Merostomata (Merostomes) is a class of chelicerates. There are 8 species of Merostomes, in 10 genera and 10 families. It includes groups like Horseshoe Crabs And Relatives.
Definition: overall repetitive or reflective pattern in the body of one individual of this taxon. eg: bilateral symmetry, rotational symmetry, radial symmetry
Definition: number of currently described and taxonomically accepted marine species in this clade (Appeltans et al. 2012. The Magnitude of Global Marine Species Diversity. Current Biology 22, 2189–2202. http://dx.doi.org/10.1016/j.cub.2012.09.036)
Definition: "marine species in this clade which are currently represented in specimen collections (estimate) (Appeltans et al. 2012. The Magnitude of Global Marine Species Diversity. Current Biology 22, 2189–2202. http://dx.doi.org/10.1016/j.cub.2012.09.036)"