ABSTRACT
Members of the Torpedinidae (torpedoes) and Hypnidae (coffin ray) use electric organ discharges (EOD) to stun or kill their prey before consumption. We investigated whether EOD could also negatively affect the helminth larvae infecting these preys through a surrogate model: we applied electric discharges to individuals of blue whiting, Micromesistius poutassou, that harbored live larvae of Anisakis. Larval mortality throughout a 6-h period was significantly higher in the treatment group, suggesting that EODs could significantly hamper helminth recruitment. We then tested whether torpedinids and hypnids ("strong-EOD" families) harbored species-poor helminth (cestode) assemblages compared with "weak-EOD" Torpediniformes (Narcidae and Narkidae) and other Batoidea. Based on comparisons on estimated species diversity and mean species richness of tapeworms at host individual level we found that (i) Torpediniformes had the lowest tapeworm diversity of all Batoidea orders; (ii) Torpedo spp. consistently had the lowest mean cestode richness at host individual level, and this could not be related to other host factors influencing cestode diversity in chondrichthyans, that is body size, trophic level or dietary breath. However, a preliminary comparison between "strong-EOD" and "weak-EOD" Torpediniformes did not detect clear differences of cestode richness. Thus, evidence supporting an unambiguous contribution of EODs to depauperate cestode assemblages requires further research.
Subject(s)
Electric Organ , Food Chain , Parasites , Torpedo/parasitology , Animals , Larva/parasitologyABSTRACT
A new species of parasitic copepod, Echthrogaleus spinulus n. sp. (Pandaridae), is described from the torpedo ray Tetronarce tokionis (Tanaka) (Torpedinidae) captured in pelagic Hawaiian waters. The new species has pediger 4 bearing large dorsal plates with denticles on posterior margin, genital complex with posterolateral lobes widely curved medially and overlapping, leg 4 exopod incompletely 3-segmented, and the largest body size (maximum length 16 mm from anterior rim of frontal plates to tip of caudal rami, excluding setae). This morphology does not match any of the seven valid species of Echthrogaleus Steenstrup & Lütken, 1861. Analysis of 28S rDNA sequences separated the new material from the Central Pacific from samples of E. coleoptratus in the Atlantic and Eastern Pacific Oceans. However, due to the lack of DNA sequences in the databases, the new 28S rDNA sequence cannot used to confirm the species identity. The unique morphological characteristics of the Central Pacific female copepods combined with 28S rDNA sequencing was used as a basis to validate the new species.
Subject(s)
Copepoda/classification , Torpedo/parasitology , Animals , Copepoda/anatomy & histology , Copepoda/genetics , Female , Hawaii , Pacific Ocean , RNA, Ribosomal, 28S/drug effects , RNA, Ribosomal, 28S/genetics , Species SpecificityABSTRACT
This study provides a parasitological analysis of the elasmobranch species caught in the northern and central Adriatic Sea. Sixty-two marine leeches were recorded on 747 individuals of Raja clavata Linnaeus, 1758 (thornback ray), Myliobatis aquila Linnaeus, 1758 (common eagle ray), and Torpedo marmorata Risso, 1810 (marbled torpedo ray) caught in 56 hauls over a 5 yr period. All leeches were identified as Pontobdella muricata, which is a typical ectoparasite of benthic elasmobranchs. The prevalence of infection ranged from 7.11% on R. clavata to 12.00% on M. aquila. The intensity of infection, the preferential sites of attachment to the host, and the periodicity of infection were evaluated.
Subject(s)
Ectoparasitic Infestations/veterinary , Fish Diseases/parasitology , Leeches/physiology , Skates, Fish/parasitology , Torpedo/parasitology , Animals , Ectoparasitic Infestations/epidemiology , Ectoparasitic Infestations/parasitology , Fish Diseases/epidemiology , Mediterranean Sea/epidemiology , Prevalence , SeasonsABSTRACT
Electrocotyle whittingtoni n. gen., n. sp. (Monogenea: Monocotylidae) is described from the gills of a captive female onefin electric ray, Narke capensis, collected for exhibition at Two Oceans Aquarium in Cape Town, South Africa. Electrocotyle n. gen. is most similar to the heterocotyline genera Heterocotyle and Potamotrygonocotyle but could not be accommodated easily in either of these groups. The new genus is characterised by a haptor with one central and eight peripheral loculi, four unsclerotised structures on the dorsal surface of the haptor, a single unsclerotised non-sinous ridge on the ventral surface of the haptoral septa, large hamuli with a long handle and reduced guard, a vagina with sclerotised walls, and tetrahedral eggs. Molecular phylogenetic analyses based on 28S sequences strongly support the separate genus status of Electrocotyle n. gen and thus support our morphological conclusion. The Heterocotylinae is amended to accommodate the new genus, and the new species is fully described and illustrated herein. This is the first record of a monocotylid from the Narkidae. Electrocotyle whittingtoni n. gen. n. sp. is considered potentially pathogenic given its negative impact on the health of its captive host kept in the quarantine facility at Two Oceans Aquarium.
Subject(s)
Fish Diseases/parasitology , Torpedo/parasitology , Trematoda/isolation & purification , Trematode Infections/veterinary , Animals , Female , Gills/parasitology , Oceans and Seas , Phylogeny , South Africa , Trematoda/classification , Trematode Infections/parasitologyABSTRACT
A study of the cestodes from the intestinal parasites of torpedinid elasmobranchs off the coast of Algeria, revealed the presence, in Torpedo marmorata Risso, of a species of Calyptrobothrium Monticelli, 1893, which we believe is identical to C. riggii Monticelli, 1893. This species, which has not been re-examined since its original description, is redescribed. We consider that the cestode from T. marmorata, described by Zschokke (1888) under the name of Tetrabothrium longicolle Molin, 1858, is conspecific with C.riggii. In Torpedo nobiliana Bonaparte, from the Mediterranean, we found C. occidentale Linton, 1900 and C. minus Linton, 1907. These two species are redescribed based on the type-material from the North American Atlantic coast, as well as from specimens collected off Sète and Algeria. We place several specimens, previously identified as C. riggii, as conspecific with C. minus. An amended diagnosis for Calyptrobothrium is proposed. We discuss the attribution of Bilocularia hyperapolytica Obersteiner, 1914 from Centrophorus granulosus (Centrophoridae) to Calyptrobothrium. C. chalarosomum Alexander, 1963 from Cephaloscyllium isabellum (Scylliorhinidae) off New-Zealand is excluded from the genus and placed close to Crossobothrium Linton, 1889.
Subject(s)
Cestoda/classification , Cestode Infections/veterinary , Torpedo/parasitology , Animals , Cestoda/anatomy & histology , Cestode Infections/parasitology , Fish Diseases/parasitology , Species SpecificityABSTRACT
Taeniacanthodes dojirii n. sp. (Copepoda: Poecilostomatoida: Taeniacanthidae) is described from adult female specimens collected from the body surface of Cortez electric rays Narcine entemedor (Torpediniformes, Narcinidae), captured at several locations in the Gulf of California. Taeniacanthodes dojirii is distinguished from its congeners, as well as from other members of Taeniacanthidae, by possessing unimerous fifth legs. A cladistic analysis of the 3 known species of Taeniacanthodes resulted in a single most parsimonious tree (tree length = 18 steps, consistency index = 1) demonstrating that T. gracilis and T. haakeri, both parasites of benthic teleosts, are more closely related to each other than to the new species.
Subject(s)
Crustacea/classification , Ectoparasitic Infestations/veterinary , Fish Diseases/parasitology , Phylogeny , Torpedo/parasitology , Animals , Crustacea/anatomy & histology , Crustacea/genetics , Female , Male , MexicoABSTRACT
This paper describes 2 new species of Acanthobothrium collected in Narcine entemedor from Cuajiniquil, Guanacaste Province, Costa Rica (10 degrees 57'N, 85 degrees 42'W). Acanthobothrium franus n. sp. averages 27 mm long, composed of 110 proglottides, has bothridial hooks 344-469 microns long, and 24-56 testes per proglottis. This new species resembles Acanthobothrium colombianum, Acanthobothrium coquimbensis. Acanthobothrium dujardini, Acanthobothrium lineatum, Acanthobothrium lintoni, and Acanthobothrium paulum. The new species differs from these 6 species by having a relatively shorter cirrus sac length not reaching the middle region of the proglottis. Additionally, A. franus differs from these species by having longer bothridia (627-1,408 microns vs. 299-391 microns for A. colombianum, 312-480 microns for A. coquimbensis, 240-560 microns for A. dujardini, 275-624 microns for A. lineatum, 389-720 microns for A. lintoni, and 300-880 microns for A. paulum), and larger bothridial hooks (344-469 microns vs. 175-193 microns, 120-192 microns, 180-210 microns, 118-216 microns, 108-230 microns, and 104-229 microns, respectively). Acanthobothrium inbiorium n. sp. averages 59 mm long, composed of 198 proglottides, has bothridial hooks 95-120 microns long, and possesses 44-73 testes per proglottis. Among species of Acanthobothrium, the new species resembles Acanthobothrium electricolum, Acanthobothrium dasybati, Acanthobothrium dighaensis, Acanthobothrium icelandicum, Acanthobothrium indicum, Acanthobothrium microcephalum, and Acanthobothrium wedli. The new species closely, resembles A. dasybati, but differs from that species in average strobila length and number of proglottides (58 microns long and 198 proglottides in A. inbiorium vs. 20 and 80 in A. dasybati, respectively). The new species can be distinguished from A. electricolum by having a wider scolex (450-900 microns vs. 189-252 microns), from A. dighaensis by having a narrower scolex (450-900 vs. 1,050-1,429), and from A. indicum by average strobilar length and number of proglottides (58 mm and 198 for A. inbiorium vs. 25 mm and 145 for A. indicum). Finally, A. inbiorium differs from A. icelandicum by having a shorter cirrus sac (122-285 for A. inbiorium vs. 380-410 for A. icelandicum), and A. microcephalum and A. wedli by having longer bothridia (an average of 603 microns vs. 447 microns for A. microcephalum and 350 microns for A. wedli), and fewer testes per proglottis (44-73 vs. 105-115 and 80-100, respectively). Morphological similarities suggest that some components of the eastern Pacific fauna of Acanthobothrium might share historical associations with the Caribbean and the western Pacific/Indian Ocean fauna.
