@article {672, title = {Review of the southern African slender stonebashers, genus Heteromormyrus Steindachner 1866 (Teleostei: Mormyridae), with description of six new species}, journal = {Journal of Fish Biology}, volume = {108}, year = {2025}, month = {Sep-17-2025}, abstract = {

Recent molecular studies have advanced our knowledge of the taxonomic diversity and generic placement of the slender stonebashers, previously placed in the genus Hippopotamyrus, in southern Africa. These fishes were recently transferred to the genus Heteromormyrus whose range encompasses the Kwanza, Kunene, Okavango, Zambezi, Pungwe and Buzi River systems in southern Africa, as well as the southern tributaries of the Congo River system. The present study builds on previous research that identified at least eight candidate species within the Heteromormyrus ansorgii species complex by providing formal descriptions for six new species and redescriptions of Heteromormyrus pauciradiatus and H. ansorgii s.s. The Kwanza River system is peculiar because it currently has five known species in this genus, some of which are co-distributed, whereas the other river systems have only one or two species in this genus. Two of the new species, Heteromormyrus dolichorhynchus sp. nov. and Heteromormyrus angusticaudata sp. nov., are endemic to the Kwanza River system. Heteromormyrus xanekweorum sp. nov. is confined to the Okavango River system, Heteromormyrus chilembwei sp. nov. occurs in the Ruo River (lower Zambezi River system), Heteromormyrus tangwenai sp. nov. is endemic to the Pungwe River system and Heteromormyrus ndauorum sp. nov. is endemic to the Buzi River system. Species in this genus exhibit high morphological similarity, but they can be separated by a combination of characters, including scale counts, dorsal- and anal-fin ray counts, vertebral counts, caudal peduncle depth, position of nostrils, head shape and variation in colour pattern. Taxonomic diversity within this genus is likely to be higher than currently known, and future studies, particularly in the Kwanza and upper Zambezi rivers, are anticipated to uncover additional new species.

}, keywords = {Diversity, freshwater, mormyrids, southern Africa, Taxonomy}, issn = {0022-1112, 1095-8649}, doi = {10.1111/jfb.70191}, url = {https://doi.org/10.1111/jfb.70191}, author = {Mutizwa, Tadiwa I. and Kadye, Wilbert T. and Bragan{\c c}a, Pedro H. N. and Chakona, Albert} } @article {607, title = {Phylogenomics of bonytongue fishes (Osteoglossomorpha) shed light on the craniofacial evolution and biogeography of the weakly electric clade Mormyridae}, journal = {Systematic Biology}, volume = {71}, year = {2022}, month = {Jan-18-2022}, pages = {1032{\textendash}1044}, chapter = {1032}, abstract = {

Abstract Bonytongues (Osteoglossomorpha) constitute an ancient clade of teleost fishes distributed in freshwater habitats throughout the world. The group includes well-known species such as arowanas, featherbacks, pirarucus, and the weakly electric fishes in the family Mormyridae. Their disjunct distribution, extreme morphologies, and electrolocating capabilities (Gymnarchidae and Mormyridae) have attracted much scientific interest, but a comprehensive phylogenetic framework for comparative analysis is missing, especially for the species-rich family Mormyridae. Of particular interest are disparate craniofacial morphologies among mormyrids which might constitute an exceptional model system to study convergent evolution. We present a phylogenomic analysis based on 546 exons of 179 species (out of 260), 28 out of 29 genera, and all six families of extant bonytongues. Based on a recent reassessment of the fossil record of osteoglossomorphs, we inferred dates of divergence among trans-continental clades and the major groups. The estimated ages of divergence among extant taxa (e.g., Osteoglossomorpha, Osteoglossiformes, Mormyroidea) are older than previous reports, but most of the divergence dates obtained for clades on separate continents are too young to be explained by simple vicariance hypotheses. Biogeographic analysis of mormyrids indicates that their high species diversity in the Congo Basin is a consequence of range reductions of previously widespread ancestors and that the highest diversity of craniofacial morphologies among mormyrids originated in this basin. Special emphasis on a taxon-rich representation for mormyrids revealed pervasive misalignment between our phylogenomic results and mormyrid taxonomy due to repeated instances of convergence for extreme craniofacial morphologies. Estimation of ancestral phenotypes revealed contingent evolution of snout elongation and unique projections from the lower jaw to form the distinctive Schnauzenorgan. Synthesis of comparative analyses suggests that the remarkable craniofacial morphologies of mormyrids evolved convergently due to niche partitioning, likely enabled by interactions between their exclusive morphological and electrosensory adaptations.

}, keywords = {Africa, Ancestral State Estimation, Diversity, Exon Capture, Freshwater fishes, Phylogenomics}, issn = {1063-5157, 1076-836X}, doi = {10.1093/sysbio/syac001}, url = {http://dx.doi.org/10.1093/sysbio/syac001}, author = {Rose Peterson and John P Sullivan and Carl D Hopkins and Santaquiteria, Aintzane and Casey B. Dillman and Stacy Pirro and Betancur-R, Ricardo and Arcila, Dahiana and Hughes, Lily C and Ort{\'\i}, Guillermo} }