Procamallanus (Procamallanus) pseudolaeviconchus, Moravec and van As, 2015

Nofal, Ashlee P., Dos Santos, Quinton M., Jirsa, Franz & Avenant-Oldewage, Annemari`e, 2022, Camallanid nematodes from Clarias gariepinus (Burchell, 1822) in the Crocodile River, Gauteng, South Africa: Exploring diversity and divergence in an acid-mine drainage impacted environment, International Journal for Parasitology: Parasites and Wildlife 19, pp. 196-210 : 206

4.1. Procamallanus (Procamallanus) pseudolaeviconchus

The morphometry of P. (P.) pseudolaeviconchus described in this study conforms to the description by Moravec and van As (2015a), the studies by Moravec (2019) and Svitin et al. (2019), as well as those reported as P. (P.) laeviconchus from clariid hosts ( Moravec, 1975; Boomker, 1982; Barson and Avenant-Oldewage, 2006) with minor differences. Variation was noted at the caudal end of females, with either three or four digit-like processes observed on the tail tip. Barson and Avenant-Oldewage (2006) reported three digit-like processes. Similarly, Moravec and van As (2015a) reported adult females with three digit-like processes, one situated dorsally and the rest subventrally. The dorsal process appears larger and distinctly different to the subventral processes in the present material. However, Moravec (2019) described the larvae of P. (P.) pseudolaeviconchus and recorded four conical digital processes on third-stage larvae, whereas Barson and Avenant-Oldewage (2006) suggested that a specimen studied using SEM was likely a fourth-stage larva as it lacked digit-like processes. There is no mention of these structures in the females studied by Svitin et al. (2019). Therefore, the variation observed in the number of digit-like processes in the current study are most likely related to development.

Furthermore, cloacal papillae in males also varied, with Moravec (1975) and Boomker (1982) reporting eight precloacal papillae, whereas Barson and Avenant-Oldewage (2006), Moravec and van As (2015) and Moravec (2019) report nine to ten papillae. Also, Moravec and van As (2015a) and Moravec (2019) reported an additional pair of ventral sessile papillae. In comparison, the current study reports eight to nine precloacal papillae in males. It appears that this variation might be due to designation and counting of papillae, apart from the report by Moravec (1975). In that study, he listed three pairs adcloacal papillae and six pairs of postcloacal papillae, which is much more than other records for P. (P.) pseudolaeviconchus , but this variation is not mentioned in subsequent studies even by the same author (Moravec and van As, 2015; Moravec 2019).

The current study observed isolated buccal capsules for P. (P.) pseudolaeviconchus for the first time. This allowed for the confirmation of the crescent-shaped marginal elevations on the anterior margin, the distinctly smooth inner surface, and the narrow ring above the basal ring ( Moravec and van As, 2015a; Svitin et al., 2019). The right and left spiculae were also isolated and observed using SEM for the first time. The right (large) spicule is more sclerotised than the left, however both are simple and similar in shape. Moravec and van As (2015a) and Svitin et al. (2019) refer to the distal tips as being ‘sharply’ pointed, however, the right spicule tip appears to be slightly rounded in the present study, not ending in a distinct apex. Additionally, the surface topography of the vulva was described using SEM for the first time. Although there was a SEM image of a Procamallanus vulva in the study of Maˇsova´et al. (2011), the species was not identified and a first-stage larvae is being released from the vulva, obscuring the gross morphology of the vulval opening. Moravec and van As (2015a) mention the vulva having ‘elevated lips’ whereas Svitin et al. (2019) refers to a small opening situated posteriorly of a body wall projection. The current study combines these ideas as the elevated vulva forms a body wall projection with a lateral opening surrounded by lips.