Geo.Cro.2-3-61-KB.pdf 129 � Felix Schlagintweit1 and Wolfgang Pavlik2 AB STRA CT Two taxa of halimedacean algae are recorded from the Upper Triassic lagoonal Dachstein Limestone (Norian-Rhae- tian) of the Hochschwab area in the south-eastern part of the Northern Calcareous Alps of Austria. They are described in open nomenclature as Halimeda? sp. 1 and Halimeda? sp. 2. In contrast to the widespread occurrence of dasycla- dalean algae, representatives of Halimedaceans are very rare. These fi ndings are the second record in the Northern Calcareous Alps since FLÜGEL (1975). Keywor ds: Calcareous algae, Halimedaceae, taxonomy, Triassic, Northern Calcareous Alps, Austria 1 Lerchenauerstr. 167, D-80935 München, Germany; (ef.schlagintweit@t-online.de) 2 Geologische Bundesanstalt, Neulinggasse 38, A-1030 Wien, Austria; (wolfgang.pavlik@geologie.ac.at) New fi ndings of halimedacean algae from the Late Triassic Dachstein Limestone of the Northern Calcareous Alps (Hochschwab Area, Styria, Austria) Geologia Croatica 61/2–3 129–133 3 Figs. Zagreb 2008 Geologia CroaticaGeologia Croatica � 1. INTRODUCTION Dasycladales (calcareous green algae), such as diplopores, are widespread in the Middle and Upper Triassic limestones of the Northern Calcareous Alps (e.g. PIA, 1920; OTT, 1967). They appear in “incredible abundance” and “were the Halim- eda of their time, ecologically speaking” (ELLIOTT, 1991, p. 127). Although there is a variety of genera assigned to halime- dacean algae with their fi rst records from the Middle Triassic as summarized recently by SENOWBARI-DARYAN & ZAM - PARELLI (2005), records of the genus Halimeda Lamouroux (or Boueina TOULA) from the Triassic are comparably rare worldwide, but also include one occurrence from the North- ern Calcareous Alps of Austria (see further below). In fact, even in the 1960’s, the Halimeda-Boueina couplet wasn´t known to occur in the Triassic, being fi rst known from the beginning of the Jurassic (e.g. JOHNSON, 1964). From the Triassic, their disarticulated segments were reported predom- inantly from lagoonal limestones, whereas almost all other Triassic halimedacean algae, often with bush-like growth forms, were described from reefal limestones (e.g. SENOWBARI- DARYAN & ZAMPARELLI, 2005). FLÜGEL (1975) re port ed on the occurrence of Boueina hochstetteri liasica LE MAITRE from the Norian-Rhaetian Dachstein limestone of the Gosau- kamm. Later, the age of the Boueina-bearing limestones was refi ned to the Norian (FLÜGEL, 1988). From the Norian-Rha - e tian of Western Thailand, FLÜGEL (1988) described the new species Boueina marondei, also recently discovered from the Upper Triassic of Iran (SENOWBARI-DARYAN & HAM A - DANI, 1999). Two further species have been established in recent times by DRAGASTAN et al. (2000) from the Rhae- tian of Hydra (Greece) as Halimeda helladica and Halimeda discreta. In this work, Boueina marondei Flügel was treated as belonging to the genus Halimeda. In conclusion, there are now up to four geographic records (Austria, Thailand, Iran and Greece) of localities of Triassic representatives of the genera Halimeda-Boueina. Geologia Croatica Geologia Croatica 61/2–3 130 In the framework of a karst-hydrologic project, coordi- nated by the Geological Survey of Austria (MANDL1 et al., 2002) representatives of halimedaceans tentatively ascribed here to the genus Halimeda LAMOUROUX, 1812 were dis - covered in two samples of Late Triassic limestones from the south-eastern part of the Northern Calcareous Alps of Austria (Fig. 1). Given the general rarity of Triassic halimedaceans, these fi ndings are briefl y described here, and represent the second record in the Northern Calcareous Alps since that of FLÜGEL (1975). 2. GEOLOGICAL OVERVIEW AND MATERIAL The Muerztal Alps of Styria being part of the southeastern Northern Calcareous Alps are dominated by Middle and Up per Triassic limestones and dolomites (e.g. SPENGLER, 1920; 1 MANDL, G.W. (project leader), BRYDA, G., KREUSS, O., MO- SER, M., PAVLIK, W., DECKER, K., DRAXLER, I., KRYSTYN, L. & PIROS, O. (2002): Erstellung moderner geologischer Karten als Grundlage für karsthydrogeologische Spezialuntersuchungen im Hochschwabgebiet: Folgeprojekt Eisenerz – Schwabeltal – Meß- nerin – Mitteralpe. Forschungsprojekt WA-4A F2000 & StA028n/ F2000 der MA31 Wiener Wasserwerke, des Amtes der steier märk- ischen Landesregierung und des Bundesministeriums f. Bildung, Wissenschaft & Kultur. – Unpubl. Final Report, Projektzeitraum 1. Juni 2000 – 31 Mai 2002, 211 p., Wien. LEIN, 2000; MANDL et al., 2002). In the Hochschwab area (or Hochschwab Unit) which forms part of the Muerztal Nap pe, Wetterstein Limestone (Ladinian-Middle Carnian) and Dach - stein Limestone (Norian-Rhaetian) are mostly prevalent. Both lithostratigraphic units may comprise both reefal and la goonal facies. Representatives of Halimedaceae were ob served in two samples: Sample WPA 61/98. This sample comes from the north- ern side of the Grasberg (1673 m), (see the topographic map of Austria 1:25.000 ÖK no. 101, Eisenerz, coordinates 645935/ 277850). According to the geological map 1:25.000 in MANDL et al. (2002), the Grasberg is built up of lagoonal Dachstein Limestone (Norian-Rhaetian). The occurrence of the dasycla- dalean alga Griphoporella curvata (GÜMBEL) provides evi - dence for a Norian-Rhaetian age (e.g. BARATTOLO et al., 1993), thus confi rming assignation to the Dachstein Lime- stone. The microfacies represent a biosparite (grain- to pack- stone). The sample contains Halimeda? sp. 1, dasycladalean algae, gastropods, foraminifera, peloids and aggregate grains and can be referred to an open-marine platform. Sample WPA 233/97. Sample locality is situated south of the Karlstein (2013 m) and southwest of the Hundsboden, topographic map of Austria 1:25.000 ÖK no. 102, Afl enz Kur - ort, coordinates 656615/274660. In this area, the boundary between the Wetterstein and Dachstein Limestones occurs. The microfacies represent a biosparite (grainstone). Sample WPA 233/97 contains Halimeda? sp. 2, calcareous algae, Fi gu re 1: Topographic map of sample locations WPA 61–98 and WPA 233–97 in the Hochschwab area of the Mürztal Alps, Austria. Geologia CroaticaFelix Schlagintweit and Wolfgang Pavlik: New fi ndings of halimedacean algae from the Late Triassic Dachstein Limestone... 131 gas tropods, remains of sphinctozoan sponges, crinoids, Tubi- phytes sp. and peloids. The sample can be refered to an open lagoon to back-reef facies. Direct stratigraphic dating of sample WPA 233/97 is not possible; because of the overall fi eld relationships and samples taken from the immediate surroundings, it is also referred to the Dachstein Limestone. 3. TAXONOMIC DESCRIPTIONS Before starting with the description of the Alpine material, some remarks on fossil halimedacean algae are vital. Algae today referred to the Halimedaceae (e.g. HILLIS, 1991) were formerly grouped within the Codiaceae, then afterwards in the Udoteaceae (e.g. BASSOULLET et al., 1983; MU, 1991, based on general morphology). Extant Halimeda species may show differences in the shape of the individual segments, and also segments from different parts of the plant may show vari- able numbers of utricle layers (e.g. DRAGASTAN et al., 2002). When referring these observations to fossil taxa, their correct determinations and descriptions become problematic. For instance, FLÜGEL (1975) remarked that differences in sizes of the thalli or siphons are not convenient for further splitting off the species Boueina hochstetteri TOULA. In fact, as has been pointed out by DRAGASTAN et al. (2002) the description of some fossil taxa are based on poorly, sometimes even insuffi cient material. As an exception to this, the thor- ough morphological study of the Turonian Halimeda elliotti by CONRAD & RIOULT (1977) differing between individ- ual-sized segments within one taxon should be highlighted. As a consequence, DRAGASTAN et al. (2002) synonymized a large number of the fossil “taxa” with recent representatives of Halimeda. Also, the genera Arabicodium ELLIOTT, 1957 and Boueina TOULA, 1884 were included within this Halim- eda concept and considered synonyms to Halimeda. As a consequence, all four representatives reported from the Trias- sic (B. hochstetteri liassica, B. marondei, H. helladica, H. dis creta, see introduction) were put in synonymy with Halim- eda cylindracea DECAISNE. This Halimeda concept of DRAGASTAN et al. (2002) only deals with a reduced number of methusalemi species exhibiting extremely long strati- graphic ranges, e.g. about 220 million years for Halimeda cylindracea. Despite the aforementioned problems with fossil taxa, such a rigid taxonomic reconsideration is at least prob- lematic without restudying the original materials, especially the biometric variabilities of the topo-type material, and addi- tional abundant and well-preserved material. As a consequ- ence of these problems concerning fossil material, HILLIS (2000, p. 189) concludes that “it seems prudent to maintain the status quo of the taxa (remark: Halimeda, Boueina, Arabi- codium)” for the moment being, as usually used by many workers (e.g. BUCUR, 1994). Another point to mention is that in some cases a radical synonymization obscures certain im portant biostratigraphic occurrences (e.g. BUCUR, 1999, tab. 17), for instance in the Upper Triassic-Liassic period. Therefore, and also due to the fact that our material is strongly recrystallized, not allowing observation of some morphologi- cal details, descriptions here use open nomenclature as Halim- eda? sp. 1 and Halimeda? sp. 2. We agree with many other workers, that the structural differentiation of Halimeda, Bou - eina and Arabicodium is too artifi cial and non-specifi c for a clear-cut separation of the three. Thus, the open nomenclatural approach refers to the genus Halimeda having priority as des - cribed the earliest of the three. Referring to only two thin- sections for each species, with some segments in low abun- dance, statistical analysis of the morphometric parameters cannot be provided. Moreover, detailed dimensions with res - pect to the individual sizes of different siphon orders are not appropiate due to the comparably poor state of preservation, instead only the size ranges of the meduallar (dms) and corti- cal siphons (dcs) are indicated. Outer segment diameters are indicated as D. Fi gu re 2: Halimeda? sp. 1. a) Longitudinal section. b) Longitudinal-oblique section. c) Two fragments. Sample WPA 233–97, scale bars = 2 mm. Geologia Croatica Geologia Croatica 61/2–3 132 Family Halimedaceae LINK, 1832 Genus Halimeda LAMOUROUX, 1812 Halimeda? sp. 1 (Fig. 2a–c) Description: Thallus segments cylindrical, uncompressed, showing slightly undulating diameters. The poorly calcifi ed medulla amounts about 1/3 of the segment diameter. There are no remarkable differences between the diameters of the me dul- lary and fi rst order cortical siphons. Higher order cortical siph- ons (up to 3–?4 series) become succesively reduced in their diameter. The cortical siphons continuously bend away from the axis. Dimensions: D = 1.8–2.35 mm; dms = 0.038–0.067 mm; dcs = 0.02–0.05 mm. Remarks: Halimeda? sp. 1 is distinguished from Hali- meda? sp. 2 especially by the medullar zone composed of more loosely packed siphons not signifi cantly different in diameter from the cortical siphons. Given that the fi ne medul- lary siphons are comparable to and not signifi cantly different from the cortical siphons, this taxon indicates an Arabicodium- type halimedacean alga if separation of the three different genera is accepted (see remarks above). Halimeda? sp. 2 (Fig. 3a–g) Description: Elongated-cylindrical segments (length up to 8 mm) showing constrictions at irregular distances (Fig. 3e). Cross-sections of segments are round. Medullar zone making up 28–45 % of the total segment diameter, broad with numer- ous close-set fi laments, irregularly disposed. The medullar zone may be well calcifi ed (Fig. 3a, f–g) but in other speci- mens appears as a sparitic central hollow (e.g. Fig. 3b, c). Spar-fi lled, interwoven medullar siphons are distinctly thicker than the cortical siphons, close-set leaving little intersiphonal space. Each medullar siphon is surrounded by a thin micritic wall (Fig. 3f–g). Dimensions: D = 0.65–2.6 mm; dms = 0.06–0.15 mm; dcs = 0.03–0.05 mm Remarks: Halimeda? sp. 2 resembles Halimeda hella- dica DRAGASTAN, KUBE & RICHTER, 2000, from the Rhaetian of Greece, later put in synonymy with Halimeda cylindracea by DRAGASTAN et al. (2002). Halimeda? sp. 2 is clearly separated from Halimeda? sp. 1 above all by the coarser and closer packed medularry siphons. Fi gu re 3: Halimeda? sp. 2. a) Transverse section (below) and oblique transverse section of Griphoporella curvata (GÜMBEL) (above). b) Two segments in oblique transverse sections. c) Oblique section. d) Longitudinal-oblique section. e) Longitudinal section showing segment constrictions. f ) Fragmentary longitudinal section showing coarse and close-packed medullary siphons. g) Fragmentary oblique section. Sample WPA 61–98, scale bars = 1 mm. Geologia CroaticaFelix Schlagintweit and Wolfgang Pavlik: New fi ndings of halimedacean algae from the Late Triassic Dachstein Limestone... 133 ACKNOWLEDGEMENT We sincerely thank Olga (Budapest) for the determination of the dasycladales, the Vienna Waterworks and the Federal Ministry for Science and Research for their fi nancial support of the karst-hydro- logic project. Helpful comments provided by reviewers Ioan BUCUR (Cluj-Napoca) and Ovidiu DRAGASTAN (Bucharest) are kindly acknowledged. REFERENCES BARATTOLO, F., DE CASTRO, P. & PARENTE, M. (1993): Some re- marks on Griphoporella curvata (Gümbel 1872) Pia 1915, dasycla- dacean green alga from the Upper Triassic. – Boll. Soc. Paleont. Ital., Spec. Vol. 1, 23–45. BASSOULLET, J.-P., BERNIER, P., DELOFFRE, R., GÉNOT, P., PON- CET, J. & ROUX, A. (1983): Les algues Udoteacées du Paléozoi- que au Cénozoique. – Bull. Centres Rech. Explor. –Prod. Elf-Aqui- taine, 7/2, 449–621. BUCUR, I.I. (1994): Lower Cretaceous Halimedaceae and Gymnoco- diaceae from Southern Carpathians and Apuseni Mountains (Ro- mania) and the systematic position of the Gymnocodiaceae. – Bei- tr. Paläontol., 19, 13–37. BUCUR, I.I. (1999): Stratigraphic signifi cance of some skeletal algae (Dasycladales, Caulerpales) of the Phanerozoic. – Palaeoplagos, Spec. Pub. 2, 53–104. CONRAD, M. & RIOULT, M. (1977): Halimeda elliotti nov. sp., algue calcaire (Chlorophyceae) du Turonien des Alpes-Maritimes (S.E. France). – Géol. Méditer., 4/2, 83–96. DRAGASTAN, O., KUBE, B. & RICHTER, D.K. (2000): New Late Triassic calcareous algae from Hydra, Greece. – Acta Palaeont. Ro- maniae, 2 (1999), 139–156. DRAGASTAN O., LITTLER, D. S. & LITTLER, M. M. (2002): Recent vs. fossil Halimeda species of Angaur Island, Palau and adjacent western Pacifi c areas. – Acta Palaeont. Romaniae, Spec. Pub. 1, 3–20. ELLIOTT, G.F. (1957): New calcareous algae from the Arabian penin- sula. – Micropaleontology, 3/3, 227–230. ELLIOTT, G.F. (1991): Dasycladalean Algae of the Palaeozoic and Mes- ozoic. – In: RIDING, R. (ed.): Calcareous Algae and Stromatolites. Springer, Berlin, 125–130. FLÜGEL, E. (1975): Kalkalgen aus Riffkomplexen der alpin-mediter- ranen Obertrias. – Verhandl. Geol. B.-A., 1974/2–3, 297–346. FLÜGEL, E. (1988): Halimeda: paleontological record and palaeoenvi- ronmental signifi cance. – Coral Reefs, 6 (1988), 123–130. HILLIS, L.W. (1991): Recent calcifi ed Halimedacea. – In: RIDING, R. (ed.): Calcareous Algae and Stromatolites. Springer, Berlin, 167– 188. HILLIS, L.W. (2000): Phylogeny of Halimeda (Bryopsidales): Linking palaeontological, morphological and molecular data. – Acta Palae- ont. Romaniae, 2 (1999), 183–189. JOHNSON, J.H. (1964): The Jurassic Algae. – Quart. Colorado School of Mines, 59/2, 1–129. LAMOUROUX, J. (1812): Classifi cation des Polypiers coralligènes on entièrement pierreux. – Nouv. Bull. Soc. Philom, 3, 181–188. LEIN, R. (2000): Die Hallstätter Trias der Mürztaler Alpen. – Mitt. Ges. Geol. Bergbaustud. Österr., 41, 289–296. MU, X. (1991): Fossil Udoteaceae and Gymnocodiaceae. – In: RIDING, R. (ed.): Calcareous Algae and Stromatolites. Springer, Berlin, 146– 166. OTT, E. (1967): Dasycladaceen (Kalkalgen) aus der nordalpinen Ober- trias. – Mitteilungen der Bayerischen Staatssammlung für Paläon- tologie und Historische Geologie, 7, 205–226. PIA, J. von (1920): Die Siphoneae verticillatae vom Karbon bis zur Krei- de. – Abh. zool.-bot. Ges. Wien, 11/2, 1–259. SENOWBARI-DARYAN, B. & HAMADANI, A. (1999): Girvanella coated udoteacean oncoids from the Upper Triassic (Norian-Rha- etian) Nayband Formation, south of Abadeh (central Iran). – Rev. Paléobiol., 18/2, 597–606. SENOWBARI-DARYAN, B. & ZAMPARELLI, V. (2005): Triassic Hali- medaceans: New genera and species from the Alps, Sicily and South- ern Apennines. – Rev. Espan. Micropaleont., 37/1, 141–169. SPENGLER, E. (1920): Zur Stratigraphie und Tektonik der Hochschw- abgruppe. – Verh. Geol. St.-A., 1920, 49–60. TOULA, F. (1884): Geologische Untersuchungen im westlichen Theile des Balkan und in den angrenzenden Gebieten. (X) Von Pernik nach Sofi a, auf den Vitos, über Pernik nach Trn und über Stol nach Pi- rot.- Sitzungsber. – K. Akad. Wiss. Wien, 88/3-5, 1279–1348. Manuscript received February 18, 2008 Revised manuscript accepted May 19, 2008