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This study investigated the factors (i.e., season, locality, sampling year, total length and maturity stage of the hosts) that might influence the structure of parasite populations and communities in the clingfish Gobiesox marmoratus. The parasite community was described and analyzed using numerical descriptors, such as prevalence, intensity and species richness, between factors previously mentioned. A total of 260 clingfish were collected from 2 localities of central Chile, four seasons and during 3 year cycles (from July 2006 to July 2009). In the whole clingfish sample, 668 parasites were found, which belonged to 14 parasite taxa; 9 of them were new records in G. marmoratus. Parasite infracommunity richness ranged 0–3 species, although 1 trematode species, Helicometrina nimia, represented 80% of all parasites collected and was the most abundant and prevalent parasite species. The average of parasite abundance and intensity (± SD) was 2.5 ± 8.2 and 7.5 ± 12.7, respectively. Generalized linear model showed that parasite communities were influenced by season, locality, sampling year, and maturity stage when considering the abundance and intensity of parasites. For the parasite richness, only the locality and maturity of fish was determinant for explaining the differences. The populations and communities of the parasite variations were variable due to differences in fish body length because prevalence, abundance and intensity of parasites significantly correlated with the fish body length. Concordantly, maturity fish were longer than immature fish. Thus, clingfish from El Tabo were longest and mature, which harbored higher parasite richness than those fish from Las Cruces.
A new bucephalid species, Prosorhynchoides carvajali sp. nov. is described. This parasite was found in three marine fish, Auchenionchus microcirrhis (type-host), A. variolosus and Sicyases sanguineus (other-hosts), collected from the intertidal rocky zones of central Chile. P. carvajali sp. nov. is characterized by a pharynx in a post-equatorial position, a large cirrus sac length (half of the total worm length) and rounded caecum extending dorsally and anteriorly from pharynx. Although Prosorhynchoides carvajali sp. nov. closely resembles P. labiata; the latter has an elongated, narrow and inverted-U-shape caecum, contrasting to P. carvajali sp. nov. which has a larger rounded caecum, directed anteriorly. To our knowledge this is the first known report of Prosorhynchoides on the South American Pacific coast.
Perumytilus purpuratus is an abundant bivalve located in the intertidal rocky zone of South America that has been considered as a key species of the ecosystem. There are few studies of the host-parasite relationship of this bivalve; thus, this research aims to analyse the spatial and temporal variation in the prevalence of trematodes in P. purpuratus. Bivalves were collected from three localities (El Tabo, Las Cruces and Montemar) of central Chile (33°S, 71°W) during different seasons of 2010. The bivalves were also collected every metre, from the lowest to the highest level of the intertidal rocky zone, to determine the parasite distribution within the localities. Three species of trematodes as sporocyst stages were found: Prosorhynchoides carvajali, Proctoeces sp. and an undetermined fellodistomid species. Of the 37,692 bivalve specimens collected, 2.68% were parasitised. The undetermined fellodistomid species was the most prevalent parasite observed (1.69%). There were little detected differences in the prevalence of some trematode species between seasons. The prevalence of P. carvajali varied between localities, being most prevalent at Montemar. The distribution of trematodes along the rocky zone within the localities was variable, with P. carvajali being more prevalent in the mid-lowest level of the intertidal zone and the undetermined fellodistomid species being more prevalent in the mid-highest level. Both the abundance of definitive hosts and the environmental conditions likely result in different levels of infection by trematodes in P. purpuratus between and within the localities.
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