Advances in aquatic and subterranean beetles research: a tribute to Ignacio Ribera

Abstract

It has been a bit longer than two years since our friend and colleague Ignacio (Nacho) Ribera passed away. The memory of him remains among those of us who were lucky enough to meet Nacho. This monograph is dedicated to him, bringing a set of scientific contributions from his colleagues whose topics are part of the main research lines (and passions) of his scientific work: taxonomy, systematics, biogeography and evolution of aquatic and subterranean beetles. In the last two years, several contributions have highlighted Nacho’ scientific and personal profile, including the complete list of his publications, and both the taxa described by and dedicated to him (BELLÉS, 2020; CEHRE, 2020; DELOCADO et al., 2020; FAILLE et al., 2020, 2021; JÄCH, 2020; MELIC, 2020; MILLÁN et al., 2020a, b; VALLADARES & MILLÁN, 2020). Nacho was a passionate biologist, interested in everything concerning beetles, especially their diversity, distributions, adaptations and evolution of aquatic and cave beetles. He published a total of 285 papers, in which he described 107 species new to science, highlighting the discovery of the Aspyditidae family. Besides, 7 species and subspecies, and one new genus have been dedicated to him in this monograph, extending to a total of 15 species and two genera. Concerning the aquatic beetles, we would like to emphasise his crucial contributions, such as the first complete checklist of aquatic and semi-aquatic beetles of the Iberian Peninsula. He was a pioneer in studying the adaptive morphology of the family Dytiscidae, and more importantly, he deepens in the phylogeny of the aquatic beetles, shedding light on the systematics and evolution of the families Dytiscidae and Hydraenidae. He postulated the “Habitat Constraint” hypothesis which, from an evolutionary point of view, highlights the importance of habitat stability as a determinant of species range sizes (via differences in their dispersal capabilities). He also dealt in-depth with evolutionary studies related to the habitat transition between lotic and lentic water bodies, but also the transition from freshwater to saline water, or vice versa. Certainly, Nacho, due to his work and publications on aquatic beetles, became one of the most prestigious specialists worldwide. Regarding the subterranean environment, Nacho revealed that Dalyat Mateu is a vicariant genus of carabid whose origin must be in the separation of the Iberian plate from the rest of Pangea in the Jurassic-Cretaceous boundary. He also addressed the position of Ildobates neboti Español, confirming it within the Zuphiini tribe. At the same time, he began to study the phylogeny of the hypogeal Trechini of the Pyrenees, and afterwards he addressed the diversification of Troglocharinus Reitter, opening the way to a new perspective on the evolution and dispersion of the subterranean fauna. He published the first morphological phylogeny through cladistic analysis of the Leptodirini tribe (Leiodidae), and the first molecular phylogenies for the two main groups that have colonised the subterranean environment, the tribes Leptodirini and Trechini. His contribution to the knowledge of underground and stygobic environments between 2005 and 2021, postulated him as one of the most important specialists worldwide also in this field. The complete list of scientific works signed by Nacho, the taxa described by him and those dedicated to his person can be found on the web: https://www.um.es/ecoaqua/index.php/external-collaborators. We do not want to extend further. We hope these pages serve as a tribute to his person, but also a tribute to a life and scientific style that would serve as an example for future generations of insect lovers. Our gratitude to the authors and reviewers of the articles that make up this monograph, as well as to the Asociación española de Entomología, which has greatly facilitated its preparation, edition and publication.