Emprostiotrema contains just 3 species: E. fusum, E. kuntzi and E. sigani. As adults, all 3 species infect rabbitfishes (Siganidae: Siganus). New collections from 11 species of Siganus from northern Australia, Indonesia, New Caledonia, French Polynesia, Palau and Japan enabled an exploration of species composition within this genus. Phylogenetic analyses demonstrate a deep distinction between 2 major clades; clade 1 comprises most of the sequences of specimens from Australia as well as all of those from Japan, Palau and New Caledonia and clade 2 comprises all sequences of specimens from French Polynesia, 2 sequences from Australia and the single sequence from Bali. In all analyses, both major clades have genetic structuring leading to distinct geographic lineages. Morphologically, specimens relating to clades 1 and 2 differ but overlap in body shape, oral sucker and egg size. Principle component analysis shows a general (but not complete) separation between specimens relating to the 2 clades. We interpret the 2 clades as representing 2 species: clade 1 is identified as E. fusum and is reported in this study from 10 species of siganids from Australia, Japan, Palau and New Caledonia; clade 2 is described as E. gotozakiorum n. sp., for all specimens from French Polynesia and rare specimens from Australia and Indonesia. We recognize E. sigani as a junior synonym of E. fusum. Although species of Emprostiotrema occur widely in the tropical Indo-Pacific, they have not been detected from Ningaloo Reef (Western Australia), the southern Great Barrier Reef or Moreton Bay (southern Queensland).

Mylonchulus laocaiensis sp. n. recorded from Vietnam, is described and illustrated, and its phylogenetic relationship within the Mylonchulidae family and Mononchida order are analysed. The new species is characterized by medium body size (L = 1.0–1.5 mm); buccal cavity goblet shaped, 26–29 × 14–16.5 μm or 1.8 (1.7–1.9) times as long as wide; posterior position of dorsal tooth apex (79%–88% from the base of buccal cavity); a small subventral tooth present on subventral wall; pars refringens vaginae with faint and small (2.5 × 1.7 μm) teardrop-shaped pieces, short pars distalis vaginae; male with short spicules (54–57 μm) with rounded head. The molecular data (18S and 28S rDNA) are provided for the new species.

Aplectana hylambatis (Baylis, 1927) is a widespread nematode in South America that infects different species of anurans from different families. Although the morphology of this species shows intraspecific variations and is well studied, A. hylambatis does not have genetic characterisation. Therefore, the present study aimed to provide the first genetic characterisation of this parasite, based on 18S and 28S rDNA sequences, as well as to evaluate its phylogenetic position in the family Cosmocercidae. The present specimens showed no major morphological variations and were assigned to A. hylambatis mainly based on the shape of spicules and the presence of mamelon-like structures slightly anterior to the vulva. The genetic characterisation confirmed the close relationship between A. hylambatis and other cosmocercids, and the 28S sequences were more informative for phylogenetic reconstruction, especially for those relationships at higher and intermediate levels. Aplectana hylmabatis was in a basal position within a clade formed by other congeners and species of Cosmocerca. The geographic origin may have influence in the divergence process of Aplectana spp. and genus was non-monophyletic and closely related to Cosmocerca, similar to previous findings. The present results will be useful for future studies on the phylogeny of Cosmocercidae, since several genera and species in this family still lack genetic characterisation. Furthermore, the 28S sequences can be useful in genetic studies of A. hylambatis populations, since this species appears to have phenotypic variations.

During our research programme about mussel spat in Amsa Bay, we found some specimens of Hesione sicula delle Chiaje, 1830 and noted as the first record for Mediterranean Moroccan coasts and for the Mediterranean coastlines of North Africa. Five specimens of this species were collected for the first time in the Amsa shellfish farm on October 30, 2021, and we provide some characteristics and illustrations for the species. This new record from the bay contributes to the Polychaeta list of North Africa and expands the geographical distribution range of species within the Mediterranean Sea.

Tanaidaceans have a worldwide distribution, with 36 families, 316 genera, and 1575 extant species described. This study aimed to compile the resulting taxonomic information for Brazilian waters obtained to produce the available online catalogue Taxonomic Catalogue of the Brazilian Fauna. Results show 63 species described for Brazilian waters: 30 Apseudomorpha and 33 Tanaidomorpha, distributed in 46 genera and 18 families. For apseudomorphan, Kalliapseudidae is the most diverse family (12.7%), followed by Apseudidae and Parapseudidae (9.5% each). For tanaidomorphan, Typhlotanaidae is the most diverse (15.9%) followed by Leptocheliidae (9.5%) and Tanaididae (7.9%). In Brazilian waters, more than 60% of Tanaidacea species are distributed in shallow waters (42 species; 63.6%), including continental areas, and about 1/3 are recorded from deep-sea (24 species; 36.4%). Southeast Region of Brazil holds most records with 46 occurrences, followed by the Northeast Region with 19 occurrences. Our results highlight the increasing number of publications and new Brazilian tanaids species in the last 15 years, and this is directly correlated to where specialists in alpha-taxonomy, systematics/phylogeny, and ecology are based in. Our current dataset also indicates an important aspect regarding the lack of taxonomic experts of Tanaidacea worldwide, but especially in Brazil. This study gives an overview of all the information that may help elucidate future research on the taxonomic diversity of tanaidaceans in Brazil, thus it is expected that this may encourage further studies and specialists for the group.

Three fish blood flukes (Aporocotylidae Odhner, 1912) infect mullets (Mugiliformes: Mugilidae): Cardicola mugilis Yamaguti, 1970 and Plethorchis acanthus Martin, 1975 infect striped mullet, Mugil cephalus Linnaeus, 1758 in the Central Pacific Ocean (Hawaiian Islands) and Brisbane River (Australia), respectively; Cardicola brasiliensis Knoff & Amato, 1992 infects Lebranche mullet, Mugil liza Valenciennes, 1836 from the Southwestern Atlantic Ocean (Brazil). White mullets were cast-netted from the mouth of Deer River, a coastal saltmarsh of Mobile Bay, in the north-central Gulf of Mexico and examined for blood fluke infections. Specimens of Mugilitrema labowskiae Warren & Bullard n. gen., n. sp. were found infecting the endocardial surface and inter-trabecular spaces of the atrium, ventricle, and bulbous arteriosus. The new genus and species differ from all other aporocotylids by having the combination of two post-caecal testes, a uterus with straight ascending and descending portions, and a common genital pore. The 28S analysis recovered the new species and P. acanthus as sister taxa and Aporocotylidae as monophyletic. Carditis associated with intense infections comprised endocardial hyperplasia, resulting in a thickened cardiac endothelium. Probable dead or deteriorating eggs in the myocardium were encapsulated by granulomas composed of epithelioid histiocytes. Live eggs infected the afferent artery of gill filaments and were associated with varied hyperplasia of the overlying epithelium and haemorrhaging from the afferent artery in high-intensity infections. The new species is the first aporocotylid infecting a mullet from the northwestern Atlantic Ocean and only the second description of demonstrable endocarditis attributed to an adult fish blood fluke infection.

Rhabdias are lung-dwelling parasites of anurans and some reptiles. Currently, 93 species are known to exist worldwide. The identification of Rhabdias species is based mainly on morphological traits of hermaphroditic females that generally have a very conserved morphology. However, different approaches, such as the combination of morphological, molecular, and ecological data, have provided advances in identifying and delimiting rhabdiasid species. Here, we describe a new species of Rhabdias from the south of Brazil, with morphological and molecular data. The new species is distinguished from its congeners by having an elongated body, evident cephalic dilation, larger buccal capsule, and large esophagus. In addition to morphological characteristics, we observed significant genetic divergence among the cytochrome oxidase subunit I (COI) sequence of the new species and the closest available sequence, Rhabdias fuelleborni (10.24%–10.87%). Furthermore, phylogenetic reconstructions based on the COI gene indicated that the new species represents a different lineage, constituting an outgroup of the species complexes Rhabdias cf. stenocephala and Rhabdias fuelleborni with Rhabdias sp. 4. Thus, Rhabdias megacephala is the 24th nominal species of the Neotropical region, the 14th Brazilian, and the fourth species described from south of Brazil.

The introduction of non-native species is a constant concern around the world since it represents one of the main threats to biodiversity, impacting negatively on native populations, some of them with commercial importance. Hence, monitoring these introductions is fundamental to the management and conservation of the biodiversity of a region. Herein, we report the presence of Moerisia cf. inkermanica in the ballast water of oil tankers loaded at the Cayo Arcas oil terminal. The taxonomy of Moerisia members is uncertain due to the lack of comprehensive morphological descriptions and the few molecular data available. So, we provide a detailed morphological comparison among its congeners. The taxonomic identity of the specimens was determined based on the length of the perradial lobes of the manubrium, the number of tentacles, and the features of their nematocyst rings. Some Moerisids are considered invasive in different localities of the world. However, this genus had not been reported in coastal ecosystems of the Gulf of Mexico over the years until now. Sampled tankers came from different ports of the region, mainly from the northern Gulf of Mexico. Therefore, we encourage systematic monitoring of these ecosystems to recognize the establishment of this species as invasive in the region, know its population dynamics over time, and evaluate the possible ecological impacts that could exert on native populations.

Aptrootia khaoyaiensis Polyiam & Lücking is described as new to science from dry dipterocarp forest in central Thailand, based on morphological assessment and sequence data of the mitochondrial small subunit (mtSSU). The new species is characterized by a corticolous habit, a corticate thallus, ascomata typically immersed in the thallus, with a brown to blackish ostiolar region, an inspersed hamathecium, and dark brown, muriform ascospores occurring 1–2 per ascus. Phylogenetic analyses support placement of the new species in Aptrootia; it is morphologically close to A. elatior but differs in the smaller ascospores and the inspersed hamathecium.

Cylicospirura Vevers, 1922 is a genus of gastrointestinal spirurid nematodes parasitizing mainly felid but also canid, hyaenid and dasyurid hosts. Presently, 11 species are recognized worldwide, of which 4, Cylicospirura subaequalis, Cylicospirura felinea, Cylicospirura crocutae and Cylicospirura pardalis, have been recorded from African carnivores. In the present study, we describe Cylicospirura phiri n. sp. from hyaenas, namely Crocuta crocuta (type host) in Zimbabwe and Hyaena hyaena in Cameroon. The new species is the second species in the genus with bicuspid teeth. Furthermore, it can be distinguished from its congeners by a combination of characters, such as the absence of accessory teeth, the length and shape of the muscular oesophagus, position of the nerve ring, deirids and excretory pore in relation to the muscular oesophagus, the position of the vulva, spicule length and the shape of the female tail. Additionally, based on new material, detailed morphological descriptions are provided for C. crocutae and C. pardalis whose original descriptions were based on fragmented material. The material from Felis lybica, currently deposited as C. subaequalis, is described as C. felinea. First-time scanning electron micrographs are presented for the 4 species confirmed in African carnivores.

Maastrichtian scleractinian corals from 94 localities in 26 Maastrichtian regions world-wide with strata of that age are taxonomically and palaeobiogeographically evaluated. A total of 205 taxa, belonging to 116 genera and 37 families, are included in the present study. Most coral taxa have been recorded from non-reefal environments. A significant majority of these taxa (genera = 70.7%; species = 75.6%) appear to have been endemic during the Maastrichtian. The Maastrichtian coral fauna is dominated by solitary and cerioid-plocoid forms (both accounting for 41 genera = 70%), having mainly medium- and large-sized corallites. The most diverse coral assemblages are those that have been recorded from arid (Jamaica: 63 species, Mexico: 29 species), warm-temperate (the Netherlands-Belgium: 32 species) and tropical regions (Iran: 27 species). The occurrence of Cunnolites polymorphus (Goldfuss) is newly recorded for the Netherlands (southern Limburg). Compared to the microstructural composition of the coral fauna of the lowermost Cretaceous (Berriasian; 91% of the species and 83% of the genera belonged to previously established microstructural groups), in the Maastrichtian, corals belonging to previously established microstructural groups were of minor importance (genera = 26%; species = 29.3%). The majority of Maastrichtian scleractinian taxa (both solitary and colonial) from the type area of the Maastrichtian Stage in the southeast Netherlands and northeast Belgium are illustrated.

Three new species of thelotremoid lichens, Ampliotrema subglobosum Poengs. & Lumbsch, Ocellularia lichexanthonica Poengs. & Lumbsch and O. saxiprotocetrarica Poengs. & Lumbsch, are described and illustrated based on specimens from southern Thailand. Ampliotrema subglobosum is similar to A. globosum but differs by having larger ascospores with more septa. Ocellularia lichexanthonica differs from O. subdolichotata in ascomata diameter and by containing lichexanthone. Ocellularia saxiprotocetrarica is similar to O. gentingensis in ascospore length and the number of ascospore septa but has narrower ascospores and contains protocetraric acid. Fifteen species are reported for the first time for Thailand: Austrotrema bicinctulum (Nyl.) I. Medeiros et al., Baeomyces heteromorphus Nyl. ex C. Bab. & Mitt., Chapsa niveocarpa Mangold, Chiodecton sphaerale Ach., Erythrodecton malacum (Kremp.) G. Thor, Lecanora subjaponica L. Lü & H. Y. Wang, Leucodecton subcompunctum (Nyl.) Frisch, Myriotrema concretum (Fée) Hale, M. neoterebrans Frisch, Ocellularia khasiana (Patw. & Nagarkar) Kraichak et al., O. upretii S. Joshi et al., Pseudotopeliopsis scabiomarginata (Hale) Parnmen et al., Sulzbacheromyces sinensis (R. H. Petersen & M. Zang) Dong Liu & Li S. Wang, Thelotrema diplotrema Nyl., and T. isidiophorum (Kremp.) Zahlbr. Ampliotrema globosum (Hale) Poengs. & Lumbsch is proposed as a new combination. The genus Erythrodecton G. Thor is a new genus for the lichen flora of Thailand.

As part of a parasitological survey, several specimens of two new monopisthocotylean species, Neotetraonchus celsomanueli sp. nov. and N. peruvianus sp. nov. (Dactylogyridea, Dactylogyridae), were collected from the gill filaments of the Peruvian sea catfish Galeichthys peruvianus (Siluriformes, Ariidae) off Puerto Pizarro, Tumbes region, Peru. Neotetraonchus celsomanueli sp. nov. is characterised by an MCO with a T-shaped distal end and an accessory piece that is ribbed and expanded proximally with a worm-shaped termination. Neotetraonchus peruvianus sp. nov. is typified by its MCO, which has a sledgehammer-shaped distal end and an accessory piece with a claw-shaped distal end. Additionally, N. peruvianus sp. nov. is characterised by its jellyfish-shaped onchium. A partial 28S rDNA sequence was obtained from N. celsomanueli sp. nov., and a phylogenetic analysis was conducted. This analysis revealed the phylogenetic position of Neotetraonchus celsomanueli sp. nov. within a clade comprising monopisthocotylean parasites of diadromous and marine ariid catfishes, including Hamatopeduncularia spp., Chauhanellus spp., Thysanotohaptor Kritsky, Shameem, Kumari & Krishnaveni, 2012, and Neocalceostomoides spinivaginalis Lim, 1995. This finding brings the number of known Neotetraonchus species to seven and represents the first described Neotetraonchus species infecting marine catfishes from Peru.

Two new species of the genus Sectonema found in northern Iran are characterized, including morphological descriptions and molecular (18S-, 28S-rDNA) analyses. Sectonema tehranense sp. nov. is distinguished by its 7.22 – 8.53 mm long body, lip region offset by constriction and 24 – 31 μm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, mural tooth 15.5 – 17 μm long at its ventral side, neck 1091 – 1478 μm long, pharyngeal expansion occupying 61 – 71% of the total neck length, female genital system diovarian, uterus simple and 3.9 – 4.2 times the corresponding body diameter long, transverse vulva (V = 49 – 59), tail short and rounded (44 – 65 μm, c = 99 – 162, c’ = 0.6 – 0.8), spicules 111 – 127 μm long, and 7 – 10 spaced ventromedian supplements with hiatus. Sectonema noshahrense sp. nov. displays a 4.07 – 4.73 mm long body, lip region offset by constriction and 23 – 25 μm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, odontostyle 14 – 14.5 μm long, neck 722 – 822 μm long, pharyngeal expansion occupying 66 – 68% of the total neck length, female genital system diovarian, uterus simple and 2.4 – 2.7 times the corresponding body diameter long, transverse vulva (V = 54 – 55), tail convex conoid (39 – 47 μm, c = 91 – 111, c’ = 0.8 – 0.9), spicules 82 μm long, and seven spaced ventromedian supplements with hiatus. Molecular analyses confirm a maximally supported (Epacrolaimus + Metaporcelaimus + Sectonema) clade and a tentative biogeographical pattern, with sequences of Indolamayan taxa forming a clade separated from those of Palearctic ones. Parallel or convergent evolution processes might be involved in the phylogeny of the species currently classified under Sectonema. This genus is certainly more heterogeneous than previously assumed.

Hexamermis zirabi sp. n., recovered from a natural habitat of Mazandaran province, north of Iran, is described based on morphological and molecular data. The new species is characterized by its six cephalic papillae; cuticle with distinct cross fibers; conoid or sharply tapered head; mouth terminal; six hypodermal cords; J-shaped vagina oriented to the anterior end of body; uterus with Z-organs or sclerotized bodies; tail similar in both sexes and bluntly rounded; spicules paired, separate, slightly curved, shorter than body width at cloaca, with rounded tip; and male genital papillae arranged in five rows. In addition to the morphological study, molecular phylogenetic analyses using a partial large subunit (28S D2-D3) were also performed, and the new species formed a highly supported (1.00% Bayesian posterior probability (BPP)) clade with Hexamermis popilliae.

Nine hundred and ninety-two (992) specimens of Pseudocyclops lerneri Fosshagen, 1968 (Copepoda: Pseudocyclopidae) were collected from the largest South Atlantic coral reef, Abrolhos bank (17°20′–18°10′S; 38°35′–39°20′W). Specimens were distinguished from other Pseudocyclops spp. by a close examination of the female and male fifth leg. This is the first record of the family Pseudocyclopidae in the South Atlantic. We further indicate that the low number of studies on this species, and as a consequence, the poorly understood ecology of Pseudocyclopidae may be caused by the use of inadequate sampling methods, indicating the use of demersal-focused samplers, such as emergence traps as an alternative to the sampling of these bottom-dwelling copepods.

Two new species of the genus Lecidella, one with a North American-maritime Antarctic distribution and one with a so far exclusively southern South American-maritime Antarctic distribution, are described using molecular and morphological tools. Lecidella ayazii is a species growing on soil and also on mosses and has so far been found on the Antarctic Peninsula, as well as in the alpine areas of the La Sal Mountains, Utah, USA and in the Kivalliq Region (Nunavut) in the north of Canada, whereas L. drakensis occurs mainly on siliceous rocks, rarely on mosses, and has been recorded on both sides of the Drake Passage in southern Patagonia and the Antarctic Peninsula. Phylogenetic analysis of the nrITS sequence data shows that both species belong in the L. elaeochroma clade, each forming a highly supported and distinct group. Furthermore, they also differ in morphological and chemical characters from the species described so far in this clade. In addition, five further accessions were recorded from the maritime Antarctic, which were placed in the cosmopolitan and heterogeneous L. stigmatea clade, of which one could be assigned to the bipolar species L. siplei.