# Erfurt Formation

The Erfurt Formation, also known as the Lower Keuper (German: Untere Keuper, Lettenkeuper, Lettenkohle or Lettenkohlenkeuper), is a stratigraphic formation of the Keuper group and the Germanic Trias supergroup. It was deposited during the Ladinian stage of the Triassic period. It lies above the Upper Muschelkalk and below the Middle Keuper.

## Definition

The formation was defined in Erfurt-Melchendorf in 1830 by Franz Xaver Hofmann and named for the nearby town of Erfurt.
The Erfurt Formation is underlain by the Upper Muschelkalk. The lower boundary to the Erfurt Formation is the "Lettenkohlensandstein" in northern Germany and the "Grenz-bone-beds" in southern Germany.
The formation is a sequence of dolomite, lacustrine limestones, claystone, evaporites, and fluviatile sandstones. The color is usually grey but can also be brown or reddish brown. The average thickness is 60 to 80 meter, with a maximum thickness of 700 meter in the Glückstadt-Graben.
The upper boundary is marked by dolomites, or claystones of the Grabfeld Formation.

## Fossil content

| Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon | Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |
The Erfurt Formation is known for its vertebrate fossils. Different kinds of fish, amphibians and archosauriforms have been found. Usually they are found as bone beds, but in 1977 the first complete skeletons were found near Kupferzell. They include Mastodonsaurus, Gerrothorax, Plagiosuchus, Callistomordax, Nanogomphodon, Batrachotomus, Kupferzellia and Palaeoxyris friessi.

### Reptiles

Reptiles reported from the Erfurt Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Batrachotomus | B. kupferzellensis | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | | An archosaur. |
| Wirtembergia | W. hauboldae | Vellberg. | Untere Graue Mergel. | 2 partial dentaries (SMNS 91060 & SMNS 91061), and a partial skeleton (SMNS 91313). | The oldest known rhynchocephalian. |
| Doswelliidae | Gen. et. sp. indet. | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | An osteoderm (MHI 2078). | An archosauriform. |
| Fraxinisaura | F. rozynekae | Vellberg, Baden-Württemberg. | Untere Graue Mergel Layer. | | A basal lepidosauromorph. |
| Jaxtasuchus | J. salomoni | Baden-Württemberg. | Estherienschichten to Anoplophora Dolomite. | Multiple skeletal remains. | A doswelliid. |
| Nothosaurus | N. cristatus | Eschenau Quarry, Baden-Württemberg. | Lettenkeuper. | Almost complete skull lacking mandible (GPIT/RE/09800). | A nothosaur |
| Nothosaurus | N. mirabilis | Hoheneck & Molsdorf. | Upper Lettenkeuper. | Multiple specimens. | A nothosaur. |
| Nothosaurus | N. sp. | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | 2 dorsal vertebrae & a thoracic rib. | A nothosaur. |
| Owenettidae, aff. Barasaurus | | Kupferzell locality & Schumann quarry. | | Left humerus (SMNS 92101) & right humerus (SMNS 92100). | An owenettid. |
| Pappochelys | P. rosinae | Schumann Quarry, Eschenau, Vellberg. | Top of Untere Graue Mergel. | 20 specimens. | A stem-turtle. |
| Polymorphodon | P. adorfi | Schumann Quarry, Vellberg. | Untere Graue Mergel. | Disarticulated partial skeletons. | An archosauriform. |
| Procolophonidae | Gen. indet. sp. indet. | Schumann Quarry. | | Left humerus (SMNS 91753). | A procolophonid. |
| Psephosaurus | P. suevicus | Quarry "Hohenloher Steinwerk" & Hoheneck near Ludwigsburg. | | Isolated plates (MHI 1426/1-3 & SMNS 91007). | A placodont. |
| Psephosaurus | P. sp. | Hoheneck near Ludwigsburg. | | Isolated plates (SMNS 91008 & 91009). | A placodont. |
| Rutiotomodon | R. tytthos | Schumann limestone quarry. | Top of the Untere Graue Mergel. | A nearly complete right maxilla with teeth (SMNS 97028) & a crushed dentary fragment (SMNS 97029). | A trilophosaurid. |
| Simosaurus | S. gaillardoti | Hoheneck near Ludwigsburg. | Lettenkeuper. | Skull. | A nothosaur. |
| Simosaurus | S. guilelmi | Hoheneck near Ludwigsburg. | Lettenkeuper. | Skull. | Junior synonym of S. gaillardoti. |
| Smilodon | S. laevis | Gaildorf Alumn Mine. | | Jaw fragment with teeth. | Preoccupied generic name, renamed Zanclodon laevis. |
| ?Suchia | Indeterminate | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | A tooth (MHI 2035). | An archosaur. |
| Tanystropheus | T. conspicuus | | | Vertebrae. | Nomen dubium. |
| Tanystropheus | T. sp. | Steinbach near Crailsheim. | Lower Lettenkeuper. | Teeth & vertebrae. | A tanystropheid. |
| Vellbergia | V. bartholomaei | Schumann Quarry, Vellberg. | Untere Graue Mergel. | Partial skull (SMNS 91590). | A stem-lepidosauromorph. |
| Zanclodon | Z. laevis | Gaildorf Alumn Mine. | | Jaw fragment with teeth. | An indeterminate archosaur. |

### Synapsids

Synapsids reported from the Erfurt Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Aff. Dinodontosaurus | | Neidenfels, Baden-Württemberg. | | Isolated complete left humerus (SMNS 56891). | Specimen now thought to represent a temnospondyl. | |
| Nanogomphodon | N. wildi | Michelbach an der Bilz. | Sandige Pflanzenschiefer Member, lower Lettenkeuper. | Teeth. | A cynodont. | |

### Amphibians

Amphibians reported from the Erfurt Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Bystrowiella | B. schumanni | Kupferzell & Vellberg, Hohenlohe. | Untere Graue Mergel. | Osteoderms & vertebrae. | A chroniosuchian. |
| Callistomordax | C. kugleri | Vellberg (Schumann quarry), Ummenhofen quarry & Kupferzell locality. | Albertibank through Untere Graue Mergel. | Numerous specimens. | A metoposauroid. |
| Gerrothorax | G. pulcherrimus | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | Two skull fragments and some osteoderms. | A plagiosaurid. |
| Mastodonsaurus | M. giganteus | Many localities in Baden-Württemberg, Bayern & in Thuringia. | From the Grenzbonebed through the Hohenecker Kalk, covering nearly the whole Lettenkeuper sequence. | Numerous specimens. | A capitosaur. |
| Megalophthalma | M. ockerti | Schumann limestone quarry, Vellberg, Baden-Württemberg, southern Germany. | Hauptsandstein (main sandstone unit). | A partial skull with anterior portion of the left mandibular ramus (MHI 2047). | A plagiosaurid. |
| Plagiosuchus | P. pustuliferus | Multiple localities in Baden-Württemberg & Thuringia. | Vitriolschiefer, Sandige Pflanzenschiefer & Untere Graue Mergel. | Multiple specimens. | A plagiosaurid. |
| ?Temnospondyli | Gen. et. sp. indet. | Neidenfels & Schumann Quarry. | Untere Graue Mergel. | Isolated complete left humerus (SMNS 56891) & isolated almost complete right humerus (SMNS 90571). | Originally thought to represent a dicynodont similar to Dinodontosaurus. |
| Trematolestes | T. hagdorni | Present in a range of localities in southern Germany. | Estherienschichten through Untere Graue Mergel, upper Lettenkeuper. | Numerous specimens including a nearly-complete skeleton. | A trematosaurid. |

### Bony fish

Bony fish reported from the Erfurt Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| "Ceratodus" | "C." concinnus | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | Tooth plates, pterygoids & scales. | A lungfish. |
| ?Coelacanthidae | Gen. et. sp. indet. | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | Numerous remains. | A coelacanth. |
| Parundichna | P. schoelli | Rot am See, Baden-Württemberg. | Hauptsandstein. | Clusters of sigmoidal scratches (MHI 1704). | Swimming trace of a large coelacanth. |
| Ptychoceratodus | P. serratus | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | A mould of a juvenile left praearticular tooth (MHI 410) & a fragment of a juvenile tooth plate (MHI 1748/42). | A lungfish. |
| ?Redfieldiiformes | Fam., gen. et. sp. indet. | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | 2 fragmentary and dissociated skeletons. | A redfieldiiform. |
| Saurichthys | S. gypsophilus | Franconia. | | Skull fragment. | A saurichthyiform. |
| Saurichthys | S. sp. | Schwäbisch Hall. | Albertischichten Member (Serreolepisbank). | 1 fragmentary rostrum (MHI 1748/27). | A saurichthyiform. |
| Serrolepis | S. suevicus | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | Numerous specimens. | A perleidiform. |

### Cartilaginous fish

Cartilaginous fish reported from the Erfurt Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Lonchidion | L. sp. | Schwäbisch Hall. | Albertischichten Member (Serrolepisbank). | Teeth. | A hybodontiform. | |
| Palaeoxyris | P. friessi | Muschelkalk quarry, Baden-Württemberg. | Top of Hauptsandstein. | SMNS 95447 (egg capsule). | Likely an egg capsule of Polyacrodus. | |