Molecular Phylogenetics of the New-World Crocodylia

During the late twentieth and early twenty-first centuries, there has been a revolution in evolutionary biology. Traditional methods that had been applied to understanding relationships and natural history for hundreds of years have been supplemented (and sometimes replaced) by biochemical and molecular techniques that now allow us to examine the entire genomes of non-model organisms. Herein we review the use of these new technologies as they apply to crocodylians in general and specifically to the New-World members of the Alligatoridae and Crocodylidae. While generally concordant with traditional analyses, in some cases they have permitted cryptic species to be recognized. In addition, they have allowed crocodylian biologists to detect hybridization events between species, both in captivity and in the wild, that would not have been possible before their use. Hybridization may lead to the formation of new species, but it may also allow a common species to “swamp out” a rarer one. Because there appears to be little hybrid dysgenesis between many of the potential hybridizing forms, hybridization is potentially a serious problem for several New-World species

An Amphisbaenian Skull from the European Miocene and the Evolution of Mediterranean Worm Lizards

<div><p>The evolution of blanid amphisbaenians (Mediterranean worm lizards) is mainly inferred based on molecular studies, despite their fossils are common in Cenozoic European localities. This is because the fossil record exclusively consists in isolated elements of limited taxonomic value. We describe the only known fossil amphisbaenian skull from Europe – attributed to <i>Blanus mendezi</i> sp. nov. (Amphisbaenia, Blanidae) – which represents the most informative fossil blanid material ever described. This specimen, from the Middle Miocene of Abocador de Can Mata (11.6 Ma, MN7+8) in the Vallès-Penedès Basin (Catalonia, NE Iberian Peninsula), unambiguously asserts the presence of <i>Blanus</i> in the Miocene of Europe. This reinforces the referral to this genus of the previously-known, much more incomplete and poorly-diagnostic material from other localities of the European Neogene. Our analysis – integrating the available molecular, paleontological and biogeographic data – suggests that the new species postdates the divergence between the two main (Eastern and Western Mediterranean) extant clades of blanids, and probably precedes the split between the Iberian and North-Western African subclades. This supports previous paleobiogeographic scenarios for blanid evolution and provides a significant minimum divergence time for calibrating molecular analyses of blanid phylogeny.</p></div

The taxonomic impediment: A shortage of taxonomists, not the lack of technical approaches

For almost 30 years, there have been active discussions about the taxonomic impediment and the challenge this represents to address the current human-induced biodiversity crisis. From the start (Systematics Agenda 2000, 1994), the term ‘taxonomic impediment’ has been ambiguous, designating both the insufficiency and inadequacy of the resources put to the service of taxonomy (the taxonomic impediment sensu stricto) and its main consequence, the wide discrepancy between the reality of specific biodiversity and our knowledge of it (the taxonomic gap; Dubois, 2010; Raposo et al., 2020). The total number of species on our planet is unknown, and its various estimates (using different methods) are widely divergent, but consensus exists that we are far from having inventoried half, and most likely one-tenth, of the species still present on earth today (González-Oreja, 2008)