Cichlidogyrus bixlerzavalai Jorissen, 2018

Jorissen, Michiel W. P., Pariselle, Antoine, Huyse, Tine, Vreven, Emmanuel J., Snoeks, Jos, Decru, Eva, Kusters, Thomas, Lunkayilakio, Soleil Wamuini, Bukinga, Fidel Muterezi, Artois, Tom & Vanhove, Maarten P. M., 2018, Six new dactylogyrid species (Platyhelminthes, Monogenea) from the gills of cichlids (Teleostei, Cichliformes) from the Lower Congo Basin, Parasite (Paris, France) 25 (64), pp. 1-21 : 3-4

Cichlidogyrus bixlerzavalai Jorissen ,

Pariselle & Vanhove n. sp.

urn:lsid:zoobank.org:act:3E7C4017-8E0E-4DE3-A3BD-6CD67D806601

Type host: Tylochromis praecox Stiassny, 1989 .

Infection site: Gills.

Type locality: Muila Kaku, mangroves near Lower Congo River 05° 5903300 S 12° 35003.200 E.

Material: Four whole-mounted specimens in Malmberg’s solution.

Holotype: M. T.38339.

Paratypes: M. T.38340–41, KN10053 https://laji.fi/en/ view?uri=luomus:KN.10053 .

Etymology: The species epithet is a homage to singer Cedric Bixler-Zavala of bands At the drive-in, The Mars Volta and Antemasque and is a noun (name) in the genitive case.

Authorship: Note that the authors of the new taxon are different from the authors of this paper; Article 50.1 and Recommendation 50A of International Code of Zoological Nomenclature [13].

Description ( Table 3 , Figs. 3 , 4a–4c )

Dorsal anchors with guard length 4 to 5 times the shaft length. U-shaped indentation at the base. Point short and curved (e = 11 µm). Ventral anchors 10 µm smaller than dorsal ones. Blade equally long as in dorsal anchors, but base of the ventral anchors shorter, with deeper V-shaped indentation. Hooks pair I long (>1.7 times the length of hooks pair II [35]), with rectangular-shaped shaft, slightly broader than the anterior, larval part. Hooks pair III –VII short (<2 times the length of hooks pair II [35]). Ventral transverse bar large (X = 53 µm) and broad (W = 9 µm) with lateral extension on each arm. Extension long, covers around 70% of the length of each arm, except for the proximal and distal ends. Dorsal transverse bar with short auricles (h = 12 µm), with usual morphology for species of Cichlidogyrus infecting species of Tylochromis (i.e. auricles in continuity with dorsal bar anterior face [23, 28]). Penis, thick-walled, tubular with a sinuous curve most proximally, followed by a 360° loop. At the distal end, the penis curves approximately 60°. Basal bulb granulated. Heel absent. Accessory piece not directly connected to the basal bulb. It starts at the height of the loop, where it is club-shaped and ridged. Further distally, it narrows until it is thinner than the penis.

Remarks

Species of Cichlidogyrus that infect species of Tylochromis have reduced auricles on the dorsal transverse bar. The accessory piece does not connect to the basal bulb of the penis [23, 28]. However, a thin, filamentous connection was described for C. sigmocirrus Pariselle, Bitja Nyom, Bilong Bilong, 2014 and C. chrysopiformis Pariselle, Bitja Nyom, Bilong Bilong, 2014 [36], but with uncertainty. Both species were described from Tylochromis sudanensis Daget, 1954 from the Cross River in Cameroon [36]. Furthermore, all species have a tubular curved penis, referred to as a spirally-winding penis [23]. Cichlidogyrus bixlerzavalai n. sp. resembles C. muzumanii Muterezi Bukinga, Vanhove, Van Steenberge & Pariselle, 2012 the most, as both species have large anchors with a long guard, elongated hooks pair I and a curved tubular penis with an accessory piece at the distal end of the penis that runs to almost half of the length of the penis. The major difference between these species is that in C. muzumanii , the accessory piece engulfs the penis partially, while in C. bixlerzavalai n. sp., the accessory piece lies separate from the penis. This has never been observed for species of Cichlidogyrus . It remains unclear if and where the accessory piece attaches to the penis in C. bixlerzavalai n. sp. However, it is certain that the accessory piece does not connect to the basal bulb proximally and that the accessory piece does not engulf the distal end of the penis. One specimen has a bulge-shaped extension at the distal end of the penis, but this is probably an artefact, because it is an open structure, clearly observable and absent on other specimens. Additionally, the specimen with the extension is also the only one of which the distal end of the penis is oriented towards the accessory piece. It is observed on this specimen that at the 360° loop the penis turns in the other direction. However, this directional change is likely the result of the flattening of the MCO. On one specimen, ridges at the proximal end of the accessory piece were not observed.

Figures

Figure 3. Haptoral and genital hard parts of Cichlidogyrus bixlerzavalai n. sp. from Tylochromis praecox. Accessory piece of the MCO in grey, to highlight the plate-like structure of the accessory piece. I–VII, hooks; AP, accessory piece; DA, dorsal anchors; DB, dorsal transverse bar; MCO, male copulatory organ; Pe, penis; VA, ventral anchors; VB, ventral transverse bar. Scale bar: 20 µm.

Figure 4. Compound micrographs of (a–c) Cichlidogyrus bixlerzavalai n. sp. from Tylochromis praecox: haptor of holotype (a), MCO of holotype (b) and MCO of paratype (c); of (d–f) Cichlidogyrus calycinus n. sp. from Hemichromis elongatus: haptor of holotype (d), MCO of holotype (e), vagina of holotype (f); of (g–h) Cichlidogyrus polyenso n. sp. from Hemichromis elongatus: haptor (g), MCO (h). Scale bar 20 µm, except for (g) 50 µm.