Genus
Valid Extinct

Segnosaurus

Perle 1979
Etymology reptile lent

Segnosaurus is a genus of therizinosaurid dinosaur that lived in what is now southeastern Mongolia during the Late Cretaceous, about 102–86 million years ago. Multiple incomplete but well-preserved specimens were discovered in the Gobi Desert in the 1970s, and in 1979 the genus and species Segnosaurus galbinensis were named. The generic name Segnosaurus means "slow lizard" and the specific name galbinensis refers to the Galbin region. The known material of this dinosaur includes the lower jaw, neck and tail vertebrae, the pelvis, shoulder girdle, and limb bones. Parts of the specimens have gone missing or become damaged since they were collected. Remains from Japan originally assigned to Allosaurus were reassigned to Segnosaurus sp. in 2025.

Temporal range
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
252 201 145 66 0 Ma
PBDB occurrences
6
Group
Dinosaures
Herbivore Ground dwelling Terrestrial
Segnosaurus
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Wikimedia
PBDB Wikipedia
Classification
Dinosauria Unranked clade
Theropoda Unranked clade
Neotheropoda Unranked clade
Averostra Unranked clade
Tetanurae Unranked clade
Coelurosauria Unranked clade
Maniraptoriformes Unranked clade
Therizinosauria Unranked clade
Therizinosauroidea Superfamily
Therizinosauridae Family
Segnosaurus Genus
Measurements
Length
6,9 m
Segnosaurus galbinensis 
4 m
Mass
2 000 kg
Segnosaurus galbinensis 
1 300 kg
Fossil sites 6 geolocated sites
Distribution
Top countries
🇲🇳 Mongolia
4
🇯🇵 Japan
2
Geological formations
Jobu
2
Temporal distribution
Coniacian (89.8–85.7 Ma)
1
Turonian (93.9–89.8 Ma)
3
Cenomanian (100.5–93.9 Ma)
2
Species (1)
Segnosaurus galbinensis 101 Ma
Bibliography
Original description
A. Perle. 1979. Segnosauridae - novoe semeistvo teropod is posdnego mela Mongolii [Segnosauridae - a new family of theropods from the Late Cretaceous of Mongolia]. Trudy - Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya 8:45-55
Bibliography (4)
A. Burigo and O. Mateus. 2024. Allosaurus europaeus (Theropoda: Allosauroidea) revisited and taxonomy of the genus. Diversity 17(1):29:1-60 DOI ↗
L. E. Zanno. 2010. A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora). Journal of Systematic Palaeontology 8(4):503-543 DOI ↗
R. Barsbold. 1983. Khishchnye dinosavry mela Mongoliy [Carnivorous dinosaurs from the Cretaceous of Mongolia]. Transactions of the Joint Soviet-Mongolian Paleontological Expedition 19:1-117
A. Perle. 1979. Segnosauridae - novoe semeistvo teropod is posdnego mela Mongolii [Segnosauridae - a new family of theropods from the Late Cretaceous of Mongolia]. Trudy - Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya 8:45-55