Morphological and biometrical researches on Austrian Clausiliids. Shell morphology and variability in Clausilia dubia Draparnaud, 1805

27 Pages·1997·10.5 MB·English

by  Karl Edlinger

©
SociedadEspañoladeMalacología Iberus, 15 (2): 95-121,
Morphological and biometrical researches on Austrian
Clausiliids. Shell morphology and variability in Clausilia
dubia Draparnaud, 1805
Investigaciones biométricas ymorfológicas en Clausílidos deAustria.
Morfología y variabilidad de la concha de Clausilia dubia Drapar-
naud, 1805
Karl EDLINGER*
Recibidoel8-1-1996.Aceptadoel28-V-1997
ABSTRACT
Morphological and biometrical studies on shells of some Austrian populations of Clausilia
dubia Draparnaud, 1805, show a greatvariability in size and in the other morphological
features within the species as a whole and also within single populations. Investigations of
the variability of characters by metrical and statistical methods in some populations dis-
close impressive metrical divergences and morphological differences.
These results give rise to the question whether the characterization of Clausilia dubia as a
polytypic species, as suggested by Klemm (1960, 1973), is ¡ustified.
RESUMEN
Estudios morfológicos y biométricos en conchas de algunas poblaciones austríacas de
Clausilia dubia Draparnaud, 1805, muestran una gran variabilidad en el tamaño y en
otros caracteres morfológicos tanto en el conjunto de la especie como en poblaciones ais-
ladas. Investigaciones sobre la variabilidad de caracteres por medio de métodos métricos
y estadísticos de algunas poblaciones mestran importantes divergencias tanto métricas
como morfológicas.
Estos resultados originan la pregunta de si está justificada la caracterización de Clausilia
dubiacomo una especie politípica, como sugiere Klemm (1960, 1973).
KEYWORDS: Clausiliadubia,subspecies, measures,distribution, morphologicalcontinuum.
PALABRASCLAVE: Clausiliadubia,subespecies,medidas,distribución,continuidadmorfológica.
INTRODUCTION
As in great parts of Europe also in monspeciesthatisbelievedtobepolyty-
Austria, specially in the eastern parts of pie (Klemm, 1960, 1973; Fechter and
theAlps and in the adjacent áreas, Clau- Falkner, 1990;Kearney, Cameronand
silia dubia Draparnaud 1805 is a widely Jungbluth, 1983; Nordsieck, 1990).
diffused and in some localities a com- Klemm (1960, 1973) gave a survey ofdi-
*NaturhistorischesMuseumWien, 3. ZoologischeAbteilung, Burgring7,A-1014Wien,Austria.
95
Iberus, 15 (2), 1997
C.d.dubia C,d.speciosa C.d.huettneri C.d.schlechti C,d.graciliorC.d.tettelbachiana C.d.floningiana C.d.bucculenta C.d.runensis C.d.kaeufeli
Figure 1. Distribution and vertical succession of Clausilia dubia subspecies as is suggested by
KLEMM (1960).
Figura 1. Distribuciónysucesión verticalde las subespecies deClausilia dubia, taly como sugiere
Klemm
(1960).
verse "subspecies" of Clausilia dubia ac- 1973). Furthermore, Klemm (1960) sug-
cording to the characters suggested by gested a vertical pattern of distribution
severalauthors. and an altitude dependent succession of
Traditionalclassificationwasbasedon diversesubspeciesattheeasternrangesof
a subjective selectionofcharactersbelie- theAlps(Fig.1).Hetriedtoexplaintheob-
ved to be important. This classification served distribution pattern by probable
dependedonthepreferencesofthesingle re-immigration events in the alpine re-
authors. In some cases, subspecies are giónafterthePleistoceneandadaptation,
evendescribedaccordingtothepresence enforcingtheroleoftheenvironment(al-
oftypicalfeaturesintheshelloffeworsin- titude).
gle specimens. Holoyak and Seddon Examinationand possible revisiónof
(1988) and Nordsieck (1990) examined theseinterpretationshavetocriticallycon-
someofthesedescriptionsandofferedre- siderthedefinitionandthemeaningofthe
asonablerevisions. term subspecies as it is used under va-
SomeoftheseClausiliadubia"subspe- riousperspectivesbyseveralauthors.For
cies" are considered to be widely distri- thepractical requirementofthe collector
buted,otherstobelocalizedinsmalláreas and forthetaxonomicorderingofcollec-
or subdivided into isolated populations tionsthetechnicalterm"subspecies"asba-
thatliveinseparated sites(Klemm, 1960, sed on peculiar morphological features
96
EDLINGER: Shell morphologyand variability in Clausilia dubiaDraparnaud, 1805
Rax Schneeberg
HoheWand
Wienerwald
Figure2.Aprofiloftheestern edgeoftheAlps and theWienerwaldwith thesamplelocalities.
Figura2. PerfildelacaraestedelosAlpesydelWienerwaldcon laslocalidadesdemuestreo.
may certainly be useful. However, it is asubjectiveandracherarbitraryapproach.
scientificallymoreimportanttoconsider Itisthereforenecessarytostudyasgreat
the conceptualbackground ofthe termi- a number as possible of morphological
nology.Inthegivencontexttheconceptof charactersandtotakemeasurementsofthe
raceorsubspeciesreferstobiologicalunits greatestpossible exactness to establish a
that are groups of related populations solidbasisforstatisticalevaluations(Ne-
which are genetically characterized and, meschkalandkothbauer, 1988;koth-
inthecaseofverylongisolation,maybe bauer, nemeschkal, sattmann and
theforerunnersof"validspecies"(Mayr, Wawra, 1991; Nemeschkal, 1990, 1991,
1967: 387;SudhausandRehfeld, 1992). 1993; Mylonas, Krimbas, Tsiakas and
This view is highly important for tradi- Ayountanti, 1990).
cionalevolutionarybiology especiallyin Such investigations may clear up,
the frame ofDarwinian models for evo- whether the populations studied by
lutionarychange. Klemmmeetallrequirementsofareliable
Inrespecttothebiologicalrelevanceof identification as subspecies (Edlinger
thesubspeciesconcept,SudhausandReh- andFischer,1997).Itisalsoworthwhile
feld (1992) are suggesting that "geo- toattemptacriticalrevisiónofsomesam-
graphicraces" (subspecies)areallopatric plesoftheMuseumofNaturalHistoryin
populations of a species, which can be Vienna (NHMW). This paper is first at-
distinguished taxonomically. The diag- tempt at elaborating a new basis for the
nostic characters ofraces should be pre- discussionofthe Clausilia dubia problem
sentin90ormorepercentofindividuáis bymorphologicalmeasurements.Infuture
ofthepopulación. " the anatomyofthesoftpartsandgeneti-
Osche (1994) claims that 75 percent calanalysesmightbealsoconsidered.
ormoremembersofapopulaciónmustbe
morphologicallydistinguishablefromthe
membersofanotherpopulación.Popula- MATERIALANDMETHODS
tionsonlyinthiscaseshouldbeaccepted
asvalidsubspecies.InthispaperOsche's 606 specimens ofClausilia dubia from
definiciónisassumedasaverytolerantand differentlotscollectedinvariousáreasof
usefulconcept. the "Wienerwald" (LowerAustria inthe
Accordingtothepresuppositionsjust southwest of Vienna) the massif of the
given, studiesreferringtothesubspecies "HoheWand",the"Schneeberg" andthe
problemhavetotreatlargenumbersofin- "Rax" were investigated. The localities
dividuáis and to apply methods ofgrea- from which the samples carne were si-
terexactness thantheusual descriptions tuatedataltitudesbetween270and 1850
m
anddiscriminationsofcharactersbasedon (Fig.2).
97
Iberus, 15 (2), 1997
MH(inmm/10)
GW(l-5)/ MB(inmm/10)
BR(1-6) LFí1 5>
Figure3. Measurestakenfromtheshells: shell-height(H), shell-width (B),height (MH) andwidth
(MB)oftheaperture,distanceofribs (RA),numberofwhorls(WZ),anglebetweenthespindleaxis
and the upperpalatal (leftside) (A).
Figura3. Medidastomadasenlasconchas:altura (H), anchura (B), altura (MH)yanchura(MB)dela
apertura, distancia de las estrías (RA), número de vueltas (WZ), ángulo entre elejedelhusoypalatal
superior(lado izquierdo) (A).
Samples(NumberofSample(Sample m/34spec),H8(Plateau1020m/4spec);
W
localities,altirude/ numbersofspecimens. =Wienerwald:Wl(Anninger,400m/11
R = Rax: R4 (Reichenau, 700 m/1 spec), spec),W2(Anninger,450m/4spec),W3
R5 (Aufstieg z. Knappenhof, 730 m/5 (Módling-Klause,260m/8spec),W4(Hu-
spec),R7(Knappenhof, 800m/24spec), sarentempel, 480 m/14 spec), W5 (Auf-
RIO(Thórlweg,850m/5spec),Rll(Thórl- gangAnninger,270m/11spec),W6(Peils-
weg,960m/1spec),R12(Thórlweg,1120 tein,400m/8spec),
m/29 spec), R13 (Thórlweg, 1260 m/20 Several individuáis were dissected.
spec), R14 (Thórlweg, 1320 m/12 spec), Dissectionsdidnotrevealsignificantdif-
R15 (Jakobskogel, 1685 m/8 spec); S = ferences in the genital apparatus. 18
Schneéberg:SI(Puchberg,560m/15spec), shells, syntypes of Austrian and South
S2 (Schneebergbahn, 750m/57spec),S3 Tyrolean (Italy) localities, given in loan
(Schneebergbahn,790m/5spec),S4(Sch- by the Natur-Museum Senckenberg as
neebergbahn, 945 m/30 spec), S5 (Sch- typicalrepresentativesofvarioussubspe-
neebergbahn,1165m/9spec),S6(Schne- cieswereusedforcomparisons(Fig. 1).
ebergbahn, 1370m/6spec),S8(Waxriegl They are:
11, 1820 m/4 spec), S9 (Waxriegl 11, 1850 1. Clausüia dubia dubia Draparnaud,
m/26 spec), S10 (Schneebergbahn, 1650 1805 (SMF 163024a)
m/11spec),H=HoheWand:Hl(Dreistet- 2. Clausüia dubia speciosa A. Schmidt,
ten, 530 m/60 spec), H2 (Einhornhóhle, 1857(SMF 163025a)
600m/12spec),H3(Drobilsteig,700m/24 3. Clausüia dubia speciosa A. Schmidt,
spec),H4(Drobilsteig,760m/69spec),H5 1857(SMF 163026a)
(Auffahrtz. Plateau,830m/74spec),H6 4. Clausüia dubia obsoleta A. Schmidt,
(Plateau1020m/6spec),H7(Plateau1020 1857(SMF 163027a)
98
EDLINGER: Shell morphology and variability in Clausilia dubia Draparnaud, 1805
Figure4. Shellforms (7stagesfromclub-shaped-left- tospindle-shaped-right-).
Figura4. Formasdelaconcha(sieteestadiosdesdeformademaza-izquierda-hastaahusada-derecha-).
5. Clausilia dubia huettneri Klemm, from pear-shaped to deltoid form, the
1960 (SMF 1630248) angle between the spindle axis and the
6. Clausilia dubiaschlechtiA. Schmidt, edge of the upper palatal (0.5 degree
1857(SMF 163030a) exactness), the mean of 5 rib distances
7. Clausilia dubia gracilior Clessin, (RA, Fig. 3) on the last whorl, and the
1887(SMF 163031a) number ofwhorls per shell (WZ, exact-
8. Clausilia dubia tettelbachiana Ross- ness: 0.25) were recorded. By compari-
mássler, 1838 (SMF 163032a) sonwith stencils themorphological cha-
9.ClausiliadubiaotvinensisH.Gallens- racters of the form of the shells (GH, a
tein, 1895 (SMF 163033a) series of 7 stages from club-shaped, to
10. Clausilia dubia grimmeri L. extremely spindle-shaped specimens,
Pfeiffer, 1848 (SMF 163034a) Fig4),thedepth,andthethicknessofthe
11. Clausilia dubiafloningiana Tscha- basalgroove (BR, 6stages, Fig. 5), thela-
pek, 1886 (SMF 163035a) teral internalbulge (GW, ontheleft side
12. Clausilia dubiafloningiana/gracilior oftheaperture,5stagesofthickness(Fig.
(SMF 163036) 5), and the incisión in the columellar la-
13. Clausilia dubia bucculenta Klemm, mella(LF,5stages,Fig.5)wererecorded.
1960 (Holotypus, SMF 163037) The measured valúes of the follo-
14. Clausilia dubia runensis Tschapek, wingfeatureswereprocessedbyaWIN-
1883 (SMF 163039a) DOWS-EXCEL 5.0 and a WINDOWS
15.ClausiliadubiamoldanubicaKlemm, SPSS6.0program(BrosiusandBrosius,
1960(Holotypus, SMF 163040) 1995):
16. Clausilia dubia kaeufeli Klemm, - Mean of shell heights in each spot
1960(Holotypus, SMF 163042) check
17. Clausilia dubia alpicola Clessin, - Standard deviation of shell heights
1878 (SMF31969) ineachspotcheck
18. Clausilia dubia reticulata Pini, 1883 - Mean of shell heights in each spot
(SMF31936) check
Theshellsweremeasuredunderabi- - Standard deviation shell heights in
nocular microscope; the measurements eachspotcheck
were repeated three times. Inthe case of - Correlation (Pearson's) Coefficient
different results a special check was ofall11 valúes:
made. The height (H, Fig. 3) and the
width (B, Fig. 3) ofthe shell as a whole,
the height (MH, Fig. 3) and the width
(MB, Fig. 3) of the aperture, the form of
the aperture (MF, a series of 9 stages (N-l)-Sx-Sy
99
Iberus, 15 (2), 1997
Figure 5. Basal groove (6 stages, upper row); lateral bulge (5 stages, middle row); incisión in the
columellarlamella (5 stages, lowerrow).
Figura5. Surcobasal(6estadios, arriba);protuberancialateral(5estadios, centro);incisiónenlalame-
lacolumelar(5estadios, abajo).
(R= Pearson's Coefficient; N= from dissimilarities computed on the
number of cases; X, Y= variables; Sx, basis of the sums of squared valúes of
Sy= standard deviation of the varia- distances of each character. Thereby the
bles). spectrum of similarities and differences
between all individuáis of a spot check
By means of the WINDOWS SPSS could be elaborated. The dendrograms
6.0 programs a factor extraction and a contain specimens of various clusters
principie component analysis were exe- according to their graduated similarity
cuted. "Community" delivers informa- (BrosiusandBrosius, 1995).
tion about the quota of spreading of Theformulaofthegeneraldistances:
one valué that canbe traced back to all
other valúes. "Eigenvalue" is a valué of D2= Í(Xí-Yí)2
the regression factors. It represents the i=l
quota of spreading of all valúes as (D= distance; t)= number of varia-
interpreted by special regression bles;X, Y=cases)
factors. Areductionprocess restricts the
numbers of factors in the final statistics
to that exceeding 1.0. The factor matrix RESULTS
shows the influence of the regression
factors on every variable as a percen- Means of shell height and shell
tage of 1. width: The means of the shell height
The measured variables of the and shell width differ in all sampling
samples in conjunction with the valúes áreas. Thelowestvaluéwas found atthe
of the specimens described by Klemm "Hohe Wand" región, the highest in the
(1960) and the valúes of specimens of "Wienerwald" área. Comparisons of the
Clausilia dubia alpicola and C. d. reticulata means at different altitudes reveal that
wereutilized forcomputinghierarchical Klemm's (1960) suggestion of a succes-
clusters as dendrograms. Forpurpose of sion ofdifferent shell heights (according
cluster analysis the measured valúes to a succession of "races" resp. subspe-
were transformed to "z-values", valúes cies, high valúes at low altitudes, low
with a mean of and a standard devia- valúes at high altitudes) is not generally
tion of 1. Hierarchical clusters result convincing (Fig. 7).
100
EDLINGER: Shell morphology and variability in Clausilia dubiaDraparnaud, 1805
NHMW
Figure6.Twospot-checksofthecollectionofthe (NaturhistorischesMuseum,Wien). In
theupperrow"Clausiliadubiaschlechti",Inv.Nr. 11.229NHMW.Thespecimenintheupperrow
attheleftbelongstoNeostyriacacorynoides(Held, 1836). Intherowbelow C. d. "schlechtf, Inv. Nr.
62. 348 NHMW. Thesespot-checksshowusahighvariabilityinthe "subspecies". Scalebar 1 cm.
NHMW
Figura6. Dosmuestrasdelacoleccióndel (NaturhistorischesMuseum, Wien). Enlafilasupe-
rior 'Clausiliadubiaschlechti", Inv. Nr. 11. 229NHMW.Elespécimendelaizquierdadelafilasupe-
riorperteneceaNiostyriacacorynoides (Held, 1836). EnlafilainferiorC. d. "schlechti",Inv.Nr. 62.
348NHMW.lasfotografíasmuetran unaalta variabilidaden lassubespecies. Escala 1 cm.
Correlation coefficients: A very tude and the shell height (Táble I) but a
remarkable outcome of the study was a high correlation between altitude and
lowpositivecorrelationbetweenthealti- theincicioninthecolumellarlamella.
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Iberus, 15 (2), 1997
2000
1000
SYMB
DH
2000
SYMB
Figure 7. Scatterplots ofthe means ofthe heightandwidth ofthevarious samples and the altitu-
deofsamplingpoints.
Figura 7. Diagramadepuntosdelasalturasyanchurasmediasdelasdistintas muestrasylaaltitudde
lospuntosdemuestreo.
Inallfourregionsasignificantcorre- height and width of the aperture, and
lation between the altitude and the betweenwidth ofthe shell and width of
height of the shells could not be confir- the aperture, are more or less remarka-
med. A máximum of correlation was ble. Correlation between altitude and
found between shell height and the most of the shell variables with the ex-
height of the aperture. Correlations bet- ception of the columellar lamella (nega-
ween shell height and heigth of the tivecorrelation: -0.5123)islow (TableI).
aperture, shell height and number of
whorls, shell form and number of Primary factor analysis: For the
whorls, shell formand shellheight, shell primary factor analysis all valúes were
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EDLINGER: Shell morphologyand variability in Clausiliadubia Draparnaud, 180!)
TableI. Correlationcoefficients (bivariate) ofaltitude (ALT), breadth (B), basalgroove (BR), shell-
form (GHF), internalbulge (GW), heighth (H), theincisióninthecolumellarlamella (UL),width
ofaperture (MB), angle between the upper palatal and the spindleaxis (A), height ofthe aperture
(MH), distanceofribs (R) andnumberofwhorls (WZ).
TablaI. Coeficientesdecorrelación (bivariables)dealtitud(ALT), anchura (B),surcobasal(BR),forma
de la concha (GHF),protuberancia interna (GW), altura (H), incisión en la lámela columelar (UL),
anchuradelaapertura (MB), ánguloentreelpalatalsuperioryelejedelhuso (A), alturadelaapertu-
ra (MH), distanciaentrelasestrías (R)ynúmerodevueltas (WZ).
A ALT B BR GHF GW
A .0000 -.0487 .1696** .0493 .2272** .0646
1
ALT .0487 1.0000 ,0032 .1262** ,0036 .2082**
B .1696** ,0032 1.0000 .1297** .2510** .0438
BR .0493 .1262** .1297** 1.0000 .0148 .3307**
GHF .2272** -.0036 .2510** .0148 1.0000 .1171**
GW .0646 .2082** .0438 .3307** .1171** .0000
1
H .2011** ,0021 .3814** .1351** .5258** .1397**
LF .0213 .5123** .1453** .2311** ,0741 -.0542
MB .0822* .1590** .4693** .1606** .0446 .1331**
MH .0450 .0214 .5417** .1644** .0656 .1621**
R .1370** .1850** .0931* -.0704 .2172** .1103**
WZ .2812** .1711** .0127 .0745 .5760** .0632
H LF MB MH R WZ
A .2011** .0213 .0822* .0450 .1370** .2812**
ALT .0021 .5123** .1590** .0214 .1850** .1711**
B .3814** .1453** .4693** .5417** .0931* .0127
BR .1351** .2311** .1606** .1644** -.0704 .0745
GHF .5258** ,0741 .0446 .0656 .2172** .5760**
GW .1397** -.0542 .1331** .1621** .1103** .0632
H .0000 .0780 .4968** .7071** .1411** .6663**
1
LF .0780 1.0000 .2288** .0913* .1501** .0891*
MB .4968** .2288** .0000 .5965** ,0230 .1733**
1
MH .7071** .0913* .5965** .0000 ,0412 .2455**
1
R .1411** .1501** ,0230 ,0412 1.0000 .2058**
WZ .6663** .0891* .1733** .2455** .2058** .0000
1
*= Signif. LE .05;**= Signif. LE .01 (2-tailed)
used irrespective of the altitude. The Factor1hasasignificantinfluenceon
analyses result four factors with an thewidthoftheshell,theshellheight,the
Eigenvalue ofmore than 1.0. One analy- width ofthe aperture, theheight ofthe
sis was done including the NMS speci- apertureandthenumberofwhorls.
mens (Table II), the other only with the Factor2hasasignificantinfluenceon
own samples (Table III). The results of the angle between the axis and the left
both analyses were corresponding at a palatal, thewidthoftheaperture, therib
highdegree. distanceandthenumberofwhorls,factor
03
Iberus, 15 (2), 1997
Table II. Primary component analysis factors of all samples including the NMS specimens.
Abbreviationsas inTable I.
TablaII. Factoresdelanálisisdecomponentesprincipalesdetodaslas musirásincluyendo losejemplares
NMS. Abreviaturascomoen la TablaI.
Initial Statistics
Variable Communality Factor Eigenvalue PctofVar Cum Pct
A .00000 3.14275 31.4 31.4
1 1
B 1.00000 2 1.48937 14.9 46.3
BR 1.00000 3 1.34787 13.5 59.8
GW
1.00000 4 1.09305 10.9 70.7
H 1.00000 5 .81589 8.2 78.9
LF 1.00000 6 .69772 7.0 85.9
MB 1.00000 7 .54068 5.4 91.3
MH 1.00000 8 .42572 4.3 95.5
R 1.00000 9 .32418 3.2 98.8
WZ 1.00000 10 .12276 1.2 100.0
PC extracted 4 factors
FactorMatrix
Factor 1 Factor 2 Factor 3 Factor4
A .24107 -.39349 .57325 ,01561
B .64730 .28942 -.49248 ,01712
BR .19488 .59543 .52902 .22231
GW
.11069 .50354 .53469 ,34493
H .89714 .19205 .07467 ,16390
LF .25618 .22266 .08430 .85909
MB .75790 .21202 -.17180 .03663
MH .85718 10931 ,19219 ,16564
.
R .24758 .55811 .01044 .35599
WZ .61193 -.43340 .36292 ,06089
Final Statistics
Variable Communality Factor Eigenvalue PctofVar Cum Pct
A .54182 3.14275 31.4 31.4
1
B .74559 2 1.48937 14.9 46.3
BR .72179 3 1.34787 13.5 59.8
GW
.67067 4 .09305 10.9 70.7
1
H .87418
LF .86036
MB .65022
MM
.81108
R .49962
WZ
.69772
Skipping rotation 1for extraction 1 ¡n analysis 1
104