A new flower preserved in amber in sediments of Simojovel de Allende, México, is identified as an extinct member of Staphyleaceae, a family of angiosperms consisting of only three genera (Staphylea, Turpinia and Euscaphis), which has a large and abundant fossil record and is today distributed over the Northern Hemisphere. Staphylea ochoterenae sp. nov. is the first record of a flower for this group, which is small, pedicelled, pentamer, bisexual, with sepals and petals with similar size, dorsifixed anthers and superior ovary. Furthermore, the presence of stamens with pubescent filaments allows close comparison with extant flowers of Staphylea bulmada and S. forresti, species currently growing in Asia. However, their different number of style (one vs. three) and the apparent lack of a floral disc distinguish them from S. ochoterenae. The presence of Staphyleaceae in southern Mexico ca. 23 to 15My ago is evidence of the long history of integration of vegetation in low-latitude North America, in which some lineages, such as Staphylea, could move southwards from high latitudes of the Northern Hemisphere, as part of the Boreotropical Flora. In Mexico it grew in association with tropical elements, as suggested by the fossil record of the area.

Paleobotany bears an invaluable source of knowledge for understanding the history of the biodiversity that we protect and care for today. This discipline is recognized as a source of information on physical, ecological, and biological events and processes that occurred in the past and are maintained today, but whose occurrences must be interpreted necessarily, and sometimes with limitations, solely from the lithosphere. The importance of studying past life from Mexico and addressing fossil plant reconstruction is highlighted to understand modern biodiversity. Fossils in Mexico have been studied marginally but contain valuable information to understand the history of biodiversity, both in Mexico and globally. We examined the extent to which Mexican fossils can contribute to understanding the origin and development of biological processes through time, and how past plant biodiversity in Mexico compares with the extant one. We used two sources to address these questions: (i) ideas on biological processes as seen through the fossil record, and (ii) fossils known from Mexico. Examples are given of how fossils, morphology, anatomy, and numerical methods, as well as genetics and physiology, illuminate each other to generate solid botanical concepts. The abundant and widely distributed outcrops with fossil plants suggest that further studies on Mexican material will be influential for varied biological hypotheses related to the origin and history of biodiversity. Mexican fossil plants and their scarce sampled localities are open to further investigation that will complement hypotheses on the historic discussion of biological processes.

Water issues in Mexico City have been severe during the last years due to population increase, forcing external water sources to meet water demands. This research aims to evaluate the evolution of water vulnerability in the sixteen municipalities of Mexico City in the years 2005, 2010, and 2015. This vulnerability has increased in the last decades due to the combination of several problems such as lack of maintenance in the water infrastructure (eg. water leaks), aquifer overexploitation, uncontrolled city growth, rainwater and wastewater expelled from the basin without the intention of using it. For the vulnerability assessment we used a combination of indicators that respond to its three dimensions: 1). Exposure (urbanization, population, and economic units), 2). Sensitivity (reports of leaks, shortages, and poor water quality) and 3). Adaptive capacity (wastewater treatment, water availability, and GDP). The municipalities identified with very high vulnerability in the three years of study (2005, 2010, and 2015) were Iztapalapa, Gustavo A. Madero, and Tlalpan joined these during 2015. In contrast, those with the lowest vulnerability were Milpa Alta, Magdalena Contreras, and Cuajimalpa; the latter stepped down from having Low to Very Low vulnerability between 2005 and 2010-2015. Between these two classifications, we have the Municipalities that reveal high, moderate, and low vulnerability. The results highlight that all municipalities must prevent water leaks to achieve increasingly sustainable management of the liquid, especially Gustavo A. Madero, Iztapalapa, and Tlalpan. Suggesting that harmonized action among all of them will help accelerate goal achievement. Still, citizen action will play a leading role in maintaining care and water usage levels when promoted and encouraged adequately. At the end of the lecture, the reader would be able to discuss if a series of social elements (like the indicators proposed in this work) construct water vulnerability or depend on the quantity of water the cities receive. Also, they will understand their role in water management and have factors to evaluate vulnerability in other regions.