Camallanid nematodes from (Burchell, 1822) in the Crocodile River, Gauteng, South Africa: Exploring diversity and divergence in an acid-mine drainage impacted environment.

collected from Lake Heritage, Crocodile River, were found to harbour camallanid nematodes. Previously, Boomker (1982) surveyed the Hartbeespoort Dam, downstream of the current study site, and identified a high prevalence of and Since then, was described from suggesting reconsideration of the identifications of species in historical studies from clariids The aim of the current study was to definitively identify the nematodes collected from in Lake Heritage using morphological and molecular analyses Morphological study consisted of light and scanning electron microscopy which confirmed the identity and This included descriptions of the detailed morphology of isolated buccal capsules for both species using soft tissue digestion, notably for the first time for . The morphology of isolated spiculae of both species was described for the first time using SEM. Molecular analyses included genetic characterisation of the small ribosomal subunit (18S) rDNA and cytochrome oxidase 1 (CO1) mtDNA. Genetic data supported the morphological identification of both species, however, divergence was detected in CO1 mtDNA data for indicating two distinct lineages Due to this variation, the morphometry of specimens were revisited including statistical re-evaluation. No robust morphological traits were identified to support CO1 mtDNA lineages and all specimens were considered conspecific. In terms of camallanid biodiversity in the Crocodile River system, it is similar to that in Boomker (1982), despite the altered water quality from past acid mine pollution in the river.