A new species of Ceratomyxa (Ceratomyxidae, Myxosporea) was found infecting the gall bladder of the Argentine croaker Umbrina canosai Berg 1895 (Sciaenidae, Perciformes) from the Argentine sea. Using an integrative taxonomic approach that combines morphological, bioecological, and molecular analyses, we provide evidence that clearly differentiates this species from known taxa and formally describe Ceratomyxa fialai as a new species. This study is the first to apply landmark-based geometric morphometrics (GM) in myxozoan research, providing a detailed analysis of conspecific morphometric variation of ceratomyxid myxospores, examining their natural variation within and among different ceratomyxids infecting the gall bladder of U. canosai. Using GM analyses, we successfully capture and quantify phenotypic variation at the organismal level. Our results suggest that myxospore shape variation may be driven by both developmental noise and phenotypic plasticity. The work highlights the utility of GM in advancing the understanding of myxozoan morphology and its evolutionary implications and emphasizes the need for further research on myxospore shape evolution and its ecological and adaptive significance in natural populations.

• Klíčová slova
• Argentina, Ceratomyxa fialai n. sp., Myxozoa, myxospore shape variation,
• Publikační typ
• časopisecké články MeSH

INTRODUCTION: Intertidal rock pools where fish and invertebrates are in constant close contact due to limited space and water level fluctuations represent ideal conditions to promote life cycles in parasites using these two alternate hosts and to study speciation processes that could contribute to understanding the roles of parasitic species in such ecosystems. MATERIAL AND METHODS: Gall bladder and liver samples from five clinid fish species (Blenniiformes: Clinidae) were morphologically and molecularly examined to determine the diversity, prevalence, distribution and host specificity of Ceratomyxa parasites (Cnidaria: Myxozoa) in intertidal habitats along the coast of South Africa. Phylogenetic relationships of clinid ceratomyxids based on the SSU rDNA, LSU rDNA and ITS regions were assessed additionally to the investigation of population genetic structure of Ceratomyxa cottoidii and subsequent comparison with the data known from type fish host Clinus cottoides. RESULTS AND DISCUSSION: Seven Ceratomyxa species including previously described Ceratomyxa dehoopi and C. cottoidii were recognized in clinids. They represent a diverse group of rapidly evolving, closely related species with a remarkably high prevalence in their hosts, little host specificity and frequent concurrent infections, most probably as a result of parasite radiation after multiple speciation events triggered by limited host dispersal within restricted spaces. C. cottoidii represents the most common clinid parasite with a population structure characterized by young expanding populations in the south west and south east coast and by older populations in equilibrium on the west coast of its distribution. Parasite and fish host population structures show overlapping patterns and are very likely affected by similar oceanographic barriers possibly due to reduced host dispersal enhancing parasite community differentiation. While fish host specificity had little impact on parasite population structure, the habitat preference of the alternate invertebrate host as well as tidal water exchange may be additional crucial variables affecting the dispersal and associated population structure of C. cottoidii.

• MeSH
• fylogeneze MeSH
• interakce hostitele a parazita genetika   fyziologie   MeSH
• Myxozoa klasifikace   genetika   MeSH
• nemoci ryb parazitologie   MeSH
• parazitární nemoci u zvířat parazitologie   MeSH
• paraziti klasifikace   genetika   MeSH
• populační genetika metody   MeSH
• ribozomální DNA genetika   MeSH
• ryby parazitologie   MeSH
• stadia vývoje genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Jihoafrická republika MeSH
• Názvy látek
• ribozomální DNA MeSH