# Zagaje Formation

The Zagaje Formation is a Latest Triassic-Early Jurassic Epoch (Rhaetian-Sinemurian) geologic formation located mostly in Poland with layers also exposed in north Germany. This unit is known for its diverse Ichnofossil assemblages, with traces of invertebrates along vertebrate footprints, as well plants, large coal accumulations, invertebrate remains and ichnofossils. The Zagaje Formation correlates with The lower part of the Höganäs Formation in Scania, as well the Munkerup Member and the Gassum Formation in Denmark.

## Paleoenvironment

The Zagaje Formation is particularly visible in the Sołtyków region and is made mostly of Early Jurassic continental mudstone-sandstone deposits linked to the onset of "depositional sequence I". Its age is confirmed as mostly Early Hettangian through stratigraphic and paleontological analyses, including fossil flora and conchostraca findings. Sedimentological studies divide the Sołtyków profile into three parts: ephemeral reservoir deposits, floodplain and lacustrine sediments, and river channel deposits, highlighting dynamic depositional environments influenced by tectonic subsidence and varying hydrological conditions.
Climate wise, the area was located back in the Hettangian around 45°N paleolatitude in Laurasia within a rise of 5–10°C above present, where it experienced significant climatic and environmental change related with sea-level fluctuations, manifested locally with a notorious retrogradational fluvial-lacustrine sedimentation, with evidence of a humid climate interspersed with drier seasons. Some plant fossils like Hirmeriella mark points of aridity on what was mostly a humid swampy alluvial-lacustrine habitat.
The Zagaje Formation's deposits are known from both outcrops and borehole profiles that consist primarily of sandstones, mudstones, and interspersed coal and siderite layers. It represents a stratigraphic gap with the underlying Upper Triassic formations and is capped by a transgressive contact with the Skłoby Formation. This unit contains freshwater fauna and diverse trace fossils, including vertebrate tracks. The paleoenvironment reflects a dynamic alluvial plain shaped predominantly by high-sinuosity stream processes, transitioning from earlier braided and low-sinuosity stream systems. This evolution is attributed to climatic changes, rising base levels, and decreasing geomorphological gradients. Observations, both from exposures and borehole data, highlight the dominance of avulsion processes, with several depositional subsystems identified. Facies with organic remains are diverse: riverbed biofacies, derived from meandering channels characterized by fining-upward sequences composed of channel lag deposits, point-bar sands, and finer overlying sediments. These deposits exhibit lateral accretion bedding and significant fossil bivalves and large-sized floated plant remains (stems and trunks of large plants) consistent with subaqueous dune migration within the channels; levee deposits derived from successive floods with scarce root traces, while plant remnants are common; Paleosoils with sparse traces of plant roots and remains of floating plants of highly variable size (mainly organic detritus, but also fragments of wood), fragments of bivalve shells and vertebrate remains (amniote bones, tracks, fish scales); the biofacies of the ephemeral water reservoir with plant remains, mainly horsetails, and fossils of insects, ostracods, and conchostraca; The pedogenic soil biofacies with remains of plant roots with preserved organic matter and rhizomes and stems in a living position; Floodplain biofacies with traces of numerous plant roots and plant macroremains, and remains of sedge stems preserved in a living position; Lake-marsh biofacies, dark, laminated mudstones with plant roots and coal, with few fossil bivalves, a large amount of organic matter in the form of plant detritus, and layers of coal and numerous finds of miospores and megaspores. The local presence of charcoal fragments and high concentrations of PAHs, along with possible burnt plants, provides evidence for wildfires in the region, that likely occurred near the surface with charred wood fragments were subsequently incorporated into sediments by river transport.
The high presence of coprolites has allow also to stablish the tropic chain of the local biota, with a clear full ecosystemical substitution of the older Triassic archosaurs by Dinosaurs.

## Biota
### Indet. Invertebrates

Several unname Ichnofossils are recovered at Soltyków, including conical domichnia (Conichnus?), bivalve straight to winding linear trails, smooth vertical and subvertical branching tunnels, knob-walled tunnels, mace-shaped or irregular ellipsoid chambers, etc.
| Genus | Species | Location | Material | Made By |
| Cruziana | C. problematica cf.C. isp | Soltyków | Dwelling structures | Annelids Insect larvae Nematodes |
| Cochlichnus | C. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Traces | Annelids Insect larvae Nematodes |
| Conichnus | C. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Subcylindrical burrows | Annelids Nematodes Crustaceans |
| Diplichnites | D. isp. | Soltyków | Hypichnial trackway | Insects Myriapods Arachnids |
| Diplocraterion | D. parallelum | Gromadzice Kontrewers Odrowaz Soltyków | U-Shaped Burrows | Crustaceans Annelids Poronidans Insects Fish |
| Imbrichnus | I. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Burrows | Annelids Bivalves Crustaceans |
| Kouphichnium | cf. K. isp. | Soltyków | V-shaped hypichnial marks | Xiphosura Malacostraca |
| Palaeophycus | P. isp. | Soltyków | Straight or slightly curved burrows | Annelids Bivalves Crustaceans |
| Planolites | P. isp. | Soltyków | Horizontal burrows | Annelids Bivalves Crustaceans |
| Rusophycus | R. isp. | Soltyków | Resting Traces | Resting traces of arthropods |
| Scolicia | S. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Moving Traces | Locomotion trace of gastropods |
| Scoyenia | S. isp. | Soltyków | Linear slender burrows | Beetles? |
| Skolithos | S. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Sac/Bottle shaped burrows | Annelids Crustaceans Insects |
| Spongeliomorpha | S. carlsbergi S. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Sac/Bottle shaped burrows | Annelids Crustaceans Insects |

### Molluscs

Indeterminate gastropod egg capsules are known, similar to the ones recovered in the extant Neritina. 4 unnamed morphotypes of freshwater bivalves of the family Unionidae are known.
| Genus | Species | Location | Material | Notes | Images |
| Anodonta | A. liasokeuperina | Soltyków | Isolated Shells | A freshwater mussel, member of the family Unionidae | Example of extant specimen of Anodonta |
| Calceoformites | C. uchmani | Soltyków | Clog-shaped protrusions | Bivalve estabilization traces | |
| Cardinia | C. follini C. inglensis C. cf.kullensis | Gromadzice Odrowaz Podole Soltyków | Isolated Shells | A Carditidae Bivalve. Indicator of oligohaline settings and found also on the younger Skłoby Formation | |
| Lockeia | L. siliquaria L. amygdaloides L. czarnockii | Gromadzice Kontrewers Odrowaz Soltyków | Dwelling traces | Resting traces of Bivalves | |
| Ptychoplasma | P. conica | Soltyków | Locomotion trace | Gastropod Locomotion traces | |
| Scalichnus | S. phiale S. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Sac/Bottle shaped burrows | Escape structure of mud-dwelling bivalves | |
| Scolicia | S. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Traces | Locomotion and feeding trace of gastropods | |
| Unio | U. minutus | Soltyków | Isolated Shells | A freshwater mussel, member of the family Unionidae | Example of extant specimen of Unio |
| Viviparus | V. spp. | Soltyków | Isolated Shells | A freshwater snail, member of the family Viviparidae | Example of extant specimen of Viviparus |

### Crustacea

| Genus | Species | Stratigraphic position | Material | Notes | Images |
| Bulbilimnadia | B. kilianorum | Hucisko Soltyków | Valves | A freshwater Ostracodan of the family Bulbilimnadiidae | |
| Darwinula | D. sarytirmenensis D. spp. | Gromadzice Hucisko Odrowaz Soltyków | Valves | A freshwater Ostracodan of the family Darwinulidae | Example of Darwinula specimens |
| Euestheria | E. opalina E. loczyi E. brodieana E. minuta Euestheria sp. | Gromadzice Hucisko Kontrewers Odrowaz Soltyków | Valves | A Freshwater Clam shrimp (Phyllopodan) of the family Lioestheriidae. | |
| Isopodichnus | I. isp. | Gromadzice Kontrewers Odrowaz Soltyków | Hypichnial marks | Feeding and moving traces of phyllopod and notostracan crustaceans | |

### Insects

Radial chambers around large tunnels have been recovered, they may be arthropod burrows or traces of roots. Large nest structures with septa, similar to nesting behaviour of insects like Cicadas are known.
| Genus | Species | Location | Material | Notes |
| Artematopodites | A. ssp. | Odrowaz | MPK 5/36, 39, 40 | A Coleopteran, member of the family Permosynidae |
| Blattodea | Indeterminate | Odrowaz | MPK 5/54 | Indeterminate Blattodean remains |
| Blattulidae | Indeterminate | Odrowaz | MPK 5/1 | Indeterminate Cockroach remains |
| Caraboidea | Indeterminate | Odrowaz | MPK 5/12, 15 | Indeterminate Beetle remains |
| Coleoptera | Indeterminate | Odrowaz | Isolated Wings | Indeterminate Beetle remains |
| Helminthoidichnites | cf. H. isp. | Sołtyków | Gnawing traces | surficial gnawing traces made by insects |
| Hydrobiites | H. sp. | Odrowaz | MPK 5/10, 13, 17, 22, 25, 33 | A Coleopteran, member of the family Permosynidae |
| Linckichnus | L. terebrans | Sołtyków | Boring Traces | Detritivorous habitation dwellings or oviposition structures of insects in dead wood |
| Memptus | M. sp. | Odrowaz | MPK 5/44 | A Coleopteran, Incertade sedis |
| Notocupes | N. sp. | Odrowaz | MPK 5/6 | A Coleopteran, Incertade sedis |
| Odrowazicoris | O. polonicus | Odrowaz | MPK 5/2 | A Hemipteran, member of the family Belostomatidae |
| Polysitum | P.? sp. | Odrowaz | MPK 5/14, 29 | A Coleopteran, Incertade sedis |
| Phoroschizidae | Indeterminate | Odrowaz | MPK 5/4,5, 8, 20, 35 | Indeterminate Beetle remains |
| Xylonichnus | Cf.X. isp. | Sołtyków | Boring Traces | Borings in the wood made probably by insect larvae |

### Fish

Unidentified Actinopterygian fish scales and teeth were collected from clayish, organic-rich lake deposits, while some coprolites have been referred to Hybodontiform sharks.
| Genus | Species | Location | Material | Notes | Images |
| Semionotus | S. cf. bergeri | Czarniecka Góra | Single specimen | A Semionotiform bony fish of the family Semionotidae | |
| Paleoniscidae | Indeterminate | Sołtyków | Scales & Teeth | Indeterminate Palaeonisciformes specimens | |

### Testudinata

| Genus | Species | Location | Material | Notes | Images |
| Chelonipus | C. isp. | Sołtyków | Footprints | Turtle Tracks | |
| Testudinata | Indeterminate | Sołtyków | Carapace Fragments | Unidentified Turtle remains, quoted to belong to a large sized taxon | |

### Synapsids

| Genus | Species | Location | Material | Notes | Images |
| Ameghinichnus | Cf.A. isp. | Sołtyków | Footprints | Small Synapsid tracks, likely from Mammaliaformes | A genus similar to Morganucodon is most probably the best candidate for the local Brasilichnium footprints |
| Brasilichnium | B. isp. | Sołtyków | Footprints | Small Synapsid tracks, likely from Mammaliaformes | A genus similar to Morganucodon is most probably the best candidate for the local Brasilichnium footprints |
| Dicynodontipus | D. isp. | Sołtyków | Footprints | Tracks referred to Eucynodonts, maybe Tritylodontidae | A genus similar to Tritylodon is most probably the best candidate for the local Dicynodontipus & Therapsipus footprints |
| Therapsipus | Cf.T. isp. | Sołtyków | Footprints | Tracks referred to Eucynodonts | A genus similar to Tritylodon is most probably the best candidate for the local Dicynodontipus & Therapsipus footprints |

### Rhynchocephalia

| Genus | Species | Location | Material | Notes | Images |
| Rhynchosauroides | R. isp. | Sołtyków | Footprints | Tracks referable to both Sphenodontidae and Lepidosauromorpha | A small taxon coeval in age like Gephyrosaurus is a good reference for the local Rhynchosauroides tracks |

### Crocodrylomorphs

| Genus | Species | Location | Material | Notes | Images |
| Batrachopus | B. isp. | Sołtyków | Footprints | Crocodrylomorph Tracks, likely of terrestrial taxa | Terrestrial crocodylomorphs such as Protosuchus, were most likely the Batrachopus trackmakers. |
| Crocodylomorpha | Indeterminate | Sołtyków | Bones inside a large bromalite | An Indeterminate Crocodrylomorph, likely preyed on by a large Theropod | |
| Crocodylomorpha | Indeterminate | Sołtyków | Footprints | Unnamed 3rd type of Footprint | |
| Malutitetrapodiscus | Cf.M. isp. | Sołtyków | Footprints | Probably left by small terrestrial crocodylomorphs | |

### Pterosauria

| Genus | Species | Location | Material | Notes | Images |
| Pteraichnus | cf. P. isp. | Sołtyków | Footprints | Pterosaur Tracks, the individuals that left them probably had a wingspan of about 30-40 cm | A small taxon coeval in age like Dimorphodon is a good reference for the local Pteraichnus tracks |

### Theropods

Some elliptical "post-egg" structures egshells & eggs with embryo remains have been referred to theropods, yet may also belong to Ornithischians.
| Genus | Species | Location | Material | Notes | Images |
| Anchisauripus | A. ispp. Cf.A. isp. | Sołtyków | Footprints | Adscribed to smal slender primitive predatory dinosaurs, related with genera such as Coelophysis | Anchisauripus may belong to a genus similar to Procompsognathus |
| Eubrontes | E. isp. Cf.E. isp. | Sołtyków | Footprints | Eubrontes is related to the Genus Dilophosaurus, representing a basal Neotheropods | Oudated Dilophosaurus model nicknamed "Dyzio", who was done in honor of the Zagaje Finds |
| Grallator | G. ispp. Cf.G. isp. | Sołtyków | Footprints | Similar pes with Coelophysidae-alike dinosaurs, related with neotheropods such as Dracoraptor. | Grallator footprints may belong to a genus similar to Dracoraptor |
| Kayentapus | K. soltykovensis K. ispp. Cf.K. isp. | Sołtyków | Footprints | Assumed to come from Genera similar to Sarcosaurus | Kayentapus footprints may belong to a genus similar to Sarcosaurus |
| Megalosauripus | Cf.M. isp. | Sołtyków | Footprints | Large bodied taxa, maybe related with Sinosaurus. Among the largest early Jurassic theropod tracks worldwide. | Megalosauripus footprints can belong to a large relative of Sinosaurus or regional taxa such as Dornraptor |
| Plesiornis | cf. P. isp. | Sołtyków | Footprints | Theropod Tracks from small sized taxa with convergent features with latter Avians | |
| Stenonyx | Cf.S. isp. | Sołtyków | Footprints | Small Theropod tracks, likely from juveniles of larger taxa | |
| Theropoda | Indeterminate | Hucisko Sołtyków | Teeth Isolated Bones Bromalites | Some coprolites, referred to Theropods include plant material, probably ingested acidentally by drinking water. Others include large bone remains or fish scales. Teeth corroborate the presence of large taxa in the area. | |

### Sauropodomorpha

| Genus | Species | Location | Material | Notes | Images |
| Kalosauropus | K. pollex | Gromadzice | Footprints | Tracks referred to early quadrupedal or semibipedal sauropodomorphs | Local Kalosauropus resemble the feet of the genus Massospondylus |
| Megaloolithidae? | Indeterminate | Sołtyków | Eggshells, eggs with embryo remains & spherical "post-egg" structures | Nesting structures & associated eggs referred to sauropods | Example of Megaloolithus, a fossil Sauropod egg |
| Otozoum | Cf.O. isp. | Sołtyków | Footprints | Tracks referred to early quadrupedal or semibipedal sauropodomorphs | |
| Parabrontopodus | P. isp. | Sołtyków | Footprints | Sauropod tracks, usually referred to taxa similar to Vulcanodon | Local Parabrontopodus resemble the feet of the genus Vulcanodon |
| Sauropodomorpha | Indeterminate | Hucisko | Isolated bones Bromalites | Indeterminate Sauropodomorph bones | |
| Tetrasauropus | Cf.T. isp | Sołtyków | Footprints | Tracks referred to early quadrupedal or semibipedal sauropodomorphs | Local Tetrasauropus resemble the feet of the genus Aardonyx |

### Ornithischia

| Genus | Species | Location | Material | Notes | Images |
| Anomoepus | A. scambus A. ispp. Cf.A. isp. | Sołtyków Gromadzice | Footprints | Tracks that resemble the feet of "Stormbergia" and various Genasauria of different sizes | "Stormbergia"´s feet matches with the Anomoepus tracks |
| Delatorrichnus | D. isp. | Sołtyków | Footprints | Tracks usually referred to Heterodontosauridae or similar taxa | Heterodontosaurus's feet matches with the Delatorrichnus tracks |
| Moyenisauropus | M. karaszevskii M. isp. Cf.M. isp. | Kontrewers | Footprints | Tracks adscribed to basal Thyreophora, vinculated with genera such as Scelidosaurus | Scelidosaurus feet matches with the Moyenisauropus trackmaker |

### Plants

In Palynology, the Zagaje Formation belongs to the Nathorstisporites hopliticus assemblage (Isoetales), indicating a spike in marshland and lacustrine settings. The Sołtyków outcrop is dominated by Classopollis (Cheirolepidiaceae), Aratrisporites (Cycadidae), Concavisporites (Dipteridaceae) and Cyathidites (Cyatheaceae).
| Genus | Species | Stratigraphic position | Material | Notes | Images |
| Aciphyllum | A. triangulatum | Sołtyków | Cuticles | Affinities with Pinaceae inside Pinales. The oldest record of a Pinus-like needle in the fossil record | |
| Brachyphyllum | B. sp. | Sołtyków | Cuticles | Affinities with Cheirolepidiaceae or Araucariaceae inside Pinales | Brachyphyllum specimen |
| Caytonia | C. sp. | Odrowąż Sołtyków | Reproductive structure | Affinities with Caytoniaceae in the Caytoniales | |
| Czekanowskia | C. sp. | Hucisko | Branched Shoots | Affinities with the Czekanowskiales inside Ginkgoopsida. This Genus is related with relatively drier-cooler conditions. | |
| Desmiophyllum | D. harrisii | Sołtyków | Cuticles | A possible Conifer leaf, recent finds of it associated with the cone genera Sphaerostrobus and Ourostrobus points to a coniferophyte affinity, maybe as a member of Palissyaceae. | |
| Dictyophyllum | D. sp. | Odrowąż Sołtyków | Pinnae | Affinities with Dipteridaceae inside Gleicheniales. | Dictyophyllum specimen |
| Goepertella | G. microloba | Odrowąż Sołtyków | Pinnae | Affinities with Dipteridaceae inside Gleicheniales | |
| Hirmeriella | H. muensteri | Hucisko Odrowąż | Branched Shoots and reproductive cones | Affinities with the Cheirolepidiaceae inside Pinales. | |
| Komlopteris | K. distinctiva | Odrowąż Sołtyków | Cuticles | Affinities Corystospermaceae inside Corystospermales. | |
| Matonia | M. braunii | Niekłań PGI-1 | Pinnae | Affinities with Matoniaceae inside Gleicheniales | |
| Neocalamites | N. lehmannianus | Sołtyków | Stems | Affinities with Calamitaceae inside Equisetopsida. A common horsetail on the Liassic of Europe. | Neocalamites specimens |
| Nilssonia | N. sp. | Sołtyków | Cuticles | Affinities with Cycadeoidaceae in the Bennettitales or alternatively a member of Nilssoniales | Nilssonia specimen |
| Odrolepis | O. liassica | Odrowąż Sołtyków | Complete Plants | Affinities with Lycopodiales | |
| Otozamites | O. brevifolius | Odrowąż Sołtyków | Leaflets | Affinities with Williamsoniaceae in the Bennettitales. | Otozamites specimen |
| Pachypteris | P. lanceolata P. papillosa | Odrowąż Sołtyków | Pinnae | Affinities Corystospermaceae inside Corystospermales. | |
| Paracycas | P. minuta | Odrowąż Sołtyków | Leaflets | Affinities with Cycadales in the Cycadopsida. | |
| Piroconites | P. kuespertii | Odrowąż Sołtyków | Reproductive structure | Affinities with Gnetales, maybe with Welwitschiaceae | |
| Phlebopteris | P. angustiloba | Odrowąż Sołtyków | Cuticles | Affinities with Matoniaceae in the Gleicheniales. | Phlebopteris specimen |
| Podozamites | P. cf. schenkii  P. sp. Cf. P. sp. | Sołtyków | Branched shoots | Affinities with Krassiloviaceae inside Voltziales | Podozamites reconstruction |
| Pseudotorellia | Cf.P. sp. | Sołtyków | Cuticles | Affinities with the Pseudotorelliaceae inside Ginkgoopsida. | |
| Pterophyllum | P. sp. Cf.P. sp. | Odrowąż Sołtyków | Leaflets | Affinities with Williamsoniaceae in the Bennettitales. | Pterophyllum specimen |
| Ptilozamites | P. cycadea | Sołtyków | Cuticles | Affinities Corystospermaceae inside Corystospermales. | |
| Sagenopteris | S. nilssoniana | Odrowąż Sołtyków | Leaves | Affinities with Caytoniaceae in the Caytoniales | Sagenopteris specimen |
| Schmeissneria | S. microstachys | Odrowąż Sołtyków | Reproductive structure | Affinities with Ginkgoopsida or with Angiosperm-convergent Gimnosperms | |
| Swedenborgia | S. sp. | Sołtyków | Branched Shoots | Affinities with Krassiloviaceae inside Voltziales. | Swedenborgia specimens |
| Thaumatopteris | T. brauniana | Hucisko Odrowąż | Pinnae | Affinities with Dipteridaceae inside Gleicheniales | |
| Todites | T. princeps | Hucisko Odrowąż | Pinnae | Affinities with Osmundaceae in the Osmundales. | |