Toxoplasma gondii has at least 318 genotypes distributed worldwide, and tropical regions usually have greater genetic diversity. Campeche is a state located in the southeastern region of México and has favourable climate conditions for the replication and dissemination of this protozoan, similar to those in South American countries where broad genetic diversity has been described. Thus, in this study, 4 T. gondii isolates were obtained from tissues of stray dogs and free-range chickens in Campeche, México, and were genotyped by Mn-PCR-RFLP with 10 typing markers (SAG1, altSAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) and 5 virulence markers (CS3, ROP16, ROP17, ROP18 and ROP5) to provide new information about the distribution and virulence prediction of T. gondii genotypes. Two isolates of T. gondii genotype #116 and 2 of genotype #38 were obtained from stray dogs and chickens, respectively. The parasite load found in these species was between <50 and more than 35 000 tachyzoites per mg of tissue. Virulence marker genotyping revealed a recombinant 1&3 ROP5 RFLP pattern in 2 ToxoDB #116 isolates with no prediction of virulence in a murine model, while in the 2 ToxoDB #38 isolates, the ROP18/ROP5 combination predicted high virulence. Considering all the typed markers, there is a predominance of type I and III alleles, as constantly reported for the isolates characterized in various regions of México. It is crucial to determine their phenotype to corroborate the genetic virulence profile of the T. gondii isolates obtained in this study.

Gypsophily, i.e. the relationship between plants and gypsum soils, has been extensively studied only in arid and semi-arid regions, in contrast to tropical areas, where gypsum outcrops act as refugia for xerothermophilic species and endemic flora. We focused on gypsophile flora in Campeche, Mexico on the Zoh-Laguna Plateau. Using a combination of remote sensing, literature review, and herbarium databases, we identified 14 potential gypsum outcrops and compiled a list of vascular plant species with the potential to grow in gypsum soils in Campeche (151 total species: three probable gypsophiles and endemic to YP, 148 gypsovags). Nine of the 14 potential gypsum outcrops remain unexplored botanically, and 18 species in the final checklist were not previously reported to have an affinity for gypsum soils. This study is the first to confirm the presence of gypsum and report its concentration in the evaluated soils; gypsum content in the soils reached 51%, much higher than the commonly accepted 25%. Our results on gypsum soils and associated vegetation confirm the need for more extensive gypsophily studies in tropical zones.

Campeche, one of the Spanish Empire's main Mexican ports, was a place where previously distinct cultures and populations intermingled during the colonial era (AD 1540–1680). Investigation of the town's central plaza revealed a Hispanic cemetery of multi-ethnic burials. The authors combine previous analyses with newly generated genome-wide data from 10 individuals to trace detailed life histories of the mostly young, local Indigenous Americans and first-generation European and African immigrants, none of whom show evidence of genetic admixture. These results provide insights into the individual lives and social divides of the town's founder communities and demonstrate how ancient DNA analyses can contribute to understanding early colonial encounters.

The fragmentation of jaguar Panthera onca populations as a result of habitat loss is considered to be one of the main challenges for the conservation of the species. Corridors have been proposed as a means of maintaining connectivity and the long-term viability of jaguar populations. The corridor that connects the jaguar conservation units of Calakmul and Laguna de Terminos in Mexico has been considered to be a link for the movement of individuals between these units but its functionality had yet to be verified. During 2012–2014 we divided the corridor into four sections, where we used camera traps to verify the corridor's functionality. We obtained 106 photographs of jaguars, proving the presence of jaguars (including resident jaguars and females) in three of the corridor sections. We did not record any individuals in more than one section of the corridor. The presence of several resident jaguars and females throughout the corridor suggests that portions of the corridor should be incorporated into the Calakmul and Laguna de Terminos jaguar conservation units. Nevertheless, to confirm that the corridor is fully functional it is necessary to obtain evidence of movement of jaguars among the various sections of the corridor. Our results suggest that the area should be included in regional conservation strategies.

High plasticity in cephalopod populations shows dramatic changes in their biological traits. Commercial catches of Mayan octopus (Octopus maya) in six localities of the state of Campeche, Mexico, were sampled monthly for five consecutive fishing seasons (2005–2009) in order to describe variations in population structure and maturation. Octopus maya grows and matures during the fishing season, from August to December. Spent individuals predominate in January and February, revealing a year-long life cycle. However, the presence of a few spent females in all months sampled suggests that a small part of the population shows an extended spawning period. Overall sex ratios did not significantly shift from the expected 1:1 in most samples. Males are mostly mature while the majority of females are immature during the season. Use of illegal fishing gears (spear diving or pots) in central localities accounts for a larger share in mature females. Octopus size showed large interannual and geographic differences. Females mature at a larger size (1024 g body weight, BW; 124 mm mantle length, ML) than males (484 g BW; 91 mm ML). Size at maturity in both sexes varies more between seasons than between localities. Female ML at maturity is larger than the current minimum legal size and implications for current octopus fishing regulations are discussed.