A world of taxonomic pain: cryptic species, inexplicable host-specificity, and host-induced morphological variation among species of Bivesicula Yamaguti, 1934 (Trematoda: Bivesiculidae) from Indo-Pacific Holocentridae, Muraenidae and Serranidae

A comprehensive genetic and morphological analysis reveals that the genus Bivesicula, parasitic trematodes infecting Indo-Pacific fishes, is not monophyletic, with three distinct clades identified. The study distinguishes 10 species, including five new ones, highlighting significant host-specificity and geographical distribution patterns. Cryptic species, where morphological differences are minimal but genetic markers show clear distinctions, were found in both Clade 1 and Clade 2, infecting serranids with some also affecting holocentrids or muraenids. The research underscores the complexity of taxonomic classification in this genus due to low resolving power of ribosomal markers, regional mtDNA populations, and host-induced morphological variation.

Cribb, T. H., Bray, R. A., Justine, J.-L., Reimer, J., Sasal, P., Shirakashi, S., & Cutmore, S. C. (2022). A world of taxonomic pain: cryptic species, inexplicable host-specificity, and host-induced morphological variation among species of Bivesicula Yamaguti, 1934 (Trematoda: Bivesiculidae) from Indo-Pacific Holocentridae, Muraenidae and Serranidae. Parasitology, 149(6), 831–853. https://doi.org/10.1017/s0031182022000282