Species Card of Copepod
Calanoida ( Order )
    Diaptomoidea ( Superfamily )
        Pontellidae ( Family )
            Labidocera ( Genus )
Labidocera churaumi  Hirabayashi, 2014   (F,M)
Hirabayashi & S. Ohtsuka , 2014 (p.21, Descr. F, M, figs. F,M, Rem.)
Species Labidocera churaumi - Plate 1 of morphological figuresIssued from : T. Hirabayashi & S. Ohtsuka in ZooKeys, 2014, 447. [p.23, Fig. 1].
Female (from Tokashiki Island: Okinawa) A-B, habitus (dorsal and lateral, respectively); C, anterior part of cephalosome (lateral); D, urosome with outline of attached spermatophore and coupler (dorsal); E, left A1; F, A2.

Ratio of prosome to urosome lengths 4 : 1.
- Prosome length to width ratio 2.85 : 1.
- Cephalic profile rounded in dorsal view, without lateral hooks.
- Paired dorsal eyes with cuticular lenses; protuberant ventral eye extending anteroventrally between rostral processes.
- Rostrum bifid, directed posteroventrally.
- Posterior margins of prosome almost symmetrical in dorsal view, tapering to simple abbreviated, pointed process at each lateral corner.
- Urosome 2-segmented, of characteristic shape.
- Genital compound somite strongly asymmetrical; anterior left surface with posteriorly-directed rod-like process and posterior right smoothly rounded.
- Spermatophore attached dorsally to genital somite.
- A1 23-segmented; larger and longer setae on segments 3-6.
- A2 biramious: coxa with short plumose distal seta; basis and 1st endopodal segment fused to form elongate allobasis, setation formula 2, 2. Compound distal endopodal segment with 9 and 7 setae on proximal and distal lobes, respectively; exopod 5-segmented, setal formula 0, 0, 2, 2, 3.

Species Labidocera churaumi - Plate 2 of morphological figuresIssued from : T. Hirabayashi & S. Ohtsuka in ZooKeys, 2014, 447. [p.25, Fig. 2].
Female: A, Md; B, Mx1; C, Mx2; D, Mxp.

- Md with wide, heavily chitinized gnathobase; mandibular palp biramous, basis robust, armed with 4 inner setae; endopod 2-segmented, 1st segment armed with 1 short and 3 long setae, 2nd segment with 7 terminal setae; exopod 2-segmented, 1st segment unarmed, 2nd segment with 6 terminal setae; mandibular gnathobase distal edge bearing 8 teeth comprising: from ventral margin 1 apical, 1 subapical, 3 compound medial, and 3 basal; medial teeth with bifurcated cusps; dorsal end of gnathobase with 1 seta.
- Mx1 praecoxal arthrite with 15 setal elements, 4 on posterior surface; coxal endite with 2 long and 1 short elements, and 9 setae on epipodite; basis with 3 setae on proximal and distal endites; 1 large seta on basal exite; proximal endopod segment and endopod segment 2 incorporated into basis, proximal endopod segments with 2 setae, endopod segment 2 with 2 setae and distal endopod segment with 5 apical setae; exopod with 10 setae.
- Mx2 with 1st praecoxal endite bearing 6 setae, 2nd with 3 setae; coxa with 3 setae each on proximal and distal endites; basis with 3 setae; endopod 3-segmented, setal formula 1, 1, 4.
- Mxp with praecoxa and coxa fused, 3 syncoxal endites well developed, setal formula 2, 2, 4; endite setae strong, spinulose; basis fringed with medial row of spiniform processes and 2 distal setae; endopod 4-segmented, setal formula 2, 1, 1, 2.

Species Labidocera churaumi - Plate 3 of morphological figuresIssued from : T. Hirabayashi & S. Ohtsuka in ZooKeys, 2014, 447. [p.27, Fig. 3].
Female: A, P1; B, P2; C, P3; D, P4; E, P5.

- P5 biramous, slightly asymmetrical; coxa and intercoxal sclerite fused; basis subrectangular, with posterior seta; endopod rounded distally, about 0.3 times as long as exopod; exopods of both legs 1-segmented, bifurcated tip and with 2 outer spines; outer process on left slightly larger than right and with small spine-like process on proximal part.

Species Labidocera churaumi - Plate 4 of morphological figuresIssued from : T. Hirabayashi & S. Ohtsuka in ZooKeys, 2014, 447. [p.26].
Female and Male: Armature formula of the swimming legs P1-P4 (Arabic numerals : setae; Roman numerals : spines)

Species Labidocera churaumi - Plate 5 of morphological figuresIssued from : T. Hirabayashi & S. Ohtsuka in ZooKeys, 2014, 447. [p.28, Fig. 4].
Male: A-B, habitus (dorsal and lateral, respectively); C, right A1; D, P5.

- Prosome about 4 times as long as urosome.
- Urosome symmetrical with 5 somites.
- Anal somite asymmetrical.
- Caudal rami asymmetrical.
- Right A1 15-segmented, geniculate between segments 11 and 12, reaching middle of 3rd pedigerous somite; segments 11 and 12 with row of teeth. Left A1 as in female.
- A2, mouthparts and swimming legs as in female.
- P5 asymmetrical. Left P5 short, intercoxal sclerite and left coxa fused; basis cylindrical with seta near base; exopod 2-segmented, 1st segment cylindrical,2nd segment triangular, short, with protruding hairy medial surface and 3 distal and 1 lateral spines, one of them long. Right P5 basis with seta; exopod 2-segmented, forming chela; thumb of chela large, triangular, arising near base of 1st exopodal segment; 1st exopodal segment with 2 small setae, 2nd exopodal segment elongate and curved, with 3 slender marginal setae

NZ: 1

Distribution map of Labidocera churaumi by geographical zones
NW Pacif. (Tokasshiki Port, Tokashiki Island, Okinawa)
N: 1
(1210) F: 2,225-2,790; M: 1,0819-2,531; {F: 2,225-2,79; M: 1,081-2,531}
Rem.: For Hirabayashi & Ohtsuka (2014, p.26) the species is similar to L. madurae Scott, 1909 and L. tasmanica Taw, 1974. These three species constitute a species group within the L. detruncata species complex (see key to Indo-West Pacific species groups in Labidocera detruncata species complex in Labidocera Genus). These three species have a restricted distribution in the subtropical and tropical , coastal waters of the Indo-West Pacific, and are referred by the authors as L. madurae species group (see key of the species in this group).
Last update : 19/07/2021
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Razouls C., Desreumaux N., Kouwenberg J. and de Bovée F., 2005-2024. - Biodiversity of Marine Planktonic Copepods (morphology, geographical distribution and biological data). Sorbonne University, CNRS. Available at http://copepodes.obs-banyuls.fr/en [Accessed June 24, 2024]

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