Lower Permian terrestrial paleoenvironments and vertebrate paleoecology ofthe Tambach basin (Thuringia, Central Germany): The upland Holy Grail

The Bromacker section of the Lower Permian, Tambach Formation, in central G ermany, yields an important fossil-vertebrate assemblage that was deposited in an upland setting near the center of a small, internally-drained paleog raben. The fossil-vertebrate assemblage shares many taxa in common with oth ers that are well-documented from North America., but is atypical in the: ( 1) unusually large abundance of the terrestrial herbivore Diadectes; (2) co mplete absence of aquatic and semi-aquatic vertebrates; and (3) rarity of m edium-to-large carnivorous synapsids. The graben. setting and the low-diver sity, terrestrial, fossil-vertebrate assemblage together comprise a unique upland paleoecosystem, heretofore undocumented in the Early Permian. The co mposition of and relative abundances within the assemblage at Bromacker sug gest that experiments with "high-fiber" vertebrate herbivores as the domina nt or significant basal component of vertebrate food webs had begun by the Early Permian, but only in settings with few or no aquatic and semi-aquatic vertebrates. The combined stratigraphic section at Bromacker consists of portions of two conformable stratigraphic intervals-the Lower and the Upper beds. Depositi onal events in both were dominated by seasonal-to-subseasonal cycles of flo oding in an ephemeral, alluvial-to-lacustrine setting that was hot year-rou nd with annual precipitation similar to that of a wet-and-dry tropical or w etter climate. Excellently preserved, articulated and disarticulated fossil vertebrates indicate subaerial exposure times of short duration and limite d reworking. In the case of articulated specimens, death and burial were pr obably coeval events, most likely caused by floods.