Mangrove forests of Mexico have been threatened by the effects of anthropogenic activities during the last decades, mostly related to aquaculture, agriculture, livestock and urban development. Genetic diversity and fine-scale genetic structure of two generations of the black mangrove Avicennia germinans (L.) Stearn were investigated in perturbed and preserved sites from three lagoon systems in Sinaloa, Mexico. Genetic diversity and overall genetic structure were similar between perturbed and preserved sites. However, lower levels of fine-scale spatial genetic structure were observed in two of the younger (sapling) generations. We attribute this to differences in local dynamics of each lagoon system, their status of conservation and levels of fragmentation. Also, low connectivity and the effects of disturbance could restrict the movement of pollinators and seed dispersal capabilities, resulting in low levels of genetic diversity and signs of inbreeding. Perturbed populations of A. germinans may play an important role in in situ conservation of this complex ecosystem.

The Asian fish tapeworm, Bothriocephalus acheilognathi, has been considered one of the most dangerous parasites for cultured carp and a risk for native freshwater fish populations worldwide. This cestode is highly pathogenic for fishes especially fry. In this paper we record B. acheilognathi parasitizing the endangered and endemic freshwater fish Profundulus hildebrandi from the endorheic basin of San Crist6bal de las Casas, Chiapas, Mexico. B. acheilognathi was recorded from 10 of the 11 sampled localities, with high values of prevalence (> 60%) and mean abundance (> 4.50). The infection was persistent all through the year; gravid cestodes were recorded in all samples. It is assumed that B. acheilognathi entered to this area through the introduction of common carp Cyprinus carpio, for aquacultural purposes. The data presented in this paper document the successful introduction, colonization and establishment of this alien species into the endangered P. hildebrandi.

Until recently, the genus Profundulus was classified in two subgenera, Profundulus and Tlaloc, the sole members of the family Profundulidae. Newly discovered molecular data have been used to justify the elevation of these subgenera to genera. Yet morphological analyses to diagnose the two genera are lacking. The aim of this study is to provide a generic diagnosis and a taxonomic key to the species within the family Profundulidae based on morphology. The genus Tlaloc is diagnosed on the basis of five unique characters, among which are the prominent and oval-shaped mesethmoid, exceeding the posterior margins of the vomer; the anterior portion of the parasphenoid making contact with the mesethmoid and extend beyond the center of the mesethmoid; and a reduced autopterotic fossa. Profundulus is diagnosed here based on the following characters: the mesethmoid is small, crescent-shaped, and does not extend beyond the margins of the vomer; the anterior portion of the parasphenoid just contacting the mesethmoid and not extending beyond the center of the mesethmoid; a large autopterotic fossa. For each genus, description and distribution ranges are provided as well as a key for identification of the species.

The Middle American killifish genus Profundulus occurs in most Pacific and Atlantic drainages from the Mexican state of Guerrero to the Chamelecón River in Honduras, with highest species diversity in southern Mexico. In this study, we describe a new member of the genus, Profundulus parentiae, new species, from the Mexican state of Oaxaca. It is distinguished from P. guatemalensis and P. kreiseri by having rows of dots on the sides of the body. Profundulus parentiae, new species, can be distinguished from P. oaxacae by having 33 lateral scales, versus 29–31 in P. oaxacae. Profundulus parentiae, new species, can be distinguished from P. balsanus, P. oaxacae, and P. mixtlanensis by the presence of long epiotic processes that extend beyond the epipleural ribs of the first vertebra, versus short epiotic processes not reaching the epipleural ribs of the first vertebra. Profundulus parentiae, new species, can be differentiated from P. punctatus by the presence of a dorso-ventrally compressed Meckel's cartilage with a relatively straight medial process and a narrow and strongly concave sesamoid articular, versus a dorso-ventrally expanded Meckel's cartilage with concave medial process and a wide and moderately concave sesamoid articular. Based on the phylogenetic analysis of molecular sequence data, the new species is recovered as the sister taxon to P. balsanus. The discovery and description of this new species in southeastern Mexico, raises the number of species from this region to five and suggests that this area has been an important center for diversification within this lineage of killifishes. El género Profundulus son escamudos de América-Media que ocurren en la mayoría de cuencas del Pacifico y Atlántico, desde el estado de Guerrero hasta la zona central de Honduras, presentando los niveles más altos de diversidad en el sureste de México. En este estudio describimos un nuevo miembro de este género, Profundulus parentiae sp. nov., del estado de Oaxaca, Mexico. Se distingue de P. guatemalensis y P. kreiseri por tener líneas de puntos a los lados del cuerpo. Profundulus parentiae se puede distinguir de P. oaxacae por tener 33 escamas laterales, versus 29–31 en P. oaxacae. Profundulus parentiae sp. nov. se puede distinguir de P. balsanus, P. oaxacae y P. mixtlanensis por la presencia de un proceso epiotico alargado que se extiende por debajo de la costilla epipleural de la primera vertebra, versus un proceso epiotico corto que no llega a la costilla epipleural de la primera vertebra. Profundulus parentiae sp. nov. se puede diferenciar de P. punctatus por la presencia de un cartílago de Meckel comprimido dorso-ventralmente con un proceso medial relativamente recto y un angosto y fuertemente cóncavo sesamoideo articular, versus un cartílago de Meckel expandido dorso-ventralmente con un proceso medial cóncavo y un sesamoideo articular ancho y moderadamente cóncavo. Basados en los análisis filogenéticos con datos de secuenciaciones moleculares, la nueva especie se recobró como taxón hermano de P. balsanus. El descubrimiento y descripción de esta nueva especie in el sureste de México, aumenta el número de especies en esta región a cinco, y sugiere que esta área ha sido un importante centro para la diversificación para este linaje de escamudos.

Profundulus adani, new species, is described from the upper reaches of the Papaloapan River in the Mexican state of Oaxaca. The uniqueness of this new species is supported by morphological and molecular evidence. A combination of color patterns and counts separate P. adani, new species, from its congeners. Profundulus adani, new species, is distinguished from all congeners by the absence of a humeral spot in individuals larger than 45 mm SL. It can further be distinguished from P. balsanus, P. chimalapensis, P. kreiseri, P. oaxacae, P. parentiae, and P. punctatus based on the absence of series of dark dots on the sides of the body. Profundulus adani, new species, shows a faded dark band that extends from the tip of the operculum to the end of the caudal peduncle; this band is absent in P. balsanus and P. parentiae. The new species is described using specimens collected in the upper reaches of the Papaloapan River in the Mexican state of Oaxaca; geographically this represents a significant range expansion and extends the Atlantic slope northernmost limit of the Profundulidae.