Hetgol~nder Meeresunters. 34, 91-110 (1980)
Morphological and ecological investigations on
sympatric IApophrys species (Blenniidae, Pisces)
C. D. Z a n d e r
Zoologisches Institut und Zoologisches M u s e u m ;
Universit&t, Martin-Luther-King-Platz, D-2000 Hamburg, Federal R e p u b l i c of G e r m a n y
ABSTRACT: The three syntopic blenniids Lipophrys canevai, L. adriaticus, and L. dalmatinuswere
investigated off Katarina Island near Rovinj, Yugoslavia, in regard to their habitats and food
organisms. The shallow, sheltered rocky sea shore turned out to be the characteristic habitat for L.
dalmatinus and L. adriaticus, whereas L. canevai also inhabits surf-exposed biotopes. The overlap
of the microhabitats was below 50 %. Algae are the main food of all three species with respect to
biomass, but harpacticoids dominated in L. adriaticus and especially L. dalmatinus when considering abundance of food organisms. Overlap of trophic niches was high (80 %) between L. canevai
and L. adriaticus but lower (< 45 %) between L. dalmatinus and the other two species. Morphological studies considered external morphology, pigmentation, and anatomy of eyes, including the
closely related, cave-dwelling L. nigriceps. This species reveals special adaptations to life in dimly
lit biotopes: reduction of the basic melanophore pigmentation, development of clinging organs, and
enlargement of eyes and lenses combined with an effective ratio of retinal elements and modes of
accommodation. It is concluded that the four species are members of one "Lebensorttyp" (Riedl,
1966) of which L. nigriceps has superimposed the basic characteristics with specializations to a
greater and the other three species to a lesser degree.
INTRODUCTION
Blenniid fish of the g e n u s Lipophrys are w i d e l y d i s t r i b u t e d in the M e d i t e r r a n e a n
Sea: L. trigloides (L.), L. canevai ( S t e i n d a c h n e r & Kolombatovic), L. dalmatinus (Steind a c h n e r & Kolombatovic), L. adriaticus (Vinciguerra), a n d L. nigriceps (Vinciguerra).
W h e r e a s L. trigloides i n h a b i t s s t e e p rocks in t h e surf a r e a (Zander, 1972b), a n d L.
nigriceps s e a c a v e s or o t h e r d i m l y lit b i o t o p e s (Abel, 1959; Z a n d e r & J e l i n e k , 1976;
Z a n d e r & H e y m e r , 1977), the other t h r e e s p e c i e s are f o u n d in the shallow, a l g a e - c o v e r e d
littoral zone. L. adriaticus and dalmatinus h a v e not b e e n f o u n d y e t t h r o u g h o u t the e n t i r e
M e d i t e r r a n e a n Sea; the former does not s e e m to occur in t h e Gulf of Lion or the N o r t h
African coast (Zander, 1972b).
Hence, the q u e s t i o n arises c o n c e r n i n g the d e g r e e to w h i c h L. canevai, L. adriaticus
and L. dalmatinus are a d a p t e d to different e c o l o g i c a l n i c h e s in the s a m e biotope. T h e
p r e s e n t i n v e s t i g a t i o n s relate m o r p h o l o g i c a l a d a p t a t i o n s of Lipophrys s p e c i e s to t h e i r
r e s p e c t i v e habitats; L. nigriceps, w h o s e h a b i t a t a n d p r e y w e r e i n v e s t i g a t e d f o r m e r l y
(Zander & J e l i n e k , 1976; Z a n d e r & H e y m e r , 1977), is i n c l u d e d a n d m e n t i o n is m a d e of L.
velifer of S e n e g a l . T h o u g h t h e h a b i t a t s a n d food of L. canevai a n d L. dalmatinus h a v e
b e e n d e s c r i b e d from o t h e r r e g i o n s of the M e d i t e r r a n e a n S e a (Zander, 1972b; Z a n d e r
© Biologische Anstalt Helgoland
0174-3597/80/0034/0091/$ 02.00
92
C.D. Zander
i
½km
35
°
Fig. 1. Sites of investigation off Rovinj, Yugoslavia {Adriatic Sea}. 31: Katarina Island; 34: Red
Island; 35: Banjole Island
& Bartsch, 1972), t h e s e s t u d i e s d i d not c o n s i d e r s y n t o p y a n d p o s s i b l e interspecific
competition. O n t h e Y u g o s l a v i a n A d r i a t i c coast w e f o u n d the n e c e s s a r y conditions for
such i n v e s t i g a t i o n s : A l l five M e d i t e r r a n e a n Lipophrys s p e c i e s could b e o b s e r v e d a n d
c o l l e c t e d at different i s l a n d s off Rovinj in the y e a r s 1973 a n d 1975.
MATERIAL A N D M E T H O D S
T h e m a i n i n v e s t i g a t i o n site w a s t h e s o u t h e r n coast of K a t a r i n a Island, w h e r e a
s y n t o p y of L. canevai, L. adriaticus a n d L. d a l m a t i n u s w a s most e v i d e n t {Fig. 1, No. 31}.
For c o m p a r a b l e reasons, L. canevai i n d i v i d u a l s from R e d I s l a n d ( = Crveni Otok, Fig. 1,
No. 34) also w e r e studied. T h e fish w e r e c a u g h t w i t h h a n d nets d u r i n g s k i n - d i v i n g a n d
f i x e d in 4 % f o r m a l i n w i t h i n a n hour. After m e a s u r i n g a n d w e i g h i n g the guts w e r e
r e m o v e d a n d the contents t a x o n o m i c a l l y a s s e s s e d a n d counted. A l g a e w e r e c o u n t e d b y
e s t i m a t i n g b i t e s a c c o r d i n g to the w i d t h of the m o u t h of the r e s p e c t i v e fish. C o n t r a r y to
the o t h e r c o m p o n e n t s , the d r y w e i g h t of a l g a e w a s e v a l u a t e d d i r e c t l y from m a t e r i a l
i n g e s t e d b y the fish.
For e s t i m a t i n g the p o t e n t i a l l y a v a i l a b l e food a p h y t a l s a m p l e of an a r e a of 50 cm 2
w a s s c r a t c h e d from t h e s u b s t r a t e (Fig. 2). It w a s t a k e n u p in a p l a s t i c b a g w h i c h w a s
c l o s e d u n d e r water, y i e l d i n g a n a l m o s t q u a n t i t a t i v e p h y t a l s a m p l e w i t h its fauna. A l g a e
and fauna were approximately identified, counted and dry weights were determined.
The r e s p e c t i v e m e a n w e i g h t s w e r e u s e d for e s t i m a t i n g the b i o m a s s t a k e n u p b y the fish.
F u l l n e s s i n d e x (Hureau, 1969), f e e d i n g s e l e c t i v i t y (Berg, 1979), a n d n i c h e o v e r l a p
(Colwell & F u t u y m a , 1971) w e r e e v a l u a t e d .
In a d d i t i o n to s p e c i m e n s from the Rovinj area, L. dalmaUnus from F r a n c e (Banyulss u r - M e r a n d M e z e ) a n d S p a i n (Tarragona) as w e l l as L. velifer from S e n e g a l (Isle de
Gor~e) w e r e i n v e s t i g a t e d for m o r p h o l o g i c a l studies. T h e h e a d s of the fish w e r e p r e p a r e d
for h i s t o l o g i c a l t r e a t m e n t s , cut in 10-/m~ s e r i a l sections a n d s t a i n e d with Pasini. The
I n v e s t i g a t i o n s o n Lipophrys s p e c i e s
93
0
-WL
D
O,5
X ~ t D ~-~.-
Phi'asarape/
ll ~
X,
Dr
1'
m
6
Fig. 2. Transverse section of the investigation site at Katarina Island: (A) Lipophrys adriaticus, (D) L.
dalmatinus, (E) L. canevai, (I) Parablennius incognitus, (T) L. trigloides, (X) P. sphynx
m e a s u r e m e n t s a n d c o u n t s of t h e r e t i n a l e l e m e n t s w e r e p e r f o r m e d u s i n g a n e y e - p i e c e
micrometer.
ECOLOGY
OF THE LIPOPHRYS SPECIES
Habitat
T h e i n v e s t i g a t i o n s i t e o n t h e s o u t h e r n c o a s t of K a t a r i n a (Fig. 1, N o 31) w a s e x p o s e d
to full s u n l i g h t . A s t e e p s l o p e c h a n g e d to a n a l m o s t p l a n e r o c k y t e r r a c e at 0.5 m b e l o w
w a t e r l e v e l (Fig, 2), T h e s t e e p s l o p e w a s u n c o v e r e d d o w n to 0.2 m b e l o w w a t e r l e v e l ,
t h e n o v e r g r o w n b y b a l a n o i d s a n d M y t i l u s a n d f r o m 0.3 m b y a l g a e , e s p e c i a l l y Ulva. T h e
r o c k t e r r a c e o n l y o c c a s i o n a l l y e x h i b i t e d l a r g e r a l g a e s u c h a s Cystoseira or Padina b u t
w a s t o t a l l y c o v e r e d b y a d e l i c a t e C1adophora c a r p e t . E v e r y w h e r e h o l e s of p i d d o c k s of
various sizes w e r e found, w h i c h are u s e d by Mpophrys a n d o t h e r b l e n n i i d s as s p a w n i n g
places.
Table 1. Distribution of 3 IApophrys species to different microhabitats of the investigated biotope at
Katarina Island
Incline and d e p t h
Steep wall 0-25 cm
Steep wall 25-50 cm
Rock terrace <:50 cm
Rock terrace 50-100 cm
Rock terrace > 100 cm
n
Density in the main microhabitat (m 2)
L. canevai
3
10
5
8
=
=
=
=
11.5
38.5
19.2
30.8
0
26
4
%
%
%
%
L. adriaticus
13
3
5
2
= 56.5 %
= 13.0 %
= 21.7 %
= 8.7 %
0
24
8
L. dalmatinus
0
0
4 = 28.6 %
4 = 28.6 %
6 = 42.8 %
14
2
94
C.D. Zander
Table 2. Microhabitat overlap of 3 Lipophrys species; ranges may stretch from 0 (no overlap) to 1
(total overlap)
Species
L. canevai
L. adriaticus
L. adriaticus
L. dalmatinus
0.412
-
0.478
0.304
Table 3. Flight distance and main flight direction of 3 Lipophrys species
Species
L canevai
L. adriaticus
Flight distance
Flight direction
middle
upwards
very low
upwards
L, dalmatinus
middle
all directions
W h e r e a s only L. adriaticus a n d L. c a n e v a i w e r e o b s e r v e d at the steep wall, all 3
species i n h a b i t e d the rock terrace, a l b e i t at different f r e q u e n c i e s (Table 1). U s i n g these
results, a n e v a l u a t i o n of the overlaps i n m i c r o h a b i t a t s d e m o n s t r a t e s that in every case
the v a l u e s are b e l o w 50 % a n d are lowest b e t w e e n L. adriaticus a n d L. dalmatinus
(Table 2).
The periods of activity t u r n e d out to b e d e p e n d e n t o n full s u n s h i n e i n L. adriaticus
a n d to a lesser d e g r e e i n L. dalmatinus, w h e r e a s L. c a n e v a i w a s observed at shadowy
sites as well. These results confirm former i n v e s t i g a t i o n s (Zander, 1972b). D u r i n g rainy
w e a t h e r all L. adriaticus a n d most L. d a l m a t i n u s i n d i v i d u a l s stayed i n their r e s i d e n c e
holes. Distance a n d direction of escape are also different i n the three species (Table 3).
Food
p o t e n t i a 11 y a v a i 1 a b 1 e f o o d. The analysis of the phytal s a m p l e s t a k e n at
0.6 m b e l o w w a t e r l e v e l o n the rock terrace (Fi 9. 2) s h o w e d a b r o a d s p e c t r u m of p o t e n t i a l
food organisms. The i n v e s t i g a t e d area of 50 cm 2 c o n t a i n e d a total b i o m a s s of 1886 m 9 W a
w h i c h consisted m a i n l y of a l g a e (93 %; Fig. 3). A m o n 9 f a u n a l elements, bivalves (71%)
d o m i n a t e d over p o l y c h a e t e s (10 %) a n d g a m m a r i d s (6 %), w h i c h were followed b y
m e i o f a u n a o r g a n i s m s such as harpacticoids (4 %) or foraminifers (3 %) (Fi9. 3). In regard
to a b u n d a n c e (total n u m b e r of i n d i v i d u a l s = 4150), the m e i o f a u n a d o m i n a t e d b y far,
c o n s i s t i n g of harpacticoids (40 %), n e m a t o d e s (16 %) a n d foraminifers (12 %). The most
n u m e r o u s m a c r o f a u n a w e r e b i v a l v e s (13 %) a n d polychaetes (10 %). The degree to
w h i c h this food source is u s e d b y the ZApophrys species will b e a n a l y s e d i n the next
section.
F o o d u p t a k e. The total l e n g t h s a n d w e t w e i g h t s of the e x a m i n e d fish are shown
i n F i g u r e 4. L. c a n e v a i is the largest a n d h e a v i e s t species, a n d L. dalmatinus, the smallest
k n o w n b l e n n i i n species, is the lightest.
The fullness index, the relative q u a n t i t y of i n g e s t e d food, is very high in L. canevai
(6.4), b u t lower i n L. adriatlcus (2.0) a n d i n L. d a l m a t i n u s (2.7) (Fig. 4}. These values
correspond to the m e a n b i o m a s s of the food i n g e s t e d by one fish (Table 4}.
I n v e s t i g a t i o n s o n Lipophrys s p e c i e s
Total
95
Fauna only
Wd
"-
~
Me~otouno
,-n
Fig, 3. P o t e n t i a l a v a i l a b l e food f r o m a p h y t a l s a m p l e . A b o v e : d r y w e i g h t , b e l o w : n u m b e r s ; left:
f a u n a a n d flora, right: f a u n a o n l y
C
:
A
, I
*
I
x
~"
m
D
range
6
mm
C
A
'
-n
,t
!
I
~[--]
I
TL
'
.
LU
)
6
C
i
,
I
½
I
3
I
I
gWw
i .....
,
A
D
6
I
I
~
'
16
°/oF~ll
Fig. 4. Miller g r a p h s of total l e n g t h s (above), wet w e i g h t s (middle) a n d fullness i n d e x e s (below) of
three Lipophrys species. CA} L. adriaticus, (C) L. canevai, (D) L. dalmatinus; m: m e a n error, s:
s t a n d a r d deviation, x: m e a n v a l u e
C. D. Z a n d e r
96
Table 4, Mean values of food ingested by 3 Lipophrys species
Ratios
L. canevai
Ww mg (related to gut content)
W d mg (related to potentially available food)
WwFt~d
n
L. adriaticus L. dalmatinus
142.8
6.01
23.76
10
10.8
0.60
18.29
18
8.1
0.48
16.88
10
T h e a b u n d a n c e a n a l y s i s g i v e s a m e a s u r e for f e e d i n g activity of the fish a n d also
s h o w s w h a t c o m p o n e n t s a r e f e d o n most f r e q u e n t l y (Fig. 5). W h e r e a s h a r p a c t i c o i d s
d o m i n a t e d in t h e s m a l l L. adriaticus a n d L. dalmatinus, L. canevai fed p r i m a r i l y on
a l g a e . H e n c e the r e s u l t s of Z a n d e r & Bartsch (1972) can b e c o n f i r m e d in p r i n c i p l e . Since
t h e p r o p o r t i o n of a l g a e s e e m e d u n e x p e c t e d l y h i g h in L. canevai, five s p e c i m e n s from
Red I s l a n d (Fig. 1, No. 34) w e r e c o m p a r e d in this respect. T h e y p r e f e r r e d a l g a e as well,
b u t not in such l a r g e q u a n t i t i e s as t h e K a t a r i n a p o p u l a t i o n , a n d h a d t a k e n u p a h i g h
p r o p o r t i o n of h a r p a c t i c o i d s a n d cypris l a r v a e a l o n g w i t h s o m e m a c r o f a u n a c o m p o n e n t s
(Fig. 5).
T h e food of L. nigriceps, w h i c h is not s y n t o p i c w i t h the other t h r e e species, h a d b e e n
i n v e s t i g a t e d p r e v i o u s l y in s p e c i m e n s from the Banjole grotto (Fig. 1, No. 35) ( Z a n d e r
& H e y m e r , 1977). T h e y h a d fed p r i m a r i l y on aufwuchs, w h i c h c o n s i s t e d not only of
a l g a e b u t also h y d r o z o a n s a n d b a l a n o i d s (Fig. 5).
T h e b i o m a s s of food o r g a n i s m s s h o w e d t h a t a l g a e w e r e the m a j o r c o m p o n e n t for all
t h r e e species, a c c o u n t i n g for 98 % in L. canevai (Fig. 6). T h e two s m a l l e r s p e c i e s r e p l a c e
t h e a l g a e i n c r e a s i n g l y b y f a u n a l e l e m e n t s t h e l a r g e s t p r o p o r t i o n b e i n g harpacticoids. L.
L co neva i
L. adrioticus
L. nigriceps
L. dalma~inus
O.Sv. Kalorina (31)
1
other
H~ocorida
Crveni O~ok (3/.)
O.Bon]ole (35)
Fig. 5. Abundance analysis (numbers) of gut contents of three Lipophrys species; above: populations of Katarina Island, below: other populations
I n v e s t i g a t i o n s on
Lipophrys s p e c i e s
97
dalmatinus h a d fed on m a c r o f a u n a such as g a m m a r i d s a n d p o l y c h a e t e s in l a r g e r
q u a n t i t i e s (Fig. 6).
A f r e q u e n c y a n a l y s i s gives i n f o r m a t i o n on h o w r e g u l a r l y p a r t i c u l a r food o r g a n i s m s
are t a k e n up b y a fish p o p u l a t i o n , b u t g i v e s no i n f o r m a t i o n a b o u t q u a n t i t i e s (Berg, 1979;
Zander, 1979a). A l g a e a r e fed on b y all L. canevai a n d L. adriaticus (Fig. 7), a n d all L.
dalmatinus h a d i n g e s t e d h a r p a c t i c o i d s . L. adriaticus f r e q u e n t l y fed on h a r p a c t i c o i d s ,
a n d L. dalmatinus on a l g a e a n d p o l y c h a e t e s (Fig. 7).
The e v a l u a t i o n of f e e d i n g s e l e c t i v i t y p r o v i d e s e v i d e n c e of the p r e f e r r e d or a v o i d e d
food. Since only dry w e i g h t s b u t no a b u n d a n c e d a t a w e r e a v a i l a b l e for the a l g a e from
the p h y t a l sample, this p a r a m e t e r w a s e v a l u a t e d r e l a t i v e to the b i o m a s s of the s i n g l e
L. c a n e v a i
L. a d r i a t i c u s
I Oammafld.~
J
I Bivalvia ~
/
Others
' " - - - - - - " I atherMeiofauna ~
L. d a l m a t i n u s
J
/
~
/
atherMeiofauna v
J
Fig. 6. Biomass analysis (dry weights) of gut contents of three IJpopbrys species from Kataril,a
Island
Algae
L. canevai
L. adriaticus
L. dalmatinus
IIIIIIII111111111111111111111111111111111111111111
Ostracada
J
Turbellaria
Cypris larvae
--1
Nemertini
111
Gastropoda
1miTT1
Balanoidea
Gammaridae
I
Bivalvia
[]
Caprellidae
Polychaeta
~
Anisopoda
Halacarida
TT]T[]-[][T[~
IIIIIIIIltllllll
Chironornidae
I
Harpacticoidea IIIIIII11111111111111111111111III1[1111
Fish eggs
J
,
o
~'o
16O./o
6
lp
so%
Fig. 7. Frequency analysis (percent occurrence) of gut contents of three Lipophrys species (L.
canevai, L. adriaticus, L. dalmatinus) from Katarina Island
98
C.D. Zander
c o m p o n e n t s (Fig. 8). A l l t h r e e s p e c i e s p r e f e r r e d a n i s o p o d s a n d fish eggs; the s m a l l e r
s p e c i e s L. adriaticus a n d L. dalmatlnus also c o n s u m e d m e i o f a u n a (harpacticoids, h a l a c a rids, ostracods) a n d s o m e m a c r o f a u n a l e l e m e n t s (gastropods, p o l y c h a e t e s , chironomids}.
G a m m a r i d s , w h i c h a r e p r e f e r r e d b y L. canevai a n d L. dalmatinus, w e r e a v o i d e d b y L.
adriaticus totally. P r e f e r r e d food of o n l y a s i n g l e fish s p e c i e s w e r e : a l g a e b y L. canevai,
n e m e r t i n e s a n d b a l a n o i d s b y L. adriaticus, a n d t u r b e l l a r i a n s b y L. dalmatinus (Fig. 8).
T h e different f e e d i n g h a b i t s of t h e t h r e e Llpophrys s p e c i e s m a y also b e e x p r e s s e d b y
the specific n i c h e o v e r l a p c o n s i d e r i n g t h e b i o m a s s of i n g e s t e d food (Table 5). W h e r e a s L.
canevai a n d L. adriaticus s h o w a h i g h d e g r e e of o v e r l a p (80 %), L. dalmatinus is in less
c o m p e t i t i o n w i t h its relatives, f e e d i n g on a h i g h p e r c e n t a g e of m e i o f a u n a (Table 5).
L. a d r i a t i c u s
L.dolmatinus
L. c a n e v a i
[
Algae
Turbellorio
---I, OD
I
Nemertini
]
Gastropoda
Bivaivja
- OQ ~ "
- ~:x> <-"-
- C O ~'--
-q
-q
Palychaela
Halacarida
-co<--
-I
[
Her pacticoid.
]
-3
Ostracoda
Balanoidea
- oO Or-"
FF-
-I
-oo e-,',','I
Garnmaridae
--q
--q
Ceprellidae
Anisopoda
_ o0 (-=-
]
I
Chironomidae
--->oo
Fish eggs
I
--]'co
--~,oo
o
Fig. 8, Feeding selectivity of three Lipophrys species from Katarina Island. O: prey in identical
percentages in the gut and in the potentially available food; CD: prey absent in the phytal sample;
GD: offered food not preyed on by the fish
-
I n v e s t i g a t i o n s on L i p o p h r y s s p e c i e s
99
Table 5. Food overlap of 3 Lipophrys species; range from 0 (no overlap) to 1 (total overlap)
Species
L. canevai
L. adriaticus
L. adriaticus
L. dalmatinus
0.792
-
0.332
0,444
MORPHOLOGY
External morphology
As the e x t e r n a l m o r p h o l o g y of L. c a n e v a i a n d L. d a l m a t i n u s has b e e n d e s c r i b e d
previously (Zander, 1972b, 1973), that of L. a d r i a t i c u s and L. n i g r i c e p s will be o u t l i n e d
here. These two species also h a v e long a n d c o m p r e s s e d bodies; L. n i g r ~ c e p s has a
strikingly n a r r o w h e a d and b e l l y (Fig. 9, i0). T h e l o w e r rays of the p e c t o r a l fin e n d in
little hooks, 4 in L. a d r i a t i c u s and 6 in L. n i g r i c e p s - the g r e a t e s t count in b l e n n i i d s until
\
J
/
Icm
Fig. 9. General aspect and melanophore colouring of Lipophrys adriaticus. Right: Ventral view of
head and front body (drawing: A. Dowling)
!
lcm
I
Fig, t0, General aspect and melanophore colouring of Lipophrys nigriceps. Right: Ventral view of
head and front body (drawing: A. Dowling)
100
C.D. Zander
now. The two parts of the pelvic fins of L. nigriceps are very long a n d deeply notched,
they e n d obtusely a n d not a c u t e l y as in the other species (Fig. 10). In L. adriaticus the
pelvic fins are stronger a n d not as d e e p l y n o t c h e d as i n L, nigriceps (Fig. 9). The rays of
the a n a l fins of both species e n d in little hooks. A t h i n cuticula on the v e n t r a l parts of the
fins was o b s e r v e d only in L. adriaticus.
The lateral line of L, adriaticuspossesses only a few pores n e a r the h e a d region, This
o r g a n is r e p e a t e d l y i n t e r r u p t e d a n d is without a n y pores i n L. nigriceps,
Pigmentation
The basic colour p a t t e r n b u i l t u p by m e l a n o p h o r e s a n d x a n t h o p h o r e s a n d the
specific colour p a t t e r n consisting of all types of chromatophores are to be distinguished.
Species of Lipophrys are k n o w n to display a n ethological colour c h a n g e as well as a
g e o g r a p h i c a l v a r i a b i l i t y (Zander, 1969, 1972b). D u r i n g the s p a w n i n g s e a s o n the males
have a h e a d m a s k with a b l a c k crown a n d b r i l l a n t l y coloured cheeks (Abel, 1962;
Zander, 1975).
The crown of L, adriaticus is c o n t i n u e d on the b a c k of the whole body, i n t e r r u p t e d
there by m a n y light spots (Fig. 9). The other parts of the h e a d a n d body are yellow with
some m e l a n o p h o r e s . L. nigriceps, on the other h a n d , only has b l a c k patterns o n the head,
the front body a n d more seldom on the h i n d body, m e l a n o p h o r e s of the basic pattern
...:-"
BodruTVTK
~.~____~
~
Fig. 11. Variability of melanophore patterns in 7 Lipophrys nigriceps from the Banjote grotto and
one from Bodrum, Turkey (drawing: A. Dow]ing}
I n v e s t i g a t i o n s on Lipophrys s p e c i e s
101
being a b s e n t (Figs 10-12). The m a l e s ' h e a d m a s k is a v e r y broad b l a c k crown w h i c h runs
over the hind o p e r c u l u m onto the belly. The b o d y p a t t e r n consists of black, i n t e r r u p t e d
lines or spots, often only w e a k l y visible and v e r y v a r i a b l e in e a c h s p e c i m e n (Fig. 11).
The r e m a i n i n g b o d y of L. nigriceps is b r i g h t red, w h e r e a s the h e a d has y e l l o w cheeks.
N o n - s p a w n i n g m a l e s a n d all f e m a l e s h a v e a m a r b l e d h e a d i n s t e a d of the h e a d m a s k
(Fig. 11).
Table 6. Number of melanophores in Lipophrys species from different body regions; area: 0.1 mm 2
Species
L. nigriceps - red
L, nigriceps - b town
L. canevai
Beginning of
pectoral fin
Beginning of
soft dorsal fin
Caudal
peduncle
0
20
24
0
16
20
4
19
19
O n l y one of 45 L. nigriceps i n d i v i d u a l s c a u g h t in the B a n j o l e grotto was b r o w n i n s t e a d
of red and w a s at first confused w i t h L, canevai (Fig. 12). A c o m p a r i s o n of m e l a n o p h o r e
counts along the b a c k of L. canevai a n d L. nigriceps is c o m p i l e d in T a b l e 6. T h e s e results
did not y i e l d d i f f e r e n c e s b e t w e e n L. canevai and b r o w n L. nigriceps, w h e r e a s
m e t a n o p h o r e s are almost totally a b s e n t in the red ones (Fig. 12).
b
C
t
Fig. 12. Photographs of skin below the beginning of soft dorsal fin rays, showing melanophore
patterns~ (a) Lipophrys canevai, (b) red L. nigriceps, (c) brown L. nigriceps
102
C.D. Zander
Eyes
For five L i p o p h r y s s p e c i e s a n e y e i n d e x w a s e v a l u a t e d b y m e a n s of t h e q u o t i e n t e y e
d i a m e t e r : total l e n g t h (Fig. 13). T h e l o w e s t v a l u e s w e r e f o u n d in L. canevai, s o m e w h a t
h i g h e r ones in L. adriaticus, L. v e l i f e r a n d L. dalmatinus, a n d v e r y h i g h ones in L.
nigriceps. T h e r e g r e s s i o n of i n d i c e s to the total l e n g t h w a s c a l c u l a t e d in o r d e r to test the
p o s s i b i l i t y of a n a l l o m e t r i c g r o w t h of t h e e y e (Fig. 13). W h e r e a s t h e e y e s of L. dalmatinus
a n d m a y b e L. c a n e v a i g r o w a l m o s t i s o m e t r i c a l l y , l a r g e r s p e c i m e n s of t h e other t h r e e
s p e c i e s s h o w r e l a t i v e l y l o w e r e y e d i a m e t e r s t h a n s m a l l s p e c i m e n s . This is d e m o n s t r a t e d
v e r y c l e a r l y in the g r a p h for L. adriaticus (Fig. 13). The e y e s of L. n i g r i c e p s are also
c h a r a c t e r i z e d b y t h e i r p r o m i n e n t size w i t h r e s p e c t to this regression.
c:
I
m
L U,
D
I
,
V
I
A
I---'[~,,,
I i
.......r - F l
~:
t
"
I I,I
I
FT]
N
t
.....
;
'
I
[
Itl
LU
J
:
t
0,04
0,06
0105
0,07 Index
Index
J
0,07-
0,05
0,03
v
50
)
7C)rnm TL
Fig. 13. Miller graph (above} and regression to body length of eye indices of 5 I.u'pophrys species.
(A) L. adriaticus, (C) L. canevai, (D} L. dalmatinus, (N) L. nignceps, (V) L. velifer
Externally, t h e e y e s of four s p e c i e s i n v e s t i g a t e d m o r e i n t e n s i v e l y e x h i b i t a crescentm o o n - s h a p e d a p h a c i c a p e r t u r e of t h e p u p i l , w h i c h s e e m s to b e l a r g e s t in L. nigriceps.
F u r t h e r m o r e , the v e r y l a r g e l e n s of this s p e c i e s is conspicuous. The r e t i n a e of all 4
s p e c i e s h a v e a coarse surface structure (Fig. 14). In L. canevai, L. adriaticus a n d L.
d a l m a t i n u s 1-2 t e m p e r o d o r s a l s w e l l i n g s a n d s h a l l o w e l e v a t i o n s in the c e n t r a l p a r t are
c l e a r l y visible. T h e l a t t e r structures form t w o b a n d - s h a p e d a r e a s in L. canevai. In L.
n i g r i c e p s the t e m p e r o d o r s a l s w e l l i n g is o n l y s h a l l o w ; the r e t i n a s h o w s a r o u n d d e p r e s sion in the c e n t r e in w h i c h the l e n s p r o b a b l y m a y b e r e t r a c t e d (Fig. 14).
Investigations on Lipophrys species
103
1
ts
D
md
Fig. 14, Structure of retinae of 4 Lipophrys species; a: area, rod: m e d i a l depression, rf: retinal
fissure, ts: t e m p e r o d o r s a l s w e l l i n g {other a b b r e v i a t i o n s s e e Fig. 13)
Table 7. Relative lens d i a m e t e r a n d n u m b e r of retinal e l e m e n t s in 4 Lipophrys s p e c i e s
Structure or
region of eye
Relative l e n s
diameter
Upper m a r g i n
Receptors
Bipolars
G a n g l i o n cells
Area/swelling
Receptors
Bipolars
G a n g l i o n cells
Lower m a r g i n
Receptors
Bipolars
G a n g l i o n cells
L. canevai
L. adriaticus
L. dalmatinus
L. nigriceps
medial temporal medial temporal medial temporal medial temporal
0.428
-
0.503
-
0.556
-
0.607
-
2-3
6
2
3
7
3
1-2
4
1
2
9
3
2
5
2
2
8
3
1-2
3
1
1-2
5
2
2
11
3
5
24
6
2
12
3
7
22
5
2
13
4
6
24
5
2
8
2
5
20
6
2
6
1
2
6
1
1-2
6
1
2
7
1-2
2
6
1
2
5
2
1-2
4
1
1-2
5
1
104
C.D. Zander
A n e x a m i n a t i o n of histological serial sections p r o v i d e d data o n the relative lens
d i a m e t e r (quotient l e n s d i a m e t e r to eye diameter). This i n d e x is lowest i n L. canevai a n d
i n c r e a s e s i n the other species to the h i g h e s t v a l u e i n L. nipriceps (Table 7). The optic axis
of L. nigriceps" eye is l o n g e r v e n t r a l l y t h a n i n the m e d i a l a n d dorsal part (Fig. 15): ramp
r e t i n a (Walls, 1967). This m i g h t p o i n t to a further possibility for a c c o m m o d a t i o n i n this
species. O n the contrary, the other three species show a p r o l o n g a t i o n of the dorsal axis
C
A
m
1 rnm
Fig. 15. Schematic cross sections of eyes of 4 Lipophrys species, at upper right: enlarged cones of
every retina; ck: cornea conjunctiva, cp: cornea propria, 1: lens, p: melanophore, r: retina (other
abbreviations see Fig. 13)
I n v e s t i g a t i o n s on Lipophrys s p e c i e s
105
(Fig. 15). The e y e p i g m e n t r e a c h e s far onto t h e c o r n e a of L. canevai, L. adriaticus a n d L.
dalmatinus, b u t not in L. nigriceps ( Fig. 15).
The r e t i n a e p o s s e s s m o r e receptors, b i p o l a r a n d g a n g l i o n cells in the t e m p e r o d o r s a l
s w e l l i n g s t h a n i n the c e n t r a l a r e a s or in t h e m a r g i n a l r e t i n a e (Fig. 15, T a b l e 7). W i t h
respect to its s h a l l o w area, L. nigriceps differs from t h e o t h e r s p e c i e s in h a v i n g o n l y 8
b i p o l a r a n d 2 g a n g l i o n cells in o n e row. T h e ratio of b i p o l a r to g a n g l i o n cells is m o s t l y
low (except in L. adriaticus) a n d t h e r e f o r e s u i t a b l e for g o o d r e s o l v i n g p o w e r . In this
r e s p e c t L. nigriceps h a s t h e most a d v a n t a g e o u s v a l u e s in t h e t e m p e r o d o r s a l s w e l l i n g
(Table 7).
The n u m b e r of r e c e p t o r s is also l o w e s t in L. nigriceps (Table 8). T h e ratio of cones to
rods in this s p e c i e s is, w i t h o n l y s l i g h t d e v i a t i o n s , 1:1. T h e cones, on t h e o t h e r h a n d ,
d o m i n a t e in the t e m p e r o d o r s a l s w e l l i n g s of L. adriaticus a n d L. dalmatinus as w e l l as in
the a r e a of L. canevai, w h e r e a s the t e m p e r o d o r s a l s w e l l i n g of L. canevai p o s s e s s e s m o r e
rods (Table 8). A s t r i k i n g l y h i g h n u m b e r of r e c e p t o r s is f o u n d in t h e a r e a of L.
dalmatinus, in contrast to the o t h e r species.
The size of the cones v a r i e s in the four species: T h e l a r g e s t o n e s a r e o b s e r v e d in L.
nigriceps, the s m a l l e s t in L. dalmatinus (Fig. 15). T h e s e results c o r r e s p o n d o n l y in the
latter s p e c i e s to b o d y size, since the cones of L. canevai are still s m a l l e r t h a n those of L.
adriaticus. It w a s not p o s s i b l e to c o m p a r e the rods in size, as t h e s e w e r e c o v e r e d b y
p i g m e n t in the m i c r o s c o p i c sections a n d o n l y c o u l d b e r e c o g n i z e d b y t h e i r nuclei.
Table 8. Ratio of rods to cones in 50/an retina of 4 l.u'pophrys species
Species
Upper
margin
L. canevai
L. adriaticus
L. dalmatinus
L. nigriceps
9:8
6.5:7
6.5:9
4:5
Medial
Area
10:13
13:13.5
15:17.5
11:11
Lower
margin
Upper
margin
Temporal
Swelling
Lower
margin
9:9
11:8
9.5:11
5:6.5
10:10.5
7:6.5
8:9
7:7
16,5:15
7:17
15.5:20
9:11
6.5:8
10:8
10:11
8.5:7
DISCUSSION
The Lipophrys s p e c i e s i n v e s t i g a t e d d i s p l a y not o n l y i n t e r s p e c i f i c d i f f e r e n c e s b u t
also some c o m m o n patterns. T h e l a t t e r a r e t h o s e factors w h i c h m a y l e a d to i n t e r s p e c i f i c
c o m p e t i t i o n in the case of syntopy. S i n c e L. velifer is not d i s t r i b u t e d in t h e M e d i t e r r a n e a n S e a it will b e n e g l e c t e d in this discussion. L. nigriceps, w h i c h i n h a b i t s d i m l y lit
biotopes, is a l l o t o p i c w i t h L. canevai, L. adriaticus a n d L. dalmatinus; t h e r e f o r e t h e
e c o l o g i c a l d i s c u s s i o n w i l l b e c o n c e n t r a t e d on the l a t t e r t h r e e species.
Habitat
The h a b i t a t s of L. canevai a n d L. dalmatinus in t h e Rovinj a r e a do not differ from
sites formerly i n v e s t i g a t e d (Abel, 1962; Z a n d e r , 1972b). T h e classification of L. canevai
106
C . D . Zander
as a p e r m a n e n t cave dweller (Riedl, 1966) m a y be due to it having b e e n confused with
"brown" L. nigriceps. According to the results obtained the characteristic habitat of L,
adriaticus lies 0.1-0.5 m below the water level among steep rocks with little algae
coverage. Coast lines which are exposed to heavy surf are probably avoided (klydophoby); concerning sites in the open sea, L. adriaticus was only found in sheltered
habitats like the entrance channel of the Banjole grotto (Zander & Jelinek, 1976).
Food
Although some similarities exist, each of the 3 syntopic species has characteristic
feeding habits. The primary reasons lie in the different body sizes of the fish. Hence,
meiofauna (especially harpacticoids) plays the greatest part in the diet of L. dalmatinus.
Parallel to the decreasing importance of this component for L. adriaticus and especially
L. canevai, the proportion of a l g a e increases. Gammarids, known to be p r e y e d on by all
investigated blenniins, are absent in L. adriatic"as which had fed on relatively large
quantities of anisopods. L. adriaticus and L. dalmatinus preferred 11 and 10 components
of the potentially a v a i l a b l e food, respectively; L. canevai consumed only 4 components,
of which a l g a e not only m a d e up the main biomass but also caused a high fullness index.
Previous investigations (Gibson, 1968; Zander & Bartsch, 1972) showed lower proportions of algae in L. canevai and L. dalmatinus than in the Katarina population. Until now
only Parablennius sanguinolentus and P. parvicornis, among blenniins, were known to
feed exclusively on algae (Gibson, 1968; Zander, 1979b).Though algae m a d e up 75 % of
L. adriaticus' food, the species did not prefer this component. Nevertheless, there is a
high d e g r e e of overlap of ingested food b e t w e e n L. canevai and L. adriaticus, probably
caused by the high algae uptake. Comparing the three species with allotopic Lipophrys,
it becomes evident that L. nigriceps differs by feeding on 50 % sessile animals and
algae, and L. trigloides by preying on large quantities of bivalves and gammarids
(Zander & Bartsch, 1972; Z a n d e r & Heymer, 1977).
Morphology
L. nigriceps possesses 6 small hooks on the inferior rays of the pectoral fins, more
than in all other investigated b l e n n i i d s (L. trigloides has only 5; Zander, 1973). Furthermore, L. nigriceps differs in the shape of ventral fins, which end obtusely and not acutely
as in its relatives. Regarding the narrow body L. nigriceps resembles L. dalmatinus,
whereas L. canevai and L. adriaticus possess broader heads and bodies. The lateral line
is mostly r e d u c e d in L. dalmatinus and L. nigriceps but to a lesser degree in L. canevai
and L. adriaticus.
Having only m o d e r a t e l y strong ventral and inferior pectoral fin rays, L. adnaticus
does not show the adaptations to life in the surf zone that L. trigloides does. The degree
of reduction of its lateral line also gives evidence of adaptation to calmer areas. Hence, L.
adriaticus is restricted to sheltered biotopes though living n e a r the water surface. The
preferred biotopes of L. nigriceps, caves and grottos (Abel, 1962; Zander & Jelinek,
1976), are at least sheltered in the m i d d l e and rear sections (Riedl, 1966). The surprisingly large n u m b e r of hooks on the pectoral fins m a y be an adaptation of orientation to the
substrate, since L. nigriceps often moves b e l l y - u p on the ceilings of caves and therefore
must safeguard itself against falling down.
I n v e s t i g a t i o n s on Lipophrys s p e c i e s
107
O n l y in L. nigriceps c o u l d no m e l a n o p h o r e s of t h e b a s i c c o l o u r i n g b e d e t e c t e d . T h e i r
absence, t o g e t h e r w i t h the p r e s e n c e of r e d cells, is r e s p o n s i b l e for t h e c h a r a c t e r i s t i c c a v e
colouring of the body. The o b s e r v a t i o n of one b r o w n s p e c i m e n d e m o n s t r a t e s that t h e
gene(s) for the b a s i c m e l a n o p h o r e s h a v e not b e e n lost in this p o p u l a t i o n . Specific
m e l a n o p h o r e p a t t e r n s are, on the o t h e r h a n d , p e r m a n e n t l y v i s i b l e in this species. It
shows a m a r b l e d h e a d , s t r i k i n g l y i d e n t i c a l w i t h t h e p a t t e r n of Tripterygion melanurus,
w h i c h also h a s a r e d b o d y a n d is a c a v e d w e l l e r ( Z a n d e r & H e y m e r , 1976, 1977). T h e
m i m e t i c r e l a t i o n s h i p of t h e s e two s p e c i e s is u n d e r l i n e d b y t h e i r s o u t h e r n s u b s p e c i e s . L.
nigriceps portmahonis a n d T. melanurus melanurus, w h i c h h a v e a b l a c k t a i l s p o t l a c k i n g
in the n o r t h e r n s u b s p e c i e s , L. nigriceps nigriceps a n d T. melanurus minor ( Z a n d e r
& H e y m e r , 1976, 1977). At s p a w n i n g t i m e the L. nigriceps ~ ~ possess, l i k e o t h e r
Lipophrys species, a b l a c k a n d y e l l o w h e a d m a s k (Abel, 1962; Z a n d e r , 1975), w h e r e a s
Tripterygion melanurus ~ ~ t h e n differ in that t h e i r h e a d s a r e t o t a l l y b l a c k l i k e o t h e r
Tripterygion s p e c i e s ( Z a n d e r & H e y m e r , 1976).
The e y e s of L. nigriceps differ s t r i k i n g l y from t h o s e of the o t h e r Lipophrys species.
T h e y t u r n e d out to b e the l a r g e s t in r e l a t i o n to b o d y size a n d to p o s s e s s t h e l a r g e s t
lenses; t h e y show a v e n t r a l r a m p r e t i n a in contrast not o n l y to the o t h e r 3 Lipophrys b u t
also to m a n y other fish w h i c h h a v e a d o r s a l one (Munk, 1970). T h e n u m b e r of r e t i n a l
e l e m e n t s is low b u t t h e size of t h e c o n e s e x c e e d s t h a t of o t h e r Lipophrys. A l l t h e s e
p e c u l i a r i t i e s can b e e x p l a i n e d as m o r p h o l o g i c a l a d a p t a t i o n s to life in caves. T h e r a m p
retina is p r o b a b l y an a d a p t a t i o n to t h e c l i n g i n g on c a v e c e i l i n g s d i s c u s s e d above. T h e
b e s t a c c o m m o d a t i o n is therefore not p o s s i b l e in t h e d o r s a l r e t i n a for s e e k i n g food b u t in
the v e n t r a l p a r t for d e t e c t i n g e n e m i e s . This a s s u m p t i o n is in a g r e e m e n t w i t h the
o b s e r v a t i o n that L. nigriceps f e e d s p r i m a r i l y on a u f w u c h s a n d o n l y to a l e s s e r d e g r e e on
v a g i l e i n v e r t e b r a t e s . T h e m e d i a l d e p r e s s i o n in t h e retina, into w h i c h t h e l e n s c a n b e
w i t h d r a w n , is a further a c c o m m o d a t i o n p o s s i b i l i t y . T h e r e t i n a of this a r e a s e e m s to b e
fully efficient, c o n t r a r y to t h e d e p r e s s i o n f o u n d in the s a l a r i i n Istiblennius edentulus,
w h e r e all layers a r e r e d u c e d (Zander, 1974). T h e other s p e c i a l i z a t i o n s of the e y e of L.
nigriceps are v e r y p r o b a b l y a d a p t a t i o n s to the d i m l y lit b i o t o p e s . By the e n l a r g e m e n t of
the e y e a n d e s p e c i a l l y the lens a c o n c e n t r a t i o n of m a n y l i g h t rays onto the r e t i n a is
possible, thus c o m p e n s a t i n g for the low l i g h t i n t e n s i t y in t h e h a b i t a t , w h i c h is m o s t l y less
t h a n 1 % of the surface l i g h t ( Z a n d e r & J e l i n e k , 1976). A further a d a p t a t i o n in this
direction is s e e n on the cornea, w h e r e the p i g m e n t a t i o n r e c e d e s .
G e n e r a l l y , l a r g e cones in t h e r e t i n a of fish a r e a n i n d i c a t i o n for g o o d c a p a b i l i t i e s of
d a y l i g h t vision (Walls, 1967). In L. nigriceps t h e y m a y b e r e s p o n s i b l e for the a c u t e s h a p e
a n d colour vision w h i c h p l a y s a n i m p o r t a n t role in t h e social a n d s p a w n i n g b e h a v i o u r .
A d a p t a t i o n s to v i s i o n at low i n t e n s i t i e s of light, such as s m a l l rods, w e r e not d e t e c t e d
directly. O n the other h a n d , t h e ratio of b i p o l a r to g a n g l i o n c e l l s t u r n e d out to b e v e r y
a d v a n t a g e o u s for h i g h r e s o l v i n g p o w e r in L. nigriceps, in s p i t e of t h e f i n d i n g t h a t t h e
t e m p o r a l a n d m e d i a l s w e l l i n g s are v e r y flat in c o m p a r i s o n w i t h o t h e r Lipophrys species.
T h e r e m a y be a direct correlation of the p r e s e n c e of flat s w e l l i n g s , few b u t l a r g e cones
and the ratio of b i p o l a r to g a n g l i o n cells.
O n t h e e v o l u t i o n of t h e Lipophrys canevai s p e c i e s g r o u p
I n n i d i a t i o n of s p e c i e s h a s b e e n c o n s i d e r e d to b e a n i m p o r t a n t e v o l u t i o n a r y factor
(Ludwig, 1950). It i n v o l v e s the s i m u l t a n e o u s a d a p t a t i o n of m o r p h o l o g i c a l , p h y s i o l o g i c a l
108
C.D. Zander
Table 9. Combination of microhabitat and food overlap of 3 Lipophrys species; range from 0 (no
overlap} to 1 (total overlap}
Species
L. canevai
L. adriaticus
L. adriaticus
L. dalmatinus
0.571
-
0.398
0.367
and ethological characteristics of the population to its ecological niche and to the
competitive pressure of other species. The last factor will be greater the more the
competitor coincides with the occupier of the niche in morphology and physiology
(Remane, 1943). If competitors are lacking, a radiative a d a p t a t i o n to different niches may
occur, which leads to very different morphological and physiological characteristics in
the following evolutionary processes.
How should we j u d g e the i n v e s t i g a t e d L i p o p h r y s species in this respect? Apparently
the species L. canevai, L. adriaticus, L. dalmatinus, a n d L. n i g r i c e p s make up a very
young group; the close relationship was a c k n o w l e d g e d by Zander (1972a) and confirmed by osteological results (Bock, 1979). The two similar species, L. p h o l i s and L.
trigloides, are somewhat less closely r e l a t e d to the group mentioned, whereas L. velifer
may have a marginal position (Bock, 1979). Therefore it can be assumed that the L.
c a n e v a i species group evolved from a common ancestor which probably was not
identical to any of the recent species. This ancestor might have b e e n an inhabitant of the
shallow sheltered littoral, since 3 of 4 species are found exclusively in such habitats. It is
evident that further speciation led L. n i g r i c e p s to dimly lit biotopes, and L. canevai, by
extension of its ecological potential, a d d i t i o n a l l y into surf-exposed biotopes (Zander,
1972b). Only a partial a d a p t a t i o n onto steep rocks by L. adriaticus and onto horizontal
hard substrates in about 1-m depth by L. d a l m a t i n u s took place. These specializations
have gone further in L. d a l m a t i n u s than in L. adriaticus, since the former species is
absent among steep rocks (Table 1). In this microhabitat, L, adriaticus competes with L.
canevai, though the latter species g e n e r a l l y has its habitat in d e e p e r water and is less
abundant.
A specialization r e g a r d i n g i n d i v i d u a l food components was clearly recognized only
in L. n i g r i c e p s (aufwuchs; Zander & Heymer, 1977) and, to a lesser degree, in L.
d a l m a t i n u s (meiofauna). Therefore it is u n d e r s t a n d a b l e that the overlap in the trophic
dimensions of the niches occupied is relatively high b e t w e e n L. canevai and L.
adriaticus (Table 5).
A combination of the trophic a n d microhabitat niche dimensions was m a d e by
e v a l u a t i n g the geometrical m e a n s of the values given in Tables 2 and 5. The combined
overlap value of 57 % b e t w e e n L. c a n e v a i and L. adriaticus is still very high (Table 9}.
This means, that in spite of m a n y similarities, the syntopy of the 3 species is possible by
the existence of, for example, a surplus of p r e y and a sufficient n u m b e r of p i d d o c k holes
for h i d i n g a n d spawning.
The morphological specializations can be attributed more to the adaptation to
distinct microhabitats than to prey. Hence, it is conceivable that only after the microhabitat was chosen did the a d a p t a t i o n to morphology and prey begin. In L. n i g r l c e p s the
morphological specializations are very clearly visible: pigmentation, anatomy of the
I n v e s t i g a t i o n s on L i p o p h r y s s p e c i e s
109
eyes a n d p e c t o r a l fins w i t h 6 h o o k s for c l i n g i n g to t h e c e i l i n g s of caves. L. c a n e v a i
possesses only 3 hooks, w h i c h are, in contrast, sturdier t h a n in t h e o t h e r 3 s p e c i e s a n d are
suited for c l i n g i n g to t h e substrate in t h e surf z o n e (Zander, 1973}.
T h e m e m b e r s of the L. c a n e v a i s p e c i e s g r o u p m a y be c o n s i d e r e d to b e a " L e b e n s orttyp" (Riedl, 1966; m e a n i n g b i o t o p e - c o r r e l a t e d c o m m o n structures of a g r o u p of
r e l a t e d organisms} of the shallow, s h e l t e r e d r o c k y littoral. O n l y L. n i g r i c e p s has
d e v e l o p e d a d a p t a t i o n s to life in c a v e s w h i c h s u p e r i m p o s e on t h e b a s i c c h a r a c t e r i s t i c s of
this group. H e n c e , L. n i g r i c e p s r e p r e s e n t s the e c o l o g i c a l e q u i v a l e n t of the b e n t h i c s e a
cave d w e l l e r (Zander & H e y m e r , 1977}. S i n c e not only r e g r e s s i v e {pigmentation} b u t also
p r o g r e s s i v e e v o l u t i o n a r y p a t h w a y s a r e present, it is c o n c e i v a b l e that p r e d i s p o s i t i o n s
m a d e r a p i d s p e c i a t i o n possible.
D e r i v i n g from one " L e b e n s o r t t y p " , t h e d e v e l o p m e n t of m a n y different m o r p h o l o g i cal a n d p h y s i o l o g i c a l types w a s p o s s i b l e b y (I) a d a p t a t i o n of m o r p h o l o g i c a l characteristics to n e w a b i o t i c factors (e. g. e y e s of L. n i g r i c e p s to l o w l i g h t intensities}, a n d {2)
a d a p t a t i o n to biotic factors l i k e e x p l o i t a t i o n of different food sources (e. g. s m a l l b o d y
size of L. dalmatinus to m e i o f a u n a prey).
Acknowledgements. I am indebted to R. Ignacczak and H. Jelinek for help in the field investigations, to Dr. Z. Stevcic and Dr. D. Zavodnik (Institute Ruder Boscovic, Rovinj), to J. MSller-Buchner
for examining the phytal samples, A. Dowling for the histological preparations, and to Dr. P. Wirtz
for the specimens of Iu'pophrys velifer. I am grateful also to the Deutsche Forschungsgemeinschaft
for a travel grant [Za 44/4).
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