Novelty and phylogenetic affinities of a new family of tapeworms (Cestoda: Rhinebothriidea) from endangered sawfish and guitarfish.

The parasites of hosts of conservation concern are often poorly known. This is the case with the iconic group of elasmobranchs known as the sawfish of the genus Pristis, all four species of which are considered as Endangered or Critically Endangered by the International Union for Conservation of Nature (IUCN, Switzerland). Examination of cestodes from three species of sawfish (Pristis pristis, Pristis clavata, and Pristis zijsron) in Australia and one of their close relatives, the also critically endangered widenose guitarfish, Glaucostegus obtusus, in India, collected over the past 25 years, yielded four new species of tapeworms which are described herein. All four belong to the previously monotypic Mixobothrium; the diagnosis of the genus is revised to accommodate the new species. Among the new taxa is a species that had been included in previous molecular phylogenies but whose identity and affinities within the order Rhinebothriidea, and thus also its familial placement, were unclear. This species exhibits the morphological features of Mixobothrium and thus its identity is, at long last, revealed. Sequence data generated for the 28S rDNA gene for three of the new species, as well as an additional new but yet undescribed species from Pristis pectinata from Florida (USA), confirms the uniqueness of this group among the rhinebothriideans. The new family Mixobothriidae is established to house these taxa. The members of this family differ from all but one of the five other families of rhinebothriideans in lacking apical suckers on their bothridia. They are also distinctive in that their bothridia are divided into three regions. The anterior and posterior regions have similar locular configurations to one another and differ from the locular configuration of the middle region. As a consequence, the bothridia are symmetrical along both their vertical and horizontal axes. We predict that a focus on species of guitarfish in the genus Glaucostegus will be the most productive approach for discovering additional diversity in this family of cestodes.

An ancient alliance: Matching evolutionary patterns of cartilaginous fishes (Elasmobranchii) and chloromyxid parasites (Myxozoa).

Myxozoa is a group of endoparasitic cnidarians covering almost 2600 species but merely 53 species, mostly from the genus Chloromyxum, have been reported from sharks, rays, and skates (Elasmobranchii). Elasmobranchs play a key role in the study of evolutionary trajectories of myxozoans as they represent ancestral vertebrate hosts. Our study provides new data on Chloromyxum spp. from 57 elasmobranchs, covering 20 species from geographical regions and host groups not previously investigated, such as Lamniformes and Hexanchiformes, the most basal phylogenetic shark lineage. In total, 28% of elasmobranchs were infected with Chloromyxum spp., indicating high diversity. Of the seven distinguished species, six are formally described based on morphological, morphometric, and genetic (18S rDNA) data. Comprehensive co-phylogenetic analyses and ancestral state reconstruction revealed that parasite and host phylogenies are clearly correlated, resulting in a distinct phylogenetic separation of chloromyxids from selachid (shark) vs. batoid (ray and skate) hosts. Species infecting the most ancient elasmobranchs formed a sublineage, branching off in the middle of the Chloromyxum sensu stricto clade. Our findings indicate that chloromyxids likely invaded an ancestral elasmobranch prior the time of divergence of shark and batoid lineages. Our analyses did not show a clear phylogeographic pattern of Chloromyxum parasites, probably due to the cosmopolitan distribution and migratory behaviour of many elasmobranch hosts, but geographical sampling must be extended to confirm or refute this observation. This study provides a complex view on species diversity, phylogeny, evolution, host-parasite co-phylogeny, and the phylogeographic origin of Chloromyxum species from elasmobranchs. Our results highlight the importance of adding missing data from previously un- or undersampled geographical regions and host species which results in a more accurate estimate of myxozoan biodiversity and a better understanding of the evolution of this parasite group in their hosts and in the different oceans of our planet.

Sea lice (Copepoda: Caligidae) from South Africa, with descriptions of two new species of Caligus.

Thirteen species of sea lice (family Caligidae) are reported from a range of elasmobranch and actinopterygian fishes caught off South Africa or obtained from public aquaria in South Africa. Two new species of Caligus Müller, 1785 are described: C. linearis n. sp. from Pomatomus saltatrix (Linnaeus) and C. tumulus n. sp. from Chrysoblephus cristiceps (Valenciennes). A supplementary description is provided for both sexes of Caligus tetrodontis Barnard, 1948 taken from Amblyrhynchotes honckenii (Bloch) and previous records of this parasite from South African fishes are critically reviewed. It is concluded that Caligus material from Arothron hispidus Linnaeus was previously misidentified as C. tetrodontis and is in urgent need of re-examination. Morphological and molecular observations on Caligus furcisetifer Redkar, Rangnekar & Murti, 1949 indicate that this copepod is phenotypically and genetically identical to Lepeophtheirus natalensis Kensley & Grindley, 1973, and the latter becomes a junior subjective synonym of C. furcisetifer. We include new geographical distribution records for Caligus longipedis Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905 and Lepeophtheirus spinifer Kirtisinghe, 1937, extending into South African waters, as well as both new distribution and host records for Alebion gracilis Wilson, 1905, Caligus dakari van Beneden, 1892 and Lepeophtheirus acutus Heegaard, 1943. The molecular analysis confirmed the monophyly of the genus Caligus. The South African species of Caligus did not cluster together, but the two included South African species of Lepeophtheirus were recovered as sister taxa.

New monogeneans from the bathydemersal southern African endemic catshark, Holohalaelurus regani (Gilchrist, 1922).

The catshark genus Holohalaelurus Fowler is currently represented by five species distributed off the southern and eastern parts of the African coast. Very few parasitological records exist for any of these five species, representing a significant knowledge gap. We report the first monogenean species from the bathydemersal species Holohalaelurus regani (Gilchrist): a new species of Microbothriidae Price, 1936, Leptomicrobothrium holohalaelure n. sp. from the dorsal skin surface, and a new species of Hexabothriidae Price, 1942 representing a new genus, Scyliorhinocotyle narvaezae n. gen., n. sp., from the gill lamellae. Both monogenean records represent the first for any member of the catshark genus Holohalaelurus. Previously we focused on the identification of monogenean taxa of emerging veterinary importance for public aquaria. We now begin a focused effort to document a generally unexplored monogenean biodiversity from diverse marine habitats off South Africa.

A redescription of the female of Lernaeopoda bivia Leigh-Sharpe, 1930 (Lernaeopodidae: Siphonostomatoida) and a first description of the male.

Within the family Lernaeopodidae Milne Edwards, 1840 the females of Lernaeopoda spp. are very similar to those of Neoalbionella spp. Contrarily, the male morphology is different enough to allow distinction between species of the two genera. Unfortunately, males are not always attached to collected females and therefore often not described. Hence the validity of some of the Lernaeopoda spp. are still questionable due to incomplete descriptions of the female and no description of the male. Lernaeopoda bivia Leigh-Sharpe, 1930 is an example of an accepted species due to a redescription of the female done in 1986 but without a description of the male. Lernaeopoda bivia has only been reported twice, collected from Schroederichthys bivius (Müller & Henle). Recently, females with attached males were collected from Triakis semifaciata Girard from Inner Cabrillo Beach in southern California. The female morphology of L. bivia is similar to the previous redescription with some additional features and illustrations while the male conforms to the morphology of males of Lernaeopoda spp. The dental formula of males and females of the species of the genus differ with males having one P1, S1 less than females. The structure and armature of the appendages of the three described species of males (L. galei Krøyer, 1837, L. bidiscalis Kane, 1892 and L. bivia) is mostly similar with the tympanal membrane of the three species the most distinctive feature. A key to identify the females of the valid species of Lernaeopoda is provided.

Acanthocephalans from Australian elasmobranchs (Chondrichthyes) with a description of a new species in the genus Gorgorhynchus Chandler, 1934 (Rhadinorhynchidae).

Gorgorhynchus occultus n. sp. is described from Sutorectus tentaculatus (Peters) (Orectolobidae) collected off Bunbury, Western Australia in 1986. The new species differs from all other species of Gorgorhynchus Chandler, 1934 by having a suite of characters including a proboscis hook formula of 18-20 rows of 8-9 hooks, a well-developed neck, irregular circles of small spines in a single anterior field, the male reproductive system limited to the posterior quarter of the trunk and three cement glands. In a survey of 284 sharks collected between 2015 and 2018 from 10 localities in Australian waters, 11 individuals were infected with acanthocephalan cystacanths. One individual of Sphyrna mokarran (Rupell) (Sphyrnidae) was infected with Corynosoma cetaceum Johnston & Best, 1931. Serrasentis sagittifer (Linton, 1889) (Rhadinorhynchidae) was found in five individuals of S. mokarran, four individuals of Syphyrna lewini (Griffith & Smith) and one individual of Carcharhinus coatesi (Whitley) (Carcharhinidae). These infections may be accidental because it has been suggested that acanthocephalans cannot tolerate the high levels of urea used by marine and esturine elasmobranchs for osmoregulation. The two most common host species examined, S. mokarran and S. lewini had the highest intensities and prevalences of infection with S. sagittifer. Although more individuals of S. lewini were examined, S. mokarran had the higher prevalence of infection.

A new species of Branchellion Savigny, 1822 (Hirudinida: Piscicolidae), a marine leech parasitic on the giant electric ray Narcine entemedor Jordan & Starks (Batoidea: Narcinidae) off Oaxaca, Mexico.

Branchellion spindolaorum n. sp. (Hirudinida: Piscicolidae) is described based on specimens found parasitising the giant electric ray Narcine entemedor Jordan & Starks off the coast of Oaxaca, Mexico. The new species can be clearly distinguished from the other species of Branchellion Savigny, 1822 by the presence of 30 pairs of lateral branchiae and 10 pairs of pulsatile vesicles. The definition of the genus Branchellion is expanded to include species with either 30, 31 or 33 pairs of foliaceous (plate-like) lateral branchiae in the urosome. In addition, we provide for the first time for the genus, scanning electron micrographs of the secondary suckers located on the ventral surface of the posterior sucker. Additionally, partial DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) were generated and compared with homologous sequences of other species of the genus. Branchellion spindolaorum n. sp. represents the fourth species of the genus known in the Eastern Pacific and the first record of a leech parasitising N. entemedor.

A new species of Dollfusiella Campbell & Beveridge, 1994 (Cestoda: Eutetrarhynchidae), with remarks on Halysiorhynchus macrocephalus (Shipley & Hornell, 1906) (Cestoda: Mixodigmatidae) from the bowmouth guitarfish Rhina ancylostoma Bloch & Schneider (Rhinidae) in the Persian Gulf.

Dollfusiella nimai n. sp. (Cestoda: Eutetrarhynchidae) is described from the intestine of Rhina ancylostoma Bloch & Schneider in the Persian Gulf. The number of the hooks per half spiral row in the metabasal tentacular armature distinguishes the new species from its congeners, except for D. vooremi (São Clemente & Gomes, 1989) possessing approximately the same number of hooks per half spiral row. While the principle hooks 1(1')-21(21') were homeomorphous in the metabasal armature of D. nimai n. sp., the billhooks on the antibothrial surface and the uncinate hooks on the bothrial surface were the principle hooks 1(1')-16(16') in the metabasal armature of D. vooremi. Dollfusiella nimai n. sp. most closely resembles D. michiae (Southwell, 1929) in the tentacular armature as well as the morphology of the scolex and strobila but differs clearly in the number of the hooks per half spiral row in the metabasal tentacular armature (25-26 vs 16 respectively). A detailed examination of the specimens of Halysiorhynchus macrocephalus (Shipley & Hornell, 1906) (Cestoda: Mixodigmatidae) ex R. ancylostoma from the Persian Gulf revealed intraspecific variability including the number of the principle hooks per half spiral row in the metabasal armature, the number of the hook rows in the basal armature, and the size of the basal hooks.

Parasites of cartilaginous fishes (Chondrichthyes) in South Africa - a neglected field of marine science.

Southern Africa is considered one of the world's 'hotspots' for the diversity of cartilaginous fishes (Chondrichthyes), with currently 204 reported species. Although numerous literature records and treatises on chondrichthyan fishes are available, a paucity of information exists on the biodiversity of their parasites. Chondrichthyan fishes are parasitised by several groups of protozoan and metazoan organisms that live either permanently or temporarily on and within their hosts. Reports of parasites infecting elasmobranchs and holocephalans in South Africa are sparse and information on most parasitic groups is fragmentary or entirely lacking. Parasitic copepods constitute the best-studied group with currently 70 described species (excluding undescribed species or nomina nuda) from chondrichthyans. Given the large number of chondrichthyan species present in southern Africa, it is expected that only a mere fraction of the parasite diversity has been discovered to date and numerous species await discovery and description. This review summarises information on all groups of parasites of chondrichthyan hosts and demonstrates the current knowledge of chondrichthyan parasites in South Africa. Checklists are provided displaying the host-parasite and parasite-host data known to date.

Tetraphyllidean and onchoproteocephalidean cestodes of elasmobranchs from Moreton Bay, Australia: description of two new species and new records for seven described species.

Parasitological examination of elasmobranchs of Moreton Bay, Queensland, Australia, resulted in the discovery of cestodes belonging to several armed genera of the Tetraphyllidea and Onchoproteocephalidea. Two new tetraphyllideans, Yorkeria moretonensis n. sp. and Yorkeria williamsi n. sp., are described from Chiloscyllium cf. punctatum (Hemiscylliidae). Yorkeria moretonensis n. sp. differs from its congeners in the possession of vitelline follicles that are discontinuous in the region of the ovary and in the length of its pedicels. Yorkeria williamsi n. sp. is most similar to Y. parva Southwell, 1927, but has larger, oval bothridia, longer pedicels and differences in the sizes of the scolex hooks. Yorkeria longstaffae Caira, Jensen & Rajan, 2007 is reported from Moreton Bay for the first time, and Spiniloculus mavensis Southwell, 1925 is re-reported from the type-locality and likely type-host (Moreton Bay and Chiloscyllium cf. punctatum, respectively), over 90 years after its original description. Six known onchoproteocephalideans, Acanthobothrium cannoni Campbell & Beveridge, 2002, A. chisholmae Campbell & Beveridge, 2002, A. ocallaghani Campbell & Beveridge, 2002, A. margieae Fyler, 2011, Megalonchos shawae Caira, Reyda & Mega, 2007 and M. sumansinghai Caira, Reyda & Mega, 2007, are reported from Moreton Bay for the first time, representing significant range extensions for all species.

Resurrection of Alebion difficile (van Beneden, 1892) (Copepoda: Siphonostomatoida: Caligidae) with notes on other species of Alebion Krøyer, 1863 collected from elasmobranchs off South Africa and an updated key of the adult females.

Alebion Krøyer, 1863 is one of the genera of the Caligidae Burmeister, 1835 and can easily be distinguished from other genera by the presence of modified exopodal spines on legs 1-3. Currently there are eight recognised species infecting a variety of elasmobranch hosts. Alebion difficile (van Beneden, 1892) is resurrected based on the difference in the structure of the spermatophores on the genital complex of the female but also the difference in the relative lengths of the posterior processes of the genital complex, the lateral processes on the first abdominal somite and the caudal rami. Additionally, the adult male of A. difficile is described and illustrated and notes provided about the morphology of the sub-adult females and males. Other Alebion species and their hosts collected off South Africa are reported and an updated key to the adult females of the species of Alebion is provided.

The discovery of Lepeophtheirus acutus Heegaard, 1943 (Copepoda: Caligidae) from two new elasmobranch hosts in the Mediterranean Sea, and a comparative redescription of Lepeophtheirus rhinobati Luque, Chaves et Cezar, 1998.

In this study, supplementary information on the morphology of the siphonostomatoid copepod Lepeophtheirus acutus Heller, 1865 is given based on new material collected from the ventral body surface and mouth cavity of common guitarfish, Rhinobatos rhinobatos (Linnaeus) and from the branchial cavity of bull ray, Aetomylaeus bovinus (Geoffroy Saint-Hilaire) caught in Iskenderun Bay, Turkey. This is the first report of L. acutus from Mediterranean waters. Key diagnostic characters of both sexes are reported, supported by light and scanning electron microscopy observations. In addition, Lepeophtheirus rhinobati Luque, Chaves et Cezar, 1998, which is closely related to L. acutus and has been reported from the same host genus, Rhinobatos, is reexamined based on paratypes stored in the collections of the United States National Museum of Natural History. Some of the key diagnostic characters which were incompletely known or lacking in the original description of both sexes of L. rhinobati are redescribed and/or presented for the first time.

Hyperapolytic species of Acanthobothrium (Cestoda: Onchoproteocephalidea) from batoids off Argentina.

Two hyperapolytic species of Acanthobothrium Blanchard, 1848 have been collected from Discopyge tschudii Heckel, 1846 and Zapteryx brevirostris (Müller et Henle) along the coast of Argentina. Acanthobothrium stefaniae sp. n. from D. tschudii is a category one species (i.e., it is less than 15 mm in total length, possesses fewer than 50 proglottids, fewer than 80 testes and essentially symmetrical ovary), and differs from all congeners by the following combination of features: proglottid hyperapolysis, hook morphology, size and shape of the cirrus sac, and by having spinitriches in the distal bothridial surface. This is the first record of Acanthobothrium in Discopyge Heckel, 1846. The specimens from Z. brevirostris conform to the morphology of Acanthobothrium zapterycum Ostrowski de Núñez, 1971. A redescription of this species is presented, which expands most ranges of measurements originally given, and provides details omitted in the original description, including the microthrix pattern. This study allowed us to observe the intraspecific variation in ovarian symmetry in A. zapterycum, which shed some doubt on the validity of this as a diagnostic feature. The reproductive strategy (apolysis) of several species of Acanthobothrium was reviewed and summarized.

Phylogenetic evidence for an ancestral coevolution between a major clade of coccidian parasites and elasmobranch hosts.

Cartilaginous fishes are the oldest jawed vertebrates and are also reported to be the hosts of some of the most basal lineages of Cestoda and Aporocotylidae (Digenea) parasites. Recently a phylogenetic analysis of the coccidia (Apicomplexa) infecting marine vertebrates revealed that the lesser spotted dogfish harbours parasite lineages basal to Eimeria Schneider, 1875 and the group formed by Schellackia Reichenow, 1919, Lankesterella Ames, 1923, Caryospora Leger, 1904 and Isospora Schneider, 1881. In the present study we have found additional lineages of coccidian parasites infecting the cownose ray Rhinoptera bonasus Mitchill and the blue shark Prionace glauca Linnaeus. These lineages were also found as basal to species from the genera Lankesterella, Schellackia, Caryospora and Isospora infecting higher vertebrates. These results confirm previous phylogenetic assessments and suggest that these parasitic lineages first evolved in basal vertebrate hosts (i.e. Chondrichthyes), and that the more derived lineages infect higher vertebrates (e.g. birds and mammals) conforming to the evolution of their hosts. We hypothesise that elasmobranchs might host further ancestral parasite lineages harbouring unknown links of parasite evolution.

A New Genus of Tapeworm (Cestoda: Onchoproteocephalidea) from Sawfish (Elasmobranchii: Pristidae).

Collections from the dwarf sawfish, Pristis clavata, near Darwin, Australia, in 1997 led to the discovery of the new onchoproteocephalidean genus Matticestus n. gen.-a taxon that has been referred to in molecular phylogenetic analyses in which it has been included as "New genus 8." Its type species, Matticestus anneae n. gen., n. sp., and a second species, Matticestus kathleenae n. sp., are described. Placement of this taxon in the Onchoproteocephalidea is supported morphologically in that both species bear a scolex with 4 bothridia each with a pair of bi-pronged hooks and spinitriches that extend throughout the length of the body. Sequence data for the D1-D3 region of the 28S rDNA gene also place the genus solidly among the other elasmobranch-hosted members of the order. The new genus differs from the other elasmobranch-hosted genera in the order in that its members possess a combination of biloculated bothridia with lateral lappets on the posterior margin of the anterior loculus and a pair of bi-pronged hooks with a distinctive configuration of tubercles and internal channels. Its members are also extremely small. In summary, Matticestus n. gen. is an unusually tiny, "spiny," genus of cestode that seems to exclusively parasitize sawfish of the genus Pristis.

Description of four new species and a revision of the genus Tripaphylus Richiardi in Anonymous, 1878 (Copepoda: Siphonostomatoida: Sphyriidae).

Tripaphylus Richiardi in Anonymous, 1878 is one of the genera of the Sphyriidae Wilson, 1919 and it currently accommodates ten species. Only scanty descriptions are available for the females and some males of the species. Tripaphylus specimens, described and illustrated in this paper, were collected from elasmobranch hosts off the South African coast or came from the private collection of the late Dr G. Benz. Collected specimens were fixed and preserved in 70% ethanol, examined by light - and scanning electron microscopy, and compared with the known species. Descriptions and illustrations are provided for the transformed adult females and males of T. elongatus (Wilson, 1932) and T. versicolor (Wilson, 1919) while illustrated descriptions of the transformed adult females are also provided for T. ferox (Wilson, 1919) and T. vaissierei (Delamare Deboutteville & Nuñes-Ruivo, 1954). Additionally, the material previously reported as T. ferox is considered to represent T. elongatus and that reported as T. lobatus (Kirtisinghe, 1964) is considered a junior synonym of T. vaissierei. Based on the collected material the transformed adult female and male of T. lewisi n. sp. are described as well as the adult transformed females of T. benzi n. sp., T. hoi n. sp., and T. beatricae n. sp. A summarised review of the main features is provided for each of the previously described T. musteli (van Beneden, 1851), T. hemigalei Kirtisinghe, 1964, T. australis (Kabata, 1993), T. triakis (Castro Romero, 2001) and T. asymboli (Turner, Kyne & Bennett, 2003). Furthermore, reasons are provided for the recommendation that T. hemigalei be considered a species inquirenda. An identification key to the transformed adult females of all species of Tripaphylus is provided and the host records are also updated.

Morphological variability and molecular characterization of Mawsonascaris australis (Johnston & Mawson, 1943) (Nematoda: Ascaridoidea: Acanthocheilidae) from the brown guitarfish Rhinobatos schlegelii Müller & Henle (Rhinopristiformes: Rhinobatidae).

A rare ascaridoid species, Mawsonascaris australis (Johnston & Mawson, 1943), is reported from the Taiwan Strait for the first time, and the brown guitarfish Rhinobatos schlegelii Müller & Henle (Rhinopristiformes: Rhinobatidae) represents a new fish host. The detailed morphology of M. australis was studied using light and scanning electron microscopy (SEM) based on the newly collected specimens. The results revealed some important, but previously unreported or erroneous, morphological features, including the lateral alae starting well posterior to the base of the ventrolateral lips, the presence of one pair of double paracloacal papillae and a single, small precloacal median papilla on the anterior margin of the cloaca. In addition, in order to determine whether the morphometric difference in the relative lengths of the right and left spicules represents intraspecific or interspecific variation, specimens of M. australis were characterized using molecular approaches by sequencing and analysing the ribosomal internal transcribed spacer (ITS) and mitochondrial cox1 genes. The results indicate that this morphometric difference represents intraspecific variability.

Redescription of Tripaphylus musteli (van Beneden, 1851) (Copepoda: Sphyriidae) and the relegation of Paeon Wilson, 1919 to synonymy with Tripaphylus Richiardi in Anonymous, 1878.

Tripaphylus musteli (van Beneden, 1851) (Copepoda, Siphonostomatoida, Sphyriidae) is redescribed from an adult female collected from the branchial chamber of a starry smooth-hound, Mustelus asterias Cloquet (Carcharhiniformes, Triakidae), captured in the English Channel off Portland, UK. The new account of T. musteli is the first based on a complete adult female and highlighted the lack of a robust distinction separating Tripaphylus Richiardi, in Anonymous, 1878 and Paeon Wilson, 1919 prompting us to relegate Paeon to a junior subjective synonym of Tripaphylus. In the light of this synonymy the eight former species of Paeon are transferred to Tripaphylus as follows: T. ferox (Wilson, 1919) new combination, T. elongatus (Wilson, 1932) new combination, T. vassierei (Delamare Deboutteville & Nuñes-Ruivo, 1954) new combination, T. lobatus (Kirtisinghe, 1964) new combination, T. asymboli (Turner, Kyne & Bennett, 2003) new combination, T. versicolor (Wilson, 1919) new combination, T. australis (Kabata, 1993) new combination, and T. triakis (Castro Romero, 2001) new combination. Comparisons between terminology used in this report and that in the literature indicate that all transformed adult females of Tripaphylus probably possess a full complement of cephalic appendages and maxillipeds. All limbs, with the exception of the maxillae share a general morphological similarity to the corresponding appendages of conspecific males. The maxilla of the transformed adult female of Tripaphylus is a small digitiform protuberance associated with a swelling in some species.

Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae) from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus (Carcharhiniformes, Triakidae) from off Tunisia.

Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae, Merizocotylinae) is described from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus collected from the coastal marine waters off Tunisia. The new parasite species is distinguished from the other two species of the genus, T. japanicae Kearn, 1993 and T. chisholmae Justine, 2009, by the morphology of the sclerotised male copulatory organ which has longitudinal ridges. The species is also characterised by its oötype with short descending and ascending limbs (long and more convoluted in the other two species). The presence of three peripheral loculi, which is the main characteristic of the genus Triloculotrema Kearn, 1993, is unconfirmed. This is the first description of a species of this genus in the Mediterranean Sea and the first record from a coastal shark.

A new genus of rhinebothriidean cestodes from batoid elasmobranchs, with the description of five new species and two new combinations.

Survey work of batoid elasmobranchs in the eastern Atlantic and Indo-Pacific revealed multiple species of a new genus of cestode. Stillabothrium Healy et Reyda gen. n. (Rhinebothriidea: Escherbothriidae) is unique in its possession of an even number of non-medial longitudinal septa in the posterior portion of the bothridia, resulting in a series of loculi that are longer than wide (i.e. vertically oriented) and are arranged in columns. Five new species of Stillabothrium are described, S. ashleyae Willsey et Reyda sp. n., S. davidcynthiaorum Daigler et Reyda sp. n., S. campbelli Delgado, Dedrick et Reyda sp. n., S. hyphantoseptum Herzog, Bergman et Reyda sp. n., S. jeanfortiae Forti, Aprill et Reyda sp. n., and two species are formally transferred to the genus, S. amuletum (Butler, 1987) comb. n., and S. cadenati (Euzet, 1954) comb. n., the latter of which is redescribed. The species differ in the configuration of the other bothridial septa and in proglottid anatomy. Species of Stillabothrium were found parasitising a total of 17 species of batoid elasmobranchs of the genera Dasyatis Rafinesque, Glaucostegus Bonaparte, Himantura Müller et Henle, Pastinachus Rüppell, Rhinobatos Linck and Zanobatus Garman, including several host species that are likely new to science. A phylogenetic hypothesis based on Bayesian analysis of 1 084 aligned positions of the D1-D3 region of 28S rDNA for 27 specimens representing 10 species of Stillabothrium and two outgroup species supported the monophyly of Stillabothrium. These results also supported morphologically determined species boundaries in all cases in which more than one specimen of a putative species was included in the analysis. Host specificity appears to vary across species of Stillabothrium, with the number of host species parasitised by each species of Stillabothrium ranging from one to four. The geographic distribution of species of Stillabothrium spans the eastern Hemisphere, including the eastern Atlantic (coastal Senegal) and several locations in the Indo-Pacific (coastal Vietnam, Borneo and Australia). In addition, Phyllobothrium biacetabulatum Yamaguti, 1960 is formally transferred into family Escherbothriidae, although its generic placement remains uncertain (species incertae sedis).