Anacanthoroides sanctifrancisci, Monteiro, Cassandra Moraes & Brasil-Sato, Marilia Carvalho, 2014

Monteiro, Cassandra Moraes & Brasil-Sato, Marilia Carvalho, 2014, A new species of Anacanthoroides and redescription of Apedunculata discoidea (Monogenoidea) parasitizing Prochilodus argenteus (Actinopterygii) from the São Francisco River, Brazil, Zootaxa 3784 (3), pp. 259-266 : 260-262

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.

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.

Figures

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).