Anacanthorus scyphophallus, 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 : 304-305

Anacanthorus scyphophallus sp. n.

( Figs. 1–3 )

Type-host: Erythrinus erythrinus (Bloch & Schneider) , 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).

Prevalence: 50% of two hosts examined.

Mean intensity: 5 parasites per host infected.

Specimens deposited: Holotype: CHIOC no. 40037 a. 3 paratypes: CHIOC nos. 40037 b–d.

ZooBank registration: The Life Science Identifier (LSID) urn:lsid:zoobank.org:act:F168AB80-F090-46FA-BE3A-E1D45A7F5AA0 .

Etymology: The specific epithet derives from the Greek (scypho = cup + phallus = penis) and refers to the MCO morphology, small and cup-shaped.

Description: (Based on four specimens, two mounted in Gomori trichrome, two mounted in Hoyer’s). Elongated and fusiform body 378 (235–566; n=4) long, excluding the haptor, 88 (65–117; n=4) wide at the height of germarium ( Fig. 1 ). Four cephalic lobes poorly developed; four groups of head organs; cephalic glands not observed. Two pairs of ocelli, anterior pair smaller than the posterior pair; accessory granules present or absent, oval-shaped, scattered in the cephalic area ( Fig. 1 ). Pharynx subspherical 30 (24–36; n=4) long, 27 (21–37; n=4) wide; short esophagus ( Fig. 1 ). Two intestinal caeca, confluent, posterior to the gonads ( Fig.1 ). Male copulatory organ (MCO) 27 (21–32; n=4) long, 11 (9–15; n=4) wide, sclerotized, tubular, short, cup-shaped with two small flaps in the distal portion ( Fig. 2 ); accessory piece absent ( Fig. 2 ). Seminal vesicle sigmoid. Gonads overlapping; germarium fusiform 57 (40–78; n=4) long, 21 (14–28; n=4) wide; testis oval 27 (n=1) long, 16 (n=1) wide, dorsal to germarium ( Fig. 1 ). Prostatic reservoir, uterus, genital pore, and egg not observed. Peduncle elongated ( Fig. 1 ). Haptor subtriangular 54 (31–73; n=4) long, 45 (30–56; n=4) wide ( Fig. 1 ). 4A hooks not observed. Seven pairs of similar hooks 35 (34–37; n=3) long, blade moderately elongated, point short and slightly curved, thumb rounded and poorly developed and shank 17 (16–18; n=3) long, with proximal dilatation comprising ½ of the shank length ( Fig. 3 ). Hook filament delicate, extending until near the shank dilatation ( Fig. 3 ).

Remarks: Anacanthorus scyphophallus sp. n. is similar to Anacanthorus brevicirrus Monteiro, Kritsky & Brasil-Sato, 2010 based on the MCO morphology. Anacanthorus scyphophallus sp. n. has a hook with rounded thumb and shank with proximal dilatation comprising ½ of the shank length, whereas A. brevicirrus has reduced thumb and shank with a small dilatation in the proximal region in the form of a bulb, containing a translucent spot. Moreover, the new species is characterized by overlapping gonads (tandem in A. brevicirrus ).

Figures

FIGURES 1–7. Anacanthorus scyphophallus sp. n. 1. Holotype whole-mount (ventral); 2. Male copulatory organ (MCO); 3. Hook. Anacanthorus ataidei sp. n. 4. MCO; 5. Hook; 6. 4A hooks; 7. Holotype whole-mount (ventral). Fig. 1 scale of 50µm; Figs. 2–3 scale of 25µm; Fig. 4 scale of 25µm; Figs. 5–6 scale of 10µm; Fig. 7 scale of 50µm.