The identity of Nirmus obtusus and other Quadraceps species (Phthiraptera: Philopteridae) from Clipperton Island and the Galàpagos Islands

The identity of Nirmus obtusus Kellogg & Kuwana, 1902 is clarified based on the examination of its holotype, relavent literature and other lice samples from several species of other Charadriiform birds. The host louse association between N. obtusus and its type host (Sterna fuscata crissalis (Lawrence, 1872)) is discussed and deduced to be erroneous. The birds Tringa incana (Gmelin, 1789) and Tringa totanus (Linnaeus, 1758) are regarded as regular hosts for N. obustus, and evidence is presented supporting the opinion that T. incanas was the original natural host for the holotype of N. obtusus. The present status for this louse species is Quadraceps obustus (Kellogg & Kuwana, 1902); Degeeriella conformis Blagoveshtchensky, 1940 is regarded as the junior synonym (new synonym). Specimens of five other species of Quadraceps including Kellogg & Kuwana's material are compared with Q. obustus and discussed in relation to their hosts and locality records.