Phylogenetic relationships of the Dactylogyridae Bychowsky, 1933 (Monogenea: Dactylogyridea): the need for the systematic revision of the Ancyrocephalinae Bychowsky, 1937

Phylogenetic analyses based on partial 18S rDNA sequences of polyonchoinean monogeneans were conducted in order to investigate the relationships between selected families and subfamilies of the Dactylogyrinea, mainly within the Dactylogyridae. We tested the status of the Ancyrocephalidae sensu Bychowsky & Nagibina (1978) and the Ancyrocephalinae sensu Kritsky & Boeger (1989). Within the Dactylogyrinea, the Diplectanidae and Dactylogyridae are well supported by maximum likelihood and maximum parsimony analyses, but their phylogenetic relationship with the Pseudomurraytrematidae remains unresolved. Phylogenetic relationships between the Pseudodactylogyrinae, Ancyrocephalinae, Ancylodiscoidinae and Dactylogyrinae indicate paraphyly of the Ancyrocephalidae sensu Bychowsky & Nagibina (1978). The group of species recently considered as the Dactylogyridae sensu Kritsky & Boeger (1989) comprises two sister groups. The first group includes the freshwater Ancyrocephalinae and the Ancylodiscoidinae. The second group includes the Pseudodactylogyrinae, Dactylogyrinae and the Ancyrocephalinae from the fish species Siganus doliatus and Tetraodon fluviatilis. The non-monophyly of the Ancyrocephalinae (i.e. the non-monophyly of the group of species recently considered as members of Ancyrocephalinae), previously suggested by Kritsky & Boeger (1989) using the morphological characters, indicates that classification of the Dactylogyridae needs to be revised.     

Dactylogyrids (Monogenoidea: Polyonchoinea) parasitising the gills of snappers (Perciformes: Lutjanidae): Species of Euryhaliotrema Kritsky & Boeger, 2002 from the golden snapper Lutjanus johnii (Bloch) off northern Australia, with a redescription of Euryhaliotrema johni (Tripathi, 1959) and descriptions of two new species

Three species of Euryhaliotrema Kritsky & Boeger, 2002 (Monogenoidea: Dactylogyridae) were collected from the gills of four golden snapper Lutjanus johnii (Bloch) (Lutjanidae) from the marine and brackish waters off Darwin, Northern Territory, Australia. Type-specimens of Ancyrocephalus johni Tripathi, 1959 apparently have not survived and the possibility existed that the species was based on specimens representing more than one species. Euryhaliotrema johni (Tripathi, 1959) (sensu Young, 1968) was redescribed and determined to most likely represent A. johni, originally described from the River Hooghly, Diamond Harbour, India. Two new species were described. Euryhaliotrema longibaculoides n. sp. was most similar to Euryhaliotrema longibaculum (Zhukov, 1976) Kritsky & Boeger, 2002 from Lutjanus spp. from the western Atlantic Ocean. It differed from E. longibaculum by having a male copulatory organ (MCO) with an elongate comparatively delicate shaft and a bulbous base (MCO U- or J-shaped with funnel-shaped base in E. longibaculum). Based on the comparative morphology of the haptoral sclerites, Euryhaliotrema lisae n. sp. was most similar to Euryhaliotrema cryptophallus Kritsky & Yang, 2012 from the gills of the mangrove red snapper Lutjanus argentimaculatus (Forsskål) from the South China Sea. Euryhaliotrema lisae differed from E. cryptophallus by having a copulatory complex with an obvious weakly sclerotised J-shaped MCO (MCO cryptic, delicate, and with a shaft comprising about one counterclockwise ring in E. cryptophallus).     

Monogeneans of the catfish Pimelodus blochii Valenciennes (Siluriformes: Pimelodidae) from the Brazilian Amazon,with a description of a new species of Ameloblastella Kritsky,Mendoza-Franco & Scholz, 2000 (Monogenea: Dactylogyridae)

Ameloblastella amazonica n. sp. (Monogenea: Dactylogyridae) collected on the gills of Pimelodus blochii Valenciennes (Siluriformes: Pimelodidae) from Rivers Acre and Iaco, State of Acre (Brazil) is described. The new species differs from the congeners mainly by the morphology of the dorsal bar, i.e. slightly U-shaped bearing a posteriorly directed flap, arising from the anterior edge of its middle third. The most morphologically similar congeners, A. paranaensis (França, Isaac, Pavanelli & Takemoto, 2003) and A. satoi Monteiro, Kritsky & Brasil-Sato, 2010, resemble A. amazonica n. sp. regarding the general structure of the copulatory complex; however, besides other features, they also differ from the new species because their hooks are similar in size (vs hooks with three different sizes). In addition to the dorsal bar lacking a flap, A. amazonica n. sp. can be differentiated from all congeners based on the combination of the following features: size of hooks (one or two different sizes), shape of the dorsal bar (other than slightly U-shaped), anchor points largely passing the level of superficial root (vs not or slightly passing it), number of MCO rings (other than 3–4) and structure of the articulation between the MCO base and the accessory piece (other than thick, medium-sized, smooth and tubular). Demidospermus leptosynophallus Kritsky & Gutierrez, 1998 and Scleroductus yuncensi Jara & Cone, 1989 were also found infesting P. blochii, both representing new host and locality records.

     

Monogenea of marine fishes from Hainan Island, China. VIII. Two new species of Euryhaliotrema Kritsky & Boeger, 2002 (Dactylogyridae) from Lutjanus argentimaculatus (Teleostei: Lutjanidae)

This paper reports two new species of Euryhaliotrema Kritsky & Boeger, 2002 collected from the gills of Lutjanus argentimaculatus (Forsskål). E. xinyingense n. sp. is similar to Euryhaliotrema atlanticum Kritsky & Boeger, 2002 in the structure of copulatory apparatus, but differs from the latter in the shape of anchors and the structure of vagina. E. hainanense n. sp. also closely resembles E. atlanticum Kritsky & Boeger, 2002, but differs from the latter in the structure of haptor and the shape of accessory piece.     

Verrucophora farcimen gen. et sp. nov. (Dictyochophyceae,Heterokonta)—a bloom‐forming ichthyotoxic flagellate from the Skagerrak,Norway1

Since 1998, a heterokont flagellate initially named Chattonella aff. verruculosa has formed recurrent extensive blooms in the North Sea and the Skagerrak, causing fish mortalities. Cells were isolated from the 2001 bloom off the south coast of Norway, and monoalgal cultures were established and compared with the Chattonella verruculosa Y. Hara et Chihara reference strain NIES 670 from Japan. The cells in Norwegian cultured isolates were very variable in size and form, being large oblong (up to 34 μm long) to small rounded (5–9 μm in diameter) with two unequal flagella, numerous chloroplasts, and mucocysts. The SSU and partial LSU rDNA sequences of strains from Norway and Japan were compared and differed by 0.4% (SSU) and 1.3% (LSU), respectively. Five strains from Norway were identical in the LSU rDNA region. Phylogenetic analyses based on heterokont SSU and concatenated SSU + LSU rDNA sequences placed C. aff. verruculosa and the Japanese C. verruculosa within the clade of Dictyochophyceae, with the picoflagellate Florenciella parvula Eikrem as the closest relative. Ultrastructure, morphology, and pigment composition supported this affinity. We propose the name Verrucophora farcimen sp. et gen. nov. for this flagellate and systematically place it within the class Dictyochophyceae. Our studies also show that C. verruculosa from Japan is genetically and morphologically different but closely related to V. farcimen. The species is transferred from the class Raphidophyceae to the class Dictyochophyceae and renamed Verrucophora verruculosa. We propose a new order, Florenciellales, to accommodate V. farcimen, V. verruculosa, and F. parvula.     

Calicotyle hydrolagi n. sp. (Monogenea: Monocotylidae) infecting the deep-sea Eastern Pacific black ghost shark Hydrolagus melanophasma from the Atacama Trench,with comments on host specificity of Calicotyle spp.

We describe Calicotyle hydrolagi n. sp. (Monogenea: Monocotylidae) infecting the cloaca of deep-water Eastern Pacific black ghost sharks, Hydrolagus melanophasma captured as bycatch at a local fishery for Patagonian toothfish Dissostichus eleginoides, (Nototheniidae) in the Atacama Trench using morphological and nucleotide (LSU rRNA and SSU rRNA) data. This new species is differentiated from its congeners by a number of characters, including the absence of a cecal diverticula, the size and shape of the male copulatory organ and the shape of the vagina, as well as by differences in molecular data (SSU rRNA and LSU rRNA). The suitability of some sclerotized structures such as the male copulatory organ (MCO) as a taxonomic character is discussed; specifically, we found that the relationship between MCO and total length exhibit different trends in members of Calicotyle isolated from sharks, skates and chimaeras. Additional efforts to obtain sample of Calicotyle species and further molecular studies based on ribosomal and mitochondrial genes are necessary to clarify the degree of host specificity in this genus. Additionally, this is the first report of a member of Calicotyle to be reported in the Southeastern Pacific Ocean.     

Gambierdiscus (Gonyaulacales,Dinophyceae) diversity in Vietnamese waters with description of G. vietnamensis sp. nov.

Viet Nam has a coastline of 3200 km with thousands of islands providing diverse habitats for benthic harmful algal species including species of Gambierdiscus. Some of these species produce ciguatera toxins, which may accumulate in large carnivore fish potentially posing major threats to public health. This study reports five species of Gambierdiscus from Vietnamese waters, notably G. australes, G. caribaeus, G. carpenteri, G. pacificus, and G. vietnamensis sp. nov. All species are identified morphologically by LM and SEM, and identifications are supported by molecular analyses of nuclear rDNA (D1–D3 and D8–D10 domains of LSU, SSU, and ITS1-5.8S-ITS2 region) based on cultured material collected during 2010–2021. Statistical analyses of morphometric measurements may be used to differentiate some species if a sufficiently large number of cells are examined. Gambierdiscus vietnamensis sp. nov. is morphologically similar to other strongly reticulated species, such as G. belizeanus and possibly G. pacificus; the latter species is morphologically indistinguishable from G. vietnamensis sp. nov., but they are genetically distinct, and molecular analysis is deemed necessary for proper identification of the new species. This study also revealed that strains denoted G. pacificus from Hainan Island (China) should be included in G. vietnamensis sp. nov.     

Intra-specific variation of Kudoa spp. (Myxosporea: Multivalvulida) from apogonid fishes (Perciformes), including the description of two new species, K. cheilodipteri n. sp. and K. cookii n. sp., from Australian waters

Kudoa spp. from the musculature and intestinal mucosa of species of the teleost family Apogonidae were examined for their taxonomic identity. Two novel species are characterised: Kudoa cheilodipteri n. sp. from the musculature of Cheilodipterus quinquelineatus Cuvier, Ostorhinchus cyanosoma (Bleeker) and O. aureus (Lacépède); and Kudoa cookii n. sp. from the submucosa of the intestines of O. cookii (Macleay) only. Both species are characterised using morphology, small subunit ribosomal DNA (SSU rDNA), large subunit ribosomal DNA (LSU rDNA), and biological characters. Three new host records, O. cyanosoma, O. aureus and Apogon doederleini, and associated geographical, morphological and genetic data are also provided for Kudoa whippsi Burger & Adlard, 2010. Morphological and molecular intra-specific variation of all isolates assigned to K. whippsi is also examined. Phylogenetic analyses further support the idea that tissue tropism is a distinguishing character between morphologically similar species; species reported here display close relatedness to morphologically similar species infecting the same tissue within their hosts.     

Eight new species ofHamatopeduncularia Yamaguti, 1953 (Monogenea: Ancyrocephalidae) from Ariidae of Peninsular Malaysia

Eleven species of Hamatopeduncularia Yamaguti, 1953 were found on six species of ariids caught off the west coast of Peninsular Malaysia. They are: H. arii Yamaguti, 1953 from Arius maculatus; H. thalassini Bychowsky & Nagibina, 1969 from A. thalassinus; H. simplex Bychowsky & Nagibina, 1969 from Osteogeneiosus militaris; H. isosimplex n. sp. from A. venosus, A. maculatus and A. sagor; H. malayanus n. sp. from A. caelatus; H. manjungi n. sp. from A. thalassinus; H. papernai n. sp. from A. maculatus; H. elongatum n. sp. from A. thalassinus; H. longicopulatrix n. sp. from A. venosus; H. venosus n. sp. from A. venosus; and H. malaccensis n. sp. from O. militaris and A. maculatus.     

Cryptic Speciation in the Genus Cryptoglena (Euglenaceae) Revealed by Nuclear and Plastid SSU and LSU rRNA Gene

The photosynthetic euglenoid genus Cryptoglena is differentiated from other euglenoid genera by having a longitudinal sulcus, one chloroplast, two large trough‐shaped paramylon plates positioned between the chloroplast and pellicle, and lack of metaboly. The genus contains only two species. To understand genetic diversity and taxonomy of Cryptoglena species, we analyzed molecular and morphological data from 25 strains. A combined data set of nuclear SSU and LSU and plastid SSU and LSU rRNA genes was analyzed using Bayesian, maximum likelihood, maximum parsimony, and distance (neighbor joining) methods. Although morphological data of all strains showed no significant species‐specific pattern, molecular data segregated the taxa into five clades, two of which represented previously known species: C. skujae and C. pigra, and three of which were designated as the new species, C. soropigra, C. similis, and C. longisulca. Each species had unique molecular signatures that could be found in the plastid SSU rRNA Helix P23_1 and LSU rRNA H2 domain. The genetic similarity of intraspecies based on nr SSU rDNA ranged from 97.8% to 100% and interspecies ranged from 95.3% to 98.9%. Therefore, we propose three new species based on specific molecular signatures and gene divergence of the nr SSU rDNA sequences.     

Phylogenetic Reappraisal of the Genus Monomorphina (Euglenophyceae) Based on Molecular and Morphological Data

A morphological and molecular examination of the genus Monomorphina was conducted on 46 strains isolated mainly from Korea. The strains were divided into two types based on morphological data: Monomorphina aenigmatica and M. pyrum ‐ like species. Phylogenetic analysis based on a combined data set of nuclear SSU and LSU and plastid SSU and LSU rDNA showed that the strains could be divided into eight clades: Clade A of M. aenigmatica, Clade B of the isolates (M. pyropsis) from Michigan, USA, Clade C of M. pseudopyrum, Clade D of the isolates (M. pyroria) from Bremen, Germany, Clade E of M. soropyrum, Clade F of M. pyriformis, Clade G of M. parapyrum, and Clade H of M. pyrum. Six of these clades came from strains that would be considered M. pyrum sensu Kosmala et Zakry?, one of which could be recognized as a traditional species (M. pyrum) and five were designated as new species; each species had unique molecular signatures at nr SSU rDNA helix 17 and 17′ and spacer E23_14′‐E23_15. The species of Monomorphina had a wide range of genetic diversity with interspecies sequence similarity of 85.6%–97.1% and intraspecies similarity of 96.4%–99.9%. Our results suggested that genetic diversity found in the M. pyrum complex justifies the recognition of a minimum of eight species within this genus, based on specific molecular signatures and gene divergence of the nr SSU rDNA sequences.     

<Emphasis Type="Italic">Nataliella marcelli</Emphasis> n. g., n. sp. (Cestoda: Trypanorhyncha: Rhinoptericolidae) from Hawaiian fishes

A new trypanorhynch cestode from Hawaiian waters is described based on specimens in the collection of the Meguro Parasitological Museum, Tokyo, and newly collected specimens. Nataliella marcelli n. g., n. sp. is characterised by its elongate, craspedote scolex with four small, ear-shaped bothria, an elongate pars vaginalis and long bulbs. The homeoacanthous homeomorphous metabasal armature is comprised of five or six slender, solid hooks per half spiral row. A distinctive basal armature is present, including a combination of six characteristically shaped macrohooks not previously described for trypanorhynchs. The surface ultrastructure consists of gladiate spiniform microtriches that cover the distal and proximal bothrial surface and filiform microtriches on the scolex peduncle. The adults are not known. Nataliella is assigned to the family Rhinoptericolidae Carvajal & Campbell, 1975 based on its possession of four bothria, prebulbar organs and no chainette or intercalary hooks. The family diagnosis is amended to accommodate the new genus. Rhinoptericola megacantha Carvajal & Campbell, 1975 is considered the most closely related species, a position that has been confirmed by molecular analyses of the SSU and LSU rDNA. Nataliella n. g. is intermediate in morphology between the homeoacanth family Tentaculariidae Poche, 1926 (superfamily Tentacularioidea) and the Rhinoptericolidae and other eutetrarhynchid genera (superfamily Eutetrarhynchoidea), sharing characters of both superfamilies.     

A further phylogenetic study of the heterotrophic dinoflagellate genus, Protoperidinium (Dinophyceae) based on small and large subunit ribosomal RNA gene sequences

The heterotrophic marine dinoflagellate genus Protoperidinium is the largest genus in the Dinophyceae. Previously, we reported on the intrageneric and intergeneric phylogenetic relationships of 10 species of Protoperidinium, from four sections, based on small subunit (SSU) rDNA sequences. The present paper reports on the impact of data from an additional 5 species and, therefore, an additional two sections, using the SSU rDNA data, but now also incorporating sequence data from the large subunit (LSU) rDNA. These sequences, in isolation and in combination, were used to reconstruct the evolutionary history of the genus. The LSU rDNA trees support a monophyletic genus, but the phylogenetic position within the Dinophyceae remains ambiguous. The SSU, LSU and SSU + LSU rDNA phylogenies support monophyly in the sections Avellana, Divergentia, Oceanica and Protoperidinium, but the section Conica is paraphyletic. Therefore, the concept of discrete taxonomic sections based on the shape of 1′ plate and 2a plate is upheld by molecular phylogeny. Furthermore, the section Oceanica is indicated as having an early divergence from other groups within the genus. The sections Avellana and Excentrica and a clade combining the sections Divergentia/Protoperidinium derived from Conica‐type dinoflagellates independently. Analysis of the LSU rDNA data resulted in the same phylogeny as that obtained using SSU rDNA data and, with increased taxon sampling, including members of new sections, a clearer idea of the evolution of morphological features within the genus Protoperidinium was obtained. Intraspecific variation was found in Protoperidinium conicum (Gran) Balech, Protoperidinium excentricum (Paulsen) Balech and Protoperidinium pellucidum Bergh based on SSU rDNA data and also in Protoperidinium claudicans (Paulsen) Balech, P. conicum and Protoperidinium denticulatum (Gran et Braarud) Balech based on LSU rDNA sequences. The common occurrence of base pair substitutions in P. conicum is indicative of the presence of cryptic species.     

Halosarpheia japonica sp. nov. (Halosphaeriales, Ascomycota) from marine habitats in Japan

A new Halosarpheia species, collected from driftwood from Hakkeijima beach, Yokohama, Japan, is described and illustrated and is compared with other species of the genus. The new fungus was growing together with its anamorph on a piece of decaying wood. SSU and LSU rDNA sequences for both morphs were 99% similar. Phylogenetic analyses of SSU and LSU rDNA sequences of the both morphs confirm their anamorph–teleomorph relationship and placed the new fungus in the Halosarpheia sensu stricto clade with high statistical support. Halosarpheia japonica is characterized by its polar appendage that is initially enclosed in a cellular sheath and dissolves in water, the appendage then swells to form a huge tree-like structure. The other three species currently included in Halosarpheia sensu stricto differ from H. japonica by having two polar appendages that uncoil in water to form long filaments.     

New taxa refresh the phylogeny and classification of pleurostomatid ciliates (Ciliophora,Litostomatea)

A high diversity of pleurostomatid ciliates has been discovered in the last decade, and their systematics needs to be improved in the light of new findings concerning their morphology and molecular phylogeny. In this work, a new genus, Protolitonotus gen. n., and two new species, Protolitonotus magnus sp. n. and Protolitonotus longus sp. n., were studied. Furthermore, 19 novel nucleotide sequences of SSU rDNA, LSU rDNA and ITS1‐5.8S‐ITS2 were collected to determine the phylogenetic relationships and systematic positions of the pleurostomatid ciliates in this study. Based on both molecular and morphological data, the results demonstrated that: (i) as disclosed by the sequence analysis of SSU rDNA, LSU rDNA and ITS1‐5.8S‐ITS2, Protolitonotus gen. n. is sister to all other pleurostomatids and thus represents an independent lineage and a separate family, Protolitonotidae fam. n., which is defined by the presence of a semi‐suture formed by the right somatic kineties near the dorsal margin of the body; (ii) the families Litonotidae and Kentrophyllidae are both monophyletic based on both SSU rDNA and LSU rDNA sequences, whereas Amphileptidae are non‐monophyletic in trees inferred from SSU rDNA sequences; and (iii) the genera Loxophyllum and Kentrophyllum are both monophyletic, whereas Litonotus is non‐monophyletic based on SSU rDNA analyses. ITS1‐5.8S‐ITS2 sequence data were used for the phylogenetic analyses of pleurostomatids for the first time; however, species relationships were less well resolved than in the SSU rDNA and LSU rDNA trees. In addition, a major revision to the classification of the order Pleurostomatida is suggested and a key to its families and genera is provided.     

MORPHOLOGY AND MOLECULAR ANALYSES OF THREE TOXIC SPECIES OF GAMBIERDISCUS (DINOPHYCEAE): G. PACIFICUS, SP. NOV., G. AUSTRALES, SP. NOV., AND G. POLYNESIENSIS, SP. NOV.

Three new dinoflagellate species, Gambierdiscus polynesiensis, sp. nov., Gambierdiscus australes, sp. nov., and Gambierdiscus pacificus, sp. nov., are described from scanning electron micrographs. The morphology of the three new Gambierdiscus species is compared with the type species Gambierdiscus toxicus Adachi et Fukuyo 1979, and two other species: Gambierdiscus belizeanus Faust 1995 and Gambierdiscus yasumotoi Holmes 1998. The plate formula is: Po, 3′, 7", 6C, 8S, 5‴, 1p, 2". Culture extracts of these three new species displayed both ciguatoxin- and maitotoxin-like toxicities. The following morphological characteristics differentiated each species. 1) Cells of G. polynesiensis are 68–85 μm long and 64–75 μm wide, and the cell’s surface is smooth. They are identified by a large triangular apical pore plate (Po), a narrow fish-hook opening surrounded by 38 round pores, and a large, broad posterior intercalary plate (1p) wedged between narrow postcingular plates 2‴ and 4‴. Plate 1p occupies 60% of the width of the hypotheca. 2) Cells of G. australes also have a smooth surface and are 76–93 μm long and 65–85 μm wide in dorsoventral depth. They are identified by the broad ellipsoid apical pore plate (Po) surrounded by 31 round pores and a long and narrow 1p plate wedged between postcingular plates 2‴ and 4‴. Plate 1p occupies 30% of the width of the hypotheca. 3) Cells of G. pacificus are 67–77 μm long and 60–76 μm wide in dorsoventral depth, and its surface is smooth. They are identified by the four-sided apical pore plate (Po) surrounded by 30 round pores. A short narrow 1p plate is wedged between the wide postcingular plates 2‴ and 4‴. Plate 1p occupies 20% of the width of the hypotheca. These three newly described species were also characterized by isozyme electrophoresis and DNA sequencing of the D8–D10 region of their large subunit (LSU) rRNA genes. The consistency between species designations based on SEM microscopy and classification inferred from biochemical and genetic heterogeneities was examined among seven isolates of Gambierdiscus. Their classification into four morphospecies was not consistent with groupings inferred from isozyme patterns. Three molecular types could be distinguished based on the comparison of their LSU rDNA sequences. Although G. toxicus TUR was found to be more closely related to G. pacificus, sp. nov. than to other G. toxicus strains, the molecular classification was able to discriminate G. polynesiensis, sp. nov. and G. australes, sp. nov. from G. toxicus. These results suggest the usefulness of the D8–D10 portion of the Gambierdiscus LSU rDNA as a valuable taxonomic marker.     

Morphology,ultrastructure and molecular phylogeny of cyst-producing Caladoa arcachonensis gen. et sp. nov. (Peridiniales,Dinophyceae) from France and Indonesia

The dinoflagellate order Peridiniales encompasses several well circumscribed families. However, the family level of some genera, such as Bysmatrum and Vulcanodinium, has remained elusive for many years. Four Peridinium-like strains were established from the Atlantic coast of France and North Sulawesi, Indonesia through cyst germination or isolation of single cells. The cyst-theca relationship was established on specimens from the French Atlantic. Their morphologies were examined using light, scanning and transmission electron microscopy. The cells were characterized by a much larger epitheca relative to the hypotheca, a large anterior sulcal (Sa) plate deeply intruding the epitheca and a small first anterior intercalary plate. The plate formula was identified as Po, cp, X, 4′, 3a, 7′′, 6C, 5S, 5′′′, 2′′′′, shared by Apocalathium, Chimonodinium, Fusiperidinium and Scrippsiella of the family Thoracosphaeraceae but the configuration of Sa plate and anterior intercalary plates is different. Transmission electron microscopy showed that the eyespot was located within a chloroplast comprising two rows of lipid globules and thus belongs to type A. All four strains were classified within a new genus Caladoa as C. arcachonensis gen. et sp. nov. Small subunit ribosomal DNA (SSU rDNA), partial large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer ribosomal DNA (ITS rDNA) sequences were obtained from all strains. Genetic distance based on ITS rDNA sequences between French and Indonesian strains reached 0.17, suggesting cryptic speciation in C. arcachonensis. The maximum likelihood and Bayesian inference analysis based on concatenated data from SSU and LSU rDNA sequences revealed that Caladoa is monophyletic and closest to Bysmatrum. Our results supported that Caladoa and Bysmatrum are members of the order Peridiniales but their family level remains to be determined. Our results also support that Vulcanodinium is closest to the family Peridiniaceae.     

A redescription of Pseudorhabdosynochus epinepheli (Yamaguti, 1938), the type-species of Pseudorhabdosynochus Yamaguti, 1958 (Monogenea: Diplectanidae), and the description of P. satyui n. sp. from Epinephelus akaara off Japan

Pseudorhabdosynochus epinepheli (Yamaguti, 1938) has been recorded from a variety of hosts, mainly groupers. All type-specimens of Diplectanum epinepheli Yamaguti, 1938, Pseudorhabdosynochus epinepheli Yamaguti, 1958 and Cycloplectanum hongkongensis Beverley-Burton & Suriano, 1981 are figured: it is concluded, as did Kritsky & Beverley-Burton (1986), that the three species are synonymous. In addition, numerous monogenean specimens from a deep-sea grouper, Epinephelus chlorostigma, collected off New Caledonia, South Pacific, were prepared using various methods and described. These specimens are also conspecific with P. epinepheli (Yamaguti, 1938) and represent a new geographical record. This species has a sclerotised vagina with a very characteristic primary chamber. The simultaneous presence of P. lantauensis (Beverley-Burton & Suriano, 1981) and P. epinepheli was noted in both type-slides of D. epinepheli from Japan (host: E. akaara) and C. hongkongensis from Hong Kong (host: E. bruneus). Several causes are suspected for the alleged ‘generalist’ character of P. epinepheli, including the misidentification of either fish or monogeneans and the accidental exchanges of monogeneans between fishes of different species kept alive in the same tank. Finally, the confirmed list of hosts of P. epinepheli includes E. akaara, E. awoara and E. chlorostigma; it is suggested that the latter, a widespread deep-sea fish, serves as a reservoir for the infection of the other species, which are associated with shallow waters. P. satyui n. sp. is described from two specimens found on slides from E. akaara (from the Inland Sea of Japan) deposited by Yamaguti; the new species has a sclerotised vagina with characteristic spherical chambers.

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Résumé   Pseudorhabdosynochus epinepheli (Yamaguti, 1938) a été mentionné chez différents h?tes, surtout des mérous. Tous les spécimens-types de Diplectanum epinepheli Yamaguti, 1938, Pseudorhabdosynochus epinepheli Yamaguti, 1958 et Cycloplectanum hongkongensis Beverley-Burton & Suriano, 1981 sont figurés, et on conclut, comme Kritsky & Beverley-Burton (1986), que les trois espèces sont synonymes. De plus, de nombreux spécimens de monogènes collectés chez un mérou de profondeur, Epinephelus chlorostigma, de Nouvelle-Calédonie, Pacifique Sud, ont été préparés avec des méthodes variées. Ces spécimens sont aussi conspécifiques de P. epinepheli (Yamaguti, 1938) et la Nouvelle-Calédonie représente une nouvelle mention géographique. L’espèce a une vagin sclérifié avec une chambre primaire très caractéristique. La présence simultanée de P. lantauensis (Beverley-Burton & Suriano, 1981) et P. epinepheli a été notée dans les lames-types de D. epinepheli du Japon (h?te, E. akaara) et de C. hongkongensis de Hong-Kong (h?te, E. bruneus). Plusieurs causes sont soup?onnées pour le caractère prétendument ‘généraliste’ de P. epinepheli, dont les mauvaises identifications de poissons, des monogènes, et l’échange accidentel de monogènes chez des poissons gardés vivants ensemble dans un même contenant. Finalement, la liste des h?tes confirmés de P. epinepheli comprend E. akaara, E. awoara et E. chlorostigma. On fait l’hypothèse que E. chlorostigma, espèce de profondeur, a servi de réservoir pour l’infestation des autres espèces, plus associées aux eaux peu profondes. P. satyui n. sp. est décrit de deux spécimens trouvés dans des lames de parasites de E. akaara (de la mer intérieure du Japon) déposées par Yamaguti. La nouvelle espèce a un vagin sclérifié avec des chambres sphériques caractéristiques.

     

Gyrodactylus anarhichatis n. sp. and G. microanchoratus n. sp. (Monogenea: Gyrodactylidae) from the Atlantic wolf-fish Anarhichas lupus (Anarhichadidae) off the coast of Norway

The gyrodactylid monogeneans Gyrodactylus anarhichatis n. sp. and G. microanchoratus n. sp. are reported from the skin and fins of wild Atlantic wolf-fish Anarhichas lupus L. caught off the coast of northern Norway. G. anarhichatis n. sp. is also reported from farmed Atlantic wolf-fish and spotted wolf-fish A. minor Olafsen. G. anarhichatis n. sp. most closely resembles G. corti Mizelle & Kritsky, 1967, but is also similar to G. perlucidus Bychowsky & Poljansky, 1953 and G. errabundus Malmberg, 1970, while G. microanchoratus n. sp. differs from most other Gyrodactylus spp. by having marginal hooks longer than anchors and a peculiar lump on the marginal hook sickle toe pointing towards the sickle point.     

Six new species of Rhamnocercus Monaco,Wood & Mizelle, 1954 (Monogenea: Diplectanidae) infecting the gills from South American sciaenid fishes

A parasitological survey searching diplectanids (Monogenea: Diplecatnidae) infesting the gills of marine fishes from South America was carried out during the 2019–2020 period. The gills of four sciaenid species, 2 Cheilotrema fasciatum Tschudi, 1 smalleye croaker Nebris microps Cuvier, 2 royal highhat Pareques lanfeari (Barton), and 1 minor stardrum Stellifer minor (Tschudi), were sampled. Six new species of Rhamnocercus Monaco, Wood & Mizelle, 1954 were described: Rhamnocercus chacllae n. sp. and Rhamnocercus chaskae n. sp. from P. lanfeari, Rhamnocercus fasciatus n. sp. from C. fasciatum, Rhamnocercus microps n. sp. from N. microps, and Rhamnocercus rimaci n. sp. and Rhamnocercus tantaleani n. sp. from S. minor. Rhamnocercus chacllae n. sp. can be differentiated from its congeners by its L-shaped male copulatory organ (MCO) and by having an anteromedial slight notch at ventral bar. Rhamnocercus chaskae n. sp. differs from the other species of the genus by its long and straight MCO with bifid distal end and by having haptoral accessory spines at level of ventral bar with quadrifid distal portion. Rhamnocercus fasciatus n. sp. is characterized by possessing a straight and long MCO with truncated distal end, haptoral accessory spines at level of ventral bar with bifid distal portion, dorsal bars with a knob at lateral extremity, and a large vagina with bell-shaped. Rhamnocercus microps n. sp. differs from all congeners mainly by having a short and straight MCO with the distal end of internal tube spatulate and uncovered by external tube. Rhamnocercus rimaci n. sp. is can be distinguished from all other species of Rhamnocercus by having an almost J-shaped MCO with the distal end of external tube slight expanded and the distal end of internal tube narrow and uncovered by external tube. Rhamnocercus tantaleani n. sp. is mainly characterized by its MCO, which is tubular and straight, having the distal end of external tube bifurcated (right branch well-expanded and left branch narrow) and the distal end of internal tube enveloped by left branch of the external tube. This is the first data on the parasites of P. lanfeari, a little known, but popular fish in local markets from Peru. Rhamnocercus microps n. sp. is the first described species of Rhamnocercus in Brazil. The present finding brings to 12, the number of known species of Rhamnocercus. A key to Rhamnocercus species is provided.