New records of <I>Philopterus</I> (Ischnocera: Philopteridae) from Acrocephalidae and Locustellidae, with description of one new species from Regulidae

One species of the louse genus Philopterus Nitzsch, 1818 is redescribed and illustrated: Philopterus acrocephalus Carriker, 1949 ex Acrocephalus luscinius (Quoy & Gaimard, 1830), A. melanopogon (Temminck, 1823), A. scirpaceus (Hermann, 1804), A. schoenobaenus (Linnaeus, 1758), Iduna aedon rufescens Stegmann, 1929, I. rama (Sykes, 1832), Locustella sp. and L. ochotensis (von Middendorff, 1853). Philopterus acrocephalus represents the first species of the Philopterus-complex recorded in the family Locustellidae Bonaparte, 1854. Philopterus gustafssoni sp. nov. is described ex Regulus regulus (Linnaeus, 1758), R. regulus regulus (Linnaeus, 1758), R. regulus azoricus Seebohm, 1883, R. regulus buturlini von Loudon, 1911, R. regulus sanctaemariae Vaurie, 1954, R. regulus tristis Pleske, 1892 and R. ignicapillus (Temminck, 1820). Descriptions of both species are amended with genetic data, DNA sequences of mitochondrial cytochrome oxidase I, nuclear hyp and TMEDE6; concatenated sequences are compared to the morphologically nearest species with genetic data available, Philopterus citrinellae (Schrank, 1776) and Philopterus fringillae (Scopoli, 1772). Holotype of Philopterus reguli (Denny, 1842) is pronounced to be a straggler, determination of other known material from Regulidae is changed for Philopterus gustafssoni sp. nov.