Raquel López-Antoñanzas

Byzantinia is a genus of extinct cricetodontine rodents with a distribution centered in the eastern Mediterranean (Greece, Turkey, and Lebanon) and extending into Romania. It originated during the Middle Miocene in Anatolia and became extinct at the end of the Miocene, its last representatives being Byzantinia pikermiensis , B. uenayae , and B. hellenicus . Several isolated molars attributed to B. pikermiensis and B. hellenicus have been recovered from a newly discovered fossiliferous locality in Lebanon (Zahleh 16). This material provides new insights into the occlusal morphology of the genus and allows the identification of several evolutionary trends. The co-occurrence of B. pikermiensis and B. hellenicus suggests an age of 8.9–7.5 Ma for Zahleh 16. Given that the earliest record of Byzantinia in Lebanon dates to ca. 10.9–10 Ma, these findings indicate that the presence of the genus in this area persisted for more than 1 million years.

Rodents constitute the most diverse order of mammals, representing nearly half of all living mammalian species (Blanga-Kanfi et al., 2009; Fabre et al., 2012; Maxeiner et al., 2025). They are found...

Background: The systematics of extant hamsters (Cricetinae) have been increasingly clarified, due to advances in molecular phylogenetics. In contrast, their relationships with their fossil relatives have remained relatively unclear. Furthermore, studies on the biogeographical history and divergence times of the main groups of extant hamsters have so far been limited to molecular phylogenies and node dating approaches. Results: Here, we present the first ‘total-evidence’ analysis of hamsters that combines extinct and extant taxa, based on a comprehensive dataset covering 82 species (~ 75% of the total known diversity of 109 species). We performed a relaxed-clock Bayesian phylogenetic reconstruction and used the resulting tip-dated tree to estimate ancestral geographic ranges. Our results confirm ‘† Kowalskia’ as a synonym of † Neocricetodon , support the previously suggested non-monophyly of † Allocricetus , † Cricetulodon , and ‘† Cricetinus’ and reveal several fossil taxa as potential close relatives of the crown group. We recover a Pliocene origin of the crown hamsters, considerably younger than previous estimates of a late/middle Miocene origin. Our biogeographic reconstructions suggest a Central and Eastern European origin of the entire group, with crown hamsters emerging in the region around the Black Sea and the Eastern Mediterranean. Subsequent dispersal events into Western Europe and East Central Asia may be linked to the expansion of open vegetation. Conclusions: Based on a total-evidence phylogenetic reconstruction, we highlight necessary taxonomical revisions for several fossil cricetine taxa and explore the biogeographical evolution of the group. Importantly, our estimated divergence dates reveal a substantially younger group of crown hamsters than previously assumed.

Background: Extinct organisms provide vital information about the time of origination and biogeography of extant groups. The development of phylogenetic methods to study evolutionary processes through time has revolutionized the field of evolutionary biology and led to an unprecedented expansion of our knowledge of the tree of life. Recent developments applying Bayesian approaches, using fossil taxa as tips to be included alongside their living relatives, have revitalized the use of morphological data in evolutionary tree inferences. Eumuroida rodents represent the largest group of mammals including more than a quarter of all extant mammals and have a rich fossil record spanning the last ~ 45 million years. Despite this wealth of data, our current understanding of the classification, major biogeographic patterns, and divergence times for this group comes from molecular phylogenies that use fossils only as a source of node calibrations. However, node calibrations impose several constraints on tree topology and must necessarily make a priori assumptions about the placement of fossil taxa without testing their placement in the tree. Results: We present the first morphological dataset with extensive fossil sampling for Muroidea. By applying Bayesian morphological clocks with tip dating and process-based biogeographic models, we provide a novel hypothesis for muroid relationships and revised divergence times for the clade that incorporates uncertainty in the placement of all fossil species. Even under strong violation of the clock model, we found strong congruence between results for divergence times, providing a robust timeline for muroid diversification. This new timeline was used for biogeographic analyses, which revealed a dynamic scenario mostly explained by dispersal events between and within the Palearctic and North African regions. Conclusions: Our results provide important insights into the evolution of Muroidea rodents and clarify the evolutionary pathways of their main lineages. We exploited the advantage of tip dating Bayesian approaches in morphology-based datasets and provided a classification of the largest superfamily of mammals resulting from robust phylogenetic inference, inferring the biogeographical history, diversification, and divergence times of its major lineages.

There is an ongoing debate about the internal systematics of today’s group of hamsters (Cricetinae), following new insights that are gained based on molecular data. Regarding the closely related fossil cricetids, however, most studies deal with only a limited number of genera and statements about their possible relationships are rare. In this study, 41 fossil species from the Late Miocene to the Pliocene, belonging to seven extinct cricetine genera, Collimys, Rotundomys, Neocricetodon, Pseudocricetus, Cricetulodon, Apocricetus and Hattomys are analysed in a phylogenetic framework using traditional maximum parsimony and Bayesian inference approaches. Following thorough model testing, a relaxed-clock Bayesian inference analysis is performed under tip-dating to estimate divergence times simultaneously. Furthermore, so-called ‘rogue’ taxa are identified and excluded from the final trees to improve the informative value of the shown relationships. Based on these resulting trees, the fit of the topologies to the stratigraphy is assessed and the ancestral states of the characters are reconstructed under a parsimonious approach and stochastic character mapping. The overall topologies resulting from Bayesian and parsimonious approaches are largely congruent to each other and confirm the monophyly of most of the genera. Additionally, synapomorphies can be identified for each of these genera based on the ancestral state reconstructions. Only Cricetulodon turns out to be paraphyletic, while ‘Cricetulodon’ complicidens is a member of Neocricetodon. Lastly, this work makes a contribution to a debate that went on for decades, as the genus Kowalskia can be confirmed as junior synonym of Neocricetodon.

The family Muridae represents the largest, most diverse and successful of all groups of mammals. Here we infer the phylogenetic relationships and historical biogeography for the Iranian murid rodents, which consist in 17 species distributed in two subfamilies and six genera. Molecular dating analyses using a relaxed Bayesian molecular clock support the monophyly of Murinae and Gerbillinae and allow to set up a divergence date between them around 18.86 Ma (Million years ago). According to our results, murines may have originated approximately 13.49 Ma and the diversification of most of their evolutionary lineages may have taken place between 10–4 Ma, which is consistent with the fossil record. Our results provide strong support for the tribes Apodemyini and Rattini (Murinae) but the monophyly of the genus Meriones belonging to the Gerbillinae is questioned. Historical biogeographic analysis supports a Paleotropical origin for the Iranian murids, likely found in central and eastern Iran (Desert and Xeric Shrubland ecoregion). From there they dispersed to colonize the Afrotropical, Indomalayan and Palearctic realms. All in all, Iran seems to have acted as a corridor for faunal exchanges between the Afrotropic and Saharo-Arabian realms and the Indomalayan realm as well as between Central Asia and the Mediterranean regions.

Extinct organisms provide crucial information about the origin and time of origination of extant groups. The importance of morphological phylogenetics for rigorously dating the tree of life is now widely recognized and has been revitalized by methodological developments such as the application of tip-dating Bayesian approaches. Traditionally, molecular clocks have been node calibrated. However, node calibrations are often unsatisfactory because they do not allow the fossil age to inform about phylogenetic hypothesis. The introduction of tip calibrations allow fossil species to be included alongside their living relatives, and the absence of molecular sequence data for these taxa to be remedied by supplementing the sequence alignments for living taxa with phenotype character matrices for both living and fossil taxa. Therefore, only phylogenetic analyses that take into account morphological characters can incorporate both fossil and extant species. Herein we present an unprecedented morphological dataset for a vast group of glirid rodents, to which different phylogenetic methodologies have been applied. We have compared the tree topologies resulting from traditional parsimony and Bayesian phylogenetic approaches and calculate stratigraphic congruence indices for each. Bayesian tip-dated clock methods seem to outperform parsimony with our dataset. The strict consensus tree recovered by tip dating invalidates the classic classification and allows dates to be proposed for the divergence and origin of the different clades.

The modern era of analytical and quantitative palaeobiology has only just begun, integrating methods such as morphological and molecular phylogenetics and divergence time estimation, as well as phenotypic and molecular rates of evolution. Calibrating the tree of life to geological time is at the nexus of many disparate disciplines, from palaeontology to molecular systematics and from geochronology to comparative genomics. Creating an evolutionary time scale of the major events that shaped biodiversity is key to all of these fields and draws from each of them. Different methodological approaches and data employed in various disciplines have traditionally made collaborative research efforts difficult among these disciplines. However, the development of new methods is bridging the historical gap between fields, providing a holistic perspective on organismal evolutionary history, integrating all of the available evidence from living and fossil species. Because phylogenies with only extant taxa do not contain enough information to either calibrate the tree of life or fully infer macroevolutionary dynamics, phylogenies should preferably include both extant and extinct taxa, which can only be achieved through the inclusion of phenotypic data. This integrative phylogenetic approach provides ample and novel opportunities for evolutionary biologists to benefit from palaeontological data to help establish an evolutionary time scale and to test core macroevolutionary hypotheses about the drivers of biological diversification across various dimensions of organisms.