Eugerres castroaguirrei González-Acosta et Rodiles-Hernández, 2013 is a junior synonym of Eugerres mexicanus (Steindachner, 1863) (Actinopterygii: Perciformes: Gerreidae)

Abstract

Background. The Lacandon mojarra, Eugerres castroaguirrei González-Acosta et Rodiles-Hernández, 2013, was described from the Grijalva-Usumacinta River basin (Mexico). According to the diagnosis E. castroaguirrei differs from the only other freshwater Gerreidae, the Mexican mojarra, Eugerres mexicanus (Steindachner, 1863) by the combination of certain morphological characters. However, a comparison of materials obtained in the Usumacinta River, besides of type materials and other preserved specimens, yielded contradictory results. Therefore, the objective of this paper was to clearly determine if E. mexicanus and E. castroaguirrei are subjective synonyms applying morphological and molecular analyses. Materials and methods. A total of 44 specimens were included in this study including the specimens collected specifi cally for this study, the type and non-type materials of Eugerres castroaguirrei from Colección de Peces de El Colegio de la Frontera Sur, Unidad San Cristóbal, Chiapas, México, and the types of Eugerres mexicanus, belonging to the Museum of Natural History, Wien, Austria. The morphological comparison also included data from the 42 specimens of E. castroaguirrei reported in the new species description. Biometric data were analysed as body proportions. We used Friedman's test to compare our biological materials with those used in the new species description. Molecular genetics comparisons on both putative freshwater gerreid species were made based on three mitochondrial gene fragments: 12SrRNA, 16SrRNA, and Cytochrome Oxidase subunit I (COI), and the nuclear gene: Recombination-Activating protein 1 (RAG1). Results. Neither the non-parametric Friedman's test nor the Nemenyi's procedure showed differences among individuals for both putative species in multiple pair-wise comparisons of body proportions. Moreover, the genetic divergence from all genes indicated that all individuals exhibited almost identical sequences, with inter-specifi c pair-wise genetic distances that ranged from 0.00% to 0.100% in all of the fragments. Conclusion. Our morphological and molecular genetics analyses demonstrated that E. mexicanus and E. castroaguirrei are subjective synonyms, therefore, Eugerres mexicanus (Steindachner, 1863) must be considered a valid species name, and Eugerres castroaguirrei González-Acosta et Rodiles-Hernández, 2013 a junior synonym.

Supporting the existence of two isolated evolutionary lineages ofGerres(Perciformes: Gerreidae) in America

“…In our study, the divergence was supported by not only mtDNA sequences but also nDNA information, particularly by the RAG1 partial gene, which has been used in taxonomic and phylogenetic studies of the family Gerreidae (Chen et al, ; Martínez‐Guevara et al, , ; Vergara‐Solana, García‐Rodriguez, et al, ). Although specimens of G. simillimus and G. cinereus have genetic differences, their divergence was relatively low in relation to other species in the same family.…”

“…In recent years, several studies of the family Gerreidae have used the urohyal bone, sagittae otoliths (hereinafter, otoliths), morphometric body characters and molecular markers to resolve the taxonomic problems of some species and genera of mojarras in the Neotropics (e.g., Chollet‐Villalpando, De La Cruz‐Agüero, & García‐Rodríguez, ; De La Cruz‐Agüero et al, ; De La Cruz‐Agüero et al, ; Martínez‐Guevara et al, ; Martínez‐Guevara, García‐Rodríguez, & De La Cruz‐Agüero, ; Vergara‐Solana, García‐Rodríguez, & De La Cruz‐Agüero, ; Vergara‐Solana, García‐Rodriguez, et al, ).This multisource approach intends to incorporate all the available information when defining the limits between species.…”

Anatomy of the visceral cavity of Eugerres mexicanus (Teleostei: Gerreidae)

“…Anatomy of the visceral cavity of Eugerres mexicanus (Teleostei: Gerreidae). Revista de Biología Tropical,68(1), 189-199. Eugerres castroaguirrei as a new species, Martínez-Guevara et al (2015), synonymized as E. mexicanus by means of morphological and molecular analyses. The Mexican mojarra is distributed in Southeastern Mexico and Northern Guatemala (Miller et al, 2005).…”

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

“…In general, fish body form results from interactions among the skeleton and muscle mass, and the evolutionary adaptations of the diverse species (Helfman et al, 1997). The external anatomy of Osteichthyes fishes has a wide variety of forms, with many exhibiting modifications such as barbels (e.g., Sciaenidae: Menticirrhus ), spiny plates as scutes (e.g., Carangidae: Caranx ), serrations in preopercle and preorbital bones (e.g., Gerreidae: Eugerres ) (Bussing, 1995), dorsal fins separated and preopercle serrated (Gerreidae: Deckertichthys , Vergara‐Solana et al, 2014), more compressed bodies and rostrum elongate (Gerreidae: Eucinostomus , De La Cruz‐Agüero et al, 2015), and morphological alteration in their lips (Gerreidae: Eugerres , Martínez‐Guevara et al, 2015). Analyzing morphological variation in fishes is therefore fundamental to determine how they have evolved to adapt to the environment.…”