Systematics of Pseudocavisoma (Acanthocephala: Echinorhynchida): assessment of familial affiliation, establishment of a new species, and complementary redescription of the type species based on syntypes.

The familial affiliation of the so-far-monotypic palaeacanthocephalan genus Pseudocavisoma Golvan & Houin, 1964 has solely been based on morphological characteristics, lacking nucleotide sequence data. In this paper, we assess the phylogenetic position of the genus with a dataset consisting of partial sequences of the mitochondrial cytochrome c oxidase subunit I, and the nuclear 18S and 28S rRNA genes for 37 species of palaeacanthocephalans available in public databases along with the ones determined from the new species Pseudocavisoma setoense sp. nov.

Microfocus X-Ray Computed Tomography of (Platyhelminthes: Polycladida) with an Evaluation of Histological Sections After Scanning.

Microfocus X-ray computed tomography (micro-CT) is expected to be utilized in the taxonomy of macroturbellarians that require histological technique(s) for identification, allowing nondestructive observation of the internal structures of specimens in a short time. With micro-CT, we observed a polyclad flatworm, (Schmarda, 1859), in this study. In the CT images, the main reproductive organs in the polyclad specimen were well observed, but some diagnostic characters were unclear or undetectable.

Correction to: 'Revisiting (Annelida, Parergodrilidae) in Japan, with insights into their amphi-Pacific diversification' (2024), by Natsumi Hookabe .

[This corrects the article DOI: 10.1098/rsos.231782.

Molecular Systematics and Type-material-based Redescription of Metarhadinorhynchus lateolabracis, With Taxonomic Revisions of Metarhadinorhynchus, Indorhynchus, and Neotegorhynchus (Acanthocephala: Palaeacanthocephala).

Purpose: Molecular phylogenetics has been improving the acanthocephalan systematics, yet numerous taxa remain unexplored. The palaeacanthocephalan Metarhadinorhynchus Yamaguti, 1959 and its type species M. lateolabracis Yamaguti, 1959 are such to-be-explored taxa.

Revisiting (Annelida, Parergodrilidae) in Japan, with insights into their amphi-Pacific diversification.

Polychaetes are typically found in marine environments with limited species adapting to semi-terrestrial habitats. The genus comprises interstitial polychaetes dwelling in sandy beach areas around or above the high-water line. Based on molecular data, previous studies suggested the presence of multiple cryptic species in some different localities in the world lumped together as .

Pacific marine gregarines (Apicomplexa) shed light on biogeographic speciation patterns and novel diversity among early apicomplexans.

Gregarines are the most biodiverse group of apicomplexan parasites. This group specializes on invertebrate hosts (e.g.

Capropodocerus, a new genus in Podoceridae (Crustacea: Amphipoda) from Japan, with descriptions of two new species.

We establish the new podocerid genus Capropodocerus gen. nov. for the two new species Capropodocerus tagamaru gen.

Morphological and molecular characterization of a new species of the genus Echinorhynchus Zoega in Müller, 1776 (Acanthocephala: Echinorhynchidae) parasitizing the rock greenling Hexagrammos lagocephalus (Pallas) (Scorpaeniformes: Hexagrammidae) from eastern Hokkaido, Japan.

A new species of marine-fish-parasitizing echinorhynchid palaeacanthocephalan, Echinorhynchus sasakiae sp. nov., is described based on material from the intestine of the rock greenling Hexagrammos lagocephalus (Pallas) obtained in two localities (Akkeshi and Nemuro) in Hokkaido, northern Japan.

sp. nov., an Interstitial Polyclad Flatworm Showing a Wide Distribution along Japanese Coasts.

We establish a new interstitial polyclad species, sp. nov., based on specimens collected from coarse-sandy habitats in three Japanese main islands (Hokkaido, Honshu, and Shikoku) along the coasts of the Pacific Ocean and the Sea of Japan.

The Bryozoan (Cheilostomata: Calloporidae) in Northern Japan Includes Multiple, Co-occurring Cryptic Species.

The cheilostome bryozoan is common in the rocky intertidal habitat from southeastern Alaska to northern Japan. We examined its phylogeography by analyzing 576 bp of the mitochondrial COI () gene sequenced for 298 colonies from 16 localities in northern Japan. A maximum-likelihood phylogeny detected three main clades (A, B, C).

Species description and phylogenetics of Oerstedia fuscosparsa sp. nov. (Nemertea: Monostilifera: Oerstediidae) from Japan.

We provide a morphological and molecular-based description of the eumonostiliferous hoplonemertean Oerstedia fuscosparsa sp. nov. based on two specimens dredged from a depth between 11 and 18 m off Kouyatsu, Tateyama, Chiba, Japan.

Molecular Analysis of MgO Nanoparticle-Induced Immunity against Fusarium Wilt in Tomato.

Fusarium wilt, caused by f. sp. (FOL), is a devastating soilborne disease in tomatoes.

Systematic position of the genus Metacanthocephalus Yamaguti, 1959 (Palaeacanthocephala: Echinorhynchida) inferred from molecular evidence, with a redescription of Metacanthocephalus ovicephalus (Zhukov, 1960).

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.

Reversible shifts between interstitial and epibenthic habitats in evolutionary history: Molecular phylogeny of the marine flatworm family Boniniidae (Platyhelminthes: Polycladida: Cotylea) with descriptions of two new species.

Tiny animals in various metazoan phyla inhabit the interstices between sand and/or gravel grains, and adaptive traits in their body plan, such as simplification and size reduction, have attracted research attention. Several possible explanations of how such animals colonized interstitial habitats have been proposed, but their adaptation to this environment has generally been regarded as irreversible. However, the actual evolutionary transitions are not well understood in almost all taxa.

Descriptions of two new species of Armatoplana (Polycladida: Stylochoplanidae) from the coasts of Japan, with their phylogenetic positions in Leptoplanoidea.

We describe two new species of Armatoplana Faubel, 1983, namely, A. albomaculata sp. nov.

First record of the decapod-egg predator Ovicides paralithodis (Nemertea, Carcinonemertidae) from the snow crab Chionoecetes opilio (Decapoda, Brachyura).

The carcinonemertid monostiliferan Ovicides paralithodis Kajihara and Kuris, 2013 was originally described as an egg predator of the red-king crab Paralithodes camtschaticus (Tilesius, 1815) in the Sea of Okhotsk, the Bering Sea, and the Gulf of Alaska. In the present study, several carcinonemertid specimens were obtained from the egg mass of the snow crab Chionoecetes opilio (O. Fabricius, 1788) in the Sea of Japan.

Description of sp. nov. (Nemertea: Palaeonemertea) from Sagami Bay, Japan.

The palaeonemertean genus Renier, 1804 currently harbors 35 species inhabiting the intertidal to the hadal zones. During a faunal survey in Sagami Bay, Japan, a single specimen of undescribed tubulanid having uniformly pale-colored body with a single dark-colored stripe on the dorsal surface was collected by dredging at depths of 116-211 m. Based on the body coloration and some anatomical features, it can be differentiated from the 35 congeners and is thus described herein as sp.

Lineid Heteronemerteans (Nemertea: Pilidiophora) from Sagami Bay, Japan, with Some Proposals for the Family-Level Classification System.

We performed molecular phylogenetic analyses using nucleotide sequence data from five genes (16S rRNA, cytochrome oxidase subunit I, 18S rRNA, 28S rRNA, histone H3) determined from 36 specimens representing 25 (10 named, 15 unnamed) species of lineid heteronemerteans collected in Sagami Bay, Japan, along with other sequences obtained from public databases. External features of the 25 species are briefly described and illustrated. Takakura, 1898 is transferred to Huschke, 1830.

Sinking Down or Floating Up? Current State of Taxonomic Studies on Marine Invertebrates in Japan Inferred from the Number of New Species Published between the Years 2003 and 2020.

Taxonomic studies on marine invertebrates have been prominent in Japan since the 19th century. Globally, taxonomy was reported to have been in recession since the early 21st century, but it is not clear if it is still in hardship or is making a recovery in recent years in Japan. In order to comprehend the status quo of taxonomic studies on marine invertebrates in Japan, we compiled a list of marine invertebrate species newly described from the exclusive economic zone of this country during the period between 2003 and 2020 and investigated trends by making comparisons of higher taxa and academic journals in terms of the numbers of new species and taxonomic authors.

Description of a New Species of the Marine Flatworm (Platyhelminthes: Polycladida) and its Three Known Congeners from Misaki, Japan, with Inference of Their Phylogenetic Positions within Prosthiostomidae.

The present study provides morphological descriptions of four species of (Polycladida, Prosthiostomidae)- Kato, 1937; sp. n.; cf.

Morphological and molecular characterization of the marine-teleost parasitizing acanthocephalan Echinorhynchus hexagrammi (Syndermata: Palaeacanthocephala) from a new host, Liparis sp. (Actinopterygii: Scorpaeniformes).

Originally described from the masked greenling Hexagrammos octogrammus (Pallas, 1814), the palaeacanthocephalan Echinorhynchus hexagrammi Baeva, 1965 has so far been known from seven species in six families of marine teleosts distributed in the Sea of Okhotsk off Sakhalin and in the Northwestern Pacific off Hokkaido, Japan. In this study, we examined the phylogenetic position of E. hexagrammi based on material obtained from the intestine of an unidentified snailfish, Liparis sp.

and comb. nov. (Nemertea: Heteronemertea) are Sister Species with Prezygotic Isolating Barriers.

The heteronemertean (Takakura, 1898) was originally described as based on material from Misaki, Japan. Although this species was regarded as consisting of two color variants, purple and brown-yellow, the identity of these variants has never been examined based on topotypes. In this study, we performed a multi-locus phylogeny reconstruction, species delimitation analyses, and cross-fertilization experiments to examine the species status of Takakura's original taxon concept consisting of these color variants.

Higher classification of the Monostilifera (Nemertea: Hoplonemertea).

The nemertean order Monostilifera consists of 594 species in 127 genera and is distributed worldwide. Within the Monostilifera, two suborders have been recognized, Cratenemertea and Eumonostilifera. Within the latter, two, unranked clade names, Oerstediina and Amphiporina, were recently proposed without formal taxonomic definition.

Lacydoniidae (Annelida) Off the Coast of North-eastern Japan: A Description of sp. nov.

sp. nov. (Annelida, Lacydoniidae) is described based on material found in sediments collected off the Pacific coast of northern Honshu, Japan, at depths of 262 m and 407 m.