Abstract Presently, demyelinating diseases have been reported to affect the reproductive life of patients who suffer from them, but the progression of the alterations is unknown, especially in men. To better understand these effects, it is necessary to perform studies in animal models, such as the male taiep rat, which exhibits progressive demyelination of the central nervous system, altered kisspeptin expression at the hypothalamic level, and decreased luteinizing hormone, which could alter sperm quality and testicular diameter. Thus, the objective of the present study was to analyze the diameter of the seminiferous tubules, the sperm motility, and the testosterone levels of 90-day-old male taiep rats. The obtained results indicate that male taiep rats show an increase in testicular size accompanied by an increase in the diameter of the seminiferous tubules of the left testicle. There was also a decrease in progressive motility in sperm samples from the left epididymis of male taiep rats compared to the control group, with no changes in serum testosterone concentration. Therefore, we conclude that male taiep rats with central demyelination show altered testicular diameter and decreased motility in sperm from the left side. This type of studies serves as a basis for proposing possible reproductive strategies to improve the fertility and testicular function of men with demyelinating diseases of the central nervous system.

Abstract The study of the early Miocene amber of Simojovel de Allende, Chiapas, has taken a great interest, since it has been perceived that its study allows us to demonstrate an estuarine environment during its deposit. In this work, the identification of 34 specimens present in a piece of amber belonging to Museo del Ámbar Lilia Mijangos, with an approximate age of 20 million years, was carried out. The organisms were assigned to Martesia mazanticus sp. nov., considered as a new taxon due to the existing differences with the more related species M. fragilis, and M. sanctipauli. This is the first record of the genus Martesia in Simojovel amber. This finding reinforces the proposed theory of the presence of an estuarine lagoon surrounded by a Rhizophora mangrove as a deposit environment.

Resumen El estudio del ámbar del Mioceno temprano de Simojovel de Allende, Chiapas, ha tomado gran auge, ya que se ha visualizado que su estudio nos permite evidenciar el ambiente durante su depósito. En este trabajo se realizó la identificación de 34 especímenes presentes en una pieza de ámbar perteneciente al Museo del Ámbar Lilia Mijangos, con una edad aproximada de 20 millones de años. Los organismos fueron asignados a Martesia mazanticus sp. nov., considerada como nuevo taxón por las diferencias presentadas con las especies más afines M. fragilis y M. sanctipauli. Este es el primer registro del género Martesia en el ámbar de Simojovel. El presente hallazgo refuerza la teoría planteada de la presencia de una laguna estuarina rodeada de un manglar de Rhizophora como ambiente de depósito.