Species Card of Copepod
Calanoida ( Order )
    Arietelloidea ( Superfamily )
        Heterorhabdidae ( Family )
            Neorhabdus ( Genus )
Neorhabdus subcapitaneus  Park, 2000   (F)
Syn.: ? Hemirhabdus truncatus: Sewell, 1947 (p.181)
Park, 2000 (p.68, Descr.F, figs.F)
Species Neorhabdus subcapitaneus - Plate 1 of morphological figuresissued from : T. Park in Bull. Scripps Inst. Oceanogr. Univ. California, San Diego, 2000, 31. [p.194, Fig.42].
Female: a, habitus (left side); b, c, urosome (left, dorsal, respectively); d, genital somite (ventral); e, left A2 (posterior); f, left Mx1 (posterior); g, left Mx2 (posterior); h, right Mxp (anterior).

Nota: Prosome about 3/4 length of body and about 3 times length of urosome.
Cephalosome about 2/5 length of prosome.
Rostrum small bearing 2 slender filaments.
Posterior margin of prosome rounded. Dorsally, posterolateral corners (Fig.42-c) produced into obtuse angles covering about 1/5 length of genital somite.
Urosome about 1/4 length of body.
Genital operculum (Fig.42-d) typically with a width-length ratio of 100:51 and about 4/9 as wide as somite itself.
Genital field with about 7 pores on each side.
2nd urosomal somite about 5/9 length of genital somite and about 1.2 times length of 3rd urosomal somite
Anal segment about 1.1 times length of 3rd urosomal somite.
Combined lengths of anal segment and left caudal ramus about 1.2 times length of genital somite.
Dorsally, right caudal ramus separate from anal segment, but left caudal ramus only partially separate from it. Left caudal ramus only slightly longer than right, its dorsal appendicular seta a little longer than that of right.
A1 reaching about posterior end of 2nd urosomal somite. Four lobes of 1st segment with 1+2+2+2 setae and 0+1+4+6 aesthetes; 2nd to 19th segments each with 2 setae. Number of aesthetes found on each of first 12 segments: 2 on 2nd segment, 5 on 3rd, 3 on 4th, 5 on each of 5th and 6th, 4 on 7th, 6 on 8th, 5 pn 9th, 3 on 10th, 4 on 11th, 3 on 12th (aesthetes on distal part of A1 not well preserved).

Species Neorhabdus subcapitaneus - Plate 2 of morphological figuresNeorhabdus subcapiteanus female and male:
1 - In 3rd lobe of Mx2, anterior spine about as long as 1st terminal spine (Fig.42-g); Mx1 with 2nd inner lobe bearing 1 seta (Fig.42-f).
2 - Last exopodal segment of A2 with normally developed inner marginal seta (Fig.42-e); 2nd-7th segments of A1 each with less than 10 aesthetes.
3 - A1 extending beyond posterior end of prosome by last 3 segments; Mxp coxa with 1+2 setae (Fig.42-h); Mx1 exopod with 4 setae (Fig.42-f).

NZ: 2 + 1 doubtful

Distribution map of Neorhabdus subcapitaneus by geographical zones
off SE Cape Cod, ? Arabian Sea, Pacif. (tropical E & SE)

Type locality: 17°46'S, 110°19'W
N: 1
(824) F: 10,83-9,5; {F: 9,50-10,83}
Rem.: For Park (2000, p.69) the species is very close to N. capiteanus but can be distinguished from it: 1 - It is considerably smaller; 2 - A1 reaching about posterior end of 2nd urosomal somite, instead of posterior end of anal segment as in N. capiteanus, with no more than 6 aesthetes per segment; 3 - inner marginal seta on last exopodal segment of A2 well developed, while this seta is vestigial in N. capteanus; 4- endopodal setae of Mx2 relatively short; coxa of Mxp with 2 distal setae of strongly different size.
After the same author, Sewell's (1947) record of N. truncatus (Scott 1909) from the Arabian Sea was probably based on this species. As noted, Sewell's specimen (9.66 mm long) is closer in body size to this species than to Scott's original specimen (7 mm long).
Last update : 24/01/2015
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Razouls C., Desreumaux N., Kouwenberg J. and de Bovée F., 2005-2023. - Biodiversity of Marine Planktonic Copepods (morphology, geographical distribution and biological data). Sorbonne University, CNRS. Available at http://copepodes.obs-banyuls.fr/en [Accessed November 28, 2023]

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