Fine structure of the female reproductive ducts of Cyathocephalus truncatus (Cestoda: Spathebothriidea), from salmonid fish

The fine structure of the ovary, ovicapt, oviduct, fertilisation canal, vitelline ducts, vitelline reservoir, ovovitelline duct, ootype and Mehlis' gland, and proximal, middle and distal parts of the uterus of the spathebothriidean cestode, Cyathocephalus truncatus (Pallas, 1781), from salmoniform fish, has been studied for the first time by transmission electron microscopy (TEM). Emphasis was given to characteristics which might shed light on the unclarified phylogenetic position of spathebothriideans, belonging among the most basal tapeworms (Eucestoda). New for cestodes is the finding of a multinucleate cell that plugs the ovicapt lumen. The morphology of the proximal part of the oviduct resembles that of the pseudophyllidean tapeworm Diphyllobothrium latum. After fertilisation in the fertilisation canal, vitellocytes of C. truncatus become associated with fertilized oocytes in the ovovitelline duct. Only one type of Mehlis' gland secretory cell is present. The eggs with electron-dense eggshells containing large pores first appear in the proximal part of the uterus. The middle portion of the uterus has well-developed uterine glands. The distal portion of the uterus has apical microtriches. Ultrastructural data on the female genital system of C. truncatus are compared and discussed with those for other cestodes. However, on the basis of available ultrastructural data it is not possible to conclude whether the Spathebothriidea are phylogenetically closer to the Caryophyllidea or to the Pseudophyllidea.     

Ultrastructure of the male reproductive system of the trematode Brachylaimus aequans

The transmission electron microscopic studies of the trematode Brachylaimus aequans revealed that the seminal vesicle and ejaculatory duct are lined with syncytial epithelium with numerous lamellate processes. The cirrus and genital pore are covered with a spineless tegument, which is almost identical with the body tegument. The testes contain tailed spermatozoa developing during spermiogenesis from biflagellate spermatids whose flagella (9 + 1) fuse with the median cytoplasmic process. The lumina of seminal vesicle, ejaculatory duct and cirrus are filled with spermatozoa.     

Wardium paucispinosum sp. n. (Eucestoda: Hymenolepididae), parasite of Larus maculipennis (Aves: Laridae) in Mar del Plata, Argentina; with comments on Wardium semiductilis (Szidat, 1964) comb. n

A new species Wardium paucispinosum (Eucestoda: Hymenolepididae) parasite from the intestine of Larus maculipennis (Lichtenstein) from Mar del Plata, Argentina is described. The distinctive features of the new species are: strobilar length 52.8 mm; 10 aploparaksoid rostellar hooks, 14 (12-17) microm long; ratio between cirrus pouch length and mature proglottid width (CPL/MPW) 0.38 (0.27-0.50); regular cylindrical evaginated cirrus, 90 x 10 microm, with distal end without spines and proximal and medium thirds covered with spines 7 microm long; simple tubular membranous vagina, 110 x 10 microm, without sclerotised portions and sphincters; eggs fusiform, 77 x 44 microm. Besides, Hymenolepis semidutctilis Szidat, 1964, from the intestine of Larus dominicanus and L. maculipennis from Santa Fe, Argentina is transferred to the genus Wardium Mayhew, 1925, based on the presence and shape of the rostellar hooks.     

Lasiotocus lizae sp. n. (Digenea: Monorchiidae), a new trematode from marine fish in the Taiwan Straits,China

Lasiotocus lizae sp. n. (Digenea: Monorchiidae) was collected from the intestine of Liza carinata (Valenciennes) (Mugilidae, Perciformes) in the Taiwan Straits, China. L. lizae is most similar to Lasiotocus glebulentus Overstreet, 1971 from the intestine of Mugil cephalus from the Northern Gulf of Mexico in having tightly compacted vitellaria, a genital pore sinistral to the midline, the ovary usually dextral to the acetabulum, the similar sucker ratio, and in the presence of both a canalicular and uterine seminal receptacle. It differs from L glebulentus in its cirrus sac ending anterior to rather than posterior to acetabulum, in the ending position of caeca, in smaller eggs, and in having a single rather than several conspicuous concretions in excretory vesicle.     

Tapeworms (Cestoda: Proteocephalidea) of firewood catfish Sorubimichthys planiceps (Siluriformes: Pimelodidae) from the Amazon River

A survey of proteocephalidean cestodes found in the firewood catfish Sorubimichthys planiceps (Spix et Agassiz) from the Amazon River is provided. The following taxa parasitic in S. planiceps are redescribed on the basis of their type specimens and material collected recently in the Amazon River, near the type localities in Brazil, and in Iquitos, Peru: Monticellia lenha Woodland, 1933; Nomimoscolex lenha (Woodland, 1933) (syn. Proteocephalus lenha Woodland, 1933); and Monticellia megacephala Woodland, 1934, for which a new genus, Lenhataenia, is proposed, with L. megacephala (Woodland, 1934) comb. n. as its type and only species. The new genus is a member of the Monticelliinae, i.e. has all genital organs in the cortex, and is most similar to Chambriella in possessing biloculate suckers and lacking a metascolex. It differs in the morphology of the cirrus-sac that contains a strongly coiled, thick-walled internal sperm duct (vas deferens) and a muscular cirrus of the appearance typical of most proteocephalideans, whereas that of Chambriella is sigmoid, with voluminous, tightly sinuous thick-walled internal sperm duct. In addition, Lenhataenia possesses a well developed internal musculature, whereas the internal musculature of Chambriella is weakly developed, formed by a low number of muscle fibres. The scolex morphology and distribution of microtriches of Peltidocotyle lenha (Woodland, 1933) (syn. Othinoscolex lenha Woodland, 1933 and Othinoscolex myzofer Woodland, 1933), Chambriella sp. and Choanoscolex sp. are described using scanning electron microscopy. The two latter taxa may be new for science and are reported from S. planiceps for the first time.     

Ultrastructure of the ovarian follicles, oviducts and oocytes of Gyrocotyle urna (Neodermata: Gyrocotylidea)

An ultrastructural study of the ovarian follicles and their associated oviducts of the cestode Gyrocotyle urna Grube et Wagener, 1852, a parasite from the spiral valve of the rabbit fish, Chimaera monstrosa L., was undertaken. Each follicle gives rise to follicular oviduct, which opens into one of the five collecting ducts, through which pass mature oocytes. These collecting ducts open into an ovarian receptacle which, in turn, opens via a muscular sphincter (the oocapt) to the main oviduct. The maturation of oocytes surrounded by the syncytial interstitial cells within the ovarian follicles of G. urna follows a pattern similar to that in Eucestoda. The ooplasm of mature oocytes contain lipid droplets (2.0 x 1.8 microm) and cortical granules (0.26 x 0.19 microm). The cytoplasm of primary and secondary oocytes contains centrioles, indicating the presence of the so-called "centriole cycle" during oocyte divisions. A morphological variation between different oviducts was observed. The luminal surface of the follicular and the collecting oviducts is smooth. The zones of the septate junctions are present within the distal portion of the net-like epithelial wall of the collecting ducts close to the ovarian receptacle. The syncytial epithelial lining of the ovarian receptacle, oocapt and main oviduct is covered with lamellae and cilia. Cortical granules secreted from mature oocytes occur freely within the lumen of the main oviduct that functions as a fertilisation canal. A division of the ovary into separated parts with their own collecting ducts as that typical of Gyrocotyle has been observed in neodermates, basal monogenean family Chimaericolidae, and Neoophora (some Proseriata and Fecampiidae). Ultrastructural data thus reveal several unique morphological characteristics of gyrocotylideans, the most basal taxon of tapeworms (Cestoda).     

Ultrastructure of the apical glandular region of the scolex of Proteocephalus torulosus (Cestoda: Proteocephalidae)

In the apical glandular region of the adult Proteocephalus torulosus (Batsch, 1786), two types of eccrine gland cells are present. The first type of unicellular gland produces large electron-dense granules of various sizes. The second type contains small electron-dense granules. Most cells form glands with large granules; glands with small granules are infrequent. The secretion of both types of gland cells is concentrated in the apical parts of the cyton and in the ducts opening to the exterior. On the scolex of P. torulosus, there are regional structural differences of the microthrix border. The apical glandular region bears filamentous microtriches only. On the remaining frontal part, surrounding the glandular region, there are blade-like and filamentous microtriches. The lateral parts of the scolex and suckers bear blade-like microtriches. Possible functions of both types of gland cells and different parts of the scolex microthrix border are discussed. The unique structure of the frontal part of the scolex of P. torulosus and its differences from Proteocephalus macrocephalus, P. longicollis and P. percae correlate well with the putative basal phylogenetic position of P. torulosus among European species of Proteocephalus.     

Potato root diffusate-induced secretion of soluble, basic proteins originating from the subventral esophageal glands of potato cyst nematodes

ABSTRACT In preparasitic second-stage juveniles (J(2)) of potato cyst nematode Globodera rostochiensis, six proteins with molecular masses of 30, 31a/b, 32, 39, and 49 kDa were recognized on Western blots by a monoclonal antibody (MGR48) specific for the subventral esophageal glands. All of these subventral gland proteins (svp's) focused in the basic range (pI 6.8 to 8.6) of an immobilized pH gradient. Western blotting showed that the svp's were present in preparasitic and parasitic J(2) and not in later juvenile stages and adult females. Minor svp quantities also were observed in adult males. Immunogold labeling of preparasitic J(2) showed that the svp's were localized in the rough endoplasmic reticulum and secretory granules of the subventral esophageal glands. Potato root diffusate triggered the secretion of svp's through the stylet, and 5-methoxy-N,N-dimethyltryptamine-hydrogen-oxalate had only a quantitative, additional effect. The forward flow of svp's through the metacorporal pump chamber was confirmed by the presence of svp's in the circular lumen of the esophagus (procorpus), as established by immunoelectron microscopy. Our data provide conclusive evidence that secretory proteins of the subventral glands of G. rostochiensis can be secreted through the stylet and support the hypothesis that the subventral esophageal glands play an important role in the early events of this nematode-plant interaction.     

Arlenelepis harpiprioni gen. et sp. n. (Cestoda: Dilepididae) from Harpiprion caerulescens (Vieillot) (Aves: Threskiornithidae) in Paraguay

Arlenelepis harpiprioni gen. et sp. n. (Cyclophyllidea, Dilepididae) is described from the plumbeous ibis Harpiprion caerulescens (Vieillot) (Ciconiiformes, Threskiomithidae) in Province Concepción, Paraguay. This cestode is characterised by a very small body (not exceeding 5 mm in length) consisting of about 30 proglottides, musculo-glandular rostellar apparatus, rostellar hooks arranged in two regular rows, few testes (7-10 in number) situated mostly in a post-ovarian group but one testis pre-ovarian, a large oval cirrus sac reaching antiporal osmoregulatory canals, massive cirrus armed with needle-shaped and thorn-shaped spines, long convoluted vagina, and longitudinally elongate sacciform horseshoe-shaped uterus with deep lobes of the medial uterine wall. The new genus is unique among the family Dilepididae in possessing a rhynchus armed with conical spines.     

Redescription of Andrya cuniculi (Blanchard, 1891) (Cestoda: Anoplocephalidae), a parasite of Oryctolagus cuniculus (Lagomorpha) in Spain

Andrya cuniculi (Blanchard, 1891) (Cestoda: Anoplocephalidae) is redescribed from Oryctolagus cuniculus (L.) from Spain. Large ranges of variability in body length and width, testes number and position of the cirrus sac were observed. An external seminal vesicle covered with small glandular cells is present. The pattern of development of the uterus is similar to that of Andrya rhopalocephala (Riehm, 1881). The only reliable differential characters to distinguish A. cunliculi from A. rhopalocephala are the position of the uterus in gravid segments and the position of the testes in mature segments. The uterus of A. cuniculi occupies the median field and parts of the lateral fields but is restricted to the median field in A. rhopalocephala. Testes are distributed more symmetrically lateral to the female organs in A. cuniculi but are mostly antiporal in A. rhopalocephala.     

Redescription of Proteocephalus bagri and p. Rhamdiae (Cestoda: Proteocephalidae), parasites of Rhamdia quelen (Siluriformes: Pimelodidae) from South America, with comments on morphological variation

The pimelodid fish Rhamdia quelen (Quoy et Gaimard, 1824) in South America harbours two species of proteocephalid cestodes, Proteocephalus bagri Holcman-Spector et Ma?é-Garzón, 1988 and P. rhamdiae Holcman-Spector et Ma?é-Garzón, 1988. These species are redescribed based on a detailed morphological study, supported by multivariate analysis (principal component analysis). Features distinguishing these species are: (1) the shape of proglottides, (2) the mean number of testes, (3) the topography of vitelline follicles, (4) the thickness of internal longitudinal musculature, (5) the mean number of uterine branches, (6) the ratio of cirrus pouch length to proglottis width, (7) the shape of ovary in mature and gravid proglottides and (8) the genital pore position in mature proglottides. The specific status of P. bagri and P. rhamdiae is confirmed and neotypes of both species are designated.     

Morphology of the uterus of Ascaris lumbricoides in the region where fertilization and formation of egg-shell occur.

Morphology of the female reproductive system of Ascaris lumbricoides L. was studied in the region starting with the junction between the oviduct and the uterus (O-U) up to the junction of both uterine branches into the vagina with regard to the process of fertilization and formation of egg-shells. In the O-U junction morphology differed in two following sections: a continuous simple squamous up to simple cuboidal epithelium, and simple cuboidal up to columnar epithelium with broad intercellular spaces leading into the lumen of the tubular reproductive organ filled with sperm. The area in the O-U junction zone was found where the wall of the organ was formed by elongated club-shaped cells attached to the common basal lamina by a narrow pedicle. Intercellular spaces thus formed "crypts" which was covered with dilated parts of cells towards the tubular lumen. Crypts were found to be filled with sperm. This area resembles the structure known as the receptaculum seminis where the stored sperm survive. Epithelial cells of the uterus are of cuboidal up to columnar shape with signs of merocrine secretion. In the distal part of the uterus the secretory active cells probably produce viscous secreta allowing the transfer of the eggs towards the vagina. The cells of the uterus wall are elongated and because of their longer axis, they are orientated longitudinally. In centripetal parts, the cell walls do not have contact with each other and form elongated, deep furrows ("canyons") through which the sperm can run against the flow of uterus content up to the junction of the O-U, where they are stored in the spermatheca-like structure. At any time they are disposal for fertilization.     

Descriptions of two new freshwater neotropical species of Rhinebothrium (Cestoda: Rhinebothriidea) from Potamotrygon motoro (Chondrichthyes: Potamotrygonidae)

Two new species of Rhinebothrium (Cestoda, Rhinebothriidea) from potamotrygonid stingrays in the Neotropical region are herein described, which raises the total number of Rhinebothrium species known from Neotropical freshwaters to five. Rhinebothrium corbatai sp. n., and Rhinebothrium mistyae sp. n. were both collected from Potamotrygon motoro (Müller et Henle), captured in four tributaries of the Paraná River in Santa Fé Province, Argentina. The new species can be distinguished from their congeners, and from each other, by a combination of various features, including worm size (length and number of proglottids), number of loculi per bothridium, microthrix pattern, size of the cirrus sac, and the extent of the vas deferens. The discovery of these new species from P. motoro supports the pattern of high host specificity in this cestode genus, and reinforces the notion that some of the previous records of the enigmatic R. paratrygoni may correspond to new species of Rhinebothrium yet to be described.     

Histological damage by the microbial metabolite and chitin synthesis inhibitor complex nikkomycin to the silk and salivary glands of the mite Tetranychus urticae

The action of the chitin synthesis inhibitor complex nikkomycin on the silk and salivary glands of Tetranychus urticae (Acari, Tetranychidae) was examined with the electron microscope. Histological defects after nikkomycin treatment included a swelling of the cisterna of rough endoplasmic reticulum (ER). Subsequent defects were vacuolation, resulting from globular ER vesicles, and damage to the secretory grana of all the glands studied (the silk gland and the anterior and dorsal podocephalic glands). The consequences of the histological changes on the salivary secretions and the production of webs are discussed.     

枣树截形叶螨种群变动与叶片SPAD值变化规律研究

探讨了阿克苏地区枣树叶片SPAD值(叶色值)与截形叶螨种群变动之间关系,为枣树截形叶螨防治提供科学依据。于2012年7月5日到8月25日对枣树截形叶螨种群动态进行监测,同时对枣树叶片SPAD值进行测定。研究发现,枣树截形叶螨种群变动与叶片SPAD值变化呈显著负相关。当截形叶螨虫口密度为10~20头/叶时,枣树叶片SPAD值为30~40;当截形叶螨虫口密度达到20头/叶以上时,对枣树叶片叶绿素的危害最为严重,枣树叶片SPAD值为20~30。初步摸清了枣树截形叶螨种群变动与叶片SPAD值变化规律。     

Branchotenthes octohamatus sp. n. (Monogenea: Hexabothriidae) from the gills of the southern fiddler ray, Trygonorrhina fasciata (Rhinobatidae) in South Australia: description of adult and larva

Branchotenthes octohamatus sp. n. (Monogenea: Hexabothriidae) is described from the gills of the southern fiddler ray, Trygonorrhina fasciata Müller et Henle (Elasmobranchii: Rhinobatidae), off Adelaide, South Australia. It is distinguished from the type species, Branchotenthes robinoverstreeti Bullard et Dippenaar, 2003, by producing eggs that are joined end to end forming a chain, in the morphology of the male copulatory organ that has a pronounced constriction in duct diameter between proximal and distal regions, the possession of a thin muscular layer surrounding the proximal part of the male copulatory organ and distal region of the vaginae, and by the absence of a raised process on the shaft of the hamulus. An amended generic diagnosis is provided and the reliability of sperm duct number as a generic character is discussed. The oncomiracidium of B. octohamatus is also described and is the first monogenean to be described with only eight hooklets in the larval haptor. This discovery of eight hooklets may be important for higher-level monogenean evolutionary hypotheses.     

Paranaella luquei gen. et sp. n. (Monogenea: Microcotylidae), a new parasite of Brazilian catfishes

Paranaella, a new microcotyline monotypic genus, is erected to accommodate Paranaella liquei sp. n., parasite of gill filaments from Hypostomus sp., Hypostomus regani (Ihering) and Rhinelepis aspera Spix et Agassiz (Loricariidae) from the Parani River, Brazil. The new genus is most closely related to Microcotyle Van Beneden et Hesse, 1863, Diplostamenides Unnithan. 1971 and Solostamenides Unnithan, 1971. From Microcotyle it differs mainly by having the genital atrium formed by a muscular ring with a concentric row of numerous elongate and straight spines; from Diplostamenides it can be distinguished by the unarmed and not differentiated cirrus and from Solostamenides it differs by the single vaginal pore and absence of larval hooks.     

Neoskrjabinolepis merkushevae sp. n. (Cyclophyllidea: Hymenolepididae), a new cestode from shrews from the Palaearctic region

Neoskrjabinolepis (Neoskrjabinolepidoides) merkushevae sp. n. is described from the shrew Sorex minutus L. (type host) from Belarus. The new species is characterised by rostellar hooks 35-37 microm long, provided with small epiphyseal thickening of the handle; short (35-40 microm) cirrus consisting of a basal part with claw-shaped spines, a parabasal part with thin needle-shaped spines and an unarmed distal part; cirrus-sac slightly passing into median field; and 12-16 eggs per gravid uterus. In addition to the type host and the type locality, the host range of the new species includes Sorex araneus L. and there are geographical records from Bulgaria, Lithuania and North-East Altay (Russia).     

Ultrastructure of the forebody and foregut tegument and eccrine gland cells of Crepidostomum metoecus (Trematoda: Digenea: Allocreadiidae)

The forebody and foregut of Crepidostomum metoecus Braun, 1900 are invested with a tegument bearing regularly arranged surface tubercles comparable with the aspidogastrean surface structures. The tegument of the ventrolateral lobes and of the prepharynx is penetrated by ducts of eccrine gland cells. The frontal and prepharyngeal gland cells, localised in the parenchyma, discharge electron-dense granules. Their ducts are lined by peripheral microtubules and fixed to the tegument plasmalemma by a septate junction. The functional roles of these glands are discussed.