**5. Conclusions**

The historical analysis of zooplankton composition in the lake presented in this study reinforces the knowledge of its eutrophic state, suggesting a useful role of the zooplankton as a bioindicator and making possible the visualization of the changes in its composition over time, showing the progressive trophic state towards eutrophic or hypereutrophic conditions.

It is likely that the absence of the endemic species *M. amatitlanensis* is a warning sign regarding the accelerated loss of biodiversity and reinforces the idea that zooplankton is a great tool as a bioindicator of the health status for continental aquatic ecosystems, in both tropical and temperate latitudes.

Further studies analyzing bottom sediments to search resting eggs of zooplankton in Lake Amatitlán and around it can answer the question of the absence of *M. amatitlanensis*, where this type of knowledge is also scarce in inland aquatic systems of the region.

Finally, is convenient to consider the isolated site EC as a focal point for conservation as it presents better environmental conditions for the conservation and preservation of zooplankton biodiversity, owing to the record of the largest zooplankters found in this site.

**Author Contributions:** Conceptualization, S.J. and A.C.-M.; methodology, S.J., A.C.-M., M.A.G.-A., E.S.-M., J.R.J.-P., E.M.R.-S. and V.H.D.-B.; software, S.J.; validation, S.J., A.C.-M., M.A.G.-A., E.S.-M., J.R.J.-P., E.M.R.-S. and V.H.D.-B.; formal analysis, S.J., A.C.-M., M.A.G.-A., E.S.-M., J.R.J.-P., E.M.R.-S. and V.H.D.-B.; investigation, S.J., A.C.-M., M.A.G.-A., E.S.-M., J.R.J.-P., E.M.R.-S. and V.H.D.-B.; resources, J.R.J.-P. and E.M.R.-S.; data curation, S.J.; writing—original draft preparation, S.J.; writing review and editing, S.J., A.C.-M., M.A.G.-A., E.S.-M., J.R.J.-P., E.M.R.-S. and V.H.D.-B.; visualization, S.J. and A.C.-M.; supervision, S.J. and A.C.-M.; project administration, S.J., A.C.-M., M.A.G.-A., E.S.-M., J.R.J.-P., E.M.R.-S. and V.H.D.-B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Council of Science and Technology (CONACYT) with the Investigator SNI-III Assistant Program, Grant Number 19812.

**Institutional Review Board Statement:** Zooplankton collected in this study was provided by AMSA in Guatemala. Zooplankton is not under any protection by Guatemalan laws; therefore, no specific permits are required for this kind of field.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author due to the need of further use to complete the first author's postgraduate requirements.

**Acknowledgments:** We gratefully acknowledge the invitation of Manuel Elías-Gutiérrez to contribute to this special issue of the Selected Papers from 1st International Electronic Conference on Biological Diversity, Ecology, and Evolution, and his valuable suggestions that made possible this research. We acknowledge AMSA for all the biological material and data bases that made possible the present study. Anonymous reviewers made valuable comments and suggestions. University of Quintana Roo, Cozumel with the investigation group vulnerability of continental and coastal water systems and the National Council of Science and Technology (CONACYT) with the Investigator SNI-III Assistant Program (Number 19812) provided financial support.

**Conflicts of Interest:** The authors declare no conflict of interest.
