Recent freshwater oscillatoriacean analogue of the Lower Palaeozoic calcareous alga Angulocellularia

Recent freshwater cyanophyte oncoids from Canandaigua Lake, New York, consist almost entirely of minute irregular, bush-like, micritic masses comparable with the calcareous alga Angulocellularia Vologdin from Lower Cambrian algal-arehaeocyathan bioherms and biostromes of the Siberian Platform and western Mongolia. The Recent specimens arc radially orientated within the oncoids and occasionally contain moulds of axial filaments 15 μm in diameter. Acid-residues of the oncoids yield abundant Schizothrix calcicola. The micritic bush-like masses are interpreted to have formed by the calcification of the sheaths of these cyanophytes. This analogue allows Angulocellularia to be reinterpreted as a calcified oscillatoriacean cyanophyte, rather than a rhodophyte as previously suggested. It indicates that filamentous cyanophytes can produce apparently solid calcareous fossils, not only porostromatc tubes. The occurrence of Angulocellularia has been overlooked in some previous studies of Cambrian and Ordovician bioherms. The generic diagnosis is emended.     

Devonian carbonate buildup facies in an intra-oceanic island arc (Tamworth Belt, New South-Wales, Australia)

Summary  Biohermal and biostromal buildups were investigated in late Early and Middle Devonian carbonate complexes of the Tamworth Belt. The buildup types and subtypes were studied in three regions (Yarramanbully, Sulcor and, Wyaralong') to clarify their paleo-environmental position. Two stages of development are recognized: Incipient bioherms and bioherms. Incipient bioherms are carbonate buildups with organisms which commonly form true bioherms. They dominate the sediment with small growth forms but are not prolific enough to build large bio-frameworks. Small nodular and globular stromatoporoids characterize the incipient bioherms and are interpreted as stunted growth forms. In one location (‘Wyaralong’) the coarse stromatoporoid calcarenite represents a fore-reef facies, at Sulcor a shallow subtidal setting with moderate water energy can be deduced. The bioherms can be sub-divided into stromatoporoid-, stromatoporoid-Stachyodes-, and stromatoporoid-rugose coral bioherms. Their variable composition probably reflects growth and deposition in different zones of a reef complex and/or different proximity to areas of denundation indicated by high siliciclastic input. In the Tamworth region true bioherms occur only in the Moore Creek Limestone Member (Middle Devonian), and not in older carbonate successions. Biostromes are sub-divided into (1) incipient biostromes with stromatoporoid-heliolitid biostromes and alveolitid biostromes; (2) aggregate biostromes withAmphipora andStachyodes biostromes; (3) stratified biostromes; (4) mixed aggregate/stratified biostromes. The different types of biostromes are not limited to specific time-intervals, but rather to environmental conditions.

Late Paleozoic reef mounds of the Carnic Alps (Austria/Italy)

The Late Paleozoic (early Kasimovian-late Artinskian) sedimentary sequence of the Carnic Alps (Austria/Italy) is composed of cyclic, shallow-marine, mixed siliciclastic-carbonate sedimentary rocks. It contains different types of skeletal mounds in different stratigraphic levels. The oldest mounds occur at the base of the Auernig Group, within a transgressive sequence of the basal Meledis Formation. These mounds are small and built by auloporid corals. Algal mounds are developed in the Auernig Formation of the Auernig Group, forming biostromes, and Lower Pseudoschwagerina Limestone of the Rattendorf Group forming biostromes and bioherms. The dominant mound-forming organism of these mounds is the dasycladacean alga Anthracoporella spectabilis. In mounds of the Auernig Formation subordinately the ancestral corallinacean alga Archaeolithophyllum missouriense is present, whereas in mounds of the Lower Pseudoschwagerina Limestone a few calcisponges and phylloid algae occur locally at the base and on top of some Anthracoporella mounds. Mounds of the Auernig Formation formed during relative sea level highstands whereas mounds of the Lower Pseudoschwagerina Limestone formed during transgression. The depositional environment was in the shallow marine, low-turbulence photic zone, just below the active wave base and lacking siliciclastic influx. The algal mounds of the Carnic Alps differ significantly from all other algal mounds in composition, structure, zonation and diagenesis; the formation of the mounds cannot be explained by the model proposed by Wilson (1975). The largest mounds occur in the Trogkofel Limestone, they are composed of Tubiphytes/Archaeolithoporella boundstone, which shows some similarities to the “Tubiphytes thickets” of stage 2 of the massive Capitan reef complex of the Guadalupe Mountains of New Mexico/West Texas.     

Taphonomic differentiation of Oxfordian ammonites from the Cracow Upland, Poland

Taphonomic analysis of Lower and Middle Oxfordian ammonites from the Cracow Upland, southern Poland (localities at Pod???e, Zalas, M?ynka) revealed differences in ammonite preservation. The studied ammonites, usually termed as external and internal moulds, show a more complex state of preservation. In the Middle Oxfordian glauconitic marls, ammonites are preserved as internal moulds with neomorphic calcite shells showing relics of the original internal structure. In the Middle Oxfordian platy peloidal limestones, ammonites are preserved mostly as external moulds, without septal suture, however under microscope might show relics of internal whorls and septa and/or subtle differences in sediment filling phragmocone chambers. In sponge–microbial bioherms and biostromes, ammonite internal moulds have shells, which in contrast to ammonites from glauconitic marls are not strictly neomorphic ones, but originated by shell dissolution and subsequent filling of moldic porosity by calcite cement. In sponge–microbial nodular limestones, the ammonites are strongly deformed and the outer wall is usually removed by dissolution under pressure. Other important taphonomic differences include the rate of compaction (highest in platy limestones), sedimentary infillings, microborings, encrustations and preservation of siphuncular tubes. The majority of the ammonites appear to be phragmocones; aptychi in all facies are rare. Siphuncular tubes are fossilized exclusively in oppeliids, only in specimens from glauconitic marls and platy limestones, although their other taphonomic attributes are different. Tubes seem to have fossilized due to microbially mediated phosphatization that could be favoured by a set of parameters which operated rather at the scale of ammonoid carcasses: closed, poorly oxygenated conditions, and reduced pH. Taphonomic processes were controlled by the sedimentary environment (fragmentation, sedimentary filling, phosphatization of siphuncular tubes), as well as by early and late diagenesis (neomorphic transformation, dissolution, cementation, compaction) influenced by lithology.     

Lower Ordovician sponge bioherms in the Makkol Formation, Taebaeksan Basin, mideast Korea

Summary Isolated sponge bioherms are documented from the Lower Ordovician Makkol Formation of the Taebaek Group in the Taebaeksan Basin, mideast Korea. They are formed by an association of a lithistid spongeArchaeoscyphia, a receptaculidCalathium and stromatolitic algae, and share many features with the Lower Ordovician buildups known elsewhere. These bioherms were established in an incised bottom and reached up to about 1 m in height. As the bioherms grew upward, they were more severely affected by intense wave action and frequent storms, which eventually perished the bioherms. The occurrence ofArchaeoscyphia-Calathium association suggests a close biogeographic link between Korea and North China, supporting the paleogeographic model that the Taebaeksan Basin was connected through contiguous shallow waters to North China in the early Paleozoic.     

Sequence stratigraphy and paleo-oceanography of an open-marine mixed carbonate/siliciclastic succession (Late Jurassic,Southern Germany)

Summary The Late Jurassic epicontinental sea of South Germany protruded far to the North forming a wide bay which was rimmed by shallow-water platforms (Swiss and French Jura). This wide shelf is characterized by extensive downslope mud accumulations including siliceous sponge buildups. The bioherms are aligned along the more pericontinental parts of this shelf, which graded to the South into the Helvetic Basin of the Tethys Ocean. Five sedimentary cycles of Oxfordian to Middle Kimmeridgian age (ox. 2–ox. 3, ki.1.–ki.1.2, ki.3, ki.1.3–ki.2.1, ki. 2.1–ki. 2.2) were used for interregional correlation. Each cycle is characterized by a vertical suite from marl to pure limestone. The bases of the marls are characterized by abundant open-marine fossils, glauconite and phosphate (fish teeth and pellets) and interpreted as condensed sections. Deepening is indicated by bioherms changing their growth form before demise from large structures into small isolated buildups, which commonly occur within deeper water. Sequence boundaries, are present at the transition from marl into limestone. Two phases (middle ki. 1.3 and ki. 1/2) of debris-flow deposition, one accompanied by the sudden spreadout of biostromes and basinward shift of bioherms, are interpreted as lowstand phases associated with sequence boundaries. The remaining sedimentary cycles described here lack such lowstand deposits. Instead, corresponding positions in the cycles are characterized by omission features. This problem is still unresolved. It may either be due to sediment trapping on the ramp or to a changing origin of the cycles compared. It is proposed here that highstand sediments, having higher contents of fine-grained siliciclastics than lowstand deposits, formed during a humid and warm climate with high rates of continued runoff and sediment transport. Lowstand deposits consist of pure offbank carbonates, because the associated drier climate reduced fluvial input of terrigenous material. Corresponding patterns of climatic change are also seen in platform sediments from the Swiss Jura Range; however, climatic cycles correlate with eustatic sea level fluctuations in only about 50% of the cases. This misfit may partially result from problems with biostratigraphic correlation (boreal— Tethyan). Small-scale sedimentary cycles with an average duration of 66’000 years (Mutabilis chron, ki. 2) to 95’000 years (Planula chron, ox. 3) provide a tool for detailed stratigraphic correlation in biostromes, small scale lenticular bioherms (1–2 m thickness) and large bedded bioherms (many tens of metres thickness). Interruptions of bioherm growth are due to temporal oxygen deficiency related to plankton blooms. The bathymetrically deepest bioherms-small and lenticular in shape—therefore suffered the highest number of ecological break-downs, whereas massive bioherms continuously remained above the critical level.     

Sclerite-bearing alveolitid favositids from the Devonian of central Poland

Calcitic and pyritic pseudomorphs of originally siliceous monaxonic sclerites (predominantly heloclone-like monocrepid desmas) have been found entrapped within calcareous skeletons of alveolitid favositids identified as Squameoalveolites fornicatus (SchlÜter 1889) derived from Lower and Middle Devonian (Emsian and Eifelian) deposits of central Poland. The sclerites are arranged in a system of subvertical tracts forming a loose palisade along the midwall of skeletal tubes. Poorly preserved remnants of such palisades correspond to the so-called »median line« or »median suture« of typical favositids. The finding supports the hypothesis of poriferan affinity of favositid Tabulata and indicates that these common Palaeozoic fossils cannot be longer classified as Cnidaria. They should, on the basis of the sclerites, be regarded as remnants of monaxial and/or sublithistid demosponges, which - like the members of modern and fossil demosponges called sclerosponges or coralline sponges - had the ability to produce a basally secreted calcareous skeleton in addition to siliceous sclerites.     

Lower Cretaceous (Albian) shell-armoured and associated echinoid trace fossils from the Sácaras Formation, Serra Gelada area, southeast Spain

The Sácaras Formation (Albian, Lower Cretaceous) of the Serra Gelada succession (Prebetic of Alicante), southeast Spain, comprises carbonate‐rich, upwards thickening parasequences in which many types of trace fossils have been identified. The present study focuses on two types of tubular trace fossil characterized by features of their external coating. The first type is represented by a shell‐covered, structured trace fossil, up to 4?cm in diameter and 40?cm in length, built horizontally, from rectilinear (type 1) to gently curved (type 2), which envelopes an unstructured pipe of grey silty sediment. The coating is characterized by imbricated, flat particles, mainly orbitolinid foraminifers and other planar bioclasts, forming thin concentric layers; in cross section the bioclasts produce a typical plumed structure. This trace fossil represents a new ichnogenus and ichnospecies, here named Ereipichnus geladensis. Particle arrangement of the external coating is similar to that of terebelloid tubes, but Ereipichnus is a horizontal trace fossil, whereas structured worm tubes are vertical. The second type is a grain‐coated trace fossil, tubular in shape, with a simple internal structure. The coating is often reddish with respect to the neighbouring dark grey sediment and shows a slightly coarser‐grained texture, which envelopes the internal muddy pipe. This type, which yielded echinoids, was produced by irregular or heart‐shaped sea‐urchins (spatangoids) and is attributed to Scolicia or Cardioichnus. Facies analysis of the Serra Gelada succession with Ereipichnus and Scolicia or Cardioichnus locally shows other types of branched trace fossils (primarily represented by different forms of Thalassinoides) and bioturbation is developed in tiers, increasing upwards in abundance and diversity.     

Evidence for a fungal affinity for Nematasketum,a close ally of Prototaxites

As part of a project investigating diversity in early terrestrial vegetation, new specimens of the enigmatic, non‐embryophyte Nematasketum diversiforme have been described from Lower Devonian strata in the Welsh Borderland to elucidate its affinities and role in the ecosystem. Charcoalified fragments were investigated using scanning electron microscopy. They show for the first time that at least part of the organism possessed an axial organization with a peripheral zone forming a rind. The specimens differ from the closely‐allied Prototaxites by the presence of unevenly thickened tubes, both in well‐defined areas (medullary spots), hypothesized as being the sites of hyphal generation, and in the matrix of wide, smooth‐walled and narrow hyphae. Two specimens that show branching but no unequivocal thickened tubes are best assigned to the prototaxalean complex. The fragments, with longitudinally aligned wide tubes in a matrix of much branched, narrower examples, resemble rhizomorphs and cords of extant basidiomycote fungi and are interpreted as exploratory and translocating organs. Postulated affinities of Prototaxites include algae, fungi and hepatics, with the latter interpreting the fossils as rolled‐up liverwort mats. Our studies on a close ally of Prototaxites show no evidence for hepatic affinity, although similarities with fungal linear mycelial structures. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 1–18.     

The ecology of Cenomanian lithistid sponge frameworks, Regensburg area, Germany

Upper Jurassic‐Lower Cretaceous sponge biostromes and bafflestone mounds were common and widespread in European temperate to tropical marine environments. They declined markedly during the Late Cretaceous. Most sponge frameworks were paucispecific and ecologically simple, with only basic levels of succession or tiering. The occurrence of ecologically complex, lithistid sponge biostromes and mounds in the Cenomanian Quadersandstein Member, Regensburger Grünsandstein of the Saal Quarry, Bavaria, is therefore of special significance. These are ecologically the most complex sponge frameworks yet reported from the Cretaceous. Their size, morphology and ecological organization compare favorably with shallow‐water, sponge‐dominated frameworks in modern seas. The Saal Quarry sponge frameworks are generally associated with firmgrounds and condensed intervals in the transgressive systems tract of the Cenomanian‐Turonian, tectonoeustatic supercycle UZA‐2. The lowest sponge frameworks are up to 1 m high bafflestone mounds consisting of large, irregular, sheet‐ and mound‐like recumbent sponges overlain by diverse, cylindrical, pyriform, upward‐branching forms of Jerea and Siphonia. These biostromes overlie a condensed interval or firmground which locally contains small, in situ pyriform sponges (Jerea pyriformis Lamouroux) as well as Middle Cenomanian Inoceramus etheridgei Woods. The upper sponge frameworks consist of bafflestone mounds up to 4.4 m wide and 1.3 m high, composed of six lithistid sponge morphotypes, possibly representing several species of Jerea and Siphonia. The occurrence of Rotalipora cushmanni in strata overlying the upper sponge framework indicates a Late Cenomanian age. Morphotypes preserve internal sponge morphologies and partially dissolved spicules surrounded by a diagenetic halo of silicified, pelletoid grainstone and/or packstone. Silica cements were derived from spicule dissolution. Different combinations of these morphotypes dominate three to four successional stages of sponge framework growth, and show vertical ecological tiering within communities. This ecological zonation is consistent among frameworks, and is partially or wholly repeated between storm‐related disturbance events.     

陕南新元古代末期微体管状疑难化石

末元古纪以Cloudina为代表的管状动物化石是目前世界上公认最早的具矿化骨骼的生物类群,在世界许多地区都有发现,但它并不是当时唯一的矿化生物类型,更多的动物骨骼化化石证据在寒武纪大爆发之前的沉积物中时有发现。作者在处理陕南末元古纪的化石过程中,发现了大量不同形态的微体管状化石(直径大多小于150μm),包括末端封闭的粗短管体,不分枝管体,末端扩展的骨针状构造及具多种分叉样式的分枝管体。这些化石的亲缘关系仍不清楚,但它们为我们提供了动物演化和矿化初始阶段的化石记录。     

Paleoecology of Upper Eifelian and Lower Givetian coral limestones in the northwestern Sauerland (Devonian; Rhenish Massif)

Summary The prevailing sandy/silty lower part of the Middle Devonian in the northwestern Sauerland includes two coral limestone horizons, which contain a rich fauna of corals, stromatoporoids, and calcareous algae. The Ihmert-Formation is subdvided into three parts. The older coral limestone horizon is the Grünewiese-Member of the Ihmert-Formation (uppermost Eifelian), the younger is in the Bredenbruch-Member of the Unterhonsel-Formation (lower Lower Givetian). Conclusions about the environmental constraints are drawn from the sedimentology and the fossil content of the coral limestones. Predominant biostromes are built between storm wave base and normal wave base. Only the few bioherms grew above the normal wave base. These coral limestones were deposited in a tropical or subtropical normal marine environment in the shallow euphotic zone. Among the reef-builders epoecism is very frequent, and until now this phenomenon has not been investigated in detail. Fragile rugose and tabulate corals lived as commensals with stromatoporoids. Some other aspects of paleoecology are concisely presented.     

Palaeontological and sedimentological effects of micro‐bioherms in the Middle Silurian Massie Formation of southeastern Indiana,USA

Small build‐ups composed primarily of micrite and benthic skeletal remains, termed ‘micro‐bioherms’, have been recognized within Silurian strata of eastern and midcontinental United States for well over 75 years; however, previous research has focused nearly entirely on such structures within the upper Wenlock (Homerian) Waldron Shale. An undolomitized section of the lower Wenlock (Sheinwoodian) Massie Formation in Ripley County, southeastern Indiana, was studied to assess the influence of micro‐bioherms on palaeoecological, taphonomical and sedimentological patterns. Increased baffling of fine‐grained material by organisms composing and/or encrusting build‐ups is evidenced by muddy sediment containing pascichnial traces surrounding micro‐bioherms. Pelmatozoan attachment structures densely encrust micro‐bioherms, but are swollen by secondary stereomic overgrowths reflecting some form of antagonistic interaction or investment in strong affixation to elevated substrates. Clusters of bumastine trilobite material occur in ‘pockets’ related to cavities within build‐ups, and otherwise rare spathacalymenid trilobites, often exceptionally preserved, are found in muds in the vicinity of partially buried micro‐bioherms. Coeval sections nearby are nearly unfossiliferous as result of dolomitization, but contain recognizable skeletal material in greatest abundance in micro‐bioherm flank beds. The occurrence of these bodies within the Massie Formation is genetically linked to a major transgressive episode, but also reflects a mid‐Silurian climatic/palaeoceanographic change.     

Reefal and mud mound facies development in the Lower Devonian La Vid Group at the Colle outcrops (León province, Cantabrian Zone, NW Spain)

In the locality of Colle (Cantabrian Zone, NW Spain), the upper part of the Valporquero Shale Formation (Emsian, La Vid Group) contains an interval of shales and marlstones (barren, greenish-grey shales and fossiliferous, greenish-grey or reddish shales/marlstones) with beds and packages of homogeneous and cross-bedded skeletal limestones. Metre-scale mud mounds and coral biostromes occur encased in the fossiliferous reddish and greenish-grey shale/marlstones, respectively, with the coral biostromes overlying conspicuous skeletal limestone bodies. These rocks were deposited on a carbonate ramp, ranging from above storm wave base for the cross-bedded skeletal limestones to below the storm wave base for the remaining deposits, organic buildups included. The vertical stacking of these facies and the occurrence of the two types of buildups are interpreted to reflect the interplay among several (possibly 4th and 5th) orders of relative sea-level variations, during a 3rd-order highstand. Coral biostromes occur in early 5th-order transgressive system tracts developed within late 4th-order highstand, and are interpreted to have thrived on a stable granular substrate (skeletal limestones) in non-turbid waters, being later aborted by the onset of muddy sedimentation. Biostrome features suggest that they developed under environmental conditions essentially different from those related to the sedimentation of their granular substrate. Mud mounds occur in 5th-order transgressive and early highstand system tracts tied to early 4th-order sea-level rise. Field relationships suggest that mud mounds grew coevally with muddy sedimentation, with high-frequency variations in carbonate vs. terrigenous mud sedimentation influencing their development.An erratum to this article can be found at     

Remarkably preserved annelid worms from the La Meseta Formation (Eocene), Seymour Island, Antarctica

Abstract: Worm tubes, which exhibit the replaced tube-lining membrane, have been collected from the lowermost Lower Eocene Acantilados Allomember of the La Meseta Formation, Seymour Island, Antarctica. The discovery represents the oldest examples of preservation of the tube-lining membrane of tube-dwelling Polychaeta in the fossil record. A new genus and species, Caprascolex antarcticus , are described. The specimens are preserved as thin coatings of amorphous iron oxide on the inner surface of the moulds interpreted to be the replaced tube-lining membrane. Examination of the rarely described tube-lining mucosoid membrane in extant polychaetes shows that the fossils are nearly identical in morphology and scale to extant forms. These fossils record in remarkable detail the morphology of the tube-lining membrane, which appears to be composed of growth bands formed as the worm constructed the tube. The tube-lining is believed to have been originally preserved as pyrite, with subsequent oxidation to iron oxide. The tube-lining membrane of worm tubes possibly is known from only one other fossil occurrence.     

Morphology and affinities of an Early Cretaceous Ephedra (Ephedraceae) from China

Detailed investigations on Lower Cretaceous Ephedra L. fossils (Gnetopsida) reveal morphological characters similar to those of extant Ephedra rhytidosperma Pachomova, including articulate branches with many fine longitudinal striations, a dichasial branching pattern, uni- or bi-ovulate cones with paired bracts, cones terminal on branchlets, and seeds with a short, straight micropylar tubes, covered by numerous regular and prominent transverse laminar protuberances. Fossils are similar to extant E. rhytidosperma reproductive organs but differ in some vegetative structures and are described and discussed here as Ephedra archaeorhytidosperma Y. Yang et al. Because E. rhytidosperma is currently considered one of the most specialized members in Ephedra L. section Pseudobaccatae Stapf, the occurrence of E. archaeorhytidosperma in the Yixian Formation suggests that Ephedra L. was perhaps a more diverse genus in the Lower Cretaceous. Perhaps the evolution and diversity of Ephedra L. was already in place by the Lower Cretaceous and certainly before the end of the Mesozoic.     

云南永善肖滩剖面早寒武世Lapworthella (托莫特壳类)骨片化石

描述了采自云南永善肖滩剖面下寒武统石岩头组的托莫特壳类(tommotiids)骨片化石Lnpworthella rete Yue,1987,其骨片锥状或塔状,横向环脊明显,环脊尖棱状;骨片外表面具多边形网状纹饰,但无齿、瘤或纵脊等装饰;骨片可分为两种类型,即弯曲型和近直立型,前者数量明显多于后者。简要地讨论了托莫特壳类化石的分类及生物亲缘关系,认为目前为止,其仍为亲缘关系不明的化石类别。尚难断定所有的托莫特壳类骨片化石皆属于同一生物门类,因为难以证明将它们归人同类生物所依据的骨片性状是共同衍征(synapomorphy)还是由于趋同演化(convergent evolution)的结果;在缺乏躯干化石记录的情况下,离散骨片的生物亲缘关系研究较为困难。     

Late Triassic reefs from the Northwest and South Tethys: distribution, setting, and biotic composition

The paleolatitudinal distribution patterns during Ladinian and Carnian time are characterized by an increasing expansion of reefs from the northern to the southern hemisphere. The optimum of reef diversity and frequency in the Norian is associated with the development of extended attached or isolated carbonate platforms. Norian-Rhaetian sponge and coral reefs of the Northern Calcareous Alps developed (1) as reef belt composed of patch reefs in platform-edge positions facing the open-marine northwestern Tethys basins and (2) as patch reefs in intraplatform basins as well as in ramp positions.Carnian and Norian-Rhaetian sponge and coral reefs of the Arabian Peninsula are formed (1) as reef complexes at the margins of carbonate platforms on the tops of volcanic seamounts in the southern Tethyan ocean, as small biostromes on these isolated platforms, and (2) as transgressive reef complexes on the attached platform of the Gondwana margin. The Norian Gosaukamm reefal breccia of the NW Tethys is a counterpart of Jabal Wasa reefal limestone of the Gondwana margin with similarities in geological setting and biotic composition. Rhaetian coral biostromes of low diversity known from the Austrian Koessen basin resemble to the time equivalent Ala biostromes of the isolated Kawr platform in the southern Neo-Tethys by forming a discontinuous layer in shallow intraplatform basin setting.     

An atypical fauna in the Lower Devonian Hunsrück Slate of Germany

The Hunsrück Slate is a world renowned conservation lagerstätte, stretching SW-NE in a narrow band between the villages of Bundenbach and Gemünden, Hunsrück region, Germany. A great variety of complete Lower Devonian fossils is preserved with their soft parts pyritised due to rapid burial by sediment. The fossils of the Hunsrück Slate outside the narrow band are scarcely known. They represent the normal Situation: quiet low energy Sedimentation. This paper describes this overall “Rhenish” neritic fauna under the heading “atypical”, in contrast to the famous fossils of the conservation lagerstätte. The fauna described here lacks starfishes, mitrates and chelicerates. The paper begins with an overview of the recent relevant literature (stratigraphic position of the Hunsrück Slate, palaeoecology). The slate fossils were collected in two quarries WNW and NE of Bundenbach (Lingenbach and Karschheck, respectively) and most closely resemble that of the Wisper Valley in the Taunus region. Their geologic age is Lower Devonian, early Emsian, Ulmen Substage. Special interest is given to Community structures, rugose corals, bivalves, gastropods, trilobites, conulariids, brachiopods and crinoids. In the systematic part, the crinoidOrthocrinus simplex is redescribed. Also, two new species are introduced: the rugose coralVolgerophyllum karschheckensis n. gen., n. sp., and the crinoidAcanthocrinus spinosus n. sp.