Tanzartemon gen. nov., a new land snail genus (Gastropoda, Pulmonata, Streptaxidae) from Morogoro District, Tanzania

2011·2.7 MB·English

by  Tattersfield, Peter

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Tanzartemon gen. nov., a new land snail genus
(Gastropoda, Pulmonata, Streptaxidae)
from Morogoro District, Tanzania
Peter Tattersfield
DepartmentofBiodiversityandSystematicBiology,NationalMuseumofWales,CathaysPark,CardiffCF103NP,UK;[email protected]
[correspondingauthor]
& Ben Rowson
DepartmentofBiodiversityandSystematicBiology,NationalMuseumofWales,CathaysPark,CardiffCF103NP,UK
TanzartemonisdescribedasanewgenusintheStreptaxidae.Twospecies,T.seddonaeandT.mkungwensis,aredescribedfrom
sub-montaneforesthabitatintheUluguruMountainsandfromtheoutlyingpeakofMountMkungwe,MorogoroDistrict,
Tanzania.Thegenusischaracterisedbyitsgloboseordepressedgloboseshellmorphology,thepresenceintheshellapertureof 39
oneormoreparietaldenticlesandofseveralstrong,peglikedenticlesthatsitimmediatelyinsidetheperistomeonthebasal,
palatalorcolumellarmargins.Thegenitaliaarecharacterisedbythepresenceofapenialsheaththatenclosesthepenis,butdoes
notincorporatealoopofthevasdeferens.
ThespecimensdonotresembleanyknowngenusintheEastAfricanfaunabecauseofthecombinationoftheirgloboseshell
andstrongaperturaldentition.PossiblerelationshipswithothermorphologicallysimilarstreptaxidsknownfromtropicalWest
Africa,particularlyLamelligerAncey,1884,arediscussed,but,basedonshellmorphologyandgenitalanatomyweconcludethat
TanzartemonislikelytobeanEastAfricanendemicgenusthatisnotcloselyrelatedtoWestAfricanforms.Weconsideritlikely
thatTanzartemonhaseitherevolvedinsitufromanothermorphologicallydissimilarAfricanlineageorfromlineagesfound
otherwiseonlyinAsiaorSouthAmerica,and,assuch,itisofbiogeographicalinterest.
Keywords:Gastropoda,Streptaxidae,Tanzartemongen.nov.,taxonomy,EasternArcmountains,UluguruMountains,MountMkungwe,forest,Tanzania.
Introduction variousothergeneraorsubgenera.Richardson(1988)listed
atotalof102speciesinthegeneramostrelevanttothis
Small,axially-deviatedstreptaxidswithaperturaldenti- study,i.e.HaploptychiusMöllendorff,1905,Indoartemon
tionoccurintropicalWestAfrica,SouthAmerica,andAsia; Forcart,1946,OdontartemonPfeiffer,1856(ofwhichLamel-
theyarenotknowninMadagascar.AccordingtoGude liger,Ancey,1884,wasconsideredasynonym),Oophana
(1902),thereisnofossilrecordforthegroup,whichhave Ancey,1884,PerrottetiaKobelt,1905,andStreptartemon
variouslybeenassignedtoStreptaxisJ.Gray,1837,orto Kobelt,1905.Disagreementoverthetypespeciesofeach
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taxon(alternativesbeingfromdifferentcontinentsinsome height(mm);H,shellheight(mm).Forcollections:BMNH,
cases),widevariationinmorphology,andalackof NaturalHistoryMuseum,London,UK;MRAC,Musée
knowledgeofevolutionaryrelationshipsamongStreptaxi- Royaldel’AfriqueCentral,Tervuren,BelgiumNMT,
daehaveresultedinrapidlychangingclassificationsofthis NationalMuseumofTanzania,DaresSalaam,Tanzania;
group(e.g.Pfeiffer,1856;Ancey,1884;Tryon,1885;Thiele, NMW,NationalMuseumofWales,Cardiff,UK;.
1935[1992translation];Bequaert&Clench,1936;Van Thenumberofshellwhorlsarecountedusingthe
BenthemJutting,1954;Zilch,1960,Richardson,1988; methoddescribedinKerney&Cameron(1979)
Schileyko,2000).Worksprovidingrelevantanatomicaldata
arefew.Eachgenus’relationshiptoStreptaxis(whosetype Systematic descriptions
speciesistheBrazilianHelixcontusaFérussac,1820)isopen
toquestion.Streptaxiscontususislarge,onlymoderately FamilyStreptaxidae
deviatedandedentate,whiletheother(sub)generaare
foundedonsmaller,dentatespeciesthatrangefrom Tanzartemongen.nov.
moderatelytoverystronglydeviated.
TheonlyAfricantaxonamongtheseisLamelliger.There Tanzartemonischaracterisedbyitsgloboseordepressed
issomedisagreementoverthecircumscriptionofthisgenus globoseshellandthepresenceofstrongaperturaldentition
anditsrelationshipwithOdontartemonPfeiffer(nonKobelt, includingatleastoneparietallamellaandseveralstrong
1880).WechoosetoadopttheviewofBequaert&Clench denticlesonthepalatal,columellarorbasalmargins.The
(1936),Degner(1934),Thiele(1935)andAdam(1962b)in shellmaybeslightlyaxiallydistortedorundistorted.The
whichLamelligerisconsideredavalidgenus,ratherthan genitaliaarecharacterisedbythepresenceofapenialsheath
thatofSchileyko(2000),Baker(1928)andZilch(1961)who thatenclosesthepenis,butdoesnotincorporatealoopof
40 consideredLamelligeranobjectivejuniorsynonymof thevasdeferens.
OdontartemonPfeiffer.Thisdisputeisnomenclaturalrather Etymology:fromthecountryTanzaniaandtheGreek
thansystematic,so,thusrecognised,Lamelligercontainsthe masculinenoun‘artemon’,aprincipalpulleyorforesail,
samefourspecies:L.troberti(Petit,1841)(typespecies), usedasacomponentofseveralotherstreptaxidnames.
L.distorta(Jonas,inPhilippi,1843),L.maassiDegner,1934, Gender:masculine.
and,provisionally,anunnamedspeciesdescribedin Typespecies:T.seddonaespec.nov.
Schileyko(2000)asOdontartemon“sp.B”.AlthoughAdam Otherspecies:T.mkungwensisspec.nov.
(1962b)concludedthatL.distortawasnotaLamelliger,hedid
notassignittoanothergenus,soherewediscussitalong Tanzartemonseddonaespec.nov.(Figs1-4,6,8,11-15)
withtheotherthreetaxa.AllfourarestrictlyWestAfrican,
occurringinAngola,Guinea,Guinea-Bissau,Liberiaand Typematerial:Holotypeplus2paratypescollectedbyP.Tattersfield,
SierraLeone(Bequaert&Clench,1936),withL.distortaalso Z.Habibu,C.MichaelandlocalTanzanianassistantsfromTegetero
occurringinGhanaandIvoryCoast(Adam,1962b).The villageinJanuary1996bydirectsearching(Table1).Theholotype
remainingaxially-deviatedstreptaxidsofAfricaare (NMW.Z.1996.148.00027)isadeadshell.Paratypes1
assignedtothegenusGonaxisTaylor,1877,andtovarious (NMW.Z.1996.148.00028)and2(NMT)werecollectedalive;paratype2
othergeneraoftenconsideredsubgeneraofit.Allareeither isjuvenile.
edentateorhaveasingleparietaltooth(Bequaert&Clench,
1936). Typelocality:UluguruNorthForestReserve,UluguruMountains,
Thefollowingabbreviationsareused,forshells:d, MorogoroDistrict,MorogoroRegion,Tanzania.Location:6.94°S
aperturediameter(mm);Dmax,shelldiameter-majoraxis 37.69°E.Allspecimenswerecollectedfromleaflitterintall,largely
(mm);Dmin,shelldiameter-minoraxis(mm);h,aperture intactsub-montaneforestlyingonsteepandstronglyundulating
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topography,ontheeastsideoftheUluguruMountains,aboveTegetero betweenthem.Theribbinggraduallybecomesweakerafter
Mission,atanaltitudeofabout1500mabovesealevel.Annualrainfall whorl5¾andthebodywhorl(whorl6ofparatype)is
intheareaisestimatedas2900-4000mm/yearandthereisnomarked smoothandglossy.
dryseason.Furtherdetailsofthecollectinglocalityareprovidedin Theperistomeisdiscontinuousacrosstheparietalregion
Tattersfield(1999)andinLovett&Pócs(1993). althoughtheparietalareaisslightlythickenedandmarked
byaridgeintheshellthatdevelopsintoanelongated
Shell.−Adultshelldepressedglobular(Figs1-2)with5¾ parietallamellafurtherintotheaperture(seebelow).The
whorls(holotype).Slightlydistortedalongcolumellaraxis peristomeisstronglyreflectedtoformabroadlipthat
(byabout10°)andapparentlyasymmetricallycompressed extendsaroundallsectionsoftheapertureapartfromnear
betweenupperandbasalsurfaces.Thisasymmetryresults thejunctionoftheparietalandpalatalareaswheretheperis-
inanovaloutlinewhenviewedfromabove(Figs1-2),with tomeissharpandnotreflected.Theumbilicusissealed,
theapertureprojectingfurtherfromthecolumellaraxisthan remainingonlyasashallowdepression.Theapertureis
theoppositesideoftheshell.Thebodywhorlandpenulti- crescent-shapedwithsub-equalpalatalandbasalsections
matewhorlsarebothwidestneartheapertureandthe andashortercolumellarsection.Thefour-foldapertural
majoraxisoftheshellextendsthroughtheaperturalregion dentitionintheadultspecimensconsistsofthreedenticles
(Figs1-2).Whenviewedfrombelow,theprecedingwhorls thatsitimmediatelyinsidetheperistomeplusadeeper,
areentirelyobscuredbythebodywhorl,withnooverlap single,spiral,elongatedparietallamella.Therearetwo
evident. large,rounded,peg-likedenticlesonthebasalsectionand
Thebaseoftheshellissmoothandglossywithveryfaint oneonthepalatalmargin,whichallsitjustinsidelip;these
andratherirregularspiralstriaethatarevisibleunderhigh denticlesareabout0.3-0.5mmlong.Theinnerendofthe
magnificationonly.Theuppersurfaceoftheshellisalso parietallamellastartsapproximatelyoppositethepalatal
glossyandwhorls1,2and3aresmooth;extremelyfaint denticleandextendsforalengthofabout1.7mm,withthe 41
spiralscratchesremainonveryfreshshells(paratypes1and outerendfinishingjustoutsidetheplaneoftheaperture.
2).Whorls4-5¾haveregularlyspacedradialribsthatare Thereisafurthershort,linearswellingontheparietal
strongestnearthesutureandfadeonthelowerpartsofthe surfacedeeperwithintheaperture.Theonlyknownjuvenile
whorl.Theribsonwhorl4arelocallybeadedatintervals (Fig.3)isedentateandwithoutthereflectedlip,andhasan
approximatelyequaltothegapsbetweentheribs;these open,symmetricalumbilicus.
combinetointroduceaspiralelementintothesculpture. Shellmeasurements:SeeTable1.
Thewidthsoftheribsareapproximatelyequaltothegap Bodycolour.−Live-preservedadultspecimenmainly
palecream,withapalecream-yellowdigestivegland,anda
veryslightorangetingetotheoptictentacleretractor
Specimen Accession H Dmax Dmin h d Whorls
No. muscles.Thelive-preservedjuvenilespecimenissimilarly
Holotype NMW.Z.1996. 5.4 8.6 6.8 2.7 4.6 5¾ coloured,butthedigestiveglandislightbrown.
148.00027 Genitalia(Figs9-14).−Penisnotablylong(9.0mmina
Paratype1 NMW.Z.1996. 5.7 8.7 7.1 2.9 4.8 6 withdrawnstateor0.7whorls),tubular,withoutappen-
148.00028 dices.Thepenisissubstantiallyswollenbasallyandslightly
Paratype2 NMT 3.4 6.2 5.7 2.7 3.0 4¾ swollenapically,entirelyenclosedinathinsheath.The
(juvenile)
sheathiscontiguouswiththepenialretractorapicallyand
penialwallbasally,beingcrumpledorcreasedaroundthe
Table1.Accessionnumbers,shelldimensionsandnumberofwhorlsof apicalfifthofthepenis,andwithasecondsmallretractor
Tanzartemonseddonaegen.&spec.nov. musclearisingneartheatrium,attachedtothebodywall.
Vasdeferensflattened,free,andrelativelystraight,arising
Tattersfield, P. & Rowson,B.-Tanzartemongen.nov.(Streptaxidae)fromTanzania
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42
Figs1-4.Tanzartemonseddonaegen.&spec.nov.1,holotype(NMW.Z.1996.148.00027);2,Paratype1(NMW.Z.1996.148.00028);3,Paratype2,juvenile
(NMT);4,do,apexandsculpture.
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ratherbasallyfromtheprostate,taperingtowardsthepenis smooth,white,withsmallindistinctvesiclesvisible
andenteringthepenialsheathsubapically.Thevasdeferens throughout,andwithafewscatteredthinanchoringmuscle
isapparentlycontiguouswiththeapicalpartofpenisand strands.Anteriorductexitingglandsubapicallyandbend-
notclearlydemarcated.Thepenialretractorisshort, ingoveranteriorpartofgland;posteriorglandexitingjust
attachedtothecolumellarmuscle,andtheenteringpenial posteriortomidpointofgland.Bothductsroundednearest
sheathtoattachtoanapicalbendofthevasdeferens.The thegland,becomingflattenedandstretchednearerthebuc-
wallsofthepenisarethickerthanthoseofthesheath. calmass,butevenlythickthroughouttheirlength.
Interiorsurfaceofpenishasthreedistincttypesofsurface Radula(Fig.8).−Buccalmasslong(11.0mm),slender
gradingintooneanotherasfollows.Apicalpartofpenis(or (1.25mm).Radulaofapproximately65steeplyv-shaped
vasdeferens):indistinct,reticulateelasticsculptureof rows(angleupto45ocentrally),with23-28teethineach
incompletetransverseseptaeandlowscattered,scale-like half-row.Noevidenceofacentraltooth.Lateralteethslen-
sub-rectangularpads.Middlepartofpenis:low,indistinct, der,aculeate,flattened,decreasinginsizegraduallylaterally
longitudinalpilastersoccasionallyanastomosing.Basalpart withoutasharptransitiontomarginals.Innerlateralswith
ofpenis:regular,shallowrhombicdepressions,each longbasalplates,theendofwhichgivestheimpressionofa
containingalowcentrallongitudinalpadbearingasingle slightswellingabouttwo-thirdsofthewayalongthelength
chitinoushook;sculpturebecominglessregularandgrading ofthetoothwhenteetharedisplacedortransparent.
intoindistinct,irregularpilasterstowardsatrium.Hooks Etymology.−thespeciesisnamedinhonourofDrMary
small(0.04mmlong),orange-brown,simpleinform,little B.Seddon,inrecognitionofhercontributiontothedevelop-
recurved,withsub-circularbases.Totalnumberofhooksin mentofmalacologicalresearchcapacityinTanzania.
penis:about82(counted).Albumenglandshort,wedge-
shapedandwithauniformstructureofverysmall,indis- Tanzartemonmkungwensisspec.nov.(Figs5,7)
tinctvesiclesoracini.Hermaphrodicticductdiverticulum 43
(talon)enlarged,butcompactandconvoluted,nothidden Typematerial:Holotype(NMW.Z.2003.001.00003)plustwoparatypes
withinalbumengland.Bursacopulatrix(=gametolyticsacor (NMW.Z.2003.001.00004;NMT)collectedbyB.RowsonandC.Ngereza
spermatheca)small,oval,apparentlyempty,andattending bydirectsearching(Table2).Allmaterialwascollectedasdeadshells.
albumengland.Bursacopulatrixductveryslenderapically,
butsubstantiallywiderbasallyandexitingvaginaonlyjust Typelocality:MkungweCatchmentForestReserve,MorogoroDistrict,
belowthepointatwhichthevasdeferensleavesthe Tanzania.MkungweisanisolatedoutlieroftheUluguruMountains,
prostate.Oviductalglandflattened,broad,withaciniof whichliesabout20kmtotheeastofthemainUlugurumassif.Location:
oviductalglandperhapslargebutalmostindiscernible,the 6.90°E37.91°S.Allspecimenswerecollectedfromsub-montaneforestat
surfaceappearinguniform.Noeggsorembryosinoviduct. analtitudeofabout900mabovesealevel.Lovett&Pócs(1993)provide
Vaginabroadandmuscular,withratherthickwallsand furtherdetailsabouttheforesthabitatinMkungweCatchmentForest
withashortroundedpouchbasally.Interiorsurfaceof andestimaterainfallonthewettereasternandupperslopesoftheRe-
vaginaconsistingofelastic,anastomosinglongitudinal serveas1700-2900mm/yearwithmisteffectonthesummitandwithout
pilasters,withasinglelobe-likelongitudinalpilasterpartly amarkeddryseason.
occludinglumennearexitofbursacopulatrixduct.Interior
surfaceofbasalpouchreticulate,consistingofshallowsub- Shell.−Shellgloboseandsymmetricalwithwhorlsexpand-
rhombicdepressions. inguniformlywithoutaxialdistortion;whorls7(holotype).
Salivarygland(Fig.15).−Single,5.1mmlong,occupying Allspecimensarewornandretainlittleperiostracumbutthe
abouthalfawhorlinlength,taperingposteriorly,concave smallfragmentsthatremainareglossyandretainevidenceof
andoverlyingtheoesophagusonthecolumellarside,the finespiralmicroscultureonthebaseoftheshell;acoarser,ra-
anteriorpartcurvedslightlytowardsthecolumella.Surface dial,ribbedsculptureispresentontheuppersurface.
Tattersfield, P. & Rowson,B.-Tanzartemongen.nov.(Streptaxidae)fromTanzania
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Aperturecrescentshapedwithsub-equalcolumellar,basal
andpalatalsectionsthatareratherpoorlydefinedbecause
ofthecurvatureoftheperistome.Theshellsarecalcified
andtheperistomeappearstobecontinuousacrossthepari-
etalzone,whichisthickenedandridged.Theperistomeis
stronglyreflectedtoformalipthatextendsaroundall
sectionsoftheapertureapartfromacrosstheparietalzone
andaroundthejunctionoftheparietalandpalatalareas
whereitissharpandnotreflected.Theumbilicusissealed,
remainingonlyasashallowdepression.
Thesix-foldaperturaldentitionconsistsoffourdenticles
thatsitimmediatelyinsidetheperistomealongthebasal
andcolumellarmargins,andtwoelongatedparietal
lamellae.Thefourbasal/columellarprocessescomprise
threestrong(c.0.4-0.5mmlong)denticles–oneeachatthe
palatal/basalandcolumellar/basaljunctions,andthethirdin
thecentreofthebasalzone.Thefourthdenticleislocatedon
thecolumellaandismuchweaker.Theoutermostparietal
lamellaextendsbeyondtheplaneoftheperistomeanditsits
oppositethedenticleatthebasal/palataljunction;itisabout
2.8mminlengthandextendsaroundthespiralintothe
44 aperture.Thedeeperparietallamellaisshorter(about
0.8mmlong)andpegshaped,anditsitsatrightanglesto
thelongerlamella.
Shellmeasurements:SeeTable2.
Differentiation.−Thestrongaperturaldentitionand
generallygloboseshellshapeindicateastrongaffinitywith
T.seddonae.However,T.mkungwensismaybedistinguished
byitssymmetrical,uniformlyexpandingspireandabsence
ofsignificantaxialdistortion,thepresenceofasecondmore
deeplysetparietaldenticleandtheoccurrenceofathird,
weakdenticleonthecolumellarmarginoftheperistome.
Anatomy.−Notknown.
Etymology.−fromthetypelocality,MountMkungwe.
Fig.5.Tanzartemonmkungwensisgen.&spec.nov.,holotype
(NMW.Z.2003.001.00003).
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Comparisons Introduction).Lamelligerischaracterisedbyastrongcontin-
uousparietallamella,whichrunstovaryingdegreesonthe
Shellmorphology.−NeitherspeciesofTanzartemonisidenti- parietalsurfaceintotheshell.InL.maassi(paratypein
calwithanyAsianorSouthAmericanspeciesorgenus MRAC97344-97346,fromTammasadou,GuineeFrancaise)
knowntous,sowerestrictourshellcomparisonstoAfrican thelamellaextendsforaboutonequarterofawhorlfrom
taxa.AnatomicalinformationonStreptaxidaeismore theaperture.Thiscontinuousparietallamellamaybeho-
fragmentaryandhomoplasyinshellshapecommon,sowe mologouswiththeshortlamellaandslightareaofdeeper
makeanatomicalcomparisonswithbothAfricanandnon- thickeningpresentinT.seddonae,andthedoubleparietal
Africantaxa. dentitioninT.mkungwensis.However,incontrastto
ThedistortedshellofT.seddonaesuggestsanaffinity T.seddonae,theaperturesofjuvenileL.maassi(MRAC)are
withthestreptaxidgenusGonaxisTaylor,1877,whichis furnishedwithaparietallamella.
widespreadintheEastAfricanfauna.However,allthe TherearealsosimilaritieswithLamelligerinrespectof
speciesattributedbyVerdcourt(2006)toGonaxisandits thebasalandpalataldenticles.Lamelligertroberti(MRAC
subgeneraintheEastAfricanfaunaareedentateorhaveat 97349-97350det.DegnerfromBolahun,Liberia)hastwo
mostasingleweakparietaltooth,sothepresenceofthe denticles,whicharealmostfusedinsomespecimens,atthe
strongaperturaldentitioninTanzartemonservestodifferen- baseoftheaperturalliponthecolumellaoronthebasal
tiateitfromGonaxis.Likewise,noneoftheotherspeciescur- sectionoftheaperture(theapertureisroundedsothese
rentlyassignedtoGonaxisfromelsewhereinAfrica(e.g.by sectionsarenotwelldifferentiated).InL.maassi(specimens
Bequaert&Clench,1936;Adam,1962a,b)havedentition asabove)therearetwosimilardenticleswhichlieonthe
beyondasingleparietaltooth.AllAfricanstreptaxidswith columellarsection,andthereisalsoafurther(sometimes
undistorted,globoseordepressedgloboseshells(e.g. elongated)denticlelyingdeeperwithintheapertureonthe
TayloriaBourguignat,1889)areedentate,withtheexception palatalsurface;thisdenticleisassociatedwithadepression 45
oftheEastAfricanJuventigulellaTattersfield,1998.However, atthesamepositionontheoutsideoftheshell.Sometimes
shellsofJuventigulellaareotherwisequiteunlikethatof thereisafurthersmalldenticleatthesameposition,slightly
Tanzartemon,beingminute,stronglysculpturedandwith closertotheaperture.TheumbilicusofL.maassiisclosed,
differentdentition(Tattersfield,1998). butitisachinkinL.trobertiandopeninthethirdspecies
Inbeingbothstronglydentateanddistorted,Tanzartemon L.distortus(materialinBMNH).Fromthefiguresand
bearsaresemblanceonlytotheWestAfricanLamelliger(in- descriptiongivenbySchileyko(2000),Odontartemon“sp.B”
cludingL.distortaandOdontartemon“sp.B”ofSchileyko;see closelyresemblesL.maassi.
Theshellsofalltheabovespeciesaremoredistorted
alongthecolumellaraxisthanTanzartemon,totheextentthat
Specimen Accession H Dmax Dmin h d Whorls
No. theprecedingwhorlprojectsbeyondthebodywhorlwhen
Holotype NMW.Z.2003. 6.0 7.8 7.1 2.4 4.0 7 viewedfrombelow.InTanzartemon,theprecedingwhorlis
001.00003 entirelyobscuredbythebodywhorl.Intermsofshell
Paratype1 NMW.Z.2003. 6.1 8.4 7.5 2.3 4.1 7 surfacesculpture,theshellbaseandapicalwhorlsofboth
001.00004 maassiandtrobertiaresmoothbuttheotherwhorlsare
Paratype2 NMT 6.0 8.3 7.3 2.3 4.3 7 ribbed(weaklyintroberti).
Genitalanatomy.−Dataongenitalanatomywerecon-
sultedforthefollowingspeciesandsources(generafollow
Table2.Accessionnumbers,shelldimensionsandnumberofwhorlsof Richardson,1988,exceptwherenoted):Discartemonstenosto-
Tanzartemonmkungwensisgen.&spec.nov. musvanBenthemJutting,1954(Malaysia;Berry,1965);Hap-
loptychiussinensis(Gould,1856)(Vietnam;Schileyko,2000);
Tattersfield, P. & Rowson,B.-Tanzartemongen.nov.(Streptaxidae)fromTanzania
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Figs6-8.Tanzartemongen.nov.6,T.seddonaespec.nov.,paratype1(NMW.Z.1996.148.00028),aperture;7,T.mkungwensisspec.nov.,holotype(NMW.Z.
2003.001.00003),aperture;8,T.seddonaespec.nov.,paratype1(NMW.Z.1996.148.00028),half-rowsfrommedianpartofradula.
Hypselartemoncontusulus(Férussac,1827)(Brazil;Barbosaet recommendingthesplittingofgenera(Schileyko,2000;
al.,2002);Lamelligermaassi(Degner,1934)(Guinea;Degner, Rowson,2010);thisisevidentlyanimportantdifference.Ina
1934);Lamelligertroberti(Petit,1841)(Guinea/Liberia; largenumberofAfricanandothergenera,thepenialsheath
Degner,1934);Odontartemon(i.e.,Lamelliger)“sp.B”(Sierra enclosesaloopofthevasdeferens(seeSchileyko,2000)but
46 Leone;Schileyko,2000);OophanadiaphanopepleaVan thisisnotthecaseinT.seddonae.Secondly,penialhooksin
BenthemJutting,1954(Malaysia;Berry,1963);Oophana T.seddonaeoccurstrictlyinthebasalpartofthepenis,unlike
obtusa(Stoliczka,1871)(Burma/Myanmar;Blanford& thethreeLamelligerspecieswherehooksarescattered
Godwin-Austen,1908);Perrottetiagudei(Fulton,1915) throughout.Thirdly,thepenialretractorjoinsthecolumellar
(Vietnam;Schileyko,2000[treatedinStreptaxisbyRichard- muscleinT.seddonae,asitdoesinthemajorityofstrep-
son,1988]);Streptartemonglaber(Pfeiffer,1849)(Guyana; taxids.InthisitrecallsL.trobertiandL.maassi,butnotL.sp.
Schileyko,2000);andStreptartemonglabernormalis B.,whereitissaidtojointhebodywall(Schileyko,2000).
(Jousseaume,1889)(Venezuela;Baker,1925;1926).Dataon Theremaininganatomicallyknowntaxacitedabovehavea
other,moredissimilar,streptaxidgeneraarealsogivenby penialsheathcoveringsomeorallofthepenis(theexcep-
Degner,1934andSchileyko,2000inparticular.Inaddition,
oneofus(BR)hasdissectedmanyadditionalStreptaxidae
fromAfrica,Asia,SouthAmericaandtheIndianOcean Figs9-15.Tanzartemonseddonaegen.&spec.nov.,paratype1
(Rowson,2010). (NMW.Z.1996.148.00028).9,genitalia,dorsalview;10,penisandvagina,
Therearethreemaindifferencesbetweenthegenitaliaof ventralview;11,insideofvagina;12,insideofpenisandsheath;13,
Tanzartemonandthethreeanatomicallyknownspeciesof hooksandrhombicpadsfromatrialpartofpenis;14,hooksfromatrial
Lamelliger.Firstly,T.seddonaehasalongpenialsheath,unlike partofpenis;15,salivarygland.Scalebars1mm(9-13,15);0.1mm(14).
thethreeanatomicallyknownspeciesofLamelliger,inwhich Abbreviations:ag,albumengland;bc,bursacopulatrix;bd,bursaduct;
asheathisabsent(Degner,1934;Schileyko,2000).A fo,freeoviduct;hd,hermaphroditicglanddiverticulum;og,oviductal
variously-developedpenialsheathoccursinalltheother gland;pn,penis;pr,penialretractor;ps,penialsheath;sd,salivary
streptaxidscitedabove,aswellasmanyothers,thesheath glandduct;vd,vasdeferens;vg,vagina.
havingbeenusedasacharacterindefiningsubfamiliesand
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Tattersfield, P. & Rowson,B.-Tanzartemongen.nov.(Streptaxidae)fromTanzania
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tionbeingOo.obtusa,whosedescriptioninBlanford& evolvedinsitufromanothermorphologicallydissimilar
Godwin-Austen(1908)isnotdetailedenoughtobesure). Africanlineageorfromlineagesfoundotherwiseonlyin
ExceptinS.glabernormalis,thepenialretractorjoinsthe AsiaorSouthAmerica.TheEasternArcMountainforests,of
columellarmuscle.Allhavepenialhooksthroughoutthe whichthetypelocalitiesofbothTanzartemonspeciesforma
interior,exceptforOo.obtusa(againnodata)andfor part,arenowfamousfortheirhighlevelsofendemism,
D.stenostomus,whichlackshooksandhas“cornifiedridges” includingbothrecent,specioseradiationsandancientrelicts
andasingle“stylet”apically(Berry,1965).Althoughthere withdistantaffinities(Burgessetal.,2007).Intheabsenceof
areshellsimilaritiesbetweenthisspeciesandT.seddonae,the geneticdata,themorphologicaldistinctnessthatleadsusto
penisofD.stenostomusisquitedifferent.Eachoftheremain- proposeanewgenussuggestsTanzartemonisanexampleof
ingspecieshasotherapparentlymoreminorunique thelatter.
features(seeSchileyko,2000),asdoesT.seddonae,butAsian,
SouthAmericanandAfricanspeciesallsharethesameplan. Acknowledgements
Insummary,anatomicalfeaturesdolittletosuggestan
especiallycloserelationshipbetweenT.seddonaeandany WethankDrMarySeddonforassistanceduringfieldwork
onegenus,whileacloserelationshipwiththeAfrican andforcriticaldiscussionaboutthestatusofthesetaxa.
Lamelligerappearsparticularlyunlikely. FieldworkwassupportedbytheUKDarwinInitiativeand
Thesamepatternissuggestedbyradularcharacters. bygrantstoPTfromTheBritishEcologicalSociety,The
RadulardataareavailablefromH.contusulus,L.maassi, LinneanSocietyofLondonandThePeoplesTrustfor
L.troberti,Oo.obtusa,andS.glabernormalis,plusother EndangeredSpecies.ChristineNgerezaandotherstaffof
streptaxidsintheliteratureandrecentlyexaminedbyBR. theNationalMuseumsofTanzaniagaveinvaluable
ThetwoLamelligerspecieshaveanunusualradulawitha suppportandtheTanzaniaCommissionforScienceand
48 centraltoothandrelativelyfewenlargedinnerlateralsthat Technologygrantedpermissiontoundertakefieldworkand
rapidlychangeinsizetowardsthemarginalteeth.Asimilar researchinTanzania.TheTanzaniaDepartmentofForestry
patternisshownbytheSouthAmericanS.glabernormalis.In andBeekeeping,CatchmentForestry,andDistrictForestry
contrast,theshape,number,gradualchangeinsize,and Officersprovidedsupportandgavepermissiontoworkin
apparentabsenceofacentraltoothinT.seddonaeiscloserto theForestReserves.TegeteroMissionandthepeopleof
theotheraxiallydeviatedtaxastudiedbyThiele(1933) Tegeterovillageprovidedlocalsupportandassistance
andDegner(1934)thantoeitheroftheLamelligerspecies.As duringfieldworkinUluguruNorthForestReserve.Wealso
withgenitalanatomy,thetypeofradulaseeninT.seddonae thanktwoanonymousreviewersfortheircommentsand
appearstobearathergeneralone,occurringintheBurmese suggestionsonapreviousdraftofthemanuscript.
Oo.obtusaandtheSouthAmericanH.contusulus,aswellas
manyAfricanspeciesofGonaxis(s.s.ands.l.).Again,aclose
relationshipwithLamelligerisnotsupported. References
NothingcloselyresemblingLamelliger,oranyofthe
othergeneralistedabove,haspreviouslybeenrecorded Adam,W.,1962a.Etudessurlesmollusquesdel’AfriqueCentraleetdes
fromcentral,EastorsouthernAfrica,Madagascarorthe régionsvoisines.3.QuelquesespècespeuconnuesdeGonaxis.−
IndianOceanislands(tworecordsfor“Rodriguez”basedon Bulletindel’InstitutRoyaldesSciencesNaturellesdeBelgique38
theCumingcollectionhavingbeendismissedaserroneous (17):1-10,pl.1.
[Germain,1921;Griffiths&Florens,2006]).Herewepropose Adam,W.,1962b.Etudessurlesmollusquesdel’AfriqueCentraleetdes
thatshellandanatomicalfeaturessuggestTanzartemonisan régionsvoisines.4.ContributionàlaconnaissancedugenreLamel-
EastAfricanendemicgenusnotcloselyrelatedtoLamelliger. ligerAncey,1884.−Bulletindel’InstitutRoyaldesSciencesNa-
Assuchitisofsomebiogeographicalinterest,havingeither turellesdeBelgique38(21):1-11.
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