Length 40 cm approx. Height of head 24 cm approx. (1:100 scale). FUN FACTS: Mamenchisaurus which was an impressive version of Chinas huge csauropod Mamenchisaurus that lived 160 to 145 million years ago. Known for its remarkably long neck which made up half the total body length, the various species of Mamenchisaurus may have reached between 22 m (72 ft) to 35 m (115 ft) in length. Uniquely the CollectA model incorporates a tail club suggested by unusual and fused vertebrae found at the tip of the tail of one fossil specimen.