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A Fossilized Microcenosis in Triassic Amber. Schönborn, W., Dörfelt, H., Foissner, W., Krienitz, L

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A Fossilized Microcenosis in Triassic Amber. Schönborn, W., Dörfelt, H., Foissner, W., Krienitz, L J:' Eu.l@ryot. Microbiol., 46(6), 1999 pp. 57 l-584 @ 1999 by the Society of Protozoologists l A Fossilized Microcenosis in Triassic Amber WILFRIED SCTTÖNNONN," HEINIRICH DÖRtr'ELT,O WILHELM FOISSNER," LOTIIAR KRIEMTZd ANd URSULA SCHAF'ER" "Friedrich-schiller-[Jniversität Jeru, Institut fiir ökologie, Arbeitsgruppe Limnologie, Winzerlaer Strafie 10, D-07745 Jena, Germany, and bFriedrich-Schiller-tlniversität Jena,Institut fiir Ernährung und (Jmwelt, Ichrgebiet Landschaftsökologie und Naturschutz, Dornburgerstrat3e 159, D-07743 Jena, Germany, and "Unbersität Salaburg, Institut für Zoologie, HellbrunnerstraJ3e 34, A-5020 Salzburg, Austria, and dlnstitutfür Gewässerökologie und Binnenfischerei, Alte Fischerhütte 2, D-16775 Neuglobsow, Germany ABSTRACT. Detailed data on bacterial and protistan microfossils axe presented from a 0.003 mm3 piece of Ttiassic amber (Schlier- seerit, Upper Tliassic period, 22O-23O million years old). This microcenosis, which actually existed as such within a very small, probably semiaquatic habitat, included the remains of about two bacteria species, four fungi (Palaeodikaryomyces bauerL Pithornyces-like conidia, capillitium-Iike hyphae, yeast cells) two euglenoids, two chlamydomonas (Chlamydomonas sp., Chloromonas sp.), two coccal green microalgae (Chlorell.a sp., Choricystis-like cells), one zooflagellate, three testate amoebae (Centropyxis aculeata var. oblonga-like, Cyclopyxis eurystoma-like, Hyalosphenia baueri n. sp.), seven ciliates (Pseudoplatyophrya nana-l|ke, Mykophagophrys terricola-like, Cyrtolophosis mucicola-like, Paracondylostoma sp., Bryornetopus triquetrus-like, Tetrahytnena rostrata-Ike, Pararnecium triassicurn n. sp.) The microfossils correspond to or diverge from extant species only slightly. Key Words. Evolutionary comments, fossilized bacteria, ciliates, flagellates, fungi, green algae, testaceans, preservation, Schlierseerit. THE "Schlierseerit", amber which comes from layers of An amber piece containing microfossils was placed in the I Raibler Sandstone of the "Leitnernase" near the village chamber, covered with a cover glass, and sealed by phytohistol of Schliersee (Bavaria, Germany), has been investigated inten- (Carl Roth GmbH & Co., Karlsruhe, Germany). sively for 10 years by many scientists. This amber dates from A Zeiss-Microscop Axioplan equipped with differential in- the Upper Triassic period (Carnian stage of Keuper) and may terference contrast and a throughlight-stereoscopic picture mi- be 22O-23O million years old. Its flnder, U. Ch. Bauer, discov- croscope Axiolab (up to 1000X enlargement without restriction ered the amber as small pieces of ( 1 mm to max. 20 mm. A of resolution) were used to observe the inclusions tridimen- surlmary of all flndings concerning this amber has been com- sionally. piled by Vavra (1996; see also Nicke1 1995). Using carbon-I3- nuclear magnetic resonance spectra, the resin source is probably RESULTS a coniferous plant of the Araucari aceae (Lambert, Johnson, and Fungi (Fig. I-7)' Poinar 1996), already known from the Palaeozoic period. The Many fungal rerlnants were included in the amber between preliminary investigation on this amber was carried out by remains of plants, bacteria, and protists. Five types of fungi Poinar, Waggoner, and Bauer (I99a; see also Bauer 1993) who were regularly observed: described bacteria, fungi, algae, testaceans, and ciliates. Since there are only scant flndings of freshwater (or terrestrial) pro- 1. Pqlaeodikaryomryces baueri-like Dörfe1t, already described tists from early geological periods, the above-mentioned are the d Schäfer 1998), could be earliest known soft-bodied forms. The present paper describes newly confirmed. It is a saprophytic fungus with non-septate in more detail a microcenosis of an amber fragment with a hyphae and vesiculi, developing septae, branches at the ves- volume of only 0.003 mm3, and cornments on evolutionary and iculi, great clamps or loops, a+d cysts at the loops (Fig. L, ecological consequences of these discoveries. 2,3). 2. A saprophytic fungus with septate hyphae and oogonia-like METHODS cysts, possibly a stage from Palaeodikaryomyces baueri-like (Fig. 4) or an as yet undescribed saprophytic fungus. The size of the pieces of Schlierseerit exploited in the present Thick-walled, capillitium-like hyphae with papillary orna- paper ranges from nearly 100 pm to some rnm. Since the mi- 3. ments and occasionally with blastoconidia (Fig. 5), probably crofossils are situated tridimensionally in the amber, simple mi- an as yet undescribed species. croscopic observation and taking micrographs is difflcult; usu- 4. Remnants from a saprophytic fungus, which may be a yeast ally the distance between object and lens is too large. Sections' cbll of a dimorphic fungus or a separated visicle from Pa- are impossible because many inclusions would be destroyeä. laeodicaryomryces baueri, germinating with small hyphae Breaking it into smaller pieces is the best method because fhe (Fig. 6). inclusions remain undamaged and are eventually set free from 5. Pithom)tces-Llke conidia, dark brown, muriform (Fig. 7), the amber. may be macrocenidia belonging to the capillitium-like hy- Tiny or broken amber pieces were at flrst investigated in phae described above. water, photographed, and after air drying, treated with a neutral mixture of paraffin oil and alkylaromates (Chemisches Labor Bacteria (Fig. 8, 9) CarI Zeiss, Oberkochen, Germany); the density (L.525) of this We found many fllamentous and single bacterial structures mixture is similar to that of the Schlierseerit. The oil penetrates (Fig. 8, 9), but it is impossible to identify them without chem- the amber and microfossils, especially fungal hyphae, and ical analysis. clears the structures, but only in the fi.r-st 30-60 min, which is the most favorable time for microscopic investigations. After Algae (Fig. 10-17) 60 min the oil dissolves the amber and''destroys the pieces. Euglenoids. Two specimens of euglenoid flagellates were For preservation, small chambers ("sarcophages") "were found in the Triassic amber. One cell body was spirally twisted, burned with the help of CO, laser in glass microscope slides. indicating the typical metabolic character of Euglena cells (Fig. 10). The ceIl was approximately 25 p"m long (unfortunately, the Corresponding Author: W. Schönborn-Telephone number: 00491 apical part was covered and hence not clearly visible), width 036411651 591 ; FAX number: 0049/036411657 600; Email: varied between 2:6 lrm. The cell had a short caudal spine. limnolo g @ r z.uni -j ena. de Inside the cell, different granulated and refractile structures 571 572 J. E,UKARYOT. MICROBIOL., VOL. 46, NO" 6, NOVEMBER*DE,CE,MBtr,R 1999 ,' d, --->L\" Li 1 b _*-> a -*+ <-a ,*_ b trig. l-2. Palaeodikaryomyces baueri. a, clamps or loops; b, cysts, growing from the clamps; d, vesicles. 2 Fig. 1, bar 5 pm; 2, bar 20 pm. were visible, possibly chromatophores, pararnylon grains, vac- sembling extant Chlorella species (FiS. 12, 16), and slightly uoles, and reddish carotene*containing oil droplets. The other ellipsoidal cells resembling extant Choricysris-like cells because cell, about 50 x 12 1tm in size, exhibited a fusiform shape (trig. they contained trough-like parietal chloroplasts. The cells at the 1 1). lower region of the size spectrum (< 3 pm) were identif,ed as Monadal chlorophytes. There were two types of ovoidal "picopLankton" (Fig. 15, L7). chlorophytes in the amber. The thick-waltred cells clearly indi- cate the character of monodal algae, although flagella were Zoaflagellates (Fig. 18-20) missing. The cells were oval in longitudinal view, and spherical About ten inclusions resembled longish cells with a thread- in the apical view. The f,rst type of cells (trig. 11) had a size like elongation on one end, very likely a flagellum. The length of 4-6 X 8-10 pm. It contained a cup-shape chloroplast ranged from 9"6-13.0 prn (including flagellum). Zoochlorellae 'These equipped with a pyrenoid in the basal part. cells can be were not visible, so these inclusions were very likely heterotro- identified as the genus Chlamydomonas. The second type of phic flagellates" cells had a size of about 15-18 X 28-32 p.m. The inner side of the cell wall was covered by a chloroplast, which did not Testate Arnoebae (Fig. 2L-27) contain a pyrenoid. In the central part of the cells several vac- uoles were visible. A reddish-colored, stigrna-like structure was Three testacean species could be identif,ed" fbund near the apical region in some cells. These cells are com- 1. Hyalosphenia baueri n. sp. (Fig. 2L, 22) parable with extant species of the chlamydophycean genus Chloromonas (trig. 1 1-15). I)iagnosis. Shell about 60.0 X 95.5 Fffi, indistinctly vase- Chlorococcal picoplankton" Wide areas of amber were shaped, with two opposite lateral pores, mernbraneous, struc- fllled with minute spherical structures. In most cases, these tureless, brown, compressed, with a small collar around the ap- might be artifacts. However, some specimens showed the char- erture, which is terminal and (probably) oval. acter of algal cells, containing chloroplasts and vacuoles. We Type location. Tiiassic amber from Mount Leitnernase near classified these small structures, with a size af 2-5 X 3-6 Fffi, the village of Schliersee (Bavaria, Germany). in two different morphotypes: more or less spherical cells re- Type material. Flolotype (Fig. 22) SCHÖNBORN E,T AL.-F'OSSTLIZF.,D MICROCE,NOSIS IN TRIASSIC AMBER 513 a --r> , ,:i a -_> 3 ' :r,1,.ri.a.T§;§§E5bT'1:1:-'l';i" .li.i+.. - rr'r'. a 4 ir'' 5 b 7 t''S' b --> a ---> rdd,{Y&!'ii'' "i r'"' ' "..'P.' Fig. 3-7. Palaeodikaryomyces baueri, and other fungal remnants.3. Palaeodikaryomyces baueri, hyphae; a, clamps or loops; c, rounded apiculus of the hyphae; d, vesicles. 4. Oogonia-like structure (a) of a saprophytic fungus. 5. Thick-walled capillitium-like hyphae ofa saprophytic fungus (a, diameter of hyphae; b, blastoconidium). 6. Hypha-body or separated vesicie (a), germinating with smaller hyphae (b). 7. Conidium, darkbrown and muriform. Fig.3,4,5,6, bars 20 pm;7, bar l0 pm. Etymology. Named in honour of U. Ch. Bauer, the finder of 2.
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