« Previous |
11 - 19 of 19
|
Next »
Number of results to display per page
Search Results
12. Morphology of Bertiella studeri (Blanchard, 1891) sensu Stunkard (1940) (Cestoda: Anoplocephalidae) of human origin and a proposal of criteria for the specific diagnosis of bertiellosis
- Creator:
- Galán-Puchades, Maria Teresa, Fuentes, Márius Vicent, and Mas-Coma, Santiago
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Bertiella studeri, diagnosis of bertiellosis, species complex, and morphology
- Language:
- English
- Description:
- Human material of an African specimen of Bertiella studeri (Blanchard, 1891 ), a typical intestinal ceslode of monkeys, is described. Mature, postmaturc and gravid proglottides, and eggs, previously inadequately figured, are illustrated and photographed. The description of the species agrees with that provided by Stunkard (1940). A comparative study with other descriptions of the species is made in an attempt to clarify previous findings. The morphological differences reported in various earlier descriptions of the species suggest that B. studeri should be regarded as a “B. studeri species complex”. Improvements are required in the descriptions of new future findings in order to clarify the specific diagnosis of human bertiellosis. Evidence suggests that a generalised diagnosis exclusively based on egg size and geographical distribution is insufficient to differentiate B. studeri and Bertiella mucronata (Meyner, 1895), or additional species may be affecting humans.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
13. Morphology, homogonic development, and lack of a free-living generation in Strongyloides robustus (Nematoda, Rhabditoidea), a parasite of North American sciurids
- Creator:
- Bartlett, C. M.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Strongyloides robustus, nematode, taxonomy, morphology, homogonic development, free-living generation, sciurids, and red squirrels
- Language:
- English
- Description:
- Adult females of Strongyloides robustus Chandler, 1942, a parasite of sciurids in North America, were found in the duodenal mucosa of 30 of 32 red squirrels (Tamiasciurus hudsonicus (Erxleben)) collected in Cape Breton Island, Nova Scotia, Canada. The parasitic female is illustrated and redescribed; characteristics include: body 3.8-8.0 mm long, cephalic extremity with X-shaped mouth and 8 circumoral lobes, ovaries spiralling around intestine, and tail bluntly rounded. Eggs in fresh feces contained tadpole-stage larvae. In fecal cultures, eggs hatched and larvae invariably developed to the filariform infective third stage; i.e. a free-living generation did not occur and is probably absent in S. robustus in Cape Breton and possibly other parts of North America. It is hypothesized that homogonically developing S. robustus might be more fecund or more efficiently transmitted than species of Strongyloides that exhibit both homogonic and heterogonic development. Larvae of S. robustus in fecal cultures, i.e. homogonic larvae, are described in detail. Intestinal walls of second- and third-stage larvae, as well as the lateral chords of young third-stage larvae, contained numerous round bodies, likely nutrient stores. Third-stage larvae were present within 2 days in cultures maintained at 30°C, 4 days at 20°C, and 7 days at 15°C. They lived for at least 33 and 30 days at 15° and 20"C, respectively. Third-stage larvae probably die when their nutrient stores are exhausted.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14. New data on the morphology and systematic status of Klossinemella iheringi (Nematoda: Atractidae) from an Amazonian serrasalmid fish
- Creator:
- Moravec, František and Thatcher, Vernon E.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Klossinemella, parasitic nematode, morphology, freshwater fish, Mylesinus, Amazon, and Brasil
- Language:
- English
- Description:
- The morphology of the nematode Klossinemella iheringi (Travassos, Artigas et Pereira, 1928), the type species of the genus Klossinemella Costa, 1961, was studied using specimens collected from the serrasalmid fish, Mylesinus paraschomhurgkii légu, Santos et Ferreira, 1989 (a new host record), from the Trombetas River, Para State, Brazil, by both light and scanning electron microscopy. This species was also recorded from the Jari River (Pará State), the Uatuma, Pitinga and Capucapu Rivers (Amazonas State), and the Araguari River (Amapá State). An examination by SEM made it possible, for the first time in this genus, to study in detail the structure of the cephalic end. Characteristic features are the presence of 8 cephalic papillae arranged in two circlets, well developed lateral amphids, and especially a crown of 8 cephalic, Y-shaped sclerotized pieces (outgrowths). The male possesses 8 pairs of caudal papillae (3 preanals, 1 adanal and 4 postanals), two unequal spicules (0.156-0.294 mm and 0.069-0.099 mm long) and a gubemaculum (0.027-0.045 mm in length); previously undescribed deirids were also found. This is the first record of this parasite from the Amazon River basin. The genus Proatractis G. Caballero, 1971 is considered a synonym of Klossinemella Costa, 1961, belonging to the cosmocercoid family Atractidae, and its type species is transferred to the latter genus as Klossinemella parvicapilico-rnnala (G. Caballero, 1971) comb. n.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
15. Nybelinia queenslandensis sp. n. (Cestoda: Trypanorhyncha) parasitic in Carcharhinus melanopterus, from Australia, with observations on the fine structure of the scolex including the rhyncheal system
- Creator:
- Jones, Malcolm K. and Beveridge, Ian
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Cestoda, Trypanorhyncha, Tenlaculariidae, Nybelinia, morphology, scolex, ultrastructure, tentacles, and taxonomy
- Language:
- English
- Description:
- A new species of Nybelinia Poche, 1926, N. queenslandensis sp. n. (Cestoda: Trypanorhyncha) is described from sharks, Carcharhinus melanopterus (Quoy et Gaimard, 1824) from the coast of northeastern Queensland, Australia. Morphological features of the 46 known species of Nybelinia Poche, 1926 are tabulated and the new species is differentiated from all known taxa that are adequately described on the basis of having a homcomorphous armature, metabasal hooks 20-25 pm long, tentacles 0.07-0.09 mm in diameter, short bulbs (0.38-0.45 mm) and craspedote segments with the testes encircling the female genital complex. The fine structure of the scolex microtriches, frontal and rhynchodeal glands, tentacles and hooks, sheath and retractor muscle is described and compared with that of other trypanorhynchs.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16. Nymphal sexual dimorphism in the sheep tick Ixodes ricinus (Acari: Ixodidae)
- Creator:
- Dusbábek, František
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Ixodes ricinus, sheep tick, nymphs, sexual dimorphism, morphology, and development
- Language:
- English
- Description:
- Unfed nymphs of Ixodes ricinus (L.) can be divided into two morphological groups according to the length of idioso-ma, scutum, hypostome and palpal segment III, and the number of dorsal alloscutal setae. Specimens of greater body dimensions and more numerous dorsal alloscutal setae moulted predominantly into females. The frequency of different nymphal length categories in field-collected ticks followed a normal distribution. The length of unfed nymphs correlates well with the length (r = 0.7248 ± 0.0711, P < 0.001) and weight (r = 0.6519 ± 0.0782, P < 0.001) of engorged nymphs, however, it varies in ticks of different origin. In field-collected ticks, freshly engorged female nymphs were 2.30-2.94 mm long, male nymphs 2.14-2.46 mm long. Feeding period (P < 0.05) and premoulting period (P < 0,001 ) were significantly longer in female nymphs both in field-collected and laboratory-derived I. ricinus. The engorgement weight was found to be the best criterion for differentiation of male and female nymphs of ixodid ticks. In field-collected nymphs engorged on BALB/c mice, 98.6 % of females moulted from nymphs weighting more than 3.60 mg, while in laboratory-derived ticks, 98.4 % of females emerged from nymphs of 3.42 mg body mass or more.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
17. On the morphological variability of the attachment organ of Lernaeopodidae (Copepoda: Siphonostomatoida)
- Creator:
- Benkirane, Ouafae, Coste, Fancoise, and Raibaut, André
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- morphology, bulla, parasitic copepods, and Lernaeopodidae
- Language:
- English
- Description:
- The study of the bulla from 18 lemaeopodid copepod species collected on 15 marine fish species and one freshwater fish species taken mainly from the Gulf of Lions in the Mediterranean Sea reveals a great morphological and structural variability. It is however possible to bring forth three general remarks: - the bulla of Lernaeopodidae parasites of Selachii have a remarkably constant structure probably due to the tegument nature of the attachment substratum; - the bulla of Lernaeopodidae parasites of Teleostei has a morphology influenced by the nature of the attachment tissue; - when species of a same genus (i.e. Clavellotis) are attached on a same organ, the shape of the bulla can constitute a taxonomic characteristic.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18. Redescription and life cycle of Gangesia par asiluri (Cestoda: Proteocephalidae), a parasite of the Far Eastern catfish Silurus asotus
- Creator:
- Shimazu, Takeshi
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Gangesia parasiluri, Cestoda, morphology, life cycle, and Japan
- Language:
- English
- Description:
- Gangesia parasiluri Yamaguti, 1934 (Cestoda: Proteocephalidae) is redescribed on the basis of adults obtained from the intestine of Silurus asotus Linnaeus (Teleostei: Siluridae) from Lake Suwa, Nagano Prefecture, central Japan. Its life cycle was studied in the field and laboratory. Rostellar hooks of the adults showed a wide variation in number, ranging from 35 to up to 57. Plerocercoids were found in the rectum of Chaenogobius urotaenia (Hilgendorf) and Rhinogobius brunneus (Temminck et Schlegel) (Teleostei: Gobiidae) from the same lake. Procercoids were formed in the haemocoel of Mesocyclops leuckarti (Claus) (Copepoda: Cyclopidae) 7 days post infection at 21-25°C. They developed into plerocercoids in the intestine of Pseudorasbora puntila pumila Miyadi (Teleostei: Cyprinidae), R. brunneus and S. asotus. Plerocercoids from naturally and experimentally infected fishes were fed to S. asotus, from which immature worms were recovered. It is considered that the life cycle involves three hosts: a copepod as the intermediate host in which procercoids are formed, small fish as paratenic hosts which retain plerocercoids and transport them into S. asotus, and S. asotus as the definitive host in which adults develop. Rostellar hooks of the adults were much fewer, much larger and arranged in fewer circles than those of the plerocercoids. It is suggested that the former are newly formed and replace the latter in an early stage of development of plerocercoids into adults in 5. asotus.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
19. Sexual dimorphism in the hair follicle mites (Acari: Demodecidae): scanning electron microscopy of Soricidex dimorphus
- Creator:
- Bukva, V.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Acari, Demodecidae, morphology, and sexual dimorphism
- Language:
- English
- Description:
- Sexually dimorphic features of adult males and females of Soricidex dimorphus, a species unparalleled in its dimorphism by any described representative of the family Demodecidae, are compared by scanning electron microscopy. The account of sexual dimorphism in S. dimorphus is preceded by a review of sexually dimorphic features in other demodecid genera. Minute constituents of general morphology of demodecid mites such as claws, solenidia and spines of legs or palps, dorsal podosomal tubercles, and integumental slits and pores, part of which are reported and/or shown in scanning electron micrographs for the first time, are also receiving detailed attention.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public