A new Mexican species of the Cryptopygus complex (Collembola, Isotomidae) associated with the hermit crab Coenobita clypeatus (Crustacea, Coenobitidae)

A new species of Cryptopygus Willem, 1901 associated with hermit crabs living on seashores of Quintana Roo State, Mexico, is described and illustrated. It is blind, with 9–11 postlabial setae, unguis with a pair of lateral teeth, empodial appendix lanceolate and almost as long as unguis, tenaculum with 4 + 4 teeth and 3–4 setae on corpus, manubrium with 11–14 pairs of manubrial setae on anterior surface and 17–18 pairs on posterior surface, and mucro bidentate. An updated key for the identification of 29 American species of Cryptopygus complex is included.