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A helminthological examination was performed on 114 specimens of sciaenids that were captured on the Alvarado coast, Veracruz, Mexico, between August 2004 and July 2006. Bairdiella chrysoura (n = 15); Cynoscion arenarius (n = 31); Menticirrhus americanus (n = 16); Menticirrhus littoralis (n = 33) and Umbrina coroides (n = 19). 26 parasites were identified at the species, 12 genus and 5 family levels, as follows: 21 digeneans (14 adults and 7 metacercariae), 9 monogeneans, 7 nematodes (4 adults and 3 larvae), 2 cestodes (larvae), and 4 acanthocephalans (adults). Digeneans and monogeneans were the most abundant. Helminths with the highest prevalence in all five communities were Pseudorhamnocercoides stichospinus and Tetraphyllidae. The species with highest mean intensity were Diplomonorchis leiostomi and Tetraphyllidae, and Hysterothylacium sp., were registered in the five communities. Significant correlations between the host total length and species richness, U. coroides (r = 0.54), and total length and abundance, M. americanus (r = 0.63), were found. The highest similarity was recorded among communities of M. americanus and M. littoralis. The infracommunities and component communities in species richness and diversity, in all cases, were within ranges observed in most marine fish helminth communities.

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A new species of crayfish is described from the Cave of Sótano de La Lucha, in the border between the Mexican states of Chiapas and Oaxaca. The new species is completely adapted to the cave environment with reduced eyes lacking cornea and visual pigments, an almost unpigmented body and elongated appendages. We also report on crayfish populations from the "Lagunas de Montebello" area, which fit well the description of Procambarus pilosimanus (Ortmann, 1906), a heretofore problematic species in southern Mexico.