MALACOLOGIA, 2005, 47(1-2): 1-397 CLASSIFICATION AND NOMENCLÁTOR OF GASTROPOD FAMILIES Researchedand edited by Philippe Bouchet&Jean-Pierre Rocroi MuséumNationald'HistoireNaturelle 55rueBuffon, 75005Paris, France:[email protected] Withclassification by JiriFryda Czech GeologicalSurvey Praha, CzechRepublic Bernhard Hausdorf ZoologischesInstitut UniversitätHamburg, Germany Winston Ponder TheAustralianMuseum Sydney, NewSouth Wales,Australia ÁngelValdés NaturalHistoryMuseum ofLosAngeles County LosAngeles, California, USA AndersWaren NaturhistoriskaRiksmuseet Stockholm, Sweden BOUCHET&ROCROI 2 CONTENTS Abstract 4 Introduction 4 Part 1. NomenclátorofGastropod Family-Group Names [Bouchet & Rocroi] 5 ASummary ofthe Rules ofNomenclatureApplying to Family-Group Names 5 Availability of Names 5 Formation of Names 8 Validity 10 Principle ofCoordination 11 Status ofNames in the Official Listof Family-Group Names in Zoology 12 Cases to be Submitted to the Commission 12 Nomenclátor 12 Epidemiology ofGastropod Family-Group Names 12 Format ofthe List 16 NomenclátorofGastropod Family-Group Names 17 List ofGastropod NamesAbove the Family Group 187 Part2. Working Classification ofthe Gastropoda [Bouchet, Fiyda, Hausdorf, Ponder, Valdés & Waren] 239 Paleozoic molluscs ofuncertain systematic position, Neritimorpha, fossil "archaeogastropods"', fossil lowercaenogastropods and fossil lower Heterobranchia [Fryda &Bouchef] Modern "archaeogastropods" [Waren & Bouchef] Modern Caenogastropoda, modern lower Heterobranchia [Ponder& Bouchef] Cephalaspidea, Thecosomata, Gymnosomata,Aplysiomorpha, Umbraculida, Acochlidiacea, Sacoglossa, Cylindobullida, Nudipleura [Valdés & Bouchef] Pulmonata [Hausdorf& Bouchef] Paleozoic molluscs ofuncertain systematic position 241 Basal taxa that are certainly Gastropoda 242 Clade Patellogastropoda 242 Clade Vetigastropoda 243 Clade Cocculiniformia 245 Clade Neritimorpha 245 Paleozoic Neritimorpha ofuncertain position 245 Clade Cyrtoneritimorpha 246 Clade Cycloneritimorpha 246 TABLEOFCONTENTS Clade Caenogastropoda 247 Caenogastropoda of uncertain systematic position 247 Informal GroupArchitaenioglossa 247 Clade Sorbeoconcha 248 Clade Hypsogastropoda 249 Clade Littohnimorpha 250 Informai Group Ptenoglossa 254 Clade Neogastropoda 254 Clade Heterobranchia 257 Informai Group Lower Heterobranchia 257 Informai Group Opisthobranchia 258 Clade Cephalaspidea 258 Clade Thecosomata 259 Clade Gymnosomata 259 CladeAplysiomorpha 260 "Group"Acochlidiacea 260 Clade Sacoglossa 260 "Group" Cylindrobullida 261 Clade Umbraculida 261 Clade Nudipleura 261 Clade Pleurobranchomorpha 261 Clade Nudibranchia 261 Clade Euctenidiacea 261 Clade Dexiarchia 262 Clade Pseudoeuctenidiacea 262 Clade Cladobranchia 262 Clade Euarminida 262 Clade Dendronotida 262 CladeAeolidida 263 Informai Group Pulmonata 263 Informai Group Basommatophora 263 Clade Eupulmonata 264 Clade Systellommatophora 264 Clade Stylommatophora 264 Clade Elasmognatha 264 Clade Orthurethra 265 Informai Group Sigmurethra 266 Acknowledgements 284 References [Bouchet & Rocroi] 284 Index 369 BOUCHET&ROCROI ABSTRACT About2,400 namesatthe rankofsubtribe, tribe, subfamily, familyand superfamilyhave been proposed for Recent and fossil gastropods. All names are listed in a nomenclátor giving full bibliographical reference, date of publication, type genus, and their nomencla- tura! availability and validity under the International Code of Zoological Nomenclature. Another730 names, established forcategoriesabovethefamily-group, and not regulated by the Code, are listed separately. A working classification attempts to reconcile recent advances in the phylogeny of the Gastropoda, using unranked clades above superfami- lies, andthemoretraditional approach, using hierarchical ranking belowsuperfamily.Alto- gether,theclassification recognizesasvalid atotalof611 families, ofwhich202areknown exclusively as fossils and 409 occur in the Recent with or without a fossil record. The nomenclátor and classification will be updated in forthcoming editions to be published electronically. INTRODUCTION not to address the debate on classification methodologies or hierarchical vs non-hierar- Molluscan taxonomists routinelyusea num- chicalclassifications. Conversely,wehopethat berofspecies-andgenus-level nomenclators the nomenclatural part has the potential to thateitherareshared with the restofzoology remain a reference source for a longer time, (Sherborn 1902, 1922-1932; Neave 1939- as it will become outdated mainly by newly 1950, continued byEdwardsatal. 1966-1996) established names. orare specifictothe Mollusca (Ruhoff 1980). The present publication is the result of bib- Regrettably, however, there is no universal liographical workstarted in 1987to compilea nomenclátor of molluscan family-group nomenclátorofsupraspecific namescovering names, and asaconsequenceofthedifficulty all molluscan taxa. Recent and fossil, other in establishing their authors and dates, tax- than Cephalopoda. All primary literature has onomists do not always cite them in classifi- been checked and copied from the original cations. Even when these are cited, a proper sources (Bouchet & Rocroi 1992). A total of bibliographical referenceisoften lacking.This, 25,000genus-group(believedtobe97%com- in addition toan incomplete understanding or plete), 3,700 family-group names, and 1,150 applicationoftherulesofnomenclatureabove namesabovethefamily-group (both believed genus level, contributes to nomenclatural to be more than 99% complete) have been unstability. The purpose ofthe present paper captured. The result is a loose-leafpaperver- is to provide accurate bibliographical and no- sion and an electronicdatabase. The present menclatural data for gastropod family-group paper reports on our results on the names. The paper is organized in two parts: supraspecificnamesthathavebeen proposed Part 1 is a nomenclátor of 2,400 names that for the Gastropoda, which alone account for have been proposed for Recent and fossil 70% ofthe names in our nomenclátor. gastropods atthe rank ofsubtribe, tribe, sub- The International Code on Zoological No- family, family and superfamily; Part 2 places menclature(4"'edition) hassettheconditions thesenamesinaclassification. Inthecurrently fortheapproval ofa "ListofAvailable Names" very active phase of réévaluation of the phy- (Art. 79). Names entered in the List are logenyofthegastropods, the classification is deemed to have the date, availability, and bound to become outdated. It will also elicit othernomenclaturalattributesgiven intheList. controversy, asdifferenttaxonomists havedif- In addition, the List would be closed, that is ferentapproachestoclassification. However, names not entered in the List would be un- a mere alphabetical listing of gastropod fam- available under the Code. The List would be ily-group nameswould be insufficientto bring approved in parts, andgastropodfamily-group totheattentionofsystematiststhenamesthey names could constitute one such "Partofthe need to considerwhen they are reassessing List". Weencourage usersofthe presentpub- the classification ofselected parts ofthe Gas- lication to notify us with any omission and er- tropoda. Although Part 2 attempts to reflect ror they would notice, so that the present the current state-of-the-art ofgastropod clas- nomenclátor, after amendments and correc- sification, it should therefore essentially be tions, could be submitted to ICZN to become viewed as a guide to nomenclaturally avail- an official Partofthe List ofAvailable Names able names, as the purpose of this paper is inZoology. NOMENCLÁTOROF GASTROPOD FAMILIES Part 1. NOMENCLÁTOR OF GASTROPOD FAMILY-GROUP NAMES ASummaryofthe RulesofNomenclature (2)"Afamily-group namewhenfirstpublished Applying to Family-Group Names must[...] beclearlyusedasascientificname to denote a suprageneric taxon and not The InternationalCodeofZoological Nomen- merely as a plural noun or adjective refer- clature (ICZN) defines the family group as in- ring to the members of a genus" [Art. cluding the taxa "at the ranks ofsuperfamily, 11.7.1.2]. family, subfamily,tribe, subthbe, andanyother Two cases need to be discussed here: da rankbelowsuperfamilyand abovegenusthat Costa'sfamilynamesandTroschel's names may be desired" (Art. 35.1). The Code does established as plurals. notregulatethe namesoftaxaabovethefam- Da Costa (1776) appears to have been the ilygroup(sometimestermedtheclassgroup), first authorwho used the word "family" in a butfamily-groupnamesarefullysubjecttothe classification of the molluscs, and these provisions of the Code, which determine namesrequirespecificdiscussion. DaCosta amongothershowthenamesshall beformed, subdivided the shelled molluscs into three their availability, and nomenclatural validity. divisions: Univalves, Bivalves and Multi- Whereassome rulesapplytoall names inthe valves. Eachdivisionwasfurthersubdivided species, genusandfamilygroups, otherrules intoorders, sections(inoneorderofbivalves apply specifically to family-group names. As only), andfamilies. Shelled molluscs{sensu these rulesaresometimes little knownormis- da Costa)consisted of32families, ofwhich understood, it may be appropriate to summa- 16familiesare"Univalves"(i.e., gastropods, rize howtheyaffectfamily-group names. scaphopodsandcephalopods). Someofthe family names (Patella, Haliotis, Cylindri, AvailabilityofNames Voluta, Cassides, Trochi, Buccina and Murex)are Latin names, apparentlyformed Articles 10-20 determine the conditions of on a stem-genus, and it is necessaryto dis- availabilityofscientific names. Ofspecific rel- cusstheiravailabilityundertheCode. First, evance to this nomenclátor of family-group it should be noted that da Costa uses cer- names are Arts. 11.7 and 13.2, which state tain genericnameswith a meaning radically that: differentfromthatofhiscontemporaries. For instance, da Costa uses "Voluta or Volute" (1)"Afamily-group namewhenfirstpublished for species of Conus, but the only species [...] must be a noun in the nominative plural of Volutidae illustrated by him is identified formedfromthestemofanavailablegeneric as the "Melon Tun" of the family Globosa. name[...];thegenericnamemustbea name Da Costa's Strombus is a fasciolariid, then used as valid in the new family-group whereasheillustratesaspeciesofStrombus taxon"[Art. 11.7.1.1]. as"AMurexoftheAlatagenus". Second, da Examples: Costa's family names are most frequently Because Phobalea is not an available ge- formed by the first word of polynominal ge- neric name, the name Priobaleinae A. J. nericnames. Forinstance,thefamilyCylindri Wagner, 1922, is notan available name. containstwogenera, Cylindriemarginatiand The name Gymnosomata Blainville, 1824, Cylindri marginati. The family Buccina con- established asafamily, is notavailableas a tains six genera: Buccina Canaliculata, family-group name because itis notformed Buccina Recurvirostra, Buccina Rostrata, from agenus name. (Thisdoes notaffectits Buccina Umbilicata, Buccina Columella availabilitybythosewhowanttouseitabove dentata vel plicata, and Strombus [a superfamily, as such names are not regu- fasciolariid, seeabove]. Othernames, such lated bythe Code). as Turbinata involuta, Auris Cochlea, Da Motta (1995) established the name Globosa, Cochleae, and even Voluta, are Textiliinae, based on "Cylindrus [sic! = Cyl- plurals notbasedon agenus. In conclusion, inder] Montfort, 1810asthetypegenus"and even in the context of his time, da Costa's treated Textilia Swainson, 1840, as a syn- usage offamily and genus names is incon- onym and thus not as a valid name. Under sistentwiththe principlesofArticles4.1 and Art. 11.7.1.1 of the Code, Textiliinae is not 11.7.1.2 ofthe Code. It seems best to inter- anavailablename. pret Da Costa's family names as plural BOUCHET&ROCRO! nounsthatdo notqualifyunderArt. 11.7.1.2. of families" [translated from German by Troschel (1857 [in 1856-1891]) used the D. Kadolsky]. names Bithyniae, Lithoglyphi, Hydrobiae, Such names could perhaps be considered Ancyloti,Thiaraeand Pachychili in headings tobe"meansoftemporaryreference" inthe thathaveusuallybeenconsideredtodenote senseofArt. 1.3.5 (Kadolsky, pers. comm.), family-group rank. However, Troschel's which would exclude them from the provi- (1857: 95-129) treatment of these names sions of the Code. However, the names contrastswiththe restofhiswork (Troschel Bithyniidae (Opinions 475 and 1664) and 1856-1863 [in 1856-1891]), in which he Hydrobiidae (Opinion 2034) have been stated the ranks ofthe categories he used placedontheOfficial ListwithTroschel, 1857 and formed the names with the endings as author. We see two alternatives on how -idea, -ina, or -acea. Troschel's intentions to treatTroschel's (1857) names: (a) either with regard to the names formed as plurals be inconsistent and treat Bithyniae and areexplained on pp. 94-95: Hydrobiae as available and Lithoglyphi, "J. E. Gray, inthesystemsummarizedabove Ancyloti, Thiarae and Pachychili as unavail- [Gray, 1853], characterizedeachfamily, and able; (b) orbe consistent and treatthem all grouped them according to the constitution as available (contrary to Art. 11.7.1.2) or ofthe operculum. would have liked to fol- unavailable (contraryto Opinions 1664 and I low his subdivision in ourdescription ofthe 2034). Because there are no negative no- dentition, if the resulting differentiations menclaturalconsequences(nodisplacement would have agreed with Gray's families. In ofaccepted valid names), and because no- the Cyclostomacea in the older sense the menclature becomes impenetrablewhen its constitution of the operculum provided an application requires reference to too many excellentguidetothedifferentiation offami- specific decisions, we have decided to be lies, and the dentition confirmed this. Here consistent and treat all of Troschel's 1857 clarification is noteasy. I studied and drewa as unavailable. This has also the positive large numberofopercula, usuallyofjustthe consequence ofeliminatingAncyloti which, same species of which I studied the denti- ifconsideredanavailablename,would have tion. I did not gain a clear-cut correspon- to be treated as an incorrect original spell- dence from this, and therefore cannot ingof"Anculosinae", basedonAnculosaSay, I decide to assume families on the basis of 1821; "Anculosinae Troschel, 1857" would operculardifferences. Likewise would not then be a seniorsynonym ofPleuroceridae I liketo basefamilies based on certain pecu- P. Fischer, 1865(1863). liarities of the dentition, because cannot I foreseetheconsequencesdespitemyrather (3)"Afamily-groupnamewhenfirstpublished rich material, and because genera which must [...] not be based on certain names hitherto were [considered to be] distant, applied onlytofossilsand ending in the suf- would become closely related, and vice fix -ites, -ytes, or -ithes [Art. 20]" [Art. versa.Therefore, nootherwayis leftforme 11.7.1.4]. but to discuss the genera in small groups, Example: withoutwishing toassign tothem thevalue CypraeacitinaeSchilder, 1930, isnotanavail- able name because its type genus Cypraeac//esSchlotheim, 1820, is notavail- TABLE 1. Authorship of family-group names ableunderArt. 20. when Troschers 1857 plurals are treated as unavailable. (4) "Ifa family-group namewas published be- fore 1900, [...] but not in latinized form, it is availablewith itsoriginalauthoranddateonly Spelling inTroschel, Firstavailabilityafter if it has been latinized by later authors and 1857 Troschel has been generally accepted as valid by Ancyloti not used afterTroschel authors interested in the group concerned Bithyniae Gray, 1857 and as dating from that first publication in Hydrobiae Stimpson, 1865 vernacularform"[Art. 11.7.2]. Examples. Lithoglyphi Tryon, 1866 Pachychili P. Fischer&Crosse, 1892 "Styliolacées" (French vernacular) of Fol, Thiarae Gill, 1871 1875 [published before 1900 but never latinized], is notan available name. . , NOMENCLÁTOROFGASTROPOD FAMILIES TheauthorofScurriini isLindberg, 1988,and 2000, and also was not rejected by an au- notThiem, 1917,whoestablished"Scurrilden" thor who, after 1960 and before 2000, ex- a German vernacular name published after pressly applied Article 13 of the current 1900, and thus notan available name. editionsofthe Code" [Art. 13.2.1]. The author of the name Facelininae is not Tosummarize: Vayssière, 1888, because when Bergh es- - before 1931: description or definition not tablished itinthe Latinform, hedid notrefer necessary; to the French vernacular "Facelinidés" of -after 1930and before 1961: description or Vayssière, and the name is now universally definition necessary,withexceptionsruled attributedto Bergh, 1889. byArt. 13.2.1; The name Titiscaniidae is universally attrib- - after 1960: description ordefinition neces- uted to Bergh, 1890, who established it as sary,withoutexception. theGermanvernacular"DieTitiscanien, eine Examples: Familie der rhipidoglossen Gasteropoden", Knight (1956) introduced numerous family although itwasfirstlatinized byThiele, 1891 group names without a description andjus- The majordifficulty in theapplication ofthis tified his action by the following sentence: paragraph concerns names introduced "Sincethefull systematictreatmentandfull mostlybyFrenchauthorsbetween 1800and diagnoses of these taxa will appear within 1830. Forexample, Lamarck, Férussac, and the yearand since diagnoses are not requi- Latreille, created numerous names in ver- siteforvalidityoffamilial names,though rec- nacularformthatwereoften latinizedbytheir ommended, theyareomitted here". Thus, it translatorsand/orfollowers, notablyMenke, wasnotbyoversightordeliberateignorance Children, and Bowdich. Although many of ofthe rules of nomenclature that Knight de- these names are now accepted as valid in cided nottogiveanydescription. The name currentclassifications, there is no"generally Euphemitinae Knight, 1956, establishedwith- accepted"usage regardingtheirauthorship. out a description ordefinition, is now in cur- One ofthe reasons contributing to this lack rentuseand aftributed to Knight, 1956, and ofestablished consensus is that manytrea- nottoKnight, Batten&Yochelson, 1960,who tises and textbooks of malacology deliber- ftrst gave a diagnosis. Euphemitinae Knight, atelyomitauthorshipforfamily-groupnames. 1956, is available underArt. 13.2.1. For that reason, different authors have in- Becausethename Bertheliniinaewasestab- terpreted Article 11.7.2 of the Code differ- lished by Beets, 1949,withoutadescription ently, a situation that perpetuated the lack ordefinition, itwas regarded as unavailable ofconsensus. from this original publication by Le Renard étal. (1996)underArt. 13aofthe3rdedition (5)Description/Diagnosis. of the Code then in force. Bertheliniinae Sincethe 1960editionoftheCode,Art. 13.1 Beets, 1949, is not an available name, but requiresthat: Bertheliniinae Keen & Smith, 1961, is avail- "Tobeavailable, everynewname published able because these authors provided a di- after 1930 [...] must agnosis. 13.1.1. beaccompanied bya description or The name Microdisculidaewas established definitionthatstatesinwordscharactersthat by Iredale & McMichael, 1962, without a are purported to differentiate the taxon, or description or definition, and a description 13.1.2. be accompanied by a bibliographic ordefinition has not been published subse- referencetosuchapublishedstatement[...]". quentlybyanyauthor. Microdisculidaeisnot Applicability of this rule to family-group anavailable name. names established after 1960 is unambigu- Because the name Distorsioninae was es- ous. Conversely, its application to names tablished byKuroda, Habe&Oyama, 1971 published after 1930 and before 1961 was, without a description or definition, it is un- underthe 1''',2"'^and 3'^*editionsoftheCode, available from that publication. Distorsi- controversial (Bock, 1994). To leave some oninae is available from Beu, 1981, who flexibilityon this issue, the4th edition ofthe published adiagnosis. Codenowallowsthat: "Afamily-groupname first published after 1930 and before 1961 (6)Conditional proposal. which does not satisfy the provisions ofAr- "Anewnameornomenclaturalactproposed ticle 13.1 is available from its original publi- conditionallyand publishedafter 1960 isnot cation only if it was used as valid before thereby madeavailable" [Art. 15.1]. BOUCHET&ROCROI 8 Example: LaiocochliinaeGolikov&Starobogatov, 1987, Whenestablishingthe newgenusLapinura, is formed from Laiocochlis Dunker & Er.&Ev. Marcus(1970)wrote: "[Metaruncina Metzger, 1874, oneofseveral original spell- setoensis Baba] is certainly different from ings. Opinion 1700selected Laeocochlisas [lldica nana Bergh], so that the systematic the correct original spelling and position of the latter according to its exter- Laiocochliinae must be corrected to nal or internal shell can only be settled by Laeocochlidinae. new material of lldica nana. If this species had an inner shell, Lapinura would be the Article 29 statesthat: "Afamily-group name onlyruncinaceanwithanoutershell, andthe is formed by adding to the stem ofthe name familywould haveto be called Lapinuridae". ofthe type genus [Art. 29.3], or to the entire UnderArt. 15.1, Lapinuridae Er. &Ev. Marcus, nameofthetypegenus [Art. 55.3], a suffix as 1970, is notavailable name. specified inArticle 29.2" [Art. 29.1]. The stem of the names of type genera is FormationofNames determined byArt. 29.3 in accordancewiththe rules ofLatin grammar. The first, second and Articles 25-34determinetheformation and third editions ofthe Code ruled that a family- treatment of names. Ofspecific relevance to group namewith a wronglyformed stem was family-group names are Articles 29 [Forma- an incorrectoriginal spelling that mustbecor- tion offamily-group names] and 32 [Original rected. However, the 4"^ edition of the Code spellings]. nowrulesthat: Article 32.5.3statesthat: "Ifa spellingofafamily-groupnamewas not "A family-group name is an incorrect origi- formed in accordancewithArticle9.3 butis in nal spelling and must be corrected ifit prevailing usage, that spelling is to be main- 32.5.3.1. has an incorrectly formed suffix tained, whetherornotitistheoriginal spelling [Art. 29.2], or andwhetherornotitsderivationfromthename 32.5.3.2. isformedfroman unjustifiedemen- of the type genus is in accordance with the dation of a generic name (unless the unjusti- grammatical proceduresinArticles29.3.1 and fied emendation has become a replacement 29.3.2"[Art. 29.5]. name),or 32.5.3.3. isformedfrom an incorrectsubse- The purpose ofArt. 29.5 is to avoid destabi- quentspellingofagenericname [Art. 35.4.1]; lizing family-group names in current use by or requiring mandatorychangesforpurelygram- 32.5.3.4. isformed from one oftwo or more matical reasons. In the discussion preceding original spellings ofa genus-group name not the publication ofthe4th edition ofthe Code, selected bythe First Reviser[Art. 24.2.3]". theissueofadherencetotherulesofthe Latin "An incorrect original spelling has no sepa- grammar has seen the scientific community rate availability in the original form and can- split. Some scientists see this adherence as not, in that form, enter into homonymy or be partofthescholarshipoftheirprofession, oth- used as a replacement name" [Art. 32.4]. ers see it as an outdated remnant of the ep- Examples: och when zoologists had training in Latin and The tribe rank name Glabrocingulides Gor- Greek. Although we have ourselves had that don & Yochelson, 1987, has an incorrectly training, we do not want to impose ourvision formed suffix and must be corrected to to the community ofgastropod systematists, Glabrocingulini. and we havefollowed the spiritofArt. 29. Ulti- Homalaxinae Cossmann, 1916, is formed mately, the question is whether we have sta- from Homalaxis P. Fischer, 1885, an unjus- bilityinthespelling ofgastropodfamily-group tified emendation of Omalaxis Deshayes, names, and whetherfollowing the "grammati- 1832. Homalaxinae is an incorrect original cal niceties" (Wheeler, 1990) in Article 29.3 spellingthatmustbecorrectedtoOmalaxinae. would do more harm than good. Itseemsthat Ferrussacia [note double r] is an incorrect thespelling ofgastropod family-group names subsequent spelling of Ferussacia Risso, isan issuethat hasattracted littleattention so 1826, [single r] (stem Ferussaci-) and farand, after conferring with a numberofcol- Ferrussacidae Bourguignat, 1883, is an in- leagues, we have concluded that for a vast correct original spelling that must be cor- majority ofthe names there is no such thing rectedto Ferussaciidae. asa"prevailing usage"thatshouldeventually NOMENCLÁTOROFGASTROPOD FAMILIES bemaintained againsttherulesofLatingram- Conversely, the rules of Latin and Greek mar. Many colleagues in fact suggested that grammar appear to have consistently been the present nomenclátor would probably be- ignoredintheformationoffamily-groupnames come the standard reference for gastropod derivingfromgenerawiththesuffix-opsisand family-group namesand thatoneofitsconse- -ptyx (or -ptyxis). Although the rules would quences would be precisely to settle such recommendfamily nameendings in -opseidae nomenclatural issues. Inthisnomenclátor,we and -ptychidae, respectively, the prevailing havebeenguided principallybyadherenceto usage are endings in -opsidae and -ptyxidae, the rulesofLatin grammar[Art. 29.3], except and we have notattempted to correctthis. wheresuch adherencewouldcontravenewith A special difficulty was encountered with the spiritofArt. 29.5. names ending in -on, or-ion, and that cannot We have also been guided by consistency. always easily be attributed to a recognizable We believe that consistently deriving family- Greek or Latin root. The original spellings of group names formed on genera with similar the family-group names formed on, e.g., endings offers advantages in memorizing the Bothriembryon, Cerion, Coelocion,Semperdón, names. For instance, it is easierto memorize and Sinumelon were Bothriembryontidae, that the family-group names formed on Cerionidae,Coelociontidae,Semperdoninae,and Choanopoma and Rhytidopoma are Choano- SiNUMELONiNAE,respectively.Therearegood,but poMATiNi and Rhytidopomatinae, rather than disputable, grammatical reasonstoarguethat Choanopomatini(correctlyformedoriginalspell- thecorrectlyformedspellingsunderArt.29.3.1 ing) and Rhytidopominae (incorrectly formed would be BoTHRiEMBRYiDAE, Ceriidae (and this original spelling). Similarly, Alcithoinae, spellingwasindeedused byH. B. Baker, 1957, Nectophyllirhoidae and Phylliroidae aregram- and H. Nordsieck, 1986b),Coelociidae(andthis matically correctly formed on Alcithoe, spelling was used by Nordsieck, 1986), Nectophyllirhoe and Phylliroe. As a conse- Semperdontinae,andSinumelinae,butthiswould quence, we have co0rrected Lysinoeinae and sometimesrunagainstArt. 29.5,whichrulesto OxYNOEiDAE, formod Lysinoe and Oxynoe, maintain currentspellings in prevailing usage. toLysinoinaeandOxynoidae. Cerionidaeisin prevailing usagewiththatspell- Wehavetabulatedthefonnationoffamily-group ing, but the other names have had only very names derived from the most commonly en- limited usage, and we have chosen to main- counteredendingsofagenericname(Table2). taintheoriginalspellings. TABLE2. Mostcommongastropodgenericsuffixesandtheformationofderivedfamily-groupnames. . BOUCHET&ROCROI 10 Examples: siderthattwo nominalfamily-groupnamesare The stem of the genus Petropoma Gabb, validwhen anotherauthormayconsiderthem 1877, is Petropomat- [Code, 3^*^ edition. Ap- the same taxon, with one name a junior syn- pendix D, Table 2], and Petropominae Cox, onym ofthe other. Taxonomical validity is not 1960, was, underthefirst, second and third determined bytheCodeand isnotconsidered editions of the Code, an incorrect original in this nomenclátor. spelling that was to be corrected to Nomenclaturalvalidityisadifferentissuethat Petropomatinae. It was so corrected by isdeterminedobjectivelybytheapplication of Hickman & McLean, 1990, and this is here the Code. Validity is determined by Art. 23 considered thecorrectspelling. [Principle of Priority] and 24 [Principle ofthe Semisinusinae p. Fischer & Crosse, 1891, is First Reviser], as well as parts ofArts. 35-41 formed on Semisinus P. Fischer, 1885, an [Family-Group Taxa and Names]. Of particu- unjustified emendation [Art. 32.5.3] of lar relevance to this nomenclátor are the fol- HemisinusSwainson, 1840. Semisinusinaeis lowingArticles. an incorrect original spelling that was cor- rected to Hemisinuinae byThiele, 1928. How- (1) "The name of a family-group taxon is in- ever, thestemofHemisinusis Hemisin-, not valid ifthe nameofitstypegenus is ajunior Hemisinu-, and underArt. 29.3 the family- homonym or has been suppressed by the group name formed from Hemisinus is Commission" [Art. 39]. Hemisininae. There are very few works that Examples: deal with the taxonomyofthis group ofgas- The name Polytropidae Koken, 1925, is in- tropods, and there is no "prevailing usage" valid because its type genus Polytropis de that would justify maintaining the spellings Koninck, 1881, is a junior homonym of Hemisinusinae or Hemisinuinae; we have thus Po/yirop/sSandberger, 1875. considered Hemisininae to be the correct The name Xerophilidae Mörch, 1864, is in- spelling. The author of Hemisininae is P. valid becauseitstypegenusXerophila Held, Fischer&Crosse, 1891 1838, has been placed by Opinion 431 on ThestemofthegenusMorumRöding, 1798, the Official Index of Rejected and Invalid is Mor- and the derived family-group name GenericNames in Zoology. should be Morinae. However, as there was already a family Moridae Goode & Bean, (2)"Whenthe nameofatypegenusofa nomi- 1896, based on the fish genus Mora Risso, nalfamily-grouptaxon isconsideredtobea 1826, Hughes&Emerson(1987)established juniorsynonymofthe nameofanothernomi- MoRUMiNAE from Morum. This was the right nal genus, the family group name is not to approach underArt. 29.6, and Moruminae is be replaced on that account alone" [Art. a correctspelling underArt. 29.1. 40.1]. However, under Art. 55.3.1, changing the Example: stem of an existing family-group name to Hinoide & Habe (1978) placed Pedumicra avoid homonymy can be done only by the Iredale & Laseron, 1957, in synonymy of Commission. Schileyko (1998 [in 1998- Parastrophia de Folin, 1869, and replaced 2003]) emended Buliminidae Kobelt, 1880 Pedumicrinae Iredale & Laseron, 1957, with (based on Buliminus Beck, 1837), to the newname Parastrophiinae. Thisreplace- BuLiMiNuiDAE to avoid homonymy with ment is unjustified under the Code and the BuliminidaeJones, 1875 (based on Bulimina nomenclaturally valid name of the family- d'Orbigny, 1826). This was not permissible group taxon containing Pedumicra and under the Code, and the case had to be Parastropfiiais Pedumicrinae. brought to the Commission for a ruling. Hausdorf(2001)petitionedtheCommission (3) "If, however, a family-group name was re- to that effect, and Opinion 2018 ruled placed before 1961 because of the syn- BuLiMiNusiDAE to bethe correct spelling. onymy ofthe type genus, the replacement name isto be maintained ifitis in prevailing Validity usage. A name maintained by virtue ofthis Article retains its own author but takes the Thetaxonomical validityofa nominal taxon precedence ofthe replaced name ofwhich is determined subjectively by the opinion of it isdeemed to bethe seniorsynonym" [Art. individual taxonomists. An author may con- 40.2].