xiphosura การใช้

• The abdominal appendages of modern chelicerates are missing or heavily modified while those of horseshoe crabs ( Xiphosura ) form gills.
• The "'Xiphosura "'are an chelicerates that includes a large number of extinct lineages and only four extant species in the family Limulidae, which includes the horseshoe crabs.
• Xiphosura were traditionally placed in the class Merostomata, although this term was intended to encompass also the paraphyletic ) group ( although this is a grouping recovered in some recent cladistic analyses ).
• A recent summary of the relationships between arachnids and their relatives recognised Eurypterida, Xiphosura and Arachnida as three major groups, but was not able to resolve the phylogenetic relationship of any shared details between them.