; exp-1 with one bipinnate outer spine and one plumose inner seta; exp-2 with one smooth outer spine and one plumose inner seta; exp-3 with three smooth outer spines, two plumose distal setae and two plumose inner setae.
P3 (Fig. 15A). Coxa ornamented with spinular rows of unequal length on anterior surface, and row of spinules along outer margin. Basis with row of spinules on surface, and some spinules at base of slender outer seta. Endopod 3-segmented; enp-1 and enp-2 each with one plumose inner seta; enp-3 with one smooth outer spine, two plumose distal setae and one plumose inner seta. Exopod 3-segmented; exp-1 and exp-2 each with one bipinnate outer spine and one plumose inner seta; exp-3 with three outer bipinnate spines, two plumose distal setae, and two plumose inner setae.
P4 (Fig. 15B). Praecoxa small and smooth. Coxa with row of spinules along outer margin. Basis with some spinules at base of slender outer seta. Endopod 3-segmented; enp-1 with one plumose inner seta; enp-2 unarmed; enp-3 with one smooth outer spine, three plumose setae (two distal and one inner). Exopod 3-segmented; exp-1 and exp-2 each with one bipinnate outer spine and one plumose inner seta; exp-3 with three bipinnate outer spines, two plumose distal setae, and two plumose inner setae.
Armature formula of swimming legs as follows (Arabic numbers represent setae, Roman numbers represent spines):
BasisExopodEndopodP1I-II-0; I-1; I.II.I0-1; 0-0; I,1,1P2I-0I-1; I-1; III,2,20-1; 0-1; I,2,2P31-0I-1; I-1: III,2,20-1; 0-1; I,2,1P41-0I-1; I-1: III,2,20-1; 0-0; I,2,1
P5 (Fig. 17B) with separate exopod and baseoendopod; with spinular row along outer margin; without intercoxal sclerite and not fused medially. Exopod ovoid with smooth (innermost) seta and four bipinnate outer setae of unequal length, second outermost longest. Baseoendopod with long and smooth outer basal seta, with five bipinnate setae, second outermost longest.
Description of male. Total body length of allotype (Fig. 16A–B) 902 µm. Total body length of paratypes 796–929 µm (n = 12, mean = 874 µm). General body shape and size similar to those of female. Sexual dimorphism expressed in antennule, antenna, P2, P5, P6 and urosomal segmentation and ornamentation.
Urosome (Fig. 18A) 6-segmented, comprising P5-bearing somite, genital somite, three abdominal somites and anal somite. Third to sixth urosomites furnished with small spinules along ventral posterior margin. Ornamentation different from female.
Antennule (Fig. 17A) subchirocer, 8-segmented with smooth setae. First segment with small spinules on anterior inner surface, fourth segment shortest, fifth segment largest, globularly expanded, with one seta and long aesthetasc, sixth segment forming claw-like outer process, seventh segment with six setae (two short and four longer) and acrothek. Armature formula: 1-(1), 2-(1), 3-(11), 4-(6), 5-(2), 6-(8 + (1 + ae)), 7-(0), 8-(7 + acrothek). Apical acrothek consisting of basally fused aesthetasc and naked seta.
P2 (Fig. 18B). Basis with one smooth outer seta. Endopod 3-segmented and modified; enp-2 with spinulose outer seta twice as long as enp-3 and distinct spiniform outer apophysis; enp-3 small, with minute, smooth, outer spine, two spinulose distal setae, and one smooth inner seta. Exopod 3-segmented; exp-1 with one smooth outer spine and one plumose inner seta; exp-2 with one bipinnate outer spine and one plumose inner seta; exp-3 with three outer spines (two bipinnate and one smooth), two plumose distal setae and two plumose inner setae.
P5 (Figs. 17C) baseoendopod bearing one smooth basal outer seta, and one smooth inner seta. Exopod oval shaped, armed with five setae of unequal length, four of which bipinnate and innermost smooth.
P6 (Fig. 18A) represented by three smooth setae unequal length.
description: Published as part of Chullasorn, Supawadee, Kangtia, Pawana, Song, Sung Joon & Khim, Jong Seong, 2021, Two new species of Tigriopus Norman, 1869 from Chonburi Province, Thailand (Crustacea: Copepoda: Harpacticidae), pp. 41-67 in Zootaxa 5051 (1) on pages 53-63, DOI: 10.11646/zootaxa.5051.1.6, http://zenodo.org/record/5564013