Calanoida ( Order )
    Diaptomoidea ( Superfamily )
Tortanidae Sars, 1902 ( Diaptomoidea )
Ref.: Sars, 1902 (1903) (p.73); Gurney, 1931 a (p.215); Brodsky, 1950 (1967) (p.83, 428); Bowman & Abele, 1982 (p.9); Razouls, 1982 (p.622); Brodsky & al., 1983 (p.141, 145); Sazhina, 1985 (p.120); Mauchline, 1988 (p.717, 740: pores cuticulaires); Huys & Boxshall, 1991 (p.419); Zheng Zhong & al., 1984 (1989) (p.259, clé spp.); Chihara & Omori, 1997 (p.924); Barthélémy, 1999 a (p.24); Bradford-Grieve & al., 1999 (p.886, 901, 904, 963); Ohtsuka & Huys, 2001 (p.461); Boxshall & Halsey, 2004 (p.12; 49; 212, Def., Subgenera. key; p.214: Rem: this family placed by Andronov (1974) among Centropagoidea is transferred to the super-family Diaptomoidea. Blanco-Bercial & al., 2011 (p.103, Table 1, Fig.2, 3, 4, molecular biology, phylogeny); Laakmann & al., 2019 (p.330, fig. 2, 3, phylogenetic relationships)
Bradford-Grieve J.M., (2002 onwards). Key to calanoid copepod families. Version 1 : 2 oct 2002.
Rem.: 1 G.: Tortanus.
Family Tortanidae - Plate 1Issued from : G.A. Boxshall & S.H. Halsey in The Ray Society, 2004, No 166, Part. I. [p.214].
Key of subgenera.

Family Tortanidae - Plate 2Issued from : G.A. Boxshall & S.H. Halsey in An Introduction to Copepod Diversity.The Ray Society, 2004, No 166, Part. I. [p.212].
Armature formula of swimming legs P1 to P4.
(1) Tortanus Giesbrecht,1898; emend. Ohtsuka & Reid, 1998
Syn.: Corynura Brady, 1883 (p.70); Giesbrecht, 1892 (p.76, 525); Wheeler, 1901 (p.184)
Ref.: Giesbrecht & Schmeil, 1898 (p.157); van Breemen, 1908 a (p.162); A. Scott, 1909 (p.189); Esterly, 1924 (p.108); Steuer, 1926 (p.49, Rem.: 3 groups); Sewell, 1932 (p.398, Rem.: 2 Subgenera: Atortus and Tortanus); Wilson, 1932 a (p.166); Davis, 1949 (p.66); Mori, 1937 (1964) (p.105); Brodsky, 1950 (1967) (p.429); Tanaka, 1965 (p.395); Gonzalez & Bowman, 1965 (p.259); Bowman , 1971 b (p.521); Razouls, 1982 (p.622, Rem., concerning the Subgenus Atortus); Gardner & Szabo, 1982 (p.423); Othman, 1987 (p.71); Mauchline, 1988 (p.717: cuticular pores); Ohtsuka, Fukuura & Go, 1987 (p.58); Ohtsuka & Kimoto, 1989 (p.392, 405); Ferrari, 1992 (p.392, tab.3); Ohtsuka, 1992 a (p.255, 264, Rem : 4 Subgenera.); Razouls, 1993 (p.308); Chihara & Omori, 1997 (p.924); Mauchline, 1998 (p.97: F, M); Ohtsuka & Reid, 1998 (p.775, Rem.: 5 S.G., Subgenera Key); Bradford-Grieve, 1999 b (p.228, Def., Rem.); Boxshall & Halsey, 2004 (p.214, Subgenera Key); Mulyadi, 2004 (p.164, Def.)
Rem.: Type: Corynura gracilis Brady, 1883. 5 S.G.: Acutanus , Atortus, Boreotortanus, Eutortanus , Tortanus . Total: 47 spp. + 1 undet.

Diagnosis from Bradford-Grieve (1999 b, p.228):
- 1 median eye.
- No rostrum; a semicircular plate, thickly covered with short bristles, lies anterior to the labrum.
- Head and pediger segment 1 separate, pediger segments 4 and 5 fused or separate.
- Posterior corners of pediger segment 5 with rounded or pointed extremities which are small or absent in the male.
- Urosomal segments 2- or 3-segmented in female
- Genital segment female without seminal receptacles.
- Urosome 5-segmented in male, often asymmetrical, both because of asymmetry in individual segments and as a result of curvature along the longitudinal axis; urosome asymmetry less frequent in males.
- Female genital segment often asymmetrical, bearing a common genital aperture located medially on ventral surface, copulatory pore contained within median gemital aperture.
- Caudal rami sometimes asymmetrical, one larger than the other, often fused to the anal segmebt, with 6 setae.
- A1 12- to 15-segmented, prehensile on the right side in the male, its middle part widened and sometimes equipped with a denticulate plate.
- A2 coxa and basis separate, endopod and basis often fused; with exopod indistinctly 3-segmented, typically with an unarmed 1st segment, a long middle segment with up to 3 setae, and a short segment with 2 setae; endopod 2-segmented with 6 terminal setae.
- Md with an elongate palp; unarmed basis; endopod 2-segmented with 0 and 6 setae; exopod indistinctly 1- 4-segmented with 5 setae in total.
- Mx1 with much reduced number of lobes (inner lobe 1 one other the only ones present); inner lobe 1 with up to 13 spines and setae, the distal segment elongate bearing 3 powerful claw-like setae around the apex, and up to 7 short setae subapically.
- Mx2 with lobes 1-3 reduced; the remaining lobes bear claw-like setae.
- Mxp reduced with 2 long spines on the 1st segment; the distal part pof the limb bearing 3 or 4 setae on the inner margin and 1 on the outer margin of the distal segment.
- Swimming legs with3-segmented exopods; endopod of P1 2 or 3-segmented; P2-P4 with 2- segmented endopodss.
- Female P5 simple, uniramous, 2-3-segmented; coxa and coupler fused; basis with an outer seta; free exopodal segment typically with 1 outer margin spine and 3 spinous processes arranged around the margins; exopod segment sometimes in the form of a curved tapering process.
- Male P5 asymmetrical, uniramous; right leg 3-segmentd, 1st segment unarmed, 2nd segment often expanded into a medial or distal lamellate process armed with up to 3 setae, 3rd segment forming a subchela typically curved and armed with 3 or 4 small setae; left leg 4-segmented, 1st segment unarmed, 2nd and 3rd segments elongate, each with an inner and outer seta, 4th segment curved, typically armed with 2 setae on the inner margin, 1 apical seta and 2 on the outer margin; the inner seta on the 3rd segment often carried on a slender process.

Diagnosis from Mulyadi (2004, p.164):
- Cephalon without lateral hook.
- Rostrum absent, horse shoe-shaped plate fringe with hairs anterior to upper lip.
- Eye large, without lenses.
- Cephalon and pediger somite 1 separated, pediger somites 4 and 5 fused or separated.
- Corners of last thoracic somite pointed and sometimes asymmetrical in female, rounded in male.
- Urosome 2 or 3 somites and usually asymmetrical in female; 5 somites in male.
- Caudal rami usually very asymmetrical in female, less so in male.
- A1 17-segmented; male right A1 prehensile, thickened at middle.
- Endopod of A2 little longer than exopod.
- Basis of Md long; outermost tooth of gnathobase large and well separated from other teeth.
- Mx1 reduced to basal segment bearing short broad proximal lobe and long narrow distal lobe, the latter with 2 long and 1 shorter apical setae.
- Mx2 with much reduced proximal lobe.
- Mxp with well-developed basal segment armed with strong setae; endopod much reduced.
- P1-P4 with 3 exopodal segment, 2 or 3 endopodal segments in P1, 2 endopodal segments in P2-P4.
- P5 uniramous in both sexes, 2-3-segmented and sometimes asymmetrical in female; right P5 male forming a chela.

Key to subgenera from Ohtsuka & Reid (1998, p.775) :
1 – Right caudal ramus of female bearing large acute outer process ; right caudal seta II of male much thicker and longer than left ; 2 nd endopod segment of leg P4 bearing 7 setae …….. Tortanus (Boreotortanus) Ohtsuka & Reid, 1998.
1’ – Caudal rami of both sexes not as above ; 2 nd endopod segment of leg P4 with 6 setae ……… 2.
2 – Mxp syncoxa beraing 5 setae ……. 3.
2’ - Mxp syncoxa bearing only 2 setae …… 4.
3 – In both sexes, dorsal terminal triangular process present on both caudal rami ; prosomal corners of female not produced ; caudal rami of male exyremely slender, as long as or longer than urosomites compined, 2 nd endopod segments of legs P2 and P3 each bearing 7 setae …….. T. (Tortanus) Giesbrecht, 1898.
3’ – In both sexes, dorsal terminal triangular process absent on both caudal rami ; prosomal corners of female produced posteriorly into winglike process ; caudal rami of male shorter than urosomites compbined ; 2 nd endopod segments of legs P2 and P3 each bearing 8 setae ……T. (Eutortanus) Smirnov, 1935.
4 – In both sexes, pedigers 4 and 5 separate ; female P5 with with 1-segmented exopodbearing either 4 spines or 3 spines plus 1 process ; in right P5 of male, exopod arising proximally from basis …….. T. (acutanus) Ohtsuka, 1992.
4’ – In both sexes, pedigers 4 and 5 fused ; female exopod of P5 either reduced or 1-segmented, tapering distally with spines/processes ; in right P5 of male, exopod arising distally from basis …….. T. (Atortus) Ohtsuka, 1992.
Remarks on dimensions and sex ratio:
The mean female size is 2.123 mm (n = 37; SD = 0.4937), and the mean male size is 1.789 mm (n = 37; SD = 0.4570). The size ratio (Male: Female) is 0.84 (n = 36; SD = 0.0848). The sex-ratio (Female: Male) is 1,03.
Acutanus Ohtsuka, 1992
Ref.: Ohtsuka, 1992 a (p.264, Def.); Ohtsuka & Reid, 1998 (p.775, 782, spp. Key); Boxshall & Halsey, 2004 (p.214)
Rem.: type: Tortanus angularis Ohtsuka, 1992.Total: 4 spp.

Diagnosis from Ohtsuka (1992, p.256):- Prosome of female about twice as long as urosome.
- Pedigers 4 and 5 separate.
- Pediger 5 symmetrical.
Urosome of female-segmented.
Female genital somite nearly symmetrical; genital opeculum crescent-shaped.
Anal somite with acute dorsal process medially, incompletely fused with caudal rami.
- 2nd-to innermost caudal setae of both rami normally thickened and not so swollen as in subgenus Atortus.
- Urosome of male 5-segmented; right posterior margin of 2nd somite producede into spine-like process posteriorly.
- Anal somite male separated from caudal rami and having acute dorsal process (as in female).
- Male right A1 with segments 19-21 fused, not so produced terminally as in Atortus.
- Mx1 with 11 setae on arthrite.
- Coxa of Mxp bearing 2 large spinulose setae.
- P1-P4 with 2-segmented endopod and 3-segmented exopod.
- Terminal exopodal segment of P1 with 1 outer spine.
- Terminal exopodal segment of P2 with 2 outer lateral spines.
- Terminal endopodal segments of P1-P4 each having 6 setae.
- Female P5 uniramous, 3-segmented; terminal segment bearing 1 outer lateral and 3 terminal spines, innermost of which may be fused to terminal segment.
- Proximal exopodal segment of right P5 male swollen; distal exopodal segment originating from near inner base of proximal exopodal segment; inner lateral margin of proximal segment facing outer lateral margin of distal exopodal segment to form chela.

Diagnosis emended from Ohtsuka & Reid (1998, p.782):.
- P2 bearing 0 or 1 outer spine on 2nd exopodal segment; 3rd exopodal segment bearing 2 or 3 spines.
- P3 with or without outer spine on 2nd exopodal segment; 3rd exopodal segment bearing 2 or 3 outer spines;
- P4 with 2 or 3 outer spines on 3rd exopodal segment.
- Right P5 male with contorted exopod arising from inner proximal margin of basis.

The subgeneric name ''Acutanus'' refers to the acute dorsal process on the anal somites in both sexes.

The mean female size is 1.116 mm (n = 4; SD = 0.1669), and the mean male size is 0.873 (n = 4; Sd = 0.1046). The size ratio (Male: Female) is 0.79. The sex ratio (female: male) is 1.
Atortus Ohtsuka, 1992
Ref.: Sewell, 1932 (p.400); Bowman, 1971 a (p.521, 527: biogeography); Ohtsuka & Kimoto, 1989 (p.392, 404: biogeography); Ohtsuka, 1992 (p.265, Def.); Chihara & Omori, 1997 (p.925); Ohtsuka & Reid, 1998 (p.775, 786, spp. Key); Ohtsuka & Conway, 2003 (p.355, 358: Rem.); Boxshall & Halsey, 2004 (p.214); Nishida & Cho, 2005 (p.224, Rem.: p.229, geographic distribution, chart); Nishida & al., 2015 (p.224, Rem.); Mulyadi & al. (2017, p.97: Rem.: description of the co-occurence of 7 species of Tortanus (Atortus) in North Sulawest, Indonesia); Ohtsuka & Nishida, 2017 (p.575, Rem.); Brylinski & Courcot (2019, Rem.: p.365, coupling device); Francis & Bijoy Nandan, 2019 (p.433: Species key of the subgenus Atortus from the Indian Ocean)
Rem.: type: Tortanus murrayi A. Scott, 1909. Total : 31 spp.
Nishida & Cho (2005, p.230) point to the environmental conditions for the species of the subgenus (high-temperature, more or less oligotrophic high-salinity waters).
Ohtsuka & Kimoto (1989) distinguish 2 species groups within the ''tropicus species complex'': the longipes Group (T. giexbrechti, T. longipes and the rubidus Group (T. bowmani, T. digitalis, T. rubidus) plus T. taiwanicus (Ohtsuka & al., 2000). After characters T. vietnamicus is more or less a mixture of those of the two groups.

Diagnosis from Ohtsuka (1992, p.265):
- Prosome female about 3 times as long as urosome.
- Pediger somites 4 and 5 fused.
- Urosome female 2- or 3-segmented.
- Caudal rami not as elongate as in subgenus Tortanus.
- Mx1 arthrite with 13 setae.
- Coxa of Mxp with 2 long setae.
- Endopod of P1 2-segmented.
- Terminal endopodal segments of P3 and P4 with 6 setae.
- Terminal exopodal segments of P1 and P2 bearing 1 and 3 outer spines, respectively.
- Terminal endopodal segment of P2 with 6 setae.

For Nishida & al. (2015, p. 224) the tropicus species-group is defined by the combination of the characters: 1- 2nd urosomite of the male with a process on the right side; 2- the anterior end of the serrate margin of the ancestral segment XX of right A1 male produced proximally over the segment XIX; 3- the distal segment of P5 female either slender and asymmetrical or subquadrate. The following 12 species are the current members of this group: T. brevipes Scott, 1909; T. tropicus Sewell, 1932; T. longipes Brodsky, 1950; T. tubidus Tanaka, 1965; T. giesbrechti Jones & Park, 1968; T. bowmani Othman, 1987; T. ryukyuensis Ohtsuka & Kimoto, 1989; T. digitalis, T. taiwanicus Chen & Hwang, 1999; T. vietnamicus Nishida & Cho, 2005; T. andamanensis, T. sigmoides Nishida, Anandavelu & Padmavati, 2015.

The mean female size is 2.374 mm (n = 22; SD = 0.8416), and the mean male size is 1.998 (n = 22; SD = 0.2584); The size ratio (male: female) is 0.85 (n = 21; SD = 0.0743). The sex ratio is probably 1.

After Brylinski & Courcot (2019, p.9) some species of the subgenus show complex spermatophore having highly complex coupling device on the flat spermatophore that almost entirely covers the female urosome (Barthélémy & al., 2003) [Cf in the genus Stephos concerning the ''sheath structure''].

Ohtsuka & Nishida (2017, p.575) point to a comprehensive speciation pattern was proposed for the Indo-Pacific coastal L. pectinata species complex, based on vicariant events in accord with eustatic changes in sea level during the Pleistocene (< - 2.6 million years)) (Flemi,ger, 1986), such a vicariant mechanism is applicable to Tortanus (Atortus) species complexes.
Boreotortanus Ohtsuka & Reid, 1998
Ref.: Ohtsuka & Reid, 1998 (p.775, 776, Def.); Boxshall & Halsey, 2004 (p.214)

Type: Corynura discaudata Thompson & Scott, 1897.

Diagnosis after S. Ohtsuka & J.W Reid (1998, p.776) :
- Prosome female approximately 1.8 times as long as urosome.
- Pedigers 4 and 5 separate in female and incompletely separate in male.
Posterolateral corners of female pediger 5 produced backward into triangular process.
- Urosome female asymmetrical, 3-segmented ; 2nd urosomal and anal somites with patch of minute spinules on right side.
- 2 nd urosomal somite of male posterolaterally produced on right side.
- Caudal rami and anal somite fused in female, separate in male ; right caudal ramus of both sexes more expanded and longer than left, right seta II modified as large acute process in female, thicker and longer than left one in male.
- Ancestral segment I of A1 separate from segment II in both sexes.
- Mx1 praecoxal arthrite with 11 elements.
- Mxp syncoxa bearing 5 setae .
- P1 with 3-segmented endopod.
- 3rd exopod segments of P1 and P2 bearing 2 and 3 outer spines, respectively.
- 2 nd endopod segments of P2-P4 having 8, 8, and 7 setae, respectively.
- Both P5 of female 3-segmented, left slightly longer than right ; exopod 1-segmented, tapering distally, with 3 minute outer spinules, inner margin smooth .
- Basis of right P5 male swollen inwardly, with 2 triangular processes along inner margin, each having setule at tip ; exopod bearing large inner proximal process. Left P5 with basis and 1st exopod segment relatively short, 1st exopod segment with long stout outer spine subterminally, 2nd segment with short outer spine at midlength.
Eutortanus Smirnov, 1935
Ref.: Smirnov, 1935 (p.41); Ohtsuka, 1992 (p.263); Ohtsuka & al., 1992 (p.114, Def.,121: zoogeography, chart); Ohtsuka & al., 1995 (p.155: biogeography); Chihara & Omori, 1997 (p.924); Ohtsuka & Reid, 1998 (p.775, 787, emend., spp. Key); Itoh & al., 2001 (p.66, geographical distribution: fig.6); Boxshall & Halsey, 2004 (p.214); Ohtsuka & Nishida, 2017 (p.576)
Rem.: type: Tortanus derjugini Smirnov, 1935. Total: 7 spp.

Diagnosis from Ohtsuka & al. (1992, p.114):
- Female prosome approximately twice as long as urosome.
- 4th and 5th pediger somites of both sexes completely or incompletely fused.
- 5th pediger somite of female produced posterolaterally into triangular process whereas that of male produced posteriorly into blunt process;
- Urosome female relatively short, 3- or 4- segmented.
Anal somite of female incompletely fused with caudal rami.
- 1st abdominal somite of male without process on the right side.
- Right caudal rami of both sexes slightly longer than left; caudal anterolateral seta modelately long.
- Mx1 arthrite with 12 setae and 1 setule.
- Coxa of Mxp with 5 setae.
- Endopod of P1 3-segmented.
- Distal exopodal segment of P1 and P2 with 2 and 3 outer spines, respectively.
- Distal endopodal segments of P2-P4 having 8, 8 and 6 setae, respectively.
- Both P5 female 3-segmented; left leg slightly longer than right; distal segment tapering distally, its inner margin fringed with hairs.
- Penultimate segment of right P5 male considerably expanded inward, accompanied with 1 inner medial process and with or without inner subterminal triangular process; distal segment of right P5 moderately or extremely elongate; basis and exopodal segments of left P5 relatively short.

Diagnosis from Ohtsuka & Reid (1998, p.787) emended:P1 with 2- or 3-segmented endopod.

The mean female size is 2.088 mm (n = 7; SD = 0.4572), and the mean male size is 1.845 (n = 7; SD = 0.3310). The size ratio (Male: Female) is 0.89. The sex ratio (Female: Male) is 1.

Ohtsuka & Nishida (2017, p.576) note that the ancient East China Sea, during the Pleistocene (> - 2.5 million years) was considered as an enormous gulf of low-salinity water in glacial periods, and as a historic center of speciation for present-day brackish taxa (Nishimura, 1981). All members of the subgenus Eutortanus originated from this gulf and were adapted to brackish water. The only exeption T. (E.) terminalis is adapted to high -salinity water, and seems to have expanded its distribution eastward along the coast of Honshu Island, possibly because it had originated in high salinity near the mouth of the Gulf (Ohtsuka & Reid, 1998).
Tortanus Giesbrecht & Schmeil, 1898
Syn.: 'Groupe 2: gracilis-forcipatus-barbatus' Steuer,1926 (p.49)
Ref.: Bowman, 1971 a (p.521); Ohtsuka,1992 (p.264, Def.); Chihara & Omori, 1997 (p.924); Ohtsuka & Reid, 1998 (p.775, 781, spp. Key); Boxshall & Halsey, 2004 (p.214); Mulyadi, 2004 (p.164)
Rem.: type: Corynura gracilis Brady, 1883. Total : 3 spp.

Diagnosis from Ohtsuka (1992, p.264), after Steuer (1926) and Sewell (1932):
-Female prosome approximately 1.5 times as long as urosome.
Pediger somites 4 and 5 separate.
Urosome elongate, 3-segmented in female.
- Both right and left caudal rami female fused with anal somite.
- Endopod of P1 2-segmented.
- Terminal endopodal segments Of P3 and P4 having 7 and 6 setae, respectively (according observation of T. forcipatus and T. gracilis, Sewell's (1932) statement that the terminal endopodal segments of both legs 3 and 4 have 7 setae was not correct).
- Both sexes of three species (T. barbatus, T. forcipatus, T. gracilis) have a terminal dorsal process on each caudal ramus; moreover these three species share the following characters: teminal exopodal segments of P1 and P2 with 2 and 3 lateral spines, respectively; terminal endopodal segment of P2 with 7 setae; Mx1 arthrite with 12 setae; coxa of Mxp with 5 setae.

The mean female size is 1.660 mm (n = 3; SD = 0.1359), and the mean male size is 1.232 mm (n = 3; SD = 0.2975). The size ratio (male: female) is 0.74. The sex ratio is 1.

 Any use of this site for a publication will be mentioned with the following reference :

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 [Accessed July 25, 2024]

© copyright 2005-2024 Sorbonne University, CNRS

CNRS   Observatoire Océanologique de Banyuls sur Mer - Laboratoire Arago
Sorbonne Université


Version française
English version



On the WEB of CNRS


Marine Planktonic Copepods

Marine Planktonic Copepods


Imprimer Contact Accueil Plan du site Accès restreint Retour Une du Labo Imprimer Contact Plan du site Crédits Téléchargez les Plug-Ins