Both sexes of the enigmatic laophontid species Pseudonychocamptus carthyi Hamond, 1968 (Copepoda, Harpacticoida) are redescribed in detail based on type and other material from Norfolk, England. The species exhibits marked differences with other Pseudonychocamptus species and is consequently fixed as the type of a new genus Marbefia, gen. n., being defined by the following autapomorphies: (1) P2–P4 enp-2 (except P4 enp-2 in ♂) inflated, with two parallel rows of flimsy setular extensions; (2) P4 with sexually dimorphic setation on enp-2 (outer distal seta reduced in ♀, very long in ♂); and (3) antennule ♀ with spinules along posterior margins of segments 1–6. Laophonte danversae Hamond, 1969, “Laophontid male, ?gen., ?sp.” sensu Hamond (1969) [renamed as Inermiphonte hamondi, sp. n.] and... Laophonte ?drachi Médioni & Soyer, 1966 are collectively placed in a new genus Inermiphonte, gen. n. which shares as sistergroup relationship with Harrietella T. Scott, 1906. Marbefia, gen. n. is considered sister to a clade comprising the genera Pseudonychocamptus Lang, 1944, Pilifera Noodt, 1952, Inermiphonte, gen. n. and Harrietella. Pseudonychocamptus kolarovi Apostolov, 2008 is transferred to Paralaophonte whereas Chislenko’s (1967) record of P. koreni Sars, 1908a is considered doubtful. Willey’s (1935) variety “fissirostris” of Paralaophonte brevirostris (Claus, 1863) is rejected pending a thorough analysis of the variability in the P. brevirostris complex of species. P. congenera mediterranea Lang, 1948 appears to be more closely related to P. lacerdai Jakobi, 1953 than to its nominotypical subspecies P. congenera congenera (Sars, 1908b) whereas P. pacifica galapagoensis Mielke, 1981 (here upgraded to full specific rank) is more similar to P. brevirostris than to its nominotypical subspecies P. pacifica pacifica Lang, 1965. A new species, Paralaophonte pallaresae, sp. n. is proposed for P. gracilipes Brady, 1910 sensu Pallares (1968). The potentially paraphyletic status of the genus Paralaophonte is discussed. Dichotomous identification keys are provided for the valid species of Pseudonychocamptus Lang, 1944 and Paralaophonte Lang, 1948.