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- XampylodonXampylodon is an extinct genus of cow shark. Fossils assigned to this genus are known from
- XanthogalerucaXanthogaleruca is a genus of beetles belonging to the family Chrysomelidae. These elm leaf
- XenacoelomorphaPhylum of animals
- XenambulacrariaXenambulacraria is a proposed clade of animals with bilateral symmetry as an embryo, consi
- XenarthraSuperorder of mammals including anteaters, sloths, and armadillos
- XenopeltisGenus of snakes
- Xenopeltis unicolorXenopeltis unicolor, commonly known as the sunbeam snake, common sunbeam snake or iridesce
- XenopusGenus of amphibians
- XeriniTribe of rodents
- XerocoleA xerocole (from Greek xēros 'dry' and Latin col(ere) 'to inhabit'), is a general term ref
- XestobiumXestobium is a genus of death-watch and spider beetles in the family Ptinidae. There are a
- XilousuchusXilousuchus is an extinct genus of poposauroid from lower Triassic (Olenekian stage) depos
- XinjiangovenatorXinjiangovenator (meaning "Xinjiang hunter") is a genus of coelurosaurian dinosaurs, possi
- XiphactinusExtinct genus of ray-finned fishes
- XuanhanosaurusXuanhanosaurus (meaning "Xuanhan lizard") is a genus of theropod dinosaur that lived durin
- XyleboriniTribe of beetles
- Xyleborus (beetle)Xyleborus is by far the largest ambrosia beetle genus in the tribe Xyleborini, with over 5