Laetisaria macrospora is a new species of lichenicolous Corticiaceae forming light pink to coral coloured basidiomata on Physcia adscendens and P. stellaris. The basidiomata are usually located on the lower surface of the host thallus and produce basidia with four sterigmata and relatively large basidiospores, 23–34 × 11–18 μm. Phylogenetic analyses using nuITS sequences fully support the placement of the new species in Laetisaria, a genus that is recovered as monophyletic. Laetisaria macrospora was discovered in the Massif Central (France) in lichen communities growing on branches of Juniperus and Genista at the summit of the Puy de Manson.

The nematodes isolated from three species of Chanodichthys were completely consistent with the morphological description of Rhabdochona coronacauda. We provide new morphometric data for R. coronacauda, which slightly differ from those of the original description. For the first time, we performed a phylogenetic analysis by using both primary (linear) and secondary (folded structures) sequences of the complete 18S rRNA gene for three superfamilies of Spiruromorpha. The interspecific genetic distances within the genus Rhabdochona were 0.13%–3.06% between 18 species. Rhabdochona coronacauda was sister to a sub-group consisting of the type species R. denudata, R. hospeti, R. hellichi, and R. turkestanica. The secondary structures reconstructed for 35 species of three superfamilies from the order Spiruromorpha comprised 16 conformations of the region including helix 39 and expansion segment 9, and two conformations of helix 17. Helix 39 can be used to differentiate single species or separate species groups of Rhabdochona. The structures of helix 39 in both Rhabdochonidae and Cystidicolidae with Salmonema had an identical 39a domain but differed in the 39b domain and expansion segment 9. In addition, the structure of the helix 39–expansion segment 9 domain within and between families of different superfamilies and their resolution on the phylogenetic tree in combination did not correspond to the accepted classification of spiruromorph nematodes. Helix 17 did not differ within Rhabdochona, or between Rhabdochonidae and Cystidicolidae. At the superfamily level, helix 17 can distinguish Thelazioidea, Spiruroidea, and Habronematoidea from Rhabdochonidae, and Cystidicolidae from Spirocercidae, Thelaziidae, and Pneumospiruridae.

Hydrothermal vents are known to host unique faunal assemblages supported by chemosynthetic production; however, the fauna associated with inactive sulphide ecosystems remain largely uncharacterised across the global seafloor. In November 2023, a six-rayed starfish was collected from the Semenov hydrothermal field on the Mid-Atlantic Ridge. A combination of morphological and molecular methods has confirmed the identity of this species as Paulasterias mcclaini Mah et al. 2015 (Forcipulatida: Paulasteriidae), providing the first validated record of this family in the Atlantic Ocean. We present an updated morphological description of the species, alongside phylogenetic analysis of the COI, 16S, 12S, and H3 genetic markers. The biogeography of the family is discussed, and previously published records amended.

Distinguishing between Stomylotrema bijugum and S. vicarium is challenging due to their phenotypic plasticity. In this study, adult specimens were recovered from 9 host species in the Mexican tropical lowlands. To explore the morphological differences, 32 morphological characteristics were evaluated in 54 specimens. Linear discriminant analysis provided enough evidence to differentiate the 2 species. Additionally, a principal component analysis (PCA) was performed for each species. The PCA of S. bijugum revealed 3 groups separately corresponding to specimens from the 3 hosts, suggesting host-induced phenotypic plasticity, whereas the PCA of S. vicarium revealed that the specimens from 3 host species were clustered together, indicating morphometric homogeneity. To confirm the morphological differences between the 2 species of Stomylotrema, we sequenced 2 molecular markers: the D1–D3 domains of the large subunit (LSU) from nuclear DNA and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (Nad1) from mitochondrial DNA. Sequences of the LSU were aligned and compared with the LSU sequences of other congeneric species available in GenBank. Phylogenetic analyses supported the monophyly of Stomylotrema, with 2 main subclades that corresponded to S. bijugum and S. vicarium. A haplotype network was predicted with 25 Nad1 sequences, revealing the presence of 2 clusters representing the 2 species separated from each other by 98 substitutions. The current studies on S. bijugum and S. vicarium revealed new hosts and geographical regions in the Americas, suggesting that both species addressed in the current study can complete their life cycle in the Neotropical region of Mexico.

A species of acanthocephalan collected from the hindgut of Larimichthys crocea was identified as Longicollum pagrosomi Yamaguti, 1935 based on morphological characteristics. The complete mitochondrial genome of this parasite was sequenced. The mitogenome exhibited a circular structure with a total length of 14 632 bp, containing 12 protein coding genes (PCGs), 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs) and 2 major non-coding regions. The most frequently used start codon was GTG, and the most abundant amino acid was valine. The phylogenetic analyses of the mitogenome using Bayesian inference and maximum likelihood methods showed that the genus Longicollum formed a sister clade to the genus Pomphorhynchus, supporting the monophyly of Pomphorhynchus. This study reported a new host for L. pagrosomi and revealed the first complete mitogenome sequence of the genus Longicollum.

Corticolous sorediate Candelariella represent, at least in Europe, a widespread group of species, often predominant in epiphytic communities. Many specimens are challenging to identify since apothecia are generally lacking and names have been frequently misapplied in the past. Here, we studied the morphology and molecular data (ITS nrDNA sequences) of corticolous sorediate Candelariella specimens, with the aim of determining how many species occur in Europe and which names should be applied. We distinguish worldwide five taxa from this group that are widespread and currently well supported by both morphological and molecular data. These include three 8-spored species (Candelariella reflexa, C. rubrisoli and C. xanthostigmoides) and two polyspored species (C. efflorescens and Candelariella pulchella sp. nov., the latter characterized by coarser soredia, larger apothecia with a persistent proper margin and broader paraphyses tips). Four of these species (all except C. xanthostigmoides) occur in Europe. European specimens previously identified as C. xanthostigmoides belong to C. rubrisoli. Candelariella makarevichiae and C. subsquamulosa are considered synonyms of C. xanthostigmoides. Candelariella sorediosa, C. flavosorediata and C. magellanica (the latter two not reported from Europe) remain poorly known species for which molecular data is currently lacking and they require further study. Full descriptions and a key to the species discussed are provided.

Avian trypanosomes (Trypanosoma, Kinetoplastea) are successful blood parasites occurring worldwide. These parasites are usually non-pathogenic to their avian hosts, thus neglected in studies regarding their life cycles and vectors. Several families of blood-sucking dipteran insects, including mosquitoes, have been identified as vectors of avian trypanosomes. Mosquitoes have been experimentally confirmed as vectors of Trypanosoma culicavium and Trypanosoma thomasbancrofti. In this study, we describe a third species of avian trypanosomes occurring in mosquitoes, designated as Trypanosoma tertium n. sp. This species can be distinguished from related trypanosome species based on morphology and small subunit rRNA gene sequence. Two isolates of T. tertium n. sp. obtained from a mosquito and a bird host were able to infect two subspecies of laboratory Culex pipiens mosquitoes, with infection rates reaching 60% and heavy infections in 90% of positive females. In infected mosquitoes, trypanosomes occurred as long epimastigotes in the midgut and short epimastigotes and rosettes in the hindgut. Putative infectious stages were detected in the diuretic liquid of infected mosquitoes, suggesting, besides transmission through ingestion of the infected vector, a possible transconjunctival infection. Among wild mosquitoes, avian trypanosomes were detected exclusively in Cx. pipiens with 3.3% total prevalence, while T. tertium n. sp. prevalence was only 0.08% among 1128 dissected Cx. pipiens individuals. In birds, T. tertium n. sp. was detected in 8 species within which the prevalence was 1.3% (686 birds), while it was 0.3% in total (3084 birds). We discuss the relationship of the newly described T. tertium n. sp. with other mosquito-transmitted trypanosomes.

Ochetosoma heterocoelium (Travassos, 1921) was collected from the mouth and oesophagus of a pit viper, Bothrops moojeni Hoge, 1966 in São Sebastião do Paraíso Farm (21°51’48.26" S, 48°26’56.78" W), municipality of Boa Esperança do Sul, São Paulo State, Brazil. In this study, we provide the first molecular characterisation of this digenean using 28S rDNA and COI sequences, and its phylogenetic position within the Plagiorchiida is assessed. Furthermore, new morphological features are added to the diagnosis of the species, and scanning electron microscopy photomicrographs are presented. Sequences of the 28S rRNA gene of O. heterocoelium were successfully obtained and aligned with 35 digenean species belonging to Plagiorchiida. Only three congeners – O. aniarum (Leidy, 1890), O elongatum (Seo et al. 2024), and O. kansense (Crow, 1913) – have been sequenced for this molecular marker. The newly sequenced individuals of O. heterocoelium are 98.7% and 99.4% similar to O. aniarum and O. kansensis, respectively, and Ochetosoma is not recovered as a monophyletic group. Dasymetra nicolli Holl and Allison, 1935 and Lechriorchis tygarti Talbot, 1933 are nested with Ochetosoma.

As part of a broad survey of the trematodes of damselfishes (Pomacentridae) in the tropical Indo-West Pacific, zoogonids were collected from multiple localities in Australia, New Caledonia, and French Polynesia. All zoogonid specimens collected were consistent with the subfamily Lecithostaphylinae, and morphological and molecular data (ITS2 and 28S rDNA, and cox1 mtDNA) were generated for most host-locality combinations to enable an integrative species delimitation. The collection comprised three species: Deretrema stratiotes n. sp. from four species of Abudefduf Forsskål from Ningaloo Reef in Western Australia, and two species consistent with the genus Lecithostaphylus Odhner, 1911 for which Innuptacola n. gen. is proposed based on phylogenetic and morphological distinction, the type-species I. gibsoni (Cribb, Bray & Barker, 1992) n. comb. (= L. gibsoni) from six species of Abudefduf in Ningaloo Reef, Queensland and New Caledonia, and I. torquata n. sp. from 12 pomacentrid species in Ningaloo Reef, the Great Barrier Reef in Queensland, and the Gambier Islands in French Polynesia. The new collection demonstrates that some zoogonid species are geographically widespread (from the Pacific Ocean to the Indian Ocean) and can infect a broad range of hosts (multiple genera within a family), whereas others are apparently geographically restricted and exhibit higher host-specificity (fishes within a single genus).

A population of Oscheius insectivorus was recovered from inside the body of a live scarab beetle collected from natural forests of Jafar Abad village, Golestan province, and was reported from Iran for the first time. The Iranian isolate of the species is characterized by 1103–1942 μm long females with their vulva at 46.9–57.4% of the body, tail 75–118 μm long, males with spicules 60.0–74.5 μm long, gubernaculum 23.7–32.2 μm long, and infective juveniles measuring 790–985 μm long. Females and males of the recovered population had shorter body when compared with the type population. Molecular identification of the recovered population was performed using the SSU and D2-D3 expansion segments of LSU rDNA, and corresponding phylogenetic trees were reconstructed and discussed. The pathogenicity of the Iranian isolate was evaluated on the larvae and adults of the poplar leaf beetle, Chrysomela populi, and the larvae of the wax moth, Galleria mellonella, under laboratory conditions. A suspension of 200 infective juveniles per ml (IJs/ml) of the nematode was most effective against third instar larvae of C. populi, causing 75% mortality 72 hours post-exposure. In adults, mortality reached 70% at the same concentration and exposure time. For G. mellonella larvae, O. insectivorus caused 50% mortality at 200 IJs/ml within 72 hours post-exposure. The lethal concentration 50 (LC50) values of the nematode were 77.71 and 94.06 IJs/ml for third instar larvae and adults of C. populi, respectively, and 217.04 IJs/ml for fifth instar larvae of G. mellonella 72 hours post-exposure at 25°C and 60% relative humidity.

This study describes a new species of Pharyngodon Diesing, 1961 (Nematoda: Pharyngodonidae) in teiid lizards Ameivula ocellifera (Spix, 1895) (Squamata: Teiidae) from a Caatinga morphoclimatic domain in the state of Pernambuco, Brazil. Pharyngodon ameivulum n. sp., like 11 other species of the genus, features males without spicules, females with truncated eggs, and no tail spines. However, the new species is distinguished by a unique set of morphological characteristics, such as males possessing three pairs of caudal papillae, with the first pair precloacal, the second adcloacal, and the third postcloacal (arrangement 1:1:1), the second pair (adcloacal) of papillae having a bifurcated distal end, and females with lateral body alae. Molecular analysis of the 18S rDNA, 28S rDNA, and 18S + 28S concatenated sequences genes reveals that P. ameivulum n. sp. clusters with representatives of Pharyngodonidae from the genera Skrjabinodon Inglis, 1968 and Spauligodon Skrjabin, Schikhobalova & Lagodovska, 1960, forming a basal clade to the clade composed of Spauligodon spp. and Skrjabinodon trimorphi Ainsworth, 1990. These are the first phylogenetic assays to include a species of Pharyngodon.

Species of the genus Corynosoma (Acanthocephala: Polymorphida) mainly parasitize marine mammals and rarely marine birds, and are of veterinary and medical importance due to causing corynosomiasis in wildlife and humans. However, the current knowledge of the mitochondrial genomes and mitogenomic phylogeny of this group remains very insufficient. In the present study, the complete mitochondrial genomes of C. bullosum (von Linstow, 1892) and C. evae Zdzitowiecki, 1984 were sequenced and annotated for the first time. Both mitogenomes comprise 12 protein-coding genes (missing atp8), 22 tRNA genes, and 2 ribosomal RNAs (rrnS and rrnL), plus 2 non-coding regions (NCR1 and NCR2). Corynosoma bullosum has the largest mitogenome (14,879 bp) of any polymorphid species reported so far, while C. evae has the smallest (13,947 bp), except for Sphaerirostris lanceoides (Petrochenko, 1949). Comparative mitogenomic analysis also revealed the presence of distinct discrepancies in A + T content and gene rearrangement across the families Polymorphidae, Centrorhynchidae, and Plagiorhynchidae. Moreover, phylogenetic analyses based on the concatenated amino acid sequences of 12 protein-coding genes strongly supported the monophyly of the order Polymorphida and a close affinity between the families Polymorphidae and Centrorhynchidae in Polymorphida. The present mitogenomic phylogeny provides additional evidence for a sister relationship between the genera Corynosoma and Bolbosoma and demonstrated that C. evae has a closer relationship with C. villosum than C. bullosum in the genus Corynosoma.

Copepods of the genus Pennella parasitize a wide range of marine animals, including cetaceans, teleosts, and cephalopods worldwide. Their taxonomy is unclear, as there is incongruence between morphological and genetic data and incomplete species coverage. This study provides new morphological and genetic (COI) data from 23 specimens of Pennella cf. filosa (syn. P. balaenoptera) from western Mediterranean whales and a swordfish. First, their position in the phylogeny of Pennella was assessed and species delimitation revisited using all available Pennella COI sequences (n = 189), obtained from Mediterranean and north Pacific specimens from 18 host species (including multiple cetaceans and teleosts). Second, it was investigated whether the geographic location, degree of host vagility, or host taxonomic identity help explain genetic differentiation. Five distinct haplotype groups with varying genetic divergence were distinguished. Although the presence of sibling species cannot be ruled out, species delimitation methods could not find interspecific genetic differences, leaving the taxonomy of the genus unresolved. The observed genetic differentiation could not be attributed to geography or host type. This suggests that members of the genus Pennella show low specificity for definitive hosts and interoceanic dispersal mediated by some vagile definitive hosts. The use of more genetic markers for addressing these questions in the future is encouraged.

Members of Sinistroporomonorchis Wee, Cutmore, Pérez-del-Olmo & Cribb, 2020 represent a small group of trematodes belonging to the Monorchiidae Odhner, 1911 with 5 species described from mugilid hosts. Specimens consistent with the generic concept of Sinistroporomonorchis were obtained from Floridichthys polyommus (Cyprinodontidae); most of them were juveniles from 4 localities within the Yucatán Peninsula. After a detailed morphological examination including scanning electron microscopy images and a principal component analysis, the specimens collected represented a new species, Sinistroporomonorchis bolini n. sp. The new species can be differentiated by the presence of an overall large pharynx including the proportion of pharynx width to oral sucker width, a uterus arranged in 2 main lateral fields, and by presenting robust caeca. In addition, sequences of the 28S of large subunit of nuclear ribosomal RNA and cox1 of the mitochondrial DNA were obtained. Phylogenetic trees inferred from each dataset, placed all the specimens in a monophyletic clade, confirming that the isolates belonged to the same species. The new species is the sixth described for the genus Sinistroporomonorchis, the fifth described from the Yucatán Peninsula and the first described from a non-mugilid host.

Although nudibranchs are common and attractive animals, our understanding of these marine gastropods in Vietnam remains limited. Prior research has suggested that combining morphological examination with molecular analysis results in more accurate identification of nudibranchs. However, previous studies in Vietnam have typically relied solely on morphological methods for nudibranch identification. In this study, the nudibranch species Halgerda batangas was recorded in Vietnam for the first time based on both morphological and molecular approaches. Halgerda batangas was characterized by a network pattern consisting of orange lines, relatively low dorsal tubercles with red-orange caps and white basal rings, and an orange line along the foot margin. Molecular analysis corroborated the morphological findings. These results suggest that integrating morphological and molecular methods is an effective approach for identifying nudibranchs.

Species of the family Echinostomatidae use diverse gastropod taxa as first intermediate hosts. However, identification of echinostomatid larvae often proves difficult because of incomplete information on their life cycles and lack of molecular data that can link larvae to the corresponding known adults. Here, echinostomatids that were isolated from freshwater limpets in South Africa were described using light and scanning electron microscopy, and ribosomal (28S, ITS, and 18S) and mitochondrial (cox1) DNA sequences. The analyses revealed three species: Petasiger radiatus, Petasiger sp., and Echinostomatidae gen. sp. Considering the close morphological resemblance between cercariae of Petasiger spp., the current species were compared with data from literature. The results showed that cercarial size is generally unsuitable for species discrimination. The numbers of flame cells and refractile granules in the excretory system, and penetration gland cell patterns, may indicate, but do not prove species identity. Although papillary patterns were distinct between species, papillae were clearly discernible only using scanning electron microscopy and are known for only a few species. Phylogenetic reconstruction indicated that 28S rDNA sequences of Petasiger on GenBank are for P. exaeretus, P. phalacrocoracis, P. radiatus, and six unnamed species. Furthermore, the results revealed that multiple ITS rDNA and cox1 sequences labelled as Stephanoprora amurensis and P. phalacrocoracis on GenBank, are from isolates whose identities are questionable. Echinostomatidae gen. sp. could not be assigned to any currently known genus. Expansion of the genetic database of the family Echinostomatidae is necessary for the delineation of putative species and elucidation of intergeneric relationships.

Two new species in the genera Diploicia and Physcia are described from the tropical dry forest of Mexico. Both species are supported by morphological, chemical and molecular evidence. Diploicia edulis, a species heavily consumed by invertebrates, is characterized by lecanorine apothecia, a dull brown epihymenium not diffused by a green pigment (K−), a subhymenium conspicuously inspersed with oil droplets, and the diploicin chemosyndrome. We provide the first molecular evidence to support the inclusion of species with lecanorine apothecia in the genus Diploicia. Physcia ornamentalis, previously reported under the name Physcia undulata s. lat. as one of the main construction materials for the bags of a moth caterpillar species (Psychidae), is characterized by a frosted-pruinose thallus, soralia originating in the lobe sinuses, and by lacking soralia in the thalline margin of the apothecia.