Pomphorhynchus bosniacus, Kiskaroly and Cankovic, 1967

Reier, Susanne, Sattmann, Helmut, Schwaha, Thomas, Harl, Josef, Konecny, Robert & Haring, Elisabeth, 2019, An integrative taxonomic approach to reveal the status of the genus Pomphorhynchus Monticelli, 1905 (Acanthocephala: Pomphorhynchidae) in Austria, International Journal for Parasitology: Parasites and Wildlife 8, pp. 145-155 : 150

3.1.3. Pomphorhynchus bosniacus

Adult and subadult specimens of a morphologically different species were found in fish obtained from the Danube ( Table 1). This species was found in high numbers (n = 186) in Barbus barbus and in one individual a mass occurrence (“polyhelminthiasis”) was observed. Moreover, subadult specimens belonging to this species were obtained from other fish species ( Table 1). Twenty-six specimens were examined and measured. The proboscis had a cylindrical shape ( Fig. 2 B ). The five anterior hooks were stouter than the posterior ones and their number was constant in each individual, while the number of the posterior hooks varied from three to four hooks per row ( Fig. 2 E ). The basal hooks on the proboscis were attached in the center of the root. The hook roots were also visible under the light microscope in fixed material, while, e.g., the hook root extensions of P. tereticollis were not visible after fixation. Hooks number four and five had a clearly stouter appearance than the anterior three hooks ( Fig. 2 B ). The last circle of hooks was located on the anterior part of the bulb ( Fig. 2 B ). The number of longitudinal rows of hooks differed from 14 to 16 longitudinal rows (in three sectioned specimens). The females were slightly larger than the males. Table 2 provides measurements of trunk size, neck length, bulb diameter, proboscis length and hook length from 17 female specimens (five adults, twelve subadults) and nine males (five adults, four subadults). Furthermore, in several specimens additional measurements of lemnisci, testes and cement glands were taken ( Table 2). Eggs were elliptic in shape and were 83.4–89.1 (86.5) μm × 15.5–18.9 (16.5) μm. Furthermore, three different neck bulb shapes were determined as described by Kiskároly and Čanković (1967). Although the specimens of this study were slightly smaller in size than P. bosniacus described by Kiskároly and Čanković (1967), the size and arrangement of the hooks, the length of the proboscis and the bulb variations ( Kiskároly and Čanković, 1967; Moravec, 2004) suggest that the Austrian specimens of the Danube belong to the same species.

Figures

Fig. 2. Proboscis and longitudinal row of hook roots of the three determined Pomphorhynchus species. All images are volume rendering of the 3-D stacks. In volume rendering each grayscale value is assigned a color according to an arbitrary colormap. The depiction depends on which values and how transparent they are displayed. In the present images a glow color map is used, which assigns graded colors from black (background) to shades of red-orange-yellow. A. Volume rendering of a confocal laser scan image stack of the proboscis of P. tereticollis. B. Volume rendering of the sectioned proboscis of P. bosniacus including reconstructed hooks as surface rendering. C. Volume rendering of the sectioned proboscis of P. laevis including reconstructed hooks as surface rendering. D-F. Internal view of the sectioned proboscids including a single longitudinal row of hooks. D. P. tereticollis. E. P. bosniacus. F. P. laevis. Legend: Red arrow = last circle of hooks; green arrow = extensions on basal hook roots of P. tereticollis; blue arrow = basal hooks attached in the middle of hook roots of P. bosniacus; yellow arrow: lack of extensions on basal hook roots of P. laevis. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)