Squat lobsters (Decapoda: Anomura) harbor a high diversity of symbionts, including many parasitic isopod species (Epicaridea: Bopyridae) that reside in their branchial chambers. We describe the bopyrid Parapleurocryptella poha n. sp., found infesting at least four species of squat lobsters from New Zealand. The new species displays morphological traits characteristic of the genus Parapleurocryptella Bourdon, 1972 but it is distinct from the two other described species, P. minuta Bourdon, 1972 and P. elasmonoti Bourdon, 1972, based on the form of the female head as well as male antennal segmentation, midventral tubercles, and dactyl size. Additionally, the new species is widely separated geographically and occurs on different host species compared to others in the genus. The morphology of mature male and female specimens is described, and we show a significant positive correlation of mature female parasite length with host size. The first description of the epicaridium larva of any species of Parapleurocryptella is provided and illustrated using SEM. Epicaridium larvae of the new species possess posterior external yolk sacs, a feature previously reported for larvae in only two other bopyrid genera: Pleurocryptella Bonnier, 1900 and Paragigantione Barnard, 1920. A discussion of the potential impacts of this structure to our understanding of bopyrid life cycles is provided. Additionally, the genera Pleurocryptina Nierstrasz & Brender à Brandis, 1929 and Pagurocryptella Boyko & Williams, 2010 are transferred to Pleurocryptellinae from Pseudioninae and Pseudione kossmanni is transferred to Pleurocryptella as Pleurocryptella kossmanni (Nierstrasz and Brender à Brendis, 1923) nov. comb. based on examination of the holotype.

Phanerothecium acutum sp. n., the eighth described species of the genus Phanerothecium, is characterized by a unique combination of morphological and molecular traits. Morphologically, it differs from closely related species such as P. spinatus, P. deiropedeum, and P. macrosomum by features of the male copulatory organ (MCO), anchor configuration, and ventral bar structure. Notably, P. acutum sp. n. possesses an MCO armed with delicate spines, robust and truncated anchors with a slight elevation on the shaft, and a ventral bar with expanded extremities. Molecular analyses yielded three new 18S and two partial 28S rDNA sequences. A newly developed primer (DAC18F2) markedly improved PCR success and sequencing quality for 18S amplification. Genetic distance analyses based on 18S support P. acutum sp. n. as a distinct species, with interspecific divergence from most congeners ranging from 1.4-2.0%, and intraspecific variation of 0.0-0.2%. However, its genetic similarity to Phanerothecium sp. KX981456 (0.2-0.9%) highlights the need for additional data to clarify species boundaries. Phylogenetic reconstructions based on 18S and 28S confirmed the monophyly of Phanerothecium, placed within a strongly supported clade alongside viviparous gyrodactylideans, and reaffirmed the validity of the family Oogyrodactylidae. These findings underscore the importance of integrative approaches for resolving taxonomic relationships and suggest that the genus Phanerothecium, particularly among loricariid hosts, harbors greater diversity than currently recognized.

Ixodes (Afrixodes) colboi n. sp. (Acari: Ixodidae) is described based on females ex the checkered elephant shrew, Rhynchocyon cirnei Peters (Macroscelidea: Macroscelididae) from Zambia. Females of this new species can be distinguished from other Afrotropical species of the subgenus Afrixodes Morel, 1966 by the development of carinae and scutal punctations, shape of apron and anterior projection of basis capituli, length and development of spurs on palpal segment I, coxae and trochanters, and the size and development of the syncoxae.

The genus Rondonia Travassos, 1920 comprises nematodes parasitizing teleost fishes and amphibians, but its taxonomic boundaries have long been uncertain due to limited morphological descriptions and lack of molecular data. Here, we provide an integrative taxonomic revision of Rondonia, combining light and scanning electron microscopy with molecular analyses of SSU and LSU rDNA sequences. A new species, Rondonia pardensis n. sp., is described from the intestine of Metynnis lippincottianus (Cope) (Characiformes: Serrasalmidae) in the Pardo River, Paranapanema River basin, Brazil. The new species is distinguished by the presence of a pre-bulbar excretory pore with a protruding teardrop-shaped structure covering it, the number and organization of the cloacal papillae (two pairs pre-cloacal, two pairs ad-cloacal and six pairs post-cloacal), the mouth with three bilobed lips bearing double papillae on each side arranged radially and two amphids, and a larger body size in comparison to its congeners. Phylogenetic analyses confirm its placement within Atractidae and support the monophyly of Rondonia. Based on morphological and molecular evidence, we propose a new taxonomic combination for specimens analysed by Cavalcante et al. (2016), herein reassigned as Rondonia xapuriensis nom. nov. We also examined the type material of Rondonia rondoni deposited by Travassos (1920) using SEM, confirming diagnostic features and recording additional characters that contribute to an updated morphological characterization of the species. In light of these findings, we propose an amended generic diagnosis for Rondonia that reflects its phylogenetic coherence and morphological consistency, and also a key for the identification of the Rondonia species. This study expands the known diversity of the genus, clarifies historical taxonomic uncertainties, and emphasizes the importance of integrative approaches for resolving the systematics of Atractidae.

We determined the complete mitochondrial (mt) genome of a species of Plagiorchiidae, obtained from Lymnaea stagnalis snail collected at Lake Chany, western Siberia. The cercariae were morphologically close to Opisthioglyphe ranae (Frölich, 1791), but the species identification is still pending. The mitogenome is 13,849 base pairs in length. This genome includes 12 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and one non-coding region. Notably, 20 tRNA genes produce transcribed products with conventional cloverleaf structures, while two tRNA genes have unpaired D-arms. The gene atp8 is absent, and the remaining genes are transcribed in the same direction. The A + T content of the Plagiorchiidae gen. mt genome is 65.64%. The complete mtDNA of Plagiorchiidae gen. is shorter than that of all other related xiphidiate species compared in this study. Phylogenetic analysis based on the whole mitogenome revealed that Plagiorchiidae gen. clusters closely with species from the genera Plagiorchis and Glypthelmins. Additionally, the analysis of the 28S rRNA gene indicated that it belongs to Plagiorchiidae and is particularly close to Dolichosaccus (syn. Lecithopyge). This study reports the complete mitochondrial genome of Plagiorchiidae gen., providing a valuable resource of molecular markers for future research on the taxonomy, population genetics, and systematics of the family Plagiorchiidae.

Oothecae of three species of praying mantis belonging to genera Humbertiella Saussure, Leptomantella Burmeister and Odontomantis Saussure from Kerala were collected and reared. Parasitisation of eupelmid and torymid (Hymenoptera: Eupelmidae, Torymidae) parasitoids on mantid oothecae with species level identification are reported for the first time from India. Bharatagrion gen. nov. is newly described within Podagrionini (Torymidae) with type species B. keralense sp. nov. attacking oothecae of Leptomantella parva (Werner) (Mantodea, Leptomantellidae) from Kerala. Further three species, Eupelmus gibsoni Binoy & Sureshan sp. nov. (Eupelmidae), Palmon humbertiellophaga Binoy & Sureshan sp. nov., and Podagrion grisselli Binoy & Sureshan sp. nov.: (Torymidae) are described with illustrations. Type images of Palmon orchesticus (Masi), Podagriomicron wayanadense Narendran & Mercy, and Podagrion keralensis Narendran are illustrated for the first time.

We describe Catadiscus marielaosornae Cajiao-Mora and Bullard n. sp. (Diplodiscidae) from the intestine of Peters' thin-toed frog, Leptodactylus petersii (Steindachner) (Anura: Leptodactylidae) from the Yahuarcaca Lake System, Colombia. We assigned our specimens to Catadiscus Cohn, 1904 because they have a smooth-surfaced, pyriform body, centrally-constricted ventro-terminal acetabulum that lacks an accessory sucker, pharynx with extramural sacs, oesophageal bulb, and single testis. The new species differs from all but Catadiscus rodriguezi Caballero, 1955, Catadiscus marinholutzi Freitas and Lent, 1939, and Catadiscus propinquus Freitas and Dobbin, 1956 by having a vitellarium that is confluent anteriorly (vs. two non-confluent fields). It differs from the aforenamed congeners by having a ventral common genital pore that opens anterodextral to the oesophageal bifurcation, round vitelline follicles that become confluent anterior to the testis, and a 1: 2-3 ratio of acetabulum: testis width. Our 28S phylogenetic analysis recovered the new species sister to C. marinholutzi, and Diplodiscidae as paraphyletic, with Catadiscus sister to a clade comprising a sequence ascribed to Chiorchis fabaceus (Diesing, 1838) Fischoeder, 1901 (Cladorchiidae), and sequences of three species of Diplodiscus Diesing, 1836. The species description herein includes several features pertaining to the acetabulum, female genitalia, and excretory system that could comprise useful character states with which to more readily classify and diagnose diplodiscid species and genera. To our knowledge, this is the first record of a digenean infecting Peters' thin-toed frog, and it is also the first record of any parasite infecting any ditch frog (Leptodactylus spp.) from Colombia.

A new species, Pseudocharopinus tenshken n. sp., is described and illustrated as a parasite of juvenile Squalus acanthias from Argentine waters in the South Atlantic. Although morphologically similar to Pseudocharopinus bicaudatus, a species widely distributed on the same host, distinct morphological differences are evident. The new species differs from P. bicaudatus in its dorsal shield, which is more elongated and has more developed sclerites. Additionally, the cephalothorax of the new species reaches 82% of the trunk length, whereas it is shorter in P. bicaudatus. In contrast, the maxilla in P. bicaudatus extends up to 65% of the trunk length, while in P. tenshken n. sp., it reaches 76% of the trunk length. These morphological distinctions are supported by a genetic divergence of 17% from P. bicaudatus. In the COI phylogenetic tree, a strongly supported clade is observed, consisting of (Pseudocharopinus malleus (P. bicaudatus + Lernaeopoda bivia)). Then, Salmincola spp. appears in a clade with low support, followed by Pseudocharopinus pillai. Later, another strongly supported clade includes (Pseudocharopinus tenshken n. sp. (Brianella corniger + Pseudocharopinus pteromylaei)). Based on our results, the genus Pseudocharopinus should be considered non-monophyletic. These findings suggest that at least two independent Lernaeopodid infection events occurred in chondrichthyans.

The present study aimed to report monogenoids parasitizing the gills of two species of piranhas from the state of Maranhão, Brazil: Pygocentrus nattereri Kner, and Serrasalmus rhombeus (Linnaeus). Fifty specimens of P. nattereri were caught in the Lake "Grande" in the municipality of São Bento, and 50 specimens of S. rhombeus were caught in the main channel of the Pericumã River, municipality of Pinheiro. Fourteen species of dactylogyrids were found parasitizing the gills of P. nattereri and S. rhombeus. Of the 14 species identified, 11 were found in P. nattereri: Amphitecium calycinum Boeger & Kritsky, 1988, Amphitecium camelum Boeger & Kritsky, 1988; Amphitecium falcatum Boeger & Kritsky, 1988; Amphitecium junki Boeger & Kritsky, 1988; Amphithecium sp.; Anacanthorus sp. 1; Anacanthorus jegui Van Every & Kritsky, 1992; Anacanthorus mesocondylus Van Every & Kritsky, 1992; Anacanthorus reginae Boeger & Kritsky, 1988; Anacanthorus sciponophallus Van Every & Kritsky, 1992 and Anacanthorus thatcheri Boeger & Kritsky, 1992. Five species were found in S. rhombeus: Am. calycinum; Am. falcatum; Anacanthorus amazonicus Van Every & Kritsky, 1992; A. maranhensis n. sp. and Notozothecium sp. Anacanthorus sp. 1 differs from its congeners by the morphology of the MCO, which is a flat tube with sclerotized walls and pointed terminations at both ends. Anacanthorus maranhensis n. sp. differs from its congeners by the morphology of the MCO, which is a trough-shaped tube. This study increases the number of reported dactylogyrids from P. nattereri to 28, and to 26 for S. rhombeus.

A nematode diversity survey in Mizoram, India led to the recovery of a known species of the order Mononchida (Animalia: Nematoda). Upon investigation, the species was identified as Iotonchulus longicaudatus (Mononchida: Iotonchidae) based on morphology and morphometrics. Iotonchulus longicaudatus can be characterized by its robust body, tubular buccal cavity with dorsal tooth positioned at midway of buccal length, non-denticulate subventral buccal wall, tuberculated pharyngo-intestinal junction, mono-prodelphic female genital system, filiform tail with well-developed caudal glands and spinneret. Molecular data including the 18S and D2-D3 expansion segment of 28S rDNA sequences were generated for the first time for this species and were further utilized to determine its phylogenetic relationship with other mononchs.

A second species of "tongue-eaters," the cymothoid isopod Cymothoa facimar sp. nov., is described from the coasts of Sinaloa on the Mexican Pacific coast. Twenty-seven females and five males of the new species were collected from the oral cavity of the snappers Lutjanus peru and L. aratus caught for sale in Mazatlán fish markets. The new species is morphologically similar to C. exigua, the previously known species reported from the Eastern Pacific, in general shape of body, cephalon, the anterior pereonites, pereopods and pleotelson; however, they can be easily differentiated because adult females of the new species are larger and slender than those of C. exigua and because they show differences in the dorsal surface of pereonites, the shape of the seventh pereonite and cephalon and the relative size of exopodite and endopodite of the uropods. The new species is morphologically similar to C. exigua, the only species of Cymothoa described so far from the Eastern Pacific, particularly in the general shape of the body, cephalon, anterior pereonites, pereopods, and pleotelson. Nonetheless, it can be readily distinguished from C. exigua by several diagnostic features: adult females attain larger body sizes and exhibit a slenderer morphology especially in the ovigerous females; additionally, differences are present in the dorsal sculpturing of the pereonites, the shape of the sixth and seventh pereonites, and the relative proportions of the exopodite and endopodite of the uropods. Cymothoa facimar sp. nov. resembles C. excisa, a species reported from the western Atlantic. Still, the two species can be differentiated by the relative length of the fourth pereonite, which is more prominent in the Atlantic species. The new species is described herein, and a discussion on the status of C. exigua is presented in reports from other regions of the Eastern Pacific.Zoobank registration: http://zoobank.org/urn:lsid:zoobank.org:pub:E5B44B8C-DFD2-423A-A554-62A2D4FB464F       http://zoobank.org/urn:lsid:zoobank.org:act:D3FADC01-5267-4DE4-AB15-A98C01F1B876.

Ixodes (Afrixodes) hyracis n. sp. (Acari: Ixodidae) is described based on females ex the rock hyrax, Procavia capensis (Pallas) (Hyracoidea: Procaviidae) from South Africa. Females of this new species are similar to those of some other Afrotropical species of the subgenus Afrixodes Morel, 1966 such as I. arebiensis Arthur, 1956, I. euplecti Arthur, 1958, I. lunatus Neumann, 1907 and I. rotundatus Arthur, 1958, from which they can be distinguished by the shape of the apron, length of the anterior projection of the basis capituli, length of the auriculae, and length and shape of spurs on palpal segment I, coxae and trochanters.

The identity of Ixodes (Afrixodes) ugandanus Neumann, 1906 (Acari: Ixodidae) is established and its male and female are redescribed based on specimens collected on rodents (Rodentia: Muridae, Thryonomyidae) in Ethiopia and Uganda. Lectotype of I. ugandanus is designated here. Ixodes (Afrixodes) ampullaceus Warburton, 1933 is reestablished as a valid species and its female is redescribed based on specimens collected on rodents (Rodentia: Thryonomyidae), carnivorans (Carnivora: Viverridae) and a bird (Galliformes: Numididae) in Kenya, Malawi, Mozambique, South Africa, Tanzania, and Zimbabwe. Ixodes mossambicensis Santos Dias, 1952 is synonymized with I. ampullaceus. Male and female of Ixodes (Afrixodes) aulacodi Arthur, 1956 are redescribed in greater detail based on specimens collected on rodents (Rodentia: Thryonomyidae) in Benin, Cameroon, and Ivory Coast. All available literature data on these taxa are critically analyzed and discussed. We sequenced the mitochondrial genome of I. aulacodi, compared it to other Ixodes Latreille, 1795 species, and according to our phylogeny from 10 protein-coding mitochondrial genes of 33 Ixodes species, I. aulacodi forms a clade with the only other Afrixodes Morel, 1966 having a sequenced complete mitochondrial genome, Ixodes rubicundus Neumann, 1904.

Cardimyxobolus iriomotensis n. sp. (Cnidaria: Myxosporea: Ortholineidae) is described from the gill filaments of Rhinogobius brunneus (type-host) and R. aonumai aonumai (Gobiiformes: Gobiidae) collected from two rivers on Iriomote-jima Island, located in southern Ryukyus, Okinawa Prefecture, Japan. This new species represents the second record of the genus Cardimyxobolus in Japan and the fourth species of the genus globally. The plasmodium of the new species is spherical, and its spores are ovate, appearing wider than long in valvular view. The shell valves are smooth, and the pair of pyriform polar capsules are subequal in length, occupying the anterior half of the spore body and containing 3-5 coils of the polar tubule. The foramina of each polar capsule are positioned laterally at approximately one-third of the distance from the anterior end of the spore. Cardimyxobolus iriomotensis n. sp. can be distinguished from its congeners by the following key features: 1) a smooth shell valve, in contrast to the 1-6 V-shaped folds found in C. leshanensis; 2) significantly thinner spores (4.4-6.1 μm) compared to C. rhodeus (9.0-10.0 μm); 3) pyriform polar capsules, differing from the spherical capsules in C. leshanensis and C. rhodeus; and 4) narrower spore width (7.5-10.0 μm) and smaller polar capsules (2.6-4.0 μm × 1.4-2.7 μm) than those of C. japonensis (11.3-12.5 μm and 4.2-5.0 μm × 2.9-3.8 μm, respectively). Molecular analysis of 18S rDNA revealed the affinity of the new species for C. japonensis and Triangula percae (Ortholineidae). Cardimyxobolus iriomotensis n. sp. appears to be endemic to the southern Ryukyu region, particularly Iriomote-jima Island, with a geographically restricted distribution, at least in Japan. In addition, this study includes taxonomic notes on the genus Triangula.

A new kathlaniid nematode, Falcaustra peruensis n. sp., was described using light and scanning electron microscopy, based on specimens collected from the intestine of the Titicaca water frog, Telmatobius culeus (Garman) (Anura: Telmatobiidae) in Peru. Falcaustra peruensis n. sp. belongs to the Falcaustra group that is characterized by the presence of a pseudosucker. The new species can be easily differentiated from other congeneric species, with the exception of four species, by its papillae pattern. This pattern includes 6 precloacal papillae, 4 adcloacal papillae, 12 postcloacal papillae, plus 1 median papilla. The new species shares similarities with Falcaustra peruensis n. sp. by having the same papillae pattern (6-4-12 + 1) and a pseudosucker, but can be differentiated from F. sanjuanensis by the morphology of the gubernaculum (triangular with a pair of proximal and distal processes in the new species vs triangular without processes in F. sanjuanensis), the proportion of gubernaculum length relative to total body length (1.2-1.24% in the new species vs 1.56-1.71% in F. sanjuanensis), the morphology of the deirids (button-shaped surrounded by a horseshoe-shaped border in the new species vs elongated surrounded by a circular border in F. sanjuanensis) and body size (males 6.14-7.62 mm and females 4.1-6.8 mm in the new species vs males 11.2-13.5 mm and females 10.1-15.5 mm in F. sanjuanensis). Falcaustra peruensis n. sp. represents the fourth nominal species of the genus in Peru and the fourteenth species described in the Neotropical region.

Ixodes (Ixodes) zacateco n. sp. (Acari: Ixodidae) is described based on females ex the Mexican spiny pocket mouse, Heteromys irroratus Gray (Rodentia: Heteromyidae) from Mexico. Females of this new species are different from all other species of the subgenus Ixodes Latreille, 1795 from the Americas by the development of lateral carinae and punctations on scutum, length of alloscutal setae, shape and size of auriculae, development and size of spurs on coxae and lack of syncoxae.

The integration of molecular data with morphological analysis has greatly advanced the understanding of parasitic diversity, particularly within groups like Dactylogyridae. While morphological features have long been used to classify genera and species, molecular studies have often revealed discrepancies that challenge traditional taxonomies. Urocleidoides (Mizelle & Price, 1964) is one such example, with previous research suggesting it may not be monophyletic. Meanwhile, Annulotrematoides (Kritsky & Boeger, 1995) has lacked any molecular data until now, limiting our understanding of its evolutionary relationships. In this study, we provide the first molecular sequences for Annulotrematoides, which were grouped with Urocleidoides spp. Our analysis of Annulotrematoides bonaerensis Rossin & Timi, 2016 and Urocleidoides surianoae Rossin & Timi, 2016 found parasitizing the gills of Cyphocharax modestus (Fernández-Yépez) revealed a strong phylogenetic relationship between these two species, despite their classification in different genera. This discovery challenges the current morphological-based taxonomy of Urocleidoides and suggests that U. surianoae may not be accurately placed within its genus. The clustering of Urocleidoides with Annulotrematoides for the first time highlights the need for a taxonomic re-evaluation of these groups. Additionally, this work underscores the importance of molecular data in resolving evolutionary relationships and advancing our understanding of parasitic diversity.

Subulura (Murisubulura) andersoni (Cobbold, 1876) is one of 20 species of the genus Subulura known from mammals and one of four species known from murid rodents across South Africa, India, southeast Asia, Japan, New Guinea and Australia. On re-evaluation of all the relevant literature and examination of specimens of S. (M.) andersoni and S. (M.) ortleppi Inglis, 1960, the following taxonomic decisions were made. Subulura (M.) ortleppi, S. (M.) sipirocki Purwanginsih, 2003 and S. (M.) suzukii Yagi & Kamiya, 1981 were placed as synonyms of S. (M.) andersoni based on morphological and morphometric evidence. Subulura hindi Mirza, 1936 was confirmed as a valid species and Latibuccana funambulenis Patwardhan, 1935 declared a species inquirendum. The type locality of S. (M.) andersoni was confirmed as northern India not Sri Lanka (Ceylon). Prevalence and locality data suggested that the focus of infection of S. (M.) andersoni was in the murine Bunomys chrysocomus (Hoffman) from Sulawesi, Indonesia with the geographic range extending to South Africa in the west and Australia in the east.

Phytodietus (Weisia) clavotibialis Shimizu & Konishi, 2018 (Hymenoptera: Ichneumonidae: Tryphoninae: Phytodietini) is a rare and poorly known Darwin wasp, previously known only from the female holotype collected in Japan. In this study, the male is described for the first time based on two specimens. One of these was reared from a tortricid leaf-roller moth feeding on Rhododendron reticulatum D. Don ex G. Don, marking the first host record for both the species and the subgenus Weisia Schmiedeknecht from Tortricidae. New distribution records from India and Taiwan extend the known range of P. (W.) clavotibialis and reveal a biogeographic pattern resembling that of its closest relative, P. (W.) pitambari Kaur & Jonathan, 1979. Partial sequences of mitochondrial CO1 and nuclear 28S rDNA genes were newly obtained, representing the first molecular data for Weisia, and were used in a preliminary phylogenetic analysis. Although the subgenus Euctenopus Ashmead was not included in our analysis, the molecular phylogeny recovered Weisia as the most basal lineage within the genus Phytodietus Gravenhorst, supporting its recognition as a distinct subgenus, while the monophyly of the subgenera Phytodietus and Neuchorus Uchida was not supported. Given the longstanding confusion and our results, it is concluded that these subgenera are best treated as a single subgenus; thus, Neuchorus syn. nov., together with its previously recognized synonym Doratistes Seyrig, is synonymized under Phytodietus. Additionally, P. (W.) clavotibialis appears to be associated with secondary natural environments characteristic of Satoyama landscapes, raising conservation concerns due to ongoing habitat degradation.

Adults of Corynosoma evae Zdzitowiecki, 1984 were described from the leopard seal Hydrurga leptonyx (Blainville) in South Shetlands, South Georgia, and Falkland Islands and juveniles from the Antarctic dragonfish Parachaenichthys georgianus (Fischer) were also reported. We describe excysted juveniles of a morphologically indistinguishable cryptic species, Corynosoma paraevae n. sp. from the body cavity of Notothenia coriiceps Richardson collected off Galindez Island, Argentine Islands, West Antarctica. Our juveniles were generally smaller than those of adults of C. evae but most other measurements were comparable. We compared our morphometric description of C. paraevae n. sp. juveniles from N. coriiceps with the one available for C. evae adults collected from H. leptonyx and the juveniles redescribed from three other species of Antarctic notothenioid fish. We have included optical microscopy and scanning electron microscope (SEM) images of internal and external structures, respectively. Various cuts of proboscis hooks and roots studied by Energy Dispersive X-ray analysis (EDXA) revealed the highest levels of calcium, phosphorous, and sulfur reaching 50.55%, 20.30%, and 4.15%, respectively. This pattern is compared with those of cystacanths of 6 other species of acanthocephalans. Our molecular description of the new cryptic species involved the 18S subunit of ribosomal DNA and mitochondrial cytochrome c oxidase subunit 1 (cox1) from mitochondrial DNA. The cox1 tree showed that the four isolates of the new species and two of C. evae from the same collection form separate clades that confirmed C. paraevae n. sp. as different species. The cox1 interspecific relationship inferred with 14 sequences revealed 08 groupings alienated from each other.

Adult flukes of the genus Orchidasma were collected from the intestinal tracts of loggerhead Caretta caretta and Kemp's ridley Lepidochelys kempii sea turtles as part of diagnostic investigations into sea turtle strandings. Two morphologically distinct species were present: one represented the type-species Orchidasma amphiorchis and an undescribed species. Orchidasma amphiorchis is redescribed and Orchidasma orchilobata n. sp. is described based on morphological, molecular and phylogenetic analyses. Oxford Nanopore Technology and Illumina sequencing were used to generate complete mitochondrial genomes and nuclear ribosomal operons for both species. Sanger sequencing from additional hologenophore specimens for both species were used to assess interspecific and intraspecific variability. Single locus phylogenetic analyses of aligned partial 28S rRNA gene sequences and concatenation of mitochondrial genes of the two species and other trematodes were performed to assess the taxonomic affinity of Orchidasma. Analysis of partial 28S rRNA gene sequences placed O. amphiorchis and O. orchilobata n. sp. as members of the Monorchioidea and closest to Skrjabinopsolus nudidorsalis, a member of Deropristidae. This disagreed with previous inclusion of Orchidasma as a member of Telorchiidae within Plagiorchioidea. Whole mitochondrial genome sequencing and phylogenetic analysis resulted in similar topology, suggesting a revision to include Orchidasma as a member of Deropristidae supported by shared morphological characters and nucleotide sequence data with deropristid congeners.