Abstract
The Pseudoplagioporinae n. subf. (Opecoelidae) is proposed for species of Pseudoplagioporus Yamaguti, 1938, Fairfaxia Cribb, 1989, and Shimazuia Cribb, 2005, a small group of relatively distinctive, Indo-West Pacific taxa reliably known almost entirely from emperor fishes (Perciformes: Lethrinidae). These taxa were previously recognized in the Plagioporinae Manter, 1947, but that subfamily has recently been restricted to a clade of Holarctic, freshwater taxa, whereas analyses of new genetic data find the pseudoplagioporines to form a distinct clade among a larger assemblage of marine taxa. New material was sourced from fishes collected mainly in Queensland waters, Australia, but with some specimens from off Western Australia, the Northern Territory, and Japan. Orthodena tropica Durio & Manter, 1968 is transferred to Pseudoplagioporus as P. tropicus (Durio & Manter, 1968) n. comb., and Orthodena Durio & Manter, 1968 thus becomes a synonym of that genus. Three new species of Pseudoplagioporus are proposed. One, P. mediocris n. sp., like other species of Pseudoplagioporus, occurs in several species of Lethrinus. The other two new species, P. labiatus n. sp. and P. roseovulatus n. sp., apparently do not infect species of Lethrinus and were instead found only in the Bigeye emperor Monotaxis grandoculis (Forsskal) and the Redfin emperor M. heterodon (Bleeker), respectively. New host-locality combinations and the first genetic data, for the ribosomal ITS2 DNA region, and the 28S rRNA, 18S rRNA, and cox1 mtDNA genes, are reported for Pseudoplagioporus lethrini Yamaguti, 1938, P. interruptus Durio & Manter, 1968, P. tropicus, Fairfaxia lethrini Cribb, 1989, Fairfaxia cribbi Hassanine & Gibson, 2005, and Shimazuia lethrini (Yamaguti, 1938) Cribb, 2005.
