A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Appendix

Xenotarsosaurus
Taxon: Theropoda
Name means: “strange ankle lizard”
Pronounced: zen-o-TAR-so-SAWR-us
Length: Medium
Time: Late Cretaceous, c. 83 – 73 mya
Place: Argentina

This poorly-known carnivore was named in 1986 for its oddly fused ankle bones. These fossilized leg elements suggest that Xenotarsosaurus was not a very fast runner. Perhaps it scavenged rather than chasing down prey.

Xiaosaurus
Taxon: Ornithischia
Name means: “small lizard” or “dawn lizard”
Pronounced: ????
Length: 3 ft (1 m)
Time: Middle Jurassic, 169 – 164 mya
Place: China

This small, poorly-known plant-eater, based on teeth and a few other skeletal fragments, is not generally considered to be a valid genus. Xiaosaurus was named in 1983.

Xuanhanosaurus
Taxon: Theropoda
Name means: “Xuanhan lizard,” after Xuanhan County
Pronounced: SHWEN-HAHN-o-SAWR-us
Length: 20 ft (6 m)
Time: Middle to Late Jurassic, 175 – 163 mya
Place: China

This primitive carnivore had long and powerful forelimbs. It has been suggested, but is not widely believed, that Xuanhanosaurus may have been quadrupedal, walking on all four legs. The genus was named in 1984.