New data on Theba subdentata helicella (Wood, 1828) (Gastropoda, Helicidae) in Almeria (SE Spain)

2007·16.2 MB·English

by  Diego Moreno

©SociedadEspañoladeMalacologia Iberus,25 (1):89-113,2007
New data on Theba subdentata helicella (Wood, 1828)
(Gastropoda, Helicidae) inAlmería (SE Spain)
Nuevos datos sobre Theba subdentata helicella (Wood, 1828)
(Gastropoda, Helicidae) enAlmería (SEEspaña)
DiegoMORENO*andMaÁngelesRAMOS**
Recibidoel31-VII-2006.Aceptadoel10-V-2007
ABSTRACT
The distribution of Theba subdentata helicella (Wood, 1828) ¡n the Eastern partofthe
Almería Bayisstudied.Thispaperconfirmstheexistenceofrich populationsof Ts. helice-
lla ¡nhabiting the lowlands cióse to the sea, never reaching the surrounding mountains.
Informationonthehabitat,shellandgenitalsystemvariabilityisprovided.
Theshells showa characteristicallydepressed and sharply keeled shape, and are usually
whiteorwithalightbrowntoorangespiral band nearthecarina inall populationsexcept
in Amoladeraswatercourse (inside the Cabo de Gata-Níjar Natural Park). In this locality
there isa gradation from thetypical form toalmostglobularspecimenswith a veryslight
keel, nearlywanting,onlyvisibleonthelasthalfofthebodywhorl neartheaperture,simi-
larto T. s. dehnei(Rossmássler, 1846) from Morocco. These shells show basal bands or
blotchesthatremindthoseof Thebapisanapisana(O.F.Müller, 1774)or Ts. dehnei.
Thegenital system oftheAmoladeras population iscompared with those described for T
s. helicellay T. s. dehneifromMorocco, confirmingthatitsharesmorecharacterswiththe
firstsubespecies.Adiscriminantfunctionanalysisofshellscharactersmeasurementsoftwo
populationsof Ts. helicellaand T.p.pisanaallowedtodiscardthehypotesisofan hybrid
originoftheglobosespecimens.
Data on the presence and habitatofothergastropod species living with T s. helicella in
thestudyáreaareprovided.
RESUMEN
Seestudia la distribución de Thebasubdentatahelicella(Wood, 1828) en la mitad orien-
tal de la bahía de Almería, su principal área de presencia en Europa, confirmando la
existencia de poblacionesabundantesyaportando información sobreel habitat, lavaria-
bilidad de la concha, ysu aparatogenital. Esta subespeciesedistribuye por los terrenos
llanospróximosal marsin llegaraocuparlasmontañaspróximas.
En general, en todo el área de estudio las conchas de T s. helicellacorresponden a la
forma típica aquillada, aplanadaygeneralmentedecolorblancoocon una banda espi-
ral dorsal oscura, mientras queen la población deAmoladeras (dentro del Parque Natu-
ral deCabodeGata-Níjar), existeuna gradación desde la formatípica aotra globosay
ligeramente aquillada o sin quilla en la vuelta del cuerpo, similara la de Thebasubden-
tata dehnei(Rossmássler, 1846) de Marruecos. Ésta presenta distintos patrones de pig-
mentación, con varias bandas y manchas, que recuerdan a los de Thebapisanapisana
(O.F.Müller, 1774)o Ts. dehnei.
*Egmasa/ConsejeríadeMedioAmbiente,c/Marruecos33-bajo,04009,Almería(Spain)
**MuseoNacionaldeCienciasNaturales(CSIC),c/JoséGutiérrezAbascal2,28006,Madrid(Spain)
89
Iberus, 25 (1),2007
El sistema genital de la población deAmoladerassecompara con losdescritos para T. s.
helicelloy T. s. dehneideMarruecos, confirmando que comparte máscaracteres con los
de la primera subespecie. Un análisis discriminante de las medidas de la concha de dos
poblaciones de T. s. helicelloy las de T. p. pisaríapermite rechazar la hipótesisde hibri-
dacióncomoorigendelasformasglobosas.
Se incluyen datos de la presencia y habitat de las especies de gasterópodos terrestres
halladaseneláreadeestudioyquevivenensimpatríacon T. s. helicello.
KEYWORDS: Thebasubdentatahelicello., Helicidae,distribution,taxonomy,variability,faunistics,Cabode
Gata,Almería,Spain.
PALABRASCLAVE: Thebasubdentatal.ielicella, Helicidae,distribución, taxonomía,variabilidad, faunística,
CabodeGata,Almería,España.
INTRODUCTION
Thebasubdentata(Férussac,1821)isa cludedthatthispopulationhadproba-
polytypicspecieswithitsmainrangein blybeenintroduced inSpain and had
WesternMorocco.AccordingtoGitten- eventually become extinct. After that,
BERGER AND RlPKEN (1987), it ÍS an Puente, Altonaga, Unamuno and
extremelyvariablespeciesthat"...has Prieto (1994) found three specimens
beenratherarbitrarilysubdividedinto (oneadult,onesub-adultandonejuve-
fivesubspecies:T.s.subdentata(Férussac, nile) ofthis subspeciesatCerrillos,35
1821), T. s. helicella (Wood, 1828), T. s. kmwestofElAlquián,andprovideda
dehnei(Rossmássler,1846),T.s. meridion- drawing of the adult genital system.
alis (Sacchi, 1955) and T. s. legionaria These specimens confirmed the pres-
(Sacchi,1955)".Gradualvariationamong enceofT. s. helicellainEurope.Thefirst
subspecies has been described for recordofalivepopulationofT. s. heli-
several shell characters, apparently cella in El Alquián was reported by
relatedtohabitatvariation. Thebas.heli- MorenoandRamos(2000),whostated
cella lives in sand-dunes along the thattheEasternlimitofdistributionis
Moroccancoastinthenorthernpartof locatedinsidetheprotectedáreaofthe
itsrange.Itisknownfromc.30kmSof CabodeGata-NíjarNaturalPark.
NSafWi eoxftenAdgiandgirsou(tGhitwtaerndbetorgce.r35aknmd AraAufjteoratnhadt,AGlóvmaerze,zM(o2r00e1n)op,rRooploasne,d
Ripken, 1987; Gittenberger, Ripken the inclusión of this taxon in the
andBueno,1992).Thebas.helicellahasa National Red List of Endangered
characteristicallydepressedandsharply Species (CatálogoNacionaldeEspecies
keeled shell, although this character Amenazadas) as "Vulnerable". Later,
varies gradually from north to south, Menez (2006) provided some data on
shifting to more rounded in southern thehabitatand densityofthepopula-
specimens, such as T. s. dehnei, a sub- tionofT. s. helicella atRetamarand El
speciesthatinhabitsrockyáreas. Inter- Alquián(Almería).
medíateformshavebeenfoundinplaces In this paper we confirm the exis-
wheresand-dunesandrockyáreascon- tenceofanumerousandhealthypopu-
verge(GittenbergerandRipken,1987). lationinElAlquiánandextenditspre-
Gittenberger and Ripken (1987) viously known distribution to further
cRiMteNdHa sLaemipdleenof(AlT.tism.irhealicceollllaecitniotnh)e, áterresasanofdAclhmaerarcítaerPrvoavriinactei.onShtehlrlocuhgahroauct-
believed to origínatefrom ElAlquián, itsdistributionrangeinthestudyárea
Almería (Spain).After"...tryinginvain aredescribedandcomparedwiththose
toconfirmthisrecord",theauthorscon- ofthesympatricandcongenerictaxon
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MORENOANDRAMOS: Newdataon ThebasubdentatahelicellainAlmería
Thebapiscinapisaría (O.F. Müller, 1774). SerratadeNíjar,thevolcanicmountains
Forthefirsttime, thecharactersoíthe thatliebeforetheCabodeGata moun-
genitalsystemandtheirvariationsare tains,excludedinthepresentstudy.
describedforthepopulationoíT.s.heli- Shell measurements were obtained
cellainElAlquián. Theyarecompared withacalliperorusingthemicrometric
withtheMoroccanpopulationsoíT. s. ocularofthestereomicroscope. Forthe
helicellaandwiththecloselyrelatedsub- estimationofthenumberofshellwhorls
speciesT.s.dehnei,fromdatapublished themethodofVerduin(1976)wasused.
intheliterature(Hesse,1915).Ecological Shellswerefirstcleanedwithultrasound
dataarealsoprovidedwithconsidera- andtheperiostracumwasremovedby
tions ofthe conservation status ofthe immersionina5%solutionofsodium
subspecies in Spain. Other species of hypochlorite. With an Environmental
terrestrialmolluscsarealsocitedforthe ScanningElectronMicroscope (ESEM)
studyárea. PhilipsQuanta200SEMinlowvacuum
mode,shellswerestudiedwithoutgold
coating and photomicrographs were
MATERIALSANDMETHODS taken. Foranatomicalstudies,animáis
werefirstimmersedinwateruntildeath
WeexploredtheentireEasternzone andthenpreservedin70%ethanol.Dis-
oftheAlmeríaBay,betweentheAlmería sectionsweremadeinwateroncorkor
airport(ElAlquián),andCabodeGata on a Petri dish with a black layer of
mountains (excluded). The first live paraffin,waxandcoal(Davis, 1967).A
populationofT.s.helicellawasfoundin StemiSV8Zeissstereomicroscopewas
March1994inElAlquián.Afterthat,the used for observations and measure-
áreawasexploredlookingforT. s. heli- ments.Genitalphotographsweretaken
cellainordertoconfirmthelimitsofits withanOlympus SZH10 stereomicro-
distributionárea.Allthedifferentgas- scope. Anatomical illustrations were
tropodspeciesobservedwerecollected. basedoncamera-lucidadrawings.
Theabundanceofallspecieswasesti-
mated from the number of specimens Abbreviations used in text, tables
and/or fresh shells collected or andfiguresare:
observed, during the sampling effort, Shellmeasurements.AH: aperture
about10-15minutes,ineachlocality. height,AW: aperturewidth(máximum
Thesamplinglocalities(TableI,Fig. diameteroftheaperture),NSW:number
1)wereallinAlmeríaprovince,andare ofshellwhorls,SH:shellheight,SW:shell
listedfromWesttoEastinTableI.UTM width,UD:umbilicusdiameter,WBW:
coordinates, sampling dates, a brief widthofthebodywhorl.Measuredshells
descriptionofthesubstratumanddomi- andmeasurementsareinTableIII.
nloacnaltitvye.gUetTaMticoonoradrienaptreosviwdeerdeofbortaeiancehd bursGaenictoaplulsaytsrtiexm,.dadg::adlibstuamlepnagrltanodf,tbhee:
from the official Army Geographical bursacopulatrixduct,di: diverticulum,
Servicemap(1:50.000series). ds: dartsac,e: epiphallus (frompenis
Thelittoralofthestudyáreaischar- retractormuscletovasdeferens),f: fla-
acterized by sandy beaches, dunes, gellum,fod:freeoviduct,hd:hermaph-
"ramblas" (seasonal watercourses), a roditeduct,hg:hermaphroditegland,mg:
vegetationcomprisedofmostlyAfrican mucosaeglands,p:penis,pd:proximal
species (asZiziphus lotus),manmd asemi- partofthebursacopulatrixduct,pp:penis
aridclimate,withonly200 ofrain- papilla,prm:penisretractormuscle,rp:
fall eachyear. Upstream, from El Bar- radialpleats,v:vagina,vd:vasdeferens,
ranquete (Rambla del Hacho, on its vs:vesículaseminalis,Measuredorgans
rightbank), therearerockyáreaswith andmeasurementsareinTableIV.
m
conglomerates at 60 altitude above Collectors.Samplingandfieldobser-
sealevel(thehighestpointamongthe vationswerecarriedoutbyD.Moreno
studiedlocalities).Fromherebeginsthe andN.Martínbetween1994and2006.
91
Iberus,25 (1),2007
TableI.Samplinglocalitiesinthestudyárea,fromwesttoeast,withUTMcoordinates,collectioo
dates,abriefdescripciónofthesubstratumanddominanrvegetation.AlllocalitiesinAlmeríaPro-
vince.Localities7,8, 10-23and25-28areinsidetheCabodeGata-NíjarNatural Park. "Rambla'
=seasonalwatercourse.
N° Localities UTM Collectiondates
1 TorredelPerdigal,ElAlquián 30SWF563777 8-111-1997,10-111-1997
2 PlayodeElAlquián,fishingbootsorea 30SWF563777 8-111-1997,10-111-1997
3 DunesbetweenElAlquián-CasaFuerte 30SWF585775 8-111-1997
4 CasoFuerte,ElAlquián 30SWF602771 31-111-1994,15-1-1995,10-111-1996,
8-111-1997,l-V-2002,20-VI-2002
5 CortijoelPino,ElToyo 30SWF607783 23-XI-2000
6 UrbanizacióndeRetamar 30SWF616785 15-1-1995
7 RambladelAgua,Retamar 30SWF620763 15-1-1995,5-IX-l997,12-IX-l997
8 ForesttrailtoTorregarcía,westernárea 30SWF633761 15-1-1995,8-111-1997,5-V-2006
9 CortijodelRetomar 30SWF633789 7-V-2006
10 ForesttrailtoTorregarcía,easternárea 30SWF632758 8-111-1997
11 RambladeAmoladeras,rightbank 30SWF638754 5-X-2001,19-VI-2002,2-IX-2002
12 PlayadeAmoladeras 30SWF643748 22-IV-2002
13 BunkerofAmoladeras 30SWF65174 13-IV-1994,22-IV-2002
14 OrnithologicalRefugeofAmoladerasandViewpoint 30SWF654762 21-IV-2000,4-IX-2003,6-XI-2004
15 Amoladeras,Beacon 30SWF655768 4-IX-2003
16 Amoladeras,1kmupstreamfromOrnithologicalRefuge 30SWF656776 4-IX-2003
17 PlayadeElCharco 30SWF660732 22-IV-2002
18 AmoladerasInterpretationCenter 30SWF666753 19-1X1996
19 RightbankofElCharcolagoon 30SWF664730 22-IV-2002,l-V-2002
20 LeftbankofElCharcolagoon 30SWF670730 10-IV-2002,6-VI-2002,l-VIII-2002
21 Mazarulleque 30SWF667742 12-1-2002,7-XII-2003
22 CabodeGatavillage,NW 30SWF673714 16-IX-l995,3-111-1996
23 CabodeGatavillage,NE 30SWF680715 7-VIII-2006
24 RamblaMoralesupstreamfromTorreMarcelo 30SWF675742 23-111-2002
25 TorreMarcelo 30SWF686743 11-111-1997,20-VI-2002
26 Pujaire 30SWF688718 20-V-2000
27 PlayadeLasSalinas 30SWF689696 12-X-1996
28 OrnithologicalObservatory,LasSalinas 30SWF695685 31-VIII-1997
29 ElBarranquetevillage 30SWF655768 14-XII-l997
30 RambladelHacho,ElBarranquete 30SWF722779 17-IV-1994
Collections. Studied material has that this taxon was distributed over a
beendepositedintheMuseoNacional wider área than previously reported,
deCienciasNaturales (MNCN)collec- including the Cabo de Gata-Níjar
tionandD.Morenocollection. NaturalPark(Figs.1-6).
Shellcharacters
RESULTS Inalllocalitiesinwhichthespecies
isfound(TableII),theshellofT. s. Iicli-
ThepopulationofT. subdentataheli- cella(Figs.2,3,7-30)isdepressed,with
cella living in El Alquián, Almería 4-5 whorls, and a sharp keel at the
(Spain),wasfoundinMarch1994.Sub- periphery.Theapertureisellipticalwith
sequentexplorationoftheáreashowed a slight angle corresponding to the
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MORENOANDRamos:Newdataon ThebasubdentatahelicellainAir
TablaI. Localidadesdemuestreoeneláreadeestudio,deoesteaeste, concoordenadas UTM,fechade
recolección, unabrevedescripcióndelsustratoylasespeciesvegetalesdominantes. Ibdaslaslocalidades
pertenecenalaprovinciadeAlmería. Laslocalidades7, 8, 10-23y25-28seencuentrandentrodel
ParqueNaturaldeCabodeGata-Níjar.
w- Substratum Vegetation
1 Sandanddunes Thymelaeahirsuta,Launaeasp.,Ammophilaorenaria
2 Sandanddunes Thymeloeahirsuta,Ammophilaarenaria
3 Sandanddunes Thymelaeahirsuta,Tamarixsp.
4 Sandanddunes Thymelaeahirsuta,Launaeasp.
5 Sandanddunes Agavesp.,Nicotianaglauca,Thymelaeahirsuto
6 Uncultivatedland Thymelaeahirsuta,Launaeasp.
7 Sandanddunes Thymelaeahirsuta,Ononisnatrix
8 Sandanddunes Thymelaeahirsuta,liziphuslotus
9 Rockyrambla Launaeasp.,Neriumoleanáer,Stipatenacissima
10 Sandanddunes Thymelaeahirsuta,liziphuslotus
11 Rockyramblaandsand Thymelaeahirsuta,Ammophilaarenaria,Juncussp.
12 Sandanddunes Ononisnatrix,Thymelaeahirsuta
13 Sandanddunes Ononisnatrix,Thymelaeahirsuta
14 Uncultivatedland Thymelaeahirsuta,Launaeasp.,Stipatenacissima
15 Uncultivatedland Thymelaeahirsuta,Launaeasp.,Stipatenacissima
16 Rambla Neriumoleanáer,Launaeasp.
17 Sandanddunes Ononisnatrix,Thymelaeahirsuta
18 Sandanddunes Thymelaeahirsuta,Launaeasp.,Agavesp.
19 Sandanddunes Imperatacylindrica,Limoniumsp.andSalsolasp.
20 Sandanddunes Ononisnatrix,Thymelaeahirsuta
21 Sandanddunes Androcymbiumeuropaeum,liziphuslotus
22 Sandanddunes Phoenixáactylifera,Ononisnatrix
23 Sandanddunes Tamarixsp.,Juncussp.
24 Rambla Tamarixsp.,Salsolasp.
25 Uncultivatedland Foeniculumvulgare
26 Uncultivatedland Thymelaeahirsuta,Launaeasp.,Eucalyptussp.
27 Sandanddunes Ononisnatrix,Thymelaeahirsuta
28 Sandanddunes Ononisnatrix,Thymelaeahirsuta
29 Uncultivatedland Androcymbiumeuropaeum,Thymelaeahirsuta,Launaeasp.
30 Rockyconglomerates Thymelaeahirsuta,Launaeasp.,Stipatenacissima
carina. The lip is thickened inside. shellrangesfrom 17to21 mminadult
Sometimes the last half oí the body specimens.
whorlclearlygrowsbelowthecarinaoí Thecolourofthespire,thekeeland
the anterior whorl (see also Fig. 37). theouterlip isusuallywhiteinapical
Shell surface is glossy and has a very view,whileatleastthelasthalfofthe
lightreticulatesculpture,whichisonly body whorl below the carina is palé
visiblewith a magnifyingglass, stere- browntodarkorange. Sometimes (less
omicroscope or SEM. The sculpture is than5%ofshells),thespirehasalight
formed by regular spiral streaks and browntoorangespiralband(thecentral
broader,butmoreirregular,radialribs part is occasionally dark) near the
(Fig. 37-38). The umbilicus is always carina.Whenthisbandispresent,there
closed. Themáximum diameter ofthe areusually2-6darkspiralbandsatthe
93
Iberus,25 (1),2007
Figure 1. Mapshowingthestudylocalities in theEasternáreaofAlmería Bayincludingthe
WesternpartoftheCabodeGata-NíjarNaturalPark,andestimatedabundanceofThebasubden-
tatahelicella: rareorscarce(1-10specimens),common (11-100specimens),verycommon (more
than100specimens)(seeTablesIorIIforlocalitynumbers).
Figura1.MapamostrandolaslocalidadesestudiadaseneláreaorientaldelabahíadeAlmería,inclu-
yendolaparteoccidentaldelParqueNaturaldeCabodeGata-Níjar,yestimadeabundanciadeTheba
subdentatahelicella:raraoescasa(1-10ejemplares),común(11-100ejemplares),muycomún(másde
100ejemplares)(verTablasIoIIparalosnúmerosdelocalidad).
mm
base below the carina. The interior of (Fig.40).Totalwidthisaround 1.6
theapertureispink. and the width of nucleus is approxi-
The protoconch is clearly distin- mately300microns.Thetransitiontothe
guished from the teleoconch by both teleoconchisfrequentlyveryabrupt.
colour and microsculture. The proto- Weonlyobservedvariationinshell
conchispurpletopinkishinlivespeci- shapeinthepopulationfromtheRambla
mensorfreshshells.Ithas1.7whorlsand de Amoladeras (localities 11 and 14),
is almost smooth (Fig. 39). Only very with a gradation from the usual
lightradialribscanbeobservedcióseto depressed, sharply keeled specimens
thesuturewiththeprotoconchnucleus (see above) to taller specimens witha
94
MORENOANDRAMOS:Newdataon ThebasubdentatahelicellainAlmería
TableII.PresenceofThebasubdentatahelicellaandotherlandsnailsin thestudyárea. Codesof
estimatedabundance:X(rare, 1-2specimens),XX(scarce,3-10specimens),XXX(common, 1l-
100specimens),XXXX(verycommon,morethan100specimens).
TablaII. PresenciadeThebasubdentatahelicellayotrosgasterópodosterrestreseneláreadeestudio.
Códigosestimadosdeabundancia:X(raro, 1-2ejemplares),XX(escaso,3-10ejemplares),XXX(común,
11-100ejemplares),XXXX(muycomún,másde100ejemplares).
j
'I
p p .§ =a =§ I e ^ 5 Sil ^1 ^ ~§ •§ ^
S-5-^áá^33^^<É^í§^=8
N9 Localities
1 TorredelPerdigal,ElAlquián XXX XX XX XX XXX XX X
2 PlayodeElAlquián,fishingboatsárea XXX XXX
3 DunesbetweenElAlquián-CasaEuerte XX XXX
4 CasaFuerte,ElAlquián X XX XXXX
5 CortijoelPino,ElToyo XXX XXX
6 UrbanizacióndeRetamar XXX XX XX XXX XX
7 RambladelAgua,Retamar X XXX XXX XXX
8 ForesttrailtoTorregarcía,westernárea XX XXX XXX XXX XX
9 CortijodelRetamar XXX XXX XX XX XX XXX XX XX XX x 10
1 ForesttrailtoTorregarcía,easternárea XX
11 RambladeAmoladeras,rightbank X X X XXX XXX
12PlayadeAmoladeras XXX
13BunkerofAmoladeras XXX
14OrnithologicalRefugeofAmoladeras X X X XX X XX X XX XXX X 10
andViewpoint
XX
15Amoladeras,Beacon X X XX X 6
16Amoladeras,1kmupstreamfrom X 1
OrnithologicalRefuge
17PlayadeElCharco XX 1
18AmoladerasInterpretationCenter XXX X 2
19RightbankofElCharcolagoon XXX XX XXX XX 4
20LeftbankofElCharcolagoon X XXX XXX XXX X XXX X 7
21 Mazarulleque XXX XX XXXX 3
22CabodeGatavillage,NW X XX XX XXXX 4
23CabodeGatavillage,NE XXX XXX 2
24RamblaMoralesupstreamfrom X X X XXX XX XX XX 7
TorreMarcelo
25TorreMarcelo XX XX XXXX XXX 4
26 Pujaire X XX XXX XXX XXX 5
27 PlayadeLasSalinas XXX X XXXX 3
28OrnithologicalObservatory,LasSalinas XXX XXX 2
29ElBarranquetevillage XX XX XXX XXX 4
30RambladelHacho,ElBarranquete X XX 2
Numberoflocalities: 6 2 4 13 2 5 3 10 2 2 16 6 20 18 1 4
95
Iberus,25 (1),2007
Figures2-6. Thebasubdentatahelicella.2,3:livinganimáisfromCasaFuerte,ElAlquián,Almería;4,
5:typicalhabitatandmáximumabundanceonbushesofThymelaeahirsuta;6:syntopicpopulation
ofThebasubdentatahelicellaandThebasp.onFoeniculumvulgare,atRambladeAmoladeras,Almería.
Figuras2-6.Thebasubdentatahelicella.2,3:animalesvivosenCasaFuerte,ElAlquián,Almería;4,
5:habitattípicoymáximaabundanciasobreelarbustoThymelaeahirsuta;6:Thebasubdentata
helicellaandThebasp.,juntossobreFoeniculumvulgare,enlaRambladeAmoladeras,Almería.
96
MorenoandRamos:Newdataon Thebasubdentata inAlmería
Figures7-36.ShellsofThebaspp.fromElAlquiánandCabodeGata,Almería.7-18: Thebasub-
dentatahelicellafromCasaFuerte,ElAlquián; 19-30: Ts.helicellafromrightbankofRamblade
Amoladeras;31-33: Thebasp.fromrightbankofRambladeAmoladeras;34-36: Thebapisaría
pisaríafromTorreMarcelo.
Figuras7-36. ConchasdeThebaspp.fromElAlquiányCabodeGata,Almería. 7-18:Thebasub-
dentatahelicelladeCasaFuerte,ElAlquián;19-30:T.s.helicelladelaRambladeAmoladeras;31-
33:Thebasp.delaRambladeAmoladeras;34-36:ThebapisanapisanadeTorreMarcelo.
97
Iberus,25 (1),2007
very slight keel, nearly absent, only distalpart.Thediverticulumiswideand
visibleonthelasthalfofthebodywhorl enlarges distally; it is longer than the
near the aperture. The colourofthese distalpartoftheductand thusreaches
specimensisalsovariable, fromwhite beyond thebursa copulatrix, which is
specimens(withorangebase)tospeci- rounded toapyriformshape.Thefree
menswithtwodarkspiralbandsabove oviductisthinandvisiblyshorterthan
thekeel,darkspirallyarrangedblotches thevagina,whichistwo-thirdstoalmost
nateatrhtehebsauste.ureThanedb3a-s8adlarbkanspdisralcbaanndbse stmwailcle,it3smlenmgthi.nTlehnegdtahrtonsaacviesrraeglea.tiTvehley
simple(Fig.24,27)or,morerarely,com- uterusandprostateformacharacteristic
posed of blotches, or united forming loopciósetothealbumengland,which
onlytwobroadspiralbands(Fig.30). islong,slender,andtongue-shaped.The
vesicula seminalis is very darkly pig-
Softpartscharacters mented and measures from 1.4 to 1.9
The animal of T. s. helicella is long mm.Thehermaphroditeductendsnear
andnarrow(Figs.2-3),lightgrey,darker itsdistalpart(Figs.45,50-51).
on the mantle and on the área of the Initsrestingposition(asthegenital
headbetweenthetentacles.Allfourten- system is situated inside the animal)
tacles have a retractor muscle that is (Fig.49),theproximalpartoftheflagel-
pigmentedinadarkgreycolour,almost lummakesacharacteristiclooparound
black, more evident inthe upperpair the penis retractor muscle. The fold
thancanbeobservedthroughthetrans- madeby the diverticulum around the
parentbodywall. Thereareno differ- proximalpartoftheuterusisalsoquite
ences in body pigmentation between characteristic.Figure50showsthisfold
individuáishavingdifferentcolourpat- as well as the diameter differences
ternsintheshells(dorsalpartwhiteor betweentheproximalpartofthebursa
withbands). copulatrixductandthediverticulum.
Genitalsystemcharacters Habitatandecology
FivespecimensfromRamblaAmo- Theba s. helicella lives in a narrow
laderasweredissectedandthedifferent strip ofland,about2-3kmwide,near
organsofthegenitalsystemweremea- thesea.Thecoastaláreaischaracterized
sured(Fig.45-52,TableIV).Thepenisis bysandbeaches,dunesand"ramblas"
moreorlessspindleshaped;proximally (seasonalwatercourses)wherethevege-
itisenlargedtodifferentdegrees(Figs. tationhasAfricanelements(asZiziphus
45-46), while distally it becomes dis- lotus).Theclimateissemiaridwithvery
tinctlyslender,asthinastheepiphallus. scantyrainfall.
The inside of the penis shows strong This species is very common on
radialpleats (Fig. 47, 52) and apenial Thymelaeahirsuta,Ziziphuslotus,Launaea
papilla at its thinner distal part. The sp.andotherbushes.Itisalsoobserved
penisretractormuscleattheinsertion ongrasses,asAmmophilaarenaria,Imper-
pointofthepenisthickensslightly.The ata cylindrica and Stipa tenacissima,
length of the penis retractor muscle rushes, as Juncus sp., small trees, as
variesgreatly(fromeightmmtomore Tamarixsp. andNicotianaglauca (inva-
thantwicethislength).Theflagellumis sivespecies)oronintroducedspeciesas
thin and longer than the penis and Agavesp.
epiphallus combined (frequently over InRambladeAmoladeras,T.s.heli-
twiceaslong). Theflagellumis some- cella is common, with shells and live
whatlongerthantherelativelythickand specimensonsandandAmmophilaare-
longpairofmucousglands.Thedistal naria,Juncussp.,Thymelaeahirsuta,Zizi-
endwasbifidinonespecimen(Fig.48). phus lotus and otherbushes. Thereare
Theproximalpartofthebursacopula- somespecimensofT. s.helicellawithout
trix duct has an enlarged base and is keelthatareonlyfoundnearrockout-
clearly shorter than its relatively thin cropswhichareoriginatedbytectonic
98