Anacanthorus cururutuiensis, Santos Neto & Muriel-Cunha & Domingues, 2019

Santos Neto, João F., Muriel-Cunha, Janice & Domingues, Marcus V., 2019, New species of Anacanthorus (Dactylogyridae: Anacanthorinae) from the gills of Hoplerythrinus unitaeniatus and Erythrinus erythrinus (Characiformes: Erythrinidae) of the coastal drainage in the Eastern Amazon, Brazil, Zootaxa 4615 (2), pp. 303-320 : 312-313

Anacanthorus cururutuiensis sp. n.

( Figs. 20–22 )

Type-host: Hoplerythrinus unitaeniatus (Spix & Agassiz) , Erythrinidae .

Site of infection: Gills.

Type-locality: Igarapé Cururutuia—Caeté River, municipality of Bragança, State of Pará, Brazil (1°4’44.55”S 46°44’18.54”W).

Other localities: Hoplerythrinus unitaeniatus (Prevalence: 66% of three hosts examined; Mean intensity: three parasites per host infected), Igarapé Arinandeua—Guamá River, municipality of São Miguel do Guamá, Pará State (1°37’42.50”S 47°29’45.06”W).

Prevalence: 100% of one host examined.

Mean intensity: 3 parasites per host infected.

Specimens deposited: Holotype: CHIOC no. 40030 a. 2 paratypes: CHIOC nos. 40030 b–c. 4 vouchers: INPA no. 804; MPEG nos. 157–158.

ZooBank registration: The Life Science Identifier (LSID) urn:lsid:zoobank.org:act:3D204F37-2579-48CE-9BC0-3617F4ADD7E4 .

Etymology: The specific epithet alludes to the affluent river’s name of the type locality of the species, Igarapé Cururutuia.

Comparative measurements: Table 5.

Description: (Based on four specimens, three mounted in Hoyer’s, one mounted in Gomori trichrome). Body fusiform 450 (423–489; n=3) long, excluding the haptor, 124 (95–151; n=3) wide at the height of germarium. Four cephalic lobes developed; three groups of head organs; cephalic glands not observed. Two pairs of ocelli; anterior pair smaller than posterior pair; accessory granules absent. Pharynx spherical 41 (39–44; n=3) long, 40 (36–44; n=3) wide; short esophagus. Two intestinal caeca, confluent, posteriorly. Genital pore not observed. MCO 42 (36–49; n=3) long, sclerotized, tubular, with distal region wider than the proximal region, and flexed lateral flap in the distal region of the MCO ( Fig. 20 ); accessory piece absent ( Fig. 20 ). Seminal vesicle, prostatic reservoir, and gonads not observed. Peduncle elongated. Haptor sub-hexagonal 39 (30–42; n=3) long, 72 (54–87; n=3) wide. Similar 4A hooks, with proximal dilatation comprising ½ of the hook length 9 (9–10; n=9) long ( Fig. 21 ). Seven pairs of similar hooks 17 (17–18; n=2) long, blade slightly curved; shank with proximal dilatation comprising approximately ¼ of the shank length, shank dilatation 4 (n=1) long; point short and curved, thumb erect and slightly truncated ( Fig. 22 ). Hook filament delicate, extending more than the half of the shank length ( Fig. 22 ).

Remarks: Anacanthorus cururutuiensis sp. n. differs from the remaining congeneric species based on the MCO morphology with distal region wider than the proximal region, and flexed lateral flap in the distal region, and for having hooks with proximal dilatation comprising ¼ of the shank length, and thumb erect and slightly truncated. Specimens of Anacanthorus were found parasitizing H. unitaeniatus of the Igarapé Arinandeua in São Miguel do Guamá, Pará State. The specimens are similar to Anacanthorus cururutuiensis sp. n. based on the MCO morphology, although with small morphological variation (i.e., the shank of the hook without evident proximal dilatation was observed in some specimens, and MCO without flexed lateral flap). However, the specimens do not have morphometric variations in comparison to the specimens of the type-locality (See Table 5). Thus, these morphological variations are considered here as intraspecific.

Figures

FIGURES 20–28. Anacanthorus cururutuiensis sp. n. 20. Male copulatory organ (MCO); 21. 4A hooks; 22. Hook; Anacanthorus acrophallus sp. n. 23. MCO; 24. 4A hooks; 25. Hook; Anacanthorus circumspatulatus sp. n. 26. MCO; 27. 4A hooks; 28. Hook. Fig. 20 scale of 25µm; Figs. 21–22 scale of 10µm; Figs. 23–25 scale of 10µm; Fig. 26 scale of 25µm; Figs. 27–28 scale of 10µm.