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At least 271 records · Page 15Linked to original sources

Genetic differentiation in populations of the cestode Bothriocephalus acheilognathi (Cestoda, Pseudophyllidea) as revealed by eight microsatellite markers.

The genetic structure of populations of the fish cestode, Bothriocephalus acheilognathi collected from Bailianhe Reservoir (BLH), Changshou (CSH) and Liangzi (LZH) Lakes was investigated by using 8 microsatellite loci. A total of 108 adult worms were genotyped at each of the 8 loci. For the 3 populations, the mean number of alleles per locus ranged from 2.38 to 5.5, and the mean expected heterozygosity ranged from 0.432 to 0.559. The average polymorphic information content (PIC) was from 0.384 to 0.492. The significant Fis values indicated non-random mating within LZH and BLH populations. On the other hand, when samples were further classified into subpopulations at the level of host fish species, no or little heterozygote deficiency was detected at most loci, showing that cross-fertilization, predominantly, but not exclusively, must have occurred within the subpopulations. Microsatellite markers also revealed an unexpected high level of genetic differentiation, as measured by R(st) and N(m) values or by delta(u)2 genetic distance among subpopulations from different hosts. Factors influencing the population genetic structure and the parasite host specificity are discussed.

Alleles↗

Genetic variation in the mitochondrial cytochrome c oxidase subunit 1 within three species of Progamotaenia (Cestoda: Anoplocephalidae) from macropodid marsupials.

Sequence variation within 3 morphologically defined species of the anoplocephalid cestode genus Progamotaenia (P. ewersi, P. macropodis and P. zschokkei) was investigated using the cytochrome c oxidase subunit 1 gene. The magnitude of genetic variation detected within each morphospecies suggests that, in each instance, several cryptic species are present. Within P. ewersi, 5 genetically distict groups of cestodes were detected, 1 shared by Macropus robustus and M. parryi in Queensland, 1 in M. agilis from Queensland, 1 in Petrogale assimilis from Queensland, 1 in Macropus fuliginosus from South Australia and 1 in Wallabia bicolor from Victoria. In P. macropodis, cestodes from M. robustus from Queensland, Western Australia and the Northern Territory, M. parryi from Queensland and M. eugenii from South Australia were genetically distinct from those in Wallabia bicolor from Queensland and Victoria and from M. fuliginosus from South Australia. P. zschokkei consisted of a number of genetically distinct groups of cestodes, 1 in Lagorchestes conspicillatus and L. hirsutus from Queensland and the Northern Territory respectively, 1 in Petrogale herberti, P. assimilis and M. dorsalis from Queensland, 1 in Onychogalea fraenata from Queensland, 1 in M. agilis from Queensland and 1 in Thylogale stigmatica and T. thetis from Queensland. In general, genetic groups within each morphospecies were host specific and occurred predominantly in a particular macropodid host clade. Comparison of genetic relationships of cestodes with the phylogeny of their hosts revealed examples of colonization (P. zschokkei in M. agilis) and of host switching (P. zschokkei in M. dorsalis).

Amino Acid Sequence↗

Morphological and molecular characterization of tetraphyllidean merocercoids (Platyhelminthes: Cestoda) of striped dolphins (Stenella coeruleoalba) from the Western Mediterranean.

Two types of tetraphyllidean merocercoids, Phyllobothrium delphini and Monorygma grimaldii, are well known from most cetaceans world-wide. The role of cetaceans in the life-cycle of these merocercoids is unclear because their specific identity is as yet unknown. The problem is compounded by poor descriptions of both merocercoids. We used light and scanning electron microscopy, and histological techniques to provide a thorough description of merocercoids collected from 11 striped dolphins, Stenella coeruleoalba, from the Spanish Mediterranean. We also described, for the first time, specimens of P. delphini with immature proglottides. Our merocercoids were morphologically similar to those described previously, except in the structure of the apical organ. Intra- and inter-sample variability in the morphology of the apical organ suggested that it degenerates during larval development. A subsample of 16 specimens of P. delphini and M. grimaldii was characterized for the D2 variable region of the large subunit ribosomal RNA gene (LSU) and compared with published tetraphyllidean cestode LSU sequences. P. delphini showed 2 unique signatures that differed from one another by a single base, whereas all sequences of M. grimaldii were identical. This suggests that each type may represent a single species, contrary to previous speculations based on morphological data. All merocercoid specimens formed a clade together with Clistobothrium montaukensis. Based on the low degree of divergence, all specimens of this clade are predicted to be congeneric.

Abdominal Cavity↗

Characterization of the mitochondrial genome of Diphyllobothrium latum (Cestoda: Pseudophyllidea) - implications for the phylogeny of eucestodes.

The complete nucleotide sequence of the mitochondrial genome was determined for the fish tapeworm Diphyllobothrium latum. This genome is 13,608 bp in length and encodes 12 protein-coding genes (but lacks the atp8), 22 transfer RNA (tRNA) and 2 ribosomal RNA (rRNA) genes, corresponding to the gene complement found thus far in other flatworm mitochondrial (mt) DNAs. The gene arrangement of this pseudophyllidean cestode is the same as the 6 cyclophyllidean cestodes characterized to date, with only minor variation in structure among these other genomes; the relative position of trnS2 and trnL1 is switched in Hymenolepis diminuta. Phylogenetic analyses of the concatenated amino acid sequences for 12 protein-coding genes of all complete cestode mtDNAs confirmed taxonomic and previous phylogenetic assessments, with D. latum being a sister taxon to the cyclophyllideans. High nodal support and phylogenetic congruence between different methods suggest that mt genomes may be of utility in resolving ordinal relationships within the cestodes. All species of Diphyllobothrium infect fish-eating vertebrates, and D. latum commonly infects humans through the ingestion of raw, poorly cooked or pickled fish. The complete mitochondrial genome provides a wealth of genetic markers which could be useful for identifying different life-cycle stages and for investigating their population genetics, ecology and epidemiology.

Animals↗

Ultrastructural investigation of the secondary excretory system in different stages of the procercoid of Triaenophorus nodulosus (Cestoda, Pseudophyllidea, Triaenophoridae).

The formation of the definitive procercoid excretory system of the pseudophyllidean cestode Triaenophorus nodulosus has been investigated. This process can be divided into 3 main stages. In the first stage, active autophagic processes lead to the formation of intracellular excretory canals. In the second stage, the process of the autolysis is enhanced and the system of intercellular lacunae functioning as an excretory system is formed. A definitive excretory system of the procercoid forms at the next stage, by means of the migration and proliferation of undifferentiated cells replacing the lacunar system.

Animals↗

Paranoplocephala maseri n. sp. (Cestoda, Anoplocephalidae), a parasite of sagebrush voles Lemmiscus curtatus (Rodentia) in the USA.

Paranoplocephala maseri n. sp. is described from Lemmiscus curtatus (Cope) in the USA. The new species is related to Paranoplocephala omphalodes (Hermann, 1783), P. caucasica (Kirschenblat, 1938), P. kirbyi Voge 1948, P. microti (Hansen, 1947) and P. macrocephala (Douthitt, 1915) sensu Genov et al. (1996). P. maseri n. sp. differs from P. omphalodes in the position of the genital pores, testes and cirrus-sac; from P. caucasica, in which there is an unarmed cirrus, in both the distribution and larger number of testes; from P. kirbyi in the distribution of the testes, the position of the genital pores and egg dimensions; from P. microti in the distribution and smaller number of testes, the smaller egg dimensions and the position of the genital pores; and from P. macrocephala in the position of genital pores and cirrus-sac.

Animals↗

Palaearctic species of the genus Confluaria Ablasov (Cestoda, Hymenolepididae): a redescription and synonymy of C. capillaris (Rudolphi, 1810).

The types of Confluaria capillaris (Rudolphi, 1810) from Podiceps auritus in (?) Germany and the types of C. capillaroides (Fuhrmann, 1906) from Podiceps dominicus in Brazil are redescribed. C. capillaroides is recognised as a junior synonym of C. capillaris (new synonymy). Data on specimens of the same species from P. cristatus and P. grisegena in Bulgaria are also presented. The previous records of the two nominal species are critically analysed in view of the present redescriptions. The host range of C. capillaris includes only grebes of the genus Podiceps, i.e. P. auritus, P. cristatus, P. grisegena, P. dominicus and P. nigricollis; the records in other hosts (Gaviiformes, Charadriiformes and Passeriformes) are considered erroneous or doubtful. The geographical range includes Europe, Central Asia and northern South America.

Animals↗

Palaearctic species of the genus Confluaria Ablasov (Cestoda, Hymenolepididae): redescriptions of C. multistriata (Rudolphi, 1810) and C. japonica (Yamaguti, 1935), and a description of Confluaria sp.

Confluaria multistriata (Rudolphi, 1810) is redescribed on the basis of specimens from Tachybaptus ruficollis from the material of Rudolphi and Dollfus and new specimens from the same host species from Bulgaria. The types of C. japonica (Yamaguti, 1935) from T. ruficollis are also redescribed and figured. A single specimen from the collection of Krabbe, described as Taenia multistriata, is re-examined and recognised as belonging to a different species of Confluaria, the status of which remains to be established. Criteria for distinguishing the three species are proposed. In view of the present results, some of the previous records of C. multistriata and C. japonica are re-evaluated. The synonymy of the genera Colymbilepis Spasskaya, 1966 and Confluaria Ablasov in Spasskaya, 1966 is confirmed.

Animals↗

Palaearctic species of the genus Confluaria Ablasov (Cestoda, Hymenolepididae): redescriptions of C. podicipina (Szymanski, 1905) and C. furcifera (Krabbe, 1869), description of C. pseudofurcifera n. sp., a key and final comments.

Redescriptions are provided of Confluaria podicipina (Szymanski, 1905) (specimens from Podiceps nigricollis and Tachybaptus ruficollis from Bulgaria) and C. furcifera (Krabbe, 1869) (syntypes from P. grisegena from Denmark and specimens from P. grisegena, P. nigricollis and T. ruficollis from Bulgaria). C. pseudofurcifera n. sp. is described from P. cristatus from Switzerland and Bulgaria. The previous records of C. furcifera from P. cristatus in Switzerland (Joyeux & Baer, 1950), Poland (Jarecka, 1958; Korpaczewska, 1960), Czech Republic (Rysavy & Sitko, 1995) and Baltic Coast (Galkin, 1986) are recognised as belonging to C. pseudofurcifera. Confluaria Ablasov in Spasskaya, 1966 is recognised as a valid genus and Dimorphocanthus Maksimova, 1989 is confirmed as its synonym. A key to the Palaearctic species of Confluaria is presented.

Animals↗

[Three new Nadejdolepis Spasskii & Sasskaya, 1954 (Cestoda: Hymenolepididae) parasites of Charadrii (Aves) from Tasmania].

Three species of Nadejdcolepis from Tasmania, Australia, are described and illustrated. N. burgessi n. sp., a parasite of Charadrius ruficapillus, is 4-6 mm long, with rostellar nitiduloid hooks 63-66 microm long, a short evaginated cirrus 13-16 microm long with a short collar of thin spines 1 microm long, a narrow and tubular sclerotinoid vagina 40-50 long and 3-4 microm in diameter with a little ampulla 3-5 microm in diameter at the proximal end, and a membranous atrial segment with smooth, short (1 microm) and compact spines which are sometimes difficult to observe. N. smithi n. sp., a parasite of 40-50 long and 3-4 microm in diameter with a little ampulla 3-5 microm in diameter at the proximal end, and a membranous atrial segment with smooth, short (1 microm) and compact spines which are sometimes difficult to observe. N. smithi n. sp., a parasite of C. ruficapillus and Arenaria interpres, is 2-3.5 mm long, with rostellar nitiduloid hooks 90-98 microm long, a short evaginated cirrus (13 x 6.5 microm) with a short collar of thin 'bristles' of decreasing length (2-3 microm) and prolonged by a short and thin stylet, a sclerotinoid and conical vagina of 20 x 6 microm, with an ovoid ampulla 6-7 x 4-9 at its slender end, and a membranous atrial segment like that of the preceding species. N. kinsellai n. sp., a parasite of C. ruficapillus is 25-40(?) mm long, with rostellar nitiduloid hooks 89-93 microm long, a fusiform genital atrium 100 x 30 microm long with a very narrow pore, and a very long narrow cirrus-sac, which is cylindrical (not fusiform), has its aporal extremity lying in the preceding proglottis and has a slender uninterrupted wall without helicoid fibres. The poral extremity of the cirrus-sac is fastened by a long transverse muscle. An evaginated cirrus was not observed. The invaginated ejaculatory canal has two successive types of spines: a subterminal short portion (20-25 microm) with thick spines, followed by a long portion (100-120 microm) with numerous thin and compact 'bristles' 5 microm long. There is a very long convoluted spermatic duct (400-500 microm). The membranous tubular vagina is long (400-450 microm), thick-walled but not muscular and convoluted anterior to the distal part of the cirrus-sac; a chitinoid chamber, copulatory segment and sphincter are absent. Nadejdolepis species parasitic in Charadrii are reviewed. None of the species previously reported presents anatomical features similar to the three new species. N. kinsellai has morphological characters which differ in detail from other species in the genus. Hymenolepis (Hymenolepis) mudderbugtenensis Deblock & Rosé, 1962 is transferred to the genus Nadejdolepis.

Animals↗

Two new species of Litobothrium Dailey, 1969 (Cestoda: Litobothriidea) from thresher sharks in the Gulf of California, Mexico, with redescriptions of two species in the genus.

As part of a survey of the metazoan parasites of elasmobranchs of the Gulf of California, Mexico, the spiral intestines of 10 pelagic thresher sharks Alopias pelagicus and one bigeye thresher shark A. superciliosus were examined for tapeworms. Eight of the A. pelagicus specimens examined were found to host Litobothrium amplifica and L. daileyi. Both tapeworm species are redescribed based on examination of this new material with light and scanning electron microscopy, and the ranges of most of the measurements for these species are expanded; scanning electron micrographs and detailed illustrations and measurements of their segment anatomy are presented for the first time. An argument is made that the identification of the original host specimens of these species was in error and that A. pelagicus is likely to be the correct original host. In addition, L. nickoli n. sp., a third species in the genus hosted by A. pelagicus, was found in three of the 10 individual hosts examined. This species differs from all six known Litobothrium species in the form of the pseudosegments of the scolex, the anterior two being essentially non-cruciform, while the latter three are distinctly cruciform. All other species possess either no non-cruciform or at most one non-cruciform segment anteriorly. The single specimen of A. superciliosus examined was found to host the new species, L. janovyi. This species differs from L. coniformis, L. gracile and L. amsichensis in its possession of four rather than three, three and five cruciform pseudosegments, respectively. It lacks the modificiations of the fourth pseudosegment seen in L. amplifica and lacks the anterior non-cruciform fifth pseudosegment found in L. daileyi. It most closely resembles L. alopias but differs among other features in its greater total length, greater number of segments and longer mature segments. SEM of the four species collected from the Gulf of California as well as material of L. amsichensis from the goblin shark Mitsukurina owstoni that hosted the type-specimens of this species show that all surfaces of the body of all five species bear a dense covering of long filiform microtriches. L. amplifica bears a single row of large spine-like structures throughout most of the posterior margins of the first and second cruciform pseudosegment only. L. daileyi possesses one to two rows of overlapping spine-like structures on the posterior margins of the first four pseudosegments with the exception of the medial projections. The fifth pseudosegment lacks these structures. L. janovyi n. sp. bears spine-like structures on the lateral margins of only the third and fourth pseudosegments. L. nickoli n. sp. bears spine-like structures throughout the posterior margins of the first and second pseudosegments, and throughout the posterior margins of the third and fourth pseudosegments with the exception of the medial projections; the fifth pseudosegment lacks these structures. L. amsichensis bears no structures that could be considered to be spine-like on any of its pseuosegments, but possesses a border of densely arranged larger microtriches on the posterior margin of all five pseudosegments. A key to the species is included.

Animals↗

Proemotobothrium n. g. (Cestoda: Trypanorhyncha), with the redescription of P. linstowi (Southwell, 1912) n. comb. and description of P. southwelli n. sp.

A new genus, Proemotobothrium (Trypanorhyncha: Otobothriidae), is erected to contain P. linstowi (Southwell, 1912) n. comb. (syn. Otobothrium magnum Southwell, 1924) and P. southwelli n. sp. The new genus is characterised by two bothridia, paired bothridial pits, an acraspedote scolex, elongate bulbs, four hooks per principal row, hooks 4 (4') being small and uncinate, a single, filiform, intercalary hook between each principal row and by the arrangement, in tandem, of the two or three extra hooks of the armature of the external surface of the tentacle, a pattern previously known only in the family Mixodigmatidae. The two species are distinguished from one another on the basis of measurements of the scolex and bulbs, the sizes of the hooks of the principal rows and by the number and size of the additional hooks in the linear arrays on the external surface of the tentacle.

Animals↗

A redescription of Pintneriella Yamaguti, 1934 (Cestoda: Trypanorhyncha and an examination of its systematic position.

Specimens of Pintneriella musculicola Yamaguti, 1934 are redescribed based on paratype material and specimens subsequently allocated to the species by its describer. The cestode species is characterised by two bothridia, a typical heteroacanthous armature with a distinctive basal swelling and basal armature, a space between hook files 1 and 1', nine hooks per principal row, no intercalary hooks and bands of hooklets or chainettes but a distinctive space on the external surface of the tentacle between hook files 9 and 9'. The strobilia is unknown. The features described indicate that Pintneriella is a valid genus within the Heteracanthoidea. Its currently known morphological features do not allow its allocation to an existing family.

Animals↗

[From some Hymenolepididae (Cestoda)of Alaskan Charadrii birds, where Nadejdolepis bealli n.sp., is a parasite of Calidris alpina].

Nadejdolepis bealli n. sp. a parasite from Calidris alpina in Alaska (USA), is described and illustrated. It is 3-4 cm long and has: rostral nitiduloid hooks 95-96 microm long, with the blade a little longer than the handle; three testes in a symmetrical triangle; a cirrus-sac 175 microm long, not crossing the median line; a cirrus borne on an unarmed basal bulb, 25 microm long when evaginated, and armed with numerous, compact and very thin spines 1 microm long; a short (25 microm) membranous and tubular vagina with neither a sclerotinoid section nor a sphincter; and a pyriform seminal receptacle. The species is differentiated from the other species of the genus with rostral hooks of comparable length by the configuration of the male and female genital ducts; they have no equivalent particularly in the shortness of the evaginated cirrus and the type of spines with which it is armed. Mention is also made of the presence of Nadejdolepis paranitidulans (Golikova, 1959) and Wardium amphitricha (Rudolphi, 1819) from the same host in Alaska.

Alaska↗

[Three Nadejdolepis Spasskii & Spasskaya, 1954 (Cestoda: Hymenolepididae) parasites of Charadrii (Aves) of Belize].

Three Nadejdolepis from Belize, Central America, represent new geographical records (1) Nadejdolepis paranitidulans (Golikova, 1959) (rostellar hooks 40-44 microm long) from Charadrius alexandrinus; (2) N. arenariae (Cabot, 1969) n. comb. (rostellar hooks 89 microm long) from Arenaria interpres; and (3) N. litoralis (Webster, 1947) (rostellar hooks 81-85 microm long) from Calidris fuscicollis (new host record). Additional descriptions, illustrations and information pertaining to these species are included. In addition, N. saguei Rysavy. 1967 is considered a synonym of N. litoralis (Webster, 1947). N. morenoi Rysavy, 1967 (rostral hooks 80 microm long) needs to be redescribed to confirm its validity. Two species of Nadejdolepis are transferred to the genus Microsomacanthus Lopez-Neyra, 1942 because their rostellar hooks are more diorchoid than nitiduloid, becoming M. cambrensis (Davies, 1939) comb. and M. alaskensis (Deblock & Rausch, 1967) n. comb.

Animals↗