Search results for "CORYNOSOMA"
showing 10 items of 13 documents
Presence of genital spines in a male Corynosoma cetaceum Johnston and Best, 1942 (Acanthocephala).
2002
We collected 83 females and 80 males of Corynosoma cetaceum from 2 common dolphins, Delphinus delphis, collected in northern Patagonia (Argentina). Worms were most similar to specimens collected in other South American localities. However, 1 male had 2 spines adjacent to the genital pore and isolated from the rest of body spines. This finding confirms the recent reassignment of C. cetaceum to Corynosoma. Absence of genital spines is suggested to be avoided as the sole criterion to exclude specimens from Corynosoma or Andracantha.
Corynosoma cetaceum in the stomach of Franciscanas, pontoporia blainvillei (Cetacea): an exceptional case of habitat selection by an Acanthocephalan
2001
Adult acanthocephalans are typically found in the intestine of vertebrates, where they can readily absorb nutrients. However, Corynosoma cetaceum has been frequently reported in the stomach of cetaceans from the Southern Hemisphere. The ecological significance of this habitat was investigated by examining data on number, sex ratio, maturity status, biomass, and fecundity of C. cetaceum in different parts of the digestive tract of 44 franciscanas Pontoporia blainvillei. Individual C. cetaceum occurred in the pyloric stomach (PS) and, to lesser degrees, in the duodenal ampulla (DA) and the main stomach (MS). Females outnumbered males in all chambers, although the sex ratio was closer to 1:1 i…
Host‐parasite relationships between two seal populations and two species of Corynosoma (Acanthocephala) in Finland
1988
Ringed seals (Phoea hispida botnica), from the Bothnian Bay, north-eastern Baltic Sea were examined for acanthocephalan parasites in 1977-1982, and specimens from Lake Saimaa in south-eastern Finland (P. h. saimensis) were examined in 1980-1981. The two seal stocks have been isolated from Arctic stock for 11,000 years and from each other for 8,000 years. Corynosoma strumosum and C. semerme were found in the Baltic seals, but only C. strumosurn in those from the lake. Eighty two of the ringed seals caught in the Bothruan Bay were infected with both Corynosoma species, one with a single infection of C. strumosum and one with C. semerme inautumn. The total number of C. semerme increased in rel…
Status of Corynosoma (Acanthocephala: Polymorphidae) based on anatomical, ecological, and phylogenetic evidence, with the erection of Pseudocorynosom…
2006
The possession of genital spines has been considered as a key taxonomic trait to differentiate Corynosoma from other genera of the Polymorphidae. However, Corynosoma currently consists of 2 groups of species with clear ecological and morphological divergences: the "marine" group (with ca. 30 species) infects mammals and piscivorous birds in the marine realm, whereas the "freshwater" group (with ca. 7 species) infects waterfowl in continental waters. Species from these groups differ in shape of body and neck, trunk spination, lemnisci length and shape, testes arrangement, and number and shape of cement glands. We tested whether species from these 2 groups formed a monophyletic assemblage bas…
Morphology, performance and attachment function in Corynosoma spp. (Acanthocephala)
2018
Background: Functional inference on the attachment of acanthocephalans has generally been drawn directly from morphology. However, performance of structures is often non-intuitive and context-dependent, thus performance analysis should be included whenever possible to improve functional interpretation. In acanthocephalans, performance analysis of attachment is available only for Acanthocephalus ranae, a species that solely relies on the proboscis to attach. Here we compare body morphology and muscle arrangement in 13 species of Corynosoma, which use their spiny body as a fundamental holdfast. A basic performance analysis using live cystacanths of two representative species is also provided.…
Assessing host-parasite specificity through coprological analysis: a case study with species of Corynosoma (Acanthocephala: Polymorphidae) from marin…
2011
In this paper we report an investigation of the utility of coprological analysis as an alternative technique to study parasite specificity whenever host sampling is problematic; acanthocephalans from marine mammals were used as a model. A total of 252 scats from the South American sea lion, Otaria flavescens, and rectal faeces from 43 franciscanas, Pontoporia blainvillei, from Buenos Aires Province, were examined for acanthocephalans. Specimens of two species, i.e. Corynosoma australe and C. cetaceum, were collected from both host species. In sea lions, 78 out of 145 (37.9%) females of C. australe were gravid and the sex ratio was strongly female-biased. However, none of the 168 females of …
Constructional morphology and mode of attachment of the trunk ofCorynosoma cetaceum (Acanthocephala: Polymorphidae)
1999
Dead specimens of Corynosoma cetaceum were used to describe the trunk musculature of this species and to infer the use of the trunk as a secondary holdfast. Inferences were based on trunk muscle arrangement, changes in trunk shape, size and distribution of spines, and geometry of tegument thickness. The foretrunk of C. cetaceum is swollen and forms a spiny disk that is bent ventrally. The disk is flattened by several groups of muscles not described previously, which seem able to finely adjust the disk surface over the substratum. Disk attachment appears to be accomplished by two dorsal neck retractor muscles specialized in pulling the anchored proboscis into the foretrunk. This mechanism ha…
Acanthocephalans from Marine Fishes from Patagonia, Argentina
2019
In this study, 542 individual fish from 20 species from the Patagonian continental shelf of Argentina were examined for acanthocephalans. A total of 1,547 acanthocephalans belonging to 5 species were collected from 18 species of fish. Adult forms were represented by 2 species: Aspersentis johni (Baylis, 1929) (Heteracanthocephalidae) from longtail southern cod, Patagonotothen ramsayi (Regan) (new host record), and Breizacanthus aznari Herna´ndez-Orts, Alama-Bermejo, Crespo, Garcı´a, Raga and Montero, 2012 (Arhythmacanthidae) from raneya, Raneya brasiliensis (Kaup). Immature worms of B. aznari were also collected from the intestine of pink cusk-eel, Genypterus blacodes (Forster) (new host re…
Ovarian development of Corynosoma semerme (Acanthocephala) during experimental infections in rats.
1987
SUMMARYThe general structure and aspects of the development of the ovaries of the palaeacanthocephalan Corynosoma semerme were studied by transmission electron microscopy using worms varying in age from 18 to 90 h obtained from experimental primary infections in hydrocortisone-treated rats instead of seals, which serve as the natural definitive hosts. The observations can be interpreted to show that the immature ovaries become transformed relatively rapidly from cellular spheres to the more complex mature ovaries consisting of the supporting and oogonial syncytia and the germ-line cells. The supporting syncytium developed before the oogonial syncytium. The cytological appearance of ovaries …
Corynosoma acanthocephalans in their paratenic fish hosts in the northern Baltic Sea
2003
En 1996-1997, nous avons etudie les stages cystacanthes de trois especes de Corynosoma (Acanthocephala), C. strumosum et C. semerme, ainsi qu'une nouvelle espece C. magdaleni parasite du chabot a quatre cornes (Myoxocephalus quadricornis) dans le golfe de Bothnie. Les longueurs du tronc et du proboscis permettent de differencier les trois especes de parasites. La stabilite temporelle de l'infection par Corynosoma est etudiee en comparant nos resultats a ceux obtenus dans la meme zone geographique centrale et cotiere) en 1977-1982 (Valtonen, 1983a). Comme C. magdaleni et C. strumosum n'etaient pas differenciees a cette epoque, elles ont ete groupees sous l'appellation "C. strumosum" pour les…