ABSTRACT 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 Hernández-Orts, Alama-Bermejo, Crespo, García, 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 record). Cystacanths of 3 species of Corynosoma Lühe, 1904 (Polymorphidae) were found encapsulated in the mesenteries of fish. Corynosoma australe Johnston, 1937 was the most abundant acanthocephalan in our study, infecting 18 species of fish and accounting for >89.9% of all specimens collected. A cystacanth of Corynosoma bullosum (Linstow, 1892) was found in “castañeta”, Nemadactylus bergi (Norman) (new host record), and cystacanths of Corynosoma cetaceum Johnston and Best, 1942 were collected from red searobin, Prionotus nudigula Ginsburg, and flounders Paralichthys isosceles Jordan (new host record) and Xystreurys rasile (Jordan). The Patagonian shelf of Argentina represents a new locality record for A. johni and C. bullosum . This survey is a starting point for understanding the diversity of marine acanthocephalans in Patagonian waters.

Empruthotrema chisholmae n. sp. is described from specimens recovered from a bull ray Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817) at the Oceanogràfic Aquarium in Valencia, Spain. The bull ray was caught in the Spanish Mediterranean (Puerto de Mazarrón, Murcia). The new species resembles 4 others of the same genus ( Empruthotrema dasyatidis Whittington and Kearn, 1992 , Empruthotrema kearni Whittington, 1990 , Empruthotrema stenophallus Chisholm and Whittington, 2005 , and Empruthotrema tasmaniensis Chisholm and Whittington, 1999 ) in having a haptor with 13 marginal loculi, the posteriormost loculus single and medial. The new species can be distinguished from these other species of the genus by the morphology of the sclerotized male copulatory organ, which is the shortest described. The new species also differs from the other species by the following combination of features: haptor with 13 marginal loculi, the presence of eyespots, the absence of an accessory piece associated with the male copulatory organ, and a long egg appendage (more than 150 µm). Empruthotrema chisholmae is the first species of the genus reported from the Mediterranean.

There is an increasing interest in parasites of marine mammals of Argentina. Here, we examined several poorly known cetaceans, i.e., 2 spectacled porpoises and 1 Burmeister's porpoise (Phocoenidae), and 1 Gray's beaked whale and 1 Cuvier's beaked whale (Ziphidae); we also updated the parasite information for 1 sperm whale (Physeteridae). These hosts strand only occasionally. We found Anisakis simplex s.l. in 2 spectacled porpoises and the Burmeister's porpoise, and recorded its distribution among the stomach chambers. Anisakis physeteris infected the sperm whale; Corynosoma cetaceum occurred in the duodenal ampulla of the Burmeister's porpoise; Corynosoma australe was found in the posterior-most region of the intestine of 1 spectacled porpoise, while another one had Tetrabothrius sp. in the anal crypts; Corynosoma bullosum and Corynosoma sp. were found in the sperm whale. The only digenean found was Pholeter gastrophilus in the Burmeister's porpoise. Merocercoids of Phyllobothrium delphini were present in the blubber of 1 spectacled porpoise, the sperm whale, and the Gray's beaked whale, while Scolex pleuronectis infected the Gray's beaked whale and 1 spectacled porpoise. No parasites were recovered from the Cuvier's beaked whale. Poor parasite-species assemblages are consistent in marine mammals of Patagonia. Given the conservation status of these hosts, the limited parasitological information gathered is valuable for conservation or management of these hosts in Patagonia.

We studied the helminths of 18 common dolphins, Delphinus delphis , from northern Patagonia. Parasites were found only in the gastrointestinal tract. Four species were in the stomach, the nematode Anisakis simplex , the acanthocephalan Corynosoma cetaceum , and the digeneans Braunina cordiformis and Pholeter gastrophilus , plus 1 digenean in the hepatopancreatic ducts, Oschmarinella rochebruni . Infection levels were low (0–155 parasites). Braunina cordiformis and C. cetaceum were the most prevalent species. Anisakis simplex was mainly concentrated in the forestomach, B. cordiformis in the main stomach, and C. cetaceum in the pyloric stomach. Component diversity was low and component evenness was intermediate. Infracommunity diversity was also low, and the mean evenness was higher than at the component community level. Low prevalence in common dolphins is consistent with parasite assemblages of other cetaceans off Patagonia. None of the parasites found is specific to this host species within the study area. We suggest that potential prey are probably important in parasite transmission in this and other dolphins from the Patagonian region.

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 based on a phylogenetic analysis by using 15 morphological characters. We also included species of Andracantha , Polymorphus , and Hexaglandula with which potential taxonomic conflicts could most likely arise. We obtained 108 equally most parsimonious trees of 32 steps, with a consistency index (CI) = 0.59, and a retention index (RI) = 0.82. The strict consensus tree indicated that the “freshwater” species of Corynosoma form a monophyletic assemblage closely related to some species of Polymorphus , whereas the “marine” species of Corynosoma are grouped together with Andracantha . Accordingly, Corynosoma is not a monophyletic assemblage, and Pseudocorynosoma n. gen. is proposed for the “freshwater” species of Corynosoma . This decision was strongly supported by (1) a functional comparison of foretrunk muscles between species of Polymophus , Andracantha , and Corynosoma ; (2) a multivariate morphometric study of proboscis characters and egg size; and (3) an analysis of ecological patterns of host–parasite relationships.

We examined the gastrointestinal helminth fauna of 2 Cuvier's beaked whales, Ziphius cavirostris , stranded on the Spanish Mediterranean coast. Information regarding intestinal parasites of this species is provided for the first time. Six helminth taxa were identified. Thirty type II larvae of the nematode Anisakis sp. were found in the stomach and the intestine of both hosts; 2 type I larvae of Anisakis sp. were found in the intestine of 1 host. One juvenile of the acanthocephalan Bolbosoma vasculosum was found in the intestine; the metacestode Scolex pleuronectis was found mainly in the terminal colon and the anal crypts of both hosts; adult cestodes of Tetrabothrius sp., which may represent a new species, were collected from the duodenum of 1 host. Composition of the intestinal parasitic community is similar to that of other oceanic cetaceans, which mostly include species of Bolbosoma and tetrabothriids (Cestoda).

The original description of the type species of Allencotyla , A. mcintoshi Price, 1962 , was based on 5 specimens collected from 1 amberjack Seriola lalandi in Florida. In this study, A. mcintoshi is redescribed based on new specimens collected from juvenile greater amberjacks S. dumerili captured off the Spanish Mediterranean coast and maintained in experimental culture tanks. Except for a slightly smaller size, individuals of S. dumerili were morphologically similar to the type specimens. However, reexamination of the type material and examination of the new specimens revealed the following discrepancies with respect to the original description: (1) the vaginal pore is unarmed and covered with pointed folds with a spinelike appearance; (2) the cirrus is armed, but spines are frequently lost (e.g., in the type specimens); (3) the esophagus is long with 3 or 4 pairs of diverticula and branches into cecae at the level of the genital atrium; and (4) the genital atrium is surrounded by 8 concentric crowns of spines, not 11 or 12 as reported in the original description. An emended diagnosis of Allencotyla is presented.