1
|
Kita Y, Hiruta SF, Sasaki M, Kajihara H. Systematic position of the genus Metacanthocephalus Yamaguti, 1959 (Palaeacanthocephala: Echinorhynchida) inferred from molecular evidence, with a redescription of Metacanthocephalus ovicephalus (Zhukov, 1960). Parasitol Int 2023; 94:102731. [PMID: 36623803 DOI: 10.1016/j.parint.2023.102731] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/28/2022] [Accepted: 01/05/2023] [Indexed: 01/09/2023]
Abstract
The familial affiliation of the echinorhynchid palaeacanthocephalan genus Metacanthocephalus has been uncertain, with the three families Echinorhynchidae, Leptorhynchoididae, and Rhadinorhynchidae having been suggested as its parent taxon. In this study, adult individuals of Metacanthocephalus ovicephalus from the intestine of the cresthead flounder Pseudopleuronectes schrenki (new host) and the dark flounder Pseudopleuronectes obscurus in Hokkaido, Japan, were examined. Using three gene markers (mitochondrial cytochrome c oxidase subunit I; nuclear 18S and 28S rRNA genes) determined from two specimens of M. ovicephalus, a molecular phylogenetic analysis was performed along with relevant sequences available in public databases representing 26 species in eight families of the order Echinorhynchida, along with five species from Polymorphida and two from Eoacanthocephala. The resulting phylogram showed that M. ovicephalus was nested within a clade along with nine species in eight genera (Brentisentis yangtzensis, Dentitruncus truttae, Dollfusentis bravoae, Koronacantha mexicana, K. pectinaria, Leptorhynchoides thecatus, Neotegorhynchus cyprini, Pseudoleptorhynchoides lamothei, and Tegorhynchus [= Illiosentis] sp.). In this paper, we propose i) a set of morphological characters to circumscribe members represented by this clade as a Linnaean higher taxon, ii) to place this taxon at the rank of family, iii) to refer to it as Leptorhynchoididae, and iv) to regard Illiosentidae as a junior synonym of Leptorhynchoididae. Our morphological examination revealed a single vaginal sphincter in M. ovicephalus, a character that was not mentioned in any of the previous literature. By this character, along with geographical distribution and host fish, six congeners currently recognized in Metacanthocephalus can be divided into two groups.
Collapse
Affiliation(s)
- Yuki Kita
- Department of Natural History Sciences, Graduate School of Science, Hokkaido University, N10 W8, Sapporo 060-0810, Japan.
| | - Shimpei F Hiruta
- The Mt. Fuji Institute for Nature and Biology, Showa University, 4562 Kamiyoshida, Fujiyoshida, Yamanashi 403-0005, Japan; Center for Molecular Biodiversity Research, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki 305-0005, Japan
| | - Mizuki Sasaki
- Department of Parasitology, Asahikawa Medical University, 2-1-1, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| | - Hiroshi Kajihara
- Faculty of Science, Hokkaido University, N10 W8, Sapporo 060-0810, Japan
| |
Collapse
|
2
|
Lafuente E, Lürig MD, Rövekamp M, Matthews B, Buser C, Vorburger C, Räsänen K. Building on 150 Years of Knowledge: The Freshwater Isopod Asellus aquaticus as an Integrative Eco-Evolutionary Model System. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.748212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Interactions between organisms and their environments are central to how biological diversity arises and how natural populations and ecosystems respond to environmental change. These interactions involve processes by which phenotypes are affected by or respond to external conditions (e.g., via phenotypic plasticity or natural selection) as well as processes by which organisms reciprocally interact with the environment (e.g., via eco-evolutionary feedbacks). Organism-environment interactions can be highly dynamic and operate on different hierarchical levels, from genes and phenotypes to populations, communities, and ecosystems. Therefore, the study of organism-environment interactions requires integrative approaches and model systems that are suitable for studies across different hierarchical levels. Here, we introduce the freshwater isopod Asellus aquaticus, a keystone species and an emerging invertebrate model system, as a prime candidate to address fundamental questions in ecology and evolution, and the interfaces therein. We review relevant fields of research that have used A. aquaticus and draft a set of specific scientific questions that can be answered using this species. Specifically, we propose that studies on A. aquaticus can help understanding (i) the influence of host-microbiome interactions on organismal and ecosystem function, (ii) the relevance of biotic interactions in ecosystem processes, and (iii) how ecological conditions and evolutionary forces facilitate phenotypic diversification.
Collapse
|
3
|
Amin OM, Heckmann RA, Dallarés S, Constenla M, Kuzmina T. Morphological and molecular description of a distinct population of Echinorhynchus gadi Zoega in Müller, 1776 (Paleacanthocephala: Echinorhynchidae) from the pacific halibut Hippoglossus stenolepis Schmidt in Alaska. Acta Parasitol 2021; 66:881-898. [PMID: 33686523 DOI: 10.1007/s11686-021-00361-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 02/24/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE Echinorhynchus gadi is one of the most widely distributed and commonly described acanthocephalans in marine fishes throughout the world. We provide a detailed morphometric and molecular description of a distinct Alaska population collected from the Pacific halibut Hippoglossus stenolepis Schmidt (Pleuronectidae) compared to those from other hosts and regions, illustrating new features never previously reported. METHODS We described new specimens by microscopical studies, augmented by SEM, Energy Dispersive x-ray and molecular analyses, and histopathology. RESULTS Specimens from Alaska were distinguished from those collected from the other geographical areas in proboscis size and its armature, especially number of hook rows and hooks per row, and length of hooks. The size of the receptacle, lemnisci, and reproductive structures in some other collections also varied from the Alaska material. X-ray scans of the gallium cut hooks depict prominent layering with high Sulfur content for tip cuts and increased calcium and phosphorus content in the base area of the hook. Sections of E. gadi specimens in the host tissue show prominent hook entanglement with subsequent connective tissue invasion also depicting the internal anatomy of certain worm structures not readily seen by other means. Molecular analyses clearly confirmed the identity of our E. gadi sequences. CONCLUSION Our Alaska population of the E. gadi complex appears to represent a novel population distinguishable by its distinct morphometrics, geography and host species. We further establish new information on the Energy Dispersive X-ray analysis in our Alaska material for future comparisons with the other siblings and explore genetic relationships among echinorhynchid genera and species.
Collapse
Affiliation(s)
- Omar M Amin
- Institute of Parasitic Diseases, 11445 E. Via Linda 2-419, Scottsdale, AZ, 85259, USA.
| | | | - Sara Dallarés
- Department of Animal Biology, Vegetal Biology and Ecology, Universitat Autònoma de Barcelona, Cerdanyola, Barcelona, Spain
| | - María Constenla
- Department of Animal Biology, Vegetal Biology and Ecology, Universitat Autònoma de Barcelona, Cerdanyola, Barcelona, Spain
| | | |
Collapse
|
4
|
Mauer KM, Schmidt H, Dittrich M, Fröbius AC, Hellmann SL, Zischler H, Hankeln T, Herlyn H. Genomics and transcriptomics of epizoic Seisonidea (Rotifera, syn. Syndermata) reveal strain formation and gradual gene loss with growing ties to the host. BMC Genomics 2021; 22:604. [PMID: 34372786 PMCID: PMC8351084 DOI: 10.1186/s12864-021-07857-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/28/2021] [Indexed: 11/20/2022] Open
Abstract
Background Seisonidea (also Seisonacea or Seisonidae) is a group of small animals living on marine crustaceans (Nebalia spec.) with only four species described so far. Its monophyletic origin with mostly free-living wheel animals (Monogononta, Bdelloidea) and endoparasitic thorny-headed worms (Acanthocephala) is widely accepted. However, the phylogenetic relationships inside the Rotifera-Acanthocephala clade (Rotifera sensulato or Syndermata) are subject to ongoing debate, with consequences for our understanding of how genomes and lifestyles might have evolved. To gain new insights, we analyzed first drafts of the genome and transcriptome of the key taxon Seisonidea. Results Analyses of gDNA-Seq and mRNA-Seq data uncovered two genetically distinct lineages in Seison nebaliae Grube, 1861 off the French Channel coast. Their mitochondrial haplotypes shared only 82% sequence identity despite identical gene order. In the nuclear genome, distinct linages were reflected in different gene compactness, GC content and codon usage. The haploid nuclear genome spans ca. 46 Mb, of which 96% were reconstructed. According to ~ 23,000 SuperTranscripts, gene number in S. nebaliae should be within the range published for other members of Rotifera-Acanthocephala. Consistent with this, numbers of metazoan core orthologues and ANTP-type transcriptional regulatory genes in the S. nebaliae genome assembly were between the corresponding numbers in the other assemblies analyzed. We additionally provide evidence that a basal branching of Seisonidea within Rotifera-Acanthocephala could reflect attraction to the outgroup. Accordingly, rooting via a reconstructed ancestral sequence led to monophyletic Pararotatoria (Seisonidea+Acanthocephala) within Hemirotifera (Bdelloidea+Pararotatoria). Conclusion Matching genome/transcriptome metrics with the above phylogenetic hypothesis suggests that a haploid nuclear genome of about 50 Mb represents the plesiomorphic state for Rotifera-Acanthocephala. Smaller genome size in S. nebaliae probably results from subsequent reduction. In contrast, genome size should have increased independently in monogononts as well as bdelloid and acanthocephalan stem lines. The present data additionally indicate a decrease in gene repertoire from free-living to epizoic and endoparasitic lifestyles. Potentially, this reflects corresponding steps from the root of Rotifera-Acanthocephala via the last common ancestors of Hemirotifera and Pararotatoria to the one of Acanthocephala. Lastly, rooting via a reconstructed ancestral sequence may prove useful in phylogenetic analyses of other deep splits. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07857-y.
Collapse
Affiliation(s)
- Katharina M Mauer
- Institute of Organismic and Molecular Evolution (iomE), Anthropology, Johannes Gutenberg University Mainz, Mainz, Germany.
| | - Hanno Schmidt
- Institute of Organismic and Molecular Evolution (iomE), Anthropology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Marco Dittrich
- Institute of Organismic and Molecular Evolution (iomE), Anthropology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Andreas C Fröbius
- Molecular Andrology, Biomedical Research Center Seltersberg (BFS), Justus Liebig University Gießen, Giessen, Germany
| | - Sören Lukas Hellmann
- Institute of Organismic and Molecular Evolution (iomE), Molecular Genetics and Genomic Analysis Group, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Hans Zischler
- Institute of Organismic and Molecular Evolution (iomE), Anthropology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Thomas Hankeln
- Institute of Organismic and Molecular Evolution (iomE), Molecular Genetics and Genomic Analysis Group, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Holger Herlyn
- Institute of Organismic and Molecular Evolution (iomE), Anthropology, Johannes Gutenberg University Mainz, Mainz, Germany.
| |
Collapse
|
5
|
New perspectives on Aspersentis Megarhynchus (Acanthocephala: Heteracanthocephalidae) from Notothenia Coriiceps Richardson (Nototheniidae) in the West Antarctic, with emended generic diagnosis. J Helminthol 2021; 95:e27. [PMID: 34030754 DOI: 10.1017/s0022149x2100016x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A number of variable descriptive accounts of Aspersentis megarhynchus (von Linstow, 1892) Golvan, 1960 have been reported from specimens collected from many species of fish in various locations off Antarctic islands. We have described a new population from Notothenia coriiceps Richardson (Nototheniidae) off Galindez Island, West Antarctica, and features not previously reported, resolved the taxonomic controversies and nomenclature, and emended and updated the generic diagnosis taking into account the newly observed structures. These are depicted in microscopic images and include the outer spiral wall of the proboscis receptacle, the thicker dorsal wall of the receptacle compared to the ventral wall, parts of the female reproductive system, the separate cement gland ducts, the dorsal position of the male gonopore and more detail of proboscis hooks and trunk spines. It is surprising that the newly observed features were missed from the many descriptions of A. megarhynchus created since the original description. The variability in A. megarhynchus is noted with a comparison of the morphometrics of our specimens vs. those in six other descriptions. We also analysed the metal composition of hooks and spines using energy-dispersive X-ray analysis and concluded a molecular characterization of the species based on 18S DNA gene, with related phylogenetic analyses.
Collapse
|
6
|
Parasitism with Acanthocephalus Ranae in Frogs ( Pelophylax Ridibundus Pallas 1771), from North-east Romania. Helminthologia 2021; 58:68-73. [PMID: 33664619 PMCID: PMC7912229 DOI: 10.2478/helm-2021-0008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 12/01/2020] [Indexed: 11/24/2022] Open
Abstract
The present study was carried out on 10 frogs, Pelophylax ridibundus (Pallas, 1771), captured near the river Bahlui, Iasi, between April and May, 2019, for the study of digestive helminths and their effect on the digestive tract. Macroscopic examination of the general cavity revealed distension of the small intestine. The sectioning of the intestinal wall revealed a variable number of parasites (1 – 12) with a whitish cylindrical body, anchored in the duodenal mucosa. The morphological study of the parasites confirmed the species as Acantocephalus ranae. The prevalence of the infection was 60 % and the average intensity was 4.83 ± 4.15. Lesions of the small intestine were characterized by catarrhal enteritis, hemorrhagic spots and ulcers on the mucosa, occlusion and obstruction of the intestinal lumen. Histologically, eosinophilic inflammatory infiltrate in the glandular crypts, mucosal and submucosal edema, fibrosis and conjunctival hyperplasia, total mucosal atrophy, were found. The infection with Acanthocephalus ranae in Pelophylax ridibundus caused severe pathological changes, conditioned by the intensity of the infection, aspects revealed for the first time in Romania.
Collapse
|
7
|
García-Varela M, Andrade-Gómez L. First steps to understand the systematics of Echinorhynchidae Cobbold, 1876 (Acanthocephala), inferred through nuclear gene sequences. Parasitol Int 2020; 81:102264. [PMID: 33301950 DOI: 10.1016/j.parint.2020.102264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/29/2020] [Accepted: 11/30/2020] [Indexed: 11/15/2022]
Abstract
Acanthocephalans of the order Echinorhynchida are one of the most diverse groups in their phylum, with approximately 470 species classified into 11 families that largely consist of parasites of freshwater, brackish and marine fishes and, sporadically, reptiles and amphibians distributed worldwide. Previous phylogenies inferred with molecular data have supported the paraphyly or polyphyly of some families, suggesting that most of them have been diagnosed based on unique combinations of characters, rather than shared derivative features. We expand the taxonomic sampling of several genera such as Acanthocephalus, Echinorhynchus and Pseudoacanthocephalus of Echinorhynchidae from diverse biogeographical zones in the Americas, Europe and Asia with the aim of testing the monophyly of the family by using two molecular markers. Sequences from small (SSU) and large (LSU) subunits of ribosomal DNA were obtained for six species representing the genera Acanthocephalus and Echinorhynchus from the Neotropical, Nearctic, Palearctic and Oriental regions. These sequences were aligned with other sequences available in the GenBank dataset from Echinorhynchidae. Phylogenetic trees inferred with the combined (SSU + LSU) and the individual data sets consistently placed the genera Acanthocephalus, Pseudoacanthocephalus and Echinorhynchus into three independent lineages. Two families, Paracanthocephalidae Golvan, 1960, and Pseudoacanthocephalidae Petrochenko, 1956, were resurrected to accommodate the genera Acanthocephalus and Pseudoacanthocephalus, respectively. The species of the genus Acanthocephalus from the Nearctic, Palearctic and Oriental biogeographic regions formed a clade that was well supported. However, Acanthocephalus amini from the Neotropical region was nested inside Arhythmacanthidae. Therefore, the genus Calakmulrhynchus was created to accommodate A. amini and resolve the paraphyly of Acanthocephalus. Finally, the diagnoses of the families Echinorhynchidae and Arhythmacanthidae were amended. The molecular phylogenies should be used as a taxonomic framework to find shared derived characters (synapomorphies) and build a more robust classification scheme that reflects the evolutionary history of the acanthocephalans.
Collapse
Affiliation(s)
- Martín García-Varela
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Ciudad Universitaria, Ciudad de México C.P. 04510, Mexico.
| | - Leopoldo Andrade-Gómez
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Ciudad Universitaria, Ciudad de México C.P. 04510, Mexico; Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Ciudad Universitaria, Ciudad de México, C.P. 04510, Mexico
| |
Collapse
|
8
|
Nakao M, Sasaki M. Frequent infections of mountain stream fish with the amphibian acanthocephalan, Pseudoacanthocephalus toshimai (Acanthocephala: Echinorhynchidae). Parasitol Int 2020; 81:102262. [PMID: 33276142 DOI: 10.1016/j.parint.2020.102262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 06/15/2020] [Accepted: 11/25/2020] [Indexed: 11/30/2022]
Abstract
Pseudoacanthocephalus toshimai is an intestinal acanthocephalan parasite of amphibians in Hokkaido, the northernmost island of Japan. In this study, common freshwater fish of the families Salmonidae and Cottidae in mountain streams around the Kamikawa basin of Hokkaido were examined for acanthocephalan infections with P. toshimai. A total of 160 salmonids and 14 cottids were caught in 4 streams by bait fishing during summer and autumn seasons of 2019. Adult acanthocephalans were found only from the salmonids, namely, Salvelinus leucomaenis leucomaenis, Salvelinus malma krascheninnikovi, Oncorhynchus masou, and Oncorhynchus mykiss. The maximum prevalence reached 58.1% in S. leucomaenis, but the mean worm burden was at low levels (e.g., 3.1 in S. leucomaenis and 2.2 in S. malma). All of the acanthocephalans were identified to P. toshimai by morphological observation and DNA barcoding. Although the male acanthocephalans became sexually mature, the females never reached the gravid adult stage, suggesting that salmonids are unsuitable or aberrant hosts for P. toshimai. The infected fish were found exclusively from a small stream with bush, in which a large habitat of amphibians is included. Ligidium japonicum, a terrestrial isopod, collected from the habitat was highly infected with cystacanth larvae of P. toshimai. The observation of fish stomach contents directly demonstrated that small salmonids eat L. japonicum. The terrestrial isopods, which are washed away by rain into a stream, seem to be a source of salmonid infections with P. toshimai. The habitat of intermediate hosts should be emphasized in the taxonomy of the closely related genera Acanthocephalus and Pseudoacanthocephalus.
Collapse
Affiliation(s)
- Minoru Nakao
- Department of Parasitology, Asahikawa Medical University, Midorigaoka-Higashi 2-1, Asahikawa, Hokkaido 078-8510, Japan.
| | - Mizuki Sasaki
- Department of Parasitology, Asahikawa Medical University, Midorigaoka-Higashi 2-1, Asahikawa, Hokkaido 078-8510, Japan
| |
Collapse
|
9
|
Unravelling the hidden biodiversity - the establishment of DNA barcodes of fish-parasitizing Acanthocephala Koehlreuther, 1771 in view of taxonomic misidentifications, intraspecific variability and possible cryptic species. Parasitology 2020; 147:1499-1508. [PMID: 32741413 PMCID: PMC7677897 DOI: 10.1017/s0031182020001316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Acanthocephalans are obligate parasites of vertebrates, mostly of fish. There is limited knowledge about the diversity of fish-parasitizing Acanthocephala in Austria. Seven determined species and an undetermined species are recorded for Austrian waters. Morphological identification of acanthocephalans remains challenging due to their sparse morphological characters and their high intraspecific variations. DNA barcoding is an effective tool for taxonomic assignment at the species level. In this study, we provide new DNA barcoding data for three genera of Acanthocephala (Pomphorhynchus Monticelli, 1905, Echinorhynchus Zoega in Müller, 1776 and Acanthocephalus Koelreuter, 1771) obtained from different fish species in Austria and provide an important contribution to acanthocephalan taxonomy and distribution in Austrian fish. Nevertheless, the taxonomic assignment of one species must remain open. We found indications for cryptic species within Echinorhynchus cinctulus Porta, 1905. Our study underlines the difficulties in processing reliable DNA barcodes and highlights the importance of the establishment of such DNA barcodes to overcome these. To achieve this goal, it is necessary to collect and compare material across Europe allowing a comprehensive revision of the phylum in Europe.
Collapse
|