Arch. Protistenkd. 148 (1997): 445-459© by Gustav Fischer Verlag

Morphology, Infraciliature, and Ecology of Halteriidsand Strombidiids (Ciliophora, Oligotrichea)from Coastal Brackish Water Basins

SABINE AGATHA1,2) and JEANNETTE CORNEllE RIEDEL-LORJE1)

1) Institut fur Frischwasser- und Abwasserbiologie, Hamburg, Germany2) Institut fur Hydrobiologie und Fischereiwissenschaft, Hamburg, Germany

ARCHIVFUR

PROTISTENKUNDE

Summary: The morphology of some brackish water oligotrichs was investigated using in vivo,Lugol fixed and protargol impregnated material. One new species is described, Strombidium tri­quetrum nov. spec.; Pelagohalteria cirrifera (KAHL, 1935) FOISSNER, SKOGSTAD & PRATI, 1988,Strombidium conicum (LOHMANN, 1908) WULFF, 1919, and S. vestitum (LEEGAARD, 1915) KAHL,1932 are redescribed. Additionally, two unnamed species belonging to the genera StrombidiumCLAPAREDE & LACHMANN, 1859 and Cyrtostrombidium LYNN & GILRON, 1993 are described. Eco­logical data concerning maximum abundances, abundances at different salinities and tempera­tures, as well as contents of food vacuoles are given. The genus Ciliospina LEEGAARD, 1915 andits single species, Ciliospina norvegica LEEGAARD, 1915, are regarded as nomina dubia.

Key Words: Pelagohalteria; Strombidium; Cyrtostrombidium; Ciliospina; Taxonomy; Infracilia­ture; Brackish water; Ecology.

Introduction

At present, about 200 species of aloricate oligotrichs areknown (MAEDA & CAREY 1985; MAEDA 1986). Theirdescriptions are either mainly based on live specimensor fixed material, and only about 65 species have beendescribed or redescribed applying modem techniques(CZAPIK 1976; MIRABDULLAEV 1985; DRAGESCO &DRAGESCO-KERNElS 1986; FOISSNER et al. 1988, 1991;LYNN & MONTAGNES 1988; LYNN et al. 1988, 1991;MONTAGNES & LYNN 1988; MONTAGNES et al. 1988,1990; KRAINER 1991, 1995; SNYDER & OHMAN 1991;ALEKPEROV & MAMAYEVA 1992; PETZ & FOISSNER1992; LYNN & GILRON 1993; MARTIN & MONTAGNES1993; PETZ 1994; MONTAGNES & TAYLOR 1994; PETZet al. 1995).The planktonic ciliates of brackish water basins in twopolders at the west coast of Schleswig-Holstein (NorthGermany) were studied. These basins adjacent to theWadden Sea are characterized by high turbidity andchanging salinities. During the investigation period, the

genus Strombidium CLAPAREDE & LACHMANN, 1859dominated the aloricate oligotrichs, followed by thegenera Rimostrombidium JANKOWSKI, 1978 and Strom­bidinopsis KENT, 1881. The taxonomy, morphology,and ecology of the species belonging to the orders Hal­teriida and Strombidiida are reported here.

Material and Methods

Samples were taken by bucket from December to Februarymonthly, in March and November fortnightly and duringthe remaining months weekly in the brackish water lagoonsof the Beltringharder and Dithmarscher Koog (Fig. I). Onesubsamplewas always preserved with Lugol's iodine solu­tion. The abundances of the planktonic ciliates were deter­mined by UTERMOHL inverted microscopy using 2.5 mlLugol fixed material (AGATHA et al. 1994). The biomasswas calculated on the basis of Lugol fixed specimensusingsimple geometrical bodies for volume estimations and

446 S. A GATHA & J. RIEDEL-LoRJI~

9' •DANEMAR~~

o

IIwum

54· 0S·

s· .\6'

Fig. 1. Sampling stations on west coast of Schleswig­Holstein (after NEHRING 1994). A. Beltringharder Koog.B. Speicherkoog Dithmarschen.

0.19 pg Jlm-3 as the ratio of carbon to volume (PUTI &STOECKER 1989) or 1 pg Jlm-3 as the ratio of wet weight tovolume. A species was designated as sufficiently constantif it occurred in more than 25% of the samples.For taxonomic studies, live specimens were observedunder a light microscope, preserved in Bonin's fluid, and

subsequently impregnated with protargol following SONG& WILBERT (1995) . It was prefered to combine old and lessaccurate descriptions with species investigated by moderntechniques instead of establi shing new species. The classi­fication used here is accordin g to PETZ & ForSSNER (1992).

Results

Class Oligotrichea BUTSCHLI, 1887Family Halteriidae CLAPAREDE & LACHMANN, 1858Genus Pelagohalteria FmssNER, SKOGSTAD & PRATT,1988Pelagohalteria cirrifera (KAHL, 1935) FmssNER,SKOGSTAD & PRATT, 1988

Halteria cirrifera KAHL, 1935 - Tierwelt Dt!. 30: p. 840Halteria grandinella var. cirrifera KARL, 1932 - TierweltDt!. 25: p. 505, Fig. 2 (p. 506)Pelagohalteria cirrifera (KAHL, 1935) ForSSNER, SKOG­STAD& PRATI, 1988 -J. Protozoo!. 35: p. 491

Improved diagnosis. In vivo 25- 34x22- 34 urn. Spher­ical to obovoid, anteriorly slightly conical , posteriorlyhemispherical. 14-16 anterior and 6-7 ventral poly­kinetids. 7 bristle complexes.Type specimens. Neotype as 1 slide of protargolimpregnated cells has been deposited in the collectionof microscope slides in the Zoologische Mu seum Ham­burg .Redescription (Fig. 2, Table I). Shape anteriorlyslightly constricted, posteriorly broadly rounded. Crosssection circular. Intermembranellar ridges betweenanterior membranelles. Bean-like macronucleus filledwith spherical to ellipsoidal nucleoli. Micronucleusadjacent to macronucleus, usually not stained with pro­targo!. Contractile vacuole on the left side. Cytoplasmhyaline, with some small green enclosures. Feeds onpennate diatoms (7x4 urn) . Movement slowly rotating,interrupted by jumps. Bristle complexes in grooves,connected by fibril s, cilia 16 urn long. Bristle complexinvariably consisting of 4 vertica l and 4 horizontal kine­tosomes.Anterior polykinetids consisting of 3 rows of kineto­somes, bases connected by sys tem of fibres . Ventralpolykinetids each composed of 2 row s of kinetosomes.Paroral membrane on right of oral cavity. Oral pri­mordium originates ventrally between first and lastbri stle complex.Occurrence and ecology. Pelagohalteria cirrifera wasfound only once in the plankton with an abundance of9600 ind.ll on August 1st 1991 in the mixo-oligohalinereservoir of the Beltringharder Koog (station BSP). Atthat time, salinity was 4 %0 and temperature was 22 °C.Volume of protargol impregnated specimens on average5411 11m3, calculation based on globular body shape.

Halteriids and Strombidiids from Coastal Brackish Water Basins 447

-----,..

I

Fi~s . 2a-d. Pelagohalteria cirri/erafrom life (a) and after protargol im­pregnation (b-d). a , b. Ventral views .c. Dorsal view . d . Divider . APk =ante­rior polyk inctids, CV =contractile vac­uole. la =macronucl eus. Mi =micro­nucleus. FV = food vacuole. pM =paroral membrane. SB = bristle co m­plex. B I =vertical part of brist le com­plex . B ~ = horizontal part of bristlecomplex. VPk = ventral polykinct ids,Scale bars 10 um.

Table 1. Biometrical characterization of Pelagohalteria cirri/era. M = median , Max = max imum, Min = minimum,n =numb er of individuals examined, S =standard devi ation, Sx=stand ard error of arithmetic mean , V =coefficient ofvariation in %, x=arithmetic mean. All data based on prot argol impregnated specimens. Measurements in 11m.

Character Min Max x M S Sx V n

Body, length 18 27 22 22 2.49 0.72 11.3 12Body, width 19 27 21.4 21 2.07 0.6 9.64 12Macronucleus, length 8 14 10.8 10 2.04 0.65 18.9 10Macronucleus, width 6 10 7.2 7 1.14 0.36 15.8 10Micronu cleus, diameter 3 3 3 3 0 0 0 4Distance between anterior polykinetids 2 2 2 2 0 0 0 7Distance from apex to beginning 8 17 11.75 11 3.37 1.91 28.68 8

of bristle complexesNo. anterior polykinetids 14 16 15.1 15 0.9 0.34 5.94 7No. ventral polykinetids 6 7 6.2 6 0.45 0.2 7.21 5No. bristle com plexes 7 7 7 7 0 0 0 7No. kinetosomes in vertical component of 4 4 4 4 0 0 0 5

bristle complex (SB I )

No. kinetosomes in horizontal component 4 4 4 4 0 0 0 6of bri stle complex (SB2)

Total no. kinetosomes in bristle complex 8 8 8 8 0 0 0 4

Cell volume in !Jm3 3770 10306 5411 5074 1753 506 32.4 12

448 S. A GATHA & J. RIEDEL-LoRJE

According to KAHL (1932) and LIEBMANN (1962), P.cirrifera is abundant throughout the year in stagnantwaters under ol igosaprobic co nditions. However, eco­logical investigations (AGATHA et aI. 1994 ) showed aeutrophication of the water reservoir in the Beltring­harder Koog. This corresponds with its reg istrationfrom eutrophic fish ponds, hypertrophic lakes and pol­luted brooks (FOISSNER et aI. 199 1).Discussion. The population described here is very simi ­lar in size, position of the contractile vacuole and struc­ture and number of bristle complexe s to Pelagohalteriacirrifera (KAHL, 1935) FOISSNER, SKOGSTAD & PRATT,1988; thu s it is identified with this species. The ratherspherical to obovoid body shape differs , however, fromthe de scriptions of KAHL (193 2) and LIEBMANN (1962).A closely related species is P. viridi s (FROMENTEL,1876) FOISSNER et aI., 1988 , which differs from P. cir­rifera mainly by its symbiotic green algae, less conspic­uous horizontal bristle rows, a slightly higher number ofbristle complexes and ventral polykinetids.

Family Str om bidii dae FAURE-FREMIET, 1970Ge nus Strombidium CLAI'AREDE & LACHMANN, 1859Strombidium conicum (LOHMANN, 1908) WULFF,1919

Laboea conica LOHMANN, 1908 - Wiss. Meeresunters .,Abt. Kiel1O: p. 299, T. 17, Figs. 18-20

Strombidium conicum (LOHMANN, 1908) WULFF, 1919 ­Wiss . Meeresunters ., Abt. Helgoland 13: p. 115Strombidium conicum non HOFKER (193 I) - Arch. Protis­tenk. 75: p. 392, Figs. 86, 87Laboea acumin ata LEEGAARD, 1915 - Nyu . Mag. Natur­vidensk. 53: p. 22, Figs. 12 a-cStrombidium acuminatum (LEEGAARD, 1915) KAHL, 1932 ­Tierwelt Dtl. 25: p. 502, Fig. 8 (p. 501)

M orphology and infraciliatu re (Fig s. 3, 4, Table 2). Invivo 50-72x33-58 urn. Body obconical. Posterior por­tion with faint stripes parallel to main body axis . Oralcavity extends to girdle kinety. Macronucleus broadlyellipsoidal , contains numerous nucleoli; micronucleusadjacent to macronucleu s. Contractile vacuole not recog­nized. Cytoplasm brownish. Specimens sometimes withsmall spherical enclosures (endosymbionts?) and clayparticles. These particles, found in the posterior portionof living and fixed specimens, were pre sumably ingestedto feed on the attached microorganism s like bacteria,small pennate diatoms and cyanophyceae (FENCIIEL1968). Feeds on coccal organisms from various taxa (1- 3urn in diameter), centric diatoms (6!Jm in diameter), pen­nate diatoms (36x8 urn). Swims slowly in spirals withmembranelles perpendicular, interrupted by dapping.When it meets an obstacle, it moves backwards.Environmental stress and age ing evoke a dis tension ofthe cell surface and thu s an enlargement of the cell s.

Table 2. Biometrical characterization of Strombidium conicum. M = median , Max = maximum , Min = minimum,n =number of individual s examined, S =standard deviation , Sj[ =standard error of arithmetic mean , V =coefficient ofvariation in %, x=arithmetic mean. *) =S. conicum, **) =S. acuminatum. All data based on protargol impregnated speci-mens, volume calculations based on Lugol fixed individuals. Measurements in 11m.

Character Min Max x M S Sj[ V n

Body, length 42 93 63.93 64 10.55 0.83 16.5 162Body, width 23 51 34.57 33 5.3 0.41 15.31 166Macronucleus, length 9 29 17.34 17 3.89 0.34 22.43 174Macronucleus, width 6 18 9.75 10 2.15 0.16 22.07 174Micronucleus, diameter I 6 2.35 2 1.11 0.23 47.37 23Distance between anterior polykinetids 2 4 2.49 2 0.54 0.05 21.88 135Ventral kinety, length 10 41 23.24 22 6.07 0.55 26. 13 121No. anterior polykinetids 15 26 18.85 18 2.56 0.3 13.58 75No. ventral polykinetids 10 15 12.61 13 1.14 0.11 9.04 114No. kinetosomes in girdle kinety 46 90 67.5 66 10 1.38 14.9 53No. dikinetids in ventral kinety 14 37 23.62 22 5.86 0.52 24.8 121

Cell volume in I1mh ) 1492 56460 18027 16403 8973 709 49.8 160Cell volume in 1lffi3**) 4298 52466 18277 17421 7365 486 40.3 230

Figs.3a-h. Strombidium conicum (c- h) and synonymy (a, b). a. Laboea conica from life (from LOHMANN 1908). b. L.acuminata after fixation (from LEEGAARD 1915). c. Ventral view from life (after KAHL 1932). d. Typi cal specimen fromlife. e. Ventral view of aged or stressed specimen from life. f . Extrusome of crushed cell from life. g, h. Ventral and dorsalview of same specimen after protargol impregnation. APk =anterior polykinetids, CS =distended cell surface, Ex =extru­some, FV =food vacuole , G =girdle kinety , Ma =macronucleus, Mi =micronucleus, pM =paroral membrane, SG =clayparticle, Vk = ventral kinety , VPk = ventral polykinetids. Scale bars 10 11m.

Halteriids and Strombidiids from Coastal Brackish Water Basins 449

Ex

G

fiA~I'¥:-~~---- SG

.~.:=:.:...::.,.:,.;'------ Ma

,Zl----CS

Mi

CS

e

~~-VPk

•d

f

c

I

a

9 h

450 S. A GATHA & J. RIEDEL-LoRJE

a b c _

Figs. 4a-c. Strombidium conicum after Lugol fixation. a. Unstressed specimen. b, c. Frontal and lateral view of aged orstressed specimens, corresponding to L. acuminata.

Posterior to the girdle kinety, stripes and polygonalplatelets become visible, which are arranged in rows(Fig. 4b, c). The specimens look like S. acuminatum,with the posterior end of the cell curved slightly to theleft. Sometimes in individuals of that morphotype, theintermembranellar spaces are covered with bacteria.Extrusomes rod-shaped, 13-20 urn long, not grouped,insert in oblique rows in a 4-6 urn wide zone anterior togirdle kinety, converge posteriorly. Extrusome girdleinterrupted ventrally. Girdle kinety composed of mono­kinetids, in shallow furrow. Ventral kinety does notextend to girdle kinety, consists of dikinetids, only ante­rior kineto some each bearing a 1-2 urn long cilium.15-26 large anterior polykinetids continuous with10-15 smaller ventral polykinetids. Paroral membranecomposed of 29-37 kineto somes. The oral primordiumdevelops apokinetally above the ventral kinety on alevel with the girdle kinety. Strombidium conicum pos­sesses no neoformation organelle during interphase. Inearly dividers, the oral primordium is comma-likedeveloping in a posteriad direction. Upon reaching theaboral third of the cell, it winds towards the dorsal side.In late dividers , the separated macronuclei move intoproter and opisthe.Occurrence and ecology. During the whole year,Strombidium conicum was found at all sample station s.However, only in the mixo-polyhaline basin of the Spei­cherkoog Dithmarschen and in Meldorf Harbour (sta­tions DIll and DH) it occurred constantly. Maximumabundance and biomass were 123600 ind.ll, 0.43 mg ell

and 2.25 mg/l wet weight recorded on April 15th 1992in the mixo-polyhaline basin of the Speicherkoog Dith­marschen (station DIll). When it was most abundant, S.conicum dominated the assemblage of the aloricate

,,

.-f-

-~--~

;.~

~

Fig. S. Abundances of S. conicum at different salinities[%0] and temperatures [0C] in the Speicherkoog Dith­marschen and the Beltringharder Koog.

oligotrichs. It was euryhaline with highest abundancesat salinities of 12-24%0 and temperatures of about4-12 °C (Fig. 5). Cell volume of Lugol fixed specimenson average 18027 urn", calculation based on obconicalbody shape with semiglobular top.The distribution of S. conicum is mainly restricted to theneritic zones of North and Baltic Sea, the Atlantic,Skagerrak and Mediterranean Sea (LOHMANN 1908;LEEGAARD 1915; WULFF 1919; BUSCH 1921; KAHL1932; GAARDER 1938; RASSOULZADEGAN 1977;SMETACEK 1981; LEPpANEN & BRUUN 1986; KJVJ 1986;NIELSEN & KJ0RBOE 1991). Neither in these regions norin our sampling area, the species developed distinctpeaks of abundances. LOHMANN (1908) found S. con­icum throughout the year with maximum densities of710 ind.ll in autumn and spring. The species wasrecorded by LEEGAARD (1915) in low numbers in Mayin the North Sea and the Atlantic and from February tillMarch in the Skagerrak. Especially in summer andautumn, S. conicum was found at the coast of Norwaywith 1000 ind.ll in July (GAARDER 1938). In theMediterranean Sea, S. conicum occurred with 3.5x106

ind.ll in August and S. acuminatum with 32000 ind.ll inFebruary (RASSOULZADEGAN 1977). However, a correctspecies identification in the above mentioned ecologicalinvestigations is doubtful because cell sizes were dis­tinctly larger and silver impregnation was not used.Discussion. LOHMANN (1908) described Laboea conicafrom Kiel Bight and the Baltic Sea, where he found thespecies throughout the year. His drawings show threespecimens with a spherical as well as a broadly ellip­soidal macronucleus (Fig. 3a). The first redescriptionby KAHL (1932) characterizes the species by the pres­ence of a ventral kinety, a yellowish cytoplasm and abroadly ellipsoidal macronucleus (Fig. 3c).Using protargol impregnation, MONTAGNES et al. (1988;Figs. 3 a, b) described another population with usually a

Halteriids and Strombidiids from Coastal Brackish Water Basins 451

spherical macronucleus and a ventral kinety consistingof monokinetids. Their anterior and ventral polykinetidzone show a distinct separation with the latter beginningslightly inside the former. These characteristics differfrom those of our population.Although KAHL (1932) doubted that S. acuminatum andS. conicum are conspecific, in vivo observations showedthat S. acuminatum is very similar to aged or stressedspecimens of S. conicum (Figs. 3b e, 4b, c). Thus, theyare considered synonymous. LEEGAARD (1915) inter­preted the reticulated cell surface in big specimens as aphenomenon of ageing, and BUSCH (1921) consideredthe distended cell surface to be pathological.

Strombidium triquetrum nov. spec.

Diagnosis. In vivo about 45-50x45-50 urn. Body out­line triangular. Macronucleus C-shaped, consists of oneto three nodules. Girdle kinety continuous, composed ofmonokinetids. 15-16 anterior and 17-19 ventralpolykinetids. Ventral polykinetid zone curves diago­nally across ventral side.Locus typicus. Plankton of Meldorf Harbour in theSpeicherkoog Dithmarschen (station DH, 54°5'35" N,8°57'8" E; west coast of Schleswig-Holstein).Derivatio nominis. The species name is derived fromthe triangular (triquetrus, lat. = triangular) body shape.Type specimens. Holotype and paratype as 1 slide eachof protargol impregnated cells have been deposited inthe collection of microscope slides of the ZoologischeMuseum Hamburg.Description (Fig. 6, Table 3). Dorsoventrally flat­tened, cross section thus elliptical. Peristomiallip pro­jects above apical end of cell. Macronuclear nodulescontain numerous roundish nucleoli. Micronucleusspherical to ellipsoidal, 3-6 urn in diameter (n = 2),rarely impregnated with protargol. Contractile vacuole

Table 3. Biometrica1characterization of Strombidium triquetrum nov. spec. M =median, Max =maximum, Min =mini-mum, n =number of individuals examined, S =standard deviation, Sj( =standard error of arithmetic mean, V =coefficientof variation in %, x=arithmetic mean. All data based on protargol impregnated specimens. Measurements in urn.

Character Min Max x M S Sj( V n

Body, length 38 44 41.6 42 2.41 0.76 5.8 10Body, width 41 50 46 47 3.27 1.03 7.1 10Macronucleus, length 11 22 15.7 14 5.69 3.28 36.3 3Macronucleus, width 6 8 6.75 6.5 0.96 0.48 14.2 4Distance between anterior polykinetids 3 6 3.6 3 0.97 0.31 26.84 10Ventral polykinetid zone, length 26 33 29 28 3.61 2.08 12.43 33No. anterior po1ykinetids 15 16 15.6 16 0.55 0.24 3.51 5No. ventral polykinetids 17 19 17.7 17.5 0.82 0.33 4.62 6No. kinetosomes in girdle kinety 108 152 131 132 17 6.92 12.9 6No. macronuclear nodules 1 3 1.4 1 0.84 0.27 60.23 10

Cell volume in /lm3 33446 57596 46331 46844 7194.7 2275 15.53 10

452 S. AG ATHA& J. RI EDEL-L o RJE

I

Figs. 6a-c. Stromb idium triquetrumfrom life (a) and after protargolimpregnation (b-e), a. Ventral view.b, c. Ventral and dorsal view of samespecimen. APk = anterior poly­kinetids , Ex =extrusome, FV =foodvacuole, G = girdle kinety, Ma =macronucleus , Mi = micronucleu s,PL = peristomial lip, pM = paroralmembrane, VPk = ventral poly­kinetids. Scale bar 10 urn,

- - Ex

a

pM - --'-:-----f

b

APk

_~- VPk

r--- GEx

c

not found. Cytoplasm hyaline, sometimes with redinclusions (endosymbionts?). Feeds on pennate (24x6urn) and centric diatoms (14 urn in diameter) , the cili­ate Myrionecta rubra, and dinoflagellates. Swims

slowly and swayingly. Extrusomes inserting in a 2-3um wide zone immediately anterior to girdle kinety, inresting state about 8 urn long. Girdle kinety parallelsposterior portion of ventral polykinetid zone, i.e.

extends obliquely toward s rig ht side. Ven tral kinetynot fo und.Anterior membranelles cirri -like , radially projecti ng.Ventral polykinetid zo ne co nt inuo us with anteriorpo lykine tids . Paroral memb rane on right of ora l cavity.Strombidium triquetrum pos ses ses no neoformationorganelle during interph ase. The oral primordiumdevelops posterior of the oral cavity. Du ring morpho­genesis, the oral primordium elongates to the dorsalside and finally surrounds the posterior ce ll portionalmost completely.Occurrence and ecology. Strombidium triquetrumoccurred in the mixo-polyhaline wa ter basin of the Bel­trin gh arder Koog (station Bli) and in Meldorf Harbour(station DH) in August 1992. O nly a few specimenswe re found . Cell volume of pro targol impregnatedspecimens on average 4633 1 urn", calculatio n based onha lf ellipsoidal body shape.Discussion. As concerns shape, size, movement andfragmentation of macronucleus, S. triquetrum is verysimilar to S. obliquum KAHL, 1932. However, KAHL(1932) clearly shows a di scontinuous, slightly spirallinggirdle kinety and extrusome girdle. Furthe rmore, theven tra l polykinetid zone is less prominent, being appar­ently composed of fewer membranelle s. Thus, we donot consider our population to be conspecific.The food vacuole contents show that S. triquetrum feedson Myrionecta rubra . However, it is unclear, whe ther thereddish inclusions in the cytoplasm are cleptoplastsderived from M. rubra or digestive products.

Strombidium vestitum (LEEGAARD, 1915) KAHL, 1932

Laboea vestita LEEGAARD, 1915 - NyU. Mag . Naturvi ­densk . 53: pp. 23-24, Figs. 14 a-f

Halteri ids and Strombidiids from Coastal Brackish Water Basins 453

Strombidium vestitum (LEEGAARD, 1915) KAHL, 1932 ­Tierwelt Dtl. 25: p. 503, Fig . 14 (p. 50 1)Laboea delicatissima LEEGAARD, 1915 - Nyu. Mag.Naturvidensk. 53: pp. 24-25 , Figs. 15 a-cStrombidium delicatissimum (LEEGAARD, 1915) KAHL,1932 - Tierwelt Dtl. 25: p. 503 , Fig. 15 (p. 50 1)

Improved diagnosis. In vivo 20-35xI5-30 um . Bodysha pe obovoid to obconical. One continuous girdlekinety in anterior third of cell and one ventral kinety.13-18 anterior and 5-8 ven tral polykinetids. Ventralpolykinetid zone distinctly separated fro m anteriorpolykinetid zo ne, which forms an almost closed circle.Type specimens. Neotype as I slide of protargolimpregnated cells has been deposited in the collecti onof microscope slides of the Zoologisch e Museum Ham­burg.Redescr iption (Fig. 7, Table 4). Longer than wi de an dslightly flattened, right buccal lip slightly projecting.Po sterior cell surface sometimes distended, ret iculationnot visible in vivo, in Lugol fixed specimens, however,indistinct polygonal platelets were sometimes observed.Macronucleus ellipsoidal, in mid-body, containsnumerous nucleoli . Micronucleus spherical to slightlyellipsoidal, anterior to or laterally adjacent to macro­nucleus. Contractile vacuole was not found . Cytoplasmhy aline, often co ntains numerous food vacuoles . Feedson centric diatoms (3--4 urn in diameter), coccal organ­ism s and flagellates. Extrusomes not grouped, insert indiagonal rows, converge posteriorly. Extrusome girdleparallels girdle kinety, 1-2 urn wide. Girdle kinety com­posed of dikinetids, only left kinetosome each withshort stubby cilium. Ventral kinety in sha llow groove,composed of dikinetids, not extending to girdle kinety,only anterior kinetosomes ciliated.

Table 4. Biometrical characterization of Strombidium vestitum . M = median, Max = maximum, Min = minimumn =number of individuals examined, S =standard deviation, S- =standard error of arithmetic mean V =coefficient ofvariation in %, x=arithmetic mean. All data based on protargol impregnated specimens, volume calculations based onLugol fixed individuals. Measurements in 11m.

Character Min Max x M S Sx V n

Body , length 18 36 25.6 24 4.33 0.53 16.91 66Body , width 14 27 18.6 18 2.4 0.3 12.94 66Macronucleus, length 6 17 9.7 9 1.92 0.24 19.77 62Macronucleus, width 4 10 6.9 7 1.33 0.17 19.28 62Micronucleus, diameter 1 3 2 2 0.5 0.17 25.0 9Ventral kinety, length 8 17 13 13 2.75 0.59 21.24 22No. anterior polykinetids 13 18 16.3 17 1.23 0.21 7.57 33No. ventral polykinetids 5 8 6.1 6 0.45 0.06 7.38 49No . dikinetids in girdle kinety 42 72 57.1 56 6.66 1.09 11.66 37No. dikinetids in ventral kinety 8 18 13.8 14 2.63 0.54 19.09 24

Cell volume in 11m3 1283 32256 6399 4856 4969 395 77.64 158

454 S. AGA THA & J. RI EDEL-L oRJE

a

I Ex

-------- cs

Figs. 7a-<l. Strombidium vestitum. a. Fixed (from LEEGAARD 1915). b. Lateral view from life. c, d. Infraciliature ofventral and dorsal side after protargol impregnation. APk =anter ior polykinetids, CS =distended cell surface, Ex =extru­some, FY =food vacuole, G =girdle kinety , Ma =macronucleus, Mi =micronucleus, Yk =ventral kinety, VPk =ventralpolykinetids. Scale bars 10 urn.

Ventral polykinetid zone commences distinctly insideof anterior polykinetid zone. Cytostome rather centrallylocated. Distance between anteri or polykinetids 1-2urn, Paroral membrane not found. Strombidium vest i­tum possesses no neoformation organelle during inter­phase. The oral primordium originates apokinetally leftof the ventral kinety. During morphogenesis, the oralprimordium elongates to the dorsal side and finally sur­round s the posterior cell portion almost completely.Simultaneously, the macronu cleus develops a replica­tion band and elongates.Occurrence and ecology. Strombidium vestitumreached highest abundan ces at salinities >17%0 (Fig. 8).Temperature seemed to be less important for its occur­rence. The presence and domin ance of S. vestitum were,however, correlated with the influx of Wadden Seawater. Maximum abundance and biomass were foundon April 22th 1992 in the mixo-polyhaline water basinof the Beltringharder Koog (station BI) with 60400ind.ll , 0.037 mg CII and 0.19 mgll wet weight. Strom­bidium vestitum and S. conicum dominated the assem­blage of aloricate oligotrichs in the mixo-pol yhalinelagoon of the Beltringharder Koog. Cell volume ofLugol fixed specimens on average 6399 ).lID3, calcula­tion based on conical body shape with semiglobular top.Strombidium vestitum has been recorded from the Euro­pean north polar sea, the North Sea, the Baltic Sea, andthe North Atlantic (LEEGAARD 1915; BUSCH 1921; DALE& DAHL 1987).

Fig. 8. Abundances of S. vestitum at different salinities[%0] and temperatures [0C] in the Speicherkoog Dith­marschen and the Beltringharder Koog.

HalteriidsandStrombidiidsfromCoastalBrackishWaterBasins 455

Discussion. Based on fixed material, LEEGAARD (1915)described two very similar species differing only insize, viz. Strombidium vestitum (LEEGAARD, 1915)KAHL, 1932 and S. delicatissimum (LEEGAARD, 1915)BUSCH, 1921; the latter is slightly smaller (22-30 x17-25 urn vs. 15-20x12-1 6 urn); BUSCH (1921) evenmentioned 9-13 urn. Thus, our population is more simi­lar to S. vestitum. However, we found also considerablysmaller specimens than these, sugges ting that S. deli­catissimum is a synonym of S. vestitum (Table 4) . Fixedspecimens from the North Atlantic, which resemble S.vestitum, show a reticul ation of the posterior cell sur­face (BUSCH 1921). Consequently, BUSCH (1921) con­sidered S. vestitum to be a synonym of S. reticulatum.However, the latter species is twice to three times larger.Therefore, we do not regard it as conspecific. Strombid­ium vestitum differs from S. sulcatum CLAPAREDE &LACHMANN, 1858 in a more anteriorly situated girdle, aless prominent protuberance and the absence of a con­tractile vacuole. It differs from S. tressum LYNN et al.,1988 by the absence of exceptionally long anteriorpolykinetids. Strombidium inclinatum MONTAGNES etal., 1990 is distinguished by the almost continuous ante­rior and ventral polykinetids, the equatorial girdlekinety, and the macronuclear shape.

Strombidium spec.

Description (Fig. 9, Table 5). This species is very likelya new one. However, we observed it only in protargolslides, which is insufficient for a good descriptionbecause, e.g. size and shape of the extrusomes cannotbe recognized with this technique.Protargol impregnated specimens obovoid to ellip­soidal, slightly indented above mid-body, 32--48x22-33urn, Collar distinctly projecting on right side.Cytostome eccentrically. Macronucleus broadly ellip­soidal, contains numerous globular to ellipsoidal nucle­oli. Micronucleus spherical, attached to macronucleus,2 urn in diameter (n = 1). Extrusomes not impregnatedwith protargol or lacking. Ellipt ical structures (3-11 x3-6 urn) with a small, nucleus-like structure (1 urn indiameter) predominantly in aboral portion beneath cellsurface (endosymbionts?). Feeds on coccal organismsof various taxa (3-6 urn across), pennate diatoms (26x3um) and, rarely, clay particles. Girdle kinety in mid­body, discontinuous on ventral side, slightly spirallingwith right end shifted posteriad, composed of about36-50 dikinetids (n = 2) having only anterior kineto­some ciliated. Ventral kinety in shallow groove, com­posed of dikinetids, only anterior kinetosomes bearshort (1- 2 urn) stubby cilium.Ventral polykinetid zone continuous with anteriorpolykinetids. Distance between anterior polykinetids1-2 urn. Paroral membrane on right of oral cavity.

456 S. AGATHA & J. RIEDEL-LoRJI';

Ma

+='--- -----=-- - Vk

a

APk------..

G

bFigs. 9a, b. Strombidium spec. a, b. Infraciliature of ventral and dorsal side of same specimen after protargol impregna­tion. APk =anterior polykinetids, CS =distended cell surface, G =girdle kinety, Ma =macronucleus, Mi =micronucleus,pM =paroral membrane, Vk =ventral kinety, VPk =ventral polykinetids. Scale bar 10 urn.

Strombidium spec. possesses no neoformation organelleduring the interphase.Occurrence and ecology. Strombidium spec. was onlyfound in protargol impregnated samples from the plank­ton of the mixo-oligohaline reservoir of the Beltring­harder Koog (station BSP). Cell volume of protargolimpregnated specimens on average 18296 urn", calcula­tion based on ellipsoidal body shape.

Discussion. The most striking character of this speciesis the discontinuous, slightly spiralling girdle kinetycomposed of dikinetids. Up to now, such a pattern wasonly known from Strombidium grande LEVANDER, 1894sensu CZAPIK (1976), S. glaciale PETZ et al., 1995, S.crassulum (LEEGAARD, 1915) KAHL, 1932 and S.rehwaldi PETZ & FOISSNER, 1992. In contrast to Strom­bidium spec. found by us, the left end of the girdle

Table 5. Biometrical characterization of Strombidium spec. M =median, Max =maximum, Min =minimum, n =numberof individuals examined, S =standard deviation, S, =standard error of arithmetic mean, V =coefficient of variation in %,x=arithmetic mean. All data based on protargol impregnated specimens. Measurements in urn,

Character Min Max x M S Sx: V n

Body, length 32 48 41.5 41 4.45 1.23 10.72 13Body, width 22 33 28.6 29 3.48 0.96 12.15 13Macronucleus, length 11 21 14.1 13 2.66 0.74 18.9 13Macronucleus, width 9 11 10.1 10 0.76 0.21 7.54 13Ventral kinety, length 12 17 13.8 13 2.22 1.11 16.13 4No. anterior polykinetids 17 18 17.3 17 0.5 0.17 2.89 9No. ventral polykinetids 9 13 10.3 10 1.19 0.36 11.59 11No. dikinetids in ventral kinety 14 17 15 14.5 1.41 0.71 9.43 4

Cell volume in !Jm3 8109 26799 18296 18850 5316 1474 29.06 13

Halteriids and Strombidiids from Coastal Brackish Water Basins 457

# , .

Genus Cyrtostrombidium LYNN & GILRON, 1993Cyrtostrombidium spec.

Description (Fig. 10). This species is very likely a newone. However, we observed it only in protargol slides,which is insufficient for a good description.P!otargol impregnated specimens 54-76x18-22 11m(x =62x21 urn; n =3). Body shape slim conical. Ante­rior membranelles surround an almost globular protu­berance. Macronucleus comma-shaped, 17-22x4-8 urn(n = 2) in size, contains spherical to ellipsoidal nucleoli.!"1icro~ucleus not. impregnated. Extrusomes insertingimmediately antenor to girdle kinety. Length of extru­somes in resting state 4 urn. Feeds on small (2-3 urn)coccal organisms of various taxa. Girdle kinety appar­ently continuous, composed of about 44 dikinetids(n =1), only one kinetosome each with stubby cilium.~entral kinety in longitudinal groove, length 21-40 11m(x = 33 um; n = 3), composed of 17-56 dikinetids(x = 35; n = 2), only anterior kinetosome each withcilium.16 anterio~ polykinetids (n = 2), in protargol impreg­nated specimens 1-2 urn apart. Paroral membrane not~ou~d. Cyrtos in cross-section elliptical, opening 10 11mm diameter, length of nematodesmata 14-22 11m (n = 2).Occurrence and ecology (Fig. 11). Cyrtostrombidiumspec. attained its maximum abundance and biomasswit.h 10000 ind.ll, 0.016 mg CII and 0.086 mgll wetweight on December 4th 1991 in the plankton of the

Fig. 1~..~bundancesof Cyrtostrombidium spec. at differ­ent Sah~Itles [%0] and temperatures [DC] in the Speicher­koog Dithmarschen and the Beltringharder Koog.

b

0:.:.. . .::.• -0 •• ••; .:. : : :::::::: : •• : : : . :- . ; ....::.

"' , 1 , 1

" " ' " I I ' , : I

cs -

Ma

Vk

a

,---"'---- Cyr

kinety is shifted posteriad in Strombidium grandeLEVANDER, 1894 sensu CZAPIK (1976) and both endingsare continuous with the ventral kinety. The girdle kinetyin Strombidium crassulum (LEEGAARD, 1915) KAHL,

1932 is circular with a small gap on the ventral area(PETZ et al. 1995), whereas in Strombidium spec. it isslightly spiralling and composed of less densely spaceddikinetids. Strombidium spec. is most similar to S.glaciale PETZ et aI., 1995 in size, shape, number of ante­rior and ventral polykinetids and the distinct anteriorprotuberance. However, the girdle kinety of S. glacialeis more posteriorly located and less spiralling. Addi­tionally, the left end of the girdle kinety is shifted lessa?teriad and the ventral kinety extends to the girdlekinety. Strombidium spec. differs from the freshwaterspecies S. rehwaldi in its higher numbers of anterior andventral polykinetids. Additionally, an anterior girdle ofextrus~mesas in S. rehwaldi were not found in the pro­targol impregnated Strombidium spec.

Figs. lOa, b. Cyrtostrombidium spec, a, b. Infraciliature of~entral an? dorsal side of same specimen after protargolimpregnation. APk =anterior polykinetids, CS =distendedc~ll surface, Cyr = cyrtos, Ex = extrusome, G = girdlekinety, Ma = macronucleus, Vk = ventral kinety. Scale bar10 11m.

I

458 S. AGATHA & J. RIEDEL-LORJE

mixo-polyhaline water basin of the Speicherkoog Dith­marschen (station DIll). The occurrence was limited tosalinities above 16%0 and temperatures above 3°C. Thismay be due to the only monthly sampling in winter andthe low densities of Cyrtostrombidium spec. during thistime. Highest abundances were found at salinities of16-28%0 and temperatures of 3-10 "C. Volume ofLugol fixed specimens 5107-42487 11m3 (x = 1184311m3; n =11), calculations based on conical body shapewith semiglobular top.Discussion. The genus Cyrtostrombidium LYNN &GILRON, 1993 was described from coastal waters nearJamaica. Later, it has been found in Southamptonwaters (LEAKEY et al. 1994). Its characteristics are theabsence of ventral polykinetids and the possession of acyrtos. Additionally, in the species known so far the gir­dle kinety is interrupted dorsally. Cyrtostrombidiumspec. is most similar to C. longisomum LYNN & GILRON,1993 in macronuclear shape and cell size. However, theprotuberance of C. longisomum is not hemisphericaland less prominent, the nematodesmata of the cyrtos ofCyrtostrombidium spec. are significantly shorter andthe girdle kinety is not interrupted dorsally. Furtherinvestigation is needed to decide whether these differ­ences warrant a separation from C. longisomum.

Genus Ciliospina LEEGAARD, 1915 nomen dubiumCiliospina norvegica LEEGAARD, 1915 nomen dubium

In the brackish water basins, flagellates with ingesteddiatom were noticed. Lugol fixed cells form a bulge(18-39xI6-24 11m) on the diatom, whose ends are onlycovered by a very thin layer of cytoplasm. In the bulge aring-like structure is found. The ingested diatoms mea­sured 34-102x3-5 11m. Despite such specimens lackmembranelles, they resemble Ciliospina norvegicaLEEGAARD, 1915, a ciliate with a bar perpendicular tothe cell's main axis. KAHL (1932) considered C.norvegica to be a "seltsames, deutlich oligotriches Infu­sor" deformed by diatoms. Deformed oligotrichs werealso found in the polder basins. In these cases, however,the ingested pennate diatoms were parallel to the cell'smain axis. Therefore, Ciliospina norvegica could eitherbe a flagellate, whose nucleus and flagellum give theimpression of a zone of membranelles, or -less likely ­an aloricate oligotrich ciliate, both ingesting pennatediatoms. In both cases, the genus Ciliospina and its sin­gle species C. norvegica are superfluous. Thus, they areregarded as nomina dubia.

Acknowledgements: This study was supported by the Fed­eral Environmental Agency, Environmental Research Planof the Minister for the Environment, Nature Conservationand Nuclear Safety of the Federal Republic of Germany(Grant 10802085/01), and by the state of Schleswig-Hol-

stein. This is publication no. 83 of the project EcosystemResearch Wadden Sea.We would like to thank K-J. HESSE and B. EGGE (For­schungs- und Technologie-Zentrum der Universitat Kiel,Busum) for the chemical analysis of the water samples.This article is based in part on a doctoral thesis by SABINEAGATHA in the Faculty of Biology, University of Hamburg,Germany.

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Acce pted: February 3, 1997

Authors' addresses: Dr. S. AGATHA, Zoologisches Insritut ,Universitat Salzburg, Hellbrunnerstr . 34, A - 5020 Salzburg,Austria; Dr. 1. C. RIEDEL-LoRJE, Institut fiir Frisch wasser­und Abwasserbiologie, Rainvilleterrasse 9, D - 22765 Ham­burg, Germany.