Parasite Community Analysis of The Gray Snapper Lutjanus Griseus (Perciformes,Lutjanidae) in a Tropical Region of The Southern Gulf of Mexico.

The gray snapper Lutjanus griseus is a commercially important fish species along its distribution range in the western Atlantic Ocean. However, despite its importance, there is still little knowledge about its parasitic fauna for the Mexican coasts of the Gulf of Mexico. The aims of this research were to generate a list of the parasitic fauna present in juvenile gray snapper L. griseus from a coastal lagoon located in southeastern Mexico, to evaluate the infection levels of parasites and to determine the relationship between the abundance of parasites and the fish size and condition factor. Samples of L. griseus (12 - 29.2 mm) were obtained in two periods of the year (dry and rainy seasons) to examine the intra-annual variability of its parasitic fauna. A total of 17 parasite species were recorded belonging to six taxonomic groups (Myxozoa, Monogenea, Digenea, Cestoda, Nematoda and Acanthocephala). The highest levels of infection (abundance, prevalence and intensity of infection) were found for the monogeneans Euryhaliotrema griseus and Euryhaliotrema fastigatum. There were no significant correlations between the total abundance of parasites and the fish condition and size (total length) in not any of the two seasons studied, suggesting that the body size and the biological condition index of the host did not directly influence the abundance of parasites in early life stages of L. griseus. Moreover, the species of parasites found that could be zoonotic for humans through the consumption of raw or inadequately cooked fish were the nematodes Contracaecum sp. type 1, Contracaecum sp. type 2, Cucullanus pargi and Pseudoterranova sp. The presence of the monogeneans E. griseus and E. fastigatum was also highlighted because these ectoparasite species are known to cause harm to fish under culture systems. All the parasite species found in this study, except nematodes, were new records of geographic distribution.

Spirocamallanus rebecae sp. n. (Nematoda: Camallanidae) from freshwater fishes in south-eastern Mexico.

Spirocamallanus rebecae sp. n. is described from freshwater cichlids in some lakes of Southeast Mexico. It has 14 spiral bands in the buccal capsule, similar unequal spicules 503-544 and 281-297 long, 3 precloacal and 6 postcloacal pairs of papillae, vulva situated in the middle part of the body. An updated list of the species of the genus is presented.