The Grünbach Formation is an Austrian geological formation that dates from the late Santonian to early Campanian age of the Late Cretaceous. It forms a part of the Gosau Group which was formed in a coastal freshwater/brackish to marine depositional environment. The Grünbach Formation is underlain by the marine carbonate Maiersdorf Formation and overlain by the marine siliciclastic Piesting Formation. The main lithologies are clay, marl, siltstone and sandstone, with a minor conglomerate component. Multible coal seams have also been noted. It is notable for its fossil diversity, including molluscs, reptiles and the Grünbach flora.
All mining operations in the Neue Welt area ceased in 1965, all later finds were made on the gobbins of the coal mines or historic collections.
The Grünbach Formation records a changing coastal landscape with shallow freshwater habitats, peat-forming swamps and marine incursions. Fossil plants suggest a mosaic of aquatic vegetation, Pandanites swamps, palm-rich wetland forests, riverside vegetation and other forests. Dense stands of Pandanites trinervis probably supplied much of the plant material that formed the coal.
Vertebrates Most remains have been found at a single locality, which is a thin marl seam in the Konstantin mining tunnel within the Felbering Mine, in the Neue Welt area, north west of Muthmannsdorf in Lower Austria. The initial remains were discovered in 1859, after an ornithopod tooth was found in a piece of coal in a dump outside the mine by Professor Ferdinand Stoliczka, and the productive seam discovered thereafter. The first material was described by Emanuel Bunzel in 1871 and then additional material was described by Harry Seeley in 1881.
Grünbach am Schneeberg is a less well known vertebrate fossil locality of the Grünbach Formation, which has gained some relevance due to newly described fossils. The first known finds were Kallokibotion shell fragments, additionally, lepisosteid teeth were first mentioned in 2025.
Fish Actinopterygii of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesLepisosteidae IndeterminateGrünbach am SchneebergTwo teeth and squamation Possibly an Atractosteus
Squamates Squamates of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesAraeosaurusA. gracilisMuthmannsdorfVertebraNomen dubium: Bunzel 1871: VI. fig. 11 (Der dritte, Taf. VI, Fig. 11)
Choristoderes Choristoderes of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesChoristoderaIndeterminateMuthmannsdorf"Two platycoelous vertebral centra"
Turtles Turtles of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesDortokidaeIndeterminateMuthmannsdorfShell fragmentscf. KallokibotioninaeIndeterminateMuthmannsdorf, Grünbach am SchneebergShell fragments
Crocodyliformes +Crocodyliformes of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesDoratodonD. carcharidensMuthmannsdorf"incomplete mandible, a fragmentary right maxilla, a parietal fragment, and isolated teeth"EusuchiaIndeterminateMuthmannsdorf"mandible fragment and some postcranial material"
Pterosaurs Pterosaurs of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesAzdarchidaeIndeterminateMuthmannsdorf"Proximal portion of a humerus"Previously referred to "O". buenzeliPterodactyloideaIndeterminateMuthmannsdorf"Articular region of a lower jaw, crushed phalangeal fragments"Previously referred to "O". buenzeli
Non-avian dinosaurs Dinosaurs of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesMochlodonM. suessiMuthmannsdorfCranial and postcranial elementsStruthiosaurusS. austriacusMuthmannsdorfCranial and postcranial elementsTetanuraeIndeterminateMuthmannsdorf"Two fragmentary teeth"Nomen dubium: ‘Megalosaurus pannoniensis’ Nearly identical to numerous teeth known from the Csehbánya Formation
Coprolites Vertebrate Coprolites of the Grünbach FormationGenusSpeciesLocationAbundanceNotesImagesCoprolitesIndeterminateMuthmannsdorf 20 specimens in six morphotypes; most indicate carnivorous to omnivorous diet with some herbivorous ones Contain arthropod parts, plant fragments, pollen, fungal spores, cyst-like structures and hyphae
Aquatic Invertebrates
Cnidaria Cnidarians of the Grünbach FormationGenusSpeciesLocationNotesImagesCunnolites Inhabited marine habitats
Gastropods Gastropods of the Grünbach FormationGenusSpeciesLocationNotesImagesActaeonella A. glandiformis Dreistätten—Feibering Cerithium C. münsteri Dreistätten—Feibering C. subgranatum Dreistätten—Feibering C. formosum Dreistätten—Feibering C. sociale Dreistätten—Feibering C. sexangulatum Dreistätten—Feibering Dijamira D. goldfussi Dreistätten—Feibering Fusus F. ex aff. tritonium Dreistätten—Feibering Omphalia O. kerfersteini Dreistätten—Feibering Pseudomelania P. turrita Dreistätten—Feibering Pyrgulifera Grünbach am Schneeberg Inhabited brackish habitats Rostellaria R. sp.Dreistätten—Feibering Tanalia T. acinosa Dreistätten—Feibering Trochactaeon T. gigantea Dreistätten—Feibering Inhabited brackish and marine habitats Turbo T. ex aff. spiniger Dreistätten—Feibering
Molluscs Molluscs of the Grünbach FormationGenusSpeciesLocationNotesImagesCucullaea Dreistätten—Feibering Sphaerium S. gregariaGrünbach am Schneeberg Formerly known as Cyclas gregaria; inhabited freshwater habitats Trochoceramus T. cf. morgana Identifies minimal age of Grünbach Formation T. cf. dobrovi Identifies minimal age of Grünbach Formation Unio U. cretaceousGrünbach am Schneeberg Inhabited freshwater habitats Polymesoda Inhabited brackish habitats
Terrestrial Invertebrates
Insects Insects of the Grünbach FormationGenusSpeciesLocationFossil TypeMaterialNotesImagesCoprolithesIndeterminateIchnofossilFecal pellets around 1mm in size Likely produced by Termites IchnotaxaIndeterminateGrünbach am Schneeberg IchnofossilLeaf fossil with insect feeding and egg-laying traces The egg-laying traces are endophytic and possibly stem from leaf-hoppers or damselflies. More traces like this are likely in Grünbach-Flora; more research is required.
Molluscs Molluscs of the Grünbach FormationGenusSpeciesLocationFossil TypeMaterialNotesImagesStrophostomellaS. reussiType localities: Neualm in Rußbach am Pass Gschütt, Starhemberg castle bei Piestig Additional localities: Grünbach am Schneeberg, MuthmannsdorfBody fossilsMulitble specimens from Grünbach am Schneeberg in NHM Vienna and Städtische Museum Neunkirchen Terrestrial snail, formerly known as Boysia reussi, which is based on a faulty description and drawing from Stoliczka, 1860
Grünbach Flora
Most of these specimens were found in Grünbach am Schneeberg in lower Austria. Most of these specimens were found in Grünbach am Schneeberg in Lower Austria, hence the name. Pteridophytes Pteridophytes of the Grünbach FormationGenusSpeciesLocationNotesImagesCladophlebisC. gosauensisGrünbach am Schneeberg, Muthmannsdorf Foliage of tree ferns, typical for a humid habitat Coniopterissp.Grünbach am Schneeberg Equisetitessp.Grünbach am Schneeberg A horsetailGosauopterisG. danaeoidesGrünbach am Schneeberg, Dreistätten, Muthmannsdorf, Frankenhof Probable affinities with MarattiaceaeMarsileaceaephyllumM. campanicumGrünbach am Schneeberg Marsileaceae, very similar to extant MarsileaMicrophyllopterisM. austriacaGrünbach am Schneeberg, Muthmannsdorf MonheimiaM. ungeriiGrünbach am Schneeberg, Muthmannsdorf Affinities with Matoniaceae, particularly PhanerosorusRaphaeliaR. lobifoliaGrünbach am Schneeberg, Höflein SphenopterisS. gruenbachianaGrünbach am Schneeberg Probable affinities with SchizaeaceaeS. heterophyllaMuthmannsdorf S. ungeriGrünbach am Schneeberg S. sp.Grünbach am Schneeberg
Gymnosperms Gymnosperms of the Grünbach FormationGenusSpeciesLocationNotesImagesGeinitziaG. formosaGrünbach am Schneeberg Pinopsida, Taxodioid affinity; inhabited riparian wetland forests G. reichenbachiiGrünbach am Schneeberg, Frankenhof Pinopsida, Taxodioid affinityLindleycladusL. lanceolatusGrünbach am Schneeberg NilsoniaN. cf. holyiGrünbach am Schneeberg Bennettitales; indicates a cooler climate Pagiophyllumsp.Grünbach am Schneeberg Part of upland vegetationPodozamitessp.Grünbach am SchneebergPart of upland vegetation
Angiosperms
Monocots Monocots of the Grünbach FormationGenusSpeciesLocationNotesImagesGruenbachiaG. pandanoidesGrünbach am Schneeberg, Muthmannsdorf Pandanaceae, reproductive organs of PandanitesLysichitonL. austriacusAraceae, genus extantOrontiophyllumaustriacumGrünbach am Schneeberg PandanitesP. trinervisGrünbach am Schneeberg, Dreistätten, Muthmannsdorf, Frankenhof Pandanaceae, main coal forming plant in Grünbach FormationSabalitesS. longirhachisGrünbach am Schneeberg, Muthmannsdorf, Felbering, Maiersdorf Palm; inhabited riparian wetland forests TheiaiphyllumT. kollmanniiGrünbach am Schneeberg
Dicots Dicots of the Grünbach FormationGenusSpeciesLocationNotesImagesBrasenitesB. krasseriiGrünbach am Schneeberg affinity with Brasenia; aquatic freshwater plant CelastrophyllumC. johannaeGrünbach am Schneeberg, Muthmannsdorf Hamamelidaesp.Grünbach am Schneeberg HamamelidaeCeratoxylonsp.Grünbach am Schneeberg Reproductive structureCompositiphyllumC. serratumGrünbach am Schneeberg DebeyaD. insignisGrünbach am Schneeberg DicotylophyllumD. proteoidesGrünbach am Schneeberg, Muthmannsdorf, Frankenhof D. sp.1, sp.2, sp.3, sp.4, sp.5, sp.6, sp.7Grünbach am Schneeberg EttingshauseniaE. gruenbachianaGrünbach am Schneeberg, Maiersdorf Platanaceae; characterizes meandering rivers E. cf. laevisGrünbach am Schneeberg E. sp.Grünbach am Schneeberg GrebenkiaG. europeicaGrünbach am Schneeberg cf. GrevilleophyllumG. constansNomen dubium.JuglandiphyllitesJ. pelagicusGrünbach am Schneeberg, Dreistätten, Muthmannsdorf possible affinity with Juglandaceae; characterizes meandering rivers and riparian wetland forests LeguminositesL. mucronataGrünbach am Schneeberg Part of upland vegetationMenispermitesM. ettingshauseniiGrünbach am Schneeberg M. summesbergeriiGrünbach am Schneeberg MyricophyllumM. serratumGrünbach am Schneeberg Affinities with MyricaM. cf. zenkeriGrünbach am Schneeberg Affinities with Myricacf. PandemophyllumIndeterminate, P. cf. proteoidesQuereuxiaQ. angulataGrünbach am Schneeberg Possible affinity with Trapa; aquatic freshwater plant Rogersiasp.Grünbach am Schneeberg TernstroemitesT. (?) neueweltensisGrünbach am Schneeberg ViburniphyllumV. austriacumGrünbach am Schneeberg V. ermanniiGrünbach am Schneeberg
Pollen and Spores
Bryophytes Bryophytes of the Grünbach FormationGenusSpeciesLocationNotesImages Stereisporites Indeterminate Representative of Sphagnaceae
Lycopodiophyta Lycopodiophytes of the Grünbach FormationGenusSpeciesLocationNotesImages Camarozonosporites Indeterminate Representative of Lycopodiaceae Retitriletes Indeterminate Representative of Lycopodium
Pteridophytes Pteridophytes of the Grünbach FormationGenusSpeciesLocationNotesImages Appendicisporites A. tricuspidatus Probable affinities with Schizaeaceae Cicatricosisporites Indeterminate Probable affinities with Schizaeaceae CingulatisporitesIndeterminateAffinities with AnemiaCyathiditesIndeterminateEchinatisporitesIndeterminateGleicheniiditesG. senonicusLeiotriletesIndeterminateRepresentative of LygodiumMatonisporitesIndeterminateFound in situ with MonheimiaMicrotaeniaM. austriacaPolypodiaceoisporitesIndeterminate
Gymnosperms Gymnosperms of the Grünbach FormationGenusSpeciesLocationNotesImagesPityosporitesIndeterminateTaxiodiaceaepollenitesIndeterminateAt least 2 taxa
Angiosperms
Monocots Monocots of the Grünbach FormationGenusSpeciesLocationNotesImages Arecipites Indeterminate Representative of Palmae SpinizonocolpitesIndeterminateRepresentative of extant Nypa palm
Dicots