Two new dactylogyrid species (Dactylogyroidea: Dactylogyridae), gill parasites of freshwater fishes from the Peruvian Amazon, including the proposal of Peruanella n. gen. Author Cruces, Celso L. Laboratorio de Genómica y Biología Evolutiva, Instituto de Ciencia y Tecnología, Universidad Ricardo Palma (URP), Avenida Alfredo Benavides 5440 Santiago de Surco, Lima 15039, Peru Author Santillán, Luis A. Laboratorio de Genómica y Biología Evolutiva, Instituto de Ciencia y Tecnología, Universidad Ricardo Palma (URP), Avenida Alfredo Benavides 5440 Santiago de Surco, Lima 15039, Peru & Laboratorio de Zoología de Invertebrados, Departamento Académico de Zoología, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos (UNMSM), Avenida Universitaria Cruce Con Avenida Venezuela Cuadra 34, Lima 15081, Peru Author Silvera, Jordan F. Laboratorio de Genómica y Biología Evolutiva, Instituto de Ciencia y Tecnología, Universidad Ricardo Palma (URP), Avenida Alfredo Benavides 5440 Santiago de Surco, Lima 15039, Peru & Laboratorio de Zoología de Invertebrados, Departamento Académico de Zoología, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos (UNMSM), Avenida Universitaria Cruce Con Avenida Venezuela Cuadra 34, Lima 15081, Peru Author Morey, Germán Augusto Murrieta Laboratorio de Parasitología y Sanidad Acuícola, Instituto de Investigaciones de la Amazonía Peruana (IIAP), Iquitos, Peru & Programa de Pós-Graduação em Ciência Animal (PPGCA), Universidade Estadual do Maranhão (UEMA), São Luís, Maranhão, Brazil Author Rubin, Veronica Laboratorio de Genómica y Biología Evolutiva, Instituto de Ciencia y Tecnología, Universidad Ricardo Palma (URP), Avenida Alfredo Benavides 5440 Santiago de Surco, Lima 15039, Peru Author Chero, Jhon D. Laboratorio de Genómica y Biología Evolutiva, Instituto de Ciencia y Tecnología, Universidad Ricardo Palma (URP), Avenida Alfredo Benavides 5440 Santiago de Surco, Lima 15039, Peru & Laboratorio de Zoología de Invertebrados, Departamento Académico de Zoología, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos (UNMSM), Avenida Universitaria Cruce Con Avenida Venezuela Cuadra 34, Lima 15081, Peru & Laboratorio de Genómica y Biología Evolutiva, Instituto de Ciencia y Tecnología, Universidad Ricardo Palma (URP), Avenida Alfredo Benavides 5440 Santiago de Surco, Lima 15039, Peru text Zootaxa 2024 2024-04-24 5443 4 591 600 http://dx.doi.org/10.11646/zootaxa.5443.4.7 journal article 10.11646/zootaxa.5443.4.7 1175-5326 11064545 BA496C70-3770-4E41-AF6F-935AAFAF5FFF Peruanella madredediosensis n. sp. ( Fig. 1A–G ) Type-host: Brachyplatystoma tigrinum (Britski) ( Siluriformes : Pimelodidae ). Site on host: Gill filaments. Type locality: Madre de Dios River ( 12°35’S , 69°10’W ), Puerto Maldonado City , Madre de Dios region , Peru . Type material: Holotype , MUSM-HEL 5390 ; 9 paratypes , MUSM-HEL 5391 a-i. Etymology: The specific name refers to the type locality. Description: Based on 10 specimens . Body elongate, fusiform ( Fig. 1A ), 920–1850 (1241; n = 10) long; greatest width 172–275 (214; n = 10) usually at level of ovary. Two bilateral cephalic lobes poorly developed. Three bilateral pairs of inconspicuous head organs; bilateral pair of cephalic glands at post-pharyngeal level. Eyes and accessory eyespot granules absent. Pharynx spherical, well developed, 77–119 (101; n = 10) in diameter, with accessory bulb. Group of well-developed secretory gland-cells lying on peduncle. Haptor sub-quadrangular ( Fig. 1A ), poorly differentiated from body proper, 61–95 (72; n = 10) long; 90–153 (118; n = 10) wide. Anchors with fine conspicuous alae, similar in shape and size, moderately developed roots, short and robust shaft, and elongated straight point; shaft and point with surface striations ( Fig. 1B, C ). Ventral anchor 26–36 (32; n = 10) long, base 6–9 (7; n = 10) wide. Dorsal anchor 29–35 (33; n = 9) long, base 6–9 (7; n = 9) wide. Ventral bar straight, elongated, with poorly-developed lateral wing-like expansions ( Fig. 1D ), 52–71 (65; n = 10) long. Dorsal bar almost slightly bent, grooved, with two inconspicuous anteromedial protuberances ( Fig. 1E ), 51–70 (64; n = 10) long. Hooks, 14–18 (16; n = 8) long, similar in shape and size, each with protruding and obtuse thumb, slender and curved shank, and short and recurved point; filamentous hook (FH) about shank length ( Fig. 1F ). Male copulatory organ (MCO) 99–122 (114; n = 10) long, tubular, almost J-shaped, slightly expanded sclerotized base, bent distal end ( Fig. 1G ). Accessory piece articulated to MCO base, curved, strongly sclerotized, kidney-shaped proximally, with a hook-shaped distal end ( Fig. 1G ), 75–109 (94; n = 10) long. Testis subspherical, 151–162 (157; n = 2) long, 102–111 (106; n = 2) wide; prostatic reservoir and prostatic glands not observed. Ovary ovate, 85–129 (111; n = 6) long, 81–150 (120; n = 6) wide; oviduct, oötype and uterus not observed. Vaginal aperture midventral; vaginal vestibule inconspicuous; vaginal duct narrow, short, running posteriorly to join conspicuous subspherical seminal receptacle ( Fig. 1A ). Eggs not observed. Remarks: Peruanella madredediosensis n. gen., n. sp. is the type species of the genus and can be easily distinguished from P . aureagarciae n. comb. by the presence of striations on the surface of the shaft and point of anchors, a feature absents in P . aureagarciae n. comb. Additionally, P . madredediosensis n. gen., n. sp. differs from P . aureagarciae n. comb. in terms of MCO morphology. In the former, the distal end of the MCO remains unexpanded, contrasting with the expanded nature observed in P . aureagarciae n. comb. Moreover, while the anchors of P . madredediosensis n. gen., n. sp. exhibit similarity in size, those of P . aureagarciae n. comb. present dissimilar sizes.