SCIENTIA MARINA 70 (2)
June 2006, 227-234, Ba celona (Spain)
ISSN: 0214-8358
Obse a ions on he on ogene ic and in aspeci ic
changes in he adula o Polyce a au an ioma gina a
Ga cía and Bobo, 1984 (Gas opoda: Opis ob anchia)
om Sou he n Spain
INES MARTÍNEZ-PITA, JOSE M. GUERRA-GARCÍA, ANA I. SÁNCHEZ-ESPAÑA
and FRANCISCO J. GARCÍA
Labo a o io de Biología Ma ina, Depa amen o de Fisiología y Zoología, Facul ad de Biología, Uni e sidad de Se illa,
A da. Reina Me cedes 6, 41012 Se illa, Spain. E-mail: [email p o ec ed]
SUMMARY: Polyce a au an ioma gina a Ga cía and Bobo 1984 has a s able popula ion in he in e idal a ea o El Po il beach
(Huel a, SW Spain). This ac allowed specimens o di e en sizes o be collec ed om Ma ch 2001 o Decembe 2003. In his
pape , he on ogene ic a ia ions o he adula o P. au an ioma gina a a e s udied. The adulae o 141 specimens we e exam-
ined, 138 om El Po il and 3 om La He adu a (G anada, SE Spain). Specimens o 1.5-2 mm in leng h lack he ypical adu-
la desc ibed o P. au an ioma gina a. They ha e he so called p e- adula whose ee h a e di e en in size and shape om he
ypical adula o he adul s. In he specimens o 3 and 4 mm he p e- adula coexis s wi h he cha ac e is ic adula, which is he
single s uc u e p esen in he specimens la ge han 4 mm. The ollowing ea u es o he adula a e included in his s udy: adu-
la leng h, numbe o ee h ows and leng h o he ou e la e al ee h. Acco ding o he h ee measu ed a iables, he a ini ies
among specimens wi hou a p e- adula we e es ablished h ough clus e analysis, which de ined h ee di e en g oups (4-10 mm,
11-22 mm and 23-48 mm). Co ela ions be ween specimen leng h and adula leng h, numbe o ows and mean leng h o ou e
la e al ee h we e signi ican . Feeding s a egies could be ela ed o he di e en mo phology o he adula es ablished by he
Clus e analysis.
Keywo ds:Polyce a au an ioma gina a, Opis hob anchia, Gas opoda, adula, on ogene ic a ia ion.
RESUMEN: CAMBIOS ONTOGENÉTICOS E INTRAESPECÍFICOS OBSERVADOS EN LA RÁDULA DE POLYCERA AURANTIOMARGINATA GARCÍA
AND BOBO, 1984 (GASTROPODA OPISTHOBRANCHIA). – Polyce a au an ioma gina a Ga cía y Bobo, 1984 mues a una población
es able y en la localidad de El Po il (Huel a, SW de España), lo que ha pe mi ido la ecolección, desde ma zo de 2001 has a
diciemb e de 2003, de un al o núme o de ejempla es de odos los amaños. En el p esen e es udio se ha ex aído la ádula de 141
animales, 138 ecogidos en la zona in e ma eal de El Po il y 3 en La He adu a (G anada). Los amaños de los animales han osci-
lado en e 1.5 mm y 48 mm. Se ha podido obse a en los indi iduos de en e 1.5 y 2 mm la exis encia de una p e- ádula cuyos
dien es son mo ológicamen e di e en es a los de la ádula de los indi iduos mayo es; sin emba go, en los ejempla es de 3 y 4
mm es a p e- ádula coexis e con la ádula ípica, siendo es a es uc u a la única p esen e en indi iduos de longi ud igual o mayo
a 4 mm. A cada una de las ádulas ex aídas, an o con p e- ádula o sin ella, se le ha medido la longi ud o al de la cin a, la lon-
gi ud del dien e la e al ex e no y el núme o de ilas de dien es. Conside ando los es pa áme os medidos, las a inidades en e los
ejempla es sin p e- ádula se es ablecie on a pa i de análisis de Clus e , que de inie on es g upos dis in os (4-10 mm, 11-22 mm
y 23-48 mm). Las co elaciones exis en es en e la longi ud de los indi iduos y la longi ud de la ádula, el núme o de ilas y la
longi ud media de los dien es ue on signi ica i as. Las di e encias mo ológicas econocidas en los g upos conside ados pod í-
an es a elacionadas con dis in as es a egias alimen a ias.
Palab as cla e:Polyce a au an ioma gina a, Opis hob anchia, Gas opoda, ádula, a iación on ogené ica.
sm70n2227-2025 25/5/06 16:02 Página 227
INTRODUCTION
The mo phology o he adula ee h, including
aspec s such as he numbe o ee h ows and ee h
pe hal - ow, has o en been used o di e en ia e
species o opis hob anchs. Ne e heless, he
in aspeci ic and on ogene ic adula a ia ions in
he opis hob anchs ha e been p o ed in some
species. Bleakney (1989) e ealed a mo phological
a ia ion o he adula o Placida dend i ica (Alde
and Hancock, 1843), compa ing popula ions om
he Paci ic and A lan ic. Be sch (1976, 1978a,
1978b) s udied he adulae o Discodo is e elinae
Ma cus, 1955 and se e al gene a o Ch omo-
do ididae, concluding ha he e is a mo phological
a ia ion be ween he newly o med ee h, si ua ed
in he newe ows, and he o he ee h, si ua ed in
olde ows. Fu he mo e, he numbe o ee h ows
inc eases wi h he leng h o he animal.
P u o -Fol (1926) desc ibed he p esence o a
“p e- adula” o dis inguish he i s ee h ows om
he emaining ows, du ing he ju enile s age o he
police id nudib anch Polyce a quad ilinea a
(Mülle , 1776). Focusing on he amily
Polyce a idae, Fe ei a (1977) epo ed di e en
adula pa e ns be ween ju enile and adul s in
species o he genus T iopha Be gh, 1880. Recen ly,
Ocaña e al. (2004) p o ided da a on he on ogene -
ic a ia ion in numbe and mo phology o adula
ee h in se e al species o genus Tambja Bu n, 1962,
compa ing ju enile and adul s ages.
This pape examines in aspeci ic adula a ia-
ions o Polyce a au an ioma gina a Ga cía and
Bobo, 1984 om sou he n Spain, and p o ides da a
on he a ia ion in numbe and mo phology o ee h
ows in specimens a di e en s ages, be ween 1.5
and 48 mm in leng h.
MATERIAL AND METHODS
The p esen s udy was conduc ed using speci-
mens om El Po il beach (Huel a, SW Spain)
(37º12´40´´N, 7º7´50´´W) and La He adu a
(G anada, SE Spain) (36º44´N, 3º43´W) (Fig. 1).
Th ee animals we e collec ed in La He adu a and
138 o hem in El Po il om Ma ch 2001 o
Decembe 2003. The specimens we e ca ied ali e o
he labo a o y, whe e hey we e measu ed and ixed
in 4% o malin. The adulae o all he specimens
we e s udied by using op ic mic oscopy and hose o
he ju eniles we e also pho og aphed using SEM.
The leng h o he adula, he numbe o ows and he
leng h o he ou e la e al oo h we e measu ed wi h
a mic ome e ocula . To de e mine he size o he
adula ee h we conside ed he leng h o he ou e
la e al oo h, om he apical cusp o he base (Fig. 2).
The a ini ies among specimens acco ding o he
h ee measu ed a iables ( adula leng h, numbe o
ows and he mean alues o oo h leng h) we e es ab-
lished h ough Clus e analysis using he UPGMA
me hod (Unweigh ed Pai G oup Me hod using
A i hme ic a e ages) (Snea h and Sokal, 1973), based
on Euclidean dis ance. Fo hese analyses he ou
specimens wi h a p e- adula we e no included. Once
he g oups o specimens we e es ablished h ough he
Clus e analysis, he possible di e ences o he h ee
SCI. MAR., 70(2), June 2006, 227-234. ISSN: 0214-8358
228 • I. MARTÍNEZ-PITA e al.
IBERIAN
PENINSULA
EL PORTIL
LA HERRADURA
FIG. 1. – Map o Spain showing he sampling loca ions.
FIG. 2. – Ou e la e al oo h. The ba shows he measu ed leng h o
de e mine he size o he ee h.
sm70n2227-2025 25/5/06 16:02 Página 228
measu ed a iables be ween g oups we e es ed using
he non-pa ame ic K uskal-Wallis es , a e es ing
he da a o no mali y using he Kolmogo o -
Smi no es and Le ene’s es o homogenei y o
a iances. Mul i a ia e analyses (clus e ) we e ca -
ied ou using he PRIMER package (Cla ke and
Go ley, 2001) and o uni a ia e analyses (mean com-
pa ison h ough K uskal Wallis) he BMDP was used
(Dixon, 1983).
RESULTS
Mo phological a ia ion o he adula ee h
The adula o P. au an ioma gina a is de ined as
ha ing he o mula 8-15 x 4.2.0.2.4 (Figs. 3E, F).
The ou ma ginal ee h a e quad angula , wi hou
cusps and he size dec eases ou wa ds (Fig. 3F; Fig.
4C). The wo in e nal ee h a e hama e, as he inne
SCI. MAR., 70(2), June 2006, 227-234. ISSN: 0214-8358
ONTOGENETIC AND INTRASPECIFIC RADULAR CHANGES OF P. AURANTIOMARGINATA • 229
FIG. 3. – SEM pho og aphs o he adula and p e- adula in di e en specimens o P.au an ioma gina a. A. Olde po ion o he adula in an
indi idual 1.5 mm long. B. De ail o a bi id oo h in he adula o an indi idual 1.5 mm long. C. Radula and p e- adula o a specimen 4 mm
in leng h. D. De ail o he p e- adula po ion om a ju enile 4 mm in leng h. E-F. Adul adula.
sm70n2227-2025 25/5/06 16:02 Página 229
oo h is smalle and hinne han he second one;
hey ha e an apical cusp and a spu app oxima ely in
he middle o he oo h (Figs. 3E, F; Figs. 4G, J).
The e is no achidian oo h. This adula pa e n,
conside ed as he adul ype o he species, appea s
in almos all he specimens s udied. Howe e , some
mo phological di e ences a e seen in specimens
smalle han 4 mm in leng h.
Specimens o 3-4 mm in leng h ha e he adula
di ided in o wo po ions, wi h mo phological a i-
a ions o he ee h. The an e io ee h ows, which
a e he oldes , ha e he ma ginal ee h p o ided by
an enla ged basal pa and a ilamen ous cusp (Fig.
3D; Fig. 4B); he la e al ee h ha e he adul mo -
phology, al hough he spu s a e e y small (Figs. 4E,
I). The newe ows ha e he adul pa e n desc ibed
be o e (Fig. 3C; Figs. 4F, J). In his si ua ion, he
an e io po ion o he adula is conside ed as a p e-
adula, acco ding o P u o -Fol (1926). Specimens
smalle han 3 mm lack he adul adula pa e n
(Fig. 3A), o i only appea s in he las ows o he
ibbon. The ma ginal ee h a e ilamen ous, lacking
SCI. MAR., 70(2), June 2006, 227-234. ISSN: 0214-8358
230 • I. MARTÍNEZ-PITA e al.
FIG. 4. – On ogene ic a ia ions in he adula and p e- adula. A, B and C, a ia ion o he ma ginal ee h in animals smalle han 3 mm (A),
3-4 mm in leng h (B) and bigge han 4 mm (C). D, E, F and G, a ia ion in he ou e la e al oo h in animals smalle han 3 mm (D), 3-4 mm
in leng h in he p e- adula po ion (E) and adula po ion (F) and indi iduals bigge han 4 mm (G). H, I and J, a ia ion o he inne la e al
oo h in animals smalle han 3 mm (H), 3-4 mm in leng h (I) and indi iduals bigge han 4 mm (J). The alue o he scale ba s a e 10mm in
H, 20mm in A, B, D, E and I, 100mm in F and 200mm in C, G and J.
sm70n2227-2025 25/5/06 16:02 Página 230
he basal enla ged po ion; some ma ginal ee h ha e
he ip bi id (Figs. 3A, B; Fig. 4A). The ou e la e -
al ee h lack he spu and he cusp is p o ided by a
longi udinal u ow (Fig. 4D). The inne la e al ee h
ha e he adul mo phology, bu he spu s a e e y
small (Fig. 4H).
Rela ion be ween he leng h o he animal and
he size o he adula and ee h
Figu e 5 shows he ela ion be ween he leng h o
he animals and he leng h o he adula. The ela ion
be ween he leng h o he specimens and he mean
alue leng h o he ee h is shown in Figu e 6. Bo h
g aphs show a s a is ically signi ican posi i e co e-
la ion. The leng h o he adula inc eases wi h he
g ea e leng h o he animal (Fig. 5). This line is
desc ibed by he equa ion Y = 0.69 + 0.04x, wi h he
coe icien o co ela ion ( ) equal o 0.91 (n = 141,
P <0.001). The leng h o he ou e la e al oo h (con-
side ed he mean alue leng h o all ows o each spec-
imen) inc eases as he leng h o he animal inc eases
(Fig. 6). The eg ession line is Y = 154.36 + 5.99x;
= 0.92 (n =137, P <0.001).
Va ia ion o oo h size along he adula wi h
p e- adula
Besides he on ogene ic mo phological a ia ion,
he ee h o he p e- adula pa di e in size om
he adul pa . Figu e 7 shows he size o he ou e
la e al ee h along he adula ibbon in specimens
up o 4 mm in leng h. The ee h along he p e- adu-
la ows a e no ably smalle han he ee h p esen in
adul ows.
Specimens wi h only p e- adula ee h ha e all
he ou e la e al ee h clea ly smalle han hose ani-
mals wi h adul ee h. In specimens wi h p e- adula
and adul adula ows, he size o he ee h inc eas-
es quickly om he olde ows (p e- adula po ion)
o he newe ows (wi h adul ee h pa e n). In ani-
mals 4 mm in leng h he p e- adula may be p esen
o absen . When only adul ee h ows a e p esen ,
he size o he ee h coincides wi h hose o la ge
specimens.
Radula di e ences be ween he numbe o
ows and he leng h o he specimens
Figu e 8 shows he ela ion be ween he numbe
o ows and he leng h o he animals. In his g aph-
ic i is possible o see ha specimens smalle han 4
mm ha e mo e ee h ows han la ge specimens.
SCI. MAR., 70(2), June 2006, 227-234. ISSN: 0214-8358
ONTOGENETIC AND INTRASPECIFIC RADULAR CHANGES OF P. AURANTIOMARGINATA • 231
Animal leng h (mm)
0 102030405060
Radula leng h (mm)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Y=0.69+0.04X
FIG. 5. – Rela ion be ween he animal’s leng h and he leng h o he
adula.
Animal leng h (mm)
0 102030405060
Mean ee h leng h (µm)
100
150
200
250
300
350
400
450
500
Y=154.36+5.99X
FIG. 6. – Rela ion be ween he animal’s leng h and he mean leng h
o he ou e la e al oo h.
Row
0 5 10 15 20 25 30 35
Tee h leng h (µm)
0
20
40
60
80
100
120
140
160
180
1.5 mm
2 mm
3 mm
4 mm
4 mm´
4 mm´´
FIG. 7. – Size o he ou e la e al oo h in each ow o he adula ib-
bon in specimens up o 4 mm in leng h. The a ow indica es he
beginning o he adula pa . Indi iduals 4 mm in leng h wi hou a
p e- adula a e included.
sm70n2227-2025 25/5/06 16:02 Página 231

The e is a signi ican dec ease in he numbe o ows
in specimens la ge han 4 mm, and a e his, he
numbe o ows inc eases e y slowly wi h inc eas-
ing animal size. The sudden dec ease coincides wi h
he disappea ance o he p e- adula in he animal.
On ogene ic a ia ion o he adula in
P. au an ioma gina a
Figu e 9 shows he esul o clus e ing he speci-
mens using he UPGMA me hod and Euclidean dis-
ance. The h ee measu ed a iables ( adula leng h,
numbe o ows and he mean alues o oo h leng h)
we e used o es ablish he a ini ies among speci-
mens. Animals wi h a p e- adula we e no included
in his analysis. Clus e analysis dis inguished h ee
g oups, which ep esen h ee animal sizes: 4-10
mm, 11-22 mm and 23-48 mm in leng h. The non-
pa ame ic K uskal-Wallis es showed s a is ically
signi ican di e ences among he h ee g oups o
he h ee measu ed a iables (Table 1).
Figu e 10 shows ha he mean alues o he ou e
la e al oo h o each adula ow e eal ha he h ee
g oups ha e di e en in e al sizes, which a e la g-
SCI. MAR., 70(2), June 2006, 227-234. ISSN: 0214-8358
232 • I. MARTÍNEZ-PITA e al.
Adul leng h (mm)
1 10 100
Row numbe
0
5
10
15
20
25
30
Row
0123456789101112
Tee h leng h (µm)
100
150
200
250
300
350
400
4-10 mm
11-22 mm
23-48 mm
FIG. 8. – Rela ion be ween he leng h o he animal and he numbe
o ows p esen in he ibbon, he loga i hmic scale has been used
o he leng h o he animal.
0
1
2
3
4
5
4 -10 mm
Euclidean dis ance
11 - 22 mm 23 - 48 mm
FIG. 9. – The h ee di e en g oups esul ing om he clus e ing using he UPGMA me hod and he Euclidean dis ance. Animals wi h a
p e- adula a e no included.
FIG. 10. – Mean alues o he ou e la e al ee h wi h he s anda d
e o o he mean in each adula ow along he ibbon in he h ee
di e en g oups.
sm70n2227-2025 25/5/06 16:02 Página 232
e in he animals 23-48 mm in leng h. Howe e , he
size cu es along he ibbon a e simila o he h ee
g oups. Thus, he oldes ee h a e smalle because o
wea ; he size o he ee h inc eases owa ds he
newe ows, wi h a maximum leng h in he six h o
eigh h ows. The las ows o he adula (which a e
he mos ecen ly o med) ha e smalle ee h, which
a e s ill de eloping.
DISCUSSION
Al hough he opis hob anchs ha e a ce ain wide
ange in he numbe o ee h pe ow, his pa ame e is
equen ly used as a diagnos ic ea u e a a speci ic
le el. Some a icles ha e been published ha aim o
examine he in aspeci ic a iabili y ela ed o he
adula o mula (i.e. Beeman, 1963; Be sch, 1976;
Fe ei a, 1977). All o hem desc ibed a di ec co e-
la ion be ween he size o he body and he numbe o
adula ows. Howe e , we ha e ound in P. au an-
ioma gina a ha he co ela ion is no obse ed i
specimens smalle han 4 mm a e conside ed, because
in animals up o 3-4 mm he numbe o adula ows
is no ably highe han ha o specimens la ge han 4
mm. Simila si ua ions we e desc ibed in he species
o Polyce a idae T iopha ca alinae (Coope , 1863), T.
macula a MacFa land, 1905, Tambja ceu ae Ga cía-
Gómez and O ea (1988) and T. ma bellensis Schick
and Ce e a, 1998 (Fe ei a, 1977; Ocaña e al.,
2004). Fo bo h species o T iopha, Fe ei a (1977)
desc ibed he p esence o a di ec unc ion be ween
he size o he adul specimens and he numbe o
ows. Howe e , his au ho indica ed ha e y small
specimens (smalle han 10 mm in leng h) ha e a
much g ea e numbe o ows han he adulae o
ma u e indi iduals (Fe ei a, 1977). In Tambja ceu ae
and T. ma bellensis he numbe o adula ows is also
highe in specimens smalle han 10 mm long (Ocaña
e al., 2004).
P u o -Fol (1926) desc ibed he p esence o he
so called p e- adula o dis inguish he i s ee h
ows o Polyce a quad ilinea a om he es o he
ows de eloped du ing he ju enile s age. The shape
o he ee h o he p e- adula is di e en om he
adul ee h o he adula ibbon.The species o
Tambja s udied by Ocaña e al. (2004) also show
some changes which coincide wi h he idea o he
p esence o a di e en de elopmen al pa e n o he
adula in ela ion o he size (o age) o he speci-
mens. Du ing he de elopmen o animals om he
ju enile o adul s ages he adula changes in he
numbe o ows and he shape o he ee h, inde-
penden ly o he species. This pa e n o adula wi h
p e- adula, coincides wi h ha ound in P. au an-
ioma gina a. Acco ding o he idea o P u o -Fol
(1926), who desc ibes a p e- adula in Polyce a
quad ilinea a, he obse a ions o Fe ei a (1977)
and Ocaña e al. (2004) in he T iopha, and Tambja
species espec i ely, and in P. au an ioma gina a
(p esen pape ), i is possible o suppose ha in
Polyce a idae he e is a ansi ion in adula mo -
phology om young o adul animals ha akes
place apidly. This a ia ion could be ela ed o a
change o die no con i med ye by analysis o
s omach con en s.
Finally, based on ou s udy he ollowing conclu-
sions can be made abou P. au an ioma gina a:
1) The leng h o he adula inc eases wi h he
leng h o he specimen.
2) The leng h o ou e la e al ee h inc eases wi h
he leng h o he animal. Fu he mo e, he ee h
along he p e- adula ows a e clea ly smalle han
adul ee h.
3) Specimens smalle han 4 mm wi h a p e- adu-
la ha e mo e ee h ows han hose la ge han 4 mm.
4) In specimens wi hou a p e- adula, he numbe
o ee h ows inc eases as he leng h o he animal
inc eases.
5) Acco ding o he on ogene ic a ia ions
obse ed in he adula o P. au an ioma gina a, ou
g oups o specimens a e dis inguished, which ep e-
sen di e en animal sizes: smalle han 4 mm wi h
a p e- adula, 4-10 mm, 11-22 mm and 23-48 mm.
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ONTOGENETIC AND INTRASPECIFIC RADULAR CHANGES OF P. AURANTIOMARGINATA • 233
TABLE 1. – Resul s o he K uskal Wallis es o he h ee measu ed a iables: he adula leng h, numbe o ows and mean leng h o he ee h
in he h ee g oups es ablished h ough he Clus e analysis.
Mean ± S anda d de ia ion K uskal Wallis
4-10 mm 11-22 mm 23-48 mm (S a is ic)
Radula leng h 0.94 ± 0.16 1.46 ± 0.22 2.00 ± 0.27 805.8***
Numbe o ows 8.93 ± 0.77 10.00 ± 0.96 11.20 ± 1.27 45.1***
Mean leng h o he ee h 178.55 ± 36.69 261.49 ± 26.88 333.61 ± 26.08 104.9***
*** p<0.001
sm70n2227-2025 25/5/06 16:02 Página 233
The e is no clea eason o explain he clus e sepa-
a ion o he di e en g oups; howe e , ou own
obse a ion leads us o hink ha his sepa a ion
could be ela ed o eeding s a egies o ood ype.
P obably, he e is a change in die in P. au an-
ioma gina a du ing i s g ow h, which would be
ela ed o he ype o adula ee h p esen . The
smalles specimens (1.5 o 4 mm in leng h) we e
ound on he b yozoan Sessibugula ba osoi López
de la Cuad a and Ga cía-Gómez, 1994 (pe s. obs.),
which leads us o hink ha his species could be i s
p ey die . Howe e , he la ge specimens (which
include he h ee emaining clus e g oups) we e
ound ea ing he b yozoan Bugula ne i ina
(Linnaeus, 1758) and T icella ia occiden alis
(T ask, 1857).
ACKNOWLEDGEMENTS
We wish o exp ess ou g a i ude o Au o a
Mon e o who helped us o ex ac mos o he adu-
lae. We also hank D . Sánchez Tocino and D .
Ocaña o p o iding he specimens om La
He adu a and SEM pho og aphs.
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