Hydrobiologia 379: 159–168, 1998.© 1998Kluwer Academic Publishers. Printed in Belgium. 159

Redescription and taxonomic status ofSinodiaptomus valkanovi, a commonlimnoplanktonic calanoid copepod in Japan, with comparison to theclosely relatedS. sarsi

Hiroshi Ueda1 & Susumu Ohtsuka21 Nakajima Marine Biological Station, Ehime University, Nakajima-cho, Onsen-gun, Ehime 791-4502, Japan2 Fisheries Laboratory, Hiroshima University, Minato-machi 5-8-1, Takehara, Hiroshima 725-0024, JapanCorresponding author: H. Ueda (E-mail: hueda@dpc.ehime-u.ac.jp)

Received 3 February 1998; in revised form 4 June 1998; accepted 21 June 1998

Key words:Calanoid copepod, taxonomy,Sinodiaptomus valkanovi, S. sarsi, limnoplankton, Japan

Abstract

The limnoplanktonic calanoid copepodSinodiaptomus valkanovi(Diaptomidae: Diaptominae) is redescribed indetail from Japan, where it commonly occurs in ponds and reservoirs especially around the Seto Inland Sea. Thespecies has been referred to as a subspecies ofS. sarsioutside Japan due to lack of subsequent morphologicalcomparisons.Sinodiaptomus valkanoviis easily distinguishable fromS. sarsiby having longer antennules in bothsexes, a short projection on the right antennule segment 15 of the male, and a thumb-like posterodistal basalprojection of the male left leg 5. These characters do not show significant variation, indicating differentiation atthe species level.S. valkanoviis restricted to Japan, in contrast to the wide-range ofS. sarsiin Asian waters. TheBulgarian population, from which the species was originally described, and the North American population, whichwas formerly recorded asS. sarsi, are considered to have been introduced from Japan with aquatic plants such aswater lilies.

Introduction

Sinodiaptomus valkanoviKiefer, 1938 is the domi-nant calanoid copepod in ponds and reservoirs aroundthe Seto Inland Sea (Ito, 1965; Mizuno, 1984). Thisspecies was originally described as a subspecies ofS.sarsi Rylov, 1923, from a botanical garden in Sofia,Bulgaria. Ito (oral presentation at the annual meet-ing of the Japanese Society of Limnology in 1953;afterwards Mizuno, 1984, 1991) examined Japanese,Chinese and MongolianSinodiaptomusspecimens andelucidated the morphological differences amongS.chaffanjoni(Richard, 1897),S. sarsiandS. valkanovi.As far as we know, he was the first investigator toelevateS. valkanovito the species level. Since thenS. valkanovihas been reported as a species in Japan(Mizuno, 1964, 1984, 1991; Ito, 1965; Tomikawa,1971; Ito & Miura, 1973). However, it is still re-ferred to as a subspecies ofS. sarsiin foreign countries(Kiefer, 1978; Dussart & Defaye, 1983; Reddy, 1994)

though Löffler (1961) once suggested that it is anindependent species. Recently Reddy (1994) consid-ered that the two taxa,S. sarsi and S. valkanovi,are conspecific and expressed doubts even about thesubspecies status of the Bulgarian population. We sup-pose that this confusion in taxonomic status is dueto the lack of detailed description ofS. valkanovi,despite its abundance in Japan. In this paper we re-describeS. valkanovifrom Japan in detail along withS. sarsifor purposes of comparison, and discuss thezoogeography of both species.

Materials and methods

Sinodiaptomus valkanoviwas collected from a smallpond 1 km east of Hiroshima University, located inHigashi-hiroshima City, Hiroshima, by surface towsof a plankton net of 0.1-mm mesh on 16 December1996. Specimens ofS. sarsiexamined were from a

hy98.tex; 6/10/1998; 19:05; p.1

Article: hy98 GSB: 7011901 Pips nr. 184146 (hydrkap:bio2fam) v.1.1

160

farming pond in Nakagusuku Village, Okinawa Island,the main island of the Ryukyus, on 20 April and 31August 1985, and from reservoirs on Ishigaki Island,one of the southernmost islands of the Ryukyus, on27 August 1991. The sampling methods for these Ok-inawan specimens and a map of the localities werepresented by Ueda & Ishida (1997). All specimenswere preserved in 2% buffered formaldehyde solutionuntil examination. Dissection and measurements weremade in lactophenol and drawings were made withthe aid of a camera lucida. For detailed observations,we used a differential interference microscope (NikonNT-16). Terminology for appendages is adopted fromHuys & Boxshall (1991). The following undissectedspecimens are deposited in the collections of theUnited States National Museum of Natural History:20 females (USNM 277663) and 20 males (USNM277664) ofS. valkanovifrom Hiroshima, and 20 fe-males (USNM 277665) and 20 males (USNM 277666)of S. sarsifrom Nakagusuku Village on 31 August1985.

Description

Sinodiaptomus valkanoviKiefer, 1938(Figures 1–3)

Synonyms

Diaptomus chaffanjoni(non Richard, 1897): Kikuchi,1928: 71, Figures 21–28; Light, 1939: 473.Diaptomus (Sinodiaptomus) sarsi(non Rylov, 1923):Wilson, 1959: 776, Figure 29.59.Sinodiaptomus sarsi valkanovi: Kiefer, 1938: 265–270, Figures 1–5; Kiefer, 1978: 157–158, plate70 (part); Reddy, 1994: 201, Figures 1068–1081;Borutzky et al., 1991: 420–423, Figure 187 (part).Sinodiaptomus valkanovi: Löffler, 1961: 385; Mizuno,1964: 93–94, plate 33, Figures 1a–f; Ito, 1965: 471,Figure 476; Ito & Miura, 1973: 437, Figure 20–50.8;Mizuno, 1984: 490–491, Figure 264; Mizuno, 1991:9, Figure 11.Sinodiaptomus monrovia: Strelezkaya, 1986: 83–84,Figure 9.I (NEW SYNONYMY).

Female: Body (Figures 1A and 1B) length 2.13–2.22 mm (n = 4). Pedigers 4 and 5 (Figures 1A–D)incompletely fused with suture visible laterally; mid-dorsal projection (Figures 1B–G) usually pointed anddirected posteriorly but variable in size and shape.

Pediger 5 (Figures 1C, 1D and 1H), left wing bentupward and broader than right one in dorsal view. Me-dial spine on right wing smaller than lateral one andthose on left wing. Genital compound somite (Fig-ure H) asymmetrical with dilated left proximal part,spine on which larger than right one; lateral surfacewith curved ridge (arrowed in Figure 1B). Caudal ra-mus (Figure 1I) 1.8–1.9 times longer than wide; lateralhairs grouped in 3 bundles; caudal setae normal andsymmetrical.

Antennule (Figures 1A, 1B and 1J) 25-segmented,when relaxed extending beyond apical caudal setae by3 segments, caudal ramus by 6 segments, or distal endof prosome by at least 9 segments; setal formula as fol-lows: 1+aesthetasc(ae), 3+ae, 1+ae, 1, 1+ae, 1, 1+ae,1+spine, 2+ae, 1, 1, 1+spine+ae, 1, 1+ae, 1, 1+ae, 1, 1,1+ae, 1, 1, 1+1, 1+1, 1+1, 5+ae (1 seta near aesthetascvery fine). Relative lengths of antennular setae as inFigure 1J.

Antenna (Figure 2A) coxa and basis incompletelyfused on posterior surface; coxa with 1 seta apicallyand group of several spinules medially; basis with 2setae. Exopod 8-segmented (ancestral segments 2–4fused); setal formula: 1, 3, 1, 1, 1, 1, 1, 3. Endopod in-distinctly 3-segmented (in some specimens segments2 and 3 fused medially); segments 1 and 3 each withgroup of spinules; setal formula: 2, 9, 7.

Mandible (Figure 2B) basis with 4 setae. Exopod4-segmented (ancestral segments 4–5 fused); setal for-mula: 1, 1, 1, 3. Endopod segment 1 with 4 setae;segment 2 with 8 setae and rows of spinules.

Maxillule (Figure 2C) praecoxal arthrite with 14setae of which 9 marginal, 4 posterior and 1 anterior;coxa with 4 setae on endite and 9 setae on epipodite;basis with 4, 4 and 1 setae on first, second endites andexite, respectively; exopod with 6 setae; endopod 2-segmented, each with 4 setae.

Maxilla (Figure 2D) with 5, 3, 3, 3, 3, 1, 1, 1,1, 2 setae on first and second praecoxal endites, firstand second coxal endites, basal endite, and first (fusedwith basis) to fourth (terminal) endopod segments,respectively; praecoxal endites with row of spinules;praecoxal endites each with row spinules.

Maxilliped (Figure 2E) praecoxa and coxa incom-pletely fused; praecoxal endite with 1 seta; first to thirdcoxal endites with 2, 3, 4 setae, respectively; basiswith 2 longitudinal rows of spinules and 3 setae alonganterior margin. Endopod 6-segmented; setal formula:2, 3, 2, 2, 1+1, 4.

hy98.tex; 6/10/1998; 19:05; p.2

161

Figure 1. Sinodiaptomus valkanovi. Female: A. Habitus, dorsal; B. Habitus, left lateral; C. Pedigers 4–5, right lateral; D. Pedigers 4–5, leftlateral; E–G. Variations of middorsal projection; H. Pediger 5 and genital compound somite, dorsal; I. Caudal rami, dorsal; J. Left antennule,ventral.

hy98.tex; 6/10/1998; 19:05; p.3

162

Figure 2. Sinodiaptomus valkanovi. Female: A. Left antenna, anterior; B. Right mandible, posterior; C. Right maxillule, posterior; D. Rightmaxilla, medial; E. Left maxilliped, medial; F. Left leg 1, anterior; G. Left leg 2, anterior; H. Right leg 3, anterior; I. Right leg 4, posterior; J.Leg 5, posterior.

hy98.tex; 6/10/1998; 19:05; p.4

163

Figure 3. Sinodiaptomus valkanovi. Male: A. Habitus, dorsal; B. Habitus, lateral; C. Pediger 5 and genital somite; D. Anal somite and caudalrami, dorsal; E. Right antennule, ventral; F. Modified seta on right antennule segment 17; G. Leg 5, posterior.

hy98.tex; 6/10/1998; 19:05; p.5

164

Seta and spine formula of legs 1 to 4 (Figures 2F–I) as follows:

coxa basis exopod endopod

1 2 3 1 2 3

Leg 1 0–1 0–0 I–1; 0–1; I,I,4 0–1; 1,2,3

Leg 2 0–1 0–0 I–1; I–1; I,I,5 0–1; 0–2; 2,2,3

Leg 3 0–1 0–0 I–1; I–1; I,I,5 0–1; 0–2; 2,2,3

Leg 4 0–1 1–0 I–1; I–1; I,I,5 0–1; 0–2; 2,2,3

Leg 2 (Figure 2G) endopod segment 2 without trace ofSchmeil’s organ.

Leg 5 (Figure 2J) coxa with chitinous projectionon distolateral corner much smaller than endopod; ex-opod segment 2 with spine near base of segment 3and spinule row on lateral and medial margins of endclaw; exopod segment 3 small, with 2 apical spines,longer spine smooth or with marginal spinules; en-dopod 2-segmented or 1-segmented with incompletesegmentation.

Male: Body (Figures 3A and 3B) length 1.97–2.11 mm (n= 5); pedigers 4 and 5 completely sep-arated. Pediger 5 (Figure 3C) slightly asymmetrical,with minute medial spine and large lateral spine oneach side. Genital somite with minute spine on eachside. Caudal ramus (Figure 3D) 2.0 times longer thanwide, naked on lateral margin; right ramus with lon-gitudinal ridge, extending to middle of anal somite;terminal setae being more parallel than female.

Left antennule (Figure 3B) 25-segmented, extend-ing beyond distal end of prosome by 8 segments orcaudal ramus by 3 segments; ornamentation as infemale. Right antennule (Figure 3E) 22-segmented,geniculated between segments 18 and 19; segments10–11 and 13–16 with spiniform projections anteri-orly; projections of segments 13–16 decreasing insize distally; antepenultimate segment with comb-like process anterodistally; setal formula: 1+ae, 3+ae,1+ae, 1, 1+ae, 1, 1+ae, 1+spine, 2+ae, 1, 1,1+spine+ae, 1, 2+ae, 2+ae, 2+ae, 1+spine, 2, 2, 2+2,1+1, 5+ae (1 seta very fine); proximal seta on segment16 and seta on segment 17 (Figure 3F) modified at tip.Other cephalic appendages and legs 1–4 as in female.

Leg 5 (Figure 3G), right and left coxae coalesced,each with standing spine on caudal surface. Right leg5, basis with hyaline process on medial margin andthumb-like posterodistal process (arrowed), extendingbeyond proximal margin of exopod segment 2; exo-pod segment 2 about 1.5 times as long as wide, with

spine at distal 1/4 of lateral margin and round chiti-nous process between the spine and distal end; lateralspine of segment 2 as long as one fifth or one fourth ofsegment width; endopod 1- or 2-segmented. Left leg 5,basis with small lateral spine and small medial processnear distal margin. Exopod 2-segmented, with hairsmedially on segment 1 and proximal part of segment 2;thumb-like exopod segment 2 with curved, terminallyhaired stout spine on anterior surface and transverse,membranous folds on distomedial surface.

Remarks:In the subfamily Diaptominae, the cephalicappendages except the antennule have scarcely beenused in distinguishing species and genera, and thenumber of detailed descriptions is still limited. How-ever, these appendages are variable among the generaof the subfamily. Regarding the antenna, for exam-ple, the present species differs fromScolodiaptomuscorderoi (Wright, 1936) described by Reid (1987) byhaving fewer setae on the endopod [the latter has 5, 12,13(14?) setae on the segments 1–3, respectively] andfrom Neodiaptomus satanasBrehm, 1952 describedby Reddy & Das (1981) by segmentation of the exo-pod [in the latter the ancestral segments 1–2 and 3–4are fused respectively]. Although the significance ofthese differences is presently unknown due to limitedinformation, the cephalic appendages seem to havetaxonomic value, especially in phylogenetic studies.

Sinodiaptomus sarsi(Rylov, 1923)(Figure 4)

Synonyms

Diaptomus chaffanjoni(non Richard, 1897): Sars,1903: 17–19, plate 2, Figures 1a–g.Diaptomus chaffanjonivar.sarsi: Rylov, 1923: 71–73,plate 2, Figures 13–18.Diaptomus sarsi: Kiefer, 1928: 104–106, Figures 16–19.Sinodiaptomus sarsi: Kiefer, 1938: Figures 6–9;Kikuchi, 1940: 291–292, Figure 4; Mashiko, 1951:149–151, Figures 6a–d; Shen, 1956: 5–6, plate 1,Figures 1–4; Löffler, 1961: 383–385, Figures 18–19; Smagowicz, 1976: 97, Figures 21–26; Shen &Song, 1979: 121–122, Figure 61; Chang & Kim, 1986:53–54, plate 3, Figures 6–8, plate 4, Figures 1–2;Borutzky et al., 1991: 420–423, Figure 187 (part);Dussart & Defaye, 1995: 140–142, Figure L40; Ueda& Ishida, 1997: 50–52, Figure 7.Sinodiaptomus sarsi sarsi: Kiefer, 1978: 157–158,

hy98.tex; 6/10/1998; 19:05; p.6

165

Figure 4. Sinodiaptomus sarsifrom Nakagusuku Village. Female: A. Habitus, dorsal; B. Habitus, lateral; C. Pediger 5 and genital compoundsomite, dorsal; D. Left antennule segments 10–12; E. Left leg 5, posterior. Male: F. Habitus, dorsal; G. Habitus, lateral; H. Right antennulesegments 9–17; I. Leg 5, posterior.

hy98.tex; 6/10/1998; 19:05; p.7

166

plate 70 (part); Reddy, 1994: 198, Figures 1065–1067,1082–1091.

Female: Body (Figures 4A and 4B) length 2.04–2.12 mm (n= 3) on 20 April and 1.62–1.89 mm (n= 6)on 31 August 1985 from Okinawa Island. Genitalcompound somite (Figure 4C) with weak dilation onleft lateral surface and less asymmetrical thanS. valka-novi. Caudal ramus 1.4–1.5 times longer than wide.Antennule extending usually to tip of apical caudal se-tae, or beyond caudal ramus by 2 segments or distalend of prosome by 7 segments; segment 11 (Fig-ure 4D) with 1 or 2 setae (one specimen with 1 setaon one antennule and 2 setae on the other). Leg 5(Figure 4E) coxa with distolateral projection nearly aslarge as endopod. Other characters as inS. valkanovi.

Male: Body (Figures 4F and 4G) length 1.94–2.06 mm(n = 3) on 20 April and 1.49–1.79 mm (n = 4) on 31August 1985 from Okinawa Island; 1.54–1.64 mm(n = 3) from Ishigaki Island. Caudal ramus 1.8 timeslonger than wide. Left antennule extending beyonddistal end of prosome by 6 segments and to distal mar-gin of anal somite or middle of caudal ramus. Rightantennule segment 15 (Figure 4H) with longer projec-tion than that of segment 14. Right leg 5 (Figure 4I)basis with wide-based triangular distal process (ar-rowed), end of which not reaching to exopod segment2; exopod segment 2 about 1.3 times as long as wide,with lateral spine as long as 1/3 of the segment width,inserted at distal 1/3 of lateral margin, and withoutprocess between spine and distal end. Other charactersas inS. valkanovi.

Remarks:Ueda & Ishida (1997) erroneously describedthe exopod of the left leg 5 of the male as 3-segmented,mistaking the narrow part of the terminal thumb-likeregion for a segment. Chang & Kim (1986) reportedthat Sinodiaptomus sarsifrom Korean waters lackedspinules on the lateral margin of the end claw of thefemale leg 5.

Discussion

Comparison and synonymy

In Kiefer’s (1938) original description,Sinodiaptomussarsi valkanoviwas distinguished from the nomino-typical subspecies mainly by the following charactersof the male: the shape of the distal process of the basis

of the right leg 5, the size of the lateral spine of theexopod segment 2 of the right leg 5, and the relativelengths of the spiniform projections on the right anten-nule segments 10–16. These characters of the Japanesespecimens agree well with those of the Bulgarian spec-imens and show no significant variation in the presentand previous descriptions from Japan (Kikuchi, 1928;Ito, 1965; Ito & Miura, 1973; Mizuno, 1984). Theseindicate that Bulgarian and Japanese populations be-long to the same species, which is independent ofS.sarsi.

Regarding the differences in the female, Kiefer(1938) noted the fusion of the pedigers 4 and 5, spineson the thoracic wings and those on the genital somite.However, the segmentation between the pedigers 4and 5 of the nominal subspecies illustrated by himmay be incorrectly described, becauseS. sarsi fe-males subsequently described from China (Mashiko,1951; Shen & Song, 1979; Reddy, 1994) and Iran(Löffler, 1961) have the last two pedigers fused asin the Japanese specimens.Sinodiaptomus valkanovifemales may be distinguishable by having more asym-metrical medial spines on the lateral wings and on thegenital somite thanS. sarsi, but the difference betweenthe two species is subtle. The shape of the wings,which was referred to as a distinguishing character byKiefer (1978), also does not clearly separate these twospecies, since its appearance varies depending on theangle of observation. Instead of these characters, therelative length of the antennule is most useful as a dis-tinguishing character in both sexes, i.e.S. valkanovihas much longer antennules thanS. sarsi. Althoughthe length of the antennule ofS. valkanoviwas men-tioned in Kiefer’s original description, it has neverbeen noticed as a distinctive character. As far as ourspecimens, the female ofS. valkanoviis also easilydistinguished by the relatively small projection on theleg 5 coxa, though Reddy’s (1994, Figure 1084)S.sarsi specimen from China has the small projection.Sinodiaptomus valkanovidiffers fromS. sarsiby hav-ing more asymmetrical genital compound somite ofthe female and longer caudal rami of the both sexesas well.

Kikuchi’s (1928) Diaptomus chaffanjonifromJapan was subsequently reidentified asSinodiaptomusvalkanovi by Ito (after Mizuno, 1984);S. chaffan-joni differs from bothS. sarsiand S. valkanovibyhaving small lateral wings of the pediger 5 in fe-male, a long lateral spine on the right leg 5 exopod2 in male, and so on (Kiefer, 1928; Reddy, 1994).Kikuchi’s (1928) illustration shows the characteristics

hy98.tex; 6/10/1998; 19:05; p.8

167

of S. valkanovisuch as the long antennule of bothsexes and the short projection on the segment 15 of theright antennule of the male. Wilson’s (1959)Diapto-mus sarsifrom Monrovia, California is also identifiedherein asS. valkanovibased on the projections on theright antennule segments 13–16 of the male and thethumb-like process on the basis of the right leg 5 of themale.Sinodiaptomus monrovia, which was created byStrelezkaya (1986) for Wilson’sD. sarsi, is therefore ajunior synonym ofS. valkanovi. Borutzky et al. (1991)have already noted thatS. monroviais synonymouswith the Bulgarian ‘S. sarsi’.

Zoogeography

Sinodiaptomus valkanoviis commonly distributed insmall ponds and reservoirs from the central part ofHonshu (Mainland Japan) to northern Kyushu (Ito,1965; Mizuno, 1984). It is the only representativeof the genus in temperate waters of Japan (Ueda &Ishida, 1997). Borutzky et al. (1991) suggested thatTomikawa’s (1971) figures ofS. valkanovi, which wascollected from a pond on Awaji Island in the InlandSea of Japan, may have been mixed with another con-gener. However, they seem to have been misled byTomikawa’s figures, which were somewhat inaccu-rate (e.g., 4-segmented female urosome). In contrastto the wide distribution ofS. sarsiacross Asia fromsouthern Japan (Ueda & Ishida, 1997) to Iran (Löffler,1961; Smagowicz, 1976),S. valkanoviis apparentlyendemic to Japan, because there have been no reliablerecords from other regions except for the followingtwo isolated localities, to which the populations couldhave been introduced. One is the type locality, a watertank in a botanical garden in Sofia, Bulgaria (Kiefer,1938). Kiefer (1978) noted that the water tank was nolonger in existence at the time that he wrote, and left aquestion about from where and how this Asian specieswas introduced to Bulgaria. Another record outsideJapan is a pond in California, USA (Light, 1939, asDiaptomus chaffanjoni; Wilson, 1959, asS. sarsi).This Californian population, which also did not persist(Reid & Pinto-Coelho, 1994), was considered to havearrived with aquatic plants from Asia, since it wasfound in a pond culturing exotic water lilies (Light,1939; Reid & Pinto-Coelho, 1994). Now the Japanesepopulation can be identified as the origin of these iso-lated populations because of the distribution range ofthe species noted above. As the previous authors sug-gested, they were introduced probably associated withtransport of aquatic plants such as water lilies, which

are common in temperate ponds in Japan. Accordingto Reid & Pinto-Coelho’s (1994) review of interconti-nental introductions of free-living copepods, Kiefer’s(1938) finding of the Bulgarian population seems theoldest one among known introductions of freshwatercopepods by human activities.

Mizuno & Mori (1969, 1970) recordedSinodiap-tomus valkanovi(as misspelled nameS. volcanoi) andHeliodiaptomus kikuchiiKiefer, 1932 from BorapetLake, Thailand. However, Bricker et al. (1978) subse-quently surveyed a planktonic fauna of the same lakeand did not find these species but two different diap-tomid copepods,Neodiaptomus botuliferKiefer, 1974and an unidentified species. They considered that thedifference from Mizuno & Mori’s study was probablydue to taxonomic uncertainty. We reexamined Mizuno& Mori’s plankton sample in question, which was pro-vided by Dr T. Mizuno, and found that it contains twounknown diaptomid species belonging toNeodiapto-mus (not botulifer) and Allodiaptomusinstead ofS.valkanoviandH. kikuchii.

Mizuno et al. (1979) once reportedS. valkanovi(as misspelled nameS. volkanoni) from a fish pondin Kimhae City, Korea. However, our reexaminationof their samples revealed that no diaptomid speciesoccurred in the sample from which they recordedS.valkanovi. Instead, we foundSinodiaptomusspeciesin another sample collected from a lotus pond in thesame city. This form is probably identical to Chang &Kim’s (1986) one, which is somewhat different fromthe Okinawan or ChineseS. sarsias noted above. Al-though there is a possibility that the Korean populationbelongs to a new taxa, we presently identify it asS.sarsi because of the shape of the distal process onthe basis of the male right leg 5 and so on. At anyrate,S. valkanovipreviously recorded from Thailandand Korea seems to be incorrect identification. De-tailed descriptions of the unknown diaptomid speciesfrom Thailand and of KoreanS. sarsiwill be presentedelsewhere.

Acknowledgements

We are grateful to Dr J. W. Reid, Smithsonian In-stitution, for reviewing the manuscript and kindlyproviding us many useful references and suggestions.We also thank Dr S. Shokita, the University of theRyukyus, for providing us the samples from Okinawa.Special thanks are due to Dr T. Mizuno, who kindly

hy98.tex; 6/10/1998; 19:05; p.9

168

gave most of his plankton collections to one of us(HU).

References

Borutzky, E. V., L. A. Stepanova & M. S. Kos, 1991. Key toCalanoida of freshwaters of the USSR. Academy of Sciences ofthe USSR, Zoological Institute, St. Petersburg ‘Nauka’, 503 pp.(In Russian with English abstract)

Bricker, K. S., L. Wongrat & J. H. Gannon, 1978. Composition anddistribution of crustacean plankton in twelve inland water bodiesof Thailand. Kasetsart Univ. Fish. Res. Bull. 10: 1–14.

Chang, C. Y. & H. S. Kim, 1986. The freshwater Calanoida(Crustacea: Copepoda) of Korea. Korean J. Syst. Zool. 2: 49–60.

Dussart, B. H. & D. Defaye, 1983. Répertoire mondial des CrustacésCopépodes des Eaux Intérieures I. – Calanoïdes. Centre Nationalde la Recherche Scientifique, Paris, 224 pp.

Dussart, B. H. & D. Defaye, 1995. Copepoda. Introduction tothe Copepoda. Guides to the Identification of the Microinverte-brates of the Continental Waters of the World 7, SPB AcademicPublishing, The Hague, 277 pp.

Huys, R. & G. A. Boxshall, 1991. Copepod evolution. The RaySociety, London, 468 pp.

Ito, T., 1965.Sinodiaptomus valkanoviKiefer. In: New IllustratedEncyclopedia of the Fauna of Japan, II. Hokuryu-kan, Tokyo:471. (In Japanese)

Ito, T. & Y. Miura, 1973. Subclass Copepoda. In M. Ueno (ed.),Tamiji Kawamura’s Freshwater Biology of Japan. Hokuryu-kan,Tokyo: 434–454. (In Japanese)

Kiefer, F., 1928. Beiträge zur Copepodenkunde (IX). Zool. Anz. 76:99–110.

Kiefer, F., 1938. Eine neue Diaptomidenform (Crust. Cop.) ausBulgarien. Zool. Anz. 123: 265–270.

Kiefer, F., 1978. Das Zooplankton der Binnengewässer. Freileben-den Copepoda. Die Binnengewässer 26: 1–343.

Kikuchi, K., 1928. Freshwater Calanoida of middle and south-western Japan. Mem. Coll. Sci. Kyoto Imper. Univ. Ser. B 4:65–79, Plates 18–22.

Kikuchi, K., 1940. Copepod fauna of Manchurian inland waters.In T. Kawamura (ed.), Report of the Limonological Survey ofKwantung and Manchukuo. Igyoku-do: 281–300. (In Japanese)

Light, S. F., 1939. New American subgenera ofDiaptomusWest-wood (Copepoda, Calanoida). Trans. am. Microsc. Soc. 58:473–484.

Löffler, H., 1961. Beiträge zur Kenntnis der Iranischen Bin-nengewässer. II. Regional-limnologische Studie mit besonderBerücksichtigung der Crustaceenfauna. Int. Rev. ges. Hydrobiol.46: 309–406.

Mashiko, K., 1951. Studies of the fresh-water plankton of CentralChina, II. Sci. Rep. Kanazawa Univ. 1: 137–154.

Mizuno, T., 1964. Illustrations of the freshwater plankton of Japan.Hoikusha Publishing, Osaka, 351 pp. (In Japanese)

Mizuno, T., 1984. Freshwater Calanoida in Japan. In: C. J. Shen& T. Mizuno (eds), Chinese/Japanese Freshwater Copepoda.Tatara-shobo, Yonago: 475–499. (In Japanese)

Mizuno, T., 1991. Order Calanoida. In T. Mizuno & E. Takahashi(eds), An Illustrated Guide to Freshwater Zooplankton in Japan.Tokai University Press, Tokyo: 2–16. (In Japanese)

Mizuno, T. & S. Mori, 1969. Preliminary hydrobiological researchof some southeast Asian inland waters. Mem. Osaka KyoikuUniv. 18, Ser. 3: 119–165. (In Japanese with English abstract)

Mizuno, T. & S. Mori, 1970. Preliminary hydrobiological survey ofsome southeast Asian inland waters. Biol. J. Linn. Soc. 2: 77–117.

Mizuno, T., S. W. Kang & K. S. Cho, 1979: Summary of the re-search on inland-water plankton in Korea. In: Overseas ScientificResearch on ‘History of environmental changes in Korea’ of theMinistry of Education, Japan, 1978’s interim report: 63–88. (InJapanese)

Reddy, Y. R. & P. K. Das, 1981. A redescription ofNeodiapto-mus stanasBrehm, 1952 (Copepoda, Calanoida) with criticalcomments on its present taxonomic status. Crustaceana 41: 1–9.

Reddy, Y. R., 1994. Copepoda: Calanoida: Diaptomidae. Guidesto the Identification of the Microinvertebrates of the ContinentalWaters of the World 5, SPB Academic Publishing, The Hague,221 pp.

Reid, J. W., 1987.Scolodiaptomus, a new genus proposed forDiaptomus(sensu lato)corderoiWright, and description ofNo-todiaptomus brandorffi, new species (Copepoda: Calanoida),from Brazil. J. Crustacean Biol. 7: 364–379.

Reid, J. W. & R. M. Pinto-Coelho, 1994. An Afro-Asian continentalcopepod,Mesocyclops ogunnus, found in Brazil; with a new keyto the species ofMesocyclopsin South America and a reviewof intercontinental introductions of copepods. Limnologica 24:259–368.

Rylov, W. M., 1923. On the Eucopepoda Fauna of Manchuria. Ann.Mus. Zool. Petrogr. d. Russ. Akad. d. Wiss. 24: 52–95, Plates1–3. (In Russian)

Sars, G. O., 1903. Fresh-water Entomostraca from China andSumatra. Arch. Math. Naturvid. 25: 3–40, Plates 1–4.

Shen, C. J., 1956. On a collection of Copepoda from ChinghaiProvince and Inner Mongolia. Acta Zool. Sinica 8: 1–16, Plates1–6. (In Chinese with English abstract)

Shen, C. J. & D. X. Song, 1979. Calanoida. In: Fauna Sinica, Crus-tacea, Freshwater Copepoda. Science Press, Peking: 53–163. (InChinese)

Smagowicz, K., 1976. On the zooplankton of Lake Zeribar, westernIran. Acta Hydrobiol. 18: 89–100.

Strelezkaya, E. Y., 1986. Toward a revision of the freshwatercalanoid crustacean fauna of Beringia. In: Biogeography of theBeringian sector of the Subarctic. Published by the Institute ofBiological Problems of the North, Academy of Sciences of theUSSR, Vladivostok: 64–99. (In Russian)

Tomikawa, T., 1971. Ecological studies on a freshwater copepod,Sinodiaptomus volkanoniKiefer. 1. Morphology, reproductionand feeding behavior. Bull. Plankton Soc. Japan 18: 1–11. (InJapanese with English abstract)

Ueda, H. & T. Ishida, 1997. Species composition and description oflimnoplanktonic copepods from Okinawa. Plankton Biol. Ecol.44: 41–54.

Wilson, M. S., 1959. Calanoida. In W. T. Edmondson, H. B. Ward &G. C. Whipple (eds), Fresh-water Biology, John Wiley & Sons,New York/London: 738–794.

hy98.tex; 6/10/1998; 19:05; p.10