Phylogenomics confirm the monophyly of Guzmania (Bromeliaceae: Tillandsioideae) and provide evidence regarding alternative hybridization scenarios involving G. monostachia.

Plastome phylogenomics of the tribe Spermacoceae (Rubiaceae): taxonomic implications and a key to the genera

The first phylogenomic study of the tribe Spermacoceae based on plastome-scale data and expanded sampling of Neotropical taxa is presented, providing the most robust phylogenetic framework yet available for the tribe and establishing a foundation for future systematic, biogeographic, and evolutionary research.

Genome-based phylogeography of the red bamboo ratsnake Oreocryptophis porphyraceus (Serpentes: Colubridae).

Speciation is often considered as a prolonged, continuous and complex process shaped by interactions among multiple evolutionary forces, including both biotic and abiotic factors. Robust species delimitation is fundamental for understanding the basic biology and ecology of organisms and of course the implementation of effective conservation policies. The red bamboo ratsnake (Oreocryptophis porphyraceus) is a polytypic species in the family Colubridae widely distributed across Asia with a subspecific taxonomy has long been complex and controversial. Here, we integrated double-digest restriction-site associated DNA sequencing (ddRAD-Seq) with mitochondrial DNA (mtDNA) data to re-evaluate the subspecific taxonomy of this species primarily using samples from China and Vietnam. Phylogenetic relationships, population structure, tests of gene flow and species delimitation analyses consistently revealed that the species comprises at least four highly divergent, geographically structured lineages (five in the mtDNA phylogeny). Notably, these distinct evolutionary lineages are inconsistent with current taxonomic classifications. We propose a revised taxonomy that integrates genomic evidence with morphological data, and we discuss the distribution boundaries for each delineated species.

Phylogeography of the endangered ant species Atta robusta Borgmeier, 1939 (Formicidae: Myrmicinae): insights into genetic structure, demographic history, and conservation priorities

Atta robusta is a narrow endemic leaf-cutting ant restricted to restinga habitats along Brazil’s southeastern coast. Despite its conservation status, little is known about its evolutionary history and genetic structure. Here, we investigate patterns of genetic variation in A. robusta using mitochondrial (COI–IGS–tRNALeu–COII) and nuclear (EF1alpha copy one) DNA markers sampled across its known range. We assess genetic diversity and population structure and infer relationships among haplotypes using Bayesian phylogenetic analysis and haplotype network reconstruction. We detected moderate haplotype diversity (Hd = 0.7789 for mtDNA and phased Hd = 0.6737 for EF1alpha F1), significant but incomplete population differentiation (ΦST up to 0.61), and a weak to moderate pattern of isolation by distance. Bayesian analyses recovered geographically associated haplotypes with shallow genetic divergence, while nuclear marker exhibited low relative to mitochondrial data. The star-like haplotype network is compatible with multiple demographic scenarios, but neutrality tests did not provide evidence for departures from demographic equilibrium. Overall, our results indicate shallow genetic structure and incomplete spatial differentiation across the species range. These findings highlight the importance of preserving remnant restinga habitats and maintaining landscape connectivity to safeguard genetic diversity in A. robusta and other habitat-specialist ants.

Cryptic diversity, polyploidy, and intraspecific divergence in Erysimum (Brassicaceae) species endemic to the western Balkans.

BACKGROUND AND AIMS Several evolutionary drivers have been proposed to explain the exceptional species and genetic diversity of the Balkan flora, including the moderate impact of glaciations enabling long-term in situ persistence, ecological and topographic heterogeneity promoting vicariant differentiation, and polyploidy. Despite these shared drivers, plant lineages often show contrasting evolutionary histories, suggesting lineage-specific rather than broadly generalizable responses. The genus Erysimum, notable for its high endemism, karyological variation, recent and rapid speciation, and signatures of reticulate evolution, provides an excellent model for exploring this diversity of evolutionary trajectories and speciation drivers in the Balkans. METHODS Focusing on five Balkan endemics of the E. odoratum species complex sampled from 47 populations, we examined chromosomal and genome size variation and applied two complementary genomic approaches, target enrichment (Hyb-Seq) and RADseq, along with morphometric analyses. These datasets were used to circumscribe species, uncover intraspecific variation patterns, and assess the extent and evolutionary consequences of interspecific gene flow and polyploidy. KEY RESULTS Genetic and morphological evidence was largely congruent, clarifying species boundaries but also revealing cryptic diversity, leading to the recognition of eight entities. Most diversity was concentrated in the southern Dinarides, where we detected multiple cytotypes, an undescribed lineage, a polyphyletic species resulting from two independent autopolyploidization events, and allotetraploids arising in a contact zone. Geographic distance and biogeographic barriers across the mountainous Balkan landscape likely shaped patterns of divergence and promoted speciation. Discrepancies between chromosome numbers and genome size indicate dynamic chromosomal evolution. CONCLUSIONS Vicariant differentiation, auto- and allopolyploidy, genome size and chromosomal dynamics together account for the pronounced diversity of Erysimum in the Balkans, illustrating how speciation is driven within this biodiversity hotspot. Importantly, substantial evolutionary potential is retained within species, as the coexistence of multiple intraspecific genetic lineages and cytotypes can reinforce reproductive barriers and promote future diversification.

Mitogenomic and nuclear data redefine the phylogenetic position of Acrorbis, an enigmatic Neotropical planorbid lineage, with implications for Planorbidae systematics

The freshwater snail genus Acrorbis comprises minute rheophilic gastropods endemic to waterfalls and splash zones of the Upper Paraná Atlantic Forest in South America. Despite its distinctive morphology and long-standing taxonomic instability, its phylogenetic position has never been explicitly tested using molecular data. Acrorbis is currently classified within Helisomatini (Planorbidae: Planorbinae), although previous anatomical interpretations suggested alternative affinities. Here, we assembled and characterised the first complete mitochondrial genome of Acrorbis petricola and integrated mitogenomic and nuclear datasets to reassess the evolutionary placement of this enigmatic lineage and explore implications for planorbid systematics. The mitochondrial genome of A. petricola was 13,617 bp long and contained the typical set of 37 genes, with strong AT bias, multiple short overlaps, seven intergenic spacers, and candidate regulatory regions associated with strand-switch boundaries. Comparative analyses of available hygrophilan mitogenomes identified 15 distinct mitochondrial gene orders, revealing substantial structural conservatism within some clades and lineage-specific rearrangements in others. Acrorbis exhibited a unique derived gene order not detected in any other sampled taxon. Phylogenetic analyses based on mitochondrial datasets, concatenated nuclear 18S rRNA plus mitochondrial cox1 sequences, nuclear 28S rRNA , and combined mitogenomic and nuclear rRNA datasets consistently rejected the current placement of Acrorbis within Helisomatini. Instead, all analyses recovered Acrorbis outside Helisomatini, variously as sister to Ancylinae, Bulinidae, the remaining Planorbidae sensu lato (excluding Burnupiidae), or within a Neotropical clade including Drepanotrema and Antillorbis , depending on dataset composition. Our study provides the first genomic evidence for reassessing the systematic position of Acrorbis and demonstrates that its current tribal assignment is unsupported. Phylogenetic analyses consistently indicate that Acrorbis represents a distinct evolutionary lineage within Planorbidae sensu lato , while its mitochondrial architecture documents a distinctive history of structural evolution. These findings are consistent with the historical recognition of Acrorbis as a distinct tribal lineage (Acrorbini) and support renewed evaluation of suprageneric classification within Planorbidae, particularly the status of historical family-group names associated with the genus. More broadly, this study underscores the value of integrating genomic structure and multilocus phylogenetics to resolve problematic freshwater gastropod classifications.

Phylogeography and specific boundaries of Jatropha excisa (Euphorbiaceae) in the Chaco