Guillermina Cabañas-Carranza

Helminth parasites in freshwater fish from the Papaloapan river basin, Mexico

A checklist based on previously published records and original data is presented for the helminth parasites reported in 35 fish species from nine families from the Río Papaloapan basin, east Mexico. The checklist contains 85 taxa from 39 helminth families. Trematodes and nematodes were the most abundant taxonomic groups. The helminth fauna in the fish of the Papaloapan River basin predominantly consists of Neotropical species that are largely autogenic. The introduced species Centrocestus formosanus was the most widely distributed helminth, infecting 16 host species. Ten of the recorded helminth species have only been found in fish from the Papaloapan. This inventory contributes 157 new host records, and reports the presence of 30 helminth species in the Papaloapan for the first time . This inventory shows the richness of helminth parasite species in the fish of the Papaloapan River basin in comparison with the other hydrological basins in Mexico. It also demonstrates that this fauna is typically Neotropical and quite similar to that from the neighboring basins of the Grijalva–Usumacinta system and the Yucatan Peninsula. The data also suggest highly effective transmission between environments within the same basin and that the regional parasite fauna is strongly influenced by fish community composition.

Helminth Parasites of Freshwater Fishes of the Pánuco River Basin, East Central Mexico

Abstract This study presents results from a survey of helminth parasites of fishes in the Pánuco River basin, in the states of San Luis Potosí, Hidalgo, Querétaro and Guanajuato, all in east central Mexico. Seventeen freshwater fish species (n = 1,019) were examined for helminths between May 1997 and September 1998. Thirty-one helminth species were collected: 11 allogenic species, mostly Nearctic in origin, and 20 autogenic species. Two anthropogenically introduced species were recorded. The most prevalent and widespread helminth taxon was Posthodiplostomum minimum (metacercariae). The helminth fauna of fishes of the Pánuco River is dominated by trematodes (12 species) and nematodes (11 species) accompanied by a few monogenean (4 species), cestode (3 species), and acanthocephalan (1 species) taxa. Most of the helminth taxa reported have been reported from other regions of Mexico. Thus, the helminth parasite fauna of fishes of the Pánuco River basin are not exclusive, including a primordially autogenic Neotropical species component mixed with a mainly allogenic, globally distributed Nearctic species component. The regional freshwater fish helminth fauna is associated with the ichthyofaunanal composition of the basin. The nematode family Rhabdochonidae displays high species richness in this hydrological basin of Mexico.

Helminth Parasites of Freshwater Fishes of the Ayuquila River, Sierra de Manantlán Biosphere Reserve, West Central Mexico

Abstract This study presents results from the first survey of the helminth parasites of fishes in the Ayuquila River, Sierra de Manantlán Biosphere Reserve, in the states of Jalisco and Colima, west central Mexico. Twenty-eight helminth species were collected from 14 freshwater fish species in July 2000 and February 2001. No helminth species collected is exclusive to the Ayuquila River: 11 are allogenic species, mostly Nearctic in origin, and 17 are autogenics. Three introduced species were recovered. Saccocoelioides sogandaresi (Trematoda) was the most prevalent and widespread helminth recovered. The fish helminth fauna of the Ayuquila River is dominated by trematode and nematode species with only a few monogenean and acanthocephalan species. The fauna exhibits considerable overlap with that reported for other freshwater basins in Mexico, and all helminths recovered have been reported previously from Mexico.

Helminth Parasites of Chapalichthys encaustus (Pisces: Goodeidae), an Endemic Freshwater Fish From Lake Chapala, Jalisco, Mexico

A total of 6 helminth species were recorded during helminthological examination of 50 Chapalichthys encaustus from Lake Chapala, Jalisco, Mexico. Helminth species identified included: Salsuginus sp. (an undescribed monogenea); Posthodiplostomum minimum (metacercariae); Cyclustera ralli (metacestode); Polymorphus brevis (cystacanth); Contracaecum sp. (nematode larvae); and Rhabdochona lichtenfelsi (adult nematode). Of these, 2 (Salsuginus sp. and R. lichtenfelsi) are specialist species. The observed species richness, individual parasite abundance, and diversity were low. Data suggest that host specificity is an important factor contributing to observed community composition and richness. Host feeding habits and helminth species availability seem to determine the characteristics of these helminth assemblages.

Helminth parasites of freshwater fish in Chiapas, Mexico.

An inventory based on previously published records and original data is presented for the helminth parasites reported in 54 fish species from 17 families from the state of Chiapas, southeast Mexico. This survey reports the presence of 43 helminth species in Chiapas for the first time. The actualized inventory of helminth parasites of freshwater fish from Chiapas contains 88 species from 67 genera and 40 helminth families. Trematodes and nematodes were the most abundant taxonomic groups. The helminth fauna in freshwater fishes from Chiapas consists of Central American species. All the helminth species recorded in Chiapas have also been collected from bodies of freshwater between the Isthmus of Tehuantepec and the Isthmus of Panama. This inventory shows that this fauna is quite similar to that from the neighboring basins of the lower Grijalva–Usumacinta system and the Yucatan Peninsula. The taxonomic composition and distribution data reported here for the helminth fauna of Chiapas’ freshwater fish, contribute to a better understanding of this faunal component in Central America.

Spinitectus mariaisabelae n. sp (Nematoda : Cystidicolidae) from the intestine of the freshwater fish Profundulus punctatus (Cyprinodontiformes) in Mexico

SummarySpinitectus mariaisabelae n. sp. is described from the intestine of Profundulus punctatus (Günther) (Pisces, Cyprinodontiformes) from the Suchiapa River, State of Chiapas, Mexico. It is characterized largely by the bifurcate distal tip of the larger (left) spicule, spination of the cuticle separated into 4 longitudinal sectors, more or less regularly spaced rings of spines, and by the position of the excretory pore just posterior to the 7th ring of visible spines. By having the rings of spines divided into 4 sectors, the new species resembles 8 of the 15 American species; however, they can be easily distinguished by the number of spines in the first ring. S. mariaisabelae differs from all its American congeners by possessing a bifurcate distal tip of the left spicule, a unique feature among Spinitectus spp.

Creptotrema agonostomi n. sp. (Trematoda: Allocreadiidae) from the intestine of freshwater fish of México.

Creptotrema agonostomi n. sp. is described from the mugilid fish Agonostomus monticola from Río Cuitzmala, Jalisco, east México, from Río Las Palmas and Río Máquinas, Veracruz, west México, and from the ictalurid, Ictalurus balsanus from Río Chontalcoatlán, Guerrero, east México. It is distinguished from other species of Creptotrema by its small size, large acetabulum with vertical incision, cirrus sac not reaching the posterior border of acetabulum, and very small eggs, measuring 0.041-0.057 x 0.020-0.033 mm.

HELMINTH PARASITES OF THE TROPICAL GAR, ATRACTOSTEUS TROPICUS GILL, FROM TABASCO, MEXICO

A total of 8 helminth species were recorded in an examination of 43 tropical gar, Atractosteus tropicus Gill, collected at the Pantanos de Centla Biosphere Reserve, Tabasco, Mexico. The parasite species included 1 adult trematode, 3 metacercariae, 1 cestode, 1 adult nematode, and 2 nematode larvae. Six of these 8 species were rare, with low prevalence (<17%) and abundance (<1.0 helminths per examined fish). The larvae of Contracaecum sp. were the most abundant in the sample, constituting 60% of the total helminths (64% prevalence, 3.8 ± 5.2 abundance), followed by the cestode Proteocephalus singularis, constituting 18% of the worms (30.5% prevalence, 1.1 ± 3.0 abundance). Species richness, individual parasite abundance, and diversity were low in the infracommunities. The recording of 3 specialist species in the tropical gar confirms that the helminth fauna of gar has an appreciable degree of specificity. This study indicates the importance of ecological determinants of richness in helminth communities of the tropical gar.

Atactorhynchus duranguensis n. sp. (Acanthocephala: Atactorhynchinae) from Cyprinodon meeki (Pisces: Cyprinodontidae) near Durango, Mexico.

Atactorhynchus duranguensisn. sp. (Acanthocephala: Atactorhynchinae) is described from the intestine of Cyprinodon meeki Miller, an endemic freshwater fish from a far-inland locality of Mexico. Diagnostic features include: body small, stout, ventrally curved; small cylindrical proboscis armed with 16 alternating vertical rows of four or five hooks; anterior two or three hooks conspicuous, stout and larger than other hooks, and have large, rod-shaped roots with a markedly and abruptly enlarged base; three posterior hooks of each row are smaller and rootless; single-walled proboscis receptacle; lemnisci equal in length, elongate and robust; and cement gland syncytial, larger than testis. The new species is smaller than A. verecundus Chandler, 1935, the only previously described species in the genus. The shape of the proboscis of the new species is strikingly different from that of A. verecundus, which is widest at the apex. Likewise, the greatest width of the trunk of the new species is in about the middle, differing from that of A. verecundus where the trunk is widest posteriorly. The new species also can be distinguished from A. verecundus because of its much smaller hook lengths and slightly smaller proboscis. In addition, the proportion of large apical proboscis hooks in relation to the small basal hooks is different: the basal hooks of A. verecundus are about half the size of the anterior hooks and but only about a quarter of the size in A. duranguensis. Unlike A. verecundus, the base of the roots are markedly and abruptly enlarged in the new species. Finally, the eggs of the new species are smaller (23–27 × 8–10 μm) than those of A. verecundus (27–30 × 12–13 μm).

Guavinella tropica n. gen., n. sp. (Monogenea: Dactylogyridae) from the Gills of the Bigmouth Sleeper, Gobiomorus dormitor (Perciformes: Eleotridae), from Mexico

Abstract The ancyrocephaline monogene Guavinella tropica n. gen., n. sp. is described from the gills of the bigmouth sleeper, Gobiomorus dormitor (Perciformes: Eleotridae), from Veracruz, Mexico. This is the first dactylogyrid reported from a Neotropical eleotrid fish.