First recorded occurrence of the parasitic barnacle (Anelasma squalicola) on a Greenland shark (Somniosus microcephalus) in the Canadian Arctic.

A solitary Anelasma squalicola specimen was collected from the cloaca of a Greenland shark (Somniosus microcephalus), the first time this association has been recorded. The specimen's identity was confirmed through morphological and genetic assessment (mitochondrial markers: COI and control region). A. squalicola is a species typically associated with deep-sea lantern sharks (Etmopteridae) and, until the present observation, had never been observed at a sexually mature size in the absence of a mating partner. Given the reported negative effects of this parasite on its hosts, monitoring Greenland sharks for additional cases is recommended.

The Current State of Knowledge on Parasitic Copepods (Siphonostomatoida: Pandaridae) of Elasmobranchs.

Elasmobranch fishes comprise sharks and sawfish (infraclass Selachii), and rays, skates, and stingrays (infraclass Batoidea). Many elasmobranch species are popular fish exhibited in zoos and public aquariums. They may serve as hosts for a great variety of parasites. Among these, parasitic copepods are commonly known to cause serious damage to their hosts. In this paper, we summarize and analyse the existing literature on the pandarid copepods (Siphonostomatoida Burmeister, 1835) of elasmobranch fishes, as it relates to their diversity, life cycles, host-specificity, biogeography, pathology, and available treatments.

Parasites and prey of the nursehound shark Scyliorhinus stellaris (Linnaeus, 1758): Insights into hidden trophic web interactions in the Mediterranean Sea.

The metazoan parasite community and the stomach contents of the nursehound shark Scyliorhinus stellaris from the Gulf of Naples (central Mediterranean Sea) were studied. The nursehound shark harboured a poor parasite community composed of a species of gill monogenean (Hexabothrium appendiculatum) and three intestinal cestode taxa (Acanthobothrium coronatum and two unidentified species of the genera Yamaguticestus and Scyphophyllidium), all represented by adult stages. Hosts were mostly parasitized by individuals of A. coronatum, which was the most abundant species and contributed to almost 80% of the total number of parasites found. Conversely, other trophically transmitted parasites (i.e., Yamaguticestus sp. and Scyphophyllidium sp.) showed low prevalence and abundance. The parasite infracommunity was poor, showing low values of species richness, total mean abundance, and diversity indices. Overall, 52 prey items belonging to 13 taxa were identified in the stomach contents. Cephalopods were the most important prey items (represented by nine taxa) and the most diverse and abundant group. In the multivariate space provided by a principal component of mixed data (PCAmix), nursehound sharks distributed along two main axes, related to individual traits (first axis) and stomach contents (including empty ones, second axis). A logistic regression based on the first two axes of the PCAmix showed a significant influence of host individual traits and, to a lesser extent, of stomach contents, regarding the probability of being infected by A. coronatum. Alongside specific traits already associated with parasites transmission, our results highlight the importance of cephalopods in transferring cestode infections through trophic web interactions in the top-predator nursehound shark.

Elasmobranchs from Indonesian Waters: Feeding Ecology and Trypanorhynch Cestode Fauna Composition to Support Efforts in Shark and Ray Conservation.

PURPOSE: The stomachs and spiral valves of sharks and rays were examined for their trypanorhynch (Cestoda) parasite fauna and dietary items to infer feeding ecology. In Indonesia, sharks and rays have been experiencing increasing awareness and conservation in the recent years due to high fisheries activities and to avoid future species extinction. METHODS: The samples were collected in 2009 from two different sampling sites at the southern coasts of Java and Bali in Indonesia. The parasite fauna was studied for 41 elasmobranch fishes. Amongst these, three shark species, Carcharhinus sorrah, Carcharhinus sp. I and Squalus megalops and seven ray species, Brevitrygon heterura, B. cf. heterura, Gymnura zonura, Maculabatis gerrardi, Mobula kuhlii, Neotrygon cauruleopuncatata and Rhinobatos penggali were studied. Four additional specimens, belonging to the shark species Carcharhinus sp. II and Mustelus cf. manazo and the ray species Maculabatis gerrardi were studied from the waters of South Bali. RESULTS: Analyses of the feeding ecology of the ray M. gerrardi revealed distinct differences between both sampling sites, indicating the presence of ecological differences between the geographically independent regions. A total of 11 different trypanorhynch species/taxa belonging to the five families Eutetrarhynchidae (5), Gilquiniidae (1), Lacistorhynchidae (1), Pterobothriidae (1) and Tentaculariidae (3) were found. Ten trypanorhynch species from Penyu Bay and four species from South Bali could be identified. Two taxa that might represent new species were collected: Dollfusiella sp. from Brevitrygon heterura and Prochristianella sp. from Maculabatis gerrardi. CONCLUSIONS: The present paper gives insights in using the trypanorhynch cestode community in combination with feeding ecology analyses to support conservation of elasmobranchs in Indonesian waters.

Pathology associated with Tripaphylus Richiardi, 1878 infection (Copepoda: Sphyriidae) in wild-caught Australian blackspot sharks, Carcharhinus coatesi (Whitley, 1939), off northern Australia.

Female specimens of the newly described mesoparasitic copepod Tripaphylus squidwardi (Sphyriidae), collected from the Australian blackspot shark, Carcharhinus coatesi, off northern Australia were examined histologically. The 'encapsulated' head of the copepod was found in the ventral musculature of the throat of the shark. The head of the copepod was surrounded by a tissue capsule of unknown origin. There were signs of chronic inflammation associated with the infection, although there appeared to be no effect on the health of the shark.

Unravelling the trophic interaction between a parasitic barnacle (Anelasma squalicola) and its host Southern lanternshark (Etmopterus granulosus) using stable isotopes.

The parasitic barnacle, Anelasma squalicola, is a rare and evolutionary fascinating organism. Unlike most other filter-feeding barnacles, A. squalicola has evolved the capability to uptake nutrient from its host, exclusively parasitizing deepwater sharks of the families Etmopteridae and Pentanchidae. The physiological mechanisms involved in the uptake of nutrients from its host are not yet known. Using stable isotopes and elemental compositions, we followed the fate of nitrogen, carbon and sulphur through various tissues of A. squalicola and its host, the Southern lanternshark Etmopterus granulosus, to better understand the trophic relationship between parasite and host. Like most marine parasites, A. squalicola is lipid-rich and clear differences were found in the stable isotope ratios between barnacle organs. It is evident that the deployment of a system of 'rootlets', which merge with host tissues, allows A. squalicola to draw nutrients from its host. Through this system, proteins are then rerouted to the exterior structural tissues of A. squalicola while lipids are used for maintenance and egg synthesis. The nutrient requirement of A. squalicola was found to change from protein-rich to lipid-rich between its early development stage and its definitive size.

Hexabothriidae and Monocotylidae (Monogenoidea) from the gills of neonate hammerhead sharks (Sphyrnidae) Sphyrna gilberti, Sphyrna lewini and their hybrids from the western North Atlantic Ocean.

Neonates of hammerhead sharks (Sphyrnidae), Sphyrna lewini (Griffith and Smith, 1834), the sympatric cryptic species, Sphyrna gilberti Quattro et al., 2013, and their hybrids were captured in the western North Atlantic, along the coast of South Carolina, USA, between 2018 and 2019 and examined for gill monogenoids. Parasites were identified and redescribed from the gills of 79 neonates, and DNA sequences from partial fragments of the nuclear 28S ribosomal RNA (rDNA) and cytochrome c oxidase I mitochondrial DNA (COI) genes were generated to confirm species identifications. Three species of monogenoids from Hexabothriidae Price, 1942 and Monocotylidae Taschenberg, 1879 were determined and redescribed. Two species of Hexabothriidae, Erpocotyle microstoma (Brooks, 1934) and Erpocotyle sphyrnae (MacCallum, 1931), infecting both species of Sphyrna and hybrids; and 1 species of Monocotylidae, Loimosina wilsoni Manter, 1944, infecting only S. lewini and hybrids. Loimosina wilsoni 28S rDNA sequences matched those of Loimosina sp. from the southern coast of Brazil. Based on limited morphological analysis, Loimosina parawilsoni is likely a junior synonym of L. wilsoni. This is the first taxonomic study of monogenoids infecting S. gilberti and hybrids of S. gilberti and S. lewini.

Morphological and molecular characterization of Paraleptus chiloscyllii Yin & Zhang, 1983 (Nematoda: Physalopteridae) from the brownbanded bambooshark Chiloscyllium punctatum Müller & Henle (Elasmobranchii: Orectolobiformes).

Paraleptus (Spirurida: Physalopteridae) is a small genus of nematodes, parasitic in fishes, most species of which are inadequately described. Genetic data for these congeners have not been reported. The detailed morphology of P. chiloscyllii was studied using light and scanning electron microscopy, based on newly collected specimens from the brownbanded bambooshark C. punctatum Müller & Henle (Elasmobranchii: Orectolobiformes) in the Taiwan Strait. Some previously unreported morphological features of taxonomic significance were observed, i.e., pseudolabium with two sublateral rows of 6-7 small spines, 7-8 small spines on each lower rim between pseudolabia, deirids not distally bifurcated, vulva with remarkable protruding lip, presence of 1 pair medio-ventral precloacal papillae and 1 pair of discoid protrusions of postcloacal lip in male. The specimens described by González-Solís & Ali's (2015) as P. chiloscyllii from the Arabian carpetshark C. arabicum off Iraq are considered a new species, for which the name P. moraveci n. sp. is proposed. The genetic characterization of the partial small (18S) and large (28S) ribosomal DNA, and the partial mitochondrial cytochrome c oxidase subunit 1 (cox1) of P. chiloscyllii are provided for the first time. There was no intraspecific nucleotide divergence detected in the 18S and 28S regions among different individuals of P. chiloscyllii, but a low level of intraspecific genetic variation was found in the cox1 (0.62-0.92%). The present genetic data is very important for molecular identification, and will be valuable for further invertigantions on the population genetics and phylogeny of this group.

REDESCRIPTION OF CATHARIOTREMA SELACHII (MACCALLUM, 1916) JOHNSTON AND TIEGS, 1922 (MONOGENOIDEA: MONOCOTYLIDAE), EMENDATION OF MONOTYPIC CATHARIOTREMA JOHNSTON AND TIEGS, 1922, AND PROPOSAL OF CATHARIOTREMATINAE N. SUBFAM. BASED ON MORPHOLOGICAL AND NUCLEOTIDE EVIDENCE.

We herein redescribe the enigmatic Cathariotrema selachii (MacCallum, 1916) Johnston and Tiegs, 1922 based on the holotype, paratypes, and newly collected specimens infecting the olfactory organ of 5 shark species from the Gulf of Mexico (all new host records): scalloped hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834) (Carcharhiniformes: Sphyrnidae); great hammerhead shark, Sphyrna mokarran (Rüppell, 1837); blacktip shark, Carcharhinus limbatus (Müller and Henle, 1839) (Carcharhiniformes: Carcharhinidae); spinner shark, Carcharhinus brevipinna (Müller and Henle, 1839); and Atlantic sharpnose shark, Rhizoprionodon terraenovae (Richardson, 1836) (Carcharhinidae). These specimens were morphologically indistinguishable from each other and from MacCallum's holotype and paratypes. Those sequenced had identical first internal transcribed spacer (ITS1) and large subunit ribosomal DNA (28S) nucleotide sequences. As such, C. selachii infects sharks of 2 orders (Carcharhiniformes, Lamniformes) and 3 families (Carcharhinidae, Sphyrnidae, Lamnidae) in the Northwestern Atlantic Ocean (type locality) and Gulf of Mexico (new records herein). This report is the first of new specimens of C. selachii in the Atlantic Ocean Basin in 95 yr and corrects long-standing error cascades and ambiguities concerning the morphology and systematic placement of C. selachii. Considering morphology and nucleotide-based phylogenetic evidence (28S, Bayesian analysis), we herein emend monotypic CathariotremaJohnston and Tiegs, 1922 and propose Cathariotrematinae Bullard n. subfam. for it and 4 other genera (all formerly assigned to Merizocotylinae Johnston and Tiegs, 1922). These genera comprise species infecting only the nose of sharks (monotypic Cathariotrema, SqualotremaKearn and Green, 1983 and SeptitremaKheddam, Chisholm, and Tazerouti, 2020 plus 3 species of TriloculotremaKearn, 1993) and nose of a chimaera (monotypic HolocephalocotyleDerouiche, Neifar, Gey, Justine, and Tazerouti, 2019). Cathariotrematinae differs from Merizocotylinae by having a 3-part attachment organ and by lacking open loculi that symmetrically encircle a cluster of >2 loculi in the center of the haptor. Monophyletic Cathariotrematinae (with sequences representing species of Cathariotrema, Triloculotrema, and Holocephalocotyle only) was sister to monophyletic Merizocotylinae, which together were sister to monophyletic Calicotylinae Monticelli, 1903. These subfamilies comprise a monophyletic group of monocotylids that have a double vagina and infect extrabranchial, enclosed niches (urogenital system, body cavity, olfactory chamber/nose) on their shark, ray, and chimaera hosts (all other monocotylids have a single vagina and infect the gill or body surfaces of rays only). Monocotylinae Taschenberg, 1879 and Decacotylinae Chisholm, Wheeler, and Beverley-Burton, 1995 were recovered as monophyletic. Heterocotylinae Chisholm, Wheeler, and Beverley-Burton, 1995 remained paraphyletic. We accept ParacalicotyleSzidat, 1970.

Three new species of 'tetraphyllidean' cestodes from an undescribed bamboo shark (Orectolobiformes: Hemiscylliidae) in Sri Lanka.

Examination of seven specimens of an undescribed species of bamboo shark (Orectolobiformes: Hemiscylliidae), currently referred to as Chiloscyllium sp. 1, from Sri Lanka yielded three new species of 'tetraphyllidean' cestodes, one each in the genera Carpobothrium Shipley et Hornell, 1906, Spiniloculus Southwell, 1925, and Yorkeria Southwell, 1927. Carpobothrium marjorieae Caira, Otto et Jensen sp. n. differs from its three valid congeners in total length, number of testes, and size of the apical sucker of its anterior bothridial flap. Like Carpobothrium eleanorae Koontz et Caira, 2016 it possesses spherical eggs with highly elongate bipolar filaments, but its eggs are conspicuously larger than those of the latter species. Spiniloculus akshayi Caira, Otto et Jensen sp. n. can be distinguished from its five congeners in total length and number of proglottids. Yorkeria sachiniae Caira, Otto et Jensen sp. n. differs from its 16 congeners in number of proglottids and testes, total length, terminal proglottid, cirrus sac, and cephalic peduncle length, hook size, genital pore position, and bothridial shape. The eggs of Y. sachiniae Caira, Otto et Jensen sp. n. are spindle-shaped and bear a single long, polar filament. All three species were found to exhibit microthrix patterns on their scolices like those of the majority of their congeners that have been examined to date with scanning electron microscopy. Microtriches on the distal surfaces of the bothridial pouches of a species of Carpobothrium were characterised for the first time; C. marjorieae Caira, Otto et Jensen sp. n. was found to possess a modified form of gladiate spinithrix on this surface. Among the seven members of the genus, this is the first species of Chiloscyllium Müller et Henle that has been found to host representatives of all three of these 'tetraphyllidean' genera. However, unlike most of its congeners, a representative of the non-hooked genus Scyphophyllidium Woodland, 1927 was not found infecting Chiloscyllium sp. 1.

First record of the parasitic barnacle Anelasma squalicola Darwin, 1852 (Pollicipedomorpha: Pollicipedidae) in the Eastern Pacific Ocean and a new host report: Etmopterus benchleyi Vsquez, Ebert amp; Long, 2015 (Squaliformes: Etmopteridae).

Anelasma squalicola is a parasitic barnacle of members of the deep-water shark families Etmopteridae, Pentanchidae and Scyliorhinidae. We report the first published confirmation of this species in the Eastern Pacific Ocean, based on material collected off Costa Rica, its first record as a parasite of the Ninja lantern shark, Etmopterus benchley (Etmopteridae), and a new size record for the host. The information presented herein expands the knowledge (distribution and host usage) of this enigmatic species.

A NEW SPECIES OF ACANTHOBOTHRIUM (CESTODA: ONCHOPROTEOCEPHALIDEA) FROM THE SMALLEYE PYGMY SHARK, SQUALIOLUS ALIAE (CHONDRICHTHYES: SQUALIFORMES: DALATIIDAE), FROM TAIWAN.

The cestode fauna of Squaliolus aliae was examined for the first time following the collection of elasmobranch specimens from Taiwan in 2005, 2013, and 2017. This small shark was found to host 2 tapeworm species. These consist of Acanthobothrium katherineae n. sp., which is new to science and is described herein, and a second species, in the genus Scyphophyllidium, which also appears to be new, but which is represented by insufficient material for formal description. Acanthobothrium katherineae is a category 5 species. It can be distinguished from 5 of the 19 other category 5 species in that it is apolytic, retaining proglottids on its strobila until they are gravid. This new species differs from the remaining 14 category 5 species in its combination of the following features: It is a smaller worm, has fewer than 100 proglottids, has a relatively short cephalic peduncle, and differs in bothridial size and loculus ratio. Sequence data for the D1-D3 region of the 28S rDNA gene were generated for one specimen of A. katherineae. This sequence, along with comparable sequence data for adults of 14 described and 2 undescribed species as well as specimens of 6 undescribed larval members of the genus, was included in a maximum likelihood phylogenetic analysis. The resulting tree places the shark-hosted A. katherineae within a clade of stingray-hosted species, with Acanthobothrium romanowi as its sister taxon. Acanthobothrium katherineae is 1 of only 19 Acanthobothrium species known to parasitize sharks. The tree resulting from this study, which is preliminary given the relatively poor taxon sampling of the diversity in the genus, included 3 of the shark-parasitizing Acanthobothrium species and suggests that all 3 represent host-switching events. This is the first report of an Acanthobothrium species from the family Dalatiidae and the first report of a Scyphophyllidium species from the order Squaliformes. These findings suggest that other members of the Squaliformes, many of which have not previously been examined for parasites, may host additional novel cestode taxa.

Erection of Euterranova n. gen. and Neoterranova n. gen. (Nematoda, Anisakidae), with the description of E. dentiduplicata n. sp. and new records of two other anisakid nematodes from sharks off New Caledonia.

Helminthological examinations of three species of sharks, Galeocerdo cuvier, Triaenodon obesus (both Carcharhinidae, Carcharhiniformes) and Stegostoma fasciatum (Stegostomatidae, Orectolobiformes) from New Caledonian waters, carried out during 2003-2005, revealed the presence of three species of adult anisakid nematodes referable to Terranova Leiper et Atkinson, 1914. However, this genus can no longer be considered valid, because its type species has been designated a species inquirenda. Therefore, the present nematodes are assigned to two newly established genera, Euterranova n. gen. [type species E. dentiduplicata n. sp.] and Neoterranova n. gen. [type species N. scoliodontis (Baylis, 1931) n. comb.], based mainly on different labial structures. Euterranova dentiduplicata n. sp. from the stomach of S. fasciatum is mainly characterized by the presence of lips with two rows of denticles. Innominate specimens of Euterranova (a female and a third-stage larva) were collected from the digestive tract of T. obesus. Specimens of N. scoliodontis were recorded from G. cuvier. The two named species are described based on light and scanning electron microscopical examinations. Neoterranova scoliodontis has previously been recorded in New Caledonian waters from the same host species. Species previously attributed to Terranova are transferred to Euterranova (5 species), Neoterranova (4 species) or considered species inquirendae (10 species). Since Pseudoterranova Mozgovoy, 1950 was found to be a nomen nudum according to the International Code of Zoological Nomenclature (ICZN), the available name of this genus is Pseudoterranova Mozgovoy, 1953. A key to Porrocaecum-like nematode genera (Porrocaecum, Pseudoterranova, Pulchrascaris, Euterranova, and Neoterranova) is provided.

TITLE: Érection d'Euterranova n. gen. et Neoterranova n. gen. (Nematoda, Anisakidae), avec la description d'E. dentiduplicata n. sp. et de nouveaux signalements de deux autres nématodes Anisakidae de requins au large de la Nouvelle-Calédonie. ABSTRACT: L'examen helminthologique de trois espèces de requins dans les eaux néo-calédoniennes, Galeocerdo cuvier, Triaenodon obesus (tous deux Carcharhinidae, Carcharhiniformes) et Stegostoma fasciatum (Stegostomatidae, Orectolobiformes), réalisé en 2003­2005, a révélé la présence de trois espèces de nématodes Anisakidae adultes qu'on pourrait référer à Terranova Leiper et Atkinson, 1914. Cependant, ce genre ne peut plus être considéré comme valide, car son espèce type a été désignée species inquirenda. Par conséquent, les nématodes décrits ici sont attribués à deux genres nouvellement établis, Euterranova n. gen. [espèce-type E. dentiduplicata n. sp.] et Neoterranova n. gen. [espèce type N. scoliodontis (Baylis, 1931) n. comb.], principalement sur la base de différentes structures labiales. Euterranova dentiduplicata n. sp., de l'estomac de S. fasciatum, se caractérise principalement par la présence de lèvres à deux rangées de denticules. Des spécimens non nommés d'Euterranova (une femelle et une larve de troisième stade) ont été collectés dans le tube digestif de T. obesus. Des spécimens de N. scoliodontis ont été trouvés chez G. cuvier. Les deux espèces nommées sont décrites sur la base d'examens au microscope photonique et électronique à balayage. Neoterranova scoliodontis a déjà été signalé dans les eaux néo-calédoniennes chez la même espèce hôte. Les espèces précédemment attribuées à Terranova sont transférées à Euterranova (5 espèces), Neoterranova (4 espèces) ou considérées comme species inquirendae (10 espèces). Puisque Pseudoterranova Mozgovoy, 1950 s'est avéré être un nomen nudum selon le Code international de nomenclature zoologique (ICZN), le nom disponible de ce genre est Pseudoterranova Mozgovoy, 1953. Une clé des genres de nématodes de type Porrocaecum (Porrocaecum, Pseudoterranova, Pulchrascaris, Euterranova et Neoterranova) est fournie.

Septitrema lichae n. g., n. sp. (Monogenea: Monocotylidae) from the nasal tissues of the deep-sea kitefin shark, Dalatias licha (Bonnaterre) (Squaliformes: Dalatiidae), off Algeria.

Septitrema lichae n. g., n. sp. (Monogenea: Monocotylidae: Merizocotylinae) is described from the nasal tissue of the deep-sea kitefin shark, Dalatias licha (Bonnaterre) (Dalatiidae) collected off Algiers, Algeria. The new genus is distinguished from the other genera in the subfamily by the number and arrangement of the loculi on the haptor having one central and seven peripheral loculi. The diagnosis of the Merizocotylinae is amended to accommodate this species and a key to the genera of the Merizocotylinae is provided. Terminology of the haptoral loculi in the Merizocotylinae and the status of some of the genera in the subfamily are also discussed.

Neoalbionella izawai n. sp. from the smallfin gulper shark Centrophorus moluccensis Bleeker and additional host records for N. etmopteri (Yamaguti, 1939) off South Africa.

Neoalbionella Özdikmen, 2008 comprises 10 accepted species, which all infect sharks of Squaliformes and Carcharhiniformes. Adult females belonging to species of Neoalbionella, based on the maxillule palp armed with three setae and the maxilliped subchela claw with only one secondary denticle, were collected from sharks off the coast of South Africa. Neoalbionella izawai n. sp. collected from the anterodorsal part of the spiracle opening of Centrophorus moluccensis Bleeker differs from its congeners by having maxillae that are separated except at the tapering tips where they are fused and that are longer than the trunk, uropods originating from the pointed posterior margin of the trunk and that are well developed, and maxillipeds without an additional spine at the base of the subchela barb. Neoalbionella etmopteri (Yamaguti, 1939) is herein reported from two new hosts (Etmopterus spp.) off South Africa.

Intrigue surrounding the life-cycles of species of Clistobothrium (Cestoda: Phyllobothriidea) parasitising large pelagic sharks.

This study aimed to locate the adults, and thus also the definitive hosts, of three species of marine mammal-parasitising larval cestodes that have molecular affinities with Clistobothrium. New collections led to the discovery of adults of two new species of Clistobothrium, one from the longfin mako shark and one from the salmon shark. New material of Clistobothrium tumidum was collected from the great white shark and new material of a previously reported undescribed species of Clistobothrium was collected from the porbeagle shark. Larvae of Clistobothrium were opportunistically collected from sockeye salmon and four species of small squaliform sharks. Sequence data for the D1-D3 region of the 28S rDNA gene were generated for all but one of these taxa. The tree resulting from maximum likelihood analysis of those data, in combination with comparable data from GenBank, indicates that squaliform sharks can serve as intermediate hosts for the species from the porbeagle shark. The larvae from salmon exhibit a unique molecular signature and, based on diet data, may be conspecific with adults from the salmon shark. Informed by sequence data for new material of Monorygma and existing data for Phyllobothrium, the larvae provisionally identified as Monorygma grimaldii and Phyllobothrium delphini were formally transferred to Clistobothrium. Especially puzzling was that the molecular signatures of none of the eight species of Clistobothrium match those of the three marine mammal-parasitising larval forms. We are at a loss as to where else to look for the three corresponding adult forms. The great white shark remains the most likely candidate given it consumes marine mammals with some regularity, but seems unlikely to host five species of Clistobothrium. Alternatively, we are left wondering if the large marine mammal predator Carcharocles megalodon may not be extinct after all.

Spiral valve parasites of blue and common thresher sharks as indicators of shark feeding behaviour and ecology.

This study documented the parasite faunas of the spiral valves of blue sharks Prionace glauca (L. 1758) and common thresher sharks Alopias vulpinus (Bonnaterre, 1788) caught in the California Current Large Marine Ecosystem (CCLME) north of the Mexican border. The spiral valves of 18 blue and 19 thresher sharks caught in the CCLME from 2009 to 2013 were examined for parasites. Seven parasite taxa were found in blue sharks and nine in threshers. The tetraphyllidean cestode Anthobothrium sp. (78% prevalence) was the most common parasite in blue sharks, and the phyllobothriid cestode Paraorygmatobothrium sp. (90% prevalence) was the most common in threshers. An adult nematode of the genus Piscicapillaria was found in threshers for the first time and may be a new species. Adult individuals of Hysterothylacium sp. were found in both shark species. The adult acanthocephalan Rhadinorhynchus cololabis and remains of the parasitic copepod Pennella sp. - both parasites of Pacific saury, Cololabis saira - were found in the intestines of threshers, indicating recent feeding on saury. This study paves the way for a more comprehensive examination, including more samples and a wider variety of shark species, to provide a greater understanding of shark feeding behaviour and possibly provide information on shark population biology.

Description and genetic characterisation of Pulchrascaris australis n. sp. in the scalloped hammerhead shark, Sphyrna lewini (Griffin & Smith) in Australian waters.

Being listed in the IUCN Red List of Threatened Species, knowledge on the biology, health and diseases of the scalloped hammerhead, Sphyrna lewini (Griffith & Smith) is limited; this is especially true for its parasites. In this paper, a new species, Pulchrascaris australis, is morphologically described followed by genetic characterisation based on the sequence of the ITS region. The new species can be easily differentiated from its congeners based on the morphology of the mouthpart, spicules, plectanes, eggs and vulva. Phylogenetic analyses clearly distinguish specimens in the present study from other parasitic nematodes found in the Australasian waters and elsewhere. The sequencing data also suggest that Terranova larval type I found previously in various fish from New Caledonian and Australian (Queensland) waters also belong to Pulchrascaris australis n. sp.

A New Onchoproteocephalidean Cestode Species from the Spot-Tail Shark, Carcharhinus sorrah (Müller et Henle), in the Persian Gulf.

INTRODUCTION: Members of the onchoproteocephalidean genus Phoreiobothrium Linton, 1889 infect carcharhinid and sphyrnid sharks. Although the Persian Gulf harbors a rich fauna of sharks, the taxonomic diversity of Phoreiobothrium in this region has been explored little. A new species of Phoreiobothrium is herein described from Carcharhinus sorrah (Müller et Henle) off southern Iran. METHODS: Cestodes were isolated from the spiral intestine of Carcharhinus sorrah, fixed in 10% seawater-buffered formalin, and stored in 70% ethanol. For morphological examinations, worms were stained using acetic carmine; a subset was prepared for SEM. RESULTS: Phoreiobothrium sorrahcola n. sp. is the first record of the genus from C. sorrah and most closely resembles Phoreiobothrium rozatii Alijanpour Darvishi et Haseli, 2019 recently described from the Gulf of Oman. However, it differs from P. rozatii in its possession of the rectangular, rather than triangular, bothridia, a longer cephalic peduncle (878-1300 vs 466-841), the longer axial prongs of lateral and medial hooks (B 56-80 vs 43-52; B' 66-98 vs 46-62), and a greater maximum width of worm at level of scolex (302-415 vs 215-298). CONCLUSIONS: With the description of this new species, three species of Phoreiobothrium have been reported so far from the southern waters of Iran. Phoreiobothrium now includes 17 valid species infecting 16 shark species.

Insights from new cestodes of the crocodile shark, Pseudocarcharias kamoharai (Lamniformes: Pseudocarchariidae), prompt expansion of Scyphyophyllidum and formal synonymization of seven phyllobothriidean genera - at last!

Three new cestode species are described from the crocodile shark (Pseudocarcharias kamoharai) in Ecuador. All three were examined with light and scanning electron microscopy. The unique combination of morphological features in one of the new species prompted formal investigation of the non-monophyly of Paraorygmatobothrium relative to the morphologically similar genera Doliobothrium, Guidus, Marsupiobothrium, Nandocestus, Orectolobicestus, Ruhnkecestus and Scyphophyllidium. Sequence data generated for part of the 28S rDNA gene were subjected to maximum likelihood (ML) analysis. The resulting tree led to the synonymization of six of these seven genera with Scyphophyllidium, and transfer of their species to the latter genus. With the new species, the number of described members of Scyphophyllidium is now 45. The diagnosis of Scyphophyllidium is revised to accommodate these species. In addition, to expedite future descriptions, eight categories of Scyphophyllidium species are circumscribed, based largely on bothridial features. Scyphophyllidium timvickiorum n. sp. is a category 1 species. Beyond being the smallest category 1 species, it bears, rather than lacks, apical suckers and lacks, rather than bears, strobilar scutes. The two other new species are members of Clistobothrium. Clistobothrium amyae n. sp. differs from its congeners in bothridial shape, elongate cephalic peduncle and tiny size. Clistobothrium gabywalterorum n. sp. differs from the two of its congeners that also possess foliose bothridia in overall size and testis number. Despite their substantial morphological differences, the ML tree indicates they are sister taxa. Both are unique among their congeners in possessing cephalic peduncle spinitriches. The diagnosis of Clistobothrium is revised accordingly.