Table Of Content)
Bol.Soc.Biol.Concepción,Chile.Tomo66,pp.113-118,1995.
FARTULUMMAGELLANICUM (PROSOBRANCHIA, CAECIDAE):ANEW
SPECIES FROMTHEMAGELLANIC PROVINCE
Fartulummagellanicum (Prosobranchia, Caecidae): unanueva
especieparalaProvinciaMagallánica
I.DIGERÓNIMO*,S.PRIVITERA*&C.VALDOVINOS*='
ABSTRACT RESUMEN
AnewspeciesofCaecidaeFartulummagellanicumspec. Se describe una nueva especie de Caecidae, Fartulum
nov.(Prosobranchia:Caecidae),sampledduringtheFirstItalian magellanicumspec.nov.(Prosobranchia:Caecidae),recolecta-
OthceeaBneoaggrlaepChhiacnnEexpleádrietaio(Pna(ci1f9i9c1O)cienatnh)eiMsahgeerleldaenscSrtriabietd.anTdhiisn ednadeulraEnstterelachPoridmeerMaaEgxapleldainceisónyOecneaenlógárreaafidcealICtaalniaalnaB(e1a9g9l1e
speciesisthesouthernmostrepresentativepresentlyknownfor (OcéanoPacífico),correspondiendoalrepresentantemásaus-
theCaecidae. traldelafamilia.
KEYWORDS;Gastropoda.Prosobranchia.Fartulum.New
species.MagellanicProvince.Chile.
INTRODUCTION centralChileancoasts;FartulummooreiMarineovich
1973fromIquique(NorthernChile;Lat.20°13' S;
The caecids are uncommon in deep water Long.70°10' W).Thesethreespeciesoccurinthe
environments.Mostofthehvingspeciespresently malacologicalPeruvianProvinceandarealltypical
occurinthemidlittoralandinfralittoralzone,while ofshallowwater(midlittoralandinfralittoralzone).
findings in the circalittoral zone are rarer. Two BeforethesefindingstheCaecidaefamilyhasbeen
generaandthree species belonging to this family recordedintheeastemPacificOcean,justsouthof
have been previously recorded from the Chilean the coast of Panamá. The species here described,
coasts:CaecumchilenseStuardo1962(Lat.36°46' instead, occurs both in the circalittoral and in the
S; Long. 73°12' W) and Caecum (Micranellum) epibathyal bottoms and it is the southernmost
subaustrale Stuardo 1970 from the northem and representativeoftheCaecidaefamilypresentlyknown.
*IstitutoPolicattedradiOceanologíaePaleoecologia(I.P.O.P.)CorsoItalia55,95129Catania, Italia.
**LaboratoriodeBiologíaAmbiental,CentroEULA-Chile,casilla156C,Concepción.
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Bol.Soc.Biol.Concepción,Chile.Tomo66, 1995
RESULTS 7 Paratypes of F. moorei n. 1592 from the
Natural History MuseumofLos Angeles County
FamilyCaecidae havebeenalsoexamined.
FartulumCarpenler, 1857
Fartulummagellanicumspec.nov. Description:Teleoconchcylindrical,moderately
(PíateI,Figs. 1 -5) curved,vitreousorlightlyopaqueinlessfreshshells.
Undertheopticalmicroscope,surfaceseemsentirely
Material: The description is based on the smooth, with less distinct annular growth striae.
specimenscollectedduringtheFirstOceanographic Using the SEM these striae are rather thick,
ItalianExpedition(1991)alongthe570kmofthe irregularlydistancedandlittleengraved.Aperture
MagellanStraitandintheáreaoftheBeagleChannel circular with a thin lip folded outwards. Septum
withtheRA'"Cariboo"and"OGSExplora". welldeveloped, obliqueangledtothebackofthe
shell.Máximumdiameter,ataperture,isconstantto
a) RA^ "Cariboo" (Van Veen Grab, 0.1 m-): middleoftheteleoconchwhiletheposteriordiameter
Stn, 1 (52°45' S;74°59'W),20specimensfroma isalwayssmaller.Operculumandsoftpartsnotknown.
sampleoforganogeniasandinfrontofthePacific
entranceoftheStraitofMagellan (depth 100m- Variability:Thedimensionalcharacteristicsof
CaboDeseado). alltheunbrokenspecimenscomingfrom4ofthe5
sampledstationsofoccurrence(Tab.I)wererecorded.
b) RA' "OGS Explora"(VanVeenGrab,0.1 Thespecimenshavealengthrangeincludedbetween
m-): Stn. 38(52°46' S;74°59' W),40specimens 0.85and2mm.Diameterataperturebetween0.15and
fromadepthofl05mandStn.39(52°17'S;74°25' 0.35mm.Thesevalúesareconstantalsoatthemiddle
W),1specimencomingfromadepthof125mfrom oftheteleoconch,whilethediameterattheposterior
samplesoforganogenicsandoffthePacificentrance endvariesbetween0.10and0.30mm.
oftheMagellan Strait; Stn. 11 (55°07' S; 65°55'
W), 10 specimens from samples of organogenic F.magellanicumspec.nov.hasanaveragelength
sandtakenfromadepthof 190mofftheeastem of1.33mm,meandiameterattheapertureis0.25mm
entranceofBeagleChannel;Stn. 11bis(55°13'S; and at the middle ofthe teleoconch is 0.24 mm,
66°00' W), 15 specimens from samples of whiletheseptalenddiameteris0.19mm.Themean
organogenicsandtakenfromadepthof245moff oftheratiobetweentheaperturediameterandthe
theeastementranceofBeagleChannel(Fig. 1). posteriorenddiameteris 1.16.
Figure1.PacificsectoroftheStraitofMagellanandtheCanalBeagleárea.Loeationofsamplingstations.
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Bol.Soc.Biol.Concepción,Chile.Tomo66,1995
TABLEI.Dimensionalfeatures(mm)ofFartulummagellamicumspec.nov.
SPECIES
Bol,Soc.Biol.Concepción,Chile.Tomo66,1995
Holotype: The holotype has a total length of 37°20'S(Stuardo1962;1970;Marincovich1973).
1.45 mm, aperture diameter of 0.25 mm, in the BetweenSanVicenteBayandtheGulfofArauco
middleoftheteleoconchof0.25mmandadiameter (personal data, unpublished), in substrata of
attheposteriorendof0.20mm.Allthespecimens organogenicsandincludedbetweenthelowintertidal
are deposited at the Museum of the Istituto and72mofdepth.C.(M.)subaustraleStuardois
Policattedra di Oceanologia e Paleoecologia of presently known forthe type locality (in frontof
Catania University. Holotype n. MI. 8.8.95; LosVilos;31°54'S;71°32'W),atadepthof10m
Paratypesstaz.1n.Ml/A;staz.38n.Ml/B;staz.11 onabottomoforganogenicsand. AlsoF. moorei
n.Ml/C;staz. 11 bisn.Ml/D. Marincovich,thespeciesthatforitsmorphological
characteristic is closer to F. magellanicum spec.
Typelocality:TypelocalityisStn. 1locatedon nov.,isknownonlyforthetypelocality(Iquique,
thecontinentalshelfoffthePacificentranceofthe 20°13'Sand70°10'W)inthelowintertidalzone.
MagellanStrait,offCaboDeseado(52°45' S;74°
59' W)atadepthof100m(Fig.l). Stuardo (1970) reports of the existence of
anotherspeciesofCaecumfromsouthernChile,
Affinity:BetweenthethreespeciesofChilean whosedescriptionwasexpectedwiththeresults
Caecidaepresentlyknown,theclosesttothespecies ofthe study ofProsobranch molluscs collected
here described is Fartuliim inoorei Marincovich. bytheLundExpeditioninChileduring 1948-49.
Boththespeciesarecharacterizedbyanapparently Theseresults,however,tilltodayareunpublished
smoothshell.TheseptumofF.mooreiisdepressed and it was not possible to trace the preserved
anditsmueroisanglednearly90°toright,whileF. material.
magellanicumspec.fwv.hasaslenderdome-shaped AllthespecimensofF.magellanicumspec.nov.
septum. The aperture is completely different, F. were found in a sediment of organogenic white
magellanicumspec.nov.hasafoldedouterlipwhich sand. This datum agrees with the endopsammic
isinsteadlackinginF.moorei.F.magellanicumspec. behaviourofthecaecidthatduetotheirdiminutive
nov. ismoreslenderthanF.moorei whichislarger. sizes, the slender form of the shell, the ciliar
movementthattheyhave,arestrictlysand-inhabiting
species. Observations made in the laboratory
DISCUSSION (Panetta, 1980) on living specimens of two
Mediterranean species showed that the Caecum
Fartulummagellanicumspec.nov.isprobably move with a surprising agility in the sediment,
the southernmost species ofthe Caecidae family feeding on unicellular organisms (diatomee) that
presently known for the Chilean coasts, its theygrazefromgrainsofsand.AmaudandPoizat
distributionaláreabeingincludedbetween52°and (1979)affirminastudymadeonthedistributionof
55°SandincludedintheMalacologicalMagellanic theCaecidaeintheGulfofMarseille(France)that
Province(Stuardo, 1964). this genera seems to prefer sandy bottoms
ThethreespeciesofCaecidaepresentlyknown particularly exposed to strong (medium-high)
for the Chilean coasts are distributed around the hydrodynamism.Theseecologicalconditionsseem
centralandnorthernpartofChileandalloccurin tobethesameasthosepresentonthebottomsofthe
the Peruvian Province. Morphometrical and Pacific shelf and the western threshold of the
geographicaldataaresuppliedinTab.II.C.chilense Magellan Strait and the eastem entrance of the
Stuardo is the more common species and has its BeagleChannel,wherethespecimensherestudied
distributionaláreaincludedbetween 12°30' Sand werefound.Thisfactseemstobestrengthenedby
TABLEII.FeaturesoftheCaecidaespeciesfromthechileancoast(dimensióninmm).
TYPELOCALin DEPTH SEDIMENT BIOGEOGRAPHICALLATITUDINAL
PROVINCE RANGE
length diara.> Mid-Teleoc. d¡am.<
CaecumchilenseSTUARDO 1.98 0.49
Corara(M.)sutosíra/eSTUARDO2.26
FaniilmmooreiMARINCOVICH 1.55
Fartulummagellamcumspec.nov. 1.45
Bol.Soc.Biol.Concepción,Chile.Tomo66,1995
PLATEI.Fig.1.HolotypeofFartuluminagellanicumspec.nov.,offCaboDeseado(PacificOcean)Stn.1;100metres.Fig.2.Paratypeof
F. magellanicumspec.nov.,Stn.1;100metres.Fig.3.Youngshellwhichstillretainsitsinitialspiralcoil.Fig.4.Holotype:detallofthe
shapeoftheseptum.Fig.5.Holotype:detailoftheaperture,outerlipandsculpture.Fig.6,ParatypeofF.mooreiMarincovichfromIquique
(Chile).Fig.7.Caeciim(Micranelliim)subaustraleStuardofromSanVicenteBay(Chile).Fig.8.CaecumchilenseStuardo,reproduction
oftheholotypefromStuardo(1970).
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Bol.Soc.Biol.Concepción,Chile.Tomo66,1995
ACKNOWLEDGEMENTS
the condition of general freshness of shells that
indicate a minimum incidence of transpon. The
three species of Caecid known for the central- WearegratefultoDr.LouieMarincovichand
northemChileancoastsprefercoarseorganogenic Dr. James McLean curator ofthe Malacological
sandy beach environments with strong médium Section of the Natural History Museum of Los
hydrodynamism and a constant current on the AngelesCountyforkindhelpandforhavingsentus
bottom. someparatypesoíF.moorei.Wewanttothankalso
Thebathymetricdistributionoff.magellanicum Prof.AntonioBrambati,Prof.NevioPuglieseand
spec.nov. isbetweentheouterpartofthecontinen- Dr. Giorgio Fontolan ofthe Institute ofGeology
talshelfandtheupperpartofthecontinentalslope andPaleontologyoftheUniversityofTrieste,for
between 100 and 245 mofdepth. The sediments havingsentthesedimentsoftheexpeditionofthe
where the species has been found are typically RA' "OGS Explora"; Mr. Orazio Torrisi of the
sandyorganogenicbottoms(médiumcoarsesand), InternationalInstituteofVolcanologyofCataniafor
in relation with the medium-strong flooding and theSEMphotos.
ebbing currents that are present in the eastem PNRA Biological Oceanographic sector,
entrance of Beagle Channel and in the western ProgrammeonBenthicCommunities,UnitofCatania,
entranceofMagellanStrait. ResponsibleProf.S.DiGerónimo,Paper26.
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