Cyclopoida ( Order )
Speleoithonidae Rocha & Iliffe, 1991 ( Cyclopoida )
Ref.: Rocha & Iliffe, 1991 (p.167, 175); Boxshall & Halsey, 2004 (p.661: Def.)
Rem.: 1 G: Speleoithona.

For Boxshall & Halsey (2004, p.661) this family was distinguished from the Oithonidae on the basis of the plesiomorphic state of P5, which retains a discrete protopodal segment linked by an intercoxal sclerite in both sexes and exhibits sexual dimorphism in its exopodal setation pattern. It also differs from oithonids in the presence of a claw-like setal element fused to the basis of the Mx2.
Mainly inhabitant anchialine caves.
Family Speleoithonidae - Plate 1Issued from : G.A. Boxshall & S.H. Halsey in The Ray Society, 2004, N°166, Part II. [p.662, Fig.218].
A, Speleoithona eleutherensis female; B, Mx1; C, Md; D, A2; E, P5; F, male P5.
From da Rocha & Ilife, 1991.

Family Speleoithonidae - Plate 2Issued from : G.A. Boxshall & S.H. Halsey in The Ray Society, 2004, N°166, Part II. [p.661].
Armature formula of swimming legs P1 to P4.
Nota: Swimming legs P1 to P4 biramous, with 3-segmented rami. P1 to P4 joined by intercoxal sclerites. Inner seta on basis of P1 present. Inner coxal seta present in P1 only.
- Armature of legs P1 to P4 often secondarily reduced.
- P5 in both sexes with single protopodal segment and 1-segmented exopod. Intercoxal sclerite present. Outer protopodal seta long, situated on distal surface of segment adjacent to free exopodal segment. Exopod bearing single apical seta in female; apical seta plus 2 inner margin setae in male.
- P6 represented by 1 seta on genital operculum of female; by 2 setae in male.
(1) Speleoithona Rocha & Iliffe, 1991
Ref.: Rocha & Iliffe, 1991 (p.168)
Rem.: Total: 3 spp.
Remarks on dimensions and sex ratio:
The mean female size is 0.273 mm (n = 6; SD = 0.0186) and the mean male size is 0.257 mm (n = 6; SD = 0.0242). The size ratio (Male / Female) is 0.94, or 94 %. The sex ratio (female / male) is 1.

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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 February 23, 2024]

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Marine Planktonic Copepods

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