Chromosomal-Level Reference Genome for the Chinese Endemic Pygmy Grasshopper, Zhengitettix transpicula, Sheds Light on Tetrigidae Evolution and Advancing Conservation Efforts

The pygmy grasshopper, Zhengitettix transpicula, is a Chinese endemic species with an exceedingly limited distribution and fragile population structure, rendering it vulnerable to extinction. We present a high-continuity, chromosome-scale reference genome assembly to elucidate this species' distinctive biology and inform conservation. Employing an integrated sequencing approach, we achieved a 970.40 Mb assembly with 96.32% coverage across seven pseudo-chromosomes and impressive continuity (N50 > 220 Mb). Genome annotation achieves identification with 99.2% BUSCO completeness, supporting quality. Comparative analyses with 14 genomes from Orthoptera-facilitated phylogenomics and revealed 549 significantly expanded gene families in Z. transpicula associated with metabolism, stress response, and development. However, genomic analysis exposed remarkably low heterozygosity (0.02%), implying a severe genetic bottleneck from small, fragmented populations, characteristic of species vulnerable to extinction from environmental disruptions. Elucidating the genetic basis of population dynamics and specialization provides an imperative guideline for habitat conservation and restoration of this rare organism. Moreover, divergent evolution analysis of the CYP305m2 gene regulating locust aggregation highlighted potential structural and hence functional variations between Acrididae and Tetrigidae. Our chromosomal genomic characterization of Z. transpicula advances Orthopteran resources, establishing a framework for evolutionary developmental explorations and applied conservation genomics, reversing the trajectory of this unique grasshopper lineage towards oblivion.

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

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.

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

The classification of "parasites" in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.

Human acanthocephaliasis: A thorn in the side of parasite diagnostics

Acanthacephala is a phylum of parasitic pseudocoelamates that infect a wide range of vertebrate and invertebrate hosts and can cause zoonotic infections in humans. The zoologic literature is quite rich and diverse, however the human-centric literature is sparse and sporadically reported over the past 70 years. Causal agents of acanthacephaliasis in humans are reviewed as well as their biology and life cycle. This review provides the first consolidated and summarized report of human cases of acanthacephaliasis based on English language publications, including epidemiology, clinical presentation, treatment, and diagnosis and identification.

Ecological Scenarios and Parasite Diversity in Anurans of West Africa: A Review

This paper is a survey of the parasite diversity, prevalence and infection intensity in anurans in diverse ecological settings in West Africa. The settings included natural habitats (rainforests, freshwater creeks, Guinea and Sudan savannas), monoculture plantations (cocoa, cotton and oil palm), urbanized and urbanizing rainforest biotopes and polluted environments due to oil industry activities. The natural habitats had higher amphibian species diversity, moderate parasite prevalence and low infection intensity, showing a balance in the host/parasite relationship. These habitats yielded most of the monogeneans, among which were new species. The freshwater creek biotope had low amphibian diversity, but hosts from this environment harbored several parasite taxa, a situation attributed to a prolonged wet season, high environmental humidity and persistent breeding pools for insect vectors in this area. The monoculture plantations were characterized by high parasite prevalence but lower infection intensity. For example, in the Pendjari Biosphere Reserve in Bénin Republic, the Agricultural Zone (AZ) had higher parasite prevalence values, while the National Park (NP) and Buffer Zone (BZ) had higher infection intensities. Higher prevalence was attributed to the single or combined effects of vector population explosion, immune-suppression by agrochemicals, nutrient enrichment and eutrophication from fertilizer use. The lower infection intensity was attributed to the inhibitory effect of the pesticide-contaminated environment on the free-living larval stages of parasites. The adverse effect of pesticide contamination was also evident in the lower infection intensity recorded in the anurans from the cocoa plantations at Ugboke in comparison to those from the pesticide-free village settlement. Urbanization reduced host diversity and numbers and increased the vector population, resulting in unusually high parasite prevalence and infection intensities at Diobu and Port Harcourt and high prevalence recorded for Ophidascaris larvae in the anurans of Evbuabogun. Oil pollution in the mangrove community reduced both host and parasite diversity; infection intensity was also low due to the adverse conditions confronting free-living stages of parasites in their development milieu. The high prevalence values obtained for monogeneans (Polystoma spp.) in Ptychadena spp. from Ogoniland was presumed to have resulted from host tadpole sequestration and exposure to high oncomiracidia burden in the few hospitable ponds. Also reviewed is the phenomenon of amphibian paratenism, a strategy on which many helminth parasites rely on for their trophic transmission to their definitive hosts.

First steps to understand the systematics of Echinorhynchidae Cobbold, 1876 (Acanthocephala), inferred through nuclear gene sequences

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.

Frequent infections of mountain stream fish with the amphibian acanthocephalan, Pseudoacanthocephalus toshimai (Acanthocephala: Echinorhynchidae)

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.

A new species of Pseudoacanthocephalus (Acanthocephala: Echinorhynchidae) from the guttural toad, Sclerophrys gutturalis (Bufonidae), introduced into Mauritius, with comments on the implications of the introductions of toads and their parasites into the UK

Pseudoacanthocephalus goodmani n. sp. is described from faecal pellets collected from Sclerophrys gutturalis (Power, 1927), the guttural toad. The species is characterized by a suite of characters, including a proboscis armature of 14-18 longitudinal rows of 4-6 hooks with simple roots, lemnisci longer than the proboscis receptacle, equatorial testes, a cluster of elongated cement glands and eggs without polar prolongations of the middle membrane 72.6-85.8 long. The toad had been accidentally translocated from Mauritius to the UK in a tourist's luggage and survived a washing machine cycle. The guttural toad was introduced into Mauritius from South Africa in 1922 and the cane toad, Rhinella marina (Linneaus, 1758), from South America, between 1936 and 1938. It seems most likely, therefore, that P. goodmani was introduced, with the guttural toad, from South Africa. The cane toad is host to the similar species, Pseudoacanthocephalus lutzi, from the Americas, but P. lutzi has not been recorded from places where the cane toad has been introduced elsewhere. Clearly, the guttural toad is a hardy and adaptable species, although it seems unlikely that it could become established in Northern Europe. Nevertheless, any accidental translocation of hosts poses the potential risk of introducing unwanted pathogens into the environment and should be guarded against.

Endoparasites in Limnonectes magnus (Anura, Dicroglossidae) from Samar Island, Philippines with description of a new species of Aplectana (Nematoda, Cosmocercidae)

Aplectana samarensis sp. nov. (Ascaridida, Cosmocercidae) from the intestines of Limnonectes magnus (Anura, Dicroglossidae) is described and illustrated. Aplectana samarensis sp. nov. represents the 53rd species assigned to the genus and the 6th species reported from the Oriental region. It is easily separated from the 5 species previously reported from the region by the presence of a gubernaculum and the distribution pattern of male caudal papillae: A. macintoshii has an irregular pattern, no precloacal papillae in rows; both A. akhrami and A. dubrajpuri lack a gubernaculum; A. duttaphryni has 3 pairs of precloacal papillae forming 2 rows; A. ranae has 7 pairs of precloacal papillae forming 2 rows; A. samarensis sp. nov. has 4 pairs of precloacal papillae in 2 rows. In addition to the new species, individuals of Falcaustra dubia and Pseudoacanthocephalus bufonis as well as cestode plerocercoids were also found.

Acanthocephalans from fishes and amphibians in Vietnam, with descriptions of five new species

Eight species of acanthocephalans are reported, and five are new. Specimens of Neoechinorhynchus (Hebesoma) manubrianus Amin, Ha & Ha, 2011 were similar to the original description. Neoechinorhynchus (Hebesoma) spiramuscularis n. sp. (Neoechinorhynchidae), from Xenocypris davidi, has a unique proboscis receptacle wrapped in a spiral muscular layer, and an undulating flask-shaped lemnisci, as well as double para-receptacle structures. Heterosentis mongcai n. sp. (Arhythmacanthidae), from Acreichthys sp., has a small fusiform trunk with an unarmed cone and anterior trunk spines, and a proboscis with two circles of rooted apical hooks and 3-4 circles of rooted posterior spines as well as a para-receptacle-like structure at the posterior end. The poorly known Filisoma indicum Van Cleave, 1928 is fully described and illustrated for the first time. Acanthocephalus parallelcementglandatus n. sp. (Echinorhynchidae), from Clarias batrachus, is distinguished from other species of Acanthocephalus by its small fusiform trunk and parallel tubular cement glands. Pseudoacanthocephalus coniformis n. sp. (Echinorhynchidae), from Hylarana sp., is distinguished from other species by having an anterior trunk collar and staggered prominent filiform cement glands, among other features. Cathayacanthus spinitruncatus n. sp. (Rhadinorhynchidae), from Leiognathus equulus, is distinguished from the only two known species of the genus by having a very long and slender proboscis with more than 50 hooks per row and a totally spined trunk. The generic diagnosis of Cathayacanthus Golvan, 1969 is emended. Rhadinorhynchus johnstoni Golvan, 1969 (Rhadinorhynchidae) perfectly fits the only complete description of that species from the Fiji Islands.