Research Article |
Corresponding author: Tomislav Karanovic ( tomislav.karanovic@gmail.com ) Academic editor: Danielle Defaye
© 2020 Tomislav Karanovic.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Karanovic T (2020) Four new Cyclopina (Copepoda, Cyclopinidae) from South Korea. ZooKeys 992: 59-104. https://doi.org/10.3897/zookeys.992.54856
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Copepods are well studied in South Korea, with the exception of marine non-parasitic cyclopoids, and especially cyclopinids; only three species were found so far here, and only one of them is endemic. A survey of intertidal interstitial faunas from sandy beaches revealed four endemic members of the genus Cyclopina Claus, 1863, which represents the first record of the largest cyclopinid genus in South Korea. A detailed study of their morphology revealed numerous differences, including in rarely studied cuticular organs. Some of these micro-characters could easily be homologised and showed little intraspecific variability, which might prove invaluable for matching sexes and reconstructing phylogenetic relationships. Cyclopina busanensis sp. nov. is described from both sexes collected near Busan (South Coast of South Korea), and is most similar to the only congener from Japan: C. kiraensis Horomi, 1984. Cyclopina koreana sp. nov. is described from both sexes collected near Gangneung (East Coast), and has no close relatives among currently known species. Cyclopina curtijeju sp. nov. is described from two females from Jeju (off South Coast); it is possibly closely related to C. smirnovi Herbst, 1982, but the latter is known from a single male from the Russian Far East. Cyclopina wido sp. nov. is described from both sexes from Wido (West Coast), and shows numerous reductions in segmentation and armature of appendages, most of them probably a consequence of its diminutive size. A table of 26 discrete and continuous characters commonly used in the taxonomy of this group is provided for 48 valid species and subspecies of Cyclopina.
Cyclopoida, intertidal zone, meiofauna, new species, stygofauna, taxonomy
Marine cyclopoids, and especially cyclopinids, are poorly studied globally because their diversity is highest in marginal habitats, such as intertidal interstitial and anchialine caves, or in highly inaccessible abyssal and hadal depths. Only three cyclopinids have been reported so far from Korea: Cyclopinoides orientalis Chang, 2011; Cyclopinopsis deformata Lee & Chang, 2019; and Paracyclopina nana Smirnov, 1935. The first species was described by
Copepods are generally relatively well studied in South Korea, both as free-living forms in marine (
Cyclopina is the oldest and type cyclopinid genus, as well as the largest by number of species (
Cyclopinid systematics at large is also still in a state of flux (
Aims of this study were to describe four new species from South Korea in fine detail, asses their affinities using morphological characters, provide a global list of valid Cyclopina species and subspecies, and assemble a table of discrete and morphometric morphological characters most commonly used to identify species in this genus.
All specimens were collected from the intertidal zone in four localities in South Korea, using the Karaman-Chappuis method. This sampling technique involves digging a hole on the beach down to the water level and then decanting the inflowing interstitial water and filtering it through a plankton net (mesh size 30 μm). All samples were fixed in 99% ethanol, sorted in the laboratory also in 99% ethanol, using an Olympus SZX12 dissecting microscope with PLAPO objectives and magnification of up to 200 ×. Locality data and number of specimens are listed for each species separately and all material is deposited in the National Institute of Biological Resources (NIBR), Incheon, South Korea.
Some specimens were dissected and mounted on microscope slides in Faure’s medium (see
The terminology for morphological characters mostly follows
South Korea, South Coast, Busan, Sonjong Beach, intertidal sand, 35°10.741'N, 129°12.317'E.
Holotype ovigerous female dissected on one slide, collected from the type locality, 6 May 2016, leg. T. Karanovic. Paratypes: one male (allotype) and two females dissected on one slide each, seven females (one ovigerous) and five copepodids in alcohol, and five females on one SEM stub (together with specimens of other three species described here; row no. 2), all collected from the type locality, 6 May 2016, leg. T. Karanovic.
The species name refers to the type locality. It is an adjective for place, made with the Latin suffix -ensis.
Female (based on holotype and seven paratypes). Body length, excluding caudal setae, from 515 to 535 μm. Colour of preserved specimens light brown, nauplius eye not visible (Fig.
Cyclopina busanensis sp. nov., paratype female 1, SEM photographs, all in lateral view A habitus B distal part of antennula C anterior part of cephalothorax with rostrum D central part of cephalothoracic shield E postero-lateral corner of cephalothoracic shield F tergite of first pedigerous somite (= first free prosomite), mostly covered by postero-lateral corner of cephalothoracic shield G tergite of second pedigerous somite H tergite of third pedigerous somite.
Cyclopina busanensis sp. nov., paratype female 1, SEM photographs, all in dorsal view A tergite of fourth pedigerous somite B fifth leg C genital double-somite (=fused second and third urosomites) D sixth leg E detail of posterior part of genital double-somite F fourth and fifth urosomites G sixth urosomite (= anal somite) and caudal ramus H detail of sixth urosomite.
First urosomite
(Figs
Genital double-somite
(Figs
Cyclopina busanensis sp. nov., paratype female 2, SEM photographs, all in dorsal view A habitus B anterior part of cephalothorax C posterior part of cephalothorax D free prosomites E anterior part of genital double-somite F posterior part of genital double-somite G fourth and fifth urosomite H sixth urosomite.
Caudal rami
(Figs
Antennula
(Figs
Antenna
(Fig.
Mandibula
(Fig.
Maxillula
(Fig.
Maxilla
(Fig.
Maxilliped
(Fig.
Swimming legs
(Figs
Cyclopina busanensis sp. nov., line drawings A–E holotype female F allotype male: A first swimming leg B second swimming leg C third exopodal segment of third swimming leg D third endopodal segment of third swimming leg E fourth swimming leg F third endopodal segment of fourth swimming leg.
Fifth leg
(Figs
Sixth leg
(Fig.
Male (based on allotype). Body length 503 μm. Urosome (Fig.
Caudal rami
(Fig.
Antennula
(Fig.
Antenna, mandibula, maxillula, maxilla, maxilliped
, and all four swimming legs as in female. Third endopodal segment of fourth leg (Fig.
Fifth leg
(Fig.
Sixth leg
(Fig.
Cuticular organs on the cephalothorax (Figs
South Korea, East Coast, Gangneung, small beach, intertidal sand, 37°47.824'N, 128°55.085'E.
Holotype female dissected on one slide, collected from the type locality, 29 March 2013, leg. T. Karanovic.
Paratypes : two males and one female dissected on one slide each; three males, two females, and four copepodids in alcohol; one male and two females on one SEM stub (together with specimens of other three species described here; row no. 4); all collected from the type locality, 29 March 2013, leg. T. Karanovic.
The species name refers to South Korea. It is an adjective, agreeing in gender with the feminine genus name.
Cyclopina koreana sp. nov., paratype female 1, SEM photographs, all in dorsal view A habitus B second pedigerous somite C third pedigerous somite D first urosomite E genital double-somite and fourth urosomite F anterior medial pore on genital double-somite G fifth and sixth urosomites H caudal ramus.
Female (based on holotype and three paratypes). Body length from 620 to 635 μm. Colour of preserved specimens yellowish, nauplius eye not visible (Fig.
Cyclopina koreana sp. nov., SEM photographs A–E paratype male 1, ventral view F–H paratype female 2, lateral view: A habitus B distal part of antennula C fourth swimming leg D fourth and fifth urosomites E sixth urosomite F tergite of fourth pedigerous somite G anterior part of urosomite, with fifth and sixth legs H fifth and sixth urosomites.
First urosomite
(Figs
Genital double-somite
(Figs
Caudal rami
(Figs
Antennula
(Fig.
Antenna
(Fig.
Mandibula
(Fig.
Maxillula
(Fig.
Maxilla
(Fig.
Maxilliped
(Fig.
Swimming legs
(Fig.
Fifth leg
(Fig.
Sixth leg
(Fig.
Male (based on allotype and two other paratypes). Body length from 440 to 500 μm. Habitus (Fig.
Caudal rami
(Fig.
Antennula
(Figs
Cyclopina koreana sp. nov., line drawings A–E holotype female F–H allotype male: A third endopodal segment of first swimming leg B third exopodal segment of first swimming leg C third exopodal segment of second swimming leg D third endopodal segment of second swimming leg E fourth swimming leg F antennula G third endopodal segment of fourth swimming leg H third exopodal segment of fourth swimming leg.
Antenna
, mandibula, maxillula, maxilla, maxilliped, and all four swimming legs (Fig.
Fifth leg
(Fig.
Sixth leg
(Fig.
Except for small differences in body size no other forms of variability were observed, but some specimens were damaged (e.g., with some setae broken off; see Fig.
South Korea, South Coast, Jeju Island, Gwangchigi Beach near Seongsan Sunrise Peak, 33°27.122'N, 126°55.481'E.
Holotype female dissected on one slide, collected from the type locality, 14 April 2014, leg. T. Karanovic. Paratype female on an SEM stub (together with specimens of other three species described here; row no. 3), collected from the type locality, 14 April 2014, leg. T. Karanovic.
The species name is composed of the Latin adjective curtus (= short), referring to its short caudal rami, and the name of the type locality (Jeju). It should be treated as a noun (gender feminine) in apposition to the generic name.
Female (based on holotype and one paratype). Body length 400 μm. Colour (Fig.
Cyclopina curtijeju sp. nov., paratype female, SEM photographs, all in lateral view A anterior part of cephalothoracic shield B posterio-lateral corner of cephalothoracic shield C tergite of second pedigerous somite D tergites of third and fourth pedigerous somites E genital double-somite F sixth leg G fourth and fifth urosomites H sixth urosomite and caudal rami.
Genital double-somite
(Fig.
Caudal rami
(Fig.
Antennula
(Fig.
Cyclopina curtijeju sp. nov., holotype female, line drawings A caudal ramus, lateral view B distal part of antennula, without armature C coxa of mandibula D endopod of maxillula E endopod of maxilla F endopod of maxilliped G third exopodal segment of first swimming leg H third endopodal segment of first swimming leg I basis and endopod of second swimming leg J fourth swimming leg K fifth leg.
Antenna and mandibula
(Fig.
Maxillula
(Fig.
Maxilla
(Fig.
Maxilliped
(Fig.
Swimming legs
(Fig.
Fifth leg
(Fig.
Sixth leg
(Fig.
Male unknown.
Only two females were examined, both partly damaged, one in detail with a light microscope (holotype), and the other with a scanning electron microscope (paratype), so variability could not be properly assessed. However, the paratype female was also beforehand examined with a light microscope (although without dissection) and no variability was observed in the most important diagnostic characters (caudal rami length, antennula segmentation, swimming legs armature, or fifth leg proportions); mouth appendages could not be examined without dissection.
South Korea, West Coast, Wido Island, small beach, intertidal sand, 35°35.089'N, 126°15.196'E.
Holotype ovigerous female dissected on one slide, collected from the type locality, 12 April 2013, leg. T. Karanovic.
Paratypes : one male (allotype) dissected on one slide; one female on one SEM stub (together with specimens of other three species described here; row no. 1); both collected from the type locality, 12 April 2013, leg. T. Karanovic.
The species name refers to its type locality (Wido). It should be treated as a noun (gender feminine) in apposition to the generic name.
Female (based on holotype and one paratype). Body length of holotype 327 μm, that of paratype 323 μm. Colour of preserved specimens yellowish, nauplius eye not visible (Fig.
Cyclopina wido sp. nov., paratype female 1, SEM photographs, all in dorsal view A posterior part of cephalothorax B first and second pedigerous somites C third and fourth pedigerous somites D first urosomite E sixth leg F posterior part of genital double-somite and fourth urosomite G hyaline fringe of fifth urosomite and sixth urosomite H caudal rami.
First urosomite
(Fig.
Genital double-somite
(Figs
Caudal rami
(Figs
Antennula
(Fig.
Antenna
(Fig.
Cyclopina wido sp. nov., line drawings A–J holotype female K–M allotype male: A antenna, without apical armature B mandibula C maxillular palp D endopod of maxilla E last four endopodal segments of maxilliped F first swimming leg G third exopodal segment of second swimming leg H endopod of second swimming leg I fourth swimming leg J fifth leg K endopod of first swimming leg L third endopodal segment of fourth swimming leg M third exopodal segment of fourth swimming leg.
Mandibula
(Fig.
Maxillula
(Fig.
Maxilla
(Fig.
Maxilliped
(Fig.
Swimming legs
(Fig.
Fifth leg
(Fig.
Sixth leg
(Fig.
Male (based on allotype). Body length 305 μm. Habitus similar to female, but slightly slenderer. Urosome (Fig.
Caudal rami
(Fig.
Antennula
(Fig.
Antenna, mandibula, maxillula, maxilla, maxilliped
, and all four swimming legs (Fig.
Fifth leg
(Fig.
Sixth leg
(Fig.
Only one male and two females were examined, so variability could not be properly assessed. One female was examined in detail with a light microscope (holotype), and the other with a scanning electron microscope (paratype). However, the paratype female was also beforehand examined with a light microscope (although without dissection) and no variability was observed in the most important diagnostic characters (caudal rami length, antennula segmentation, swimming legs segmentation and armature, or fifth leg proportions); mouth appendages could not be examined without dissection. Male characters that are not sexually dimorphic show only minute differences from female characters in proportions of somites, segments, or armature.
Four new species from South Korea share a number of characters that are considered important in cyclopoid taxonomy and systematics, such as free first pedigerous prosomite, extended postero-lateral corners of the cephalothoracic shield, T-shaped copulatory duct and ovoid seminal receptacles on the completely fused genital double-somite, very short anal operculum, relatively short caudal rami armed with only six setae, short female antennula (10- or 11-segmented) with longest sixth segment, four-segmented antenna with armature formula of the last three segments 1/4/7, four-segmented mandibular exopod with armature formula 1/1/1/2, one-segmented maxillular exopod armed with four setae, maxillipedal armature formula 4/2/2/0/0/1/3, three-segmented exopods of all swimming legs with spine formula of the third segments 4/4/4/3, three-segmented endopods of second to fourth legs with seta formula of the third segments 6/6/5, two-segmented female fifth leg with two spines and central seta on the second segment, and male fifth legs (in three species with known males) with two additional medial setae on the second segment. All of these characters are within the currently recognised boundaries of the genus Cyclopina (see
Cuticular organs (sensilla and pores) on somites certainly show some differences between the four new South Korean species described here, but some of these rarely studied micro-characters could easily be homologised (especially on urosomites) and showed little intraspecific variability. This could be invaluable in future studies trying to match opposite sexes, especially because numerous Cyclopina species are known after only one sex (
Cyclopina busanensis is probably most similar to the Japanese C. kiraensis Horomi, 1984, described from the Pacific Coast of Honshu (
List of selected character states for valid species and subspecies of the genus Cyclopina Claus, 1963. Abbreviations used: ?, unknown; +, present; –, absent; A, anterior; A1, antennula; A2, antenna; AnSo, anal somite; Bp, basis; Cr, caudal ramus; Enp, endopod; Exp, exopod; L, length; Md, mandibula; Mxl, maxillula; Mxp, maxilliped; P, posterior; P1, first leg; P4, fourth leg; P5, fifth leg; P6, sixth leg; W, width. See text for more details.
Cr, L/W | Cr /AnSo | medial seta/Cr | Cr, medial/dist. lateral seta | Cr, medial/dorsal seta | Cr, prox. lat. seta position | Cr, space between rami | Female A1, segmentation | A2, no. of exopodal setae | A2Bp, no. of medial setae | A2Enp2, no. of setae | MdEnp, armature formula | MxlEnp, no. of setae | MxpEnp, armature formula | P1Enp, no. of segments | P1Enp, no. of setae | P4Exp3, L/W | P4Exp3, no of setae | P4Enp3, L/W | P4Enp, lanceolate setae | P5, Exp/Bp | P5Exp, L/W | P5, lateral spine/Exp | P5Exp, lateral/medial spine | Male P5, no. of medial setae | Male P6, medial spine | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
C. adelphe Karanovic, 2008 | 3 | 1.2 | ? | ? | ? | A | 2.2 | 11 | 1 | 2 | 5 | 3/4 | 6 | 0/0/1/3 | 3 | 7 | ? | 5 | 1.4 | – | 1.9 | 2.5 | 0.4 | 0.7 | ? | ? |
C. adriatica Petkovski, 1955 | 1.6 | 1 | 3 | 1.5 | 1.1 | P | 0.3 | 10 | 1 | 1 | 5 | 3/6 | 7 | 0/0/1/3 | ? | 8 | ? | 5 | ? | ? | 2.1 | 2.2 | 0.9 | 1 | ? | ? |
C. americana Herbst, 1982 | 1.5 | 1 | 2.7 | 2 | 1.5 | P | 0.5 | 10 | 0 | 1 | 4 | 3/6 | ? | 0/0/1/2 | 3 | ? | 1.5 | 5 | 1.5 | – | 1.5 | 2 | 1.3 | 2.5 | 1 | – |
C. amita Karanovic, 2008 | 1.8 | 0.9 | 2.3 | 2.2 | 1.2 | P | 0.4 | 11 | 1(0) | 1(2) | 4(5) | 3/4 | 6 | 0/0/0/3 | 3 | 8 | 1.7 | 5 | 1.5 | – | 1.4 | 2.1 | 1.3 | 2.2 | 2 | – |
C. arenosa Lotufo, 1994 | 3.4 | 1.4 | 0.8 | 1.4 | 1.2 | A | 0.6 | 10 | 2 | 1 | 5 | 3/5 | 7 | ? | 2 | 8 | 1.4 | 5 | ? | ? | 1.2 | 1.5 | 1 | 1.2 | ? | ? |
C. balearica (Jaume & Boxshall, 1996) | 2.9 | 1.2 | 1.7 | 2.9 | 1.7 | A | 0.7 | 10 | 2 | 1 | 5 | 3/6 | 7 | 0/0/4 | 3 | 7 | 1.6 | 5 | 1.5 | – | 1.4 | 2.4 | 0.9 | 1.2 | 2 | + |
C. brachystylis Sars, 1921 | 1.5 | 0.9 | 2.7 | 1.5 | 1.4 | P | 0.2 | 10 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | 1.2 | 2.2 | 1.3 | 2 | ? | ? |
C. brevifurca Sars, 1913 | 0.8 | 0.5 | 4.6 | 1.1 | 1 | P | 0.3 | 12 | 1 | 1 | 4 | 3/6 | 7 | 1/1/2 | 3 | 8 | 1.9 | 5 | 1.7 | – | 1.4 | 2.5 | 1.5 | 1.7 | ? | ? |
C. busanensis sp. nov. | 3.7 | 2 | 1.2 | 1.6 | 1.5 | A | 0.5 | 10 | 1 | 1 | 4 | 3/5 | 7 | 0/0/1/3 | 3 | 8 | 1.5 | 5 | 1.6 | – | 1.3 | 1.6 | 1.2 | 1.6 | 2 | + |
C. caiala Lotufo & Rocha, 1991 | 1.7 | 0.8 | 2.6 | 1.7 | 2 | P | 0.2 | 10 | 1 | 1 | 5 | 3/6 | 7 | 1/0/1/3 | 3 | 8 | 1.3 | 5 | 1.3 | + | 1.5 | 1.6 | 0.5 | 1 | 0 | + |
C. caissara Lotufo, 1994 | 1.5 | 0.9 | 3.1 | 1.2 | 1.3 | P | 0.2 | 12 | 1 | 1 | 5 | 3/6 | 7 | 0/0/1/4 | 3 | 8 | 1.8 | 5 | 1.8 | – | 0.9 | 2 | 1.7 | 6.5 | 2 | + |
C. campechana (Suarez & Almeyda, 2015) | 1.2 | 1 | 3 | 1.5 | 1.3 | P | 0.5 | 10 | 1 | 1 | 5 | 3/5 | 7 | 0/0/1/4 | 3 | 8 | 1.4 | 5 | 1.4 | – | 1.5 | 2 | 0.9 | 2.4 | 2 | + |
C. caroli Lotufo, 1994 | 1.5 | 1.1 | 3.5 | 2.2 | 2.3 | P | 0.3 | 10 | 2 | 1 | 5 | 3/5 | 7 | 0/0/1/4 | 3 | 8 | 1.5 | 4 | 1.4 | + | 1.7 | 1.7 | 1 | 1.3 | 1 | + |
C. confusa (Ivanenko & Defaye, 2004) | 3.7 | 1.3 | 1.5 | 1.7 | 1.7 | A | 0.6 | 10 | 2 | 1 | 5 | 3/6 | 7 | 0/0/1/4 | 3 | 8 | 1.4 | 5 | 1.5 | – | 1.3 | 2.1 | 0.8 | 1.4 | 2 | + |
C. crassisetosa Herbst, 1953 | 3.7 | 1.4 | 1.1 | 1.9 | 0.7 | P | 0.3 | 10 | 0 | 1 | 4 | 3/? | 7 | 0/0/1/3 | 3 | ? | ? | ? | 1.4 | – | 1.6 | 1.5 | 1 | 1 | ? | ? |
C. curtijeju sp. nov. | 1.3 | 1.2 | ? | ? | ? | P | 0.3 | 11 | 2 | 1 | 4 | 3/6 | 7 | 0/0/1/3 | 3 | 8 | 1.5 | 5 | 1.6 | + | 1.5 | 1.9 | 1.3 | 1.8 | ? | ? |
C. dorae Lotufo, 1994 | 1.9 | 1.1 | 1.1 | 1.3 | 0.8 | P | 0.6 | 10 | 2 | 1 | 5 | 3/5 | 7 | 0/0/1/4 | 3 | 8 | 1.5 | 5 | ? | ? | 1.3 | 2 | 0.7 | 0.9 | ? | ? |
C. ensifera Grandori, 1925 | 3 | 1.4 | 1.7 | 1.6 | 1.4 | P | 0.3 | 10 | 1 | 1(0) | 5 | 3/6 | 7 | 0/0/1/3 | 3 | 8 | 1.3 | 5 | 1.7 | + | 2 | 2 | 1.1 | 1.1 | 0 | – |
C. esilis Brian, 1938 | 3 | 1.5 | 1.6 | 2.5 | 1.5 | A(P) | 0.6 | 10 | 1(0) | 1(0) | 5 | 3/6 | 7 | 0/0/1/3(4) | 3 | 8 | 1.8 | 5 | 2 | +(–) | 1.4 | 1.7 | 1.1 | 2.8 | 2 | +(–) |
C. gracilis Claus, 1863 | 4 | 2 | 0.8 | 1.2 | 0.8 | A | 0.8 | 10 | 1 | 1 | 4 | 2/6 | 6 | 0/1/2 | 3 | 8 | 1.8 | 5 | 1.4 | – | 1.2 | 1.3 | 1.5 | 1.2 | 1(0) | + |
C. hadzii Petkovski, 1955 | 2.8 | 1.7 | 0.7 | 1.7 | 1 | A | 0.5 | 10 | 1 | 1 | 3 | ? | ? | ? | ? | 7 | ? | 5 | ? | ? | 1.4 | 1.9 | 1 | 1 | 1 | ? |
C. kasignete Karanovic, 2008 | 2.3 | 0.9 | 1.5 | 1.9 | 0.9 | P | 0.4 | 10 | 1 | 1 | 5 | 3/6 | 6 | 0/0/0/3 | 3 | 8 | ? | 5 | 1.4 | – | 1.7 | 2.1 | 1.1 | 1.2 | 0 | + |
C. kasis Karanovic, 2008 | 2.4 | 1.2 | 2.2 | 1.6 | 1.6 | P | 0.2 | 9 | 1 | 1 | 5 | 2/4 | 6 | 0/0/3 | 3 | 8 | ? | 5 | 1.5 | – | 1.5 | 1.6 | 1.1 | 2.1 | ? | ? |
C. kieferi elongata Herbst, 1953 | 3.3 | 1.5 | 1.7 | 1.9 | 1.4 | A | 0.4 | 10 | 0 | 1 | 4 | 3/6 | 7 | 0/0/1/4 | 3 | 8 | ? | 5 | 1.6 | + | 1.8 | 1.7 | 1.4 | 1.5 | ? | ? |
C. kieferi Schäfer, 1936 | 1.5 | 1 | 2.9 | 1.8 | 1.9 | P | 0.3 | ? | 1 | 1 | 5 | 3/6 | 7 | 0/0/1/3 | 3 | 8(7) | ? | 5 | 1.5 | + | 1.9 | 2.1 | 1.2 | 2.5 | 1(0) | ? |
C. kiraensis Hiromi, 1984 | 3.3 | 1.2 | 1 | 1.4 | 0.8 | A | 0.6 | 10 | 1 | 1 | 5 | 3/6 | 7 | 0/0/1/3 | 3 | 8 | 1.5 | 5 | 1.4 | + | 1.1 | 1.8 | 1.5 | 1.7 | 2 | + |
C. koreana sp. nov. | 3.5 | 1.6 | 0.9 | 1.7 | 0.9 | A | 1.4 | 10 | 2 | 1 | 4 | 3/6 | 7 | 0/0/1/3 | 3 | 8 | 1.6 | 4 | 1.7 | + | 1.3 | 1.6 | 1 | 1.3 | 2 | – |
C. laurentica Nicholls, 1939 | 0.5 | 0.5 | 8.2 | 1.4 | ? | P | 0.3 | 12 | 0 | 1 | 3 | 3/5 | 7 | 0/0/0/4 | 3 | 8 | 1.5 | 5 | 1.6 | – | 1.2 | 1.9 | 1 | 1.5 | ? | ? |
C. mediterranea Steuer, 1940 | 1.5 | 1 | 2.9 | 2 | 1.2 | P | 0.3 | 10 | 1 | 1 | 5 | 3/6 | 7 | 0/0/1/3 | ? | 8 | 1.3 | 5 | 1.3 | + | 1.5 | 1.8 | 0.6 | 1 | 1 | – |
C. norvegica Boeck, 1865 | 2.5 | 1.2 | 1.1 | 2.2 | 2.7 | A | 0.6 | 10 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | 1.3 | 2 | 1.4 | 1.8 | ? | ? |
C. oblivia Monchenko, 1981 | 2.3 | 1 | 1.9 | 1.6 | 1.3 | P | 0.3 | 10 | 1 | 1 | 5 | 3/6 | 6 | 0/0/1/3 | 3 | 8 | 1.4 | 5 | 1.4 | – | 1.3 | 1.5 | 0.7 | 1 | ? | ? |
C. pacifica Smirnov, 1935 | 2.4 | 1.1 | 3 | 1.4 | 1.5 | P | 0.3 | 13 | 1 | 1 | 5 | 3/6 | ? | ? | 3 | ? | ? | ? | ? | ? | 1 | 2 | 1.2 | 1.8 | ? | ? |
C. parapsammophila Monchenko, 1981 | 1.3 | 0.8 | 2.4 | 3 | 2.1 | P | 0.6 | 10 | 2 | 1 | 4 | 3/6 | 7 | 0/0/1/3 | 3 | 8 | 1.8 | 4 | 1.3 | – | 1 | 1.7 | 0.8 | 1.4 | 0 | + |
C. phoenicia Lindberg, 1953 | 3 | 1 | 1.5 | 1.6 | 1.6 | P | 0.3 | 10 | 1 | 1 | 4 | 3/5 | ? | ? | ? | ? | ? | 5 | 1.4 | ? | 2 | 2 | 1.2 | 1.2 | ? | ? |
C. pontica Monchenko, 1977 | 3.7 | 1.3 | 0.9 | 1.6 | 1.5 | A | 0.7 | 10 | 1 | 0 | 4 | 3/5 | 7 | 0/0/1/3 | 2 | 8 | 1.6 | 5 | 1.6 | – | 1.8 | 1.8 | 1 | 1.2 | ? | ? |
C. psammophila Steuer, 1940 | 1 | 0.7 | 4.7 | 1.8 | 1.8 | P | 0.3 | 10 | 0 | 1 | 5 | ? | 6 | 0/0/1/3 | 3 | 8 | ? | 4 | 1.5 | – | 1 | 1.7 | 0.8 | 1.8 | 0 | ? |
C. pygmaea Sars, 1918 | 5.5 | 2 | 0.8 | 1.8 | 2 | A | 0.8 | 10 | 1 | 1 | 4 | ? | ? | ? | 3 | 7 | ? | ? | ? | ? | 1.1 | 1.5 | 1.2 | 0.9 | ? | ? |
C. rotundipes Herbst, 1952 | 2.5 | 1.2 | 1 | 1.4 | 1.4 | A | 0.6 | 10 | 0 | 1 | 4 | 3/5 | 6 | 0/1/2 | 3 | 7 | 1.1 | 5 | 1.1 | – | 1.4 | 1.3 | 0.9 | 1 | 1 | + |
C. schneideri Scott T., 1903 | 1.6 | 0.9 | ? | ? | ? | P | 0.5 | 12 | 1 | 1 | 3 | 3/6 | ? | ? | 3 | 8 | ? | ? | ? | ? | 1 | 1.5 | 0.9 | 1.5 | ? | ? |
C. sinaitica (Por, 1979) | 2.9 | 1.4 | 1.3 | 1.8 | 1.7 | A | 0.5 | 10 | 1 | 1 | 5 | 3/5 | 6 | 1/1/3 | 2 | 7 | 1.3 | 5 | 1.6 | – | 1.3 | 1.7 | 1.2 | 1.4 | 2 | – |
C. smirnovi Herbst, 1982 | 1.3 | 0.9 | ? | ? | ? | P | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | 1.1 | 1.4 | 1.5 | 4.1 | 1 | – |
C. soror Karanovic, 2008 | 1.5 | 0.7 | 3.4 | 1.8 | 1.4 | P | 0.2 | 11 | 1 | 1 | 5 | 3/4 | 6 | 0/0/1/3 | 3 | 8 | ? | 5 | 1.7 | – | 1.9 | 2.9 | 0.3 | 0.6 | ? | ? |
C. steueri Früchtl, 1923 | 2.2 | 1.2 | 2 | 1.6 | 1.9 | A | 0.5 | 10 | 0(1) | 0 | 5 | 3/6 | 6(7) | 0/0/1/3 | 3 | 7 | 1.5 | 5 | 1.5 | – | 1.5 | 1.6 | 1.1 | 1.1 | 1 | + |
C. tuberculata Herbst, 1962 | 3.2 | 1.8 | 0.8 | 1.8 | 2.1 | A | 0.2 | 10 | 1 | 1 | 5 | 3/6 | 6 | 0.1.3 | 3 | ? | 1.5 | 5 | ? | – | 1.4 | 2.5 | 1.6 | 1.3 | ? | ? |
C. unisetosa Karanovic, 2008 | 2 | 1 | 2.2 | 1.9 | 1.9 | P | 0.3 | 10 | 1(2) | 1 | 4 | 3/4 | 6 | 0/0/0/3 | 3 | 8 | 1.5 | 5 | 1.5 | – | 1.4 | 2 | 1 | 1.7 | ? | ? |
C. vachoni Nicholls, 1939 | 2 | 1.1 | 0.7 | 1.1 | ? | P | 0.2 | 10 | 0 | 1 | 3 | 2/6 | 7 | 0/0/0/4 | 3 | 8 | 1.5 | 5 | 1.6 | – | 1.1 | 1.7 | 0.6 | 1.2 | ? | ? |
C. wido sp. nov. | 2.3 | 1.4 | 0.6 | 1.2 | 0.6 | A | 0.3 | 10 | 0 | 1 | 4 | 3/6 | 6 | 0/0/1/3 | 2 | 7 | 1.1 | 5 | 1.3 | – | 1.9 | 1.7 | 0.5 | 0.7 | 2 | – |
C. yutimaete Lotufo, 1994 | 2.7 | 1.5 | 1.5 | 1.9 | 1.7 | A | 0.3 | 10 | 2 | 1 | 5 | 3/5 | 7 | 0/0/1/4 | 2 | 8 | 1.4 | 5 | 1.5 | + | 1.3 | 1.8 | 1.1 | 1.5 | ? | ? |
Cyclopina koreana is easily distinguishable from most congeners by its slender and widely spaced caudal rami, as well as by only four setae on the third exopodal segment of fourth leg. Only C. adelphae Karanovic, 2008 has somewhat similar caudal rami, but this Australian species has a completely different armature formula of the antennula, antenna, and swimming legs, as well as a more bulbous copulatory duct and slenderer fifth leg. Four setae on the third exopodal segment of fourth leg is a character so far reported only for three other congeners (see Table
Including C. curtijeju, there are currently only seven species of Cyclopina with caudal rami that are less than 1.5 × as long as wide (Table
Cyclopina wido has a completely unique swimming legs armature formula in the genus. It shares its two-segmented endopod of the first leg with only four congeners: C. arenosa Lotufo, 1994 from Brazil; C. pontica Monchenko, 1977 from the Black Sea; C. sinaitica (Por, 1979) from the Red Sea; and C. yutimaete Lotufo, 1994 from Brazil. All these species, however, have two setae on the second endopodal segment of second to fourth legs and differ from C. wido in many additional morphological characters (see
Several problems illustrated above should make it obvious that the genus Cyclopina is in need of revision. Unfortunately, as already mentioned by several researchers (
This work was supported by a grant from the National Institute of Biological Resources (NIBR), funded by the ministry of Environment (MOE) of the Republic of Korea (NIBR202004101). I am very grateful to Prof Gi-Sik Min (Inha University, Incheon) for a continuous support through the research project ‘Discovery of Korean Indigenous Species’. I would also like to thank Prof Ivana Karanovic and Ms Pham Thi Minh Huyen (both from Hanyang University, Seoul) for their generosity in sharing research facilities and providing administrative help respectively. The scanning electron microscope was made available through the courtesy of Prof. Jin Hyun Jun, and I also want to thank Mr. Junho Kim for the technical help provided (both from Eulji University, Seoul).