| Bagaraatan | |
|---|---|
 | |
| Lower jaw bones | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Tyrannosauroidea |
| Clade: | †Pantyrannosauria |
| Genus: | †Bagaraatan Osmólska, 1996 |
| Type species | |
| †Bagaraatan ostromi Osmólska, 1996 | |
Bagaraatan (/'ba-ɣa-raa-tan/ meaning 'small'baɣa + 'carnivorous animal, beast of prey'araatan in Mongolian) is agenus oftheropoddinosaur from the LateCretaceous period of what is now theNemegt Formation ofMongolia. It may have been a small predatory dinosaur measuring around 3 to 4 metres (9.8 to 13.1 ft) in length.
Thetype species,B. ostromi, wasdescribed byHalszka Osmólska in 1996. Initially, the post-cranial (ZPAL MgD-I/108) skeleton had been described as "bird-like", while the skull was noted to exhibit features of several different theropod groups.
The material that warranted this conclusion was later found to be a chimaera of two non-avian dinosaurs, with some of the post-crania (hand bones, left femur, tibiotarsus, and rib) being referred to an indeterminatecaenagnathid, possiblyElmisaurus. The material that is considered the holotype, which includes the mandible, axial skeleton, pelvis, and one pedal phalanx, likely indicates thatBagaraatan is an indeterminatetyrannosaurid. Similarities between the material and young specimens ofTyrannosaurus andTarbosaurus indicate that the holotype represents a juvenile tyrannosaurid, one of the smallest currently known.[1]
Holtz classifiedBagaraatan as a basaltyrannosauroid, Coria identified it as atroodontid, and Rauhut placed it inManiraptora.[2]Mark Loewenet al. placed it inbasal Tyrannosauroidea, agreeing with the placement by Holtz.[3]
Below is thecladogram by Loewenet al. in 2013.[3]
In their 2024 reassessment ofBagaraatan, Słowiak,Brusatte & Szczygielski determined that the initial material referred toBagaraatan is chimaeric. They suggested that the material recognized as the holotype can more confidently be identified as a member of theTyrannosauridae or a closely related tyrannosauroid. When tested in aphylogenetic analysis,Bagaraatan was recovered in apolytomy with derived tyrannosauroids within the Tyrannosauridae. However, they caution that its exact phylogenetic position remains uncertain since juvenile specimens tend to be recovered in more basal positions than adults of the same species. Their results are shown in the cladogram below:[1]
Media related toBagaraatan at Wikimedia Commons
Data related toBagaraatan at Wikispecies
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