Character variation in separate body regions of Gerreidae (Osteichthyes: Teleostei) fishes inferred from geometric morphometrics.

Body morphology is a valuable feature for distinguishing teleostean fishes. However, the utility of character variation in separate body regions has yet to be tested. The taxonomy of the Gerreidae family is controversial due to character overlapping among its fish species. This work aims to analyze and compare the body shape variation in three regions, cephalic, trunk, and caudal peduncle, using landmark data and geometric morphometric methods in 17 species and five genera of the family Gerreidae. The pattern of shape variation for the cephalic region consisted of well-defined character states exclusive of each species analyzed. Shape variation in the trunk and caudal peduncle regions does not distinguish all species in this study. This study showed that the dorsal cephalic profile is highly variable among the species, therefore, shape variation in this region is useful for distinguishing Gerreidae species. In contrast, some species within the same genus share similar shape states in the trunk and caudal peduncle regions, with the most shape variation in the dorsal profile and anal fin for the trunk and in the middle of the caudal peduncle.

Updated checklist of the extant Chondrichthyes within the Exclusive Economic Zone of Mexico.

The checklist presented in this study includes the latest taxonomic and systematic modifications and updates (early 2018) for the Chondrichthyes that inhabit the Exclusive Economic Zone (EEZ) of Mexico. The list is based on a literature review of field-specific books, scientific publications and database information from collections and museums worldwide available online such as, the Ocean Biogeographic Information System (OBIS), Global Biodiversity Information Facility (GBIF), Encyclopedia of Life (EOL), iSpecies, FishBase and the National Biodiversity Information System (SNIB-CONABIO). Information was cross-referenced with digital taxonomic systems such as the Catalog of Fishes of the California Academy of Sciences, the World Register of Marine Species (WoRMS), and the Integrated Taxonomic Information System (ITIS). There is a total of two subclasses two divisions, 13 orders, 44 families, 84 genera, and 217 species that represent approximately 18% of all living and described species of chondrichthyans worldwide. For the Mexican Pacific and the Gulf of California, 92 species of chondrichthyans are listed compared to 94 species for the Gulf of Mexico and the Caribbean Sea. Additionally, 31 species listed occur on both coasts of Mexico. The species richness of the Mexican chondrichthyans will surely continue to increase, due to the exploration of deep-water fishing areas in the EEZ.