European Journal of
PROTISTOLOGY
European Journal of Protistology 42(2006)269–279
Pseudovorticella zhengae n.sp.,P.dif?cilis (Kahl,1933)Jankowski,1976,and P.punctata (Dons,1918)Warren,1987,three marine peritrichous ciliates from north China
Daode Ji a,b,1,Weibo Song b,?,John Clamp c
a
School of Ocean,Yantai University,Yantai 264005,PR China
b
Laboratory of Protozoology,KLM,Ocean University of China,Qingdao 266003,PR China c
Department of Biology,North Carolina Central University,Durham,NC 27707,USA
Received 28April 2006;accepted 7July 2006
Abstract
The morphology,infraciliature and silverline system of three marine peritrichous ciliates,Pseudovorticella zhengae n.sp.,P.dif?cilis (Kahl,1933)Jankowski,1976and P.punctata (Dons,1918)Warren,1987,were investigated by observation in vivo and silver-staining methods.The new species is characterized by its body shape,the appearance of the peristomial lip,the number of transverse silverlines,and the con?guration of infundibular polykinety 3;P.dif?cilis by its body shape,the con?guration of infundibular polykinety 3,and unusual annular swellings on the stalk;and P.punctata by the appearance of the pellicle,the con?guration of infundibular polykinety 3,and the number of transverse silverlines.
r 2006Elsevier GmbH.All rights reserved.
Keywords:Marine ciliate;Morphology;Peritrichia;Vorticella ;Pseudovorticella zhengae n.sp.
Introduction
Identi?cation of Vorticella -like peritrich ciliates is usually complicated by a great similarity among species with respect to morphology of the living organism and insuf?cient description of known species (Ehrenberg 1831(1832);Kahl 1933,1935;Kent 1880–1882;Noland and Finley 1931;Stiller 1971;Warren 1986).Pseudo-vorticella is a relatively new genus of peritrichs formed
by taking some species with reticulate silverline systems from Vorticella (Foissner and Schiffmann 1974).The genus is frequently encountered in eutrophic water habitats,and with addition of 24species since its description,it now includes a total of 27species (Jankowski 1976;Ji et al.2003,2004,2005;Leitner and Foissner 1997;Song 1997;Song and Warren 2000;Song and Wilbert 1989;Sun et al.2005;Warren 1987).Unfortunately,over half of the species of Pseudovorti-cella are still dif?cult to identify owing to a lack of information about their infraciliatures and silverline systems.
Three species of Pseudovorticella were isolated during a survey of the ciliate fauna of the northeastern coast of China from 2002to 2004and investigated with silver-staining methods.After comparison with similar
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?Corresponding author.
E-mail address:wsong@https://www.doczj.com/doc/1e697953.html, (W.Song).
1
This paper is derived from a dissertation submitted in partial ful?llment of the requirements for the Doctor of Philosophy degree in the College of Life Sciences and Technology,Ocean University of China.
congeners,one of them was recognized as a species new to science,and the other two were identi?ed as known forms.Description of the new species and supplemental redescriptions of the other two are reported here. Materials and methods
Ciliates were sampled with a slide frame containing glass slides that were immersed in water at a depth of ca. 1m for10days.Two localities in or near Qingdao were sampled:a shrimp-farming pond and an abalone-farm-ing pond.
Ciliates were observed in vivo using an oil immersion objective and differential interference contrast micro-scopy.The infraciliature was revealed with protargol impregnation done according to Wilbert(1975),and the ‘‘wet’’silver nitrate method(Song and Wilbert1995) was used to demonstrate the silverline system.Termi-nology is mainly according to Warren(1986). Results
Description of Pseudovorticella zhengae n.sp.
Diagnosis:Marine species of Pseudovorticella with bell-shaped body,measuring40–80m m?60–100m m in vivo with?attened,thin-edged,laterally-projecting peristomial lip.Single contractile vacuole located ventrally.Macronucleus J-shaped.With29–34trans-verse pellicular striations from peristome to aboral trochal band and11–14from aboral trochal band to scopula.Three,closely-spaced,parallel rows of kineto-somes in infundibular polykinety3(P3);rows of P3 staggered at abstomal ends,with row1projecting farthest abstomally.
Type specimens:Type slides were deposited in the collection of the Natural History Museum,London,UK (NHM)(holotype,protargol preparation;No. 2005:3:24:6)and the collection of the Laboratory of Protozoology,Ocean University of China,Qingdao,PR China(LPOUC)(paratypes,protargol and silver nitrate preparations,respectively;Nos.020*******and 020*******).
Dedication:We are pleased to name this species after Professor Shouyi Zheng,an eminent protozoologist of the Institute of Oceanology,Chinese Academy of Sciences,in recognition of her great contribution to the taxonomy of foraminiferans.
Type locality:Shrimp-farming pond near Qingdao (361080N;1201430E),26July2002.
Habitat:Marine;water temperature251C,salinity 23%.
Morphology:Body hemispheroidal(Fig.1A–C). Length of body40–80m m in vivo,maximum width (60–100m m)at peristomial lip,with length-to-width ratio of0.6–0.8(Table1).Peristomial lip noticeably thin (2–3m m in thickness),?attened,?exible,projecting laterally to form a shelf(Figs1A and2A,B).Border of peristomial lip irregularly serrated when peristome everted(Fig.2E),folded into frill-like pleats when contracted(Fig.2C).Peristomial disc?at,slightly elevated above peristomial lip(Fig.1A–C).Pellicle appearing smooth at low magni?cation,but reticulate pellicular alveoli are clearly visible above magni?cation of400?.
Cytoplasm slightly refractile,usually containing a few to many food vacuoles(Figs1A and2B).Single contractile vacuole ventrally located(Fig.1A).Macro-nucleus elongate,cylindroid,J-shaped:oral section transversely oriented and located at1distance from peristome to scopula,surrounding oral end of infundi-bulum;aboral section extending to aboral end of body, recurved orally(Fig.1A).Micronucleus not observed. Stalk measuring350–550m m in length,5–6m m in diameter when extended,with smooth outer surface (Fig.2A and F).Spasmoneme within stalk1.5–2m m in diameter,with numerous,conspicuous,dark gray, thecoplasmic granules(mitochondria)measuring ap-proximately0.8m m in diameter lying just beneath cell membrane(Fig.2F).Telotroch(swarmer)cylindrical, measuring approximately55m m?40m m(Fig.2D). Oral infraciliature as shown in Figs1D,E and3A–C. Haplokinety(H)and polykinety(Po)make one and one-third turns together around peristome before entering infundibulum,where they make a further turn on opposite walls.Epistomial membrane located near opening of infundibulum as commonly seen in other peritrichs(arrows in Figs1E and3A).Germinal kinety (G)running parallel to H in abstomal half of infundibulum.Infundibular part of Po,namely infun-dibular polykinety1(P1),consisting of three rows of kinetosomes and accompanied by two additional infundibular polykineties(P2,P3),each consisting of three rows of kinetosomes.Infundibular polykinety1 and P2much longer than P3.Rows of P1approximately equal in length,terminating at infundibulum-cytostome boundary.All rows of P2ending together far abstomally from cytostome at curvature of P1;P2separated from P1by wide gap.Rows of P3closely spaced and ending abstomally in staggered fashion,with row1(nearest to P2)longest and row3(farthest from P2)shortest (Fig.1D).Somatic infraciliature consisting of aboral trochal band composed of?ne,zigzag row of kineto-somes encircling body at2
3
distance from peristome to scopula(Fig.3C,arrowheads).
Pattern of silverline system reticulate,with sparsely distributed pellicular pores(Fig.3D).Number of transverse silverlines from peristome to aboral trochal band29–34,from aboral trochal band to scopula11–14 (Table1).
D.Ji et al./European Journal of Protistology42(2006)269–279 270
Redescription of Pseudovorticella dif?cilis(Kahl, 1933)Jankowski,1976
Emended diagnosis:Marine species of Pseudovorticella with elongate,bell-shaped body,measuring50–70m m?35–45m m in vivo.Single contractile vacuole located dorsally.Macronucleus J-shaped.With33–40transverse pellicular striations from peristome to aboral trochal band and15–17from aboral trochal band to scopula. Infundibular polykinety3composed of three rows of kinetosomes;row1shorter than others,with proximal end further from cytostome.
Fig.1.Morphology of Pseudovorticella zhengae n.sp.and similar species.(A)Typical zooid at high magni?cation.(B,C)Variability of body shape.(D)Infundibular part of oral infraciliature.(E)Entire oral infraciliature;arrow marks the epistomial membrane.(F) Pseudovorticella paracratera(from Ji et al.2004).(G)P.patellina(from Song and Warren2000).(H)Vorticella fornicata(from Song 1991).(I)V.cratera(from Ji et al.2004;after Kent1880–1882).Abbreviations:G,germinal kinety;H,haplokinety;P1–P3, infundibular polykineties(arrow with numbers shows convention for numbering rows within each polykinety);Po,peristomial polykinety.Scale bars30m m(A,F–H);100m m(I).
Table1.Morphometric characters of three species of Pseudovorticella
P.zhengae P.dif?cilis P.punctata Body length in vivo(m m)56.0713.058.074.747.474.3
44–80;n?652–64;n?840–54;n?7 Body width in vivo(m m)76.0714.441.572.349.876.5
60–100;n?638–44;n?845–62;n?6 Number of silver lines from peristome to aboral trochal band3172363373
29–34;n?1233–40;n?430–37;n?11 Number of silver lines from trochal band to scopula1371161872
11–14;n?815–17;n?415–20;n?9 For each character,mean and standard deviation are on the?rst line,range and number in sample are on the second line.
D.Ji et al./European Journal of Protistology42(2006)269–279271
Locality and habitat :Abalone-farming pond on the coast of Qingdao,19June 2003.Marine,water temperature 19.51C,salinity approximately 30%.
Voucher slides :Slides of representative material were deposited at the NHM,London (protargol preparation;No.2005:3:24:3)and the LPOUC (silver nitrate and protargol preparations;Nos.0306190101and 0306190102).
Morphology :Body elongate,bell-shaped (Figs 4A,B,E–G and 5A,B ),measuring 50–70m m ?35–45m m in vivo with length-to-width ratio of 1.2–1.5(Table 1),constricted aboral of peristomial lip;maximum width of cell usually at mid-body but sometimes at oral area.Peristomial lip moderately thick,wide,and projecting;peristomial disc moderately elevated above peristomial lip (Figs 4B and 5B ).Pellicle smooth,striations only visible at 1000?magni?cation (Fig.5C ).
Cytoplasm transparent or slightly refractile;some well-fed zooids packed with many brown or yellowish food granules (Figs 4A,B and 5A–C ).Single contractile vacuole located dorsally (Fig.4B ).Macronucleus cylindroid,vermiform,J-shaped in lateral view:oral section transversely oriented,surrounding oral end of infundibulum;aboral section extending to aboral end of body,recurved orally (Fig.4B ).
Stalk measuring 150–280m m in length and 5–6m m in diameter when extended,with smooth outer surface.Two or three dense,narrow,annular swellings always visible on stalk at intervals of 50–80m m (Figs 4A and 5A,B,D,E ).Spasmoneme 2m m in diameter,with thecoplasmic granules (mitochondria)measuring 0.5m m in diameter sparsely distributed beneath cell membrane (Fig.5D ).
Oral infraciliature (Figs 4C,D and 5F,G )similar to that of congeners.Haplokinety and Po closely parallel,making one and one-third turns together around peristome,making one further turn around opposite walls of infundibulum.Infundibular polykinety 1and P2
Fig.2.Photomicrographs of Pseudovorticella zhengae n.sp.from life.(A )Zooid at low magni?cation.(B )Zooid at 200?magni?cation.(C )Apical view of zooid at high magni?cation to show the contracted peristomial lip.(D )Apical view of a telotroch.(E )Lateral view of zooid at 400?magi?cation,to show irregular serrated peristomial lip.(F )Structure of stalk.Scale bars 200m m (A);50m m (B,E);40m m (D);10m m (F).
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as in P.zhengae.Infundibular polykinety3consisting of three rows of kinetosomes.Row1of P3(nearest P2) only half as long as other two rows,separated slightly from them,terminating adstomally with P2far short of infundibulum-cytostome boundary(Figs4C,D and5F). Rows2and3of P3closely parallel for entire length except for small separation at midpoints,terminating with P1at cytostome(Fig.4C).Aboral trochal band composed of zigzag row of kinetosomes encircling body
at3
4distance from peristome to scopula.
Silverline system reticulate,with numerous pellicular pores distributed evenly(Fig.5H).Number of trans-verse silverlines between peristome and aboral trochal band33–40,from aboral trochal band to scopula15–17.
Redescription of Pseudovorticella punctata(Dons, 1918)Warren,1987
Emended diagnosis:Marine Pseudovorticella with bell-shaped body,measuring40–55m m?45–65m m in vivo, with tuberculate pellicle.Single contractile vacuole located ventrally.Macronucleus J-shaped.With30–37 transverse pellicular striations from peristome to aboral trochal band and15–20from aboral trochal band to scopula.Infundibular polykinety3composed of two
Fig.3.Photomicrographs of Pseudovorticella zhengae n.sp.after staining with protargol(A–C)and silver nitrate(D).(A) Epistomial membrane(arrow);(B)Infundibular part of oral infraciliature.(C)Abstomal end of P2(arrow);aboral trochal band (arrowheads).(D)Silverline system.Abbreviations:P1–P3,infundibular polykineties1–3.
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rows of kinetosomes;row 1shorter than the other,terminating far abstomally of cytostome.
Locality and habitat :Abalone-farming pond on the coast of Qingdao,22May 2002.Marine,water temperature 181C,salinity 31%.Voucher slides :Slides of representative material were deposited at the NHM,London (protargol prepara-tion;No.2005:3:24:5)and the LPOUC (silver nitrate and protargol preparations;Nos.0405210101and 0405210102).
Fig.4.Morphology of Pseudovorticella dif?cilis .(A )Zooids at low magni?cation.(B )Typical zooid at high magni?cation.(C )Infundibular part of oral infraciliature.(D )Entire oral infraciliature;arrow marks the epistomial membrane.(E–G )After Kahl (1935).Abbreviations:G,germinal kinety;H,haplokinety;P1–P3,infundibular polykineties 1–3;Po,peristomial polykinety.Scale bars 150m m (A);25m m (B).
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Morphology:Expanded individuals bell-shaped to conoid(Figs6A–F and7A–D).Body40–55m m long, widest at everted peristomial lip,measuring45–65m m wide at this point,with length-to-width ratio of0.8–1.0 (Table1).Peristomial disc?at,slightly elevated above peristomial lip(Fig.6A).Constriction of body usually
visible at2
3distance from peristome to scopula at point
where aboral trochal band is located(Fig.6A). Reticulate pellicular striations distinctly visible at 100?magni?cation;pellicular alveoli convex,creating tuberculate surface.
Macronucleus cylindroid,vermiform;usually J-shaped in lateral view,with aboral section extending to aboral end of body and recurving(Fig.6A)but sometimes C-shaped and transversely oriented,with aboral section missing(Fig.6B and C).Single contractile vacuole
located ventrally at1
4body length from the peristome
(Figs6A and7D).Cytoplasm transparent,colorless at poles of body,shading to yellowish in middle part of body owing to presence of numerous tiny granules and food vacuoles(Fig.7B and D).
Stalk with smooth surface,measuring150–280m m in length and5–6m m in diameter when extended.Spasmo-neme2–2.5m m in diameter,with string of dark thecoplasmic granules(mitochondria)measuring 0.8m m in diameter beneath cell membrane.
Oral infraciliature(Figs6I and7E,F)similar to that of congeners.Haplokinety and Po closely parallel, making one and one-half turns together around peristome,making one further turn around opposite walls of infundibulum.Infundibular polykinety1and P2 as in congeners.P3consisting of two rows of kineto-somes,with row1(nearest P2)only half as long as row 2,terminating adstomally with P2far short of infundi-bulum-cytostome boundary.Row2of P3extending to cytostome,terminating adstomally at same point as rows of P1.Somatic infraciliature consisting of aboral trochal band of kinetosomes encircling cell at3
4
distance from peristome to scopula(Fig.7G,arrows)and visible in silver nitrate preparations as2–3closely spaced,intensely staining,transverse silverlines (Fig.7I,arrows).
Fig.5.Photomicrographs of Pseudovorticella dif?cilis from life(A–E)and after staining with protargol(F,G)and silver nitrate(H). (A,B)Zooids at low magni?cation,arrow in A indicates annular swelling of stalk.(C)Zooid at high magni?cation to show pellicular striations and food vacuoles.(D,E)Stalk at high magni?cation to show mitochondria(dark granules in spasmoneme)and annular swelling on stalk(arrow).(F)Infundibular part of oral infraciliature.(G)Peristomial part of oral infraciliature to show the epistomial membrane(arrow).(H)Silverline system.Abbreviations:P1–P3,infundibular polykineties1–3.Scale bars100m m(A,B); 20m m(C);10m m(D).
D.Ji et al./European Journal of Protistology42(2006)269–279275
Silverline system reticulate,with sparsely distributed pellicular pores (Fig.7I ).Number of transverse silver-lines between peristomial area and aboral trochal band 30–37,from aboral trochal band to scopula 15–20.
Discussion
Comparison of Pseudovorticella zhengae n.sp.to similar congeners
Commonly accepted criteria for species identi?cation in the genus Pseudovorticella include body shape and size,number and location of contractile vacuoles,oral
morphology and infraciliature (especially that of P3),and features of the silverline system (Foissner 1979;Foissner and Schiffmann 1974;Ji et al.2004;Warren 1987).Pseudovorticella zhengae can be easily recognized by its thin and distinctly projecting peristomial lip and distinctive arrangement of rows in P3;however,a few species still should be compared with it owing to some similarity in gross morphology of the living organisms.Pseudovorticella paracratera Ji et al.,2004bears a strong resemblance to P.zhengae in terms of body shape,size,and habitat;however,the former has densely arranged tubercles on the peristomial lip (vs.irregularly serrated but without distinct tubercles in P.zhengae )
Fig.6.Pseudovorticella punctata (A–F,I)and similar morphotypes (G–H).(A )A typical zooid at high magni?cation.(B,C )Variability of body shape.(D–F )From Dons (1918).(G )Pseudovorticella quadrata (from Foissner,1979).(H )P.sphagni (from Foissner,1979).(I )Peristomial infraciliature;arrow marks the epistomial membrane.G,germinal kinety;H,haplokinety;P1,3,infundibular polykineties 1,3;Po,polykinety.Scale bars 25m m.
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and two contractile vacuoles(vs.one)(Fig.1F).The infundibular infraciliature of P.paracratera is markedly different from that of P.zhengae.The former species has a P3in which row1ends adstomally at the same point as the rows of P2,as also does in P.dif?cilis,P.punctata and P.sinensis(Figs4C–D and6I;Ji et al.2003,2004).By contrast,row1in the P3of P.zhengae extends far beyond P2and ends adstomally at the same point as the rows of P1and the other two rows of P3(Fig.1D and E).
Pseudovorticella zhengae is also similar to the well-known form,Pseudovorticella patellina(Mu ller,1776) Song and Warren,2000,but it can be recognized clearly as distinct from it because it has only one contractile vacuole(vs.2in P.patellina)and more transverse striations from the peristome to the aboral trochal band (29–34vs.19–22)(Fig.1G,Song and Warren2000).The infundibular infraciliature of P.zhengae shows some similarity to that of P.patellina;however,the P3of the
Fig.7.Photomicrographs of Pseudovorticella punctata from life(A–D)and after staining with protargol(E–H)and silver nitrate(I).
(A)Zooids at low magni?cation.(B–D)Zooids at higher magni?cation to show contractile vacuole(arrow)and variability of body shape.(E)Apical view of peristomial infraciliature to show the epistomial membrane(arrow).(F)Infundibular part of oral infraciliature.(G)Aboral trochal band(arrows).(H)Forming telotroch to show myoneme system and aboral trochal band in expanded form(arrows).(I)Silverline system;arrows indicate the aboral trochal band.Abbreviations:P1–P3,infundibular polykineties1–3.Scale bars100m m(A);40m m(B,C);30m m(D).
D.Ji et al./European Journal of Protistology42(2006)269–279277
latter species extends adstomally well beyond the end of P1(Song and Warren2000)instead of ending at the same point as P1(Fig.1D–E).
Two species of Vorticella in which the silverline system and,thus,generic identity remain unknown, should be compared to P.zhengae because of their similarity to it:Vorticella cratera Kent,1881(Fig.1I) and V.fornicata Dons,1915(Fig.1H).The peristomial lip of Vorticella cratera is very similar to that of P.zhengae;nevertheless,it can be distinguished from the new species by its freshwater habitat(vs.marine) and much greater body length(120–130vs.40–80m m) (Kent1880–1882).Likewise,V.fornicata is much smaller(24–32m m?24–37m m vs.40–80m m?60–100m m) than P.zhengae(Song1991).
Remarks on Pseudovorticella dif?cilis
The population of P.dif?cilis that we sampled is closely similar to the original description in all known characters(i.e.,body shape and size,number and position of contractile vacuoles,and habitat;Kahl 1933),making identi?cation quite certain.The annular swellings of the stalk of this species are a signi?cant characteristic that appears to be unique within the genus.
Foissner and Schiffmann(1974)reported a freshwater vorticellid to which they gave the name Pseudovorticella dif?cilis var.magnistriata.The freshwater form has a considerably larger body size(60–140vs.50–70m m)and fewer transverse silverlines(25–31vs.33–40)compared to both the Chinese population and the original description.Accordingly,we consider it should be a separate species from P.dif?cilis.
Comparison of Pseudovorticella punctata to similar congeners
According to the original description(Dons1918), P.punctata is characterized mostly by its body shape and size,number and location of contractile vacuoles, and appearance of its pellicle,all of which correspond well to the species that we observed.Pseudovorticella quadrata Foissner,1979(Fig.6G)resembles P.punctata in number of silverlines and location of the contractile vacuole(Foissner1979);however,the former differs from the latter with respect to the habitat(freshwater vs. marine),body length(40–55vs.65–80m m)and shape of the body(barrel-shaped vs.bell-shaped)(Fig.6A–C,G; Foissner1979).Also,the peristomial lip is more prominent in P.punctata than in P.quadrata,and there is a noticeable constriction below the peristomial lip of the former that is lacking in the latter.Morphologically, Pseudovorticella sphagni Foissner and Schiffmann,1974 (Fig.6H)also resembles P.punctata,but is distinguished from it by having two contractile vacuoles(vs.one in P.punctata)and far fewer silverlines between the aboral trochal band and the scopula(8–10vs.15–20)(Foissner 1979).
Acknowledgments
This work was supported by the‘‘Natural Science Foundation of China’’(project number:30430090)and ‘‘Doctoral Starting Foundation of Yantai University’’(project number:HX05B19).Thanks are also given to Dr.Xiaofeng Lin,for collecting some samples. References
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