Monogenoids (Polyonchoinea, Dactylogyridae) from Hydrolycus armatus (Characiformes, Cynodontidae) with the description of a new species of Rhinoxenus and the proposal of a new genus from the Xingu River, Pará, Brazil

One new species of Rhinoxenus Kritsky, Boeger & Thatcher, 1988 from the nasal cavities and four new species of Mymarothecioides n. gen. from the gills are described in Hydrolycus armatus (Jardine & Schomburgk). They were collected in the Xingu River, Pará, Brazil. Rhinoxenus cachorra n. sp. is characterized by having a ventral anchor with inconspicuous roots, and point with fish-hook-like termination; copulatory complex comprising a spiraled male copulatory organ (MCO) with two counterclockwise coils, and an accessory piece with an expanded, bifurcated distal portion. Mymarothecioides n. gen. is proposed and characterized for species without eyes, with or without accessory chromatic granules; copulatory complex comprising articulated MCO, accessory piece; MCO a broad arcuate tube; an accessory piece with a hooked termination in the distal portion; a dextro or midventral non-sclerotized vagina; an anteromedial projection on the ventral bar. Mymarothecium whittingtoni Kritsky, Boeger & Jégu, 1996 is transferred to Mymarothecioides n. gen. as Mymarothecioides whittingtoni (Kritsky, Boeger & Jégu, 1996) n. comb.

Monogenoidean parasites of Acestrorhynchus falcatus (Characiformes: Acestrorhynchidae) from Pará, Brazil: species of Diaphorocleidus and Rhinoxenoides n. gen. (Monogenoidea: Dactylogyridae)

Two new species of Diaphorocleidus and one new species of Rhinoxenoides n. gen. are described from the gills of Acestrorhynchus falcatus (Bloch) from rivers of north-eastern Pará, Brazil. Diaphorocleidus jaymedeloyolai n. sp. is characterized by a male copulatory organ (MCO) possessing three counterclockwise coils; similar anchors with subtriangular superficial roots; a ventral bar with posteromedial projection; and hooks of pairs 1, 4 and 7 approximately three times longer than hook pair 5. Diaphorocleidus sclerocolpus n. sp. differs from its congeners by a dual-branched accessory piece articulated with the MCO and a sclerotized tubular vagina with a bottle-shaped vestibule. Rhinoxenoides n. gen. is proposed and is characterized by possessing: MCO sclerotized with clockwise coils; an accessory piece articulated to the base of MCO; a sinistroventral vaginal aperture; ventral anchor with conspicuous roots; dorsal anchor with superficial root five times longer than deep root; and absence of dorsal bar. The proposal of Rhinoxenoides n. gen. is also supported by its phylogenetic relationship with Protorhinoxenus prochilodi and species of Rhinoxenus, using 16 morphological characters, which resulted in the following hypothesis of sister-group relationships: Rhinoxenoides n. gen. [Protorhinoxenus (Rhinoxenus curimatae (R. nyttus (R. bulbovaginatus (R. guianensis, R. piranhus, R. euryxenus (R. arietinus, R. anaclaudiae)))))].

Dactylogyrids (Platyhelminthes, Monogenoidea) from the gills of Hoplias malabaricus (Characiformes: Erythrinidae) from coastal rivers of the Oriental Amazon Basin: species of Urocleidoides and Constrictoanchoratus n. gen.

Five species of Urocleidoides (one new) and two new species of Constrictoanchoratus n. gen. are described in this study. All were collected from the gills of Hoplias malabaricus (Characiformes: Erythrinidae) captured in six localities of coastal rivers of the north-eastern sector the State of Pará (Oriental Amazon): Urocleidoides brasiliensis Rosim, Mendoza-Franco & Luque, 2011; Urocleidoides bulbophallus n. sp.; Urocleidoides cuiabai Rosim, Mendoza-Franco & Luque, 2011; Urocleidoides eremitus Kritsky, Thatcher & Boeger, 1986; Urocleidoides malabaricusi Rosim, Mendoza-Franco & Luque, 2011; Constrictoanchoratus lemmyi n. gen. n. sp.; and Constrictoanchoratus ptilonophallus n. gen. n. sp. This is the first reported occurrence of the four previously described species of Urocleidoides parasitizing H. malabaricus from streams in the Oriental Amazon Basin. The analysis of voucher specimens of U. eremitus parasitizing the gills of H. malabaricus from the Upper Paraná River floodplain in the limits of States of Paraná and Mato Grosso do Sul, Brazil, indicates that these specimens are members of a new species of Urocleidoides, described here as Urocleidoides paranae n. sp. Constrictoanchoratus n. gen. is proposed for the species with a male copulatory organ sclerotized, coiled, clockwise; ventral anchor with elongate superficial root, inconspicuous deep root; dorsal anchor with inconspicuous roots, and a constriction at the intersection between the shaft and the point. The host–parasite diversity scenario and host specificity of the species of Constrictoanchoratus n. gen. and Urocleidoides from the gills of H. malabaricus are also discussed in this study.

A description of two new species of Ligophorus Euzet & Suriano, (Monogenea: Ancyrocephalidae) from Malaysian mugilid fish using principal component analysis and numerical taxonomy

Ligophorus belanaki n. sp. and Ligophorus kederai n. sp. are described from Liza subviridis Valenciennes, 1836 and Valamugil buchanani Bleeker, 1854, respectively. Ligophorus kederai n. sp. has fenestrated ventral anchors, while in L. belanaki n. sp. the ventral anchor is not fenestrated. Ligophorus belanaki n. sp. is similar to L. careyensis, one of its coexisting congeners, in the overall shape and size of hard parts, but differs in having a flat median piece in the structure of the AMP (antero-median protuberance of the ventral bar), copulatory organ with non-ornamented initial part and longer vaginal tube, compared to raised median piece in the AMP, ornamented initial part and comparatively shorter vaginal tube in L. careyensis. Ligophorus kederai n. sp. is similar to L. fenestrum, a coexisting congener, in having fenestrated ventral anchors, but differs in having longer points and narrower base. Ligophorus fenestrum, unlike L. kederai n. sp., also possesses fenestrated dorsal anchors. The principal component analysis (PCA) scatterplots indicate that the two new and eight known Ligophorus species from Malaysian mugilids can be differentiated based on the morphometries of their anchors, ventral bars and copulatory organ separately and when combined together. Numerical taxonomy (NT) analyses based on Jaccard's Index of Similarity and neighbour-joining clustering, is used to facilitate comparison of these two new species with the 50 known Ligophorus based on morphological and metric characters. The two new species are different from each other and the other 50 species in the overall shapes and sizes of hard parts, as indicated by the NT analyses.

Neotropical Monogenoidea. 57. Nine new species of Dactylogyridae (Monogenoidea) from the gill of Salminus brasiliensis (Characidae, Characiformes) from the Paraná River, State of Paraná, Brazil

During a long-term study of the parasites of fishes from the Paraná River, both below and above the reservoir of the Itaipu Hydroelectric Power Station, State of Paraná, Brazil, specimens of 10 species of Dactylogyridae (9 new and one previously known) were collected from the gills of Salminus brasiliensis. The following species are described and illustrated: Anacanthorus douradensis sp. n., A. bicuspidatus sp. n., A. daulometrus sp. n., A. contortus sp. n., A. parakruidenieri sp. n., Annulotrematoides bryconi Cuglianna, Cordeiro and Luque, 2003, A. glossophallus sp. n., A. parisellei sp. n., Jainus iocensis sp. n. and Tereancistrum arcuatus sp. n. Anacanthorus douradensis sp. n. appears closely related to Anacanthorus colombianus by sharing a MCO composed of a loosely spiraled tube and an articulated and bifurcated accessory piece; the new species may be differentiated from A. colombianus by the bifurcation of the accessory piece at the proximal portion of the structure, the presence of subequal rami of the accessory piece, and by the number of coils in the MCO (6 in the new against 3 in the previously described species). Anacanthorus bicuspidatus sp. n. has great similarity to Anacanthorus cuticulovaginus but can be easily differentiated by presenting one of the rami hook shaped and with a subterminal thumb-like expansion and MCO more delicate and slender, distally pointed. Anacanthorus daulometrus sp. n. is similar to A. cuticulovaginus and A. biscuspidatus sp. n. but differs by presenting one of the branches of the accessory piece bifid and by the presence of a conspicuous metraterm with heavily sclerotized walls. Anacanthorus contortus sp. n. resembles A. quinqueramus in depicting an accessory piece composed by five branches; the new species differs from this species by an accessory piece composed of two main branches, one of them with 4 sub-branches. Anacanthorus parakruidenieri is morphologically similar to Anacanthorus kruidenieri; these species are easily distinguishable by the presence of a bifurcated accessory piece and a subcircular foramen in the shank bulb of the new species. Annulotrematoides glossophalllus sp. n. differs from the previously known species of the genus, A. amazonicus and A. bryconi, by a relatively more robust and slightly arcuate MCO with a distinctive tongue-shaped expansion at the distal opening and by the presence of the flap-like expansion near midlength of the accessory piece. Annulotrematoides parisellei sp. n. closely resembles A. bryconi and A. glossophallus from which it can be distinguished by the comparative morphology of the copulatory complex (arcuate and delicate in the new species and robust with a tongue-shape distal end in the other two species). The general morphology of the copulatory complex of A. parisellei sp. n. resembles that of A. amazonicus, but differs by the morphology of all haptoral sclerites, presenting both ventral and dorsal anchors with conspicuous points evenly curved with shafts. Jainus iocensis sp. n. resembles J. amazonensis by the morphology of anchors, differing from this species by having a large sclerotization on the superficial root of ventral anchor and by the shape of the accessory piece, which is hook-shaped in the new species and distally flabellate in J. amazonensis. Finally, Tereancistrum arcuatus sp. n. can be easily distinguished from the other species of the genus by the MCO, which is an arcuate tube, while the others present a coiled copulatory organ. The few specimens of Annulotrematoides bryconi collected from S. brasiliensis are in accordance with the general morphology and measurements of the original description and type specimens.