Phylomitogenomic Analyses Provided Further Evidence for the Resurrection of the Family Pseudoacanthocephalidae (Acanthocephala: Echinorhynchida)

Abstract

The phylum Acanthocephala is an important monophyletic group of parasites, with adults parasitic in the digestive tracts of all major vertebrate groups. Acanthocephalans are of veterinary, medical, and economic importance due to their ability to cause disease in domestic animals, wildlife, and humans. However, the current genetic data for acanthocephalans are sparse, both in terms of the proportion of taxa surveyed and the number of genes sequenced. Consequently, the basic molecular phylogenetic framework for the phylum is still incomplete. In the present study, we reported the first complete mitochondrial genome from a representative of the family Pseudoacanthocephalidae Petrochenko, 1956. The mitogenome of Pseudoacanthocephalus bufonis (Shipley, 1903) is 14,056 bp in length, contains 36 genes (12 protein-coding genes (PCGs) (lacking atp8), 22 tRNA genes, and 2 rRNA genes (rrnL and rrnS)) and two non-coding regions (NCR1 and NCR2), and displayed the highest GC-skew in the order Echinorhynchida. Phylogenetic results of maximum likelihood (ML) and Bayesian inference (BI) using the amino acid sequences of 12 protein-coding genes in different models provided further evidence for the resurrection of the family Pseudoacanthocephalidae and also supported that the order Echinorhynchida is paraphyletic. A monophyletic clade comprising P. bufonis and Cavisoma magnum suggests a close affinity between Pseudoacanthocephalidae and Cavisomatidae. Our phylogenetic analyses also showed that Polymorphidae has a closer relationship with Centrorhynchidae than Plagiorhynchidae in the monophyletic order Polymorphida.

Mitogenomic Phylogeny of Tonnoidea Suter, 1913 (1825) (Gastropoda: Caenogastropoda)

“…In the nine mitogenomes, AT skew values ranged from −0.111 to −0.093 and GC skews values ranged from 0.015 to 0.075, indicating that the frequencies of A and C on the major chain are lower than T and G, respectively. Similar results have also been found in other invertebrate groups [44,45].…”

Diversity of Acanthocephala parasites in Neotropical amphibians

“…Therefore, we emphasize the importance of comprehensive parasite inventories. Moreover, the inclusion of molecular tools for identifying acanthocephalan species, already highlighted in other studies (Selbach et al 2019; Zhao et al 2023), can help fill one of the main gaps highlighted in this study, which is the lack of species level identification. At the same time, the inclusion of ecological information about hosts, such as diet and habitat, can contribute to a better understanding of the life strategies of acanthocephalans.…”

“…Thus, non-specific reports were very common. This aspect, coupled with the scarcity of specialists in the field (Perrot-Minnot et al 2023) and the inherent complexity of parasite identification (Selbach et al 2019; Zhao et al 2023), contributes to a taxonomic gap for acanthocephalans.…”

Chromosome analysis and the occurrence of B chromosomes in fish parasite Acanthocephalus anguillae (Palaeacanthocephala: Echinorhynchida)

“…The phylum includes about 1,270 extant species with diverse life cycles involving arthropods as intermediate hosts and vertebrates as definitive hosts [ 54 ]. They are classified into four classes based on morphological characteristics [ 1 , 34 ], but the validity of the fourth class, Polyacanthocephala, is being questioned based on recent molecular data [ 82 ]. Currently, despite the growing number of molecular phylogenies and the inclusion of new molecular markers in combination with morphological data, phylogenetic relationships at the family and genus levels remain unresolved and many questions remain unanswered [ 22 , 23 , 28 ].…”