Corresponding author: Viatcheslav N. Ivanenko (
Academic editor: D. Defaye
Re-study of the type species of the genus
Ivanenko VN, Lee J, Chang CY, Kim I-H (2019) Description of
Cyclopoids of the family
In June 2018 the Korea Institute of Ocean Science and Technology (
Samples of the meiobenthos around the hydrothermal vents of the Onnuri Vent Field (
Prior to description of the species, selected copepod specimens were soaked in lactic acid. Dissections were performed using the reversed slide method of
Spine and setal formulae of legs 1-4 in
Coxa | Basis | Endopod | Exopod | |
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Leg 1 | 0-1 | 1-I | 0-1;0-1;1,2,3 | I-0;I-1;III,I,4 |
Leg 2 | 0-1 | 1-0 | 0-1;0-2;1,2,3 | I-0;I-1;III,I,5 |
Leg 3 | 0-1 | 1-0 | 0-1;0-2;1,II,I+2 | I-0;I-1;III,I,5 |
Leg 4 | 0-1 | 1-0 | 0-1;0-1+I;I,II,II | I-0;I-1;II,I,5 |
The hydrothermal vent field of
Holotype (♀, MABIK CR00244723) and paratypes (6 ♀♀, 6 ♂♂, MABIK CR00244724) have been deposited in the MABIK. Dissected paratypes (2 ♀♀, 1 ♂) are retained in the collection of the last author. All type specimens collected on 23 June 2018 from the type locality.
Body (Fig.
Rostrum (Fig.
Antenna (Fig.
Labrum weak, easily destroyed. Mandible (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (Fig.
Legs 1–4 (Figs
Leg 5 (Fig.
Leg 6 (Fig.
Body (Fig.
Rostrum as in female. Antennule (Fig.
Mandible and other mouth appendages as in female.
Legs 1, 2, and 4 also as in female. Leg 3 sexually dimorphic; third endopodal segment (Fig.
Leg 5 as in female. Leg 6 (Fig.
The specific name
Females and males from the type locality dissected by A.G. Humes and marked as
Body as in original description. Differs from
Caudal ramus (Fig.
Antennule (Fig.
Antenna (Fig.
Mandible (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (Fig.
Legs 1–4 (Fig.
Leg 5 (Fig.
Differs from
Caudal ramus (Fig.
Morphological differences, distributions and habitats among species of the
Characters\ Species |
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♀ Caudal ramus, L/W ratio | 7.6 | 4.0 | about 4 | 11.0 | 8.9 | 8 | – | 8 | 15.5 |
Segments of ♀ antennule | 15 | 15 | 12 | 14 | 14 | 7 | 8 | 8 | 8 |
Armature of antenna | 1-1-5-7 | 1-1-5-6 | 0-1-4-7 | 0-1-5-7 | 0-1-5-7 | 0-1-1-5 | 0-1-1-6 | 0-1-1-6 | 1-9 |
Inner seta on basis of mandible | Present | Present | Present | Absent | Absent | Absent | Absent | Present | Absent |
Armature of mandibular exopod | 1-1-1-2 | 1-1-2 | 1 seta | 0-0-2 | 0-0-2 | 1-1-1 | 1-2 | 1-1-1 | 2 |
Armature of mandibular endopod | 3-5 | 2-4 | 4 | 2-4 | 2-4 | 5 | 4 | 4 | 4 |
Setae on maxillular basis | 4 | ? | 3 | 4 | 4 | 4 | – | – | 3 |
Setae on maxillular exopod | 4 | 4 | 3 | 4 | 4 | 4 | – | – | 4 |
Setae on maxillular endopod | 6 | ? | 5 | 5 | 5 | – | – | – | 4 |
Setae on maxilliped segments | 5-2-1-1-1-1-4 | 4-2-1-1-1-1-4 | 3-2-1-1-3 | 3-2-1-1-1-1-3 | 3-2-1-1-1-1-3 | 0-0-0-1+spine | 0-0-0-1 | 1 | 1-1 |
Outer element of 3rd endopodal segment of leg 1 | Seta | Seta | Spine | Seta | Seta | Spine | Spine | Spine | None |
Armature of 3rd endopodal segment of leg 3 | 3 spines + 3 setae | 2 spines + 4 setae | 2 spines + 4 setae | 3 spines + 3 setae | 3 spines + 3 setae | 4 spines + 2 setae | 4 spines + 2 setae | – | 2 spines + 2 setae |
Spines on 3rd exopodal segment of leg 3 | 4 | 3 | 4 | 4 | 4 | 4 | 4 | – | 4 |
Armature on 2nd endopodal segment of leg 4 | 1 spine + 1 seta | 2 setae | 2 setae | 1 spine + 1 seta | 1 spine + 1 seta | 1 spine + 1 seta | 1 spine + 1 seta | – | 1 spine + 1 seta |
Armature of exopod of ♀ leg 5 | I, I+1+I | II, 1+I | I, I+1+I | I, I+1+I | I, I+1+I | I, I+1+I | I, I+1+I | I, I+1+I | 1+1+I |
Armature of exopod of ♂ leg 5 | I-1; I+1+I, 1 | Unknown | As in female | I, I+1+I, 1 | As in female | I-1; I+1+I | Unknown | Unknown | I, I+1+I, 1 |
Distributions (habitats) | Mediterranean & Atlantic (anchihaline caves) | Australia |
Norway (shallow water) | Northeast Pacific (hydrothermal vent area) | Indian Ocean (hydrothermal vent area) | Arctic (depth 8–529 m) | Arctic (depth 156–449 m) | Arctic (depth 256 m) | Arctic (depth 3211 m) |
References | Jaume & Boxshall, 1996 | Karanovic, 2008 | Sars, 1913 | Humes, 1998 |
This paper |
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Data here show that the sexual dimorphism in leg 3 occurs in
Although the two species of
1 | Antennule of female 7 or 8-segmented; maxilliped 1 to 4-segmented |
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– | Antennule of female 12 to15-segmented; maxilliped 5 to7-segmented |
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2 | Antenna 2-segmented; third endopodal segment of leg 3 armed with 2 spines and 2 setae; third endopodal segment of leg 1 without outer element |
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– | Antenna 4-segmented; third endopodal segment of leg 3 armed with 4 spines and 2 setae; third endopodal segment of leg 1 with outer spine |
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3 | Mandibular basis with inner seta; maxilliped 1-segmented |
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– | Mandibular basis without inner seta; maxilliped 4-segmented |
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4 | Mandibular endopod armed with 5 setae; terminal segment of maxilliped with 1 spine and 1 seta |
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– | Mandibular endopod armed with 4 setae; terminal segment of maxilliped with 1 seta only |
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5 | Second endopodal segment of leg 4 armed with 2 setae; third endopodal segment of leg 3 armed with 2 spines and 4 setae |
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– | Second endopodal segment of leg 4 armed with 1 spine and 1 seta; third endopodal segment of leg 3 armed with 3 spines and 3 setae |
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6 | Antenna with armature formula 0-1-4-7; mandibular endopod 1-segmented, with 4 setae; maxilliped 5-segmented |
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– | Antenna with armature formula 1-1-5-6; mandibular endopod 2-segmented, with 2 and 4 setae on first and second segments, respectively; maxilliped 7-segmented |
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7 | Antenna with armature formula 1-1-5-7; mandibular basis with inner seta; mandibular endopod with 3 and 5 setae on first and second segments, respectively; first segment of maxilliped with 5 setae |
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– | Antenna with armature formula 0-1-5-7; mandibular basis lacking inner seta; mandibular endopod with 2 and 4 setae on first and second segments, respectively; first segment of maxilliped with 3 setae | |
8 | Leg 5 sexually dimorphic, with exopod bearing 3 spines + 1 seta in female and 3 spines + 2 setae in male; length/width ratio of caudal ramus 11:1 in female and 8.5:1 in male |
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– | Leg 5 of both sexes with exopod bearing 3 spines + 1 seta; length/width ratio of caudal ramus 8.9:1 in female and 6.1:1 in male |
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We thank the captain and crew members of the R/V ISABU for help and support during the cruises. This research was supported by the project “Understanding the deep-sea biosphere on seafloor Hydrothermal Vent in the Indian Ridge” of the Korea Institute of Marine Science and Technology Promotion (KIMST) funded by Ministry of Oceans and Fisheries, Korea (20170411) and by