Peruanella madredediosensis, Cruces & Santillán & Silvera & Morey & Rubin & Chero, 2024

Cruces, Celso L., Santillán, Luis A., Silvera, Jordan F., Morey, Germán Augusto Murrieta, Rubin, Veronica & Chero, Jhon D., 2024, Two new dactylogyrid species (Dactylogyroidea: Dactylogyridae), gill parasites of freshwater fishes from the Peruvian Amazon, including the proposal of Peruanella n. gen., Zootaxa 5443 (4), pp. 591-600 : 594

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.

Figures

FIGURE 1. Peruanella madredediosensis n. sp. from Brachyplatystoma tigrinum (Britski) (Siluriformes: Pimelodidae). A. Whole mount (composite, ventral view). B. Ventral anchor. C. Dorsal anchor. D. Ventral bar. E. Dorsal bar. F. Hook. G. MCO. CA: conspicuous alae. VP: Vaginal aperture.