CLYPEINA BESICI PANTIÆ FROM KARAVANKE MOUNTAINS, SLOVENIA 237
GEOLOGICA CARPATHICA, 54, 4, BRATISLAVA, AUGUST 2003
CLYPEINA BESICI PANTIÆ (CHLOROPHYTA, DASYCLADALES)
FROM THE RAIBL BEDS
OF THE WESTERN KARAVANKE MOUNTAINS (SLOVENIA)
TEA KOLAR-JURKOVEK and BOGDAN JURKOVEK
Geological Survey of Slovenia, Dimièeva 14, 1001 Ljubljana, Slovenia; email@example.com; firstname.lastname@example.org
(Manuscript received June 14, 2002; accepted in revised form March 11, 2003)
Abstract: The find of Clypeina besici from the Raibl beds of the Western Karavanke Mts, Slovenia, provides supple-
mentary information to the morphology of this Carnian dasyclad species. Segments of thalli (consisting of some tens of
whorls), and numerous isolated whorls are preserved as singles, couples and triplets. Besides, two more dasyclad species
that differ from C. besici are provisionally described with open nomenclature.
Key words: Upper Triassic, Slovenia, Karavanke Mts, Raibl beds, morphology, Dasycladales, Clypeina besici.
Thalli of algal order Dasycladales are often encrusted with
biogeneously secreted calcium carbonate. They were impor-
tant rock builders and are notable for reconstructions of past
depositional environments. Living representatives mainly in-
habit littoral (infralittoral) zones of tropical and subtropical
seas, and, according to Meyen (1987), they do not grow at
depths below 60 m, but occasionally they can reach 70 to
90 m (de Castro 1997). The size of the dasyclads depends on
environmental conditions, and in fossil forms it mostly ranges
from a few to 100 mm, yet some representatives are known to
attain greater tallus length (Berger & Kaever 1992). Due to ar-
ticulation in many species, the dasyclad skeleton is subject to
postmortem disintegration into segments or isolated whorls.
Dasycladales are mostly observed and studied in petrographic
thin sections. Finds of isolated Triassic dasyclad taxa, either
segments of thalli or whorls, are relatively rare. Kristan-Toll-
mann (1988) reported only some finds of isolated whorls or
fragments of whorls of Clypeina besici Pantiæ collected from
different Alpine localities and from Burma; she also noted
that her material included an iron oxide cast of a dissolved
whorl from Turkey. This algal species has been first described
by Pantiæ (1965) from the Carnian of Montenegro, Yugosla-
via. C. besici is a well known species due to its wide distribu-
tion across the Tethys. According to Ott (1974) and Kristan-
Tollmann (1988), it is the zone fossil of the Cordevolian and
Julian, but it continues up into the Tuvalian. It is an index spe-
cies of the taxon-range zone with a confirmed Carnian range
The material from the Karavanke Mts, Slovenia (Fig. 1),
provides supplementary information about the morphological
features, both the external and internal structure, of the spe-
cies C. besici. It contains several segments of thalli embeded
in slabs of marly limestone. Among them there is also a seg-
ment of thallus, over 7 cm long, of exceptional preservation
illustrated here for the first time (Fig. 2). There are also many
other preserved parts of thalli or their casts. Furthermore, in-
soluble microfossil residues yield more than a hundred isolat-
ed whorls of the genus Clypeina, preserved as singles, couples
and also some triplets.
Stratigraphy of the Raibl beds with Clypeina
in the Kouta Nappe, Western Karavanke Mts
The Carnian Raibl beds of the Kouta Nappe north of
Mojstrana attain thickness of some hundred meters (Jurk-
ovek 1987a,b). It is mainly made up of dark-grey limestone
and marly limestone with intercalations of marls. The lime-
stone is platy to thin-bedded, and according to its texture,
biomicrite prevails. An internal lamination can be observed in
some limestone beds, but rarely calcarenitic or brecciated
beds also occur. In the upper part of the Carnian succession,
Fig. 1. Geographical sketch map showing position of the studied lo-
238 KOLAR-JURKOVEK and JURKOVEK
which is characterized by frequent Clypeina occurrences (seg-
ments of thalli and isolated whorls), individual breccia layers
occur, 30 to 40 cm thick. Abundant thin-shelled posidonias
occur in certain beds (also in beds with Clypeina), whereas
plant fossils of the genus Voltzia (Dobruskina et al. 2001),
and well preserved fish with the prevailing genus Peltopleu-
rus are frequent in more marly beds. In the lower part of the
sequence, ammonoids Trachyceras aonoides or Austrotra-
chyceras austriacum were found (Ramov 1993). Conodont
apparatus Nicoraella? budaensis Kozur & Mostler was also
recovered from the succession, 15 m below the beds with al-
gae (Kolar-Jurkovek & Jurkovek 1999).
A detailed lithostratigraphic comparison of the Carnian
beds with Clypeina in the Kouta Nappe of Karavanke Mts
with the developments of the Raibl Group (Gruppo di Raibl)
in the typical locality of Western Julian Alps (Assereto et al.
1968; Lieberman 1978, 1980; De Zanche et al. 2000) has not
been done yet and will be the aim of further studies.
Clypeina besici Pantiæ in Granier & Deloffre 1995, non 1965
(Fig. 2, Fig. 3.19)
For synonymy see Granier & Grgasoviæ (2000, p. 2930).
Material and repository: Segments of thalli (BJ
1288A, BJ 1288B, BJ 1411B) and casts of thalli (BJ 1412)
embedded in the limestone slabs. Isolated whorls, over 60,
have been recovered from the microfossil residues collected
in the samples GeoZS 3023, GeoZS 3055, GeoZS 3088.
The illustrated and examined specimens marked with BJ
have been catalogued and deposited in the Jurkovek Paleon-
tological collection at Dol pri Ljubljani (Slovenia), registered
at the Ministry of Culture of the Republic of Slovenia and the
Natural History Museum of Slovenia. Microfossil material
marked with GeoZS has been stored at the Geoloki zavod
Slovenije (Geological Survey of Slovenia).
Description: The species displays a cylindrical thallus
with wide central cavity. Whorls, bowl shaped, are arranged
at distinct intervals. Simple, undivided branches are arranged
in a single row. Branches are evenly distributed along the cal-
careous skeleton. In the proximal part, branches are closely
set parallel to the main axis. Distal part of the branches has ra-
dial arrangement and they become gradually thinner towards
the distal end. Central cavity is wide; its diameter is constant
along the main axis.
Remarks: Segment of thallus, over 7 cm long (BJ 1288A
Fig. 2), of exceptional preservation is preserved on the
limestone slab. It has 66 almost completely preserved whorls
and at least 3 more partly preserved whorls, the whole set of
whorls being interrupted at three places. They are embedded
in a sediment to a different degree and are lying in different
positions; some are still set in a life position, showing lateral
surface of the whorls touching each other, either in part or
hardly so; in places, the whorls are turned and shown in trans-
versal view; in between there are whorls in oblique position
and they partly cover each other. The number of branches is
Fig. 2. Clypeina besici Pantiæ, external aspect of the thallus (without
uppermost portion) in exceptional preservation from Carnian of the
Karavanke Mts, Slovenia, sample BJ 1288A. Scale bar = 1cm.
difficult to count precisely; however, in the whorls with the
orientation that allows counting, and depending on the preser-
vation, there are 20 branches per whorl. The longest measured
free part of the branch is 0.64 mm long.
CLYPEINA BESICI PANTIÆ FROM KARAVANKE MOUNTAINS, SLOVENIA 239
Fig. 3. 19: Clypeina besici Pantiæ, Carnian, Karavanke Mts, Slovenia. 1, 2, 4, 6, 8: external aspect of the whorls or their fragments (1,8
upper views, GeoZS 3023; 2 lateral view, GeoZS 3023; 3 lateral view, GeoZS 3055; 4,6,7,9 lower views, GeoZS 3055). 5: external
aspect of the branch, GeoZS 3023. 10, 11: Clypeina sp. B, Carnian, Karavanke Mts, Slovenia external aspect of the whorls, lower views,
GeoZS 3023. Scale bar = 100 µm except in fig. 9 = 200 µm.
240 KOLAR-JURKOVEK and JURKOVEK
Fig. 4. Clypeina? sp. A, Carnian, Karavanke Mts, Slovenia. 14: external aspect of the whorls. 1ad specimen shown in a upper, b
lateral, c oblique lateral, d lower views, GeoZS 3055; 2 lower view, GeoZS 3023; 3 lower view, GeoZS 3055; 4 oblique lat-
eral view, GeoZS 3055). 5: internal view, GeoZS 3023. Scale bar = 100 µm.
CLYPEINA BESICI PANTIÆ FROM KARAVANKE MOUNTAINS, SLOVENIA 241
Measured dimensions in mm: Outer diameter (D):
0.52.0; Inner diameter (d): 0.150.7; Distance between two
consecutive whorls (h): 0.21.0; Number of branches in a
whorl (w): 1020.
Clypeina? sp. A
Material: Over 100 isolated whorls (GeoZS 3023,
GeoZS 3055, GeoZS 3088).
Description: Whorls have double row of densely spaced
branches. Both rows of branches clearly differ from each oth-
er. The lower row is marked by branches that outnumber the
branches from the upper one, minimal difference is 2. There-
fore, the diameter of the branches in the upper row is greater.
The branches are connected with the central cavity by means
of relatively large pores; those of the lower row are smaller
and more densely spaced than those arranged in the upper
row, which are larger and oval in shape. Both rows of branch-
es stand under the same angle to the main axis.
Remarks: The specimens are characterized by whorls
with two rows of branches distinguished by their size and
number. The thallus of this species probably had the arrange-
ment of whorls with two alternating rows of branches. There-
fore it markedly differs from Clypeina besici Pantiæ, which
has branches arranged in a single row. The thallus of the latter
species reveals whorls with uniform branches that are in their
proximal part parallel to the main axis.
At present, it is not possible to ascertain if the double-row
whorls are segments containing two successive whorls what
could be inferred from longer segments of thalli with more con-
secutive whorls. Therefore, such forms are tentatively attrib-
uted to the genus Clypeina and described as Clypeina? sp. A.
Measured dimensions in mm: Outer diameter (D):
0.451.0; Inner diameter (d): 0.150.4; Distance between two
consecutive whorls (h): 0.250.5; Number of branches in a
whorl (w): upper row: 818, lower row: 1020.
Clypeina sp. B
Material: 14 isolated whorls (GeoZS 3023, GeoZS 3055,
Description: The skeleton, or part of it, bears whorls
with a large central cavity. Undivided branches, quite delicate
and with constant diameter, are densely set in a single row. In
places, branches are so dense that they partly cover adjoining
ones. The branches in the form of arches embrace the main
Comparison: Whorls determined as Clypeina sp. B dif-
fer from other isolated whorls from the same samples both in
their shape, orientation, and greater number of the branches
per whorl. Whorls of another two recognized species, Clypei-
na? sp. A and Clypeina besici Pantiæ, have radially, or partly
radially, oriented branches. The whorls of Clypeina sp. B re-
semble the whorls of the Eocene Clypeina marginoporella
Michelin; however, the branches of the latter species are
standing parallel to the main axis.
Measured dimensions in mm: Outer diameter (D):
0.71.0; Inner diameter (d): 0.30.8; Distance between two
consecutive whorls (h): 0.250.45; Number of branches in a
whorl (w): 1422.
Micropaleontological study of the Raibl beds revealed
the presence of the alga C. besici in the upper part of the sec-
tion below Mt Jepca. The collected material includes several
segments of thalli (the longest measuring over 7 cm) in the
slabs of marly limestone, and it substantially adds to the better
understanding of the morphology of this dasyclad alga. The
samples, after acid treatment for conodonts, also produced
isolated whorls of this alga. C. besici is an index species of the
taxon-range zone with confirmed Carnian range (Grgasoviæ
1997). The samples of the examined section with dasyclad
alga also yield conodont apparatus Nicoraella? budaensis Ko-
zur et Mock (Kolar-Jurkovek & Jurkovek 1999), and thus
indicating a possibility for correlation between the algal and
conodont Triassic zonations. In addition, the samples also
yielded two more dasyclad species that differ from C. besici
and are provisionally described with open nomenclature.
Acknowledgments: The authors thank Prof. Dr. I. Guiæ
(University of Zagreb, Croatia) for his suggestions and for
reading the earlier draft of the manuscript. The paper benefit-
ed from critical comments of the GC reviewers, Prof. Dr. Ioan
Bucur, Prof. Dr. Branko Sokaè and Dr. Jan Soták. Scanning
electron micrographs of the specimens illustrated on Fig. 3
and 4 were taken on JEOL JSM by Prof. Dr. K. Dralar (Uni-
versity of Ljubljana, Slovenia). This work was supported by
the Ministry of Education, Science and Sport of the Republic
of Slovenia. This is a contribution to IGCP Project 467 Tri-
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