Out of all the dinosaur groups, the therizinosaurs are perhaps the most unusual. While they are related to large, carnivorous predatory theropods such as the tyrannosaurs and dromaeosaurs, they are actually large, long-necked herbivores. They look very similar to prosauropods, except that therizinosaurs have very long claws on their three-fingered hands.
The therizinosaurs first evolved in the Early Cretaceous from small prosauropod-like browsers such as Beipiaosaurus and Falcarius. Their diversity was put to a halt by the Tithonian-Berriasian glaciation. As a result, the therizinosaurs stayed small for most of the Cretaceous in this alternate timeline. However, they did start to get larger during the Paleocene-Eocene Thermal Maximum thanks to there being lots of forests at the time. Despite this, at the end of the Eocene, the therizinosaurs started to decline due to the spread of the fern prairies. Their tall necks and long claws was perfect for eating from the treetops, but were much less effective at processing grass-like ferns than the ornithopods. As a result, most of the therizinosaurs retreated to the tropics, although one group did adapt to colder climates.
During the Miocene, one group of therizinosaurs migrated from Asia to Africa, and another group migrated from North to South America via the Isthmus of Panama during the Pliocene. Despite this, the therizinosaurs died out in most of North America during the Pleistocene. Today, most therizinosaurs are found in South America, southern Asia and Africa, although one cold-adapted group continues to thrive in Europe and northern Asia; one therizinosaur species still lives in North America.
Clawed Titans (Family: Megalotitanidae)Edit
These large therizinosaurs are found throughout Africa and Southern Asia. Clawed titans feed mostly on leaves although they'll also eat fruit. These therizinosaurs are also massive, measuring over 8 meters in length and over 10 meters tall. They use their very long claws for both feeding on the treetops and for defense against predators such as gigaraptors and false carnosaurs. Fossil evidence shows that their range once extended as far north as Europe and Siberia, but the clawed titans were probably outcompeted by snowclaws in Europe and Northern Asia. They are also restricted to a single genus, Titanonychus.
- West African Clawed Titan (Titanonychus occidentalis)
- East African Clawed Titan (Titanonychus orientalis)
- Indian Clawed Titan (Titanonychus indicus)
- Dwarf Clawed Titan (Titanonychus pygmaeo)
Snowclaws (Family: Polikosauridae)Edit
While most therizinosaurs are solitary browsers, snowclaws travel in small family groups to avoid both predators and the freezing cold weather of their Taiga habitat in Europe and Northern Asia. They are covered in a very thick coat of feathers for warmth. If the weather gets to cold, snowclaws will even seek refuge in ice caves for shelter against the cold. They first evolved in the Miocene when the climate started to get colder in Northern Eurasia.
- European Snowclaw (Chionatosaurus europaeus)
- Siberian Snowclaw (Chionatosaurus siberianus)
- Mongolian Snowclaw (Chionatosaurus mongoliensis)
- Far-Eastern Snowclaw (Chionatosaurus orientalem) (Found in Japan, Manchuria and Korea)
Jungleclaws (Family: Zounkladae)Edit
Tropiclaws are among the smallest therizinosaurs in this alternate timeline. However, they are still rather large at over 5 meters in length and over 8 meters tall. These therizinosaurs are native to South America and most species are found in the Amazon rainforest although they have spread out to the Andes, the Pampas and Patagonia. One species even managed to spread out to North America. The jungleclaws main predators are false carnosaurs, large dromeasaurs and large crocodilians.
- Andes Jungleclaw (Zounklanychus vouno)
- Pampas Jungleclaw (Zounklanychus leimos)
- Patagonian Jungleclaw (Zounklanychus patagonia)
- Dwarf Jungleclaw (Zounklanychus pygmaeo)
- Common Jungleclaw (Zounklanychus diadedomeni)
- North American Jungleclaw (Zounklanychus septentrionali)
|Sauropsida||Archosauria||Theropoda||Abelisauroidea • Aves • Dromaeosauridae • Gigaraptornae (Dinosaurs of the Ice Age) • Ornithomimosauria • Therizinosauria • Tyrannosauroidea|
|Ornithischia||Ankylosauria • Ceratopsia • Ornithopoda|
|Lepidosauromorpha||Plesiosauria • Squamata|
|Mammalia||Eutheria • Metatheria • Monotremata|