New records and redescriptions of American species of Mesocyclops and of Diacyclops bernardi (Petkovski, 1986) (Copepoda: Cyclopoida)

19 Pages·1993·1.4 MB·English

by  Reid, Janet W

Bijdragentot de Dierkunde, 63 (3) 173-191 (1993)
SPBAcademie Publishingbv, The Hague
New records and redescriptions of American species of Mesocyclops and
of Diacyclops bernardi (Petkovski, 1986) (Copepoda: Cyclopoida)
JanetW. Reid
Department of InvertebrateZoology, NHB-163,NationalMuseumofNaturalHistory, Smithsonian
Institution, Washington, DC20560, U.S.A.
Keywords: Taxonomy, Copepoda, Cyclopoida, Mesocyclops, newrecords, U.S.A.
Abstract Introduction
Recent collections in the south central U.S.A. have included Taxonomieunderstanding ofthetropico-temperate
three neotropicaland oneprobablyintroduced speciesthatare eyelopoid eopepod genus Mesocyclops has greatly
presentlyassignedtothe cyclopoidcopepodgenusMesocyclops. improved during the past decade. Recognition of
Mesocyclopslongisetusvar.curvatusDussart, 1987,isreported
theimportance of formerlyignored subtlemorpho-
from Louisiana, U.S.A., and Panama;published records of
Mesocyclops longisetus (Thiébaud, 1914) sensu lato in the logical, usually meristiccharactersbyKiefer(1981),
southern U.S.A. arereviewed. Mesocyclops reidae Petkovski, Van de Velde(1984a, b), and Dussart &Fernando
1986,is reported from Mississippi, U.S.A., and Honduras. (1988) has ledto more accurate characterizationof
Mesocyclops ruttneri Kiefer, 1981,is redescribed from type manypaleotropical species. Itis desirableto supply
specimens collected in Austria, and newly reported from
similarly detailed descriptions for the American
Louisiana, Mississippi, China,Thailand,and Viet Nam. This
species is considered tohave been introduced from Asia into species.
Austriaandthe U.S.A.Mesocyclopsbernardi Petkovski, 1986, New records of copepods from non-lacustrine
newlyrecorded fromLouisiana andMexico,istransferred tothe wetlandsinthesouthernU.S.A. haveextended the
genus Diacyclops. known geographical rangesof manyspecies. Neo-
tropical species appear to comprise a significant
and previously littleappreciated componentofthe
Résumé
regional copepod fauna(Reid, 1992). Several neo-
tropicalspecies appearedincollectionsofcyclopoid
Dans des prélèvements récemment réalisés au sud des parties copepods that were madefromLouisianaand Mis-
centrales des U.S.A. ont été découvertes trois espèces néo-
sissippi, U.S.A. by Gerald G. Martenand sent to
tropicalesetuneespèceprobablementintroduite de Copépodes
Cyclopoïdes actuellement considérés comme appartenant au mefor determination(Marten, 1989; 1990a, b). In
genre Mesocyclops.Mesocyclopslongisetusvar.curvatus Dus- additionto thecommon NorthAmerican Mesocy-
sart, 1987,est mentionné deLouisiane (U.S.A.)etde Panamá; clopseda(xS.A.Forbes, 1891),therewerefourspe-
sont passés en revue les mentions publiées de Mesocyclops cies that are presently assigned tothe same genus:
longisetus (Thiébaud, 1914) sensulato dans les zones méri-
Mesocyclops bernardi Petkovski, 1986, Mesocy-
dionales des U.S.A.Mesocyclopsreidae Petkovski, 1986,est
connudu Mississippi (U.S.A.) et du Honduras. Mesocyclops clopslongisetus var. curvatusDussart, 1987, Meso-
ruttneri Kiefer, 1981, est redécrit sur des exemplaires-type cyclops reidaePetkovski, 1986, and Mesocyclops
d’Autriche,etnouvellement mentionné deLouisiane,du Missis- ruttneriKiefer, 1981. Examinationof materialin
sippi,deChine,Thaïlande,etVietNam; onconsidère cettees- the C.D. Marsh Collection of Copepoda in the
pèce comme ayant été introduite d’Asie en Autriche et aux
NationalMuseum of Natural History led to new
U.S.A. Mesocyclops bernardi Petkovski, 1986— nouvellement
mentionné pourla Louisiane etle Mexique— est transféré au recordsofM.longisetus var. curvatusandM. reidae
genre Diacyclops. from Panama and Honduras, respectively. The
174 /.W. Reid - New records ofAmerican Mesocyclops andDiacyclops bernardi
present articledescribesaspects ofthemorphology Discussion. — TheNewOrleans specimens are con-
and reviews the known distribution ofM. longise- gruentin the proportions of the caudalrami, the
tus var. curvatus, M. reidae, and M. ruttneri. The formoftheantennularmembrane,andin theleg 4
transfer ofM. bernardito the genusDiacyclops is endopodite 3, with M. longisetus var. curvatus
proposed. An additionalnew record for D. ber- Dussart, 1987. The lateral arms of the seminal
nardiis given fromMexico. receptacles ofmostspecimens examinedare strong-
For taxonomie examination, specimens were ly recurved posteriorly. In afew specimens, these
treated according to the methods of Reid et al. arms are littlerecurved posteriorly, thereforecloser
(1989). Terminology, particularly for the seminal to M. longisetus (Thiébaud, 1914) sensu restricto
receptacle and the antennuleis taken fromFiers& Dussart, 1987.
Vande Velde(1984) and Vande Velde(1984a, b). The record from New Orleans was previously
Descriptions of the morphology of species of reported by Marten (1989, 1990b). The earliest
Mesocyclops are basedon theredescription ofthe record of M. longisetus sensu lato in the U.S.A.
genotype, M. leuckarti (Claus, 1857) by Van de may be that of Herrick (1887), whose extensive
Velde(1984a). Specimens are depositedeitherinthe figures of “Cyclops simplex” from southern
collectionsofG.G. Marten,NewOrleansMosquito Alabama clearly show a species of Mesocyclops
ControlBoard, or intheU.S. NationalMuseumof withthecaudalramushairedonthemedialsurface,
NaturalHistory, SmithsonianInstitution(USNM). theantennularhyaline membranewithasingle deep
notch, and the leg 4 coupler with two triangular
projections. However, theillustrationofthe semi-
nal receptacle (Herrick, 1887: plate VII, fig. la)
Taxonomicsection
shows themedianthirdoftheanteriormargin con-
cave andthelateralarms tapering, not roundedas
Family Cyclopidae Burmeister, 1834
the receptacle of M. longisetus. Reddell (1965,
Subfamily Cyclopinae Dana, 1853, char, emend. repeated in Reddell& Mitchell, 1969) reported M.
Kiefer, 1927
longisetus from Felton Cave, Sutton County,
Genus Mesocyclops G.O. Sars, 1914
Texas. Thespecies was also recorded fromFlorida
byDussart&Fernando(1986), butadditionallocal-
ity data for their record are unavailable (C.H.
Mesocyclops longisetus var. curvatus Dussart, 1987 Fernando, inlitt., 1990). It seems thatM. longise-
tus sensu lato, whichis distributedthrough Mexico
Synonymy. - Mesocyclops longisetus var. curvatus Dussart, and Central and South America as far south as
1987: 150, 156, figs.3, 4, 7,8; Reid, 1990: 181,table I. Patagonia and possibly Tierra del Fuego, occurs
Mesocyclops longisetus (Thiébaud, 1914);Marten, 1989:232, widely althoughsporadically inthesouthernU.S.A.
233,235,table 1;1990b:681-687, tables 1,4,5, 7,8; Reddell, The distributionof M. longisetus var. curvatus is
1965: 157;?Reddell & Mitchell, 1969:7; ?Dussart & Fernando,
uncertain.
1986: 291, 292.
Cyclops simplexPoggenpol,1874;?Herrick, 1887: 14, 17-18, Therecords for Panamafromthe Marsh Collec-
pl. VII fig. 1. tion are previously unpublished.
Material. - USNM252008,699,samplesMl and M6, Lake
Mesocyclops reidaePetkovski, 1986
Catherine marshes, 24 July 1991,afterintroduction from cul-
tures originally collected from Joe Brown Lagoon, New (Figs. 1, 2)
Orleans, Louisiana, coll. G.G. Marten. One 9,dissected on
slide,and 2 9 9,ethanol-preserved,sample105,NewOrleans, Synonymy. - Mesocyclopsreidae Petkovski, 1986:47,61-66,
Louisiana, 1988,G.G.Marten collection. USNM AccessionNo. 71-73, 78,Abb. 11-22; 1988:40;Sket, 1988:79,table 1;Reid,
120079 (Marsh Collection),several 9 9 on slides, Panama, 1990: 181,table 1.
C.D. Marsh prep. nos. 3826,3827,3842, 3843,and 3943. Un- Mesocyclopsellipticus (nonKiefer, 1936a);Yeatman, 1977:
mounted specimenspreservedin 70% ethanol. 5-7, figs. 1-16; Smith & Fernando, 1978: 2015, 2016, 2019,
Bijdragen tot deDierkunde, 63 (3) - 1993 175
Fig. 1.Mesocyclopsreidae Petkovski,1986,dissected￿ fromMississippi,USNM252009:a,pediger5andgenitalsegment,rightlateral;
b,pediger5 and genitalsegment, ventral;c,leftleg5,lateral-oblique,setaenotcompletelyindicated;d,copulatoryporeandpore-canal,
lateral-oblique;e, analsomiteand caudalrami,dorsal;f,anal somiteand caudalrami, ventral;g,antennule articles 16and 17;h,anten-
naarticle 1,caudal side;i,antennaarticle 1, frontalside;j,labrum,spines indicated only ononeside;k, maxilliped.Scale appliesto
Figs. 1a-conly.
176 J.W. Reid New records of American Mesocyclops andDiacyclops bernardi
2020,figs.21-24,tables 1,2; 1980: 11, 18,20,fig.9A-D,table margin(indicated by arrow) short, noothersurface
2; Reddell, 1981: 81; Pesce, 1985: 296, 311, 316-318, figs. ornamentation.
63-65. Labrum (Fig. lj) with 2 rows of long spines on
each side of medianline. Maxillule as in M. leu-
Material.- USNM252009,1 9,dissected onslide,and 109 9,
ricefield, Cleveland, Mississippi, September 1991, coll. G.G. ckarti, i.e. lacking spines onsurfaceofpalp. Maxil-
Marten. USNM Accession No. 120079 (Marsh Collection), 2 la as inM. leuckarti, lacking spines on surfaceof
9 9 on slides,C.D. Marsh prep. nos.4288, 4296,Honduras. coxa (article 2), distal half of ventral surface of
coxa rugose. Maxilliped (Fig. Ik) article 2 (basis)
Description offemale.- Range oflengths of Mis- with3transverse rowsofsmallspines alongposter-
sissippi specimens 0.80-1.02mm(median = 0.90 ior border;middleseta of article4 (endopodite 2)
mm, n = 10). Resembling description ofPetkovski short in comparison to corresponding seta of con-
(1986) of typepopulation fromSanAndrés Island, geners.
Colombia, in most details. Legs 1-4 as inM. leuckartiexcept in following
Supplementary observations:Posterolateralmar- details. Leg 1 (Fig. 2a) with medialseta ofbasipo-
gin of pediger 4 finely serrate (Fig. la). Pediger 5 diteshort, stout, with spines at base; coupler with
(Figs, la, b) with small lateral spines disposed in 2 rounded marginal expansions. Leg 2 (Fig. 2b),
3 diagonal rows. Leg 5 (Figs, la-c) with median medial expansion of basipodite haired, coupler
spine inserted at distal }A ofarticle 2. Genital seg- with2 largeblunttriangularexpansions. Leg 3(Fig.
ment (Figs, la, b) lacking ornamentation except 2c), medialexpansion ofbasipodite haired, expan-
fewpapillae bearing sensillanearposterior margin. sions of coupler large, broadly triangular, acute.
Pore-canal of seminal receptacle (Figs, lb, d) Leg 4(Figs. 2d, e),posterodistal marginofcoxopo-
short, directed dorsally, in semilateral view seen dite with short row of small spines; basipodite
to be recurved anteriorly. Copulatory pore with naked medially; coupler with 2 medially directed
slightly sclerotized anterior margin. Anal somite slenderacuminatespiniform processes; andmostof
(Figs, le, f), posterodorsal margin lacking spines; lateralmarginofmedialterminalspine ofendopo-
posteroventral margin with small spines, mediad ditearticle 3 finely spinulate.
spines larger. Caudalramus (Figs, le, f)similar to
description of Petkovski (1986: 62, Abb. 13) in Discussion. - Principal characters such as the
lacking spines near baseof lateralseta, but having characteristic marginal protrusions of the swim-
2tiny spines anterior to base of lateralmost termi- ming leg couplers, theshort stout medial spine of
nal caudal seta in both Mississippi and Honduras the leg 1 basipodite, andthe relativelengths ofthe
specimens. Medialmost terminal caudal seta less caudal setaeagreesoclosely withtheample descrip-
than twice length of lateralmost terminal caudal tion ofPetkovski (1986)thatIhavenohesitationin
seta. assigning thespecimens fromMississippi andHon-
Antennulearticle 1,smallspines disposed inrow duras to thistaxon. Petkovski (1986: 64, Abb. 18)
as in M. leuckarti; articles 2-17 lacking surface didnotobserve spinules onthelateralmarginofthe
spines; appendages of antennule exactly as in leg 4endopodite 3 medioterminalspine, but these
M. leuckarti (Van de Velde, 1984a: 14, fig. 5A). are very fine and difficult to see in some of the
Antennulehyaline membranes(Fig. lg),membrane specimens athand.
of article 16 narrow, margin finely serrate rather Both the Hondurasand Mississippi records are
than entire as observed by Petkovski (1986: 62, previously unpublished. Petkovski (1986) syn-
Abb. 14); membraneofarticle 17broader, slightly onymized several records ofM. ellipticus with his
morecoarsely serrate, extending distally from seta newspecies M.reidae.Withthediscovery ofM. rei-
near midlength ofarticle. dae in Mississippi the known range of this species
Antenna (Figs, lh, i) with basic spine pattern is extended significantly northwardfrom Central
for genus, spine rows, especially row on anterior America, Mexico, and theAntilles.
Bijdragen tot deDierkunde, 63 (3) - 1993 177
Fig. 2.Mesocyclopsreidae Petkovski, 1986,dissected￿ fromMississippi,USNM 252009: a,leftleg1 and coupler,anterior, most of
rami notindicated;b, leftleg2coxa-basipoditeand coupler,anterior;c, leftleg3 coxa-basipoditeand coupler,anterior;d, rightleg
4 and coupler,posterior,most oframi notindicated;e, rightleg4endopoditearticle 3,posterior, setulesof setaenotindicated.
Mesocyclops ruttneriKiefer, 1981 Material. - ParatypesfromtheF.Kiefer Collection,Staatliches
(Figs. 3-5) Museum fiir Naturkunde Karlsruhe: Mikropráparat 11101, 2
9 9 Abd. + P5, prep. Kiefer,30September 1980;Mikroprá-
parat 11102, 1 9 A1-P4, prep. Kiefer, 30 September 1980;
Synonymy.- MesocyclopsruttneriKiefer, 1981: 151,156, 178— Mikropráparat 11285,several 9 9 Al, 4A2, prep. Kiefer, 11
180, 186, 187, Abb. 1 (54, 55), 14; Marten, 1990b: 681-688, November 1982;morethan 20adults, Glas No. 470; 1 9 from
tables 1-8. Glas No. 470,dissected on slide, prep. Reid; all from Warm-
Mesocyclops sp. (leuckarti-group);Marten, 1989: 232-235, wasserim Glashaus,Lunz, Österreich, 4December 1926,coll.
table 1; 1990a: 160. Klie? (question markaccordingtoKiefer's label).
NonM. pehpeiensis(Hu, 1943); Dussart& Fernando, 1985:
246; 1988: 249;Lim & Fernando, 1985: 73, 80, 83-85, figs. Additional, non-paratype material: USNM 90830, 24 çç,
57-59. ponds, Foochow, Fukien Province, China, April 1948, coll.
?MesocyclopsLeuckartipehpeiensisHu, 1943: 115,124-126, C.C.Tang.USNM250683,1 Ç,2o-er,8copepodids,Lumtak-
table II,fig.c. longCreek,KhaoYai National Park, 100kmnortheastofBang-
178 J.W. Reid New records ofAmericanMesocyclops andDiacyclops bernardi
Fig.3.MesocyclopsruttneriKiefer, 1981,paratype ￿ ￿ fromtheKieferCollection (a,d,e,fromGlas470;b,c, from Mikropräparat
11101;f,g,from Mikropräparat11102):a,habitus,dorsal;b,pediger5 andgenitalsegment, ventral;c,anal somite andcaudal rami,
dorsal;d,antennule,setaenotindicated;e, antennule article 17;f,antennaarticle1,caudalside;g,antennaarticle1,frontalside. Scale
appliestoFig.3a.
Bijdragen tot deDierkunde, 63 (3) - 1993 179
kok,Thailand,24January1989,coll. T.Ishida. USNM250565, to insertionoflateralseta, and 5 or6 larger spines
699,ricefield on ComptonFarm, nearNew Orleans, Loui- dorsal and lateral to base of lateralmost terminal
siana (afterexperimentalintroduction), 10August 1990,coll. caudalseta; medialsurfaceof ramus naked. Most
G.G. Marten. USNM 252010, 2 9 9, eachdissected onslide,
caudalsetae withfineuniformplumage, dorsalseta
Lagoon (canal) in Joe Brown Park, east New Orleans, Loui-
siana, July 1987, coll. G.G. Marten. USNM 252011, 1 9,8 naked.Proportions oflengths of caudal setae as in
crcr, 5 copepodids,sample No. 70, Lagoon (canal) in Joe Fig. 3a.
Brown Park,east NewOrleans,Louisiana, 10June 1988,coll. Antennule (Figs. 3a, d, e) when completely
G.G. Marten. USNM 252012, 1 9, dissected onslide, and 28 reflexedreaching slightly past posterior margin of
9 9,sample No. 105,Lagoon (canal),Joe Brown Park, east
pediger 2,setationlikethatofM. leuckarti; articles
New Orleans, Louisiana, 30 June 1988, coll. G.G. Marten.
USNM252013,23adultspecimens,culture,originallyfrom east 4,5, and7-13withrows of groupsofsmallspines,
New Orleans, Louisiana, 1989, coll. G.G. Marten. USNM withsome variation:article 5 with2 rowsof spines
252014,14 9 9 ,6 a-a,75 copepodids,samples209-210,from onmost specimens, withadditionalrow of3 spines
field trials,New Orleans, Louisiana, 1989,coll. G.G. Marten. on 1 antennuleoffemaleon Mikropràparat 11102.
USNM250564,1 9, ricefield,BebeFarm,near Jennings,Loui- Antennules of some specimens with few shallow
siana,9August1990,coll.G.G.Marten.USNM264729,49 9,
True Bach Lake,Hanoi, VietNam, 12 January 1993,coll. Vu round pits on dorsal surface of article 1. Hyaline
SinhNam.G.G.Marten collection: morethan20 9 9,Jennings membranes of antennulearticles 16 and 17 finely
ricefield, 26 July 1991; and more than 20 9 9, ricefield, serrate, membraneof article 17with deep notch.
Cleveland,Mississippi, 10August 1991.Undissected specimens Antenna(Figs. 3f, g) general structure including
ethanol-preserved.
setationlikethatofM. leuckarti; article1, inaddi-
tionto basic spine patternof genus(Van de Velde,
Description of female. —Length as given by Kiefer 1984a, b), caudal side with oblique row of tiny
(1981) for type population, 1.0-1.15 mm; lengths spines nearmedialmargin, single or doubleirregu-
of 10 unmountedparatype specimens, 1.0-1.28 lar transverse row of6-14 larger spines at level of
mm;ofspecimens fromFukien, China, 1.10-1.23 proximalmost medialseta,and2-4spines near dis-
mm (median - 1.16 mm, n = 10); of specimen tal margin.
from Thailand, 1.26 mm; of specimens from Labrum, mandible, maxillule, and maxilla as
Compton Farm, Louisiana(USNM 250565), 0.98— corresponding structures of M. leuckarti. Maxil-
1.19mm(median = 1.04mm,n = 6); ofspecimens liped (Fig. 4a) withrow of smallspines on article 1
from Viet Nam, 1.34-1.56mm (median = 1.41 and 2 groups of many small spines on article 2;
mm, n = 4). setules of most setae sparse.
Redescription of paratype specimens: Habitus Leg 1 (Fig. 4b), medialexpansion of basipodite
(Fig. 3a) slender; pediger 5 littleexpanded laterally, lacking seta, leg otherwise similar in setationand
lacking ornamentationon lateral and dorsal sur- ornamentationto leg 1 ofM. leuckarti. Legs 2and
faces except two hairs near dorsomedianline as 3 similar to those of M. leuckarti except lacking
presentin allcongeners.Genitalsegment (Figs. 3a, groupof tiny spines near proximolateral corner of
b), anteriorhalflittleexpanded, fewscatteredshal- posterior surface of coxopodite, present in M.
low circular pits on lateral and dorsal surface of leuckarti (location indicatedby arrow in Fig. 4c).
posterior half, surface including area posterior to Leg 4(Figs. 4d-h) similar tothat ofM. leuckarti,
leg 6 otherwise without ornamentation. Seminal except medialexpansion of basipodite naked and
receptacle (Fig. 3b) with anterior margin slightly coxopodite with 2 transverse rows of spines along
concave, lateralarms nearly horizontal, theirlater- posterodistal margin, these rows well separated in
al ends slightly recurved anteriorly; posterior mar- most specimens; 1 or 2 rows of small spines on
gins leading anteriorly from copulatory pore, more posterior surfaceofcoxopodite nearlateralmargin
orless fusednearporeindifferentspecimens before variously developed in different specimens, these
diverginglaterally;pore-canal long, curvedposteri- rows lacking in Louisianaspecimens (Figs. 4d, e,
orly. Caudal rami (Figs. 3a, c) about 3.2 times arrows). Marginal spiniform processes of leg 4
longer than broad, bearing 1 or2 tiny spines dorsal coupler (Figs. 4d, g, h) more or less triangular,
180 /.W. Reid - Newrecords ofAmericanMesocyclops andDiacyclops bernardi
Fig. 4. Mesocyclopsruttneri Kiefer, 1981,paratype ￿ ￿ from the Kiefer Collection (a, b, d from Glas 470; c, e, f, g, h from
Mikropräparat 1102;g,h from different specimens):a,maxilliped;b, leg 1 and coupler,anterior; c,leg2 coxa-basipodite,posterior;
d,leg4 and coupler,posterior;e,leg 4 coxa-basipodite,posterior; f,leg4endopoditearticle 3; g,h, leg4 couplers.
Bijdragen tot deDierkunde, 63 (3) - 1993 181
Fig. 5.MesocyclopsruttneriKiefer, 1981,a-c, dissected ￿ fromLouisiana,USNM 252012;d,e, paratype ￿ fromtheKiefer Collec-
tion,Glas 470: a,antennule, setaeomitted;b, antennaarticle 1, caudal side;c, antennaarticle 1, frontal side;d, habitus,dorsal; e,
pedigers5, 6 and succeedingurosomite. Scale appliestoFig.5d.
always with acute curved slender tip. Leg 5 (Fig. ably constant in the individuals and populations
3b), seta of article 1 shorterthan seta of article2, examined.Thevariationof antenna spine patterns
seta and spine of article 2 subequal in length. (Figs. 3f, g, 5b, c) betweendistantpopulations was
Theantennulespine patterns(Figs. 3d, 5a) varied no greater than the within-population variation.
somewhatinthenumberandarrangementofspines The shape of the spiniform processes of the leg 4
oneach article, butthegeneral patternwas remark- coupler (Figs. 4d, g, h) varied from bluntly trian-
182 J.W. Reid - Newrecords ofAmerican Mesocyclops andDiacyclops bernardi
guiar to very slender, usually similar to Fig. 4d. not indicated) andLim& Fernando(1985, Malay-
sia) forthecaudal sideof antenna article 1 of “M.
Description ofmale.— Lengths ofparatypes from
pehpeiensis” show alarge diffusegroupratherthan
the KieferCollectionGlas No. 470, 0.73-0.89mm
arow of spines atthelevel of theproximal medial
(median = 0.82mm, n = 10). Habitus (Fig. 5d) seta,and nospines nearthedistalmargin. Thetwo
slender. Antennulegeniculate, setationandaesthe-
groupsoftiny spines ataleveldistaltothe longitu-
tascs of articles 1-4 similar to that described for
dinalrow ofspines onthefrontalsideofthisarticle
male of M. leuckarti by Gurney (1933: 290, fig.
shown by Dussart & Fernando(1986) and Lim &
1865). Dorsal surface of antennulearticle 1 of all
Fernando(1985) are not present injM. ruttneri.
specimens examinedwithseveraltransverserowsof
Seminalreceptacles also differ:inM. ruttnerithe
roundpits. Mouthparts and legs 1-5 as infemale.
lateralarms are narrower andslightly recurved an-
Leg 6 (Fig. 5e) composed of smalltrapezoidal flap
teriorly atthe lateralends. The posterior margins,
bearing 1 stout ventral spine, 1 short medianseta,
leading fromthecopulatory pore,inM. ruttneriare
and 1long dorsalseta reaching posterior marginof
always directedanteriorly andusually conjoined to
succeeding somite.
someextent fromtheporebeforediverging lateral-
Discussion. - Specimens of Mesocyclops ruttneri ly ina sharp curve, while in allrepresentations of
were first collected in Austria in a greenhouse, “M. pehpeiensis” these margins curve laterally
whichhadbeen destroyedby thetimethattheorigi- directly fromthe pore.
nal description was published(Kiefer, 1981). Kiefer InM. ruttnerithere are always one or two small
(1981) speculated that the species must be Asian. spines on the caudalramus proximal to the inser-
Dussart & Fernando (1985, 1988) and Lim & tion ofthe lateralcaudal seta. Spines atthis loca-
Fernando (1985) described aspecies fromAustra- tion are shown by neither Dussart & Fernando
lia, Burma, Indonesia, Malaysia, and Sri Lanka (1988) nor Lim & Fernando(1985).
and identifiedit as M. pehpeiensis Hu, 1943, a Finally, Lim &Fernando(1985) show themedial
poorly known species originally described from expansion of theleg4basipodite as thickly haired.
China.They synonymized M.ruttneriwithM. peh- Hu's(1943)original description ofM. pehpeien-
peiensis onthebasisofsimilaritiesbetweenKiefer's sis provides few of the morphological detailsthat
description and theirmaterial, apparently without are today considerednecessary to distinguish spe-
comparing type material of M. ruttneri. These cies of the genus. Hu gave the lengths of female
authors'figures of variouspopulations assigned to specimens as 1.525-1.710mm. He reported the
M. pehpeiensis differamong themselvesin several caudalramus of M. pehpeiensis as 3.5-4.0(mean
respects, particularly intheantenna spine patterns 3.7)timeslonger thanbroad,thusslightly narrower
and theindicationsof hairsor lack thereofon the than in the populations ofM. ruttneriexamined.
medialextension of the leg 4basipodite. Whether Otherwise there is no discernible differencefrom
or not the populations fromthesemutually distant M. ruttneri. Subsequent descriptions of Asian
localitiesare allconspecific, thedescription ofeach Mesocyclops populations ascribedto M. pehpeien-
differs in several respects from M. ruttneri. sis by Tai & Chen (1979) and by Kim & Chang
In Sri Lankan "M. pehpeiensis" (Dussart & (1989) unfortunately have not provided sufficient
Fernando, 1988) thecaudal sideof antenna article detailto clarify the problem (Reid &Kay, 1992). In
1 is shownas having a groupof5 tiny spines more viewofthedemonstratedpresenceinAsiaof sever-
orless atthelevelofthemoreproximal medialseta, alpopulations thatdifferfromeachotherinaseries
in contrast to the single or double row of 6-14 ofmicrocharactersbutthatareallmoreorless con-
small spines near the corresponding location and gruentwith Hu's description, comparison of topo-
theadditional2-4 smallspines nearthedistal cau- type materialisessential for afinal determination
dal margin thatare always present and easy to see of the identity of his species with M. ruttneri, or
inM. ruttneri. with subsequently describedpopulations ofMeso-
Figures by Dussart & Fernando (1986, locality cyclops fromAsia.