Tambach Formation

housed most of the Tambach Formation's most famous fossils. Starting in the 1840s, five-toed footprints had been described from various sandstone quarries and roadcuts in the Gotha district of Germany. The stratigraphy of rocks near Tambach-Dietharz was mapped out in 1876, and named as the "Tambacher Schichten" (Tambach strata) in 1895, although at the time it was believed to include several additional rock layers (now termed the Elgersberg and Eisenach Formations) which have since then been separated from it. in 1887 the first fossilized footprints from Bromacker were discovered by a local fossil collector named Heinrich Friedrich Schäfer. The find was donated to the Ducal Museum in the city of Gotha, after which it was independently reported on by various German paleontologists who had received photographic evidence. Wilhelm Pabst, the curator of the Ducal Museum's natural history department, collected and described 140 sandstone slabs from the Tambach Formation from 1890 until his death in 1908. The collection was rediscovered in the 1950s, and subsequently restudied by GDR paleontologists such as Hermann Schmidt, Arno Hermann Müller, and Hartmut Haubold. Fossilized tetrapod bones were discovered in the upper beds of Bromacker by Thomas Martens in 1974, prompting further attention from Gotha paleontologists. These include Harald Lutzner, who formally delineated the Tambach Formation as a sequence including two conglomerate layers separated by a sandstone layer. In the coming years, research contacts were made with Western paleontologists such as Jürgen Boy (University of Mainz) and David Berman (Carnegie Museum of Natural History). This allowed excavation to ramp up and the Tambach Formation to achieve worldwide fame. A 1993 German-American joint expedition recovered articulated tetrapod fossils, and trace fossil collecting was resumed after more than 80 years thanks to the excavation of a new sandstone quarry at Bromacker in 1995. The first Tambach body fossils outside of Bromacker were discovered in 2008, in a construction site in downtown Tambach-Dietharz. In 2010, the exhibits comprising Gotha's Museum of Nature began the process of being moved from the Ducal Museum (which was being converted to an art museum) to the Friedenstein Castle. Due to funding issues, collecting from Bromacker has been limited and the Tambach collection is being archived at the historic Perthesforum complex prior to the construction of a new Permian exhibit. == Geology ==

The Tambach Formation mainly lies within a basin currently occupied by the Thuringian Forest, and it is stratigraphically younger than the Rotterode Formation and older than the Eisenach Formation. It is the oldest part of the Thuringian Forest Basin's Upper Rotliegend succession, a name referring to a sequence of purely sedimentary rocks in the Lower Permian of Germany. The sediments of the Tambach Formation were deposited in a small Permian graben (termed the Tambach Basin), which was oriented in a northeast to southwest direction and incised into the igneous and sedimentary rocks of the Rotterode Formation. The Tambach Basin would have about 250 square km during the Permian, though modern outcrops only occupy about 50 square km, not counting the northeastern portion of the basin which has had its deposits erased by later geological processes. a cluster of small abandoned quarries near the town of Tambach-Dietharz. Strata exposed to the surface at Bromacker corresponds to the center of the Tambach Basin, during the time of the upper portion of stage I and the lower portion of stage II. Stage I sediments at Bromacker are termed the "lower beds" However, it is unclear whether the strata at Elgersburg are younger, older, or equivalent in age to the Tambach Formation. and late Artinskian Lioestheria monticula/andreevi biozones, respectively. The only species of tetrapod known to exist in both the Tambach Formation and North American faunas is Seymouria sanjuanensis, which persisted for approximately 15 million years between the Asselian and the early Kungurian. Since the species of Dimetrodon present at Tambach is smaller than those present in the red beds of Texas, the Tambach Formation was likely older than those formations. The Tambach Formation was placed within the Seymouran LVF (Land Vertebrate Faunachron) of Lucas (2006), a biozone which was estimated to include the Artinskian-Kungurian boundary. Combining both invertebrate and tetrapod biostratigraphy, the age of the Tambach Formation was considered to be probably Artinskian in age. This estimate is based primarily on the radiometric age of 295.8 ± 0.4 Ma (late Asselian) of the Rotterode Formation which unconformably underlies the Tambach Formation, and on the estimate that the interval of geologic time not represented between the two formations is less than 2 million years. In addition, comparison of the footprint assemblage of the Tambach Formation with radiometrically dated Permian footprint assemblages from France and Italy also suggests a Sakmarian age. == Climate ==

in present-day South America, which may have had a similar climate to the Tambach Formation. The sand and silt-rich portions of the Tambach Formation were likely deposited in a warm climate with both hot, dry parts of the year and periodic heavy rainfall events. The dry times were severe enough to evaporate the Tambach basin's flood-induced ephemeral lakes within a matter of days, restricting the ability of a permanent aquatic fauna to colonize the basin. However, most plant root fossils are horizontally (rather than vertically) oriented, indicating that the climate was generally humid enough that native plants would not need to evolve deep roots or other xerophytic adaptations. Because of this, the Tambach Formation would probably fall under the modern tropical savanna climate, despite its lack of grass. Modern climatic equivalents include the northern African savanna and the Llanos of Venezuela and Colombia. There is evidence that sub-zero temperatures may have occurred on some nights during the dry season, likely as a result of the basin's high elevation. The climate may have been drier during the conglomerate-rich periods of the Tambach Formation. ==Paleobiota==

The ecosystem of the Tambach Formation is unusual for its lack of aquatic animals such as xenacanthid sharks, Eryops, or Diplocaulus, which are otherwise common in Early Permian red beds. This is best explained by its mountainous environment, isolated from the monsoonal lowland floodplains which deposited most of the red beds. In addition, the ephemeral nature of the Tambach Basin's lakes and rivers means that only aquatic animals adapted to such conditions, such as conchostracans, were able to flourish. The Tambach Basin did support a diverse amphibian fauna, but only terrestrially-adapted types including dissorophoids and seymouriamorphs. Large herbivorous tetrapods such as caseids and especially diadectids are the most common body fossils recovered from the formation, while carnivorous synapsids are relatively rare. This is in contrast to North American environments, where fossils of carnivores such as Dimetrodon outnumber herbivore fossils. The environmental conditions of Tambach likely created a food web which was very different from that of the lowlands. The most common plants were tough, drought-adapted types such as conifers, while seed ferns and other lowland plants were much rarer. Fibrous terrestrial plants encouraged colonization of the basin by herbivorous land animals, but the dry climate prevents the development of an aquatic food chain, inhibiting animals such as large species of Dimetrodon, which get a large portion of their food from waterways. The Tambach Formation preserves the oldest known terrestrial regurgitalite (fossilized vomit), in the form of a cluster of bones including material from Thuringothyris, Eudibamus, and diadectids. The regurgitalite was probably from a large predator such as Dimetrodon teutonis or Tambacarnifex. Flora Invertebrates Basal Tetrapods Reptiles Synapsids Tetrapoda indet. == References ==