Anacanthorus siphonocommus, 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 : 306-308

Anacanthorus siphonocommus sp. n.

( Figs. 8–11 )

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: 100% of four hosts examined; Mean intensity: 1,5 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: 7 parasites per host infected.

Specimens deposited: Holotype: CHIOC no. 40038 a. 3 paratypes: CHIOC nos. 40038 b–d. 9 vouchers: CHIOC nos. 40039 a–b; INPA no. 805; MPEG nos. 159–161.

ZooBank registration: The Life Science Identifier (LSID) urn:lsid:zoobank.org:act:F348B068-1E19-4729-94A3-18EFBAB15872 .

Etymology: The specific epithet derives from the Greek (siphono = tube + commus = ornament) and refers to the MCO morphology, tubular with ornaments, observed in the new species.

Comparative measurements: Table 2 .

Description: (Based on seven specimens, four mounted in Gomori trichrome, three mounted in Hoyer’s). Body fusiform 427 (301–597; n=5) long, elongated, excluding the haptor, 125 (97–171; n=6) wide at the height of germarium ( Fig. 8 ). Four cephalic lobes moderately developed; four groups of head organs; cephalic glands not observed ( Fig. 8 ). Two pairs of ocelli, anterior pair smaller than posterior pair; posterior pair of ocelli more distant than the anterior pair; accessory granules present, little scattered in the cephalic area ( Fig. 8 ). Pharynx oval 34 (30–38; n=3) long, 26 (20–33; n=3) wide; short esophagus ( Fig. 8 ). Two intestinal caeca confluent and posterior to the gonads ( Fig. 8 ). Genital pore not observed. MCO 86 (67–98; n=7) long, sclerotized, tubular, elongated, having a dilatation in the medial portion with aculeiform ornaments in the distal region ( Fig. 11 ); accessory piece absent ( Fig. 11 ). Seminal vesicle sigmoid. Uterus with sclerotized distal region. Gonads overlapping, germarium fusiform 67 (60–75; n=2) long, 27 (22–32; n=2) wide; testis elongated 42 (33–59; n=4) long, 28 (20–31; n=4) wide, dorsal to germarium ( Fig. 8 ). Prostatic reservoir not observed. Peduncle long. Haptor sub-hexagonal 61 (51–93; n=5) long, 88 (64–108; n=4) wide ( Fig. 8 ). Similar 4A hooks 14 (n=1) long ( Fig. 10 ). Seven pairs of similar hooks 41 (39–43; n=2) long; blade robust and slightly curved; shank elongated with proximal dilatation comprising more than ½ of the shank length; proximal shank dilatation 21 (20–22; n=2) long; short and softly curved point; thumb developed and rounded ( Fig. 9 ). Hook filament delicate, extending until near the shank dilatation ( Fig. 9 ).

Remarks: Anacanthorus siphonocommus sp. n. differs from the remaining congeneric species mainly based on the MCO morphology, due to the presence of dilatation in the medial portion and aculeiform ornaments in the distal region of the MCO; Anacanthorus siphonocommus sp. n. also has hooks with proximal dilatation in the shank, comprising more than ½ of the shank length.

Figures

FIGURES 8–15. Anacanthorus siphonocommus sp. n. 8. Holotype whole-mount (ventral); 9. Hook; 10. Hook 4A; 11. Male copulatory organ (MCO); Anacanthorus maratininguensis sp. n. 12. MCO; 13. Hook; 14. 4A hooks; 15. Holotype whole-mount (ventral). Fig. 8 scale of 50µm; Figs. 9–10 scale of 10µm; Fig. 11 scale of 25µm; Figs. 12–14 scale of 25µm; Fig. 15 scale of 50µm.