A new species of Anacanthoroides and redescription of Apedunculata discoidea (Monogenoidea) parasitizing Prochilodus argenteus (Actinopterygii) from the São Francisco River, Brazil Author Monteiro, Cassandra Moraes Author Brasil-Sato, Marilia Carvalho text Zootaxa 2014 3784 3 259 266 journal article 46108 10.11646/zootaxa.3784.3.5 f896588e-4b6b-4e6a-b383-740af8bfe7ec 1175-5326 230264 EE171329-9D0F-4255-A7B7-C1C1A0E1D4CD Anacanthoroides sanctifrancisci n. sp. ( Figs. 1–4 ) Type-host and locality. Prochilodus argenteus Spix & Agassiz , ( Prochilodontidae ), ‘curimatã-pacú’; São Francisco River, near Três Marias, State of Minas Gerais, Brazil ( 18º12’32”S ; 45º14’41”W ). Site. Gills filament. Specimens studied. Holotype , CHIOC 37914; 10 Paratypes CHIOC 37915, 37916 a–b, 37917, 37918 a–c, 37919, 37920 a–b. Etymology. The specific epithet “ sanctifrancisci ” refers to the São Francisco River, where the hosts were collected. FIGURES 1–4. Anacanthoroides sanctifrancisci n. sp. from ‘curimatã-pacú’, Prochilodus argenteus from the São Francisco River, Brazil, in ventral view. (1) Whole mount (composite). (2) Copulatory complex. (3) Hook. (4) Reduced hook. Scale = 150 µm (1) and 15 µm (2 – 4). Description. (Based on 11 specimens ). Body robust, 546 (289–950; n=5) long; greatest width 163 (120–280; n=6) at the pharyngeal region. Tegument thin and smooth. Cephalic lobes not developed; head organs poorly developed in the cephalic region. One pair of half-moon pseudosuckers in the ventral, anterior cephalic region. Four eyespots; members of posterior pair slightly apart, larger than those of anterior pair; chromatic granules small, oval to elliptic; without accessory granules scattered in the cephalic region. Oral opening halfway between the pseudosuckers and pharynx. Pharynx sub-spherical, 46 (38?57; n=4) in diameter; esophagus short. Peduncle broad, with width similar to haptor. Haptor sub-spherical, 118 (82?200; n=5) long, 110 (79?148; n=5) wide. Anchors and bars absent. Seven pairs of hooks, similar, sub-equal, 15 (15?17; n=12) long, with recurved point, inflated proximal; filamentous hook (FH) loop about shank length. One pair of central hooks reduced, 9 (8?10; n=5) long. Testes fusiform, 48 long; 33 wide; seminal vesicle oval to spherical. Male copulatory organ is a coil of 3?4 counterclockwise rings arising from a small base; proximal ring diameter 24 (17?31; n=3). Accessory piece not articulated to the male copulatory organ, serving as a guide for the distal portion of the male copulatory organ, 25 (24?28; n=4) long. Germarium fusiform, 62 (57?68; n=2) long, 32 (29?36; n=2) wide; oviduct large, strongly muscular, with one pair of distal projections; vaginal pore sinistral; seminal receptacle large, in the anterior region of the germarium. Vitelline follicles dense, coextensive with intestinal caeca; lateral bands of follicles confluent post-pharyngeal and posterior to the gonads; transverse vitelline duct immediately anterior to the germarium. Remarks. Anacanthoroides was originally proposed by Kritsky & Thatcher (1976) for A . mizellei from the gills of a prochilodontid fish. On that occasion, it was included in a group where the haptorial anchors were lacking with: Acolpenteron Fischthat & Allison, 1940 ; Anacanthorus Mizelle & Price, 1969; Anonchohaptor Mueller, 1938 ; Icelanonchohaptor Leiby, Kritsky & Peterson, 1972 and Pseudacolpenteron Bychowsky & Gussev, 1955 . Since the proposition, Anacanthoroides remains monotypic, but an undetermined species was recorded in the gills of P . lineatus in the Paraná River basin by Lizama et al . (2005). Anacanthoroides sanctifrancisci n. sp. was included in Anacanthoroides , monotypic, by the absence of bars and anchors in the haptor and the presence of a sinistromarginal vagina. The new species differs from the type and only species, A . mizellei , by: (1) the shape of the anterior region of the body; (2) the presence of a pair of muscular pseudosuckers in the anterior region of body; (3) the accessory piece not being articulated to the male copulatory organ; and (4) the MCO comprising a coil of 3?4 rings. Anacanthoroides was found to parasitize P . reticulatus and P . argenteus ; an investigation into the congeneric hosts may extend the records of previously known species to other hosts and localities or reveal as yet undescribed species.