Dictyodoru and associated trace fossils from the Palaeozoic of Thuringia MICHAEL J. BENTON Bcnton. Michael J. I9X20701: Oicfyodoru and aswciated trace fo$sils from the Palacomic of Thuringia LJETWAIALethuia, Vol. 15, pp. 115-132. Oslo. ISSN 00?4-1164. Dicryudora occurs in the Huupryuurrif (Late Ordovician; D. rimmermunni) and Bordenschiefer (Early Carboniferous; D.liebruna) olThuringia, East Germany. It is ahscnt in the Early Dcvonian Nc're~tenyuur- zfr, and analysis of the trace fosd assemblages points to environmental partitioning within thc 'deep-sea' Nererres Aswciation. The Carhoniferous Dicryodora was much larger than thc Early Palacomic forms and had a long respiratory (7)wall organ. This may have hccn an adaptation to feeding dceper in anoxic sediments, and thc animal devclopcd large 'parapodia' to ctfcct its progression through the sediment. 0 Truce fussib, Pulueozoic,. Nercites Associufion. Thuringiu, Dictyodora. hlichuel J. Benlon. Nurure Conserruncy Council, Pew1 House, Burrhoiomew Sfreer, Newbury, Berkshire, RGl4 5LS. Englund, U.K.;13th May, 1981 (rrrsisrd 198-70119). The Thuringian Schiefergebirge, in the southern Permo-Triassic Thuringian basin, and to the DDR and partly in the BRD, consists of a series south by a similar large basin in southeastern of Proterozoic to Carboniferous metasediments, Thuringia and northern Franconia. During the only some of which are fossiliferous. Large tracts Palaeozoic, Thuringia lay on the southern margin yield only deep-sea trace fossil faunas of Late of Baltica, or Laurussia, which allowed continu- Ordovician, Early Devonian, and Early Carbon- ous marine sedimentation until mid-Carbonifer- iferous age. Dictyodoru occurs in the Ordovician ous times when the central European plate at- and Carboniferous deposits, but is absent from tached (Ziegler et al. 1979). the Devonian. The stratigraphy of Thuringia is reviewed in During a recent trip to East Germany, I was Hoppe & Seidel (1973), and the main features, able to visit several localities and collect trace and the trace fossil-bearing beds, are surnrnarised fossils (because of the politically sensitive nature in Fig. 3. The Early Ordovician Phycoden-Serie of some of the localities, I would like to make it is a shallow water deposit with trace fossils clear that I visited the sites as a holiday-maker (Hundt 1941b) typical of the Cruziunu Facies and did so without the advice or assistance of (Seilacher 1978), and it will not be considered anyone living in the DDR). The aim of this work further here. Rare Dictvodora, Nereites and is to offer new information on the evolution and Neonereites have been reported from the Late biology of Dictyodora, and to review relevant Devonian near Saalfeld (Fig. 1; Richter & Unger features of the associated ichnofaunas. 1856; Pfeiffer 1951), but the main trace fossil horizons of interest here are the Late Ordovician Hauptquarzit, the Early Devonian Nereitenquar- zit, and the Early Carboniferous Bordenschiefer. Geological setting The Lower Palaeozoic rocks of the Thuringian Schiefergebirge (Fig. 1) are exposed in two Trace fossils of the Late Ordovician SW-NE trending horsts, the Schwarzburger Sat- tel (including the Grbfenthuler Horst) in the west, Hauptquarzit and the Lobensteiner Horst (passing north into The Hauptquarzit is dated as ?Llandeilo-Cara- the Bergaer Sattel) in the east. These structural doc on the basis of the faunas of adjacent beds highs were formed during the Variscan orogeny, (Kniipfer 1967:69; Wiefel 1974: 185-186), and it and they are separated by a large area of Early is exposed only in the eastern horst. Between Carboniferous (Culm) sediments. The Palaeo- Zeulenroda and Hohenleuben (Fig. 3A), this zoic rocks are bounded to the north by the large unit is about 170 m thick, and reaches its thickest 116 Michael J. Benton LETHAIA 15 (1982) Fig. I. Map of the Thuringian Schiefergebrrge showing main Palacozoic outcrop. Major towns are named, and the horder between East and West Germany (DDK, BRD) is indicated. The western Schwarzburger Saltel runs SW from Saalfeld, and the eastern Berguer Satre/ runs SW from Wcida. Main trace fossil localitics arc indlcated with black triangles: 1. Wiinschendorf (Uppcr Ordovician). 2. Schaderthal (Lower Devonian), 3. Wurzbach (Lower Carhoniferous). Map modified from Deuber & Martini (1942), in Hoppe & Scidcl (1974). extent of 240 m at Wunschendorf. Two large and Lossau, near Schleiz (Zimmermann 189251; quarries here on the Hiittchenberg, just south of Fig. 3A herein). the town, expose a considerable part of the The trace fossils have been named as Dictyo- Hauptquarzit, which is strongly folded, jointed, dora zimmermanni Hundt 1913, Paleodictyon ei- and mineralised in part of the northern quarry. seleanum Hundt 1913, Arenicolites didyma Salter Body fossils are rare, and consist of an Ortho- 1857, A. obliquiforans Hundt 1928, A. simplex ceras (Bachmann 1954) and some inarticulate Hundt 1928, A. pfeifferi Hundt 1928, A. pas- brachiopods (Freyberg 1923:250). The Haupt- choldi Hundt 1931, Phyllodocites geraensis quarzit was interpreted by Kniipfer (1967:72) as Hundt 1928, and Arthrophycus flabelliforrnls a shallow water deposit, and Wiefel (1974:189) Hundt 1940. Hundt’s descriptions are poor, the wrote that it has ‘numerous features of shallow last eight names are inappropriate, and most of water and in places of submarine slumping’. Un- the traces have never been figured adequately. fortunately, there has been no detailed sediment- ological study, and a definite conclusion as to the environment cannot be reached. Fig. 2. Diagrammatic summary of Palaeozoic (Ordovician-Car- Trace fossils occur in maroon and grey-green boniferous) stratigraphy of the Thuringian Schiefergebirge in the Schwarzburger Sattel and the Bergaer Sattel. The main mottled parallel- and cross-laminated siltstones lithological types and average relative thicknesses of the units and mudstones in the quarries at Wiinschendorf in each horst are shown. Trace fossil horizons are marked on (Hundt 1912, 1928). Other localities include hill- the stratigraphic columns, and the pictographs on the right- side sites and quarries on the road between Ho- hand side show main components of the ichnofaunas. Dating from graptolites (Ordovician-Silurian), ostracodes and tentacu- henolsen and Hoehnleuben, Reichenfels ruined litids (Devonian). Based on information in Volk (1964b), castle, near Triebes (Hundt 1928, 1931a, 1941a), Pfeiffer (1968). Hoppe & Seidel (1974). and original data. LETHAIA 15 (1982) DICTYODORAand associated trace fossils 117 Trace fossils Oberkulm t MMddll) LOWER CARBONIFEROUS Unterkulm (BORDENSCHIEFER) Il-VI Upper I DEVONIAN SCHWXRZSCHIEFER TENTACULITENSCHICHTEN Lower (INCL. NEREITENQUARTZIT) SILURIAN LEDERSCHIEFER Grafenthal-Serie EISENERZ GRIFFELSCHIEFEF PHYCODENQUARZIT ORDOVICIAN 3 Phycoden-Serie 9grichnem v :hondrites k PHYCODENSCHIEFER Daedalus @ Jictyodora @ Diplocraterion Lophoctenium NeOnereiteS Nereites Paleodictyon @ Frauenbach-Serie Phycodes 4 Phycosiphon planolites a==9 .'X' protovirgularia / Scolicia &? Schwarzburger Bergaer scoyenia Sattel Sattel cf. SkolithoS 1 SANDSTONE/MUDSTONE Taenidium Tomaculurn %%&- LIMESTONE 118 Michael J. Benton LETHAIA 15 (1982) Fig. 3. Locality maps for trace fossil sites. 0 A Upper Ordovician Huuprquurzit of the Bergaer Suttel; approximate outcrop area shaded. 0 B. Lower Devonian Nereitenquurzii of the Schwarzburger Satref; approximate outcrop arca shaded. Lower Carbonifer- ous Untrrkulm of the Teuschnitz-Ziegenriick Mulde; outcrop east of the Devonian. Maps A and B include localities 1, and 2 and 3 of Fig. I, re5pectively. DICTYODOIUZIMMERMANNI Hundt 1913 4A) which probably represents a point at which Fig. 4A, B. the animal has changed level in the sediment. Dictyodora zimmermanni shows various pre- Synonymy. ~ 0 1892 Palueochorda; Zimnermann, p. 61. servational aspects, as in other examples of the 1912 Silur-Dicr.vodoru; Hundt, p. 93. 0 1912 Diqodoru lie- beuna (Geinitz): Aucrbach. pp. 127-128. * 1913 Dicryodora same genus (e.g. Pfeiffer 1959; Benton & Trewin zimmermunnc Hundt. pp. 180-181. 1928 Dictyodora zimmer- 1980). Most common are bedding plane views of manni Hundt; Hundt, pp. 27-31. 0 1928 Phyllodocrfes geraen- horizontal sections through the wall (Fig. 4A). sis Hundt, p. 32. 01929 Dictyodoru zimmermunni Hundt; Korn, pp. 26, 38. 0 1931a Dicfyodora zimmermunni Hundt; Bedding plane views of the basal burrow are Hundt, pp. 18+186. 0 1940 Arthrophycus flabelliformis rarer, probably because of the irregularly lami- Hundt, p. 211. 0 1941a Dictyodora zimmermanni Hundt; nated nature of the sediment.The vertical wall Hundt, pp. 150-151. represents a line of weakness through the sedi- Material. - Auerbach Collection, Hundt Collec- ment, and blocks may break in such a way as to tion, Natural History Museum, Gera (?). reveal side views of the wall (Fig. 4B), as in other material of Dictyodora (e.g. Weiss 1884b; Ben- Description. - The material from Wiinschendorf ton & Trewin 1980). The striation pattern is not displays the characteristic features of Dictyo- so well shown in the Hauptquarzit material be- dora: basal burrow and dorsal vertical wall. The cause of the relatively coarse nature of the sedi- basal burrow is preserved with a lenticular cross- ment, but there are clear oblique 'ripples' in the section and varies from 4 mm to 5 mm wide and wall, probably reflecting jerky progression up to 3 mm high. The wall is placed centrally on through the sediment. The basal burrow displays top of the burrow and is up to 25 mm high (Fig. 4