Pseudorhabdosynochus sulamericanus (Monogenea, Diplectanidae), a parasite of deep-sea groupers (Serranidae) occurs transatlantically on three congeneric hosts (Hyporthodus spp.), one from the Mediterranean Sea and two from the western Atlantic

Morphological and molecular characterisation of Tristoma integrum Diesing, 1850 (Monogenea, Capsalidae), including its complete mitogenome

Capsalids are monopisthocotylean monogenean parasites found on the skin and gills of fish. Capsalines (subfamily Capsalinae) are large-sized capsalids, parasitic on highly prized gamefish, and species of Tristoma parasitise only the gills of swordfish (Xiphias gladius). We obtained specimens of Tristoma integrum Diesing, 1850 from swordfish collected off Algeria in the Mediterranean Sea. Here, we describe the specimens, including the key systematics characters of dorsolateral body sclerites. One specimen was used for a next generation sequencing analysis but a part of it, including the sclerites, was mounted on a permanent slide, drawn, and deposited in a curated collection. We characterised the complete mitogenome, the ribosomal cluster (including 18S and 28S) and additional genes such as Elongation factor 1 alpha (EF1α) and Histone 3. We also retrieved molecular information from the host tissue present in the gut of the monogenean and provide the sequence of the complete rRNA cluster of the host, X. gladius. The mitogenome of T. integrum is 13 968 bp in length and codes for 12 protein, 2 rRNA and 22 tRNA. Phylogenies of capsalids were generated from 28S sequences and concatenated mitochondrial protein-coding genes, respectively. In the 28S phylogeny, most subfamilies based on morphology were not found to be monophyletic, but the Capsalinae were monophyletic. In both phylogenies, the closest member to Tristoma spp. was a member of the Capsaloides. In an Appendix, we report the complex nomenclatural history of Tristoma Cuvier, 1817 and its species.

Three new species of Pseudorhabdosynochus (Monogenea, Diplectanidae) from several species of Cephalopholis and Epinephelus (Perciformes, Serranidae) from Thailand

Pseudorhabdosynochus suratthaniensis n. sp. is described from the gills of Cephalopholis argus; P. cephalopholi n. sp., from the gills of C. sonnerati; and P. samaesarnensis n. sp., from the gills of Epinephelus lanceolatus. These fish were all caught in the Gulf of Thailand. Pseudorhabdosynochus suratthaniensis n. sp. is distinguished from congeneric species by the structure of its sclerotized vagina, which has a wide sclerotized trumpet and a single large primary chamber, and by the number of rows of rodlets in each of its squamodiscs. Pseudorhabdosynochus cephalopholi n. sp. is also distinguished by the structure of its sclerotized vagina that, like the P. suratthaniensis n. sp., has a sclerotized trumpet, but it also has a long coiled or curved primary canal near its midlength, and a distal part with a primary chamber and a secondary chamber communicating with the primary chamber through a short secondary canal. In addition, P. cephalopholi n. sp. is distinguished by some sclerotized organs (ventral and dorsal hamuli, ventral bar, and quadriloculate organ) with different lengths, and by the number of rows of rodlets in each of its squamodiscs. Pseudorhabdosynochus samaesarnensis n. sp. is distinguished by its sclerotized vagina that has an anterior cup-shaped trumpet and a short straight or curved primary canal. For Thailand, these are the first species of Pseudorhabdosynochus described from species of Cephalopholis and the second species of Pseudorhabdosynochus described from Epinephelus.

Checklist of The Monogenea (Platyhelminthes) Parasitic in Tunisian Aquatic Vertebrates

153 species of monogeneans have been recorded in Tunisian aquatic vertebrates (89 hosts). A list of these species with hosts is presented. A comparison of the Monogenea diversity off the coast of Tunisia with other regions of the Mediterranean Sea and the world is provided. The number of parasites depends on the number of hosts examined and their diversity in the region. This list shows that Monopisthocotylea is the richest group. In addition, new records have been reported during a survey of the diversity of monogeneans fish in the southern coast of Tunisia (Gulf of Gabes) including: Benedenia monticellii (Parona and Perugia, 1895) Johnston, 1929, Lamellodiscus bidensEuzet, 1984, Lamellodiscus confusus Amine, Euzet & Kechemir-Issad, 2007, Lamellodiscus ergensi Euzet & Oliver, 1966, Lamellodiscus hiliiEuzet, 1984, Lamellodiscus imperviusEuzet, 1984, Lamellodiscus knoepffleri Oliver, 1969, Lamellodiscus theroni Amine, Euzet & Kechemir-Issad, 2007, Ligophorus acuminatus Euzet & Suriano, 1977, Ligophorus angustus Euzet & Suriano, 1977, Ligophorus heteronchus Euzet & Suriano, 1977, Ligophorus macrocolpos Euzet & Suriano, 1977, Ligophorus minimus Euzet & Suriano, 1977, Capsala maccallumi Price, 1939 and Pseudanthocotyloides heterocotyle (Van Beneden, 1871) Euzet & Prost, 1969.

Redescription, complete mitochondrial genome and phylogenetic relationships of Hexostoma thynni (Delaroche, 1811) Rafinesque, 1815 (Monogenea, Hexostomatidae)

Specimens of Hexostoma thynni (Delaroche, 1811) Rafinesque, 1815 were collected from their type-host, the bluefin tuna Thunnus thynnus, caught off Algeria, i.e. close to the type-locality, off Mallorca, which is also in the Mediterranean. The species is briefly redescribed and compared to previous descriptions, under the same name or as its synonym Plagiopeltis duplicata Diesing, 1858, to ascertain identity of specimens. The three genera within the Hexostomatidae (Hexostoma Rafinesque, 1815, Neohexostoma Price, 1961 and Homostoma Unnithan, 1965) are briefly discussed, with comments on the fragility of characters used to distinguish them. Using next-generation sequencing, the complete mitogenome and the cluster of ribosomal genes (SSU, LSU, ITS1, ITS2, 5.8S) were obtained. The mitogenome is 14,649 bp long and codes for 12 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes; its size is similar to other mitogenomes obtained from polyopisthocotylean monogeneans. A phylogeny based on concatenated mitogenome protein-coding genes from nine species of polyopisthocotylean monogeneans produced a tree in which the Hexostomatidae H. thynni was associated with other Mazocraeidea, such as Chauhaneidae and Diclidophoridae. This invalidates the hypothesis of Boeger & Kritsky (1993) of Hexostomatidae as sister-group to the Mazocraeidea and suggests the demise of the suborder Hexostomatinea Boeger & Kritsky, 1993. We insist on the usefulness of depositing parts of specimens used for molecular analyses, prepared on permanent slides, in a curated collection.

Truly a hyperparasite, or simply an epibiont on a parasite? The case of Cyclocotyla bellones (Monogenea, Diclidophoridae)

Cyclocotyla bellones Otto, 1823 (Monogenea, Diclidophoridae) is one of the few monogenean species reported as hyperparasitic: the worms dwell on cymothoid isopods, themselves parasites of the buccal cavity of fishes. We present here observations based on newly collected monogenean specimens from Ceratothoa parallela (Otto, 1828), an isopod parasite of Boops boops off Algeria and also investigated its diet to address whether Cy. bellones is indeed a hyperparasite, i.e., whether it feeds on the isopod. We also compared the body shape of various monogeneans belonging to the same family as Cy. bellones, the Diclidophoridae, including Choricotyle cf. chrysophryi Van Beneden & Hesse, 1863, collected from Pagellus acarne off Algeria. No morphological character of the anterior organs suggested any special adaptation in Cy. bellones to the perforation of the crustacean cuticle. The wall of the oesophagus and of the intestine of Cy. bellones was lined with a dark pigment similar to what is usually observed in haematophagous polyopisthocotyleans, and which is derived from ingested fish blood. We noticed that an anterior elongate stem exists only in diclidophorids dwelling on parasitic isopods and never in those attached to the gills. We hypothesize that the anterior stem of the body of Cy. bellones is an anatomical adaptation for the monogenean to feed on the fish while dwelling on the isopod. We thus consider that Cy. bellones is an epibiont of the parasitic crustacean, as it uses it merely as an attachment substrate, and is not a true hyperparasite.

A revision of Plectanocotyle (Monogenea, Plectanocotylidae), with molecular barcoding of three species and the description of a new species from the streaked gurnard Chelidonichthys lastoviza off Algeria

BACKGROUND

The family Plectanocotylidae includes parasites of the gills of marine fish; although nine genera and about 20 species have been described, almost no molecular information is available. Putting aside Plectanocotyle elliptica Diesing, 1850, supposedly a parasite of the white perch Morone americana, never found again since its original description, two species were valid within Plectanocotyle Diesing, 1850 before this work: Plectanocotyle gurnardi (Van Beneden & Hesse, 1863) Llewellyn, 1941 and Plectanocotyle major Boudaya, Neifar & Euzet, 2006.

METHODS

In this paper, we describe the third species of the genus Plectanocotyle and perform a comparative morphological and molecular analysis of the three species and of Triglicola obscura (Euzet & Suriano, 1974) Mamaev, 1976. Host fishes were also barcoded (COI) for confirmation of host identifications.

RESULTS

Plectanocotyle lastovizae n. sp. is described from the gills of the streaked gurnard Chelidonichthys lastoviza collected off Algeria. The species is compared with specimens of Plectanocotyle cf. gurnardi (from C. lastoviza) from the same locality and P. major and T. obscura (both from the longfin gurnard C. obscurus). Molecules from Plectanocotyle cf. gurnardi could not be compared with P. gurnardi from the type-host and type-locality and we kept the status of the Mediterranean specimens as pending. Algeria is a new geographic record for P. major and T. obscura. Plectanocotyle lastovizae n. sp. is distinguished from the other species found in the Mediterranean by the measurements of clamps, number of testes, and COI sequences, with notable divergence (7.8-11.8%) from the other two species of the genus.

DISCUSSION

We briefly present a list of currently known members of the family Plectanocotylidae, their biology and their hosts.

Novel molecular data for monogenean parasites of sparid fishes in the Mediterranean and a molecular phylogeny of the Microcotylidae Taschenberg, 1879

During a study of the monogeneans of four sparid fishes (Diplodus vulgaris, Pagellus bogaraveo, Pagrus pagrus and Sparus aurata) from the Western Mediterranean off Algeria, a large collection of parasites was characterised molecularly (28S rRNA and cox1 genes). A total of 46 partial sequences (23 for each gene) were generated from 38 isolates of monogeneans which included four species (Atrispinum acarne, Microcotyle erythrini (sensu stricto), Sparicotyle chrysophrii and Prostatomicrocotylinae gen. sp.) of the family Microcotylidae, two putative species of the family Capsalidae (Encotyllabe spp.), and one species (Choricotyle chrysophryi) of the family Diclidophoridae. Our study provides (i) the first molecular data for the Capsalidae in the Mediterranean; (ii) the first record of a member of the Prostatomicrocotylinae in the Mediterranean and in a sparid fish (D. vulgaris); (iii) the first cox1 sequences for A. acarne; (iv) the second record of M. erythrini (s.s.) from P. pagrus; and (v) the second confirmed by molecular data record of S. chrysophrii in wild populations of S. aurata. The first phylogenetic hypotheses for the family Microcotylidae developed here, revealed the monophyly of the subfamily Prostatomicrocotylinae and the genus Microcotyle but the relationships among the subfamilies were still largely unresolved with the best represented subfamily Microcotylinae being polyphyletic. Our results highlight the importance of molecular methods in the assessment of monogenean diversity and the need for a thorough taxon-sampling approach to increase the accuracy of phylogenetic reconstruction of the relationships of the large and taxonomically complex polyopisthocotylean family Microcotylidae.

Heteromicrocotyla polyorchis Unnithan, 1961 (Monogenea: Heteromicrocotylidae), a gill parasite of the yellow-spotted trevally, Carangoides fulvoguttatus (Carangidae) from Saudi Arabia: Morphology and phylogeny

Little information for parasitic infections of Carangoides fulvoguttatus was recorded. The present study was intended to investigate the gill parasite Heteromicrocotyla polyorchis of this fish and to provide a full morphological description and clarify its taxonomic status through phylogenetic analysis of the 28S rRNA gene region. A total of sixty fish specimens have been collected from the studied area (the Red Sea in Jeddah Province, Saudi Arabia) and gills were isolated and examined for identification of parasites. Using light electron microscopy, the recovered monogenean parasite's morphology was exhaustively characterized and described. Microscope examinations found that this parasite species represent Heteromicrocotyla polyorchis, and it could be distinguished from congeners of the same genus by armed genital atrium and cirrus sac, follicular post-ovarian testes, unique shape and number of clamps on both haptor sides, and the dorsally curved tip of the male copulatory organ. Morphological features were combined with molecular analysis of the 28S rRNA gene region. The selected gene for the isolated Heteromicrocotyla species was analyzed using appropriate primers to assist in phylogeny with those in the GenBank database. The present monogenean species was characterized by unique genetic sequences that were analyzed and deposited in the GenBank for the first time under the accession number MW406473. Phylogenetic analyses reported that the maximum identity between the current Heteromicrocotyla species and taxa of Heteromicrocotylidae was between 91.42 and 92.09% and confirmed its taxonomic status in this family with a well-distinct clade. The present study supported the second report of H. polyorchis as carangid fish ectoparasites and investigates the first appearance in C. fulvoguttatus inhabiting Saudi Arabia.

Redescription of Paradiplozoon opsariichthydis (Jiang, Wu et Wang 1984) Jiang, Wu et Wang, 1989 (Monogenea, Diplozoidae)

Paradiplozoon opsariichthydis (Jiang, Wu et Wang, 1984) Jiang, Wu et Wang, 1989 (Platyhelminthes, Monogenea, Diplozoidae) is blood-feeding parasite from the gills of Asian cyprinid fish Opsariichthys bidens Günther, 1873. In this study, we present a morphological redescription of P. opsariichthydis neotype main morphological features e.g. size of body and clamps due to the fact that the type material is missing. We decided to supplement morphological descriptions by the relevant molecular data (internal transcribed spacer - ITS2) related to P. opsariichthydis adult worm isolates and other representatives of genus Paradiplozoon to cross verify our findings. In addition to that, this study also brings an attention to the host identification. Thus, parasite data were complemented by the determinant cytochrome oxidase b (cytb) sequences of its hosts. All novel sequences are deposited in GenBank. This combination of the morphological and molecular data related to both the parasite and its host seems to be the optimal approach to the general process of (re)description of highly host-specific parasitic organisms, which can then lead to a meaningful phylogenetic analysis.

Triple barcoding for a hyperparasite, its parasitic host, and the host itself: a study of Cyclocotyla bellones (Monogenea) on Ceratothoa parallela (Isopoda) on Boops boops (Teleostei)

Cyclocotyla bellones Otto, 1823 (Diclidophoridae) is a monogenean characterised by an exceptional way of life. It is a hyperparasite that attaches itself to the dorsal face of isopods, themselves parasites in the buccal cavity of fishes. In this study, Cy. bellones was found on Ceratothoa parallela (Otto, 1828), a cymothoid isopod parasite of the sparid fish Boops boops off Algeria in the Mediterranean Sea. We provide, for the first time, molecular barcoding information of a hyperparasitic monogenean, the parasitic crustacean host, and the fish host, with COI sequences.

Four polyopisthocotyleans (Platyhelminthes: Monogenea) from carangid fishes in the Mediterranean, off the Algerian coasts

Four polyopisthocotyleans were collected from the gill filaments of carangids from off the Algerian coast, southern Mediterranean. Specimens of Gastrocotyle trachuri van Beneden & Hesse, 1863 (Gastrocotylidae) and Cemocotyle cf. trachuri Dillon & Hargis, 1965 (Heteraxinidae) from the Mediterranean horse mackerel Trachurus mediterraneus (Steindachner), Zeuxapta seriolae (Meserve, 1938) (Heteraxinidae) from the greater amberjack Seriola dumerili (Risso) and Pyragraphorus hollisae Euzet & Ktari, 1970 (Pyragraphoridae) from the pompano Trachinotus ovatus (Linnaeus) are redescribed based on newly collected specimens. Their taxonomically important morphological features (male copulatory organ and clamp sclerites) are described and illustrated, and the morphometric variation between Mediterranean and oceanic specimens is highlighted. Careful examination of the specimens of Cemocotyle Sproston, 1946 from the Mediterranean revealed that they exhibited unusual features compared with Cemocotyle trachuri Dillon & Hargis, 1965 from the Pacific, mainly the absence of the terminal lappet, thus questioning previous records of this species in the Mediterranean. New geographical locality records are provided for Z. seriolae and P. hollisae. The presence of C. cf. trachuri and Z. seriolae in the Mediterranean is noteworthy as these monogeneans were initially described in the Pacific Ocean. This study extends the geographical range of Z. seriolae to the southern Mediterranean.

Zschokkella epinepheli n. sp. (Myxosporea: Myxidiidae) infecting the gallbladder of the white grouper Epinephelus aeneus (Serranidae) from Tunisian waters

A new coelozoic myxosporean species, Zschokkella epinepheli n. sp., collected from the gallbladder of the white grouper Epinephelus aeneus (Perciformes: Serranidae) from the bay of Bizerte, Tunisia, is described based on morphological and molecular characteristics. Myxospores and plasmodia were observed floating free in the bile. Mature plasmodia were polysporic and subspherical in shape, measuring 85.0-94.0 μm long and 70.0-82.0 μm wide. Mature myxospores were ovoid in valvular view, measuring 10.0 ± 1.7 (8.0-11.0) μm in length and 7.0 ± 0.3 (6.6-7.5) μm in width. Polar capsules were pyriform and equal in size, measuring 3.0 ± 0.2 (2.8-3.6) μm in length and 2.3 ± 0.3 (1.8-2.7) μm in width. Myxospore valves had 12-14 longitudinal striations. Based on the small subunit rDNA, the new species Z. epinepheli n. sp. differs from all other Zschokkella species for which there is a DNA sequence deposited in GenBank. Phylogenetic analysis revealed that Z. epinepheli n. sp. clustered in the marine subclade of Zschokkella species within the biliary tract IV clade. This is the first report of a Zschokkella species from the gallbladder of an epinephelin fishes.

Redescription of Flexophora ophidii Prost & Euzet, 1962 (Monogenea: Diclidophoridae) from Ophidion barbatum (Ophidiidae) off the Algerian coast, Mediterranean Sea

The diclidophorid Flexophora ophidii Prost & Euzet, 1962, the type- and only species of the genus Flexophora Prost & Euzet, 1962, has never been redescribed neither reported since its original description. The latest lacked a diagnosis of the genus that remains unavailable to date. Flexophora ophidii is redescribed and illustrated based on examination of new material from the type-host Ophidion barbatum L. (Ophidiiformes: Ophidiidae) collected off the Algerian coast (new geographical record), southern Mediterranean. A diagnosis of the genus is provided.

No vagina, one vagina, or multiple vaginae? An integrative study of Pseudaxine trachuri (Monogenea, Gastrocotylidae) leads to a better understanding of the systematics of Pseudaxine and related genera

The presence/absence and number of vaginae is a major characteristic for the systematics of the Monogenea. Three gastrocotylid genera share similar morphology and anatomy but are distinguished by this character: Pseudaxine Parona & Perugia, 1890 has no vagina, Allogastrocotyle Nasir & Fuentes Zambrano, 1983 has two vaginae, and Pseudaxinoides Lebedev, 1968 has multiple vaginae. In the course of a study of Pseudaxine trachuri Parona & Perugia 1890, we found specimens with structures resembling "multiple vaginae"; we compared them with specimens without vaginae in terms of both morphology and molecular characterisitics (COI barcode), and found that they belonged to the same species. We also investigated the male copulatory organ (MCO) of this species, the accuracy of the original description of which is known to be a matter of debate. We found that the genital atrium is armed with 12 hooks arranged as a single circle and a central hollow stylet which is probably involved in traumatic insemination. We redescribed Pseudaxine trachuri based on newly collected specimens from off the coast of Algeria and Museum specimens from off France. Specimens from the type-host, Trachurus trachurus, were found to be similar, for both molecular sequences and morphology, to those found on Boops boops. We can therefore confirm, for the first time with molecular evidence, that B. boops is a host of this parasite. We consider that Pseudaxinoides was erected on the basis of an erroneous interpretation of structures which are not vaginae and, consequently, propose the transfer of most of its species to Pseudaxine, as P. australis (Lebedev, 1968) n. comb., P. bychowskyi (Lebedev, 1977) n. comb., P. caballeroi (Lebedev, 1977) n. comb., P. cariacoensis (Nasir & Fuentes-Zambrano, 1983) n. comb., and P. vietnamensis (Lebedev, Parukhin & Roitman, 1970) n. comb. We also propose Allogastrocotyle dillonhargisorum nom. nov. for Pseudaxine bivaginalis Dillon & Hargis, 1965 to avoid a secondary homonymy.

Pseudorhabdosynochus kasetsartensis n. sp. (Monogenea: Diplectanidae) from the cloudy grouper Epinephelus erythrurus (Valenciennes) (Perciformes: Serranidae) in the lower Gulf of Thailand

Pseudorhabdosynochus kasetsartensis n. sp. is described from the gills of the cloudy grouper Epinephelus erythrurus (Valenciennes) caught in the lower Gulf of Thailand. The new species is distinguished from other species assigned to the genus by the structure of its sclerotised vagina which has a wide and prominent sclerotised trumpet, long, thin, coiled or curved primary canal, short secondary canal, and primary and secondary chambers that are blind extremities of the primary and secondary canals, respectively. This is the first species of Pseudorhabdosynochus Yamaguti, 1958 described from E. erythrurus and the first record of a species of Pseudorhabdosynochus in Thailand.

Redescription and molecular characterisation of Allogastrocotyle bivaginalis Nasir & Fuentes Zambrano, 1983 (Monogenea: Gastrocotylidae) from Trachurus picturatus (Bowdich) (Perciformes: Carangidae) off the Algerian coast, Mediterranean Sea

Allogastrocotyle bivaginalis Nasir & Fuentes Zambrano, 1983, the sole species of Allogastrocotyle Nasir & Fuentes Zambrano, 1983, was described from Trachurus lathami Nichols off Venezuela and never recorded since. We found monogeneans on Trachurus picturatus (Bowdich) (Carangidae) off the Algerian coast, Mediterranean Sea, which had the characteristics of the genus, including, especially, paired vaginae. We compared them to the single available specimen of A. bivaginalis, the holotype. Unfortunately, this holotype does not show clamp structure and soft internal anatomy. Our specimens were similar to A. bivaginalis in most characteristics such as body shape, vaginal openings, and number of testes, clamps and hooks in genital atrium. We detected minor differences in clamp structure but could not ascertain if these were the result of incomplete observations in the original description of real morphological differences. The host fish of our specimens were barcoded (cox1) confirming their specific identity. A phylogenetic analysis of cox1 sequences showed that our sequences of A. bivaginalis were distinct from those of Pseudaxine trachuri Parona & Perugia, 1889 (distance > 15%) and of several other gastrocotylids. Finally, we could not distinguish our Mediterranean specimens from A. bivaginalis, neither on the base of morphology (because the original description is incomplete) nor on molecules (because molecular information is lacking on A. bivaginalis from Venezuela) and ascribe them to A. bivaginalis. However, hosts are different, and localities are widely separated, so it is likely that future study will show that the species from the Mediterranean is a distinct, new, species.

Holocephalocotyle monstrosae n. gen. n. sp. (Monogenea, Monocotylidae) from the olfactory rosette of the rabbit fish, Chimaera monstrosa (Holocephali, Chimaeridae) in deep waters off Algeria

Based on a molecular and morphological study, a new monocotylid genus, Holocephalocotyle n. gen. is proposed to accommodate Holocephalocotyle monstrosae n. sp., found on the olfactory rosette of the rabbit fish, Chimaera monstrosa Linnaeus (Chondrichthyes, Chimaeridae), from the Mediterranean Sea off Algeria. Identification of fish hosts was confirmed by molecular barcoding of the COI gene. A partial 28S rDNA sequence (D1-D2 domain) of Holocephalocotyle monstrosae was obtained; it was distinct from all known monocotylid sequences (p-distance: 15.5-23%). A phylogenetic tree constructed from available monocotylid sequences showed that Holocephalocotyle monstrosae was included, and basal, in a robust group including species of Merizocotyle, Mycteronastes and Empruthotrema, confirming that the species is a member of the Merizocotylinae. The new genus is unique among the Merizocotylinae in having a distinctive pattern of haptoral loculi with one central, five peripheral and seven "interperipheral loculi" partially inserted between peripheral loculi and a compartmentalised sclerotised male copulatory organ. The diagnosis of the Merizocotylinae is amended to include this new genus. The new genus represents the second monocotylid genus recorded from holocephalans.

Towards the resolution of the Microcotyle erythrini species complex: description of Microcotyle isyebi n. sp. (Monogenea, Microcotylidae) from Boops boops (Teleostei, Sparidae) off the Algerian coast

The monogenean Microcotyle erythrini is atypical because it has been recorded from several fish host species in the Mediterranean Sea and Atlantic Ocean, in contrast to many species which are considered strictly specific. This could indicate a true lack of specificity or that several cryptic species are involved. This paper is a partial attempt to solve this problem. Specimens of a monogenean resembling M. erythrini were collected from bogues, Boops boops, caught off Algeria. A comparison with published descriptions and with museum specimens of M. erythrini did not yield any clear morphological difference. However, sequences of cytochrome c oxidase subunit I (COI) differed by 16.3% from that of M. erythrini (from GenBank, material collected from the type-host Pagellus erythrinus), indicating that the species was different. The species from B. boops is therefore described here as Microcotyle isyebi n. sp. and differential diagnoses with Microcotyle species from the Mediterranean and from sparids are provided. These results suggest that a molecular re-evaluation of other M. erythrini-like specimens from various fish hosts could reveal the existence of additional parasite biodiversity.

Microcotyle visa n. sp. (Monogenea: Microcotylidae), a gill parasite of Pagrus caeruleostictus (Valenciennes) (Teleostei: Sparidae) off the Algerian coast, Western Mediterranean

Parasite biodiversity of fish of the southern part of the Mediterranean sea is still incompletely explored. We describe here Microcotyle visa n. sp. from the gill filaments of the bluespotted seabream Pagrus caeruleostictus (Valenciennes) (Sparidae) collected off the Algerian coast. The identity of fish hosts was confirmed by barcoding. Microcotyle visa n. sp. is herein described and illustrated. Analysis of the cox1 gene of the monogeneans revealed minor intraspecific variation (1.4%), an order of magnitude lower than the distance between this species and other Microcotyle species (10-15 %). Microcotyle visa n. sp. is distinguished from Microcotyle erythrini van Beneden & Hesse, 1863, a congener infesting sparids, on the basis of morphological (size of clamps, number of testes) and molecular (cox1) differences. This is the fourth member of the genus known to parasitise a sparid host. A species of Paramicrocotyle sp. included in the molecular analysis was nested within a robust Microcotyle + Paramicrocotyle clade; in the absence of demonstrated molecular and morphological differences, we consider that Paramicrocotyle Caballero & Bravo-Hollis, 1972 is a junior synonym of Microcotyle van Beneden & Hesse, 1863 and transfer two species of Paramicrocotyle as Microcotyle danielcarrioni (Martinez & Barrantes, 1977) n. comb. and Microcotyle moyanoi (Villalba & Fernandes, 1986) n. comb.

Lessepsian migration and parasitism: richness, prevalence and intensity of parasites in the invasive fish Sphyraena chrysotaenia compared to its native congener Sphyraena sphyraena in Tunisian coastal waters

Background

Parasites can play various roles in the invasion of non-native species, but these are still understudied in marine ecosystems. This also applies to invasions from the Red Sea to the Mediterranean Sea via the Suez Canal, the so-called Lessepsian migration. In this study, we investigated the role of parasites in the invasion of the Lessepsian migrant Sphyraena chrysotaenia in the Tunisian Mediterranean Sea.

Methods

We compared metazoan parasite richness, prevalence and intensity of S. chrysotaenia (Perciformes: Sphyraenidae) with infections in its native congener Sphyraena sphyraena by sampling these fish species at seven locations along the Tunisian coast. Additionally, we reviewed the literature to identify native and invasive parasite species recorded in these two hosts.

Results

Our results suggest the loss of at least two parasite species of the invasive fish. At the same time, the Lessepsian migrant has co-introduced three parasite species during the initial migration to the Mediterranean Sea, that are assumed to originate from the Red Sea of which only one parasite species has been reported during the spread to Tunisian waters. In addition, we found that the invasive fish has acquired six parasite species that are native in the Mediterranean Sea. However, parasite richness, prevalence and intensity were overall much lower in the invasive compared to the native fish host in the Mediterranean Sea.

Discussion

These results suggest that the Lessepsian migrant may affect native fish hosts by potentially altering the dynamics of native and invasive parasite-host interactions via parasite release, parasite co-introduction and parasite acquisition. They further suggest that the lower infection levels in the invasive fish may result in a competitive advantage over native fish hosts (enemy release hypothesis). This study demonstrates that cross-species comparisons of parasite infection levels are a valuable tool to identify the different roles of parasites in the course of Lessepsian migrations.

Species of Philometra (Nematoda, Philometridae) from fishes off the Mediterranean coast of Africa, with a description of Philometra rara n. sp. from Hyporthodus haifensis and a molecular analysis of Philometra saltatrix from Pomatomus saltatrix

Two gonad-infecting species of Philometra Costa, 1845 (Nematoda, Philometridae) were recorded for the first time from marine perciform fishes off Tunisia and Libya: Philometra rara n. sp. from the rare, deep-water Haifa grouper Hyporthodus haifensis (Serranidae) off Libya and Philometra saltatrix Ramachandran, 1973 from the bluefish Pomatomus saltatrix (Pomatomidae) off Tunisia. Identification of both fish species was confirmed by molecular barcoding. Light and scanning electron microscope studies of Ph. rara n. sp. showed that it is characterized by the length of spicules (216–219 μm) and the gubernaculum (90–93 μm), the gubernaculum/spicules length ratio (1:2.32–2.43), and mainly by the shape and structure of the distal end of the gubernaculum (shovel-shaped with a wide median smooth field in dorsal view), appearing as having a dorsal protuberance in lateral view, and by the structure of the male caudal mound (dorsally interrupted); large subgravid females (70–137 mm long) are characterized by the presence of four oval submedian cephalic elevations, each of them bearing a pair of cephalic papillae of the outer circle. The finding of Ph. saltatrix off Tunisia confirms that this species is widespread throughout the Mediterranean region. A molecular analysis of our Ph. saltatrix specimens and other available philometrid cytochrome c oxidase 1 (COI) sequences showed that most species have robust clades. Sequences of Ph. saltatrix from Tunisia diverge from Ph. saltatrix from Brazil and the USA, suggesting that speciation is currently occurring between populations from both sides of the Atlantic Ocean.

Diplectanids from Mycteroperca spp. (Epinephelidae) in the Mediterranean Sea: Redescriptions of six species from material collected off Tunisia and Libya, proposal for the 'Pseudorhabdosynochus riouxi group', and a taxonomic key

Diplectanid monogeneans are gill parasites that can infect fish in huge numbers and thus become harmful, especially in maricultured fish. It is therefore useful to have taxonomic tools, such as keys, to identify species. The following diplectanid species from groupers of the Mediterranean Sea were studied: five species of Pseudorhabdosynochus Yamaguti, 1958, including P. riouxi (Oliver, 1986) Kritsky & Beverley-Burton, 1986 from the dusky grouper Mycteroperca marginata, P. enitsuji Neifar & Euzet, 2007, P. bouaini Neifar & Euzet, 2007, P. dolicocolpos Neifar & Euzet, 2007 and P. sinediscus Neifar & Euzet, 2007 from the goldblotch grouper M. costae, and Echinoplectanum echinophallus (Euzet & Oliver, 1965) Justine & Euzet, 2006 from the dusky grouper. New material was obtained from fish collected from off Tunisia and Libya and compared to the type-material and voucher specimens in museum collections. Identifications of fish were confirmed by barcoding of cytochrome c oxidase subunit I (COI) sequences. The sclerotized vagina was considered the most important structure for systematics. The three species P. riouxi, P. bouaini, and P. enitsuji share a common general structure of the sclerotized vagina with a conspicuous spherical secondary chamber. We thus propose the 'Pseudorhabdosynochus riouxi group' to accommodate them. Pseudorhabdosynochus dolicocolpos has an elongate vaginal structure that is completely different from all its congeneric species reported from the Mediterranean Sea, and Pseudorhabdosynochus sinediscus has a sclerotized vagina in which the secondary chamber is not visible, and a haptor without squamodiscs. A taxonomic key to diplectanid species on Mycteroperca spp. in the Mediterranean Sea is proposed; it includes ten species of Pseudorhabdosynochus and one species of Echinoplectanum.

A new species of Microcotyle (Monogenea: Microcotylidae) from Scorpaena notata (Teleostei: Scorpaenidae) in the Mediterranean Sea

We collected specimens of Microcotyle spp. from two species of scorpaeniform fishes off Algeria, namely Scorpaena notata and Helicolenus dactylopterus. The identification of both fishes was confirmed by molecular barcoding of the COI gene. Sequences of COI gene were also obtained for both parasite species. The species from S. notata is described as Microcotyle algeriensis n. sp., on the basis of morphological differences from other species (number of clamps, number of spines in genital atrium, number of testes). Its COI sequence differs from M. sebastis Goto, 1894 (from Sebastes schlegeli from a fish farm in South Korea) by 14.6%. The species from H. dactylopterus is distinct from M. algeriensis on the basis of morphology (number of clamps, number of spines in genital atrium) and COI sequence (4.5% divergence) and is also distinct from M. sebastis in its COI sequence (12.3%). We refrained from describing it as new because M. sebastis, a species originally described from scorpaeniform fishes off Japan, has been recorded in various hosts in the North and South Pacific, Atlantic and Mediterranean (for the latter, in the same host, H. dactylopterus). We believe that correct specific assignment of species of Microcotyle from scorpaeniform fishes needs a detailed morphological and molecular study of representatives from various locations and hosts.

Species of Pseudorhabdosynochus (Monogenea, Diplectanidae) from Groupers (Mycteroperca spp., Epinephelidae) in the Mediterranean and Eastern Atlantic Ocean, with Special Reference to the 'Beverleyburtonae Group' and Description of Two New Species

Pseudorhabdosynochus Yamaguti, 1958 is a species-rich diplectanid genus, mainly restricted to the gills of groupers (Epinephelidae) and especially abundant in warm seas. Species from the Mediterranean are not fully documented. Two new and two previously known species from the gills of Mycteroperca spp. (M. costae, M. rubra, and M. marginata) in the Mediterranean and Eastern Atlantic Ocean are described here from new material and slides kept in collections. Identifications of newly collected fish were ascertained by barcoding of cytochrome c oxidase subunit I (COI) sequences. Pseudorhabdosynochus beverleyburtonae (Oliver, 1984) Kritsky & Beverley-Burton, 1986 and P. sosia Neifar & Euzet 2007 are redescribed from type-specimens and new specimens collected off Tunisia and Libya from M. marginata and M. costae, respectively. Pseudorhabdosynochus oliveri n. sp., from M. marginata (type-host) off the Mediterranean coast of France (type-locality), is described from specimens found among voucher specimens of P. beverleyburtonae deposited by Guy Oliver in the collection of the Muséum National d’Histoire Naturelle, Paris. Pseudorhabdosynochus oliveri is distinguished by the shape of its sclerotised vagina; it was not found in the other localities investigated. Pseudorhabdosynochus hayet n. sp. is described from M. rubra (type host) off Senegal (type-locality) and Tunisia. Pseudorhabdosynochus hayet is morphologically similar to P. sosia (type-host: M. costae) but was distinguished by differences in measurements of the vagina and male copulatory organ, different host, and divergent COI sequences. The four species (P. beverleyburtonae, P. sosia, P. oliveri, and P. hayet) share common characteristics such as squamodiscs with 2 innermost circular rows of rodlets and a similar general structure of the sclerotised vagina; we propose to group them into a ‘beverleyburtonae group’ within Pseudorhabdosynochus.