Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Aetideidae ( Family )
            Aetideus ( Genus )
Aetideus truncatus  Bradford, 1971   (F,M)
Bradford, 1971 (p.26, figs.F,M); Markhaseva, 1996 (p.24, figs.F,M, Rem.)
Species Aetideus truncatus - Plate 1 of morphological figuresissued from : J.M. Bradford in N.Z. Jl Mar. Freshw. Res., 1971, 5 (1). [p.26, Fig.10]. From NE pacific: 22°59'N, 107°13' W.
Female: a, b, rostrum (from two different specimens); c, genital segment and posterior thoracic point (lateral left side); d, habitus (dorsal); e, idem (lateral left side).
Nota: Rostrum : Width: Depth ratio = 1.46-1.84 (see fig.5c to A. australis). Head vaulted above mandible and Mx1 (in lateral view). Seminal receptacle with a thick neck joining dorsal and ventral sacs. Mouth parts and swimming legs are identical with those of A. armatus.

Male: f, P5; g, 3rd exopod segment of P3; h, habitus (dorsal).
Nota: Rostrum absent. Fusion line between thoracic segment 4 and 5 visible dorsally. The terminal exopod spines on P3 with 21 teeth (these teeth appear to be more widely spaced than in A. armatus.

Species Aetideus truncatus - Plate 2 of morphological figuresissued from : J.M. Bradford in N.Z. Jl Mar. Freshw. Res., 1971, 5 (1). [p.18, Fig.4, b]. [modified C.R]
Rostrum width : depth plotted against rostrum depth (c) for Aetideus truncatus.
Compare with A. autralis, A. pseudarmatus, A. divergens and A. armatus.

Species Aetideus truncatus - Plate 3 of morphological figuresissued from : E.L. Markhaseva in Trudy Zool. Inst. RAN, St. Petersburg, 1996, 268. [p.25, Fig.12].
Female (from 12°N, 133°W).

Species Aetideus truncatus - Plate 4 of morphological figuresAetideus truncatus female:
1 - Posterior corners of last thoracic segment prolonged into points.
2 - Posterior corners not prolonged into wing-like lobes. Points not reaching the middle of urosomal segment 2. Anterior part of vephalon without crest.
3 - Basipodite of right P1 without external tooth-like distally projection distally. Coxopodite of P4 usually with spinules near the base of internal seta.
4 - Points of posterior corners not reaching posterior border of genital segment.
5 - Rostrum small, rami short, widely spaced. A1 shorter than body.

Species Aetideus truncatus - Plate 5 of morphological figuresAetideus truncatus male:
1 - Last thoracic segment with points.
2 - Posterior corners of last thoracic segment not exceeding posterior border of urosomal segment 1 (in dorsal view).
3 - 2nd segment of P5 2.3-3.1 times as long as wide.
4 - Exopodal segment 3 of P3 with terminal spine longer than the segment itself.

Compl. Ref.:
Suarez-Morales & Gasca, 1998 a (p.107); in CalCOFI regional list (MDO, Nov. 2013; M. Ohman, pers. comm.)
NZ: 1

Distribution map of Aetideus truncatus by geographical zones
Species Aetideus truncatus - Distribution map 2issued from : J.M. Bradford in N.Z. Jl Mar. Freshw. Res., 1971, 5 (1). [p.35, Fig.14].

North Pacific Ocean showing distribution of four Aetideus species.
NE Pacif. (tropical), CalCOFI region, Baja California
N: 2
(204) F: 1,8-1,6; M: 1,45; {F: 1,60-1,80; M: 1,45}
Rem.: epi to mesopelagic.
According to Bradford (1971, p.27) the females are distinguished from all others species, the males are very difficult to distinguish from A. armatus.
Last update : 27/12/2014
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Razouls C., Desreumaux N., Kouwenberg J. and de Bovée F., 2005-2021. - Biodiversity of Marine Planktonic Copepods (morphology, geographical distribution and biological data). Sorbonne University, CNRS. Available at http://copepodes.obs-banyuls.fr/en [Accessed February 28, 2021]

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