Bulletin of Zoological Nomenclature 59(3) September 2002 165

Neotypification of protists, especially ciliates (Protozoa, Ciliophora)

Wilhelm Foissner

Llniversität Salzburg, Institut für Zoolog ie, H e I lbrunners t rasse 3 4,A-5020 Salzburg, Austria

Abstract. Historically, most soft-bodied species of heterotrophic protists (Protozoa)have been difficult to preserve and consequently lack type material that can bere-investigated. This causes taxonomic and nomenclatural problems and increasesthe degree of subjectivity in the identification ol these organisms. There are hardlyany ciliate species whose identity has not been queried, or will be disputed as newdata become available. However, recently methods have been developed that allowciliates (Ciliophora) to be preserved in a way that allows type material to be preservedand re-examined. The current paper proposes that ciliate species are accuratelyre-described and neotypes designated that can be preserved using the new methods.The paper also proposes that the Commission should consider waiving Article 75.3.6of the Fourth Edition of the International Code of Zoological Nomenclature (1999)in relation to ciliates and other groups of protists and small Metazoa. This Articlestates that neotypes should be designated from specimens that come as near as

practicable from the original type locality. The reasons why the Article should bewaived lor these organisms are discussed.

Keywords. Nomenclature; taxonomy; Protozoa; Ciliophora; protists; ciliates;neotypification; type locality.

Introduction

This paper aims to stimulate discussion about the absence ol or inadequate qualityof type material lor protists, especially ciliates (Protozoa, Ciliophora). To date, thisimportar-rt problen-r has been largely ignored by the scientists concerned and by thescientific community in ger-reral. The lack of interest in protist nomenclaturalproblems is illustrated by the low number of relevant cases published in the Bulletino.f Zoologicul Nomenclature and an ignorance olthe International Code of ZoologicalNomenclature displayed in recent publications by protozoologists. There areprobably two main reasons lor this: (i) there are very few people studying theseminute organisms and even f-ewer are interested in their alpha-taxonomy ar-rd

nomenclature, and (ii) there is a lack of type material, which causes nomenclaturalproblems and leaves identification extremely subjective. Similar problems exist inmost 'microfaunal' groups and even more severely in the nematodes (Nematoda).

lnadequate type material .

The lack ol type material is the result ol l"ristorical problems with the preservationoI ciliate specimens and rnore than 90'Yu of all described ciliates lack type material.Where it does exist, species are often represented by rnaterial that fails to sl'row thediagnostic f-eatures. Further, in some cases material is dilhcult to obtain because it is

deposited in private collections (see Foissner & Pfister, 1997).

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166 Bulletin ol'Zoological Nomenclaturc 59(3) Septcnrbcr 2002

The lack of type material is one of the most dimcult problems lacing proto-zoologists involved in ciliate or other protozoan alpha-taxonomy. There areir.rnumerable examples ol poorly described species, doubtlul identifications, andproblematic redescriptions. Although n-ry own research group may recognize a

tlrorough redescription as 'authoritative', others rnay not. Berger (1999),lor example,assigned Onychodrontopsis fiexili.s Stokes, 1887, accurately redescribed and neo-typified by Petz & Foissner (1996), to Allotricha, a genus and species which has neverbeen illustrated or accurately described. Obviously, in the absence of reliabie typematerial, no consensus can be reached and ciliate identification and nomenclaturemust remain a matter of choice.

Improved methods for preserving ciliatesAt present, most 'modern' ciliate types are deposited at two centres: the

Smithsonian Institution in the U.S.A. (Corliss, 1972;- Cole, 1994) and the BiologyCenter olthe Museum of Upper Austria in Linz (Aescht, 1994). In the last 30 years,protozoologists have developed improved methods for preserving these soft-bodiedorganisms, allowing reliable type material to be obtained and preserved. Specimensare impregnated with silver nitrate and/or protargol to show the arrangement ofsomatic and oral cilia (known as infraciliature or the silverline system), which areamong the most important features in ciliate alpha-taxonomy (Foissner, 1991).

Under certain circumstances other methods such as the Feulger-r reaction are used toexamine tl.re main leatures in the nuclear apparatlrs.

Usually, light- and/or electron-microscopical micrographs and molecular dataalone ale not sufficient lor description ol species, but may add important additionaldata to the inlormation available from conventional (silver) preparations. Themethods needed will depend on the group of protists under consideration. What is

irnportant is that the feature(s) mentioned in the description can be seen in thedesignated type material. Often several 'holotype specimens' might be necessarybecause not all I'eatures can be seen in a single specimen or preparation. Here, tl'reconcept of the hapantotypes can be applied (Article 73.3).

A solution to taxonomic and nomenclatural difficulties in the ciliatesMany protist taxonomic and nomenclatural problems could be solved by the

provision ol type material using the new methods mentioned above. Tl.re presentpractice of using illustrations as holotypes does not solve the underlying problen'tbecause these illustrations often cannot be examined to reveal new data when anexisting description is for"rnd to be incomplete or inaccurate. Fr-rrther, leatures whichare consiclered as unimportant at the time of description may later become decisivetaxononric characters lor comparison with new specics. Neotypification is the oneway to overcome these and related problems and to bring stability in ciliatelaxononry and identification. This was emphasized by Corliss (1912), who establishedsome ncotypes lor'difficult'ciliates in the sixties. Likewise, Medioli & Scott (1985)

established neotypes fbr some testate amocbae.Gencrally, however, neotypification has not been practised widely in the protists.

It was only recer.rtly tl-rat rny own research group adopted this valuable approach toclarilying protist laxonomy and nomenclature (Foissner, 1997, 1999b; Foissner &Brozck, 1996; Foissner & Dragesco, 1996; Foissr.rer & Krer,rtz, 1996:Petz & Foissner,

Bullctin of Zoological Nomenclature 59(3) Scpternber 2002 161

1996). However, it is a practice that several specialists have since lollowed (Agatha &Riedel-Lorj6, 1998; Petz et al., 1995; Song et al., 2001).

Neotypification is especially uselul when:(1) no type material is available (holotype specimen and hapantotypes; see Article

73.3), but identification of the taxon is comparatively straightlorward,(2) type material is available, but too poorly preserved for the diagnostic

features to be recognizable. This situation may need to be relerred to the

Comrnission;(3) the original description is so incomplete and/or based on so few specimens that

any identification becomes a matter of arbitrary judgement. Alternatively, such

descriptions could be considered as referring to species indeterminate. How-ever, this would greatly increase the number of scientific names because manyoriginai descriptions of ciliates are very incomplete. We prefer, where possible,to identily our taxa in relation to previously described species, and to redefinethese species by detailed redescriptions. We ensure that the redescription is

based on material which shares at least one main distinctive leature ol the

original material;(4) it has been argued that the species has one or more subjective synonyms. This

indicates that the taxon has a questionable identity in the literature and, in theabsence of type materiai, creates a 'classical' justification for neotypification,

(5) there are several similar species whose identity wili be fully differentiated byneotypification;

(6) there are cornpeting redescriptions for a taxon.

Article 75 of the CodeMost olthe neotypes that my group has designated are in accordar-rce with Article

75 of the Code. However, as protists lorm restirrg cysts, have a wide geograpl-rical

distribution, and olten lack any type material (Corliss, 1993), it is sometimes difficultto designate neotypes that lully satisly Article 75. L-r some cases our ciliate neotypedesignations do not comply with Article 75.3.6 as they were not collected from ornear the type locality. As such, thcse and similar neotypifications could be considered

to be invalid. However, we do not consider Article 75.3.6 to be relevant to protistneorypes lol the following reasons:

(1) most ciliates and protists are cosmopolitan, at lerist at the morphospecies level

(Finlay et al., 1996; Foissner, 1999a). In addition, many are syn'rbionts,

commensals, or parasites ol metazoan animals that often have a n-ruch widcrbiogeographical distribution than the narrow dehnition of 'type locality'implies;

(2) the existing uncertainties can be overcome only by making types r-rniversally

available to protozoologists. The improvemellts in protist taxonomy thatneotypification produces fär outweigh the possible danger ol misidentilledne otypes that czrn occur lrom specimens selected out ol original typclocality;

(3) as there are only a lew alpha-taxor.romists working with ciliates, it is

difficLrlt for them to obtain neotype material lrom or near the type locality.The application of Article 75.3.6 could prcvent neotypes lronr evcr bcing

designated;

t6E Bulletin ol' Zoological Nomcnclature 59(3) Septcmber 2002

(4) the likelihood of re-discovering ciliates and other protists at a certain localityis not guaranteed because the organisms may be in a dormant (cystic) stage lormost of their life and laboratory cultivation is often unsuccessful.

ConclusionTo sum up, I suggest that neotypes ol protists, especially ciliates, should be freed

lrom the type locality regulation of Article 15.3.6 of the Code, provided thatneotypiflcation is based on a thorough redescription of the organism and usable

neotype material has been deposited in an acknowledged repository. In addition,existing neotypes that have already been designated lrom other than original typelocalities should be validated by the Comrnission.

AcknowledgementsI thank David Patterson (Australia), Michael Dolan, John Corliss, Neil Evenhuis

(U.S.A.) and Andrew Wakeham-Dawson (Commission Secretariat, London) forhelpful comments on an earlier dralt of this paper.

References

Aescht, E. 1994. Die Erlorschung der Urtiere (Protozoen) in Österreich. Kataloga de.s

Oberö.vterreichischen Lande.stnuseunts, Naue F-olge, 7l: 1'79.Agatha, S. & Riedel-Lorj6, J.C. 1998. Morphology, inflraciliature, and ecology ol some

strobilidiine ciliates (Ciliophora, Oügotricl'rea) from coastal brackish water basins olGermany. Europeun Journol of Prati.ttologl'. 34: 10 17.

Berger, H. 1999. Monogruph o.f the O-t))tri('hidue (Ciliophoru, Hypotrichiu).1080 pp. Klur.ver.

Dordrecht, Boston, London.Cole, L. 1994. Catalog ol type specimens in the international protozoan type collection.

Sntitltsoniat Contributions to Zttoktgt,,56l: I 28.Corliss, J.O. 1912. Current status of the international colleclion of ciliate type-specimens and

guidelines lor hrture contributors. Trtur.yuttions o.f tlte Atneric'crn Mict ostopitrtl Societr,9l221 )_35.

Corliss, J.O. 1993. Should there be a separate codeBfuSy.stent.t,28: | 14.

Finlay,8.J., Corliss, J.O., Esteban, G. & Fenchel, T. 1996

the number of lree-living ciliates in the biosphere.

of nomenclature for the protists')

. Biodiversity at the microbial level:

Quurtcrll, Rat,iatr o.f' Birtlot.t,. 7l'22t 231.

Foissner, W. 1991. Basic light and scanning electron nricroscopic mcthods for taxortomicstudies of ciliated protozoa. Europctttt Jottrnul o.f Protis'lologl',27: 3ll 330.

Foissner, W. 1997. Faunistic and laxonomic studies on ciliates (Protozoa, Ciiliophora) fronrclean rivcrs in Bavaria (Germany), with descriptions of new species and ecological I'rotes.

Linrrrologicu, 27. 119 238.Foissner, W. 1999a. Protist diversity: estin-ratcs ol' the near-imponderable. Prr.rrr.it, 150:

363 368.Foissner, W. 1999b. Notes on the soil ciliate biota (Protozoa, Ciliophora) lrorn the Shimba

Hills in Kenya (Africa): diversity and description oltl.rree new genera and ten ncw species.

Biodivcr.rity und Conservaliort, 8: 319 189

Foissner, W., Agatha, S. & Berger, H.2002. Soil ciliates (Protozoa, Ciliophora) from Namibia(Southwest Alrica), with emphasis on two contrasting cnvironments, the Etosha regiortarrd the Namib Desert. Deni.viu (Lin-).5: I 1490.

Foissner, !V. & Brozek, S. 1996. Taxonomic characterization of Psezrrlrthuplotuulu.s irtfiu-t,rrct«tltttus nov. spec. and Vrtrtit'clltt cltlorallutu Stillcr 1940, epiplanktonic periLricits(Ciliophora. Poritrichia) attachecl to coerrobia ol' Anultucnu (Cyanophyta), including a

Bulletin of Zoological Nornenclature 59(3) Septenrbcr 2002 169

redescription of V. chbro.stignta (Ehrenberg, l83l). Internutk;nula Rame der gesontten

Hydrobiologic, 8l: 329-351.Foissner, W. & Dragesco, J. 1996. Updating the trachelocercids (Ciliophora, Karyorelictea).

III. Redefinition of the genera Truchelocertu Ehrenberg and Tracheloroplti.s Dragesco,an«J evolution in trachelocercid ciliates. Archiv/ür Protistenkurule, 147:43 9l .

Foissner' w' & Kreutz' M' 1996' Redescription ol Platyophrvu spltugtti (Penard 1922) Foissner

I 993 (Protozoa, Ciliophora). Lin:er bioIogische Beit rüge, 28: 7 45-7 56.

Foissner, W. & Pfister, G: 1997. Taxonomic and ecologic revision ol urotrichs (Ciliophora,Prostomatida) with three or more caudal cilia, including a user-friendly key. Limnologica,27: 3ll-347.

Medioli, F.S. & Scott, D.B. 1985. Designation ol rypes, lor one genus and nine species olarcellaceans (thecamoebians), with additional original relerence material lor lour other

species. Journal of Foraminiferal Re.search, 15 24-37.Petz, iV. & Foissner, W. 1996. Morphology and morphogenesis of Lrarr tost),lo edaphoni Berger

and Foissner and Onyclndrontop.sisfiexilrs Stokes, two hypotrichs (Protozoa: Ciliophora)from Antarctic soils. Acta Protozoologica,35 257 280-

Petz, W., Song, W. & Wilbert, N. 1995. Taxonomy and ecology of the ciliate launa (Protozoa,

Ciliophora) in the endopagial and pelagiat olthe Weddell Sea, Antarctica. Stapfo (Lin:),40: I 223.

Song, W., Petz, W. & Warren, A. 2001. Morphology and morphogenesis ol the poorly-knownmarine urostytid ciliate, Metaurostylopsis marina (Kahl, 1932) nov. gen., nov. comb.

(Protozoa, Ciliophora, Hypotrichida). European Journal of Pro t is tol ogy, 37 : 63-7 6.

Commenrs on this article are invited lor publication (subject to editing) in the Bulletin; they

shoul<i be sent to the Executive Secretary, I.C.Z.N., c/o The Natural History Museum,

Cromwell Road. London SW7 5BD, U.K. (e-mail: iczn@nhm.ac.uk).

Figs. I .3. T'wq ol'several ciliate spccies neotypificd in Foissner et al. (2002). l, 2: Ventral views of Metopus

grD.-bri,i Kahl. 1927 in vivo and at'ter protargoI silver impregnation. This species was errot.tcously

synonynrizccl will'r M. .striutu.r McMurrich, 1884 in a recent rovision. l: Silver nitrate impregnatecl specimen

it' ptitrl,,pttr.ridt,.s lutu.: (Kahl. 1930). a specie s with a complicatetl taxononric history settled by

neotypilica t ion.

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