Dodatak:Popis prakliještara, X
Xa uredi
†Xaniopyramis Siveter & Selden, 1987 uredi
- Xaniopyramis linseyi Siveter and Selden, 1987[1]
Animalia → Arthropoda → Merostomata → Xiphosurida → Moravuridae
Xi uredi
Rod Xiphosura Gronovius, 1764 uredi
- Sinonim = Limulus O.F. Müller, 1785
Razred Xiphosura Latreille, 1802 uredi
- sinonim = Merostomata Woodward, 1866
Red Xiphosurida R. & E. Richter, 1924 uredi
- Limulidae Leach, 1819