I really like this deviation. Like "Triceratops", it reminds me of Sibbick's many large, green, front-facing ceratopsians.
Sibbick's "Normanpedia" Triceratops: https://2.bp.blogspot.com/-fCNZw7qDzBw/T94uVESk7xI/AAAAAAAAA8U/WbHsPgxsP9w/s1600/Cover.jpg
Sibbick's "When Dinosaurs Ruled the Earth" Triceratops: http://www.bibdsl.co.uk/imagegallery/bds/200443/9781840924565.JPG
Sibbick's "Creatures of Long Ago: Dinosaurs" Chasmosaurus: https://3.bp.blogspot.com/-kjeVHVb-E0M/UL0XY1Iw0bI/AAAAAAAABwM/8QdfPEWjGcE/s1600/Cover.jpg