7-f /CIt

7-f /CIt
J. Protozool.,37(5), 1990, w. 414427
@ 1990by the S@iety ofProtozoologists
Revision of the GenusAskenasiaBlochmann, 1895, with Proposal of
Two New Species,and Description of Rhabdoaskenasiaminima
N. G.o N. Sp. (Ciliophora, Cyclotrichida)
KARI-HEINZ KRAINER* and WILHELM FOISSNER**
*Universität Graz, Institutfür Zoologie, Universitätsplatz2, A-8010
Graz, and
**Universität Salzburg, Institut
Jür Zoologie, Hellbrunnerstrasse34, A-5020 Salzburg,Austria
ABSTRACT. The planktonic ciliate genusAskenasla Blochmann, 1895 is reviewed and the new genus Rhabdoaskenasran. gen. is
established.Askenasia is characterizedby three circumferential kinety belts and a circumoral wreath of paired argyrophilic gränules
without recognizablecilia and nematodesmata.A "brush" is absent.Askenasia apparently lacks the key charactersof the Häptorida
and is thus transferredto the Cyclotrichida, family Mesodiniidae.Rhabdoaskenasradiffers from Askenasiain having singlefiles of basal
bodiesin all kinety beltsand club-shapedextrusomes.It possesses
a circumoral kinety composedof dikinetids from wliich nematodesmata
originate, forming a distinct rhabdos. Although very similar to Askenasiain its generalappearance,R. minima n. sp. could belong to
another order. Basedon an extensivereview of the literature and on silver impregnatedspecimensthe following I skenasiaspeciesare
recognizedanddescribedindetail:A.volvox (Eichwald,1852)Kahl, 1930,A.stellaris(Leegaard,1920)Kahl, lg3},A.acrostomian.
sp., and A. chlorelligeran. sp.Askenasiafaurei Kahl, 1930 and A. humilis Gajewskaja, 1928 aretransferredto the genusCyclotrichium:
C. faurei (Kahl, 1930) n. comb., C. humilis (Gajewskaja, 1928) n. comb. The systematicposition of the genusAskenasiais discussed
and keys to the generaof the Mesodiniidae and to the speciesof Askenasiaare provided.
Key words. Askenasia, Cyclotrichium, ecology,infraciliature, revision, Rhabdoaskenasian. g., systematics.
few species (two valid, two ofuncertain afrnity)
LI'ITHERTO
I I of the planktonic genus Askenasia have been described
[ 16, I 9, 27 , 37]. This is, however, not surprising because pelagic
ciliates are generally poorly explored. The outstanding study of
Faur6-Fremiet [9] is still the most comprehensive treatment.
So far, Askenasia l;,as never been investigated with silver impregnation techniques, and the species were simply separated
by body size and shape. However, the rather detailed observations of Penard [41] and Tamar [44] should be mentioned.
In this paper, the descriptions ofall nominalAskenasiaspecies
are reviewed and three new species, including a new genus, are
established using live observation and silver impregnation techniques. In addition, keys to the genera of the family Mesodiniidae Jankowski, 1980, and to the species of Askenasia are
provided.
MATERIALS
AND METHODS
Askenasia volvox, A. acrostomia, A. chlorelligera, and Rhabdoaskenasia minima were collected from the plankton of two
excavated groundwater ponds (each about 0.08 km2) eutrophified by drainage from agricultural areas (tl71 Dr. Hans Sampl,
report of Styrian provincial government; 15" 5' 5E,47" I.0. All
species were examined in vivo and in protargol impregnated
slides [21]. Note that this staining method generally causes
shrinkage of the cells of about 20-30o/o. The silverline system
was studied in specimens of an undetermined species impregnated by a "dry" silver nitrate technique [20]. All measurements
were performed at a magnification of 1,200x. Statistical procedures follow methods described in Sokal & Rohlf p2l.'ftre
drawings of the impregnated specimens were made with the
help of a camera lucida. Where possible, the type individual
KRAINER & FOISSNER-REVISION OF ASKENASIA
was used for preparing the figures; otherwise, composite drawings were made.
Prior to estimating the number of individuals, subsamples
were fixed in HgCl, and subsequently stained with about l0
drops of a solution of 0.040/obromophenol blue and sedimented
overnight [4]. Counts were performed on slides at a magnification of 100x. Abundance is expressed as cells per liter. The
standing crop, expressed as mg per m3, was calculated by using
the estimated cell volume of protargol impregnated specimens
(reducing the complicated shape to a simple geometric figure
and assuming a specific-gravity of 1.0; a method widely used
by hydrobiologists), multiplied by the abundance. Although this
is a rough method, the values give some figure of the biomass.
Holotype and paratype slides (protargol impregnated) of the
four new species have been deposited in the collection of microscope slides of the Oberösterreichischen Landesmuseums in
Linz, Austria. Accession numbers: 7 6/ 1989-83 / 1989.
4t5
usually causesimmediate lysis. Extrusomes occur in several approximately pinJike types which are packed in bundles surrounding the
cytopharynx, but often a few are scatteredthroughout the cytoplasm.
Shapeand arrangementof the extrusomesrepresentimportant species
characters.Askenasia speciesfeed on algae and other protozoa U 5, 441.
Ingestion and defecation have, however, not been observed.
Locomotion is a highly characteristicfeature in the genus(Fie.2,3).
The "pectinelles" of the pre-equatorial kinety belt (PKB) beat in a
rotating ring consisting of 5-16 flamelike tufts, impressively visible
during the immobile period (Fig. 3). They draw food particles toward
the cytostome,while the cell rotates leisurely around the transverseaxis
[44]. The lightning darts and short, spiralling jumps, which alternate
with abrupt stops, are causedmainly by the bell-shapedskirt, formed
from the "cirri" of the equatorial kinety belt (EKB), pushing the water
backwards.It is also evident that the cirral-skirt, when immobile, keeps
the cell afloat. The bristles of the subequatorial kinety belt (SKB) act
as stabilizersduring floating but may also play a role in forward movement by contracting [4], 44].
Three belts, ofdifferently arrayed cilia, mantle the anterior portion
(Fig. 1, 2). Each belt is composed of (47-)6O-7Oroughly longitudinal
RESULTS
kineties and separatedfrom its neighbor by a small gap. The 8-15 pm
Nomenclature. The genus name, Askenasia, is a junior synonym long pectinelles(P) originate from the pre-equatorial kinety belt (PKB),
whose kineties are composed of single files of basal bodies and are
establishedby Blochmann [7]. It has to be retained in accordancewith
the IRZN, article 23, becausethe senior name, Stephanidina, rs con- interconnected by transversefibers. The equatorial kinety belt (EKB)
bearsthe rigid, sickle-shaped,about 2O-30 pm long "cirri," which form
sideredas nomen oblitum 1231.
Thereis much confusion concerningthe synonymy and nomenclature a skirt around the posterior half of the cell. Each cimrs is composed of
ofthe type species,A. volvox. It was originally describedby Eichwald a double row of basal bodies arrangedin zigzagsand interconnectedby
|61 as Trichodina volvox. Furthermore, he proposed to establishSle- an argyrophilic fiber. The subequatorialkinety belt (SKB) contains 20phanidinaas a new genus for this species.Trichodina volvox was then 60 pm long, flexible bristles. Each kinety is obliquely oriented to the
transferredto the genus Halteria [3]. At the end of the l9th century longitudinal cell axis and comprises ofthree basal bodies, usually inBlochmann[7] published A. elegansas a new genus and species,un- terconnectedby transversefibers. The posterior portion shows oblique
fortunately overlooking the valid original description as well as the singlefilesof non-ciliated granules(PG, smallerthan basalbodies)which
redescription[3]. His name is thus a synonym. Kahl [33] recognized usually lie in the center of weakly impregnated square stmctures, prothe synonymyof Halteria volvox and A. elegansand consequentlydes- ducing a more or less regular lattice. However, A. chlorelligera differs
ignatedBlochmann'sspeciesasA. volvox(Claperöde& I-achmann,1859), noticeablyin the absenceofthese linear files and in possessinga network
but also disregardedthe original description; hence listing the wrong ofpolygons resemblinghoneycombsand enclosingsingleor paired granauthor and date. Finally, Dingfelder [15] lst mentioned the original ules. This network correspondsclosely to the silverline system(cp. Fig.
descriptionby Eichwald, but incorrectly stated "Blochmann, 1895" as 4 with Fig. 50).
The cytostome-cytopharyngealcomplex is located in the long axis of
the lst revising author. However, Kahl is the lst revisor and the correct
citationof the taxon must be "Askenasia volvox(Eichwald, 1852)Kahl, the cell and is usually equipped with conspicuous extrusomes. The
cytostome, lying somewhat depressedin the center of the anterior pole
l 930" [23].
Generalmorphology and ecology oI Askenasia(Fig. 1-4). The size (oral area), is round to slitJike [44]. The oral area is encircled by a
remarkable "circumoral wreath of unciliated, paired granules" (CWG),
rangesfrom 27-60 prn in length and from 22-65 pm in width, with
lengthand width usually approximately equal. The body has an ovoid which has a circular or more or lesscloverleaf-shape.Each pair usually
to diamond-shapedoutline and can be divided into an anterior cone- comprisesofa larger posterior and a smaller anterior granule. Both are
shaped"rostrum" and a posterior hemispherical portion, both circular slightly inclined to the cell's long axis and are ofequal size in A. chloin transversesection.The cell equator representsthe transition between relligera. To date we are unable to decidewhether the granulesare basal
theanteriorand the posterior portion, which doesnot alwayscorrespond bodiesor mucocystsor somethingelse,and whetherthe smaller satellites
to the geometricalmedian plane of the cell. The shapeof the rostmm are parasomalsacsor not. Accordingly, we prefer the term "circumoral
variesfrom sharply truncated through arched to tapered.The posterior wreath" to "circumoral kinety." The granulepairs are usually associated
with weakly impregnating fibers (longitudinal fibers, LF), which course
portion is broadly rounded to bluntly pointed.
A singleglobular to ropelike macronucleusis situatedin the posterior posteriorly to the pre-equatorial kinety belt (PKB) and anteriorly to the
portion or just below the cell equator. Occasionally, specimens(pre- cytostome (transversefibers, TF; Fig. 2). The CWG is an important
sumably postconjugates)were found with up to 10 globular segments. diagnostic feature at specieslevel. There is now strong evidence (cp. l.
two macronuclearsegmentsand volvox) thatthe apical star-like figure in l. stellaris,which Kahl assumes
Exceptin A. stellaris, which possesses
two micronuclei, a singlesphericalmicronucleusis attachedto the mac- to be pharyngealwrinkles, is also a CWG (Fig. 27,30).
The silverline systemis widely meshed,both in the posterior portion
ronucleusin variableposition.
One, two or four contractile vacuoles dischargeby conspicuousex- and in the oral area,whereasthe middle cell area showscircumferential
cretory pores subequatorially.The vacuole is either a simple blister or bands ofrectangles, and, subjacently,honeycombedstructures(Fig. ).
Bipartition by transverse fission (homothetogenic fission, [44]) has
is surroundedby collecting vesiclesduring diastole. Multiple vacuoles
are diametrically opposedand function alternately. No data are known not yet been studied in detail. It begins in the equatorial kinety belt
vac- with a constriction [41]. The related gents Mesodinium showsno conon the cytoproct. Three specieshave an enigmatic crescent-shaped
uole on the rear (we suggestthe term "terminal vacuole") which is striction during bipartition [45]. The macronucleusappearsdumbbellhyaline and often disappearsin vivo. Protargol slides show that it ad- shaped in the late fission stages(Fig. 13). The proter reorganizesthe
heresto the posteriormost transversebristle row. The bristles are bent equatorial kinety belt, the opisthe the pre-equatorial kinety belt, while
posteriadforming a basket-shapedstructure which enclosesthe vacuole the reorganization of the bristles has not yet been observed. The pec(Fig. l; TV). Whether the vacuole contains an air-bubble or some sort tinelles are active before the dividers separate.Conjugation occurs by
of liquid is not known. Nonetheless,we suggestthat it has a special fusion at the anterior end (Fig. l4). During conjugation the pectinelles
function in the planktonic mode oflife, possibly increasingbuoyancy. do not ceasebeating (Fig. 16). The fragmented macronuclear material
Mesodiniumpulex Claparöde& I-achmann, 1858,was observedto also is presentin the anterior portions ofthe conjugantsl4l , 441.The resting
cyst is known only for A. volvox [4 I ]; it consistsof two shell-like parts
have such a terminal vacuole [8].
which are equipped with spines(Fig. l0).
The pellicle is ribbed (seenonly in optical transversesection, with
Despite extensivebiogeographicdata, little information on the ecolthe cilia extending between the ribs) and fragile. Coverslip pressure
416
J. PROTOZOOL., YOL. 37, NO. 5, SEPTEMBER-OCTOBER I99O
LF
PKB
SKB
PG
Fig. I -4. Schematicfiguresof lske nasia lllustrating diagnostic features.1. Side view. 2. Three somatic kineties showing arrangementof basal
bodies and fibers usually recognizablein protargol impregnated specimens.3. Motion study ofpectinelles as seenfrom anterior pole, showing
characteristicflame-like tufts formed by the PKB. 4. Silverline system of lskenasia sp. after dry silver nitrate impregnation. Abbreviations. B,
bristles; C, "cirri"; CWG, circumoral wreath of granules; EKB, equatorial kinety belt; LF, longitudinal fibers; P, "pectinelles"; PG, posterior
granules;PKB, pre-equatorial kinety belt; SKB, subequatorialkinety belt; TF, transversefibers; TV, terminal vacuole.
KRAINER & FOISSNER_REVISION OF ASKENASIA
4t7
(Fig' 5-20)' Sizein vrvo
Description accordingto data from literature
as well as marine ecosyspm 17,.33,4r,44]' Shapeovoid to pvriform'
osv is available. Askenasrainhabits limnetic
i-27(-50)
zs-az(-;,)-;
;;;;L-"-Ji,1;r
fi";
täs, preferentiallythe prun[to*-ii *as recorded
tutu"rorr.."i",.,.globulärtoellipioid(12-14'5x9'5-ll'5pm;[44])'conA.vorvox),butisstill,rotao"rr-..rt"orropm in diameter' very
intheholarcticregion(see
tains srnall chrömatin globules' Micronucleus 3-4
*""nv
e"orvrt"-,,trtl"nlriäi.
vesicles
with
collecting
[44]' Terminal
the southernhemisphere.In freshwater
vacuole.
p"r"- singr" .ontractrJJ
censiües*i"nip.r"ä""ä
foundin resspolluted hablrars,achieving highest
bv Penard [41] as artifact of coverslip
ii"rl"i,-r!i1PT."^t:d
.ur"*j."ääI"Ä;";
"u""or"
fall when algaeare abundant l33,39,unpubl.
iil. parr"i" fairly iragile, flexible [44]' About 10 thin'
and generallyprefers oligo- to p."r"..."'1-Fig
("trichites")' approxlconcludethatAskenasia*
n""ar"-.rräpäd, conlcattv bundled extrusomes
""Jr"*i""lc
hvaline to vesicurar,
Cvtoplasm
mesotrophicconditions. uräri".äääiääi.;i ;;;;,ig"ti"it
44r.
lensth
in
"i\täittio
t4r,
-ut.rv iiliz'pm
promiseto be worthwhur.,..n".:"oror"1
gänules G'lg' t s)' In addition' spheres2-3
tiriv
and
::^::::,
contains
in
our
ätou,ries
valid species
Taxonomicchanges. askenasiacomprisesfour
irregular massesas werl as yellow
- to ,- i" oiu--"t*, aart o"at larticles,
andA. humitis, ought
Bodo-remnants)are rec(presumably
opinion.Two othe_r."-iJrp""i
yellow
inclusions
gt*"itrt
and
",,s.'fourri
4r,44]Fig' 9' 15' 19'
([33,
be transferredto L:yctotnchium.
pectinÄrtar
tufrs
12
ä"" to
rsr describedas
Cycrotrichiumfaurei(r{ahr, 1930) nov. "9Tb; rul
"g.ii"üi"i+?t1
about 60 kineties [7, 34, 41]; according
of
compoied
belt
eu"hn""iy
zör.
*rtrr
it, ir, äg.""-"nt
pre-equarorial belt kineties-composed of
Askenasiaeregans rrgl.Kahl t33r later classified
i"'iÄit
iär' ontv 4148..
Faur6-Fremret,as a new species,A. faurei. .Aske"rrt;';;;;;',';;;;;;;,
their;ilia about 8-13 pm long [33' 44]'
each,
uoär"r
turr
utorrtlo
racksbristles,has a ci'ateä posieriör portion ""a3'Jö"'"""ti""til" u." ci..,
rows of l4-17 basal bodies each' cilia
adjacent
of two
rl. rneseäaiu"t.r,
"o-por"o 20 pm long' Bristles30-40 pm in length 133'441'
vacuolewith colrectingcanatJi' tt " rear (Fig. z
uppto"i,,,ät"fv
typicalfor Cyclotrichiumtlg, 33, +Zl. Atclotllc.!1!\fau'ei,however'
Askenasia volvox is widespreadin limnetic
o;;;;;;;
ii'i rr-"- rure speciei
""orogi' the prankton of lakes [1, 6, r 5, 3 I ' 36' 39'
"td
requiresredescription basedon silver impregnuti.n.
pr"oo--u"tly-in
habitulr,
ii
reportedonly twice since the original description t5,
abizane- io,ii',iö,ill,buthasarsobeenrecordedfrombenthichabitats[2,3'
1928)nov."o-t.i'
cvcrotrichiumhumiris(Gajewskaja,
rz,rs,z8j.oäiu"nabundancesarerare.Hunt&chein[3llfoundl26
C.iairei,t*ohr,"tv^f"itru.,or.irrg"surfacewaterin
shapedspecies,whichhaslliL
11
iil.
belr
kinety
eie.
equätorial
ihe
Lake
3t9
mesotrophic
In
the
like cilia associatedwitn
(New
York)'
".ilrolu"'".J"ierminedzskenasia-speciesperliterof
lake
recorded .i;;; ,hJ original th" "i;;;;;hi",c"y"e"
t":*""."
2'800
(about
in
June
observed
requiresredescriptron, d has.not
were
densities
hitheJt
.k""^i$"Ä;;t
""ä'i".-i"i-t""n
grouped wrtt Halteria grandinella
descriprron.
:*"
anterior kinety 99!r-.o"i liter, but ihe number was
singre
a
onry
indiCycrotrichiumhas
of
The type species
to be a beta-mesosaprobic
is
considereä
ßsl).'";ti;;;t;-ioiot
ponds with
c.rrrrii^ü"ö.humirß,"ä"rr*rtr'iiäti""ivu"rtJ,
from
recorded
been
bert[33].Therefore
also
ittras
How^ever,
rp""i". ii+1.
maybe transferredto a new genusin the l+ture.
"uto.
w^ith:(i) one circum- beet-wastesof a sugar factory [29]'
Mesodiniidae
*äÄi*
1)'
,1-s
of
rtiagnosis
Irnproved
of ai Austrian poporution (Fig' 35-38, 56-58; Table
cir"rr-r"-."r,äui,
_ o"r"ripiion
Diameter'
plump-pyriform'
oralwreathofargyrophilic granules;(ii) three
outline
x
"quatoriar
3oas
im'
3545
r"-"i"o
nr". or st.
c-shaped' usuallv with
kinetybelts (kineties of pre_equarorial.beltcompo,sää.ngr" rows of in"t,rähg cirri, auout
Jräo"üi.
90 f-:.Macronucleus
varioussize(Fig'35,56)'Some
basalbodies, kineties of equatorial belt composed
pornt!ä?nJr.'chromatinbodiesof
ina^zigzag,kineti.esorr,ru"qiuto.ruibelt"o-Singleconlractile-vacuolewith
basalbodiesarranged
n""ore or pin- ip""i"in. *lihE5 sphericalfragments'
o.'f,r.
(iii)
.,-,ot"
and
eictri;
bodies
length, at canal base about 3
posedof three uasal
pm
in
4-6
canat
Free-riving, car"^"."lory
(Fig' 35)' Extrusomes 15-22
"onrpi".,o,r. pore
shapedextrusomes,usuary surrounding.cytopharynx.
pm.in
diameter
2
about
,-,
"i """"r
nivorousand argrvorous,freshwater and marine.
by virtue of extruded extrusomes?)'thickened
rc"gtrt
rä"g
t""ö-g
1930.
'Kahl,
1852)
Type species. errcrorä-"it'ri*-@ichwald,
orAskenasia
orSpecies
toandDescription
Key
ä;:ö?iJr*Ti:::tlf."ltl.";:Xt}:iär#rllX'ilir""Y*?,,tlf;üJ'lä
2 ciliatei (piesumably Urotricha spp' Fig' 35)'
I Two or more contractile vacuoles
3
.
.
.
.
.
.
.
.
su.ur'foJi"rofitKg-kinetiesettipsoia,presumablybecauseofim_Singlecontractilevacuore
fibers (Fig' 36' 37' 57)' The EKB-kineties
tlttu""'"t'"
pt"g;;t"ä;;;;t
vesicles' diametricallv
2 Two contractite vacuoiel wiitr coitecting
apart' basal bodies denselv
kinety-wiäth
one
uUou'
;C-;lä,
;"[Ü
macronu,ctgarseementr.lo:opposed.Two sausage-shaped
t r u m s h a r p l y t r u n c a t ä d ' E x t r u s o m e s . o o . s t , a p e ä ] a r r a n g e d i n ' p ä " " ä t F i - g ' i 0 , 36asal
. 1 , 5 7body
) . T h emarkedly
S K B - k i nsmaller;
e t i e s a l no
m o transverse
s t r e c t a n gfibers
ularlybent,
;;h;"dtrmost
twowhorlsorsi*u,rnäJeseult''cwcl"ptraryngälwrin-kles")'
pairs of cwG form 6-12 archGranule
z!,,Jt,57).
stittaris
.'Ä't"ritio
;;;;s;i;ä;iFie.
.
.
.
(Fig'
cloverleaf-shap"o*iir, o-s robes.Marine
'iup?J rou"t"teiembling a compounded three- or four-leafclover
- Four contractile vacuoles' Singlehorseshoe-shapeJtacronuclepattern of
elaborate
an
form
fibers
andlongitudinal
lg'i8j' iiuÄ"erse
neeore-ritewith pointed ends'
us.Rostrum tap"'"o"i*ti'''äes
(Fig' 38)'
Freshwater . . . .
inrr..t"o v's, their tips pointing toward cytostome
arleasrzhorceu r"nJtf i;;;.'öwc;i."ular.
;"a ecolägy. Although never abundant, the Austrian
... . . A. auostomia
o;;"";;
found
p"p"i"ti." t r""nd duririg all seasoni.The highestnumbers were
spheroidal to ellip1986(170
3 with symbiotic green utgu". tutu".onucleus
october
in
and
mglm')
4.3
titer;
protruding
by
i"'Iü;;1t-8; iiit
soid. Rostrum t..,.r"uäd, apically crown-like
pätlit"i )-! ""[r-pätrrerowestnumbersin Julv 1986and February
pin-shapediypes' cell
extrusomeuunorer. e"-iÄroir". in two
""ilt iaut"h r'ss7.ry-/m);
Fiigh numbers were also observedin December 1986
.
.
..
.
pentägonäi
u"o
.
shapenot pv.lior-. ö*ö apf.o*imutety
r:;::(r'r:Y;r!;t'* !:t-"yllni*lJi*g*:*inJanuaryle87(150ce'sperriter;
uutorten
uieu",
_ wiir,oui
,v-uroii.gi"",,
",
re20)Kahr,1e30
(Leegaard,
steuaris
Askenasia
äffi:o:lT.ffi:l:;
X'f:L,ililfj,Xl:::H"rä":ä::,fff
CyG_,..^.pyriform.
stellaris Leegaard, 1920'
shape roughly
needle- or rod-shaped. Cäil
.......
ctoverleaf-shap.a.iiirr'e-rzlobes.Freshwater
Synonyms. Lohmanniella
zs-ra). Size invivo 24-50 x 29-65 pmlS'34,
;ä;;li*t";lrig.
32).
lzr. i"nili_st ap"Jto so-e*hat flauenedglobular(Fig. 23, 29, 3t ,
1930
t.uncuted, posterior portion dish-shapedto bluntlv
i;;,;;höy
Askenasia volvox (Eichwald, 1852) Kahl.
lobes
poini"Jtrig' ii, lzl oral.aiea shows star-like figure with 6-8
Halteriavolvoxcla(Fic' 2'7' 30' 34)' Two sausase
synonyms. TrichodinavolvoxEichwald,1g5?
cwc
a
likelv
very
ostome,
ntgil^ Biochmann, r 895.
paröde& Lachmann, Ä\gi )ii-Äiio
"i
"n"t."titrg
macronucleaisegments'eöcentricallylocated in cell
to *Äi-l.rtuped
([8]
Surprisingly,wedionotfindaformwhiöhcorrespondsexactlytoany
eachpait enclosedin specialmembrane
however,
observed,
of the availabredescriptionsof A. vorvox.we
17 x I LLm[8]' Two micronu"
"o";;;;?iri.'2a,,2s,33),
part
upp.oii*ut"ly
of
each
zo),irze
rig.
*u"Äoie c-rhup"d
rathersimrlar specreswhich differs only bv the
crosely attached to rnner concave
iniiiuilv, wä aeciaea clei, about 4 pm in diameter each,
ronucleusand the conspicuous excretory .u.rur.
segments(Fig' 33)' Two contractile vacuoles
micronuclear
po.tion
of
*as
.rie*
iiri,
ho*".r"r,
29'
that it should be described as a new species;
decision withcollectingvesicleslocatedequidistäntlyfrommacronuclei(Fig'
by one of the reviewers.Thus, we withdraw our
discouraged
about 20 pm in length' arroä-shaped'
("trichites")
E^t."sories
r:1.
rhis
wlr ueuruEwhether
.es"aict *ili'ä."r0"
ir,"r" researcn
)tions. tsuture
each,probur separatetne aes"npäänr.
."rilä i, t*" whLrls of six bundleswith 12-20 extrusomes
waswlseor nor.
A.volvox
418
I99O
J, PROTOZOOL., YOL. 37, NO. 5, SEPTEMBER-OCTOBER
a\'
oo
oo
#'1!
-)<v(
\16
1\z
i\ "'
,\ zo
\N\#1
,u---Ä
CTTV
,----'t
7,
S=,
7' After
23-34, A. stellaris. 5, 6. Lateral and anterior view after Eichwald [16]'
Fig. 5-34. 5-20, A. volvox, 21, A. faurei, 22, A.. humilis,
view' Note
side
11'
cyst'
Resting
10.
gloctrmann
Penard
after
1ö-16,
t4llg,
[7].
claparöde & I_achmann[13]. 9. Lateral and *t"rio. "i"* äfter
14'
13. Bipartition. Noie constriction and dumbbell-shaped macronucleus'
spherical macronucleus. rz. siä" view, showing t".-i.rui'r,u"ool".
pectinellesof conjugants' 17-20' Side and
view,
showing
Anterior
16.
pectinelles.
of
nu-"Im"^ton,
conjugation. 15. Antenor vie*,-srro*ing
after
p."ii.r"u.r, skirt of equato.iat uett of'cirri and bristles' 21' A' faurei from Kahl [33]
anterior views after Kahl [33, 34], showing tufts of
protruded tips of
Note
view'
side
23.
Borror
ix",
il-ia,
[8].
n-al. A. stetlaris.
Faur.-Fremiet 1rgl. zz. e-. humiris after Gajewskaj iiäi.
4t9
KRAINER & FOISSNER_REVISION OF ASKENASIA
+
a_a+
<--a-a-a-a-ar
-o+a
-a_a.<_41
-a-a
--a.-a
\a_a_
-
_-l_.-'
36
Fig.35-38. A. volvox (Austrian population), from life (Fig. 35) and protargol-impregnatedspecimens(Fig. 36-38).35. Side view, showing
nuclearapparatus,contractile vacuole, extrusomes, and pharyngeal basketsof ingested ciliates (PB). 36. Details of somatic kineties. Note thä
threebasalbodies ofa Sl(B-kinety (arrow), the anteriormost basal body ofwhich is distinctly smaller.37,38. Infraciliature in side view and in
obliqueanterior view, showing cloverleaf-shapedcircumoral wreath of granules(CWG) and longitudinal fibers (LF) producing V-shaped pattern
in oral regiontogetherwith transversefibers (TF). Note lattice pattern in posterior portion. Bars : 10 rrm.
F
extrusomes
on oral area. 24. Apical view oforal area, showing whorls ofextrusomes. 25. Longitudinal section, showing extrusome ("trichite")
bundlesand contractile vacuoles. 26. Cross-section,showing worm-like macronuclear segments,tips of extrusome bundles and two contractile
vacuoles.27,28, after Leegaard1371.27.Anterior view, showing hexagram-like("hexaster") figure. 28. Side view, showing extrusome tips. 2934,after Kahl [33, 34].29. Side view, showing truncated oral area and doubled contractile vacuole with collecting vesicles.30. Apical aspectof
oralarea,showing eight arch-shapedlobes encircling cytostome. 31. Side view of early fission stage.32. Starved specimen. 33. Cross-section
showingmacronuclearsegments,rnicronuclei and contractile vacuoles.34. Anterior view, showing pectinelles,cirri and bristles.
420
J. PROTOZOOL., VOL. 37, NO. 5, SEPTEMBER-OCTOBER I99O
:
a
ttta
a
i
4;).
s
t
t,t
a
2
1'-/
r.
40
41
Fig.39-43. Askenasia acrostomia n. sp., from life (Fig. 39, 40) and protargol-impregnatedspecimens(Fig.4143).39. Side view, showing
pellicle (PE) and terminal vacuole (TV).40. Extrusome.4l. Detail of a somatic kinety. The SKB-kinety (arrow) consistsof three basal bodies.
42. Infraciliature in side view. Note protruding tip of conical extrusome bundle (EX). 43. Infraciliature in oblique posterior view, showing
macronucleus(ma), micronucleus (mi) and contractile vacuoles (CV). Bars : l0 pm.
KRAINER & FOISSNER-REVISION OF ASKENASIA
421
I\.\\,
t,,r(i$,lt1
.1
Crn e
c(Vc O
Fig. 44-50. A. chlorelligeran. sp. Fig. 47, 48 after Kahl [35], other originals from life (Fig. a) and protargol-impregnatedspecimens(Fig. 45,
46,49,50).44. Side view, showing the two extrusome types, nuclear apparatus,contractile vacuole (CV), pellicle (PE), terminal vacuole (TV)
and symbiotic greenalgae.45. Extrusome types. 46. Detail of a somatic kinety. SKB-kinety (arrow) consistsof three basalbodies and EKB-kinety
has ashort "dil" at posterior end.47. Side view, showing truncated oral area, extrusome bundles, symbiotic green algae. 48. Apical aspect
showing radially arrangedbumps ofextrusome bundles,resemblingcross-sectionofapple-core. 49. Infraciliature in oblique anterior view, showing
pentagonalcircumoral wreath of granules(CWG). 50. Infraciliature in oblique posterior view. Bars : l0 pm.
422
J. PROTOZOOL.,VOL.37, NO. 5, SEPTEMBER-OCTOBERI99O
'M14i;
SP
lt
N
52
\\tl/D,
h
N
WILI
'/,ti
'€
/el
tq
.J
,/t?.
'p'
at
I
uJ-^+:?''
I
54
Fig. 51-55. Rhabdoaskenasiaminima n. sp., from life (Fig. 5l) and protargol-impregnatedspecimens(Fig. 52-55). 51. Side view, showing
nuclear apparatus, contractile vacuole, extrusomesand lithosome-like inclusions (LI). Note spirills (SP) on surface of rostrum. 52. RhaMos,
"armed" with extrusomes,slightly schematized.53. Infraciliature in oblique anterior view, showing nematodesmata(N) and transversefibers
(TF). 54. Detail of a somatic kinety. SKB-kinety consistsof only two basal bodies (arrow). 55. Infraciliature in oblique posterior view, showing
macronucleus(ma) and pore of contractile vacuole (P). Bars: l0 pm.
Feeds on cocci and algae. Kinety
truding from rostrum (Fig. n2r.
belts comprise approximately 70 kineties. Pectinellesbeat in 6-16 tufts
[8, 34]. Bristles from 2G-60 pm in length [8, 34].
Occurrenceand ecology. This specieswas discoveredin the plankton
of coastal waters of the Finnish Gulf (easternBaltic Sea), numbering
1,540 cells per liter at a depth of 20 m [37]. It has also been recorded
from coastal waters of the North Sea near Hamburg, FRG [34], from
diatom detritus ofAlligator Harbor, Florida [8], and from littoral sands
of the KandalakshaGull White Sea,USSR [101.
Remarks. This marine specieswas originally described under the
name Lohmanniella stellaris. It was transferred by Kahl [33] to the
genusAskenasia.Askenasiastel/arusis the solemarine speciesdescribed.
It is well characterizedby its nuclear and excretoryapparatus.However,
redescription with silver impregnation techniquesis required.
Askenasia acrostomia n. spt.
Diagnosis. Size in vivo 40-50 x 30-40 pm. Circumoral wreath of
granulescircular. Macronucleus horseshoe-shapedto ropeJike. Extrusomesneedle-like with pointed ends. Four contractile vacuoles.
Type location. Excavatedgroundwaterponds near Graz (Styria, Austria).
423
KRAINER & FOISSNER_REVISION OF ASKENASIA
56
61
65
tl
66
Fig. 56-66. Askenasia spp. Infraciliature after protargol impregnation. All bars indicate lO pm. A. volvox, AustÄan population (Fig. 56-58).
Fig. 57 and 59 are composites formed by superimposingimages ofdifferent focal planes to provide a clear view ofthe total surfaceofthis large
ciliate. 56. C-shapedmacronucleus(ma) in optical cross-section.57. Side view. Note subequatorialkinety belt (arrowhead).58. Oblique anterior
view showing cloverleaf-shapedcircumoral wreath of granules.59. Side view of A. acrostomla n. sp. Rhabdoaskenasiaminima n. sp. (Fig. 6G63).60. Side view. Note circumoral kinety (arrowhead).61.Oblique posteriorview.62. Optical longitudinal sectionshowingnematodesmata
(N).63. Optical longitudinal section showing extrusomes(arrowhead)and macronucleus(ma). A. chlorelligera n. sp. (Fig. 64-66).64. Oblique
posterior view showing honeycombJike polygons and macronucleus (ma). 65. Apical aspect of oral area showing five bumps of protruding
extrusometips, enclosedby the roughly pentagonalcircumoral wreath ofgranules (arrowhead).66. Optical section, showing symbiotic greenalgae
(arrowheads),extrusomes(EX) and macronucleus(ma).
424
J. PROTOZOOL., VOL. 37, NO. 5, SEPTEMBER-OCTOBERI99O
Fig.67-70. Schematic figures of the genera of the Mesodiniidae (from several sources).67. Myrionecta Jankowski, 1976.68. Mesodinium
Stein, 1867. 69. Rhabdoaskenasian. gen. 70. Askenasia Blochmann, 1895. CWG, circumoral wreath of paired granules;EKB, equatorial kinety
belt; PKB, pre-equatorial kinety belt; SKB, subequatorialkinety belt; TV, terminal vacuole.
Derivatio nominis. "acrostomia" refers to the tapered rostmm.
Description (Fig. 39-43, 59; Table 1). Outline approximately rhomboid with distinct cell equator (Fig. 39). Anterior portion tapering, constricted at level oforal area,where a singleextrusomebundle protrudes
(Fig. 39, 42). Well-fed specimenswith globular posterior portion. Macronucleus with chromatin bodies of various shapesand sizes(Fig. 43).
Several specimensobserved with two sausageJikefragments (resemblingA. stellaris).Micronucleususually locatedat end of a macronuclear
arm (Fig. 43). Four contractile vacuolesdiametrically arrangedin posterior 3rd ofcell, discharying by short excretory canals about I pm in
length. Basesofexcretory canalsframed by argyrophilic fibers (Fig. 43).
Extrusomes about 23 pm long, extending atleasl2/t ofcell length posteriorly from apex (Fig. 39, 40). They usually discharge on fixation,
forming tanglesofthreads; in protargol slideshaving knobbed posterior
ends not discernible in vivo. Furthermore, impregrrationssuggestpresence of a 2nd, shorter type. We have not, however, ascertainedit in
vivo. Cytoplasm of starved specimens,colorless in posterior portion
some greasily shining inclusions. Feedson algaeand ciliates. Terminal
vacuole discernible in vivo (Fig. 39).
The EKB-kineties are approximately two kinety widths apart with
425
KRAINER & FOISSNER-REVISION OF ASKENASIA
Table 1. Biometric characterization of Askenasia volvox (Av), A. acrostomia (Aa), A. chlorelligera (Ac) and Rhabdoaskenasiaminima (Rm)."
Character
Body, length
Body, width
Macronucleus,longer axis
Macronucleus,width
Micronucleus, diameter
No. granule pairs of CWG
No. dikinetids of circumoral kinety
Distance CWG to PKB
No. basal bodies per PKB-kinety
PKB-kinety, length
No. EKB-kineties
EKB-kinety, length
No. basal bodies per SKB-kinety
Species
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
Av
Aa
Ac
Rm
'SDCV
37.8
32.2
27.2
25.5
34.6
28.6
26.5
19.9
24.9
22.8
t2.5
t4.5
7.1
5.2
8.3
6.1
z-)
1.9
1.8
2.2
58.9
32.5
54.4
28.6
2.4
2.0
2.1
1 3 I.
11 . 9
r0.2
6.7
5.9
7.4
4.4
4.3
60.2
73.2
57.4
62.2
10.0
5.9
5.6
4.7
3.0
3.0
3.0
2.O
4.O
5.2
2.9
3.8
4.4
4.2
5.1
3.8
4.1
0.8
2.4
2.7
1.5
1.4
r.9
1.7
0.2
0.5
0.7
0.5
5-q
2.9
4.4
z-J
0.6
0.8
0.6
2.9
2.6
1.8
1.6
1.0
t.2
1.0
0.9
0.7
3.6
2.5
2.7
1.5
0.9
t.4
1.0
0.0
0.0
0.0
0.0
10.6
1 6 I.
10.7
16.3
12.8
14.7
t9.2
1 9 I.
16.5
3.5
19.2
18.6
2t.l
26.9
22.9
27.9
8.7
Min
Max
n
30
22
24
18
25
24
22
l6
t7
22
l0
l1
5
2
6
5
42
37
t4
t7
JZ
ll
l5
2l
53
30
48
22
63
39
60
I
I
A
zo.5
38.9
22.7
5.8
8.9
8.1
8.0
25.O
40.0
28.6
22.1
21.8
17.6
23.9
r6.9
t6.2
22.7
20.9
1.2
4.9
4.3
4.3
15.0
15.2
25.0
2t.3
0.0
0.0
0.0
0.0
30
^1
37
38
26
JI
24
l8
22
t2
8
t2
l0
2.4
2
2
J
2
9
9
8
Ä
5
6
4
4
59
IU
54
57
8
5
5
A
)z
1A
l8
l8
t2
9
7
10
6
7
6l
78
64
66
t2
8
l0
7
J
J
J
J
J
J
2
2
ZJ
ll
l9
t2
5
t2
t7
16
z5
t2
t7
l0
t4
l0
10
8
8
l3
t4
l6
10
10
9
ZJ
6
22
t7
ll
10
t7
t2
6
t2
9
l6
28
l0
l6
l0
19
7
I7
. All data are based on the investigations of selectedprotargol-impregnatedspecimens.All measurementsin micrometers. CV, coefrcient of
variation in o/o;CWG, circumoral wreath of granules;EKB, equatorial kinety belt; Max, maximum; Min, minimum; No., number; PKB, preequatorial kinety belt; SD, standard deviation; t, arithmetic mean.
basal bodies loosely spaced (Fig. al, 42, 59). The SKB-kineties are
interconnected by transverse fibers (Fig. 41, 42, 59). Granule pairs of
CWG do not show fibers under impregnation method (Fie. aD.
Occurrenceand ecology. The highest numbers were found in May
in August 1986(560 cellsper liter;
1986(836 cellsper liter; 8.3 mg,/m3),
5.6 mg,/m3),and in October 1986(445 cellsper liter; 4.4 rng/m3).During
cold isothermal conditions, the numbers did not exceed200 cells per
liter. The lowest numbers were found in February and March 1987. In
the littoral zone 380 cells per liter and 3.8 mglm3 were observedin May
1987.
Askenasia chlorelligera n. sp.
Diagnosis, Size in vivo 30--40 x 2545 pm. Circumoral wreath of
granules roughly pentagonal.Macronucleus spheroidal to ellipsoid (3:
2). Two types ofpin-shaped extrusomes.Single contractile vacuole.
Type location. Excavatedgroundwaterponds near Graz (Styria, Austria).
Derivatio nominis. "chlorelligera" refersto the symbiotic greenalgae.
Description (Fig. 44-50,64-66; Table 1). Rostrum truncated,crownlike structure comprised of5-6 bumps apically, produced by protruding
bundles of shorter extrusome type. "Crown" resemblescross-sectionof
apple-core(Fig. 44, 48). Macronucleuswith sphericalchromatin bodies
of various sizes (Fig. 44, 64). Several specimenswith two spheroidal
fragments.Excretory canal ofcontractile vacuole about 2 pm long (Fig.
44). Short extrusomes about 10 pm, knobbed proximally, packed in
posteriorly slightly diverging, in cross-sectionelliptical bundles (Fig. 44,
45, 66). Long extrusomesabout I 8 pm, slightly curved, extending halfcell length posteriorly from crown, forming a basketin the center ofthe
cell (Fig. 44,66). Extrusome tips impregnated conspicuouslywith protargol (Fig. 65). Cytoplasm contains about 2G-30 Chlorella-algaeand
severalgreen algaeseeminglyin terms ofseveral characters,belonging
to Siderocelis(Fig. 44,66). Algae give the cell a grass-greencolor. Terminal vacuole discernible in vivo (Fig. aa). The EKB-kineties are
about one kinety width apart, basalbodiescomparatively loosely spaced
426
I99O
J. PROTOZOOL., VOL. 37, NO. 5, SEPTEMBER-OCTOBER
(Fig. 46, 49). The EKB-kineties have short trunks of 5-8 basal bodies
at the posterior end. The SKB-kineties interconnectby transversefibers
(Fig. 50). The posterior hemisphereshows polygonal, argyrophilic patteÄ 1EE. 50, 64). At the cell's equator there is a circumferential belt of
rectangularstructureslinking polygons with EKB-kineties (Fig. 50' 64).
The CWG comprises of paired granules of equal size, resembling a
haptorid oral dikinetid, encircling extmsome bumps (Fig. 49,65).
Occurrence and ecology. Very abundant in spring, reaching peak in
May 1986 (1,904 cells per liter; l4.l mglm3). In late fall relatively
abundant, smaller peak of 245 cells per liter and 1.8 mg,/m3occurred
in October 1986.Abundancescorrespondto O2-valuesof 10-14 mg per
liter and temperaturesbetween 8 C and 22 C.
Remarks. This is obviously the green, pelagicA. volvox which Kahl
[35] found in the plankton ofseveral freshwaterponds near Hamburg,
although already assuming it to be a new species(Fig. 47' 48).
Rhab do askenas ia n. gen.
Diagnosis. Mesodiniidae with circumoral kinety composed of dikinetids giving rise to nematodesmatawhich form a distinct basket(rhabdos). Kineties of equatorial and pre-equatorial belt composedof single
files ofbasal bodies, those ofsubequatorial belt composedoftwo basal
bodies each.
Type species. Rhabdoaskenasiaminima n. sp.
Derivatio nominis. The name refers to the distinct rhabdos and to
the similarity to Askenasia.Feminine gender.
Rhabdoaskenasit minima n. sP.
Diagnosis. Size in vivo 20-35 x 18-30 pm. Conical. Macronucleus
reniform. Two types of club-shapedextrusomes.Singlecontractile vacuole.
Type location. Excavatedgroundwaterponds near Graz (Styria, Austria).
Derivatio nominis. "minima" (lat. small) refers to the small size.
Description (Fig. 5l-55, 60-63; Table 1). Cell constricted at cell
equator and subapically at oral area, which has distinct centrally depressedbulge. Postequatorialportion globular, posterior pole with very
ihort knob. Single macronucleusin rear end of cell. Chromatin bodies
large,globular. Single,sphericalmicronucleus(Fig. 5 l). Contractile vacuol-esibequatorial, excretory canal about 2 pm in diameter. Anterior
extrusomes 8-9 pm long, arrayed around rhabdos, comprising clubshapedposterior part about 5 x I pm in size and needlelike, distally
curved anterior part about 3.5 pm in length (Fig. 51, 52, 63). Posterior
extrusomes7-8 pm long, scatteredin rear end, comprising slenderbatshapedposterior part about 5 x 0.5 pm in size and curved needlelike
ant;rioipart about 3 pm in length. Both types strongly reminiscent of
the extrusomesof Paraenchelyswenzeli,a haptorid genus [22]. Pellicle
firm resulting in fairly constant cell form, withstanding extendedcoverslip pressure.Cytoplasm pale g1een,sparselyfilled with lithosomelike inclusions. Bacteria (spirills) attachedto anterior portion (Fig. 5l).
No terminal vacuole observed.
The PKB-kineties with oblong basal bodies are associated with
obliquely oriented fibers (Fig. 54,60). The SKB-kineties are interconnected by transversefibers (Fig. 55, 61). Circumoral kinety composed
of paired, barren basal bodies of equal size. Curved transversefibers
originate from inner basal bodies, extending,radiallytoward cytostome
€iÄ. 52, 53, 60). Nematodesmata originate from outer basal bodies,
ioÄing distinct rhabdos extending to the cell's center (Fig. 52, 53,62\.
Occuirence and ecology. Relatively abundant in all seasons(l0G250 cells per liter) but culminating on October 21, 1986, with 2'67O
cells per liter and 9.3 mg/m3 at a depth of I m and 1,720 cells per liter
and 6.0 mglm3 at a depth of 3 m. Lowest numbers observedin December
1986and January 1987.
DISCUSSION
Classification of Askenasia. According to Corliss ll4l' Assubclass
kenasia belongs to the class Kinetofragminophora,
Gymnostomata, order Haptorida, family Didiniidae. Our investigations show that Askenasia lacks important haptorian
characteristics: the distinct rhabdos, the dorsal brush, and the
tightly meshed silverline system U4,26). Thus, we transfer -4skenasia to the order Cyclotrichida Jankowski, 1980, family Me-
sodiniidae Jankowski, 1980, whose key features readily match
those of ,4skenasia 126). However, the Cyclotrichida themselves
are in urgent need of investigation and revision under silver
impregnation techniques. The Cyclotrichida may possibly belong not to the subclass Haptoria but to another [26]'
Systematic position of Rhabdoaskenasia. Tt'e general plan of
R hab do aske nas i a is v ery similar to that of As ke n asi a. How ev er,
the distinct rhabdos and the single filed kineties ofthe equatorial
kinety belt indicate that this similarity might be only superficial,
resulting from convergent evolution. The rhabdos of Rhabdoaskenasia is in fact highly similar to that of many haptorids
122, 2 5, 261. However, Rh ab do aske nas i a lacks the dorsal brush,
which is the main character defining the members of the order
Haptorida 1261.Rhabdoaskenasia should therefore not be included in this order. It probably belongs to the order Pseudoholophryidae, as indicated by its extrusomes. However, the general organization is too close to that of Askenasla to justify such
a major shift without electron microscopic evidence'
Itlustrated key to the genera of the family Mesodiniidae (subThe following key (Fig.
class Haptoria, order Cyclotrichida).
67-7O) is based on the present results and on investigations by
other authors [9, 19, 30, 32,38, 45].
I Two equatorial kinety belts, equatorial belt (EKB) bearing "cirri"'
-... .. . 2
pre-equatorialbelt(PKB)bearingbristles
- Three equatorial kinety belts, equatorial belt (EKB) bearing sickle-shaped"cirri," pre-equatorial belt (PKB) bearing "pecti3
n e l l e s , s" u b e q u a t o r i a l b e l t ( S KbBe)a r i n g b r i s t l e.s. . . . . . . . . .
2 Anterior portion larger than posterior. The EKB-kineties are
composed of double rows of basal bodies arrangedin zigzagThe PKB-kineties comprise of groups of square-packedbasal
bodies. On apex distally forked tentacles,retractable.No contractile vacuole observed. Cytoplasm with permanent obligatory symbionts. Marine (Fig. 67)
. . Single speciesMyrionecta rubra (Lohmann, 1908)Jankowski,
r976
- Anterior portion smaller than posterior. The EK3-kineties with
double rows of basalbodies.The PKB-kineties with singlefiles
ofbasal bodies. Apically retractablestylets,distally with suckers. Contractile vacuole in rear end. Crescent-shapedterminal
vacuole. Severalfreshwaterand marine species(Fig. 68) ' . .
MesodiniumStein, 1862
3 Distinct rhabdos comprising nematodesmataoriginating from
circumoral kinety composed of dikinetids. The EKB-kineties
are composedof singlefiles of basal bodies. The SKB-kineties
are composed oftwo basal bodies. Freshwater(Fig. 69) . . . .
Single speciesRhabdoaskenasiaminima n- sp.
- Oral area encircled by circumoral wreath of paired granules
(CWG). Nematodesmatanot recognizable.The EK3-kineties
are composedof double rows of basal bodies arrangedinzigzag.The SKB-kinetiesare composedofthree basalbodieseach.
Several freshwaterand marine species(Fig. 70) . . .
A s k e n a s i a B l o c h m a1n8n9, 5
.......
ACKNOWLEDGMENTS
This study is part of a doctoral thesis undertaken at the University of Graz (Austria) and guided by Univ.-Doz. Dr. H. Sampl
and Univ.-Prof. Dr. R. Schuster. Their continuing interest in
our work is gratefully acknowledged. Special thanks also to Dr.
M. Knoflacher who made the equipment of the Joanneum Research Institute available to us. We would further like to thank
Mrs. Karin Bernatzky for her help with the photography.
LITERATURE
CITED
1. Alekperov,I. K. 1984. FreeJivinginfusoriaofKhachinchayresew oir. Hydrobiol. J., 20:17-22.
2. Aliev, A. R. 1982. On the fauna of infusoria microbenthos of
lakes Adzikabul and Nakhalykhchal. Izv. Akad. Nauka Azerb., year
1982:83-88.
KRAINER & FOISSNER_REYISION OF ASKENASIA
3. Bartsch, I. & Hartwig, E. 1984. Die bodenlebendeMikrofauna
im Hamburger Hafen. Arch. Hydrobiol., Suppl., 6l:543-586.
4. Bereczky,M. C. 1985. Fixations- und Färbeschnellverfahrenbei
quantitativen ökologischen {Jntersuchungen von Protozoen in BinArch. Protistenkd., 129:.187-19O.
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Received1-8-90; accepted5-23-90