Problems in the Nomenclature of Higher Taxonomic Categories

13 Pages·1991·3.9 MB·

by  Ya I Starobogatov

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6 BulletinofZoologicalNomenclature48(1)March199
ProblemsintheNomenclatureofHigherTaxonomic Categories
Ya. I. Starobogatov
ZoologicalInstitute AcademyofSciencesofthe U.S.S.R., Universitetskaya
,
naberezhnaya 1, 199034Leningrad V-34, U.S.S.R.
TranslatedbyMarkJ. Grygier
SesokoMarineScience Center, UniversityoftheRyukyus, Sesoko,
Motobu-cho, Okinawa905-02,Japan
(currentaddress: 14804NotleyRoad, SilverSpring, Maryland20905 U.S.A.)
,
Translator'snote.Thisarticlefirstappearedin 1984(seereferences)andthetranslation
ispublishedwiththepermissionoftheauthorandofIzdatel'stvoNauka,thepubHsher
oftheRussianoriginal.
Dr Starobogatov is a noted Soviet zoologist, a widely respected malacologist and
theoreticalphylogenist,andamemberoftheInternationalCommissiononZoological
Nomenclature. Since thefirst publication in Russian ofDrStarobogatov'sproposals
forthegradualintroductionofregulationofthenomenclatureoftaxonomiccategories
higherthansuperfamily,hehasappliedtheseproposalshimselfinseveralpublications
concerning various groups of arthropods. His revision of the classification of the
Crustacea(Starobogatov, 1986),forexample,reachedabroadaudienceafteritstrans-
lation into EngUsh (Starobogatov, 1988). I believe that a republication in English of
thereasoningandtheformalproposalsthatliebehindhiscontroversialnomenclatural
revisionsisnecessaryandoverdue.Someslightalterationsandabridgementshavebeen
made in the text, with Dr Starobogatov's approval, in order to clarify and update
certainpassages.
Afewyearsago,inthepagesofPaleontologicheskiyZhurnal,apaperbyRohdendorf
(1977) appeared that was devoted to the problem of the nomenclature of higher
taxa. [Thispaperwasreproducedin EngHshin Rasnitsyn's(1982)proposal toextend
the provisions of the Code to taxa above the family-group (BZN 39: 200-207)].
Rohdendorfwasnotonlyaverywellknown Sovietpaleontologist andentomologist,
butalsoagreatspecialistonproblemsofzoologicalnomenclature(herepresentedthe
U.S.S.R. on the International Commission ofZoological Nomenclature). It is more
ofteninpaleontologicalstudiesthattheneedarisestoreviselargetaxa,andinconnec-
tionwiththis,quesdonsariseabouttheselectionofsuitablenamesforthem.Zoologists,
especiallythosestudyinggroupswithastablesystemthathasbeenworkedoutindetail
(forexample,vertebratezoologists),areratherlessbotheredbythesequestions,zool-
ogistswhostudypoorlyworkedoutgroupsbeingthemostinterestedinthem. Itisno
accidentthatadetailedpaperwithananalysisoftheseproblems(Chitwood, 1958)was
theworkofaneminentspeciaUstonthesystematicsofnematodes.
ThecurrentlyvalidInternationalCodeofZoologicalNomenclaturedoesnotregulate
thenamesoftaxahigherthansuperfamily;itisoftensaidthat theydonotneed tobe
regulatedbecausetherearefewsuchnamesandtheyareallwidelyknown.Infact,this
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BulletinofZoologicalNomenclature48(1)March199 7
is absolutely not the case: they are not regulated only because, in so doing, it would
be very difficult not to produce a serious breakdown in existing customs concerning
theformationand utilizationofnamesofhighercategories. However, soonerorlater
we will be forced to do so, and it is better to discuss beforehand possible means of
regulatingthenomenclatureofhighercategoriesand possibleways tointroducesuch
regulation, in order that the transition be the least painful. In discussing the nomen-
clature ofhighercategories, I do not, however, believe that it is possible to take such
categories as kingdom or subkingdom into consideration, mostly because zoological
nomenclaturecan be applied only to one kingdom ofanimals and two subkingdoms
(unicellular and multicellular animals). For those who are interested, questions
concerning these categories are considered in the paper by Chitwood (1958) cited
above.
The names of higher categories are remarkably non-homogeneous in character.
Some ofthem are more orless tied to the name ofone ofthe genera included within
them, thatnametherebybeingthenomenclaturaltypeofthenameofthehigher-rank
taxon. Icallsuchnames'typified',followingStys&Kerzhner(1975).Othernamesare
basedonlyonthefeaturesofagiventaxon(albeitfarfromalwaysthemostcharacter-
istic ones) and are not at all connected with the names ofgenera included in these
taxa, and Icallsuchnames 'descriptive', afterthesameauthors. Examplesoftypified
names: Echinoidea, Sipunculida, Myzostomida, Blattoidea, Gadiformes; they are
clearlyconnectedwiththegeneraEchinus, Sipunculus, Myzostoma,BlattaandGadus.
Examplesofdescriptive names: Arthropoda, Crustacea, Insecta, Orthoptera. Itmust
be emphasized that the differences between these two types ofnames are most often
purelyformal.Forexample,thenameoftheorderActinodonta,proposedbyDouville
(1912),mayhavebeenbasedonthegenericnameActinodonta,butmorelikelyonone
oranotherpeculiarityofthehingeofthesebivalvemolluscs,eventhoughthisgeneric
namealreadyexistedin 1912andwithoutadoubtwasknowntoDouville.
Family-group names also once belonged to these two types, but the descriptive
namesamongthemwerealwaysconsiderablyfewer, andattheendofthelastcentury
thesedescriptivenameswerecompletelydisplacedbytypifiedones.Thismadeitposs-
ibletointroducerulesregulatingfamily-groupnamesinthe 1960's. Order-groupand
higher-rank names are a different matter. It is sufficient to glance through some old
nomenclators to understand that descriptive names given to higher-rank taxa are no
lessabundantthantypifiedones.Inthelastfewdecadesatendencyfortheintroduction
oftypified nameshasbeenclearlyevident. Theyaregenerallyacceptedinthesystem-
atics of birds, fish, polychaetes and nematodes, and are being introduced into the
systematicsofmolluscsandsomeotheranimalgroups.
The advantage of typified names is obvious: the usage of such names is easy to
regulate,onlyrequiringasmallamountofrephrasing(withoutchangingthebasicidea)
ofthoseArticlesoftheCodeconcernedwithnamesingeneralandwithfamily-group
names. In other words, the problems of the availabihty of names, authorship and
date of publication, priority and homonymy could be resolved in the spirit of the
established, customary regulations of the Code. In contrast, difficulties often arise
withdescriptivenames. Theaccumulation ofknowledgeabout any taxonomicgroup
usually leads to ademonstration that thespecial featuresexpressed in thedescriptive
name ofa group are not characteristic after all or are peculiar to only some ofits
representatives.Thiscausessomesystematiststowanttochangethenamesofgroups
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8 BulletinofZoologicalNomenclature48(1)March199
intooneswhichare,intheiropinion,moreappropriate,andwhich,incidentally,intime
also come to be shown not to be entirely suitable. The accumulation ofsystematic
knowledge inevitably also leads to the elevation in rank and subdivision ofgroups.
Whenthishappens,thedescriptivenamesgiventothesegroupsareeitherraisedinrank
(ashashappenedwithmostnames,forexampleGastropodaandProsobranchia)orthe
senseembodiedinthesenamesismaintainedatthesamerank,butnarrowedinscope.
ThusthecustomarynameInsectahadatthetimeofLinnaeusthemeaningthatisnow
embodiedinthenameArthropoda,anditwasnarroweddownlatertoitsusualsense;
furthermore,when theremoval ofasetofapterygotegroups from thisclassbecomes
generally accepted, this narrowing will become still greater. Similar transformations
first ofall refute usual notions about the tradition and convenience ofsuch names,
andsecondlycreatenomenclaturaldifficulties. Crustaceansarecurrentlydividedinto
several classes, for example into nine by Manton (1969). To which ofthese classes
shouldthenameCrustaceabelong? Sincetheseclassesarecontainedinasingletaxo-
nomicgroupingofhigherrank(superclassorsubphylum),thenitmaybebesttoretain
thisnameforthelattergrouping. Iftherewerenosuchhigher-rankgrouping,thenthe
nameCrustaceawouldprobablyhavesufferedthefateofthenameVermes.
Another inconvenience ofthe descriptive names is connected with a phenomenon
thatcanbecalledhemihomonymy.Sometimesthespellingofadescriptivenameiseasy
toconfusewiththatofatypifiedone,especiallyifithasasimilarstandardending.Yetit
turnsoutthatthegenuswhichwouldbethetypeofthatname,ifitwereatypifiedone,
doesnoteven belongto thattaxon. Forexample, amonggastropodmolluscsthereis
an order-group name Ditremata, but the genus Ditrema is not a mollusc at all, but a
fish. This circumstance already long ago compelled malacologists to avoid the name
Ditremata,replacingitwithanothernotsuff"eringfromsuchashortcoming.Thesame
is true for the widely known name ofone ofthe taxonomic groups ofcephalopod
molluscs,Teuthida,since Teuthisisthegenericnameofafish.
Alltheforegoingspeaksinfavoroftheintroductionoftypifiednamesfortaxaofall
ranks;however,carryingoutsuchareforminvolvesconsiderabledifficulties,themajor
onesofwhichwewilldiscussnow.
The first difficult problem is that ofstandard endings. In the literature there are a
great many systems ofstandard endings (Tables 1-3; see p. 17). More endings have
beenproposedforordinalgroupsthanforgroupsofhighertaxonomicrank.Eachsuch
systemhasbeenconstructedstartingfromtheprinciplesofeuphony,brevity,andease
ofdistinguishingrank. However, indoingthis, oneextremelyimportant requirement
oftheendingshasbeenforgotten,onewhichlimitsourchoicesverysubstantially.The
endings must be selected so that they completely, or in any case maximally, exclude
homonymic coincidences ofthe names ofhigher taxa with generic names. As we all
know, the Code considers homonyms only within groups (for example, within the
genus-groupandwithinthefamily-group),butnotbetweennamesbelongingtodiff'er-
entgroups.Thisisunderstandable,sincehomonymsbetweenagenus-groupnameand
anamebelongingtothefamily-groupalmostcannotarise; namesin thegenus-group
mustbeinthesingular(Article 1Ig)whilepluralendingsorendingsresemblingthem
are used forfamily-groupnames. Suchcasesareonly possibleinconnectionwith the
names ofsuperfamilies; for example, the genus Nuculoidea is included in the super-
familyNUCULOiDEA.Inthisconnection,itwouldbeworthwhiletodiscusschangingthe
ending recommended by the Code for superfamily names; in place of-oidea, -oideae
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BulletinofZoologicalNomenclature48(1)March 199 9
would be better. Therefore, in regulating names no higher than those ofthe family-
group, the Code justifiably ignores intergroup homonyms. But in proposing an
extensive system ofstandard endings for higher taxa, we must not forget about this
undesirable phenomenon. For example, let us look at the endings suggested by
Rohdendorf(1977).Themostdangerousonewithrespecttointergrouphomonymyis
theending-ina.Wecannamethousandsofgenericnamesendingwiththissequenceof
letters. Onlya numberofgenericnamesofbivalvemolluscsmay becited: Aphrodina,
Argina, Mytilina,Nuculina, Nayadinaandmanyothernames.Toavoidhomonymous
coincidenceswhenutilizingthisendingforthenamesofsuborders,wemustdistortthe
stem of the name of the genus utilized for the name of the suborder, for example
Mytileina in contrast to Mytilina(Scarlato& Starobogatov, 1979), and Helixina and
Limaxina incontrast to Helicinaand Limacina(Schileyko, 1979). Lessofadangerin
thisrespectare theendings-oda, -ona, -idea, -oida, -ida, and-omorpha. Forproofof
the possibility, in principle, ofcoincidence, here again are enumerated some generic
namesofbivalvemolluscs:Polymesoda,Phymesoda,Amesoda,Nuculoidea,Mytiloidea,
Axinopsida, Mytilomorpha, Modiomorpha, Sphenotomorpha. In view ofthe consider-
abledangerofintergrouphomonymy,itisobviousthatnotasingleendingterminating
in-aisatourdisposal.Thisdangerispracticallyeliminatedwithendingsterminatingin
-i,andisconsiderablyweakenedwithendingsterminatingin-esand-ae. Amongsuch
fortunate endings are those that are generally accepted for the names ofthe orders
ofbirds and fish and the suborders offish. Such endings are probably best reserved
for orders and suborders. The other endings proposed by me have been worked out
not only with regard to the usual requirements, but also primarily with the goal of
minimizing the danger of intergroup homonymy (Tables 1-3). The application of
standard endings to descriptive names is extremely undesirable. Firstly, this gives an
unaccustomed form to such names, which are preserved now only because they are
customary, and secondly this makes descriptive names similar to typified ones and
thereby increases the danger of confusion connected with the phenomenon of
hemihomonymydescribedabove.
The development ofstandard endings is one ofthe most difficult questions in the
nomenclature ofhigher taxa. In a number oftaxonomic groups ofanimals in which
typified names have long since been adopted, their own sets ofendings have become
customary, usually very limited sets (for orders and suborders). This adherance to
custom can have a negative impact during unification. To arrive at a unanimous
opinion will be very difficult and the pursuit oftradition, ofapparent stability, can
hopelesslywrecktheideaofthenomenclaturalstabilityofhighertaxa.
The second difficult problem is the coordination of categories. As we all know,
groups have been introduced into nomenclature in order to successfully apply the
PrincipleofCoordination. Itisimportanttonotethattheapplicationofthisprinciple
hasatwo-foldinfluenceonnomenclature.Firstly,thePrincipleofCoordinationletsus
reducethenumberofnamestoagreaterdegreeasmorerankedcategoriesarecoordi-
natedwithin agroup. Secondly, incombinationwith the PrincipleofPriorityitleads
to a breakdown in nomenclatural stability, again to a greaterdegree as more ranked
categoriesarejoinedwithinagroup,becausethereplacementorsuppressionofaname
basedonaparticulargenusleadsinevitablytothesuppressionorreplacementofallthe
namesinthatgroupthatarebasedonthesamegenus.ThefirstactionofthePrinciple
of Coordination must be considered positive, the second one obviously negative.
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Rohdendorf(1977)mentionsorder-,class-andphylum-groups onlyinhisdiscussion
ofasystemofstandardendingsandnevertalksaboutanapplicationofthePrincipleof
Coordination. However, from theexamples he presents, it isclear that hepersonally
does not recognize groups higher than the family-group and that he unites all the
supragenericcategoriesintoasinglefamily-to-phylumgroupinwhichallthecategories
arecoordinated.Suchtotalcoordinationeliminatesdisputesabouttheauthorshipand
dateofpublicationofs—omefamiliesofbirdsandinsects,sincetypifiednames(oratleast
onestypified/705/hoc seebelow)oftheordersofbirdswerepubUshedbyLinnaeus,
and typified names of the orders of insects by Laicharting (1781-1784), while the
familiesappearedmuchlater,inthe 19thcentury.Thusthequantityofnames,authors,
anddatesisreduced. Iteliminatesdifficultiesincaseswhen therank ofa taxonisnot
specifiedorisdenotedbyalittle-usedterm(forexample,stirps).However,totalcoordi-
nationhasaveryseriousdeficiencythatpreventsitswideintroduction.Arevisionofthe
systematicsofahigher-ranktaxoncaninvolvetwoprocesses:first,divisionorfusionof
families, orders, subclasses, etc., and second, transfer ofa family from one order to
another or from one subclass to another. If, as in the systematics ofinsects, the first
process predominates, then we get all advantages and see practically no deficiencies
withtotalcoordination.PossiblythisiswhyRohdendorf,asanentomologist,citedhis
own exampleswithcompletecoordination. However, ifthe second processpredomi-
nates, as in most groups ofinvertebrates, then the transfer ofa family must lead to
wholesalenamechangesforallthehighergroups.Thisdangerisalreadyexpressedtoa
high degree in those groups (forexample, hydroids) wheredifferent stages ofthe life
cycle have been described as diff'erent genera and as belonging to diff"erent families.
There is yet another source ofinstabihty with total coordination, taxonomic groups
knownbothinextantformandalso, toagreaterdegree,asfossilremains. Inthiscase
thefossilremains(which,ofcourse,cannotbestudiedwiththesamecompletenessas
extantorganisms)mayhavebeendividedintoindependentfamiliesbeforethemodern
ones, but further study can seriously change our views on their systematic position.
Thus,formanygroupsofanimalstheadoptionofaschemeoftotalcoordinationleads
to nomenclatural instability or requires special decisions about the conservation of
namescontrarytopriority. Makingspecialdecisionsineachindividualcasegenerally
floutstheveryideaofuniversalrules.
It is more rational to erect a small number ofgroups (most conveniently order-,
class-, and phylum-groups, based on the name ofthe basic category unique to each
group)and tocoordinatecategoriesonlywithinagroup. Indoingso, thequantity of
names,authorsanddatesdoesnotgrowverymuch,andthenomenclaturalstabiHtyof
higher-ranktaxaissecuredmoredependably,sinceaberrantandlittle-studiedfamilies
aretheonesmostexposedtothedangeroftransferfromonetaxontoanother,andthe
namesofhighertaxaarebasedprimarilyonthebestknownandcharacteristicgenera.
Inaddition, aswesawearlier, thepresenceofthreegroupsismoreconvenientforthe
gradualintroductionoftypifiednames,sinceitallowsustochangethenamesoflower
ranktaxafirstandthoseofthehighestranklater.Insodoing,thenameofataxonmay
beformedfromanyavailablegenericnameregardlessofwhichfamily-groupnamewas
publishedearliest. Thus, Laicharting(1781-1784) formed thenameofan orderfrom
the genus Cancer (incidentally, this name has priority over Decapoda), and a family
namebasedonthesamegenusfirstappearedin 1803,butin 1802Latreille(1802-1803)
published a family-group name (astacini) based on the genusAstacus. It is obvious
BulletinofZoologicalNomenclature48(1)March 1991 11
thatthisdoesnothavetoleadtothereplacementoftheordinalname.Therearerather
manysimilarcases.Theexamplewascitedaboveofanorder-grouptaxonwhosename
was typified by the generic name Actinodonta. The family name based on the same
genusistheyoungestinthewholetaxon.
With a three-group system ofcoordination, we can calmly consider names ofthe
order-groupand the family-group,even onesbased on thesamegenus, asoriginating
independently, and to ascribe to them different authors and dates ofpublication. In
connectionwiththenamesoftheordersofinsectspublished by Laichartingthatwere
discussed above, they remain with the same authorand date, yet 'Rasnitsyn, 1976' is
attached after the class, subclass and infraclass names based on the generic name
Scaraheus, since Laicharting did not propose such names for any unit ofthe class-
group.Asforlinkingthenamesofhighertaxawiththeoldestofthefamilynames,this
can be done as a supplementary means of stabilization by authors who are newly
publishingnamesoftaxa,iftheysodesire.
Thethirdproblem,perhapsthemostdifficultone,isthetransitionfromcontempor-
arynomenclaturewithdescriptiveandtypifiednamestoanomenclatureutilizingonly
typified names. Themostsimpleand radical solution is to rejectall descriptivenames
andchangethemtotypifiedones.Manyhaveproposedthis,amongthemRohdendorf.
Howeverthewholehistoryofbothzoologicalandbotanicalnomenclatureshowsthat
suchasuddenreformisabsolutelyimpossiblesinceitarousesaresoluteprotectiveness
in all zoologists who areaccustomed to certain names fororders, classes, and phyla.
The only way out is to introduce typified names gradually in the course of large
systematic revisions or as alternatives to descriptive names. It must be remembered
herethatthenomenclaturalinconvenienceofdescriptivenames(thatareuncoveredin
the course ofrevisions) will itselfbe the most powerful factor in the introduction of
typifiedones. Iamcategoricallyagains—timmediatechangesinsuchcustomarynames
as Insecta, MolluscaandGastropoda time itselfwill takecare ofthese namesasit
hasclearedawaythenolesscustomaryandunderstandablenamesZoophyta.Vermes,
Gephyrea, Myriapoda and Pseudoneuroptera, and as it is preparing to do with the
namesReptiliaandCrustacea. Inthecourseofthisprocess,thethree-groupsystemof
coordination isgood insurance ofthegradualness ofthetransition, since thesystem-
aticsofordersissubjecttorevisionmoreoftenthanthesystematicsofclassesandeven
moreoftenthanthesystematicsofphyla. Itmustberecommendedattheverystartnot
tointroducenewdescriptivenamesandnottoresurrectforgottenones(eventhoughso
instructedbytheadoptionintheCodeofcriteriadistinguishingforgottennamesfrom
utilized ones). One such recommendation is already strongly reducing the numberof
descriptivenames inuseasa regularresult. Anotherbasisforsuppressingdescriptive
names is discussed above as hemihomonymy. Names giving rise to nomenclatural
confusionshouldbethefirsttobesuppressed.Onthecontrary,ifhemihomonymydoes
notarise,thensuchnamesmaybestabilizedbychangingthemintotypifiedones.The
nameofaclassofpseudocoelomateworms, Kinorhyncha,isdescriptive, andupuntil
recentlyithasnotbeenconnectedwithanyavailablegenericname.Ithasbeenpointed
out that the name ofone ofthe genera ofthis class, Trachydemus (incidentally, this
includes the biggest representatives of the class), is a junior homonym, and in this
connection it was changed by Sheremetevskii (1974) to Kinorhynchus. which also
changed the name ofthe class into a typified one. The question may arise, at what
time is the name considered to be introduced into nomenclature, with the date ofits
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publicationwithinaparticularcoordinationgrouporwiththedateoftypification?Itis
apparentthattheobjectiveofthestabilizationofnomenclaturerequiresthatpriorityin
agivencasebereckonedfromthedateofpublication.Thisistosomedegreeanalogous
withcaseswheretheCodepermitstheavailabilityofagenericnamepublished(uptoa
certain date [1930]) without including any nominal species in it. What we have been
talking about opens one more route, albeit not a very effective one, to reduce the
numberofdescriptivenamesandyetretaincustomarynames.
The difficulties discussed above are, in my view, the most substantial ones on the
pathwaytowardstheregulationofthenamesoftaxaofhigherrank. Manyotherswill
probablyarise,hopefullyonesthatarelessseriousandeasiertoovercome.Itseemsthat
theprocessofregulationofthenomenclatureofhigherranktaxaneedstobeginwitha
systemofrecommendationsonthistheme,andactionsconducivetoareductioninthe
numberofdescriptivenamesin useand theretention ofcustomarynames, aslongas
theydonotcauseconfusion. Then, in thecourseofsystematicrevisions, newtypified
nameswill emerge and the numberofdescriptive ones will become still fewer; in this
waytypifiednameswillemergeasequivalentalternativestodescriptiveones.Onlyafter
this (and the process will probably take several decades) will it bejustifiable to raise
thequestion about a more strict regulation ofthe nomenclature ofhighertaxa and a
supplementoftheCodewithcorrespondingArticles.
Therefore,intheconclusionofthispaperIwouldhketosetforthadraftofasystem
ofsuch recommendations in order that all who are interested in the improvement of
zoologicalnomenclaturecan familiarizethemselveswithit,andtoprepareabasisfor
furtherdiscussionconcerningthesequestions.
Adraftofrecommendationsfortheregulationofthenomenclatureoftaxaofrank
higherthansuperfamily
Generalfeaturesofthenamesofhighertaxa
1 Theproposalsheredonothavetheforceoftheobligatoryruleslaidoutinthe
Articles ofthe International Code ofZoologicalNomenclature but have the force of
recommendations.
2. Thenamesofhighertaxonomiccategoriesaredividedintotypifiedanddescrip-
tiveones.Atypifiednameisonethatisformedfromthestemofanavailablenameofa
nominal genusincluded in the taxon concerned, that generic name thereby beingthe
nomenclaturaltypeofthenameofthehighercategorytaxon.Adescriptivenameisone
thatisnotconnectedwithanyavailablenameofanominalgenusincludedinthegiven
taxon.Thecoincidenceofthestemofthenameofahighercategorytaxonwiththestem
ofthe name ofa nominal genus not included in that taxon does not make the name
typified.
3. In taxonomic groups in which a standard compound ending is employed, for
example -optera in insect systematics, -osauria in reptile systematics, -omonadida in
flagellate systematics, etc., a name is considered typified if: (a) after removal ofan
ending, its stem coincideswith the stem ofthe name ofa genus included in the given
taxon, (b) it itself, in its entirety, coincides with the stem of the name of a genus
includedinthegiventaxon.Thegenericnamewithwhichsuchacoincidenceoccursis
consideredthenomenclaturaltypeofthattypifiedname.
BulletinofZoologicalNomenclature48(1)March 1991 13
Example. ThenameCoelurosauriacomesfromthegenericname Coelurus,and the
name Segnosauria from the generic name Segnosaurus: both names are considered
typifiedandtherespectivegenericnamesareconsideredthenomenclaturaltypesofthe
names of the corresponding higher taxa (only in the first case the ending must be
considered tobe-osauriaandinthesecondtobe-ia).
Ifboth coincidences listed above occur, and the author did not clearly designate
the nomenclatural type (or it is not evident from the author's original text), then the
nomenclatural type is established upon the first subsequent designation or upon the
firstchangeofendingthatunambiguouslyidentifiesthenomenclaturaltype.
4. Within a taxon havinga descriptive name, the proposal ofa new genuswith a
namewhosestemcoincideswiththatofthenameofthegiventaxonchangesthetaxon's
nameintoa typified one, provided thatthenewgenericnameisavailableand isnota
juniorhomonym.
Descriptivenames
5. Theapplicationofadescriptivenameisdeterminedeitheronlybythemeaning
(content)embodied in it, independent ofthe rank accorded to it, oronly by the rank
customarily accorded to it, independent ofthe meaning (content) embodied in it. In
eithercasetheauthoranddateareretainedthroughanychangesinrankorcontent.
Example: In thetimeofLinnaeus, Insectawasconsideredaclass, althoughlaterits
contentchangedsubstantiallyincomparisonwiththeoriginal;incontrast,themeaning
inherentinthenameBivalviahaschangedverylittleoverthesametimespan,whilethis
taxon'srankhasbeenraisedsubstantially.Inbothcaseswemustplace'Linnaeus, 1758'
afterthename.
6. Descriptivenamesareavailableifthey:(a)areexpresslyproposedforataxonof
specified rankand(b)arecharacterizedastocontent,aswithalistofthesubordinate
taxa included in the named taxon, or are provided with a diagnosis allowingcertain
taxaoflowerranktobeassignedtoit,orarespecificallyproposedinplaceofanother
descriptivename.
7. Descriptive names are not available if they: (a) are first proposed in the
synonymy ofanother available name (descriptive or typified), (b) are proposed con-
ditionally orforahypotheticalgroup, (c)areproposedexpresslyin placeofan avail-
able typified name, (d) are not either characterized as to content or provided with a
diagnosis,or(e)aregivenwithoutspecifyingtherankofthetaxonforwhichthenameis
proposed.
8. It is categorically not recommended: (a) to introduce new descriptive names,
(b)toutilizedescriptivenamesemployedbyfiveorfewerauthorsintenorfewerworks
duringthelast 50years, and (c) to replace typified namesbydescriptiveonesthatare
notgenerallyaccepted.
9. Ifadescriptivenamehasachievedwideusage,thenthequestionofitsretention
mayonlybediscussedinthosecaseswhereithaspriorityovera typifiednameforthe
sametaxon.
10. Confusing typifiednames. Ifthe stem ofadescriptivenamecoincideswith the
stemofanameofanominalgenusnotincludedinthegiventaxon,thentheuseofthat
nameisundesirable.
11. In dividing a taxon that has a descriptive name into unequal parts of the
same rank, it is recommended to give the newlycreated taxa typified names; the old
14 BulletinofZoologicalNomenclature48(1)March1991
descriptivename,incaseofitsgeneralacceptance,mayberetainedonlyforthelarger
ofthecreatedtaxaorforataxonofhigherrankunitingthenewlycreatedones.
12. Individingataxonthathasadescriptivenameintoseveralequally-sizedones,or
inanyothercasewhenitisdifficulttodeterminehowtoapplytheoriginalname,itis
recommendedtogivetypifiednamestothenewlycreatedtaxa.Theoriginalnamemay
thenberetainedforataxonofhigherrankunitingthenewlycreatedones.
13. Inunitingtwoormoretaxathathavedescriptivenamesintoataxonofthesame
rank, the name ofthe united taxon is chosen according to the Principle ofPriority,
providedthattheauthordoesnotwishtogivetheunitedtaxonatypifiedname.
14. In uniting two ormore taxa, one ormore ofwhich has atypified name, into a
taxonofthesamerank,itisrecommendedthattheunifiedtaxonhavethetypifiedname
(or the oldest ofthe typified names ifthere are several), provided that this does not
requireachangeinawidelyusedandgenerallyaccepteddescriptivename.Inthelatter
case,atypifiednameisintroducedasanalternativetothedescriptiveone.
15. Homonyms of descriptive names. Of two or more homonymous names (i.e.
identical in their stems, but based on different taxa), the one which was introduced
earliestisretained,providedthatitisnotforgotten(point8(b))orthatoneofthemore
juniornamesisnotwidelyused. Itisrecommended tochangetherejecteddescriptive
namestotypifiedones.Ifhomonymyarisesbetweenadescriptiveandatypifiedname,
thedescriptiveoneissubjecttoreplacementregardlessofpriority.
16. Synonymsofdescriptivenames. Ofsynonymousdescriptivenames(i.e. apply-
ingtothesametaxon),theoldestissubjecttoretention,providedthatitisnotforgotten
(point8(b))orthatthisdoesnotcontradictthebroaduseofoneofthemorejuniornames.
Ifadescriptiveandatypifiednamearesynonyms,thenthedescriptiveoneisretainedif
thefollowingtwoconditionssimultaneouslyapply: (1)ithaspriorityoverthetypified
one,(2)itiswidelyusedfordenotingthegiventaxon.Theconservationofadescriptive
nameisnotobligatoryifauthorsprefertomakeuseofatypifiednameintheirworks.
TypifiedNames
17. Theapplicationofatypifiednameisdeterminedonlybyitsnomenclaturaltype,
i.e.thetypegenus,thestemofwhosenameisthebasisfortheformationofthenameof
thehighertaxon.
18. A typified name is considered available ifit is: (a) expressly proposed for a
definitetaxon havinga specified rank, (b) based on a genericnamethat isconsidered
validatthetimeofproposalofthenamedtaxonorthatfulfilspoint4,(c)accompanied
byadiagnosisorindication(points20,21).Anameisalsoavailableifitisproposedfor
ataxonconsideredatthetimeofitsproposalasbelongingto theplantkingdom, and
in that context meeting the conditions ofa validly published name according to the
InternationalCodeofBotanicalNomenclature.
19. A typified name of a higher category taxon published before 1900 in not
completely Latinized form is available with its original author and date, but in the
appropriateLatinizedform,ifitmeetsthecriteriaofpoint 18.
20. Indicationsapplicable to typified names ofhigher taxaare: (1)a bibUographic
reference to an earlier published diagnosis irrespective ofthe rank ofthe taxon for
which thecited diagnosiswas published, (2) a characterization ofthecontents ofthe
named taxon, i.e. an enumeration of the subordinate taxa that go into the newly
proposedone,(3)aproposalofanewnameexpresslyasareplacementforanavailable
..
BulletinofZoologicalNomenclature48(1)March 1991 15
name(typifiedordescriptive)alreadyinexistance,(4)publicationofatypifiednamein
thesynonymyofadescriptiveone(butnotofatypifiedone).
21 Upuntiladateexpresslyestablished upontheadoptionofthisdraft,theforma-
tionofanewtypifiednameofahighertaxononthebasisofthename,validatthattime,
ofanominalgenusisconsideredanindication.
22. Upontheintroductionofanewtypifiednameasareplacementforapreviously
existing descriptive one, and also upon the publication ofa new typified name in the
synonymyofadescriptiveone,aprecisedesignationofrankofthetaxonismandatory.
23. A typified name is notconsidered available ifit: (a) is based on an unavailable
generic name, (b) is proposed conditionally or for a hypothetical group, (c) is pre-
sented without an indication ofthe rank ofthe taxon forwhich it is proposed, (d) is
published in the synonymy ofa typified name, (e) after a date to be established is
unaccompaniedbyadiagnosisoranindication.
24. The cat—egories to which typified names ofhigher taxa belong are divided into
three groups the phylum-group, the class-group and the order-group. For names
belongingtoaparticularcategory,fixedstandardendingsarerecommended.
25. The phylum-group includes the following categories (recommended standard
endings given in parentheses): superdivision (-ozoi), division (-ozoides), subdiv-
ision (-ozoidi), superphylum (-ozoacei), phylum (-ozoes), subphylum (-ozoines),
infraphylum(-ozoae).
26. The class-group includes the following categories (recommended standard
endings given in parentheses): superclass (-idees), class (-iodes), subclass (-iones),
infraclass(-ioni).
27. Theorder-groupincludesthefollowingcategories(recommendedendingsgiven
in parentheses): cohort (-omorphi), superorder (-iformii), order (-iformes), suborder
(-oidei),infraorder(-oinei).
28. Categoriesarecoordinatedwithinagroup;i.e. allthecategorieswithinagroup
have equal status in nomenclature and are subject to the same recommendations. A
namepublishedforataxoninanycategorywithinagroupandbasedonagivengenus
istherebyavailablewithitsoriginalauthoranddateforalltaxawithinthatgroupthat
arebasedonthesametypegenus,withcorrespondingchangesintheending.
29. Raisingorloweringtherankofataxonbeyondthelimitsofthegroupinwhich
its name was proposed amounts to the proposal ofa new taxon based on the same
genericnameinanothergroup.
30. The name of a higher rank taxon with an ending not corresponding to the
recommended one for taxa ofthe given category is available with its original author
anddate, butwiththecorrespondingcorrectedending.
31 Untiladateexpresslyestablishedupontheadoptionofthisdraft,theutilization
ofdifferent standardendingsincommon usein systematicgroupsisallowed, butitis
moredesirabletousetherecommendedones(points25,26,27).
32. The appraisal ofthegroupmembership ofa rarelyused orundefinedcategory
(e.g. stirps,series,etc.)andalsoofcategoriesusedinclearlyunusualsensesisresolved
bythefirstsubsequentdeterminationoftheirusage.
(1) All categories higher than superfamily and lower than order belong to the
order-group.
(2) All categories higher than phylum and lower than subkingdom belong to the
phylum-group.