# Paleobiota of the Djadochta Formation

The Djadochta Formation (sometimes spelled Djadokhta, Djadokata, or Dzhadokhtskaya) is a geological formation in the Gobi Desert of Mongolia. It dates to the Campanian stage of the Late Cretaceous and is famous for its dinosaur fossils including Oviraptor, Protoceratops, and Velociraptor. It is also known for a high diversity of mammal and lizard fossils, and a complete catalogue of its fossil contents is shown below.
| 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. |

## Vertebrates
### Amphibians

| Genus | Species | Location | Material | Notes | Images |
| Gobiates | Indeterminate | Udyn Sayr | "Partial skeleton with partial urostyle." | A frog. | |

### Crocodylomorphs

| Genus | Species | Location | Material | Notes |
| Artzosuchus | A. brachicephalus | Udyn Sayr | "Partial skull." | A crocodylomorph. |
| Gobiosuchus | G. kielanae | Bayn Dzak | "Multiple specimens with partial skulls and skeletons." | A gobisuchid. |
| Gobiosuchus | G.? parvus | Udyn Sayr | "Partial skull and skeleton." | A gobisuchid. |
| Shamosuchus | S. djadochtaensis | Bayn Dzak, Ukhaa Tolgod | "Two skulls and partial skeleton." | A paralligatorid. |

### Lizards

| Genus | Species | Location | Material | Notes |
| Adamisaurus | A. magnidentatus | Bayn Dzak, Tugriken Shireh, Ukhaa Tolgod | "Skulls and skeletons from multiple specimens." | A teiid. Also present in the Barun Goyot Formation and Bayan Mandahu Formation. |
| Aiolosaurus | A. oriens | Ukhaa Tolgod | "Incomplete skull and partial skeleton." | A varanoid. |
| Carusia | C. intermedia | Bayn Dzak, Ukhaa Tolgod | "Skulls from multiple specimens." | A carusiid. Also present in the Barun Goyot Formation and Bayan Mandahu Formation. |
| Cherminotus | C. longifrons | Tugriken Shireh, Ukhaa Tolgod | "Skulls and partial skeleton." | A varanoid. Also present in the Barun Goyot Formation. |
| Ctenomastax | C. parva | Zos | "Incomplete skull." | An iguanid. Also present in the Barun Goyot Formation. |
| Dzhadochtosaurus | D. giganteus | Tugriken Shireh | "Partially complete skull." | A macrocephalosaur. |
| Eoxanta | E. lacertifrons | Ukhaa Tolgod | "Incomplete skull." | A scincomorph. Also present in the Barun Goyot Formation. |
| Estesia | E. mongoliensis | Bayn Dzak, Ukhaa Tolgod | "Partial skulls and teeth." | A monstersaur. Also present in the Barun Goyot Formation. |
| Flaviagama | F. dzerzhinskii | Tugriken Shireh | "Skull and two vertebrae." | A priscagamid. |
| Globaura | G. venusta | Bayn Dzak, Ukhaa Tolgod | "Partial skulls." | A scincomorph. Also present in the Barun Goyot Formation. |
| Gobiderma | G. pulchrum | Udyn Sayr, Ukhaa Tolgod | "Skulls and skin impressions." | A monstersaur. Also present in the Barun Goyot Formation. |
| Gobinatus | G. arenosus | Ukhaa Tolgod | "Partial skull." | A teiid. Also present in the Barun Goyot Formation. |
| Hymenosaurus | H. clarki | Ukhaa Tolgod | "Partial skull." | A scincomorph. |
| Isodontosaurus | I. gracilis | Bayn Dzak, Tugriken Shireh, Ukhaa Tolgod, Zos | "Numerous skulls and a partial skeleton." | An iguanian. Also present in the Bayan Mandahu Formation. |
| Macrocephalosaurus | Indeterminate | Ukhaa Tolgod | "Partial skull and skeleton." | A teiid. Also present in the Barun Goyot Formation. |
| Mimeosaurus | M. crassus | Bayn Dzak, Ukhaa Tolgod, Zos Wash | "Partially complete skulls." | An acrodont. Also present in the Bayan Mandahu Formation. |
| Myrmecodaptria | M. microphagosa | Ukhaa Tolgod | "Single skull." | A gekkotan. |
| Ovoo | O. gurval | Little Ukhaa Tolgod | "Partial skull." | A varanid. |
| Parmeosaurus | P. scutatus | Ukhaa Tolgod | "Articulated skull and skeleton." | A scincomorph. |
| Phrynosomimus | P. asper | Ukhaa Tolgod | "Two partial skulls." | An acrodont. Also present in the Barun Goyot Formation. |
| Priscagama | P. gobiensis | Bayn Dzak, Ukhaa Tolgod | "Incomplete skulls." | An priscagamid. Also present in the Barun Goyot Formation. |
| Saichangurvel | S. davidsoni | Ukhaa Tolgod | "Complete skull and skeleton in articulation." | An iguanian. |
| Slavoia | S. darevskii | Ukhaa Tolgod | "Skulls and skeleton." | A scincomorph. Also present in the Barun Goyot Formation. |
| Telmasaurus | T. grangeri | Bayn Dzak | "Partial skull and skeleton." | A varanid. |
| Temujinia | T. ellisoni | Tugriken Shireh, Ukhaa Tolgod | "Several partial skulls." | An iguanid. |
| Tchingisaurus | T. multivagus | Ukhaa Tolgod | "Partial skull." | A teiid. |
| Unnamed scincomorph | Indeterminate | Ukhaa Tolgod | "Partial skull." | A scincomorph. |
| Varanoidea indet. | Indeterminate | Ukhaa Tolgod | "Partial maxilla and vertebra." | A varanoid. |
| Zapsosaurus | Z. sceliphros | Tugriken Shireh | "Two partial skulls." | An iguanid. |

### Mammals
#### Multituberculates

| Genus | Species | Location | Material | Notes |
| Bulganbaatar | B. nemegtbaataroides | Bayn Dzak, Ukhaa Tolgod | "Partial skull, and other remains." | A djadochtatherioid. |
| Catopsbaatar | C. catopsaloides | Ukhaa Tolgod | Not specified. | A djadochtatheriid. Also present in the Barun Goyot Formation. |
| Chulsanbaatar | C. vulgaris | Ukhaa Tolgod | "Skull and partial skeleton." | A djadochtatherioid. Also present in the Barun Goyot Formation. |
| Djadochtatherium | D. matthewi | Bayn Dzak, Tugriken Shireh | "Partial skulls." | A djadochtatheriid. |
| Deltatheroides | D. cretacicus | Bayn Dzak | "Partial skull." | A djadochtatheriid. |
| Kamptobaatar | K. kuczynskii | Bayn Dzak, Ukhaa Tolgod | "Partial skull, and other remains." | A sloanbaatarid. |
| Kryptobaatar | K. dashzevegi | Bayn Dzak, Tugriken Shireh, Ukhaa Tolgod | "Skulls and skeleton remains from several specimens." | A djadochtatheriid. Gobibaatar and Tugrigbaatar are considered synonyms of this taxon. |
| Mangasbaatar | M. udanii | Udyn Sayr | "Skulls and partial skeleton from two specimens." | A djadochtatheriid. |
| Nemegtbaatar | N. gobiensis | Ukhaa Tolgod | Not specified. | A djadochtatherioid. Also present in the Barun Goyot Formation. |
| Sloanbaatar | S. mirabilis | Bayn Dzak, Ukhaa Tolgod | "Complete skull, and other remains." | A sloanbaatarid. |
| Tombaatar | T. sabuli | Ukhaa Tolgod | "Partial skull." | A djadochtatheriid. |

#### Therians

| Genus | Species | Location | Material | Notes |
| Asiatherium | A. reshetovi | Udyn Sayr | "Articulated skull and skeleton." | A metatherian. |
| Deltatheridium | D. pretrituberculare | Bayn Dzak, Ukhaa Tolgod | "Partial skull and skeleton remains." | A metatherian. |
| Hyotheridium | H. dobsoni | Bayn Dzak | "Partial skull." | A therian. |
| Hyotheridium | Indeterminate | Ukhaa Tolgod | Not specified. | A therian. |
| Kennalestes | K. gobiensis | Bayn Dzak, Ukhaa Tolgod | "Nearly complete skull, and other remains." | An eutherian. |
| Maelestes | M. gobiensis | Ukhaa Tolgod | "Partial skull with skeleton." | A cimolestid. |
| Ukhaatherium | U. nessovi | Ukhaa Tolgod | "Partial to nearly complete skeletons from several specimens." | An eutherian. |
| Zalambdalestes | Z. lechei | Bayn Dzak, Tugriken Shireh | "Skulls and skeletons from several specimens." | An eutherian. |

### Pterosaurs

| Genus | Species | Location | Material | Notes | Images |
| Azhdarchidae indet. | Indeterminate | Tugriken Shireh | "Indeterminate bone inside the gut cavity of a Velociraptor." | An azhdarchid. | |

### Turtles

| Genus | Species | Location | Material | Notes |
| Nanhsiungchelyidae indet. | Indeterminate | Abdrant Nuru | "Three shell fragments." | A nanhsiungchelyid. |
| Nanhsiungchelyidae indet. | Indeterminate | Bayn Dzak | "Partial shells." | A nanhsiungchelyid. |
| Nanhsiungchelyidae indet. | Indeterminate | Udyn Sayr | "Two shell fragments." | A nanhsiungchelyid. |
| Zangerlia | Z. dzamynchondi | Zamyn Khondt | "Partial shell." | A nanhsiungchelyid. |
| Zangerlia | Z. ukhaachelys | Ukhaa Tolgod | "Partial skull and skeleton." | A nanhsiungchelyid. |

### Dinosaurs
#### Ankylosaurids

| Genus | Species | Location | Material | Notes |
| Minotaurasaurus | M. ramachandrani | Ukhaa Tolgod | [Two] complete skulls, mandibles, and first cervical half-ring. | An ankylosaurid previously thought to be a junior synonym of Tarchia, but is now considered to be a valid and distinct taxon. |
| Pinacosaurus | P. grangeri | Bayn Dzak, Ukhaa Tolgod | [Three] skulls, mandibles, predentary, cervical vertebrae, dorsal vertebrae, caudal vertebrae, ribs, scapula, coracoids, humerus, radius, ulna, ilium, femora, tibia, fibula, pelvis, manus, tail club handles, cervical half-rings, osteoderms, and a nearly complete skeleton lacking a skull. | An ankylosaurid also known from the Alagteeg Formation and Bayan Mandahu Formation. |
| Ankylosauridae indet. | Indeterminate | Zamyn Khondt | Partially complete postcranial skeleton with in situ osteoderms. | Previously referred to Saichania, but is now referred to as Ankylosauridae indet., or cf. Pinacosaurus. |

#### Marginocephalians

| Genus | Species | Location | Material | Notes |
| Bainoceratops | B. efremovi | Bayn Dzak | "Partial vertebrae." | A protoceratopsid. May be synonymous with Protoceratops. |
| Bagaceratops | Indeterminate | Udyn Sayr | "Skull with partial skeleton." | A protoceratopsid. Indeterminate between Bagaceratops and Protoceratops. |
| Goyocephale | G. lattimorei | Boro Khovil | "Partial skull and skeleton." | A pachycephalosaurid. Locality sediments may belong to this formation. |
| Protoceratops | P. andrewsi | Bayn Dzak, Tugriken Shireh, Udyn Sayr, Zamyn Khondt | "Multiple partial to complete specimens." | A protoceratopsid. |
| Protoceratops | P. hellenikorhinus | Bor Tolgoi, Udyn Sayr | "Partial cranial remains." | A protoceratopsid. |
| Protoceratopsidae indet. | Indeterminate | Ukhaa Tolgod | "Numerous skulls and remains." | A protoceratopsid. |
| Udanoceratops | U. tschizhovi | Udyn Sayr | "Skull and fragmented skeleton elements." | A giant leptoceratopsid. |

#### Ornithopods

| Genus | Species | Location | Material | Notes | Images |
| Hadrosauroidea indet. | Indeterminate | Tugriken Shireh | "Fragmented remains from juveniles." | A hadrosauroid. | |
| Plesiohadros | P. djadokhtaensis | Alag Teeg | "Skull and partial body elements." | A hadrosauroid. Actually hails from the Alagteeg Formation. | |

#### Sauropods

| Genus | Species | Location | Material | Notes | Images |
| Sauropoda indet. | Indeterminate | Not specified. | Not specified. | A sauropod. |

#### Theropods
##### Alvarezsaurs

| Genus | Species | Location | Material | Notes | Images |
| Alvarezsauridae indet. | Indeterminate | Tugriken Shireh | "Partial skull, braincase, and skeleton elements of two specimens." | An alvarezsaurid also known as the Tugriken Shireh alvarezsaur. Uncertainly referred as Parvicursor sp. | Kol ghuva Shuvuuia deserti |
| Kol | K. ghuva | Ukhaa Tolgod | "A well-preserved right foot." | A large alvarezsaurid. Its classification has been criticized. | Kol ghuva Shuvuuia deserti |
| Shuvuuia | S. deserti | Ukhaa Tolgod | "Multiple specimens with skull and skeletons." | An alvarezsaurid. | Kol ghuva Shuvuuia deserti |
| Undescribed Alvarezsauridae | Indeterminate | Bayn Dzak | "Partial pelvic girdle and hindlimb." | An alvarezsaurid. | Kol ghuva Shuvuuia deserti |
| Undescribed Alvarezsauridae | Indeterminate | Gilvent Wash | Not given. | An alvarezsaurid. | Kol ghuva Shuvuuia deserti |

##### Birds

| Genus | Species | Location | Material | Notes |
| Apsaravis | A. ukhaana | Ukhaa Tolgod | "Partial postcranial skeleton." | A basal ornithurine bird. |
| Elsornis | E. keni | Tugriken Shireh | "Partial articulated skeleton lacking the skull." | An enantiornithe. |
| Gobipteryx | G. minuta | Ukhaa Tolgod | "Partial skull." | An enantiornithine. Also present in the Barun Goyot Formation. |
| Protoceratopsidovum | P. fluxuosum | Bayn Dzak | "Partial eggs." | Eggs probably laid by a bird. |
| Protoceratopsidovum | P. minimum | Baga Tariach, Tugriken Shireh | "Clutch of four eggs and one pole of egg." | Eggs probably laid by a bird. |
| Protoceratopsidovum | P. sincerum | Bayn Dzak, Tugriken Shireh | "Multiple eggs and shells." | Eggs probably laid by a bird. |
| Styloolithus | S. sabathi | Bayn Dzak | "Partial to complete eggs." | Eggs probably laid by a bird. |

##### Dromaeosaurs

| Genus | Species | Location | Material | Notes |
| Halszkaraptor | H. escuilliei | Ukhaa Tolgod | "Partial skeleton with complete skull." | A halszkaraptorine. |
| Mahakala | M. omnogovae | Tugriken Shireh | "Fragmented skull and skeleton." | A halszkaraptorine. |
| Tsaagan | T. mangas | Ukhaa Tolgod | "Skull and partial skeleton." | A dromaeosaurid |
| Velociraptor | V. mongoliensis | Bayn Dzak, Chimney Buttes, Gilvent Wash, Tugriken Shireh, Udyn Sayr, Ukhaa Tolgod | "Multiple partial to complete specimens." | A dromaeosaurid. |
| Undescribed Dromaeosauridae | Indeterminate | Abdrant Nuru | "Claw." | A dromaeosaurid. |
| Undescribed Dromaeosauridae | Indeterminate | Zos Wash | "Frontal region." | A dromaeosaurid. Differs from Tsaagan. |

##### Non-maniraptoran theropods

| Genus | Species | Location | Material | Notes |
| Aepyornithomimus | A. tugrikinensis | Tugriken Shireh | "Nearly complete foot." | An ornithomimid. |
| Ornithomimosauria indet. | Indeterminate | Ukhaa Tolgod | "Partial braincase, jaw tips, ribs, and vertebral fragments". | An ornithomimid. |
| Tyrannosauridae indet. | Indeterminate | Bayn Dzak | Not specified. | A tyrannosaurid. |
| Tyrannosauridae indet. | Indeterminate | Khongil | "Supraorbital, vertebra, rib, femur and metatarsals." | A tyrannosaurid. |
| Tyrannosauridae indet. | Indeterminate | Not specified. | "Partial right ilium." | A tyrannosaurid. |
| Tyrannosauridae indet. | Indeterminate | Not specified. | "Teeth." | A tyrannosaurid. |

##### Oviraptorosaurs

| Genus | Species | Location | Material | Notes |
| Avimimus | A. portentonsus | Udyn Sayr | "Partial skull and skeleton." | An avimimid. Its locality origin has been disputed and may hail from the Nemegt Formation. |
| Citipati | C. osmolskae | Ukhaa Tolgod | "Multiple specimens with partial to nearly complete skeletons, an embryo, eggs and nesting individuals." | An oviraptorid. |
| Elongatoolithus | E. frustrabilis | | | |
| Elongatoolithus | E. subtitectorius | | | |
| Khaan | K. mckennai | Ukhaa Tolgod | "Several specimens with partial to complete skeletons and skulls." | An oviraptorid. |
| Macroolithus | M. mutabilis | | "Eggs." | Eggs probably laid by an oviraptorid |
| Oviraptor | O. philoceratops | Bayn Dzak | "Partial skeleton with skull, associated with a nest and juvenile." | An oviraptorid. |
| Oviraptoridae indet. | Indeterminate | Zamyn Khondt | "Nearly complete skeleton with skull." | An oviraptorid also known as the Zamyn Khondt oviraptorid. Uncertainly referred to Citipati. |
| Oviraptoridae indet. | Indeterminate | Zamyn Khondt | "Nearly complete skull with atlas and axis." | An oviraptorid. |
| Oviraptoridae indet. | Indeterminate | Udyn Sayr | "Assemblage of individuals." | An oviraptorid. |
| Oviraptoridae indet. | Indeterminate | Not specified. | "Two skulls with characteristic high crest." | An oviraptorid. |

##### Troodontids

| Genus | Species | Location | Material | Notes |
| Almas | A. ukhaa | Ukhaa Tolgod | "Skull with partial skeleton." | A troodontid. |
| Archaeornithoides | A. deinosauriscus | Bayn Dzak | "Partial skull." | A troodontid? Uncertain relationships among coelurosaurs. |
| Byronosaurus | B. jaffei | Ukhaa Tolgod | "Skull and fragmentary skeleton." | A troodontid. |
| Gobivenator | G. mongoliensis | Zamyn Khondt | "Almost complete skeleton." | A troodontid. |
| Saurornithoides | S. mongoliensis | Bayn Dzak | "Skull with fragmentary skeleton." | A troodontid. |
| Troodontidae indet. | Indeterminate | Ukhaa Tolgod | "Partial skeleton." | A troodontid. |
| Troodontidae indet. | Indeterminate | Ukhaa Tolgod | "Juvenile skulls, skeleton, and one nest." | A troodontid. Referred to either Almas, or Byronosaurus. |
| Troodontidae indet. | Indeterminate | Ukhaa Tolgod | "Fragmented skull and skeleton remains." | A troodontid. Provisionally referred to Saurornithoides, but now excluded. |
| Troodontidae indet. | Indeterminate | Ukhaa Tolgod | "Partial skull and skeletons from two specimens." | A troodontid. |

## Flora

| Genus | Species | Location | Material | Notes | Images |
| Radicites | R. gobiensis | Bayn Dzak | "Twenty plant roots." | A tracheophyte, likely conifer. | |