# Xinminbao Group

The Xīnmínbǎo Group (Chinese: 新民堡群; pinyin: Xīnmínbǎo qún) is a group of geological formations in north central China. They occur across a large depression between the Altai Mountains of Mongolia to the north and the Qilian mountains of the Qinghai Plateau to the south, in the Gōngpóquán (公婆泉) and Suànjǐngzi (算井子) basins, and also in the neighbouring Jiuquan Basin.
Both of these areas are inland basins consisting of fluvial (river), lacustrine (lake), and intermontane (between mountains) alluvial fan (floodplain) sediments that were deposited during the Early Cretaceous, probably during the Aptian or possibly late Barremian stage, when the climate was semi-arid and subtropical.
The group has been visited by many expeditions including the Silk Road dinosaur expedition of 1992 which concentrated on the area around Mazong Shan.

## Geology

The group is made up of three main formations.

### Chijinbao Formation

This consists of a lower red unit of coarse conglomerates grading to fine sandstones representing river channel to alluvial fan deposits, and an upper unit of red clastic sediments from either overbank deposits in a meandering fluvial environment, or accumulation in a shallow lacustrine or paludal (marsh) environment.

### Digou Formation

This consists of grey siltstones and calcareous mudstones comprising two sequences of fluvio-lacustrine sedimentation with some alluvial fan and littoral (lake-shore) deposits.

### Zhonggou Formation

This consists of red siltstones and mudstones in a series of upwardly coarsening cycles of lacustrine sediments.

## Vertebrate fauna

The dinosaurs of the Xinminbao Group are collectively referred to as the Mazongshan Dinosaur Fauna, representing a unique dinosaur assemblage from all other known dinosaur faunas.

### Ceratopsians

Ceratopsians reported from the Xinminbao Group :
| Genus | Species | Material | Images |
| Archaeoceratops | Archaeoceratops oshimai | "[Two] individuals lacking forelimbs." | Archaeoceratops Auroraceratops |
| Auroraceratops | Auroraceratops rugosus | | Archaeoceratops Auroraceratops |
| Microceratus | Microceratus gobiensis | | Archaeoceratops Auroraceratops |
| Microceratus | Microceratus sulcidens | | Archaeoceratops Auroraceratops |
| Psittacosaurus | Psittacosaurus mazongshanensis | "One individual lacking caudal and hindlimb." | Archaeoceratops Auroraceratops |

### Ornithopods

| 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. |
Ornithopods reported from the Xinminbao Group :
| Genus | Species | Material | Notes |
| Equijubus | Equijubus normani | "Skull and partial postcranial skeleton." | (both this and Probactrosaurus are properly hadrosauroids rather than hadrosaurids) |
| Gongpoquansaurus | Gongpoquansaurus mazongshanensis | "Partial skull and postcranial skeleton." | |
| Siluosaurus | Siluosaurus zhangqiani | "Teeth." | Nomen dubium, tentatively classified as a Hypsilophodontid. |

### Saurischians

Saurischians reported from the Xinminbao Group :
| Genus | Species | Material | Notes | Images |
| Asiatosaurus | Asiatosaurus mongoliensis | | | Beishanlong Sinornithoides |
| Beishanlong | Beishanlong grandis | | A deinocheirid ornithomimosaur. | Beishanlong Sinornithoides |
| Chiayusaurus | C. lacustris | | | Beishanlong Sinornithoides |
| Gobititan | Gobititan shenzhouensis | | | Beishanlong Sinornithoides |
| "Nanshiungosaurus" | "Nanshiungosaurus bohlini" | "[Sixteen] cervical and dorsal vertebrae." | This species does not belong to Nanshiungosaurus. | Beishanlong Sinornithoides |
| Sinornithoides | Indeterminate | | | Beishanlong Sinornithoides |

### Thyreophorans

Indeterminate ankylosaur remains are known from the group.
| 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. |
Thyreophorans of the Xinminbao Group :
| Genus | Species | Location | Stratigraphic position | Abundance | Notes |
| Stegosaurides | Stegosaurides excavatus | | | | (nomen dubium) |

### Crocodilians

Indeterminate crocodilian remains are known from the group.
Crocodilians reported from the Xinminbao Group :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Chiayusuchus | Chiayusuchus cingulatus | | | | | |

### Fish

Ray-finned fishes reported from the Xinminbao Group :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Xixiaichthys | Xixiaichthys tongxinensis | | | | | |

### Pterosaurs

Pterosaurs reported from the Xinminbao Group :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Noripterus | Indeterminate | | | | | Noripterus |

### Turtles

Turtles of the Xinminbao Group :
| Genus | Species | Location | Stratigraphic position | Abundance | Notes |
| Tsaotanemys | Tsaotanemys rugosus | | | | |