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Marine Planktonic Copepods
Acartia (Odontacartia) edentata  Srinui, Ohtsuka & Metillo, 2019   (F,M)
Taxonomy
Order Calanoida
Superfamily Diaptomoidea
Family Acartiidae
Sub-Genus Odontacartia

Synonymy

Acartia (Odontacartia) pacifica sensu lato

References

Srinui & al., 2019 (p.71, Descr. F, M, figs.M, fig.1, mol. biol, phylogeny, fig.7: range t° & Sal., key: p.89, 90); Lee S. & al., 2019 (p.86, Table 3).

Figures

Plate 1 Remark: Erratum concerning the name: read Srinui and not Siruani.
Female:
1 - Genital double-somite lacking posterodorsal sharp processes.
2 - Ventroposterior corners of prosome acutely pointed, reaching beyond half of ventral double-somite.

Male:
1 - Urosomite 3 with large spine-like processes dorsally.
2 - Dorsal processes of urosomite 3 long, reaching half-length of anal somite.
3 - Urosomite 4 lacking spine-like processes between pair of dorsal processes.
4 - Genital somite with spinular rows along posterodorsal border.
5 - Inner projection of 1st exopodal segment of right P5 irregularly triangular.
Plate 2 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.83,Table 2]
Morphological characteristics in Acartia (Odontacartia) edentata.
Compare with A. (O.) pacifica and A. (O.) ohtsukai, closely related species.
Plate 3 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.76, Fig.2].
Female (from 11°30'70''N, 124°69'01''E): A-B, habitus (dorsal and lateral, respectively); C, A1 (Roman numerals denote ancestral segment numbers); D, A2; E, Mx1; F, Mxp.

Nota:
- Cephalosome and 1st pediger separate, 4th and 5th pedigers fused.
- Anterior margin of cephalosome triangular in dorsal view.
- Rostrum with pair of thick, strong and sharp filaments.
- Posterior prosome symmetrical with with pair of acute processes on each side: large ventrolateral, pointed processes with pair of small prrominences between and pair of smaller, pointed processes dorsally.
- Urosome of 3 free somiyes.
- Genital double-somite symmetrical with ratio of width-length approximately 1 : 1, lacking posterodorsal pointed processes.
- 2nd urosomite with pair of strong, posterodorsal, pointed processes.
- Anal somite as wide as long, without lateral rows of fine setules.
- Proportional lengths of urosomites and caudal ramus 41 : 22 : 15 : 22 (= 100).
- Caudal rami with setules along lateral margin, symmetrical, with 6 plumoses setae (II-VII). I absent, V longest and VII inserted anterodorsally.
- A1 17-segmented, reaching beyond posterior end of 2nd urosomite, symmetical. Segments II-VIII completely fused; segments II, IV, VII, VIII, XI, XV and XVII with aesthetasc (ae).
- A2: coxa with single seta; basis fused to elongated 1st endopodal segment forming allobasis with 8 setae on outer medial margin, and single lateral seta and trensverse row of small spinules terminally; 2nd segment with 8 outer setae and fine setules along inner margin; free terminal segment short with 6 setae. Exopod 3-segmented, satal formula: 1, 4, 3.
- Mx1: praecoxal arthrite bearing 9 strong spines; coxal endite with 3 terminal setae; coxal epipodite with 1 short and 8 long setae; basal exite with 1 terminal seta and 1 proximal seta; exopod 1-segmented fused with basis and bearing 2 long medial setae, 5 setae terminally, with fine spinules along outer marginal; endopod absent.
- Mxp: highly reduced; syncoxa with setation formula of 2 long, 1 medium and 1 short seta; basis with 1 short strong, 1 long setae and row of setules along inner margin; endopod 2-segmented, with 4 inner spines and terminal spiniform element.
Plate 4 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.78, Fig.3].
Female: A, Md; B, Mx2; C, P1; D, P2; E, P3; F, P4; G, P5.

- Md: gnathobase having 2 sharp cuspid teeth, 1 blunt tooth, and 3 small sharp teeth bordered by small spinules at the proximal end; basis with fine setules on medial outer marginal, single seta distally, and patch of small spinules on surface at midlength; 1st endopodal segment short with 2 short setae, 2nd segment with 11 setae; exopod 4-segmented, 1st to 4th with setal formula: 1, 1, 2, 2; 1st segment with row of small spinules.
- Mx2: syncoxal endite bearing 5,3, 3, 2 setae; basis with 1 long seta; endopode with 4 long, 1 medium, and 1 short setae.
- P1 to P4 biramous, each with 2-segmented endopod and 3-segmented exopod; coxa unarmed; 2nd endopodal segments of leg 1 and 4 and 3rd exopodal segment of leg 1 with row of small spinules anteriorly.
- P5 symmetrical, coxae and intercoxal sclerite completely fused; basis longer than wide, outer margin with single lateral seta, slightly longer than terminal seta of exopod; exopod with knob-like projection basally, distal half spinulose.
Plate 5 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.77, Table 1].
Female and Male: Armature formula for P1 to P4.
Spines and setae indicated by Roman and Arabic numerals, respectively.
Plate 6 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.81, Fig.5].
SEM micrographs of female.
A, Genital double-somite (lateral view); B, urosomite (ventral view); C, Genital double-somite ( ventral view).

Nota: Paired genital slits are located at midlength and moderately separated (fig. B, C. A row of setules is located along the anterior margin of each genital slit (fig.C)
Plate 7 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.80, Fig.4].
Male: A-B, habitus (dorsal and lateral, respectively); C, left A1; D, right A1. (Roman numerals denote ancestral segment numbers).
E, rostrum of male; F, rostrum of female.

Nota:
- Body similar to that of female.
- Cephalosome anterior bluntly triangular in dorsal view.
- Rostrum with paired filaments, slightly curved (versus straight in female).
- Posterior prosome symmetrical with pair of short acute processes dorsolaterally and longer ventrolateral acute processes, with pair of small prominences between 2 dorsolateral processes. Postrior margin of prosome naked.
- Urosome of 5 somites, symmetrical in dorsal view.
- Genital somite (1st urosomite) as long as wide, bearing 2 dorsolateral rows of small spinules.
- 2nd urosomite with 2 pairs of strong posterior dorsolateral processes, outer shorter than inner, and furnished with 3 rows of minute spinules ventrolaterally.
- 3rd urosomite with pair of strong acute processes dorsally; .
- 4th urosomite 4.5 times shortert han wide and furnished with pair of small medium-sized acute processes dorsally.
- Anal somite with setules along outer margins.
- Caudal rami symmetrical, approximately 1.5 times as long as wide, having lateral setules along inner margin , 6 plumose (II-VII) setae as in female.
- Left A1 incompletely 21-segmented; segments 2, 3 and 21 incompletely fused. Right A1 geniculate, incompletely 17-segmented, not reaching beyond posteriorv end of 5th pedigerous somite; segments 2 and 3 incompletely fused; segments 2, 3, 4, 7, 9, 15, 17 each with aesthetasc (ae); segments 4, 7 and 12 each with spiniform element.
Plate 8 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.78, Fig. 3, H].
Male: H, P5.

Nota: P5 uniramous; coxae unarmed and completely fused with intercoxal sclerite; each side of basis with outer plumose seta subterminally, left basis about 2.5 times as lo,g as wide, with concave inner margin. Right exopod 3-segmented, 1st segment about 3 times as long as wide with single seta subterminally, 2nd segment with small subterminal spine at mid-length of inner irregularly triangular knobs, 3rd segment curved inward with small terminal spine and small inner spine midway. left exopod 2-segmented, 1st segment about 2.5 times as long as wide, 2nd segment with long inner seta and small terminal spine.
Plate 9 Issued from : S. Lee, H.Y. Soh & W. Lee in ZooKeys, 2019, 893. [p.84, Table 3]. Acartia (Odontacartia) edentata: Morphological characters.
Compare with other Odontacartia species.

Nota:
1 - Absence of spine on 1st to 2 nd segments of female A1 .....2.
2 - Dorsal surface of female genital double-somite devoid of processes (spines and spinules) ....... 3.
3 - Female caudal rami three times longer than wide; medial process and 2nd exopodite segment of male left P5 twice longer than 2nd exopodite segment.

Distribution

NZ: 1

Distribution map of Acartia (Odontacartia) edentata by geographical zones


Additional Maps & Charts

Map 2 Issued from : K. Srinui, S. Ohtsuka, E.B. Metillo & M. Nishibori in ZooKeys, 2019, 814. [p.73, Fig. I].

Localisations

Philippines (Carigara Bay, off Leyte Island)

11°30'70'' N, 124°69'01'' E.

Quotations

N: 1

Dimensions (mm)

(1224)F: 1,19-1,23; M: 1,08-1,15; {F: 1,19-1,23; M: 1,08-1,15}

Remarks

The species belongs to sub-group centrura from Acartia (Odontacartia).
Among the centrura species, the female of A/ (O.) edentata is unique in lacking paired posterior dorsolateral processes on the genital double-somite unlike those of the closely related A. (O.) pacifica from Japan and Korea, and O. ohtsukai according to Ueda & Bucklin (2006).
For Srinui & al. (2019, p.84) in the tropical zone, A. (O.) edentata collected in the Philippines during the rainy season (August), when water temperature and salinity were 30.2 °C and 33.2 per 1000, respectively, in contrast A. (Acanthacartia) tsuensis represents the dominant species in brackish pond water from Panay Island §central Philippines) during the dry season (November-April), with salinity ranging from 14.0 to 40.0. The authors conclude that three species of Acartia (A. (O.) ohtsukai, A/ (O.) pacifica, A. (O.) edentata, and probably other Acartia species appear to occupy water bodies differing in temperature and salinity of the tropical and subtropical zone of the Pacific and Indian oceans.
Last update : 09/03/2020

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