A new Calliostoma species (Gastropoda : Calliostomatidae) from Angola

2006·3.5 MB·English

by  Franck Boyer

©SociedadEspañoladeMalacología Iberus,24 (2): 55-59,2006
A new Calliostoma species (Gastropoda: Calliostomatidae)
fromAngola
Unanuevaespeciede Calliostoma(Gastropoda: Calliostomatidae) de
Angola
FranckBOYER*
Recibidoel22-XI-2005.Aceptadoel7-V-2006
ABSTRACT
AsmalltrochoideanspeciesfromsouthernAngola ¡sdescribedasCalliostoma(Fautor) fer-
nandesisp. nov. No comparable species is known from trie WestAfrican Province, and
onlyonecomparablespecies is known from theCaribbean. Thesubgeneric placementin
FautorIredale, 1924 is based on recent revisions made aboutsimilar species from the
SouthwestPacific,towhichthenewAngolanspeciesseemstobecloselyrelated.
RESUMEN
Se describe como Calliostoma (Fautor) fernandesisp. nov. una pequeña especie de tro-
quoideo del surdeAngola. No se conoce ninguna especie comparable en la provincia
Oeste-Africana y tan solo una especie comparable es conocida en el Caribe. La asi-
gnación subgenérica en Fautor Iredale, 1924 se apoya en revisiones recientes de
especies similares del Pacífico suroeste, con las que la nueva especie angoleña parece
estarestrechamenterelacionada.
KEYWORDS:Calliostomatidae,Calliostoma,Fautor,Angola,WestÁfrica,SouthwestPacific.
PALABRASCLAVE:Calliostomatidae,Calliostoma,Fautor,Angola,Áfricaoccidental,Pacíficosuroeste.
INTRODUCTION
The specific diversity of tro- Jujubinus. A few Lusitanian tro-
choideanslivingattheinfralittoraland choideansreachthenortherntipofthe
circalittoral levéis ofthe WestAfrican WestAfricanProvince,principallythe
Provinceisknowntobeverypoor,com- PeninsulaofCapVert-Senegalandthe
paredtootherintertropicalprovincesas Cape Verde Archipelago, whereas the
wellastotheneighbouringtempérate rest of the province almost devoid of
Lusitanian Province which shelters, trochoideanspecies.
despite its smaller área, a noticeably Asaconfirmationofthis situation,
highernumberoftrochoideanspecies. the description of new trochoidean
Thescarcityoftrochoideanspecies speciesfromoffWestÁfricaremainsan
offWestÁfricaisnotedforallthetro- uncommonoccurrence,despiteimpor-
choidean groups, including groups tantprogressintheinventoryandstudy
well-representedwithintheLusitanian ofthe molluscan fauna ofthis marine
ProvincesuchasCalliostoma,Gibbulaor provinceforthelast25years. In1991,
*110,cheminduMaraisduSouci,93270Sievran,rranee.
55
Iberas,24 (2),2006
gofasdescribedasnewJujubinusfulgor luscaconstitutedbyPeterRyalloverthe
fronroffAngola(morerecentlycollected last25years.Characterizedbyaconical
also off Ghana and off Sao Tomé); in shell with tan ground and few strong
1993,RubioandSalazardescribedas cordsbearingbigroundednodules,this
new Calliostoma hernandezi from off calliostomatidspeciesisnotrecordedin
GuineaConakry (saidtorangealsooff theliteratureanditwasnotobservedin
SenegalandoffGabon);in2001,Rolan other public or private collections,
and Templado described as new includingsamplingsmadeinAngolaby
Gibbulaverdensis,G.sementisandG.clan- SergeGofas(MNHNgeneralcollection)
destina,togetherwithJujubinusrubioi,all andEmilioRolan(privatecollection).
fromtheCapeVerdeArchipelago. This calliostomatid species is
Asmalllotofshellsofadistinctive, described hereunder as new. On the
tinycalliostomatidspeciesfromsouth- basisoftherecentworksofMarshall
ernAngola (SantaMariaBay,southern (1995)andVilvens(2005)aboutCallios-
coast of the Benguela Province), col- toma species from deep water of the
lectedbyFranciscoFernandesinMarch Southwest Pacific, our new species is
1983,hasbeenstudiedintheimportant includedinthesubgenusFautorIredale,
collectionofWestAfricanmarinemol- 1924.
RESULTS
SuperfamilyTrochoideaRafinesque,1815
FamilyCalliostomatidaeThiele,1924
SubfamilyCalliostomatinaeThiele,1924
TribeCalliostomatiniThiele,1924
GenusCalliostomaSwainson,1840
Typespecies:TrochusconulusLinnaeus,1758(bys.d.Herrmannsen,1846).Recent,Mediter-
raneanSea.
SubgenusFautorIredale,1924
Type-species:ZiziphinuscomptusA.Adams,1855(byo.d.).Recent,southernAustralia.
Calliostoma(Fautor)fernandesisp.nov.(Figs.2-10)
Typematerial:HolotypeMuséumnationald'Histoirenaturelle(MNHN-Paris):adultspecimen
(6.00mm)(Figs.2-6),paratypen°lF.Boyercollection:adultspecimen(6.10mm)(Figs.7-9),paratypes
n°2-7P.Ryallcollection:1adultspecimen(7.14mm)and5juvenilespecimens.Allfromthetype
locality.
Typelocality:SantaMariaBay,BenguelaProvince,southernAngola,in1-2m.
Etymology:FromFranciscoFernandes,keencollectorandstudentfromLuandawhohighlycon-
tributedtotheincreaseofknowledgeaboutthemolluscanfaunaofAngolainthelateXX century.
Description:Holotype(Figs.2-6).Shell fíatsided,lastwhorlflaring,itssubsutural
small for the genus (6.00 x 4.85 mm), zoneslightlydepressed,itsuppersideless
imperforate,conical,spireratherhigh, obliquethanthesidesofthespirewhorls,
heightabout1.2xwidth,about3.2xhigher itsperipheralzonerounded.Fourthick
thanaperture,spireangleabout40°.Pro- spiralcordsoneachwhorl,eachspiral
toconchbulging, looking as a double- cordcoveredbystrongsubequalgranules,
bump,ofabout1.25whorls.Teleoconch sizeoftheroundedgranulesincreasing
of7whorls,apexstepped,spirewhorls fromtheposteriortotheanteriorpartof
56
BOYER:AnewCalliostomaspecies(Gastropoda:Calliostomatidae)fromAngola
lFiiogsutroema1.{JFuajuutboir)nufsefrunlagnodresGiofsap.s,no1v9.,91S,anStaantMaaMrairaiBaayB,ayA,ngAonlgao.la2,-66:.4h0olmomty,peFBMCN.HFNig,ure6s.020-1m0.m;Ca7l--
9:paratypen°l,6.10mm,F.Boyercollection;10:protoconchofparatypen°l,width:300um.
Figura1.Jujubinusfulgor Gofas, 1991, SantaMariaBay,Angola, 6.40mm, FBC Figuras2-10.
Calliostoma(Fautor)fernandesisp.nov.,SantaMariaBay,Angola.2-6:holotypeMNHN,6.00mm;
7-9:paratypen°l,6.10mm,FBoyercollection;10:protoconchofparatypen°l,width:300fim.
57
Iberus,24 (2),2006
thewhorl,granúlatespiralcordsseparated Withthelimitedamountofmaterial
bydeep,wideintervals. Eightsmooth athand,shellmorphologyofthespecies
spiralcordsonthebase. isconsideredtoberathervariable.Com-
Aperturesubquadrate,palataledge paredtotheholotype,theprotoconchof
elliptic,parietaledgestraight,subhori- paratypen°l ismorebulging,theshell
zontal, columellar edge subvertical, outline is moreslender,and thespiral
slightly sinuous, base weakly convex. cords of the base are more numerous
Groundcolourlighttan,decoratedwith (compare Figures 2, 3 and 6 with
lighthoney-brownmottling. Figures7-9).
Operculum small, subcircular, Calliostomafernandesi sp. nov. was
smooth,yellowish. collectedinsyntopywiththedistinctive
Animalandradulaunknown. Jujubinus fulgor Gofas, 1991 (Fig. 1),
Distribution: The species is only whichdiffersfromC.fernandesiinmany
knownfromthetypelocality. shell features,especiallyinits smooth
Remarks:Theprotoconchofparatype reddishprotoconch,thestrongerbasal
n°l (Figs.8,10),lesserodedthanthatof cords and more finely beaded upper
theholotype,iswhitishandshowsahon- cords of its whorls, its more convex
eycombed microsculpture. Two short base,itsmoreverticalcolumellarborder,
spiralsegmentsliejustaftertheproto- its pearly aperture and its more con-
conch whorl: each of these segments trasted colour pattern of harsh white
beginswithacoarseaxialfoldandhasa patchesonadeepredground.Noother
microsculpturemadeof4to5spacedfine calliostomatidspeciesisrecordedfrom
spiralcords. theinfralittoralofsouthernAngola.
DISCUSSION
TheplacementofC.fernandesiwithin However,onthewhole,C.fernandesi
theCalliostomatidaeisprincipallybased looksmoresimilartoaseriesofspecies
onthehoneycombpatternofprotoconch fromdeeperreeflevéisandfromupper
microsculpture,combinedtoapostlarval bathyaloftheSouthwestPacific,placed
sculpture made of 2 distinctive spiral byrecentauthorsinthesubgenusFautor
segments at the top of the teleoconch Iredale,1924(Marshall,1995;Vilvens,
(aboutl/iwhorl).These2featuresare 2005).
typicaloftheCalliostomatidae. Marshall(1995)justgives"thenar-
As faras theAtlantic fauna is con- rower,morefinelybeadedspiralcords"
cerned,C.fernandesiiscomparabletoC. asdistinctivefeaturesofFautorcompared
fascinansSchwengelandMcGinty, 1942 toCalliostoma(s.str.),butheconsidersthat
(ABbott,1974:43),distributedatcircalit- "thetwogroupsexhibitadistinctivemo-
torallevéisfromFloridatoMéxicoand saiccombinationofcharacterstatesthat
showingasimilarunperforateshellwith isdifficulttoobjectivelyquantifyorde-
thesamegeneraloutlineandspireangle, scribe".Despitethelimitedvaluéofthis
aboutthesamenumberofspiralcordson argument,andgivingtheprecisiónthat
the whorls and on the base, the same Fautoris"almostcertainlypolyphyletic",
patternofdecoration(whitegroundwith Marshall(1995)preferstouseprovi-
reddishbrownmottling).TheshellofC. sionallyFautorasapertinentsubgenusof
fascinansishoweverlarger(12-13mm), Calliostoma.OutoftheNewCaledonian
theperipheryofthelastwhorlissharply range,Marshall(1995)proposestoplace
carinate, the aperture is more losangic inthesubgenusFautorsixotherIndo-Pa-
withafíatbase,thebeadsonthespiral cificspecies,andwithmorereservation
cordsofthewhorlsarecoarser,theinter- theeasternAtlantic(mostlyLusitanian)
valsbetweenthesespiralcordsarenar- C.lithocolletumDautzenberg,1925.
rowerandlessdeep,andthespiralcords C.fernandesi resembles more espe-
ofthebasearefinelybeaded. ciallytheSouthwestPacific species C.
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BOYER:AnewCalliostomaspecies(Gastropoda:Calliostomatidae)fromAngola
houbrickiMarshall,1995(NewCaledonia tothesubgenusFautor, whereasall the
and Vanuatu), C. metivieri Marshall, otherAtlanticand Indo-Pacificspecies
1995 (New Caledonia) and C. strobilos attributabletothissubgenus were col-
Vilvens,2005(Fiji),allshowingthesame lectedindeepwater.
generalshelloutlinewithaboutseven Likemanyotherspeciesin various
whorls of teleoconch, a comparable molluscanfamilies, C.fernandesican be
macrosculptureandasimilarpatternof interpretedasarelictspeciessurviving
decoration. The shell ofC. houbrickiis inshallowwatersoftheAngolanrelict
closertotheoneofC.fernandesibecause pocket (Gofas, Pinto Afonso and
ofitssmallsize(about10-11mm),butit Brandáo,1985),whileotherrepresenta-
differs by its smaller protoconch, its tivesofitssubgenuswentextinctappar-
steppedwhorlsbearingaboutoneaddi- ently in all others places off Western
tionalspiralcord,thethreeuppermost África and survived only through
cordsbeingmuchthinner,thegranules patchy settlements at deep levéis in
beinglessprotruding,almostindistinct, otherbiogeographicmarineprovinces.
thebasemoreconvexwiththickergran-
ulóse spiral cords, the aperture more
ACKNOWLEDGEMENTS
losangic,ratherlikeinC.fascinans.
C.metivieriandC.strobilosbothshow
aroundedperipheralpartofthelastwhorl IamindebtedtoPeterRyall(Maria
similartotheonefoundinC.fernandesi, Rain,Austria)forloaningthetypemate-
buttheirapertureismoreextendeddown- rialforstudy,toSergeGofas(University
wardsandrightwards.Thelarge-sized ofMálaga)andtotheanonymousrefer-
shell ofC. metivieri (16-17mm) shows eesforvaluableremarksonthemanu-
abouttensubequalnarrowerspiralcords script,toJoséHernández(Galdar,Gran
oneachwhorl,separatedbywiderinter- Canaria) for performing the colour
valsandbearingsmallerandmorenumer- photos, to Emilio Rolan (Vigo, Spain)
ousgranules.Thebaseispartiallyperfó- andtoJesúsMéndez (Vigo,Spain) for
rate.Themedium-sizedshellofC.strobi- the SEM photography made at the
los(13-15mm)hasalessproducedspire Centro de Apoyo Científico y Tec-
anditbears7-8subequalstrongspiral nológicoalaInvestigación(CACTI) of
cordsoneachspirewhorl,thecoarsegran- theUniversityofVigo,toAlainRobin
ulesonthesecordsbeinghoweverless (Le Mesnil-Saint-Denis, France) for
protrudingthaninC.fernandesi. arranging the digital píate, and to
C. fernandesi seems to be the solé Robert and Nicole Hasselot (Jouques,
speciesfromshallowwaterattributable France)fortypingoutthemanuscript.
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