Paleobiota of the Posidonia Shale

The Posidonia Shale or Posidonienschiefer Formation is a geological formation of southwestern Germany, northern Switzerland, northwestern Austria, southeast Luxembourg and the Netherlands, that spans about 3 million years during the Early Jurassic period (early Toarcian stage). It is known for its detailed fossils, especially sea fauna, listed below. Composed mostly by black shale, the formation is a Lagerstätte, where fossils show exceptional preservation (Including exquisite soft tissues), with a thickness that varies from about 1 m to about 40 m on the Rhine level, being on the main quarry at Holzmaden between 5 and 14 m. Some of the preserved material has been transformed into fossil hydrocarbon Jet, specially wood remains, used for jewelry. The exceptional preservation seen on the Posidonia Shale has been studied since the late 1800s, finding that a cocktail of chemical and environmental factors let to such an impressive conservation of the marine fauna. The most common theory is the changes on the oxygen level, where the different anoxic events of the Toarcian left oxygen-depleted bottom waters, with the biota dying and falling to the bottom without any predator able to eat the dead bodies.
Dinoflagellata.
Dinoflagellate cysts.
The evolutionary burst of the Toarcian Dinoflajellates led the first appearance and rapid radiation of the Phallocystaceae ("Susainium", "Parvocysta", "Phallocysta", "Moesiodinium" and related forms). This occurred at the time of a wide-spread Lower Toarcian bituminous anoxia-derived shale of the "Posidonienschiefer Formation". Is recovered on the Posidonienschiefer, Pozzale, Italy, Asturias, Spain, Bornholm, Denmark, the Lusitanian Basin of Portugal, the Jet Rock Formation in Yorkshire and to the "Schistes Carton" in northern France. Whether there is a causal connection in this co-occurrence of Phallocystaceae and bituminous facies is a problem still to be resolved. This family has its acme in diversity and quantity in the latest Toarcian and became less important in the Aalenian.
Algae.
Includes abundant variety of algae, such as the genus of colonial Green algae Botryococcus, or the unicellular algal bodies Tasmanites, and other small examples. Algae are a good reference for changes on the oxygen conditions along the Toarcian.
Fungi.
Fungal Spores, hypae and undeterminated remains are a rare element of the otherwise openmarine deposits of the Posidonienschiefer formation, but where recovered at Dormettingen. This fungal remains are composed mostly by indeterminate spores and indicate oxygenated environments and suitable transportation by rivers. 
Plantae.
The macroflora of the Posidonia slate can be described as extremely poor in species. Apart from the remains of Horsetails, it is without exception the remains of coarse branches and fronds from gymnosperms, in which one has a certain can assume transport resistance. Remains of Ferns are completely missing, except for tall arboreal ferns (Peltaspermales). Mostly of the flora was reported from the area of Braunschweig. The major explanation for the flora could be that the plants in question are mono-or oligotypic stands on the edge of the waters that flow into the Posidonienschiefer sea, probably tear away in the course of flood events, easily fragmented during transport and wave waves, possibly especially in the occasional storm events postulated. In terms of taphonomy, this would result in a comparison with today's reed Phragmites, which can form extensive stocks on the edge of shallower and slowly flowing waters ("Reed belts"). The Wood remnants clearly indicate one higher diversity of Coniferous flora in the delivery area than the remains of leafy branches. This fact is likely to be proportionate, similar to that frequent occurrence of charcoalized or gagged trunks, mostly of them are believed to be "driftwoods" that only take a long time drifting also suggests a frequent settlement with mussels and full-grown Sea Lilies. The deposition settings are at large distance from the nearest coastline (for southern Germany about 100 kilometers), making only plants strong to transportation able to resist enougth to get deposited. At Irlbach and Kheleim, NE of Regensburg, where the Posidonienschiefer has it´s nearmainland deposit with abundant sand, a rich desposit filled with plant remains of different kind (Seds, Reproductive organs, Leafs, Stems, Cuticles and wood) with traces of coal was recovered, hovewer, it was never studied in depth. Of all the plant material expected only a few Bennetites leafs and two conifer branches with leaves where cited and none studied.
At the Austrian realm The sachrang Member was developed in the basinal area, while the Unken Member, sandwiched between red, often condensed limestones, represents the marginal facies. Due to be more marginal and connected with the southern Vindelician land, the most diverse palynological assamblages of the formation are found, transported from zonas with moldanuvian granites as proven by the feldespar accumulations.
Phytoclasts.
Phytoclasts have been recovered from several sections on the formation, but only studied in depth from the Dotternhausen and specially Dormettingen. Here two kinds of Phytoclasts where recovered, opaque phytoclasts (charcoal, indicator of wildfire activity on nearby landmasses, indicator of seasonal alterations of the water column) and translucent phytoclasts (indicator of proximal landmasses with high aviability of wood and other plant material, as well transport conditions). On the lowermost part of the section opaque phytoclasts are low (15% of the total organic matter) while tranlucent are incredibily abundant (40%), lowering it´s abundance to a 20-10% on the next section. The Exaratum Subzone is the only one with an inverse trend and more abundance of opaque phytoclasts. On the Bifrons level, both types reach between a 15% and a 30%, showing a rapid increase, to decrease on the end of the section to values of less than a 10%. Opaque Phytoclasts, for a supposed marine deposit are relatively abundant on some sections, whose decreasing on others suggest (along with increasing levels of Kaolinite) an increased delivery of land plant material by rivers, from areas with wetter climate and less frequent fires, while its rise suggest the opposite, nearby continental setting with dry climate and continuous wildfire activity.
Fossil wood.
Fossil Wood increases on the marginal Unken Member, with great amounts of logs and fragments of more than 1 m. Surface studies suggest relationships with the wood genera identified on the coeval Úrkút Manganese Ore Formation.
Ichnofossils.
The major ichnological analyses of the Posidonian Shale come from Dotternhausen/Dormettingen, where the ichnogenus "Phymatoderma" formed the so called Tafelfleins and Seegrasschiefer. The Tafelflein bed was deposited under anoxic bottom and pore water, where a recover of oxygen allow the Phymatoderma-producers return. The two organic-rich layers (Tafelfleins and Seegrasschiefer) are characterized by the dense occurrence of trace fossils such as "Chondrites" and "Phymatoderma", done episodically due to the fall of the oxygen levels. The Coeval more nearshore Swiss deposits referred Posidonian Shale (Rietheim Member) hosted similar trace fossils asthose recovered on SW Germany. Tougth this setting apparently evolved faster to more oxic-to-dysoxic bottom waters.
At Unken, laminated deposits of red limestone suggest well oxygenated active waters (as lack shale), where high amounts of "Chondrites" are found.
Invertebrata.
Porifera.
In the non-bituminous facies located on Obereggenen im Breisgau (Shore of the Black Forest High), especially the lower semicelatum subzone, pyritized individual needles of silica sponges (Demospongiae and Hexactinellida) are found, rarely on pelagic layers to very often on the low depth marine deposits. They are usually associated with radiolarian stone cores. In Dusslingen and Reutlingen, these sponge needles could be barytized in phosphorites of the Haskerense subzone and are much more common here than in any other zone of the Lower Toarcian. These needles are absent in the bituminous horizons of the entire Lower Toarcian. 
Increased amounts of Sponge needles (dominated by Hexactinellida) are also found on the arenaceous facies of the nearshore unit that is the Unken member, being the only section if it´s region that hosts them, probably due to be an active and well oxygenated bottom. The location of this member as a possible bay on the south of the vindelician land probably allow to the development of more pre-Toarcian AOE conditions, hence the presence of biota otherwise rare on bituminous layers.
Arthropoda.
Insecta.
Insects are a common terrestrial animals that were probably washed into the sea due to monsoon conditions present on the Posidonia Shale.
Echinodermata.
Echinoderm debris is pretty abundant on the shale-free Unken and Salzburg members, including Crinoid skeleton elements, also that of the Ophiurida; the Echinoids take their place, where really blossomed at that time. That´s why Pedicellaria are observed very often.
Vertebrata.
Amniota.
Ichthyosauria.
Inderminate specimens are known.
Saurischia.
Possible teeth from Dinosaurs are known from the Lias Clay pit of Unterstürmig (Referred as "Various Archosaur teeth"). "Dinosaur Fossils" are cited to be present on several levels on Schandelah.