Beckwithia
Encyclopedia
Beckwithia is an extinct genus of Merostomata
characterised by a fused tail-plate. It contains one species, Beckwithia typa, although two other species have been ascribed to it (no tail plate is preserved in "Beckwithia major", and "Beckwithia daubikhensis" may be a poorly preserved Khankapsis bazhanovi). It is sometimes placed in a separate family, Beckwithiidae.
Merostomata
Merostomata is the name given to a grouping of the extinct Eurypterida and the Xiphosura . The term was originally used by James Dwight Dana to refer to Xiphosura only, but was emended by Henry Woodward to cover both groups....
characterised by a fused tail-plate. It contains one species, Beckwithia typa, although two other species have been ascribed to it (no tail plate is preserved in "Beckwithia major", and "Beckwithia daubikhensis" may be a poorly preserved Khankapsis bazhanovi). It is sometimes placed in a separate family, Beckwithiidae.