Centropagidae Family - Marine Planktonic Copepods

Calanoida ( Order )	details
Diaptomoidea ( Superfamily )	details

Abbreviations or symbols

Centropagidae Giesbrecht, 1892 ( Diaptomoidea )

Ref.:

Giesbrecht, 1892 (p.58); Giesbrecht & Schmeil, 1898 (p.52); Sars, 1902 (1903) (p.73); Esterly, 1905 (p.170); van Breemen, 1908 a (p.91); Gurney, 1931 a (p.85); Rose, 1933 a (p.183); Mori, 1937 (1964) (part., p.8, 55, Genera Key); Brodsky, 1950 (1967) (p.314); Gonzalez & Bowman, 1965 (p.247); Bayly & Arnott, 1969 (Rev., p.190, 194, Genera Key); Lee, 1972 (p.1, spematophore, coupling device); Andronov, 1974 a (p.1005); Kiefer, 1978 (p.55); Bowman & Abele, 1982 (p.9); Razouls, 1982 (p.430); Dussart & Defaye, 1983 (p.11); Brodsky & al., 1983 (p.141, 146); Sazhina, 1985 (p.115, N); Dussart, 1986 (p.63); Mauchline, 1988 (p.712: pores cuticulaires); Zheng Zhong & al., 1984 (1989) (p.242, Rem.); Razouls, 1993 (p.307); Maly, 1996 (p.727); Madhupratap & al., 1996 (p.863, Table 5: %/copepods); Chihara & Murano, 1997 (p.765); Barthélémy, 1999 a (p.23); Bradford-Grieve & al., 1999 (p.884, 901, 904, 950); Bradford-Grieve,1999 b (p.131, Def.); Ohtsuka & Huys, 2001 (p.461); Boxshall & Halsey, 2004 (p.12, 13; 49; 86: Def.; p.88: Genera Key); Vives & Shmeleva, 2007 (p.464, Genera Key); 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. http://www.crustacea.net/crustace/calanoida/index.htm

Rem.:

Type-genus: Centropages Krøyer, 1849. Total: 14 G.
This family comprises two marine genera: Centropages, Isias, the other are brackish- and freshwater genera (cf. in Dussart & Defaye, 1983, p.11 & foll.; Adamowicz & al., 2007, p.279 & foll.): Boeckella De Guerne & Richard,1889; Rev. Bayly,1964; Calamoecia Brady,1906; Gippslandia Bayly & Arnott, 1969 (cf. in Bradford-Grieve, 1999 b (p.140, Def., Rem.); Gladioferens Henry,1919 (cf. in Dakin & Colefax, 1940, p.89; Bradford-Grieve,1999 b (p.141, Def., Rem.); Hemiboeckella Sars,1912; Karukinka Menu-Marque,2002; Limnocalanus Sars,1863; [Metaboeckella Ekman,1905]; Neoboeckella Bayly,1992; Osphranticum Forbes,1882; Parabroteas Mrazek,1901; [Pseudoboeckella Mrazek,1901 = Boeckella]; Parathalassius Dussart,1986 (cf. in Bradford-Grieve,1999 b (p.147, Def. Rem.); Sinocalanus Burckhardt, 1913; Cf. in Chihara & Murano, 1997 (p.767, Pl.87); [ Pseudolovenula Marukawa,1921 is a juvenile form of Megacalanus (Vervoort,1946, p.56)].

Definition after Bradford-Grieve (1999 b, p.131). Female:
- Rostrum always present, with 2 filaments.
- Cephalosome and pediger 1 separate, pedigers 4 and 5 separate.
- Last thoracic segment rounded or often with asymmetrical spiniform posterior corners.
- Urosome usually 3-segmented.
- Genital segment often with asymmetrical spine armature, without seminal receptacles.
- Urosomal segment 2 may bear processes.
- A1 24-25-segmented.
-A2 exopod and endopod almost equal in size; basipod 1 with 1 seta, basipod 2 with 2 setae; endopod 2-segmented carrying 2 and 13-15 setae respectively; exopod 7-segmented carrying 1, 3, 1, 1, 1, 1, 4 setae respectively, qlthrough further fusion of proximal segments may take place in some genera so that the exopod is 5-segmented.
- Md blade with well-developed trrth, basipod 2 with 4 setae, endopod 2-segmented with 3-4 and 6-8 setae respectively; exopod 4-segmented with 1, 1, 1, and 2-3 setae respectively.
- Mx1 variable, inner lobe 1 with 14-15 spines and setae, inner lobes 2 and 3 with 1-4, and2-4 setae respectively, basipod 2 with 2-5 setae, endopod with 2-4 + 4-13 setae, exopod with 7-11 setae, outer lobe 2 with 1 small seta, outer lobe 1 with 8-6 setae, 2 of them short.
- Mx2 well developed, lobes 1-5 with 4-5, 3, 3, 3, and 3-4 setae respectively, terminal part with 6-8 setae.
- Mxp relatively small, basipod 1 usually with 3 pronounced lobes bearing 2, 3, and 3-4 setae respectively, basipod 2 with 5 distal setae and sometimes with proximal row of inner-edge spinules, endopod 5-segmented with 2-4, 1-4, 1-3, 2-4 (1 usually on outer edge), and 3-4 setae respectively.
- P1 - P5 exopods and endopods 3-segmented; apical spine of exopod strongly serrate; sometimes endopod segments 1 and 2 fused.
- P5 biramous, natatory, basipods 1 and 2 without setae, exopod segments 1 and 2 with or without 1 outer edge spine, segment 2 with a strong inner spine-like process, exopod segment 3 with or without 2 outer edge spines, 1 terminal serrate spine and 2 or 4 inner edge setae; endopod segments 1 and 2 with 0-1 and 1 inner-edge setae respectively, endopod segment 3 with 4-6 setae.

Male:
- Urosome 4-5-segmented.
- A1 prehensile on right.
- Mouthparts and legs 1-4 usually identical to those of female.
- P5 asymmetrical, usually resembling other swimming legs, rami 2 or 3-segmented, right exopod variously transformed into a grasping organ, sometimes endopod atrophied.

Key to genera after Boxshall & Halsey (2004, p.88, both sexes are required) :
1 – Urosome of female 4-segmented ……. 2.
1’ – Urosome of female 2 or 3-segmented ……… 4.
2 – Male geniculate A1 18-segmented ……. Gladioferens ;
2’ - Male geniculate A1 22-segmented …… 3.
3 – Male with left exopod of P5 2-segmented ; female P5 endopod with 1st segment ubarmed and 3rd segment bearing 6 elements …….Osphranticum.
3’ – Male with all rami of P5 3-segmented ; female P5 endopod with inner seta on 1st segment and 4 elements on 3rd segment .………Parathalassius.
4 – Urosome of female 2-segmented ; male right P5 with stout process arising from inner margin of basis, vestigial endopod and short terminal claw ……… Neoboeckella.
4’ – Urosome of female 3-segmented ; male right P5 not as above …… 5.
5 – P1 with 1-segmented endopod ; 2-segmented endopod in P2 to P4 ………. Calamoecia.
5’ – P1 with 2 or 3-segmented endopod ; P2 to P4 with 3-segmented endopods ……. 6.
6 – Endopod of P5 1-segmented or vestigial in both sexes …….. Isias.
6’ – Endopod of P5 typically 2 or 3-segmented in both sexes ; sometimes 1-segmented or vestigial in males …….. 7.
7 – 1st and 2nd exopodal segments of P1 each with outer spine …….10.
7’ – 1st and 2nd exopodalsegments of P1 both lacking outer spine ……. 8.
8 – Endopods of P1 to P4 bearing 1 (leg 1) or 2 (legs 2 to 4) setae on outer margin of 3rd segment …….. 9.
8’ – Endopods of P1 to P4 lacking outer margin setae on 3rd segment ……….. Gippslandia.
9 – Exopod of A2 longer than endopod ; outer basal seta on female P5 lacking ; basis of male P5 lacking inner process …….. Limnocalanus ;
9’ – Exopod of A2 shorter than endopod ; outer basal seta on female P5 present ; basis of male P5 with inner process ……. Sinocalanus.
10 – 3rd exopodal segment of P2 to P4 with II, I,5 setation ; 2nd endopodal segment of P1 with inner seta ; male right P5 subchelate ……. 11.
10’ – 3rd exopodal segment of P2 to P4 with III, 1,5 setation ; 2nd endopodal segment of P1 typically with 2 inner setae ; male right P5 chelate with distal segment opposing inner process on 2nd exopodal segment …….. Centropages.
11 – Mxp robust, with endopod shorter than basis ; endopodal segments armed with strong claw-like setae ……. Parabroteas.
11’ – Mxp slender, with endopod at least as long as basis ; endopodal setae not claw-like …… 12.
12 – 2nd exopodal segment and distal element of male P5 forming long curved claw ……. Boeckella.
12’ – 2nd exopodal segment and distal spine of male P5 straight, not forming curved claw …….. Hemiboeckella.

After Brylinski & Courcot (2019, p.9) in Centropages sp. , the tubulat spermatophore is connected via a bipartite coupling device (Lee, 1972): the anterior hyaline coupler controls spermatophore fixation by closing around the genital double-somite of the female while the posterior coupler is a hyaline sheath cemented to the 2nd urosomite. In calanoid copepods producing this complex spermatophore type, the female genital double-somite is usually ornamented with spines, processes and swellings which constitute a ''lock-and-key mechanism together with the coupler (Lee, 1972. )[ Cf in the genus Stephos concerning the ''sheath structure''].

Issued from : G.A. Boxshall & S.H. Halsey in An Introduction to Copepod Diversity. The Ray Society, 2004, No 166, Part. I. [p.86].
Armature formula of swimming legs P1 to P4, and P5 female (f).
Nota:: Inner seta on basis of P1 located medial to endopod or situated on anterior surface of basis and passing across face of 1st endopodal segment. Setation of both rami reduced in some species and genera; can be variable within species. Rarely P2, 3 and 4 showing asymmetry, as in asymmetrically enlarged coxal setae in P4 of female Gladioferens antarcticus Bayly.
- Female P5 typically with 3-segmented rami; sometimes reduced or modified. Inner margin of 2nd exopodal segment producede into conspicuous spinous process. Endopodal segmentation and setation reduced in some genera.
- Male P5 asymmetrical, coxa and basis distinct; legs typically biramous and both rami primitively 3-segmented, as in Parathalassius. Rami often modified by loss or fusion of segments. Endopod of both legs primitively unmodified, with setation 0-1; 0-1; 2,2,2 but often reduced: sometimes 1-segmented or vestigial, as in Isias. Exopods on both sides often modified by fusion of 2nd and 3rd exopodal segments. Right exopod chelate in some genera, with claw-like 3rd segment opposing spinous process on inner margin of 2nd segment.
- Eggs typically retained in mass on ventral side of urosome or released into water.

Issued from : J.M. Bradford-Grieve in NIWA Biodiversity Memoir 111, 1999. [p.131]. Seta and spine formula of swimming legs P1 to P4.
- P1 - P5 female exopods and endopods 3-segmented; apical spine of exopod strongly serrate; sometimes endopod segments 1 and 2 fused.
- P5 female biramous, natatory, basipods 1 and 2 without setae, exopod segments 1 and 2 with or without 1 outer edge spine, segment 2 with a strong inner spine-like process, exopod segment 3 with or without 2 outer edge spines, 1 terminal serrate spine and 2 or 4 inner edge setae; endopod segments 1 and 2 with 0-1 and 1 inner-edge setae respectively, endopod segment 3 with 4-6 setae.
- P5 male asymmetrical, usually resembling other swimming legs, rami 2 or 3-segmented, right exopod variously transformed into a grasping organ, sometimes endopod atrophied.

Additional information for this family

(1) Centropages Kröyer, 1849

Species, varieties and details

Ref.:

Kröyer, 1849 (in Damkaer & Damkaer, 1979, p.43); Brady, 1878 (p.64); Giesbrecht, 1892 (p.59, 303); Giesbrecht & Schmeil, 1898 (p.53, spp.); Wheeler, 1901 (p.172); Sars, 1902 (1903) (p.74); Esterly, 1905 (p.171); van Breemen, 1908 a (p.92); A. Scott, 1909 (p.112); Sewell, 1929 (p.227); Gurney, 1931 a (p.87); Sewell, 1932 (p.227); Wilson, 1932 a (p.85, spp. Key); Rose, 1933 a (p.183, spp. Key); Mori, 1937 (1964) (p.57, spp. Key); Dakin & Colefax, 1940 (p.91, clé spp.); Farran, 1948 (n°11, p.3); Davis, 1949 (p.53); Brodsky, 1950 (1967) (p.315, spp. Key); Kasturirangan, 1963 (p.31, spp. Key); Tanaka, 1963 (p.7); Vervoort, 1964 b (p.308, Rem.: 5 species Groups); Chen & Zhang, 1965 (p.72, spp. Key); Gonzalez & Bowman, 1965 (p.247); Ramirez, 1966 (p.14); Björnberg, 1972 (p.32, Rem. N); Lee, 1972 (p.1, coupling device); Björnberg & al., 1981 (p.644, clé spp.); Razouls, 1982 (p.420); Gardner & Szabo, 1982 (p.351, Rem.); Zheng Zhong & al., 1984 (1989) (p.243, spp. Key); Mauchline, 1988 (p.711); McKinnon & Kimmerer, 1988 (p.171, 175, Rem.); Razouls, 1993 (p.307); Chihara & Murano, 1997 (p.765, clé spp.); Mauchline, 1998 (p.68: F; p.73: M; p.95: F, M); Mulyadi, 1998 (p.54, spp. Key); Bradford-Grieve & al., 1999 (p.951: spp. Key); Bradford-Grieve,1999 b (p.131, Déf., Rem.); Boxshall & Halsey, 2004 (p.90); Mulyadi, 2004 (p.123, spp. Key in Indonesian waters); Vives & Shmeleva, 2007 (p.464, 465: spp. Key); Brylinski & Courcot (2019, Rem.: p.365, coupling device);

Rem.:

type: Centropages typicus Krøyer, 1849 . Total: 35 spp. (3 doubtful).

Diagnosis after Bradford-Grieve (1999 b, p.131) :
- As for the family definition.
- Urosomr 3-segmented in female.
- Genital segment female usually asymmetrical.
- Urosome male 5-segmented.
- Mx1 inner lobe 1 with 15 spines and setae; inner lobe 2 with 3 setae; inner lobe 3 with 3 setae; basipod 1 with 5 setae; endopod with 4+5 setae, segments 1 and 2 fused to basis; exopod with 9 setae, outer lobe 2 with 1 small seta, outer lobe 1 with 9 setae, 7 of them long.
- Exopod segment 3 of P2 - P4 with 3 outer-edge spines.
- Female P5 basipod 2 not ornamented, exopod segment 2 with a large, straight inner edge spine.
- Male P5 with basipod 2 unornamented; left exopod 2-segmented, segment 1 with 1 outer edge spine; segment 2with 3 outer edge spines and 1 small terminal spine; both endopods as in female; right exopod 3-segmented, in the form of a chela.

Remarks on dimensions and sex ratio:

The mean female size is 1.536 mm (n = 68; SD = 0.4478), and the mean male size is 1.472 mm (n = 64; SD = 0.4405). The size ratio (Male: Female) is 0.958. The sex-ratio (F:M) is 1,03.

(2) Gippslandia Bayly & Arnott, 1969

Species, varieties and details

Ref.:

Bayly & Arnott, 1969 (p.193)

Rem.:

type: Gippslandia estuarina Bayly & Arnott, 1969. Total: 1 sp.

Remarks on dimensions and sex ratio:

In brackish water in the Gippsland lakes of Victoria (SE Australia).

(3) Isias Boeck, 1864

Species, varieties and details

Ref.:

Brady, 1878 (p.62); Giesbrecht, 1892 (p.60, 323); Giesbrecht & Schmeil, 1898 (p.62); Sars, 1902 (1903) (p.78); van Breemen, 1908 a (p.96); Sewell, 1932 (p.232); Rose, 1933 a (p.189); Pillai P., 1975 a (p.325, species Key); Razouls, 1982 (p.431); Dussart & Defaye, 1983 (p.12); Razouls, 1993 (p.307); Mauchline, 1998 (p.70: F; p.73: M); Bradford-Grieve,1999 b (p.145, Def.); Boxshall & Halsey, 2004 (p.88); Vives & Shmeleva, 2007 (p.482)

Rem.:

Type: Isias clavipes Boeck, 1865. Total: 4 spp.

Diagnosis after Bradford-Grieve (1999 b, p.145) :
- As for the family definition.
- Exopod segment 3 of P2 - P4 with 3 outer edge spines.
- Female P5 basipod 2 ornamented with a large distal spine, exopod segment 2 with a medium, curved inner edge spine, exopod segments 2 and 3 may be fused; endopods 1-segmented, with a variable number of setae.
- Male P5 with basipod 2 usually ornamented asymmetrically with large spines or projections; left exopod 2-segmented, segment 1 with 1 outer edge spine, segment 2 with a variable number of spines; endopods reduced or absent; right exopod 2-segmented, segment 1 with 1 outer edge spine, segment 2 may or may not be expanded with 3 outer edge spines and 1 terminal spine.

Remarks on dimensions and sex ratio:

The mean female size is 1,413 mm (n= 3; S= 0,142; Cv= 0,10) and the mean male size is 1,373 mm (n= 3; S= 0,172; Cv= 0,125). The size ratio (M/F) is 0,972 ou 97,2 % (n= 3; S= 0,070; Cv= 0,072)

(4) Parathalassius Dussart, 1986

Species, varieties and details

Ref.:

Dussart, 1986 (p.67, Def.); Bradford-Grieve, 1999b (p.147, Def.)

Rem.:

Type: Parathalassius fagesi Dussart, 1986. Total: 1 sp.
In brackish water.

Definition from Bradford-Grieve (1999 b, p.147) :
- As for the family definition.
- Urosome female 4-segmented.
- Urosome male 5-segmented.
- A1 24-segmented.
- Left A1 male 24-segmented; 22-segmented on the right.
- P1-P4 endopod 3-segmented, with segment 3 supplied with external setae.
- P5 male and female biramous, each ramus 3-segmented.
- P5 male hardly modified compared with other swimming legs.

This genus is nearest ro the freshwater genera Pseudoboeckella and Hemiboeckella but the primitive character of P5 seems to make this genus the most primitive all known of Centropagidae (Dussart, 1986)

(5) Sinocalanus Burckhardt, 1913

Species, varieties and details

Ref.:

Orsi & al., 1983 (p.358)

Rem.:

Fresh-water and in estuaries.
Total: 3 spp.
Characteristics of the genus (After J.J. Orsi, T.E. Bowman, D.C. Marelli & A. Hutchinson, 1983, p.358-359) : 1- Pediger 5 with spine on each posterior corner. 2- Caudal rami without surface spinules. 3- [A2 exopod longer than endopod.] Exopod of A2 longer than endopod 4- A2 distal endopod segment not longer than wide. 5- A2 exopod 2nd segment not distally bilobed. 6- Mxp 2nd basipod segment with modified short setae.

Nota: L.A. Bledzki informs us (29.08.2015) the error in the diagnosis from Orsi & al. (1983, p.358). 7- P5 female with 2nd exopod segment without outer spine ; 1st endopod segment without inner seta. 8- Right P5 male with 1st basipod segment withoutmedial process ; 2nd basipod segment with medial process (except in S. solstitialis).

Remarks on dimensions and sex ratio:

The mean female size is 1.565 mm (n= 6; SD = 0.2827), and the mean male size is 1.458 mm (n = 6; SD = 0.3122). The size ratio (male: female) is 0.937 (n = 3; SD = 0.066). The sex ratio (female:male) is 1.

Additional information for the Centropagidae family ( back to the main information )

Remarks on the adult sizes :

The minimum and maximum values of the adult females are presented in Figure 1 for Centropages (1 to 29) and Isias (30 to 32).

figure 1

The species in the genera Centropages and Isias divide in several groups (Table I) of which the extreme sizes are 0.66 to 3 mm..

Table I: Centropages and Isias : Total length and localisation (E: epipelagic; L: littoral; B: bathypelagic; N : neritic; oc: oceanic)

Species	LG (mm) F, M	Localisation	Depth
C. brachiatus	1,3 à 2,5-3	Cosmop. cold waters, sub-Ant, sub-Trop	E
C. bradyi	-	Cosmop. sub-Ant, cold temperate	E - B
C. abdominalis	1,5 à 2,10	Warm temperate , sub-Arct, Arct ± brackish	L
C. aucklandicus	-	Cold temperate , sub-Antarct ?	L
C. calaninus	-	Cosmop. Tropic, cold temperate	E
C. caribbeanensis	-	(sub)- Tropic
C. chierchiae	-	sub- Tropic	E
C. elegans	-	Tropic
C. gracilis	-	Tropic	E
C. longicornis	-	Tropic, sub-Tropic	E
C. tenuiremis	-	Tropic, cold waters Pacif NW	N
C. typicus	-	Cold temperate, sub-Tropic	E, N, B
C. violaceus	-	Cosmop Tropic & sub-Tropic	E, oc
C. alcocki	± 1 à ± 1,5	Tropic, ± brackish	L
C. australiensis	-	Cold temperate	N
C. brevifurcus	-	Tropic ± brackish
C. dorsispinatus	-	Tropic	L
C. halinus	-	sub-Tropic, hyperhalin	L
C. hamatus	-	Cold temperate
C. karachiensis	-	Tropic	L - E
C. kröyeri	-	Tropic, warm temperate	E
C. natalensis	-	sub-Tropic
C. orsinii	-	Tropic	E
C. sinensis	-	Tropic
C. trispinosus	± 1 à ± 1,5	Tropic	L
I. clavipes	-	sub-Tropic, cold temperate	N
I. tropica	-	Tropic ± brackish	L
I. uncipes	-	Tropic, euryhalin	L
C. ponticus ± 1	± 1	Warm temperate	L

Two species show high variabilities, sizes between 1.3 and 3 mm, and correspond to cosmopolitan sub-Antarctic and temperate cold waters forms, or more or less deep subtropical waters.
Eleven species measure between 1,5 and 2,1 mm (37,93%) and are generally tropical or sub-tropical cosmopolites and/or in colder waters.
Fifteen species, measuring between 1.3 and 1.5 mm, live mostly in tropical and warm-temperate waters. One species ( C. ponticus ), in any case if it does not correspond to a variety of C. kröyeri, shows sizes slightly smaller than 1 mm in both females and males.