Phylogenetics and Ecology of Acanthocephalan Parasites

Acanthocephalans, commonly known as thorny-headed worms, represent a diverse lineage of endoparasites infecting a broad range of vertebrate hosts, including fish, amphibians, reptiles and mammals. Molecular phylogenetic analyses have redefined their internal classification into major clades (Archiacanthocephala, Eoacanthocephala, Palaeacanthocephala and Polyacanthocephala), challenging traditional morphology-based orders. Integrative approaches combining nuclear ribosomal genes (18S, 28S), mitochondrial markers (cox1, cox2, 12S) and complete mitogenomes have improved resolution of evolutionary relationships and illuminated cases of paraphyly within key taxa. Ecologically, acanthocephalans exhibit complex life cycles involving arthropod intermediate hosts and vertebrate definitive hosts, with transmission strategies that influence food-web dynamics. Their capacity for host-induced phenotypic alteration, and high accumulation of environmental contaminants, renders them valuable models for studying parasite–host co-evolution, behavioural manipulation and aquatic ecotoxicology. Continuous discovery of cryptic lineages and novel species underlines their global biodiversity and highlights the need for broad taxonomic and ecological surveys.

Research from Nature Portfolio

Recent studies have revealed cryptic diversity in gastrointestinal acanthocephalans infecting New World primates. High-resolution analyses of mitochondrial cox1 sequences, combined with haplotype network reconstructions and Bayesian phylogenetic inference, uncovered deep genetic divergence between populations from different Central American regions. These findings demonstrate lineage-specific adaptations and previously unrecognised species-level diversity within a nominal taxon, emphasising the utility of multilocus molecular approaches to resolve fine-scale phylogenetic relationships. This work also underscores the importance of regional surveys in revealing hidden biodiversity and informing conservation management of both hosts and parasites.

Phylogenetics and Ecology of Acanthocephalan Parasites publication trend

The graph below shows the total number of articles in phylogenetics and ecology of acanthocephalan parasites across all publications each year (not limited to Nature Index journals).

Technical terms

Cryptic diversity: The presence of genetically distinct lineages within morphologically similar organisms, revealed only through molecular markers.

Bayesian Inference: A statistical framework for reconstructing phylogenetic trees by estimating the probability of evolutionary models given the data.

Haplotype network: A visual representation of relationships among DNA sequence variants, indicating mutational steps between haplotypes.

Mitogenome: The complete mitochondrial genome, widely used in phylogenetic and population genetic studies due to its conserved structure and maternal inheritance.

Ecological fitting: The colonisation of new hosts or environments by organisms using pre-existing traits without novel adaptations.

Integrative taxonomy: A multidisciplinary approach combining morphological, molecular, ecological and other data to robustly delimit species.

References

1. Cryptic diversity in a gastrointestinal acanthocephalan of New World primates from Costa Rica. Scientific Reports (2023).
2. Integrative taxonomy of the genus Pseudoacanthocephalus (Acanthocephala: Echinorhynchida) in China, with the description of two new species and the characterization of the mitochondrial genomes of Pseudoacanthocephalus sichuanensis sp. n. and Pseudoacanthocephalus nguyenthileae. Parasites & Vectors (2024).
3. Hooking the scientific community on thorny-headed worms: interesting and exciting facts, knowledge gaps and perspectives for research directions on Acanthocephala. Parasite (2023).