[F] Baynshirenskaya Svita - Bayn Shireh Formation - Sheeregeen Gashoon Formation - Mongolia
Mongolia
Barsbold 1983 The composition of these complex deposits was established recently. It includes segnosaurids (Segnosaurus and Erlicosaurus), dromaeosaurids, ornithomimids, and garudimimids. Ornithomimids (Archaeornithomimus) and tyrannosaurids (Alectrosaurus) are found beyond the borders of the country, near the southeastern border in the Iren Dabasu locality.
The most specific of the complex, segnosaurids, are known so far only from this horizon in the southeast of the country. Dromaeosaurids are represented by the \\\"highskulled\\\" lineage, distributed among other complexes in Mongolia as well as in the Late Cretaceous of North America.
Garudimimus is very interesting among the ornithomimids as the first truly primitive representative of the family. The second representative of the group is from the advanced lineage. The remains of Alectrosaurus have been found repeatedly in the southeast of the country, not only providing the possibility to more clearly refine its position among later carnosaurs, but also to determine the importance of including Archaeornithomimus in the composition of the studied complex, one of the first discoveries of these theropods beyond the borders of North America.
Archaeornithomimus was regarded as more primitive relative to the North American forms (Russell, 1972), however at that time the features of truly primitive ornithomimosaurs were not as well known as they are now thanks to the example of garudimimids. Archaeornithomimus is a rather typical representative of the advanced lineage in general, but it is not as developed as the more advanced Mongolian and North American forms in a series of features.
The theropod fauna of the Baynshirenskaya horizon is peculiar to the region in many features, and does not have a true analog either within or beyond the borders of the country. The presence of such widely distributed forms as dromaeosaurids in no way disguises the unique nature of the horizon, defined primarily by its segnosaurids. In the same manner, a great importance belongs to the ornithomimosaurs. Representatives of their advanced lineage bear greater similarity with end-Cretaceous North American types than with Mongolian forms.
The discovery of Alectrosaurus provided a basis for comparing this horizon with the Iren Dabasu Formation, even before it was isolated by the Central Asiatic Expedition (Gilmore, 1933; Morris, 1936). The forms reported from the Baynshirenskaya horizon are from a series of large localities on the southeast border: Khara Khutul, the Tariach region, Mongoin Bulak, Bayshin Tsia, Amtgai, Urilbe, etc.
The deposits in the section from the Shiregin Hashun locality can be [assigned] to the southwest horizons. Different authors establish the age correlation of the horizon with a considerable degree of conditionality. Above the faunal deposits of the Baynshirenskaya horizon lay the thicknesses of the Dzhavkhlantskaya Svita, the age of which remains unclarified and, in this case, based on the stratigraphic information belonging to the Baynshirenskaya Svita.
The correlation of the Dzhavkhlantskaya Svita with the [compromising] Djadokhtaskaya horizon is taken as highly conditional.
Achillobator giganticus - Burkhant - Coelurosauria Dromaeosauridae - Cretaceous Late Santonian Campanian
Albertosaurus (Alectrosaurus) olseni - Omnogov - Tyrannosaurinae Albertosaurini - Cretaceous Late ?Cenomanian Turonian Coniacian Santonian Campanian ? Maastrichtian
Alectrosaurus olseni (1) - Omnogov - Tyrannosauridae Aublysodontinae - Cretaceous Late ?Cenomanian Turonian Coniacian Santonian Campanian ? Maastrichtian
Alectrosaurus olseni (2) - Omnogov - Not considered dinosaur - Cretaceous Late ?Cenomanian Turonian Coniacian Santonian Campanian ? Maastrichtian
Alectrosaurus olseni (3) - Omnogov - Not considered dinosaur - Cretaceous Late ?Cenomanian Turonian Coniacian Santonian Campanian ? Maastrichtian
Amtocephale gobiensis - Pachycephalosauria Pachycephalosauridae - Cretaceous Late Turonian Coniacian Santonian
Amtosaurus magnus - Omnogov - Ornithischia indet. Nomina Dubia - Cretaceous Late Cenomanian Turonian
Enigmosaurus mongoliensis - Dornogov - Therizinosauroidea Therizinosauridae - Cretaceous Late Turonian Coniacian Santonian Campanian
Erlikosaurus andrewsi - Omnogov - Therizinosauroidea Therizinosauridae - Cretaceous Late Cenomanian Turonian
Gallimimus mongoliensis - Bayshin Tsav - Ornithomimidae Nomina Dubia - Cretaceous Late
Garudimimus brevipes - Omnogov - Ornithomimosauria Garudimimidae - Cretaceous Late Cenomanian Turonian
Graciliceratops mongoliensis - Omnogov; Sheeregeen Gashoon Formation - Neoceratopia Protoceratopidae - Cretaceous Late ?Santonian Campanian Maastrichtian
Maleevus disparoserratus - Omnogov; Sheeregeen Gashoon Formation - Ankylosauria Ankylosauridae - Cretaceous Late Cenomanian Turonian
Microceratops gobiensis - Omnogov; Sheeregeen Gashoon Formation - Ceratopia Neoceratopia - Cretaceous Late ?Santonian Campanian Maastrichtian
Segnosaurus galbinensis - Omnogov; Dornogov - Therizinosauroidea ?Therizinosauridae - Cretaceous Late Cenomanian Turonian
Talarurus plicatospineus - Omnogov; Dornogov - Ankylosauria Ankylosauridae - Cretaceous Late Cenomanian Turonian
Therizinosaurus cheloniformis - Omnogov; Dornogov - Therizinosauroidea Therizinosauridae - Cretaceous Late ?Campanian Maastrichtian
Tsagantegia longicranialis - Tsagan Teg (\\\"White Mountain\\\") locality - Ankylosauria Ankylosauridae - Cretaceous Late Cenomanian Turonian
Hadrosaurid indet - Omnogov - Ornithopoda Hadrosauridae - Cretaceous Late Cenomanian Turonian
Hadrosaurid indet. - Dornogov - Ornithopoda - Cretaceous Late Cenomanian Turonian
Theropoda indet. - Dornogov - Theropoda - Cretaceous Late Cenomanian Turonian
Hadrosaurid indet. - Omnogov; Sheeregeen Gashoon Formation - Ornithopoda - Cretaceous Late Cenomanian Turonian
Ornithomimid indet. - Omnogov; Sheeregeen Gashoon Formation - Theropoda - Cretaceous Late Cenomanian Turonian
Theropoda indet. - Omnogov; Sheeregeen Gashoon Formation - Theropoda - Cretaceous Late Cenomanian Turonian