Juan Violante-González

A checklist of metazoan parasites of fish from Tres Palos Lagoon, Guerrero, Mexico

An extensive survey of helminth parasites in fish species from Tres Palos Lagoon, in Guerrero, Mexico, resulted in identification of 39 metazoan parasite species (37 helminth and 2 crustaceans) in 13 fish species (n = 1,498). Specimen collection in this coastal lagoon was done between April 2000 and November 2003. Digenean species (18, 8 adult and 10 metacercariae) dominated the parasite fauna. The most widespread species of parasite were: Contracaecum sp. (Nematoda), Pseudoacanthostomum panamense, Austrodiplostomumcompactum, Ascocotye (Phagicola) longa (Digenea), Neoechinorhynchusgolvani (Acanthocephala), Ergasilus sp. (Copepoda), and Argulus sp. (Branchiura). Parasite fauna species composition exhibited a clear freshwater influence as 56.4% (22 of 39) of the identified species have a freshwater distribution in Mexico. For 32 of the parasite species, this report constitutes the first geographical host record for Tres Palos Lagoon, Guerrero, Mexico.

Temporal Variation in the Helminth Parasite Communities of the Pacific Fat Sleeper, Dormitator latifrons, from Tres Palos Lagoon, Guerrero, Mexico

Temporal variation in the helminth parasite communities of the Pacific fat sleeper, Dormitator latifrons, from Tres Palos Lagoon, Guerrero, Mexico, was studied at the component community and infracommunity levels. In total, 185 host specimens were collected between April 2000 and March 2001. Eight parasite species were identified: Clinostomum complanatum, Echinochasmus leopoldinae, Ascocotyle (Phagicola) longa, Pseudoacanthostomum panamense, Saccocoelioides sp., Parvitaenia cochlearii, Neoechinorhynchus golvani, and Contracaecum sp. The communities had low numbers of parasite species and diversity, and contained only generalist parasites. Nested (nonrandom) species composition was observed in the infracommunities during all climatic seasons. The variation in nestedness intensity was attributed to a process of sequential colonization by the most common parasite species, because some were more abundant in the dry season, and others were more abundant in the rainy season.

Diplostomiasis in cultured and wild tilapia Oreochromis niloticus in Guerrero State, Mexico

This paper is a comparative study of Diplostomum (Austrodiplostomum) compactum (Lutz, 1928) in Nile tilapia Oreochromis niloticus (Linneo) from two fish farms and two nearby coastal lagoons in Guerrero state, Mexico. The higher infections levels in cultured tilapia than wild tilapia is attributed to higher fish densities in the culture systems and higher abundance of the snail Biomphalaria cf. havanensis (Pteiffer), first intermediate host of this parasite in freshwater and brackish water systems.

Parasite communities of the neotropical cormorant Phalacrocorax brasilianus (Gmelin) (Aves, Phalacrocoracidae) from two coastal lagoons in Guerrero state, Mexico

The parasite community structure of the neotropical cormorant, Phalacrocorax brasilianus, from two lagoons (Coyuca and Tres Palos) from Guerrero state, México, was examined. Fourteen species of adult helminths (6,391 individuals) from 48 cormorants were identified: 9 digeneans, 1 acanthocephalan, 1 cestode, and 3 nematodes. A total of 11 species were collected in Coyuca Lagoon and 12 in Tres Palos Lagoon. Nine species co-occurred in cormorants of both lagoons but, with the exception of Contracaecum multipapillatum and Drepanocephalus olivaceus, species were not equally common in both lagoons. The prevalence values of six species of helminth and the mean abundance of four species varied significantly between lagoons, and C. multipapillatum was numerically dominant in both lagoons. The qualitative similarity between the two communities at the component level was 64%. All cormorants examined were infected, and parasite species richness was 3–5 in Coyuca and 4–9 in Tres Palos lagoon. The results indicate that both communities presented a similar structure at the component level, probably because the cormorants of both lagoons feed on the same species of fish and thus acquire almost the same species of parasites. Differences observed at the infracommunity level were attributed to variations in the degree of dominance of the particular species.

Factors determining parasite community richness and species composition in black snook Centropomus nigrescens (Centropomidae) from coastal lagoons in Guerrero, Mexico

Species richness and composition were determined for parasite communities in the black snook Centropomus nigrescens collected from five coastal lagoons in the Guerrero state, Mexico. A total of 354 fish were collected between December 2007 and November 2008. Twenty-four species of parasite were identified: 2 monogeneans, 12 digeneans, 4 acanthocephalans, 1 cestode, 4 nematodes, and 1 pentastomid. The communities consisted mainly of autogenic parasites, and all were dominated by the digenean Paracrytogonimus yamagutii. Community species composition was similar among lagoons, although the influence of local conditions prevented them from being identical. Host traits such as predator feeding habits, body size, and vagility contributed to parasite community structure and species composition.

Metazoan parasite community of blue sea catfish, Sciades guatemalensis (Ariidae), from Tres Palos Lagoon, Guerrero, Mexico.

The seasonal dynamic of the metazoan parasite community of the blue sea catfish (Sciades guatemalensis) from Tres Palos Lagoon, Guerrero, Mexico, was studied at the component community and infracommunity levels. A total of 382 fish were collected during the regional dry and rainy seasons (a total of seven seasons) between April 2000 and September 2007. Nine helminths were collected: Neotetraonchus sp., Pseudoacanthostomum panamense, Austrodiplostomum compactum, Clinostomum complanatum, Metadena sp., Pseudoleptorhynchoides lamothei, Neoechinorhynchus cf. golvani, Hysterothylacium perezi, and Contracaecum sp. The infection dynamics of some dominant helminths was influenced by environmental changes generated by the dry/rainy season cycle. Nested (non-random) species composition was observed in the infracommunities during almost all of the sample period. Variation in the intensity of nestedness was attributed to a sequential colonization process over time by the dominant helminths.

SIX NEW AND ONE PREVIOUSLY DESCRIBED SPECIES OF PSEUDORHABDOSYNOCHUS (MONOGENOIDEA, DIPLECTANIDAE) INFECTING THE GILLS OF GROUPERS (PERCIFORMES, SERRANIDAE) FROM THE PACIFIC COASTS OF MEXICO AND PANAMA

Abstract Six new and 1 previously described species of Pseudorhabdosynochus (Diplectanidae) are described and/or reported from the gill lamellae of 5 serranid (Perciformes) fish species from the Pacific waters in Guerrero State of Mexico and Panama City, Panama. These species are Pseudorhabdosynochus guerreroensis n. sp. from the Pacific mutton hamlet Alphestes inmaculatus Breder (type host), rivulated mutton hamlet Alphestes multiguttatus (Günther), and spotted grouper Epinephelus analogus Gill from Mexico; Pseudorhabdosynochus urceolus n. sp. from the Pacific graysby Cephalopholis panamensis (Steindachner) from Taboga Island in Panama; Pseudorhabdosynochus spirani n. sp. from the starry grouper Epinephelus labriformis (Jenyns) from Mexico and the Perlas Archipelago and Taboga Island in Panama; Pseudorhabdosynochus fulgidus n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus tabogaensis n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus anulus n. sp. from E. labriformis from Mexico and Taboga Island (type locality) in Panama; and Pseudorhabdosynochus amplidiscatum (Bravo-Hollis, 1954) Kritsky and Beverley-Burton, 1986 from E. analogus and E. labriformis from Mexico and the Perlas Archipelago and Taboga Island in Panama. All new species are mainly distinguished from other species of the genus by the shape and size of the sclerotized vagina and haptoral structures. The present specimens of Alphestes, Cephalopholis, and Epinephelus spp. represent new host records and Panama represents a new geographic record for species of Pseudorhabdosynochus. The apparent common feature supporting a close similarity of these diplectanids is a single, secondary ejaculatory bulb with thickened wall.

New Species of Rhabdosynochus Mizelle and Blatz 1941 (Monogenoidea: Diplectanidae) from the Gills of Centropomid Fishes (Teleostei) Off the Pacific Coast of Mexico

In the course of the investigations into the fish parasites in the Tres Palos Lagoon in the State of Guerrero off the Pacific coast of Mexico, the following diplectanid species (Monogenoidea) from the gills of centropomids were found: Rhabdosynochus alterinstitus n. sp. from Centropomus nigrescens; Rhabdosynochus lituparvus n. sp., Rhabdosynochus volucris n. sp., and Rhabdosynochus siliquaus n. sp. from Centropomus robalito (Centropomidae). The apparent synapomorphic character supporting a sister relationship of these diplectanids is a single, sheathlike accessory piece comprising 3 distal branches of the male copulatory organ. The origin of the present diplectanid on centropomids is discussed, and it is suggested that this may be the result of allopatric speciation as a result of the uplift of the Panamanian Isthmus, thereby separating the Pacific and Atlantic Oceans during Pleistocene (3–5 million yr ago).

Helminth communities of two species of piscivorous birds, Ardea alba (Linnaeus) and Nyctanassa violacea (Gmelin) (Ciconiiformes: Ardeidae), in two coastal lagoons from Guerrero state, Mexico

The composition and species richness in helminth communities of two species of heron, Ardea alba and Nyctanassa violacea, in two coastal lagoons from Guerrero, Mexico were examined. Nineteen species of helminth (7,804 individuals) were identified in 43 adult birds: 15 digeneans, 1 acanthocephalan, 1 cestode, and 2 nematodes. Eight species co-occurred in herons of both species and lagoons. The prevalence values of seven species and the mean abundance of five species varied significantly between species of birds and between lagoons. The heterophyid, Ascocotyle (Phagicola) longa, was the helminth numerically dominant in the helminth community of A. alba in both lagoons, while the cestode, Parvitaenia cochlearii, dominated the community of N. violacea. At the component community level, species richness varied significantly: 10 species in A. alba from Coyuca to 16 in N. violacea (Tres Palos). All of the birds examined were infected with helminth parasites: three to seven species per host in A. alba from Coyuca, and two to eight species in A. alba and N. violacea from Tres Palos. The results indicate that even though species composition was similar between both species of heron, the structure of their communities was not the same. Differences in the feeding behavior of the birds (day/night habits), as well as local differences in the abundance of species of fish, and infection levels of helminths in each lagoon are suggested as being responsible for the variations registered in the structure of the helminth communities.

Interoceanic occurrence of species of Aristocleidus Mueller, 1936 (Monogenoidea: Dactylogyridae) parasitizing the gills of gerreid fishes in the Neotropics.

During investigations of fish parasites in the Neotropics (including the state of Veracruz and the Yucatán Peninsula in the Gulf of Mexico, the Chautengo Lagoon on the Pacific coast of the state of Guerrero in Mexico, and Lake Gatun in the Panama Canal), three monogenoidean (Dactylogyridae) species were found parasitizing the gills of gerreids (Gerreidae): Aristocleidus hastatus Mueller, 1936, was recovered from Eugerres plumieri (Cuvier) and Diapterus auratus Ranzani in Veracruz, from D. auratus and Diapterus rhombeus (Cuvier) in Yucatán, from Eugerres brasilianus (Cuvier) in Panama (all new hosts and geographical records), and from D. peruvianus (Cuvier) and Gerres cinereus (Walbaum) in Guerrero; Aristocleidus lamothei Kritsky and Mendoza-Franco, 2008, was recovered from E. plumieri in Veracruz and from D. rhombeus in Yucatan (new hosts and geographical records), and Aristocleidus sp. was recovered from G. cinereus in Guerrero. Results from this study suggest that species of Aristocleidus exhibit wide host specificity within gerreid fishes and that geminate species within this parasite genus may have originated with the formation of the Isthmus of Panama (3.1 to 3.5 ma). Evidence is also presented suggesting the potential role of the Panama Canal as a passageway allowing the interoceanic dispersal of Aristocleidus species across the isthmus.