Helminth parasites from Red Sea fishes: Neowardula brayi gen. nov., sp. nov. (Trematoda: Mesometridae Poche, 1926) and Sclerocollum saudii sp. nov. (Acanthocephala: Cavisomidae Meyer, 1932) Author Al-Jahdali, Mohammed O. text Zootaxa 2010 2681 57 65 journal article 10.5281/zenodo.199330 96e80d1f-e569-4069-bd45-a28029a08aa1 1175-5326 199330 Family: Mesometridae Poche, 1926 Mesometridae Poche, 1926 is a small trematode family, parasitizing the digestive tract of marine teleost fishes. Historically, the systematic position and relationships of this family have long been in dispute (see Szidat 1936 ; Skrjabin 1949 ; Jousson et al. 1957; Holliman 1961 ; Yamaguti 1971 ; Bray 1984 ; Brooks et al. 1985 ; Pearson 1992 ; Cribb et al. 2003 ; Olson et al. 2003). In this family, the tegument is spined, the anterior region of the ventral surface or all of it, is concave, acting as an accessory attachment organ since the mucosal surface of the host is smooth ( Bartoli 1987 ), the oral sucker is absent (see Hall and Cribb 2000 ; Cribb et al. 2001; Jones and Blair 2005 ), the ventral sucker is absent, the cirrus sac is absent and the excretory system is reticular. Jones and Blair (2005) comprehensively reviewed the family, recognizing 5 genera as valid within the family; Mesometra Luhe, 1901 , Centroderma Luhe, 1901 , Wardula Poche, 1926 , Elstia Bray, 1984 and Parawardula Jones et Blair, 2005 . These genera are easily distinguished from each other by the professional keys given by Jones and Blair (2005) . To date, no other genera are added and the 5 known genera comprise about 8 species.