Islands harbour unique biodiversity, and depending on their geological origin, they have fundamentally different colonisation histories: continental islands may contain relict faunas shaped by vicariance and sporadic gene flow, whereas oceanic islands must have been colonised across open seas, often through long-distance dispersal events. Mercuria is a species-rich genus of freshwater gastropods (33 extant nominal species) widely distributed across the western Palaearctic, including both continental and insular regions, making it a promising candidate for investigating the dispersal modes and colonisation routes of freshwater invertebrates to Atlantic and Mediterranean islands. Yet, species identities, taxonomy and phylogenetic relationships within the genus remain poorly resolved. Here, we present a multilocus phylogeny based on three genes for 216 individuals representing 14 species, with sampling spanning continental populations and insular lineages from the Madeira, Canary, Balearic and Maltese islands, as well as Great Britain. Our results reveal an unrecognised island endemic species in Gran Canaria (Canary Islands), confirm that Madeira harbours the widespread M. tachoensis rather than an endemic species, and provide the first genetic evidence of M. similis in Majorca (Balearic Islands). Biogeographic reconstructions suggest that insular populations originated through multiple passive dispersal events from continental Europe and North Africa, as divergence times (Late Miocene onwards) postdate the island formation. Phylogeographic analyses of widespread species further showed limited dispersal and a single colonisation of Minorca by M. balearica, whereas M. similis and M. tachoensis exhibited broader connectivity. Collectively, these findings reveal complex, lineage-specific colonisation dynamics in Mercuria, highlighting unrecognised diversity and conservation needs.
The Trichiuroidea, commonly known as snake mackerels and cutlassfishes, constitute an important component of marine pelagic and demersal fish assemblages. Members of this superfamily exhibit a wide spectrum of body shapes from fusiform to elongate and are currently classified into two families (Gempylidae and Trichiuridae), comprising 26 genera and 73 species. In this study, a new and comprehensive multiple nuclear gene dataset of the Trichiuroidea and their allies was constructed to evaluate the monophyly of trichiuroid families, relationships within the superfamily and the monophyly of constituent genera. Our phylogenetic analyses support the monophyly of the Trichiuroidea and Trichiuridae, but also support the non-monophyly of Gempylidae with respect to Lepidocybium. The monotypic genus Lepidocybium has been an independent lineage for c.a. 62.1-65.1 million years. To adhere the principle of phylogenetic classification, we propose a new family Lepidocybiidae (elevated from formal subfamily of Gempylidae). Lepidocybiidae can be distinguished from Gempylidae and Trichiuridae by a combination of characters, including median caudal keels flanked by two smaller keels, a strongly tortuous lateral line, inward-curving conical teeth, a pale porous reticulation around the scales, fewer vertebrae (31-32) and a relatively long, posteriorly expanded, leaf-like dorsal postcleithrum. In addition, Lepidocybiidae differ from Trichiuridae in possessing finlets and two pairs of nostrils rather than a single pair. Within the Trichiuroidea, all currently recognized genera are recovered as monophyletic except Trichiurus.
ABSTRACT Lophotrochozoa is one of the three major bilaterian groups comprising more than half of the bilaterian phyla. Lophotrochozoa includes among others Mollusca, Annelida, Platyhelminthes and Rotifera. Despite representing such a large proportion of animal diversity, they are historically understudied and genomic resources have been scarce. However, the last years have seen a strong increase of genomic resources due to the initiatives associated with the Earth Biogenome Project. Hence, herein I will review the progress made with respect to the available genomic resources for Lophotrochozoa and its phylogeny based on genome‐scale data. With several hundreds of chromosome‐level genomes available for Lophotrochozoa, tremendous progress has been achieved. However, tissue availability in relation to the genome size remains a major challenge and genomic information for small‐sized lophotrochozoan taxa like Gnathostomulida and Entoprocta are still missing on a large scale. Hence, a major challenge remains to obtain enough high‐quality DNA despite recent progresses in whole‐genome amplification methods. Summarizing recent phylogenomic studies showed that monophyletic Chaetognathifera is sister to the remaining Lophotrochozoa, known as Platytrochozoa. Within Platytrochozoa, Rouphozoa, Entoprocta + Cycliophora, Lophophorata and Bryozoa + Phoronida can be recognized as monophyletic, but other relationships are contentious. Moreover, to date, no phylogenomic study has sampled all lophotrochozoan phyla. Reviewing macrosyntenic studies and patterns across Lophotrochozoa reveals that its potential as a phylogenetic marker might be much more limited than expected. The analyses show very high degrees of convergent evolution, in part due to massive fusion events. Hence, convergent evolution of fusion‐with‐mixing events might be more rampant than assumed at present.
Spider crabs of the genus Eurynome have complex taxonomic, phylogenetic, and biogeographic histories worldwide. Using newly generated molecular data, including the characterization of complete mitochondrial genomes, we addressed several unresolved questions surrounding the genus and its two Atlantic-Mediterranean representatives, the type species Eurynome aspera and its sympatric Eurynome spinosa. DNA-barcoding and reverse taxonomy demonstrated conspecificity between Atlantic and Mediterranean samples, confirmed the occurrence of E. spinosa in the Mediterranean Sea sensu stricto, and contradicted most diagnostic characters previously proposed in the literature. In their place, a set of 10 molecularly validated morphological traits, regardless of sex and developmental stage, was proposed and accompanied by high-resolution imagery. The DNA-assayed material was then used to investigate the phylogenetic position of Eurynome through various inferences (multilocus and mitochondrial genome trees, and mitochondrial gene orders), which suggested that these taxa form a distinct, early-diverging clade, for which the family Eurynomidae Neumann, 1878 is resurrected here. This was also supported by high similarity with the ancestral Brachyura mitochondrial gene order and strong dissimilarities with other majoid ones. Although several questions remain open, the present results resolve debates on two pseudo-cryptic species, elevate Eurynome to one of the most molecularly characterized majoid genera, and lay a solid foundation for proceeding with the study of allied taxa and the entire superfamily through modern integrative approaches.
ABSTRACT The psammophilous colubrid genus Lytorhynchus is widely distributed in the deserts of the Saharo‐Sindian region and adjacent areas. The taxonomy of the genus and the number of recognised species have remained unstable since the last taxonomic revision in 1970, with differing views on the taxonomic status of L. gaddi and L. kennedyi . As no comprehensive study has included all species in a phylogenetic context, we present here the first phylogenetic and biogeographical hypothesis for all but one recognised species ( L. gasperetti ) based on three mitochondrial and four nuclear genetic markers. Our time‐calibrated phylogeny revealed that the genus originated in the late Oligocene–early Miocene, with an ancestral geographic range within the present‐day Irano‐Turanian region. Most diversification events occurred during the Miocene and were likely driven by tectonic movements, mountain uplifts, and increasing aridification across the region. Our results are largely congruent with the traditional taxonomic concept of the genus and its recognised species. Phylogenetic analyses recovered L. gaddi and L. kennedyi as distinct lineages separate from L. diadema , with which they were previously treated as synonyms, subspecies or colour variants. However, this distinction is not fully reflected in all the nuclear loci or in species delimitation analyses, possibly due to limited sampling and incomplete lineage sorting. Accordingly, species‐level status for both taxa is provisionally proposed pending further investigation.
ABSTRACT Linnaean and Wallacean shortfalls remain pervasive even among common and widespread Mediterranean taxa, limiting our understanding of evolutionary history and species boundaries. The Ocellated Skink Chalcides ocellatus complex illustrates this issue, with disputed subspecific taxonomy and deep mitochondrial divergences across North Africa and the Middle East. We combined mitochondrial (cytochrome b; 189 individuals) and nuclear markers (four loci; 2339 bp concatenated; 44 individuals) to test whether mitochondrial lineages reflect independently evolving units and to assess gene flow across contact zones. Both nuclear and mitochondrial DNA analyses recovered four clades and haplogroups, respectively. While deeper relationships among these lineages remained unresolved in both phylogenies precluding potential topological comparisons, geographical comparisons revealed marked cytonuclear discordances. In the Maghreb, the mitochondrial contact zone between Western and Eastern haplogroups occurs in Kabylia (eastern Algeria), whereas the nuclear transition between corresponding subtypicus and tiligugu subspecies lies ~650 km further west near the Morocco—Algeria border. Most individuals across this region carry Western mtDNA haplotypes within an ‘eastern’ tiligugu nuclear background, indicating extensive mitochondrial introgression. Similar discordance was also observed in Egypt between C. humilis and C. o. ocellatus . Nuclear data supports the evolutionary distinctiveness of the four main lineages but provide limited resolution regarding their deeper relationships. The large geographic displacement between mitochondrial and nuclear suture zones strongly suggests historical introgression rather than incomplete lineage sorting. Our results confirm the reproductive isolation of C. humilis , highlight the independence of both Maghreb ( subtypicus and tiligugu ) lineages, and demonstrate that mtDNA alone is unreliable for delimiting taxa in this complex, calling for genome‐wide reassessment of species boundaries.
Since their discovery, the question of the phylogenetic position of Microcerberidae within Isopoda has been widely debated. Initially perceived as close relatives of the Anthuridae, the debate has shifted towards considering them either as a sister group of Asellota or positioned within the Asellota in their own right. In this study, we used sequence data for eight slow-evolving nuclear genes in 37 isopod taxa to test for the hypothesis that Microcerberidae were Asellota and, as such, should not be regarded as an independent suborder within the Isopoda. We also evaluated the earlier hypothesis of a sister relationship between the Anthuridae and Microcerberidae. Altogether, our results provide strong evidence in favour of a clade including the Microcerberidae and the Aselloidea, which supports the invalidation of the suborder Microcerberidea.
Carabidae (ground beetles), the third largest family within Coleoptera, exhibit remarkable diversity extensively documented in natural history collections, making them an ideal group for museomic studies. This work focuses on subterranean ground beetles of the tribes Sphodrini and Trechini and aims to clarify the phylogenetic position of key taxa that are extremely difficult to sample in the wild due to their rarity and inaccessibility. We particularly examined two highly troglomorphic species, Ifridytes mateui Deuve & Qu & eacute;innec, 1994 and Subilsia senenti Espa & ntilde;ol, 1967, whose unique morphology has long obscured their systematic placement. Two datasets were assembled: (i) MTG, comprising 13 mitochondrial protein-coding genes and two rRNA genes from complete mitogenomes; and (ii) SEQ, including mitochondrial COX1 and 16S and nuclear 18S and 28S. Divergence times were estimated under a Bayesian relaxed-clock model in BEAST. All historical specimens were successfully extracted, amplified and sequenced, validating the museomic approach for reconstructing evolutionary histories of rare taxa. Ifridytes, previously enigmatic, is strongly associated with Sphodrini and likely related to Sphodrina. Conversely, Subilsia nests within epigean Trechus, supporting the hypothesis that extreme troglomorphic adaptations evolved independently and convergently within Trechini. This study demonstrates the power of museomics to resolve long-standing systematic questions and provides new insights into the evolutionary history of subterranean Carabidae.
Clarifying formation processes and dispersal history of given taxon provides important insights into understanding the origins and persistence of regional biodiversity. Here, we investigated the phylogeny, divergence times, genetic diversity, population structure, and demographic history of Uropsilus populations distributed across the Mts. Qinling-Dabashan area using two mitochondrial and three nuclear loci. The results indicated that Uropsilus populations in the Mts. Qinling-Dabashan area are composed of U. funiushanensis (east) and U. sp. 5 (west), with their most recent common ancestors dated back to 2.18 Ma (95% CI: 2.00-2.67 Ma). The populations exhibit pronounced east-west genetic differentiation, with additional north-south structuring observed within each species. During the Last Glacial Maximum, both U. funiushanensis and U. sp. 5 experienced population expansion, and the Hanjiang River posed a minimal barrier to north-south gene flow, whereas subsequent Holocene warming led to increased isolation. Overall, the Mts. Qinling-Dabashan have consistently provided suitable habitats, maintaining the genetic diversity of U. funiushanensis and U. sp. 5. These findings were expected to provide new insights into the speciation, historical dispersal, and the maintenance of genetic diversity of Uropsilus in the Mts. Qinling-Dabashan area of China.
As one of the most polymorphic and highly derived ciliate groups, the order Urostylida is a large benthic ciliate group, in which their phylogenetic relationships and geographical distribution remain unclear due to the lack of sufficient data, particularly those difficult to obtain by traditional approach. By using high-throughput sequencing of the SSU-rRNA gene V4 region, we obtained 115 OTUs of the subclass Stichotrichia, including 56 OTUs of the order Urostylida, from sediment samples from intertidal flat through continental shelf to deep-sea habitats including hydrothermal vent, seamount, abyssal plain and Trench with water depth maxing to 6684 m. Compared to the background inferred from phylogenetic analyses based on full-length SSU-rRNA gene sequences with detailed morphological identification, the efficacy of using short NGS amplicons in phylogenetic inference has been verified by analysing the 'clade placement' and 'bipartition support' values. For several taxa in the order Urostylida, our phylogenetic analyses based on short NGS amplicons indicate new clues with higher sensitivity to clarify the phylogenetic relationships. And the present work also provides evidence for marine-freshwater transitions during the diversification of hypotrichous ciliates. Environment sequences from broader habitats have increased the density of sampling and provided new perspective to understand the phylogenetic and geographical distribution of the benthic ciliate.
The Punctidae is a group of small to minute land snails with their centre of diversity in Australia and New Zealand. We present a comprehensive molecular phylogeny of Australian punctids based on mitochondrial (COI, 16S) and nuclear (ELAVI8, ITS2) markers, including 27 of the 32 mainland and Tasmanian species, as well as representative samples from Lord Howe Island, Norfolk Island, Macquarie Island and New Zealand. Measurements of shell dimensions of all sequenced specimens were analysed using the Kruskal-Wallis rank-sum test to assess morphological support for branching patterns. The Australian punctids comprise a large unresolved radiation made up mostly of mainland species that diverged around 5.5 Ma, with more basal groups comprising taxa from Tasmania, New Zealand, Macquarie Island, Lord Howe Island and Norfolk Island. To better reflect the pattern of rapid diversification of punctids on the Australian mainland, and supported by morphological data, we treat the genera Gratilaoma, Iotula, Laomavix, Miselaoma, Pseudiotula, Tescilaoma, Trocholaoma and Westralaoma as junior synonyms of Paralaoma. We demonstrate that Pasmaditta jungermanniae, Pedicamista sp. 'Bull Hill' and Trocholaoma spiceri are part of Cystopeltidae rather than Punctidae, and that the Norfolk Island charopids Norfolcioconcha, Penescosta, Cryptocharopa and Frustropa belong to Punctidae. Based on molecular data and examination of types, we treat Paralaoma annabelli as a junior synonym of Paralaoma mucoides, Westralaoma experta as a junior synonym of Paralaoma morti, and Westralaoma expicta as a junior synonym of Paralaoma servilis.
The Otocolobus manul, a small felid endemic to the high-altitude Qinghai-Tibet Plateau, lacks a high-quality chromosome-level genome, hindering study of its evolutionary adaptations. This study aimed to construct such a genome and investigate its genetic basis for high-altitude adaptation. We generated a de novo chromosome-scale assembly using an integrated approach of PacBio HiFi long-reads, Illumina short-reads, and Hi-C scaffolding. The resulting 2.55 Gb genome was anchored to 19 chromosomes (contig N50 = 96.32 Mb) and contained 22,699 protein-coding genes. Comparative genomic analysis across felids revealed 13 expanded gene families in O. manul, functionally enriched in processes like glycolysis/gluconeogenesis and the HIF1 signalling pathway. Phylogenetic analysis placed O. manul as sister to Prionailurus, with an estimated divergence time of 6.10-7.04 million years ago, and identified positive selection signals linked to adaptation. Furthermore, we found that the nuclear genome supports a sister relationship between O. manul and Prionailurus (they are closely related species), while the mitochondrial genome suggests a closer relationship with Felis. This significant mito-nuclear phylogenetic discordance is primarily attributed to incomplete lineage sorting (ILS). This de novo chromosome-level genome assembly of O. manul provides a crucial resource for evolutionary and conservation studies. The findings specifically highlight significant genetic enrichments in hypoxia-responsive pathways, suggesting its molecular adaptation to the extreme plateau environment.
We herein constructed a phylogeny of Lepidoptera synthesizing multiple information types, a phylogenomics backbone, a multigene supermatrix with species-comprehensive DNA barcodes, and topological information from a compiled database of standardized machine-readable trees from over 100 previous studies. We then applied the new phylogenetic synthesis as a profiling framework for a large DNA barcode dataset of caterpillars from a tree diversity experiment. The synthesis phylogeny comprised 11,001 species. Phylogenetic information content was taxonomically skewed towards butterflies (i.e., Nymphalidae, Papilionidae and Pieridae), and parts of Macroheterocera (Geometridae, Sphingidae, Saturniidae and Bombycidae), while undersampling of Lepidoptera species diversity was present in Erebidae, Noctuidae, Gelechioidea and Pyraloidea. Caterpillar Phylogenetic Diversity (PD) increased with tree richness in the diversity experiment regardless of processing choices in calculating caterpillar PD, including whether calculated on plot OTU alone, plot OTU placed onto a simple reference phylogeny or plot OTU placed to the comprehensive reference phylogeny. Stronger correlations between tree diversity and uncorrected Faith's PD of caterpillars were observed where OTU were placed onto the full reference tree, and where long branch OTU were removed prior to PD calculation, though no significant differences in the strength of the tree diversity effect across context and processing choice were observed for standardized PD. In calculation of plot-level PD, focus should remain on community sample size, with the results herein supporting the use of any available reference phylogeny as context, though correspondence of PD indices to environmental gradients might be stronger where plot OTU can be placed to a comprehensive reference phylogeny. The phylogeny presented herein enables inference of varied evolutionary information for Lepidoptera DNA barcode sets.
Subfamily Leuciscinae, the largest freshwater fish group of the western Palearctic region, has been widely studied, including the phylogenetic relationships between its species and genera. However, until now, one genus completely escaped attention in this regard. Even though several works hypothesised about its evolutionary relationships based on its scarce morphological data, they did not succeed in resolving this puzzle, and their assumptions were often contradictory. Our study aimed to bring insight into the phylogenetic origin and relationships of the enigmatic Caucasian genus Leucalburnus based on the most taxon-dense, multilocus molecular analyses of the subfamily Leuciscinae so far. Moreover, a time-calibrated phylogenetic reconstruction was performed in order to put the emergence of the Leucalburnus lineage in a timeframe. In our analyses, Leucalburnus was consistently recovered as a member of the Alburnus clade, which further comprises Alburnus, Leucaspius and Anaecypris, adding thus one more genus to the clade and providing more evidence of non-monophyly of the genus Alburnus.
Nuclear variation and phylogeography of the chromosomally highly polymorphic common shrew (Sorex araneus) represent a subject of considerable interest for understanding microevolutionary processes in wide-ranging mammals. In the present study, we addressed this issue using SNP data generated via the ddRADseq approach and based on extensive geographic sampling. Our results are consistent with the hypothesis of a recent range expansion from a refugium located in the Balkan-Danubian region, followed by subsequent colonization of Eastern Europe and, later, Siberia. This scenario had previously been proposed on the basis of mitochondrial DNA data. On the contrary, genetic relatedness of shrews from southern Karelia and central Siberia, as suggested previously from mtDNA variation, is not supported by our SNP dataset. Nuclear data reveal substantial gene flow across the boundaries between chromosomal races and racial groups.
Effective species conservation requires accurate identification of target taxa; however, the large intraspecific variation and strong phenotypic plasticity of shell morphology in freshwater mussels (Bivalvia: Unionidae) exacerbate taxonomic uncertainties, thereby complicating species delineation. Based on extensive geographic sampling, we conducted an integrative taxonomic revision and phylogenetic reconstruction of the freshwater mussel genus Lanceolaria by integrating shell morphology, geometric morphometrics, sequence data from multiple gene loci (COI, 16S rRNA, 18S rRNA and 28S rRNA) and mitogenome datasets. Molecular species delimitation methods and Fourier morphometric analysis confirmed two new species: Lanceolaria danzhouensis sp. nov., distributed in southern China and Vietnam and closely related to Lanceolaria grayii; and Lanceolaria helianthoides sp. nov., from Guangdong Province, China, which is closely related to Lanceolaria lanceolata. Additionally, we recognized Lanceolaria cylindrica syn. nov., Lanceolaria eucylindrica syn. nov. and Lanceolaria yueyingae syn. nov. as junior synonyms of Lanceolaria grayii, and the species exhibited extremely strong environmental adaptability and phenotypic plasticity. We first sequenced the mitochondrial genomes of five species within the genus. Based on multilocus and mitogenomic phylogenetic analyses, our results elucidated intrageneric relationships and revealed three major clades. Overall, we clarified the classification of the genus Lanceolaria, resolved long-standing taxonomic disputes, evaluated its species diversity and provided a reliable phylogenetic and taxonomic framework for this genus.
The pikas of the subgenus Alienauroa were discovered merely 25 years ago, with the principal diversity of this group described only in 2017. This study integrates genomic, morphological, and distributional data from all specimens collected to date to advance the understanding of phylogeny, taxonomy, and distribution within these pika species. Our analyses delineate four distinct species: O. syrinx, O. sacraria, O. huanglongensis, and O. flatcalvariam. The entire group is restricted to a limited geographic area situated between the Huanghe and Yangtze rivers. All species exhibit strict ecological association with dark coniferous forests. Two sister species, O. syrinx and O. sacraria, display disjunct distributions and significant genetic divergence, indicative of relict range fragmentation. In contrast, the second sister pair, O. huanglongensis and O. flatcalvariam, exhibit restricted distributions and lower levels of genetic variation. The species generally demonstrate allopatric distribution, with the exception of O. syrinx and O. sacraria in the Qinling and Dabashan mountains, where they exhibit sympatry.
Recent integrative taxonomic revisions of the amphiboreal nudibranch Diaphoreolis viridis (Forbes, 1840) suggest that it represents a complex of cryptic or pseudocryptic species. However, species delimitation within trans-Arctic taxa remains challenging due to the reliance on potentially variable morphological traits (such as coloration) and the limitations of using mtDNA data alone. Therefore, the taxonomic status of several North Pacific populations traditionally attributed to the Diaphoreolis viridis complex (Diaphoreolis midori (Martynov, Sanamyan & Korshunova, 2015), Diaphoreolis viridis emeraldi Korshunova, Fletcher, Bakken & Martynov, 2023, and the nominal form) requires rigorous re-evaluation using integrative approaches. The aim of this study is to clarify the identity of chromatic variants of D. viridis across its broad Pacific distribution and to assess the genetic connectivity of its distant populations. By combining detailed morphological examination with mtDNA genotyping and sequencing of nuclear ribosomal markers across a wide geographic range of the complex, this study provides a robust assessment of species boundaries within Diaphoreolis viridis and contributes to a broader understanding of the challenges and solutions in trans-Arctic nudibranch taxonomy. The phylogeographic analysis included a TCS-based network analysis, an analysis of molecular variance (AMOVA) and divergence time estimations. The results demonstrate the conspecificity of D. v. emeraldi and D. midori, as well as the conspecificity of the entire complex under the name D. viridis due to the absence of significant morphological and molecular differences. We also identified previously undescribed species from the Kuril Islands, Diaphoreolis shinkaii sp.nov., which differs markedly from other Diaphoreolis species in its molecular, morphological, and bathymetric characteristics.
The Amazon and Atlantic forests harbour immense biodiversity shaped by complex evolutionary history with diverse processes leading to species build-up. We investigated the Cinereous Antshrike species complex (Thamnomanes caesius and T. schistogynus) to disentangle the relative contributions of riverine barriers and historical climatic fluctuations to diversification, using large specimen sampling across their entire distribution and a multilocus dataset. Our results revealed hidden genetic diversity, with 13 geographically structured phylogroups largely concordant with Amazonian interfluves and areas of endemism. Species delimitation analyses supported eight of these lineages as independently evolving units, unveiling cryptic diversity within T. caesius. Divergence time estimates indicate that diversification took place during the Pliocene to Late Pleistocene, with signatures of demographic expansion consistent with climate-driven range dynamics. Our findings underscore a strong association between phylogroups and major river systems, revealing their role as primary drivers of lineage diversification, later modulated by demographic shifts associated with climatic oscillations. Our findings highlight an interplay between geomorphological and climatic factors in shaping avian diversity across the Amazon basin, while also pointing to underestimated taxonomic richness within the Thamnomanes caesius/schistogynus species complex.
Micoureus is the most species-rich subgenus within the genus Marmosa. Conflicting arrangements regarding the number of species comprising this subgenus have been proposed and the validity of M. budini has been debated. Here, we used an approach integrating genetic and morphological data were conducted to reanalyze the 'rapposa' group, investigate its biogeographic context, and test the status of M. budini as a distinct species of the M. rapposa complex. One mitochondrial and one nuclear marker were sequenced to recover species trees; divergence data and population aspects were inferred from mitochondrial data. Museum specimens were examined, including holotypes. The biogeographic data suggest the diversification in the 'rapposa' group to be associated with tectonism in the Andes and the Pebas System. Genetic analysis and external and craniodental morphology differences corroborate the species status of M. budini, with new record for Rond & ocirc;nia, Brazil, and M. rapposa would remain restricted to Peru. Marmosa rutteri exhibits intrapopulation variations driven by habitat fragmentation in the Pleistocene cycles and fluvial formations of the Amazon, and the separation in relation to M. budini coincides with climatic oscillations of the Late Quaternary and the Ucayali River.
