Diversification of kangaroos and broader turnover among marsupial terrestrial herbivores coincided with emerging aridification then incipient grasslands.

Phylogenetic analysis of the New Guinean forest wallabies, Dorcopsis and Dorcopsulus reveals cryptic divergent lineages impacted by highland and lowland barriers.

The Hengduan Mountains (HDM), a biodiversity hotspot in Southwest China, harbour numerous endemic taxa whose diversification has been driven by the complex geological history of this region. This study investigates the diversification of the katydid genus Sichuana, endemic to the HDM, integrating mitochondrial genomics, morphology and biogeography. We sequenced complete mitochondrial genomes of all known geographic populations of Sichuana, revealing four major clades diverging during the Late Miocene (5.06-8.37 Ma). Orogeny-driven vicariance fragmented ancestral populations, while unstable barriers may facilitate mitochondrial introgression, as evidenced by paraphyletic lineages contrasting with distinct morphologies. We describe five new species (S. brevicerca sp. nov., S. fortidens sp. nov., S. qiuzhi sp. nov., S. luqiaoensis sp. nov. and S. pseudomagna sp. nov.) and two subspecies (S. pseudomagna pseudomagna subsp. nov. and S. pseudomagna borealis subsp. nov.), highlighting the taxonomic challenges posed by discordance between mitochondrial DNA-based phylogenies and morphological classifications. This study demonstrates that orogeny-driven vicariance dominates speciation in low-dispersal insects, but transient gene flow complicates species delimitation. Our findings advocate for integrative taxonomy in biodiversity hotspots and highlight the HDM as a model system for studying biogeographic complexity.

Late Miocene tectonic forcing of aridification in the Xunhua Basin, northeastern Tibetan Plateau

his study examines the biogeography, sexual systems, and genetic diversity of Leuenbergeria, a lineage of leafy cacti, which includes the national flower of the Dominican Republic, L. quisqueyana. Based on a time-calibrated nuclear phylogeny using 355 single-copy or low-copy loci, divergence times were estimated, and the evolutionary history of the group was reconstructed. The results indicate an origin in northern South America during the late Oligocene–early Miocene, with internal diversification primarily occurring during the Miocene. Colonization of the Greater Antilles occurred through an eastward dispersal event from Hispaniola in the mid–late Miocene, followed by secondary dispersal to Cuba. Individual heterozygosity estimates were low and showed no statistically significant relationship with insularity, sexual system, or lineage age, suggesting that genetic variation primarily reflects recent demographic processes. The combination of endemism, population fragmentation, and low genetic diversity highlights the vulnerability of several island species and provides an evolutionary and genetic framework relevant to their conservation.

The onshore southern Lake Albert Rift Basin in Uganda represents a geologically complex and hydrocarbon-prone segment of the western branch of the East African Rift System. This study integrates seismic, well and geochemical data, and 2D Basin and Petroleum Systems modeling to reconstruct the petroleum system of the basin. Results highlight spatial variations in source rock maturity and indicate a predominantly oil-prone character. Migration modeling reveals hydrocarbon expulsion and vertical migration into both the overlying Middle—late Miocene Kakara and underlying early Miocene Kisegi sandstone reservoirs, facilitated by fault-controlled pathways. The late Miocene—early Pliocene Oluka Formation proves to be an effective regional seal, supported by its low modeled porosity, while overpressure zones enhance migration and accumulation efficiency. Present-day thermal maturity profiles and porosity–depth relationships indicate favorable conditions for hydrocarbon generation, migration, and preservation. These findings redefine our understanding of petroleum system dynamics in the Albert Rift and underscore the exploration potential of underexplored structural and stratigraphic traps in the southern sector of this rift and analogous rift settings.

Late Miocene Asian monsoon intensification and turnover of Asian mammal communities

A Santacrucian record of Acarechimys minutus (Octodontoidea) from Laguna del Laja (Cura-Mallín Formation, Chile; late Early Miocene) and its biogeographic implications

Integrative phylogenetics and geography unveil Quaternary diversification and mitochondrial-nuclear discordance in Odorrana schmackeri sensu lato (Anura, Ranidae): Roles of Qinghai-Tibetan uplift, climate oscillations, and asymmetric gene flow.

Magnetic chronology of the late Miocene Wulangou red clay sequences in the northern Otindag Sandy Land

ABSTRACT The early-middle Miocene deposits of St Bathans, New Zealand, are renowned for their diverse and internationally important avian fossil biota that includes an abundance of fragmentary yet recognisable fossils from the crown bird clade Anseriformes (ducks and geese). We reviewed the taxonomic status of 11 isolated fossil bones previously referred to geese (Anserinae, Anseriformes) from St Bathans. Rigorous reassessment of these specimens using an expanded comparative morphological dataset demonstrated that four specimens can be assigned to the tadornine Miotadorna sanctibathansi and five are probably from a large anatid, potentially the purported anserine Notochen bannockburnensis. A second, slightly smaller, probable anserine is represented by one or possibly two bones, which we name as a new species, Meterchen luti gen. et sp. nov. We did not find any bones that showed a clear affinity with cereopsine anserines, thereby contradicting a previous hypothesis that cereopsines have a long history in Zealandia dating back to at least the early-middle Miocene. Our findings are consistent with current molecular divergence time estimates suggesting that the ancestors of the recently extinct cereopsine Cnemiornis arrived in Zealandia in the late Miocene. https://zoobank.org/urn:lsid:zoobank.org:pub

The suid assemblages from Europe experienced considerable turnover during the Vallesian (MN9-MN10, early Late Miocene), ultimately leading to a marked decline in diversity during the Turolian. To provide further insight into the timing and paleoecological context of this Vallesian turnover in the suid assemblages, here we revisit the taxonomic composition of the suids from the Late Miocene (9.8 Ma) fossil locality of Can Llobateres 1 (CLL1; Vallès-Penedès Basin, NE Iberian Peninsula), with emphasis on species other than the small tetraconodontine Parachleuastochoerus crusafonti (for which CLL1 is the type locality). Although CLL1 is one of the most thoroughly sampled Vallesian sites from Europe, a recent revision of the faunal list evinced that the occurrence of multiple large mammals is based on fossil remains that were described many decades ago or that have never been published, leading to potentially misleading or, at least, insufficiently substantiated attributions. According to published accounts, three additional suid species are recorded at CLL1, being much scarcer than Pa. crusafonti : the listriodontine Listriodon splendens , the suine Propotamochoerus palaeochoerus , and a large tetraconodontine variously assigned to Versoporcus steinheimensis or ‘ Parachleuastochoerus ’ valentini . Our revision of the available remains, including unpublished material recovered from the 1980s onward, confirms the presence of the two former species and the assignment of the large tetraconodontine to ‘ Pa. ’ valentini . On biochronological grounds, the association of these taxa is characteristic of the early Vallesian, with the record of L. splendens representing the last well-dated occurrence of this species. From a paleoenvironmental viewpoint, the suid assemblage from CLL1 is consistent with previous inferences indicating the presence of a densely forested and humid environment with more open habitats nearby.

Andrena is a species-rich genus of bees with a wide distribution, predominantly in the Holarctic. Here, we describe and illustrate a previously unknown species, Andrena (Labergeia) cenizophila Neff, Bossert & Zabinski n. sp., from southwestern Texas and central Coahuila, Mexico. Phylogenomic analyses recovered the new species as most closely related to Andrena (Labergeia) nahua Neff, a central Mexican species that was hitherto known only from the male sex. The discovery and examination of additional specimens of A. nahua allows us to describe and illustrate the previously unknown female, which shares diagnostic morphological features with the female of A. cenizophila n. sp. Based on these insights, we expand the diagnosis of Labergeia Neff to accommodate both species and discuss morphological affinities with their closest relatives in the subgenus Dactylandrena Viereck. Fossil-informed divergence time estimates indicates that Labergeia originated in the late Miocene, around 8 million years ago (5.37–11.82 mya), and that all known species of the subgenus, as well as its sister lineage Dactylandrena, are distributed in western and/or central North American. Lastly, we discuss the unusual foraging biology of A. cenizophila n. sp., which, based on observations and analyses of scopal pollen loads, is an oligolege of Leucophyllum frutescens (Berl.), I. M. Johnst. (Scrophulariaceae), a shrub commonly known as cenizo, Texas ranger, or Texas purple sage, among others. Interestingly, cenizo has a distinct floral phenology with comparatively short-termed mass blooms of not more than a week in duration, rendering it an unexpected choice for a specialist pollen collector. To our knowledge, A. cenizophila n. sp., is the only New World Andrena species that is oligolectic on plants of the family Scrophulariaceae.

Abstract Over the past 10 million years, coastal-marine settings along the Peruvian Margin have undergone profound geographic and oceanographic transformations, resulting in extensive changes in coastal-marine communities. While mollusk taxonomy research is slowly being integrated into ecosystem-wide analyses, which have historically centered on vertebrates, a long-term chronostratigraphically controlled analysis of molluscan diversity and compositional changes has not been undertaken for this region. We compiled a database covering 152 species, 97 genera, and 51 families of mollusk fossils from the Peruvian Margin (13–16°S) to assess long-term diversification patterns and faunal turnover from the late Miocene to the present. We identified two distinctive molluscan assemblages. The first, dating to the late Miocene (10–6 Ma), underwent a substantial shift during the Mio-Pliocene transition (6–4 Ma), culminating in a second assemblage more akin to modern counterparts. This shift resulted in an increase in diversity, with the younger assemblage (6–0 Ma) exhibiting greater genus richness than the former late Miocene assemblage. The turnover at 6–4 Ma was driven by peaks in bivalve origination (6–5 Ma) along with elevated extinction rates for gastropods (6–5 Ma) and bivalves (5–4 Ma). Ecological analyses revealed that no single ecological trait consistently changed during this interval, indicating that the turnover resulted from a broad reorganization of ecological strategies. We propose that the major molluscan turnover during the late Miocene–early Pliocene is associated with geomorphological changes related to the Andean uplift, the disappearance of semi-embayments, and a sea-level rise.

Although biostratigraphy and paleoecological studies are central to reconstructing paleodepositional environments and constraining source and reservoir rock distribution during petroleum exploration, detailed applications in offshore Niger Delta wells remain limited. This study analyzes the lithostratigraphy and foraminiferal assemblages of the FT-1 Well, offshore Niger Delta, over the 2,300–2,550 m interval to reconstruct the stratigraphic framework and paleoenvironmental history. Lithostratigraphic analysis reveals predominantly shaly facies, whereas foraminiferal biostratigraphy shows the dominance of benthic species (68.4%) over planktonic species (31.6%), a relationship that is diagnostic of outer–upper bathyal marine settings. The studied interval is assigned to the N18–N19 planktonic foraminiferal zones and to the NNDF 04–NNDF 06 benthic foraminiferal zones of the Neogene Niger Delta. The section is richly fossiliferous, containing abundant and diverse foraminiferal assemblages. The top of the N18–N19 interval is tentatively placed at 2,300 m based on the First Downhole Occurrence (FDO) of Globigerina nepenthes, while the base is constrained by the Last Downhole Occurrences (LDOs) of Neogloboquadrina dutertrei and Globorotalia tumida at 2,490 and 2,540 m, respectively. The NNDF 04 Zone extends from 2,300 to 2,430 m and is marked at its base by the occurrence of Cyclammina cf. minima; NNDF 05 spans 2,430–2,460 m, defined by the FDOs of C. cf. minima and Haplophragmoides narivaensis; NNDF 06 extends from 2,460 m to 2,550 m, the deepest analyzed sample, and is characterized by the continued occurrence of H. narivaensis. Paleoecological interpretation of the foraminiferal assemblages indicates mostly tropical–subtropical conditions with normal marine salinity, but includes cooler-water indicators such as Cyclammina cf. minima, Globocassidulina subglobosa, Uvigerina hispida, and Uvigerina auberiana, which are typical deep-water species. On the basis of the N18–N19 planktonic zonation, the sediments are interpreted to have been deposited during the Late Miocene–Early Pliocene. Collectively, these findings refine the stratigraphic framework and enhance understanding of the paleoenvironmental evolution of the Niger Delta’s offshore deposits, with implications for more accurate prediction of petroleum system elements.

ABSTRACT The Montbrook Fossil Site in Levy County, Florida, is a Late Miocene (6.0–5.6 Ma) fluvial deposit with a diverse turtle assemblage that includes exceptionally well-preserved musk turtles, genus Sternotherus. Sternotherus pugnatus n. sp. is described from eight partial to nearly complete shells, jaws, a maxilla, and hundreds of isolated postcranial bones. It is a small species with a low, narrow, and smooth carapace that is flat dorsomedially and acarinate except for along the posterior midline, lacks a lateral crest along the bridge peripherals, and has highly reduced to absent axillary and inguinal scutes. A cladistic analysis places S. pugnatus and its sister taxon Sternotherus bonevalleyensis within crown group Sternotherus and sister to the extant species Sternotherus peltifer and Sternotherus depressus. Many of the fossil shells exhibit healed injuries from microbial infections and predation attempts, including pockmarks, parallel scrapes, split carapaces, a broken plastral buttress, and punctures with embedded fish tooth tips, documenting previously unknown predator-prey interactions in early Sternotherus. Early Pleistocene fossils of Sternotherus that immediately post-date Pliocene sea level inundation of Peninsular Florida are also discussed and figured, as are Middle to Late Pleistocene musk turtle fossils including Sternotherus odoratus (dwarf and large forms) and Sternotherus minor. ZooBank Nomenclatural Act—https://zoobank.org/urn:lsid:zoobank.org:act:1D0F91CC-716D-4F0C-8994-D32341EED644

The stratigraphic evolution of low-latitude carbonate platforms, highly sensitive to sea-level changes, is often poorly constrained due to limited core data and discontinuous depositional records. This study elucidates the evolution of the Meiji Atoll, a representative low-latitude platform in the southern South China Sea (SCS), since the late Miocene, using the reef-penetrating core (Well NK1) from Nansha Island. By integrating facies analysis, sequence stratigraphy, and geochemical proxies, we identified two third-order sequences (SQ1 and SQ2), each comprising transgressive (TST) and highstand (HST) systems tracts. Geochemical data indicate that TSTs were associated with enhanced upwelling and nutrient availability, fostering algal productivity, while HSTs were marked by subaerial exposure. The overall retrogradational stacking pattern of the atoll reflects a dominant control by long-term sea-level rise, superimposed by eustatic fluctuations. Our findings confirm that eustatic sea-level variations were a primary factor controlling the stratigraphic architecture and development of Cenozoic low-latitude carbonate systems.

The index-species of calcareous nannoplankton in two cored wells, penetrating the Miocene rocks of the Alba Guyot, have been used to identify time intervals for deposition of the young (Pleistocene-to-modern, <1.8–0.2 Ma) Fe-Mn crust from Unit III in the complete section of the Magellan Seamounts Fe-Mn crusts, Late Miocene (>7–13 Ma) basanite tuff, tuffite sublayer (<5.6–7.0 Ma), as well as the ancient crust and buried nodules formed prior to the Early Miocene – Late Oligocene (>18–24 Ma). There have been discovered young Fe-Mn crust sublayers of contrasting composition and growth rate: early, enriched in Mn, Ni, Cu, Nb, and late, substantially ferruginous, with high REE, Y, Be, Sc, V, Zn, Rb, Cs, Sr, Zr, Hf, Mo, Sb, Pb, Th and U contents. Disregarding the duration of a probable break in the deposition of ore matter (Fe-Mn oxyhydroxides), the young crust with a Co-chronometry-based thickness of ~4 mm was formed over a period of ~2.3 Ma with an average growth rate from 1.6 mm/Ma in the early sublayer to 2.2 mm/Ma in the late sublayer. A young Fe-Mn crust 4–8 mm thick began to form on Miocene rocks 4.5 to 2.3 Myr, when the guyot surface was at depths below the oxygen minimum zone in the ocean water column (>600–700 m). A contrasting change in the composition of the late sublayer (a significant increase in Fe, REE, Y, V, Zn, Sr, Zr, Hf, Mo, Sb, Pb, Th and U contents) could have been caused by a 500000-year-old rapid subsidence of the guyot to depths similar to present-day (1250–1500 m at the plateau level). The average Co concentration (0.8–1.0 wt. %) in the young Fe-Mn crust on Miocene rocks is almost twice that of the bulk composition of thick (multilayered) crusts in other parts of the guyot. Relatively small-scale distribution of the young Fe-Mn crust, anomalously enriched in Co, will apparently have an insignificant impact on the increase in inferred ore reserves on the Alba Guyot for this strategically important metal.

Abstract Since the end of the Laramide Orogeny (~50 Ma), southwest Montana has experienced complex tectonic, climatic, volcanic, and mantle dynamic processes that have left an imprint on the landscape. Here, we examine the impact of post-orogenic and recent hotspot-related processes on the landscape by quantifying the Cenozoic exhumation history of the Madison and Gallatin Ranges, located on the northern flank of the Yellowstone hotspot (YSH) in southwest Montana. We apply the apatite (U-Th-Sm)/He (AHe) thermochronometer to Cretaceous and Paleogene intrusions from three transects to constrain the Cenozoic cooling history. We also present three new zircon U-Pb crystallization ages. AHe dates from 16 samples produced dates ranging from 67 ± 8.3 Ma to 6.2 ± 0.76 Ma. Most dates are between 45 and 20 Ma and younger than their crystallization age. Samples from the elevation transect with the largest relief display a positive relationship between AHe date and elevation, and thermal history modeling shows a phase of exhumation from ~30–23 Ma. AHe dates in the Madison Range young as they approach the Madison Fault, the range-bounding normal fault, and we ascribe most of the exhumation in the Madison Range to extension and tectonic exhumation due to footwall uplift. We interpret the ~30–23 Ma cooling to represent fault initiation and a phase of Oligocene extension that shows that post-orogenic extensional faulting and collapse propagated into the Laramide domain at that time. Late Miocene AHe dates near the fault represent a renewed phase of motion in the Miocene to recent, though our data lack the resolution to constrain the specific timing. Erosional exhumation due to YSH-driven regional uplift appears to be minimal.

ABSTRACT This study aims to unravel the petroleum system(s) of the Geisum area within Egypt's prolific Gulf of Suez rift basin through investigating the hydrocarbon potential of source rocks and genetic origin of petroleum plays. A total of 135 cutting samples were analyzed using organic geochemical procedures, including Rock‐Eval pyrolysis and vitrinite reflectance (%Ro), whereas 1D basin models were applied to simulate the basin's burial and thermal histories. Gas chromatography‐flame ionization detector (GC–FID), GC–mass spectrometry (GC–MS), and GC‐combustion–isotope ratio mass spectrometry (GC–C–IRMS) were conducted on 12 crude oils and six source rock extracts to assess bulk geochemical characteristics, biomarkers, and isotopic compositions of parent source rocks. The 1D‐modeling results along the NW–SW profile suggest that the Geisum area is a productive province, including Brown Limestone as the primary source (TR = 85%–95%), whereas Matulla/Wata contributed moderately (TR = 25%–44%), and Rudeis only expelled hydrocarbons in the southern compartment. Furthermore, heat flow (HF) rather than erosion predominantly controls thermal maturity, with peak generation occurring during the Late Miocene (7–5 Ma) in the northern and southern sectors. Structurally, the area is divided into three compartments due to Oligocene rifting, which influenced hydrocarbon migration pathways. The multivariate chemometric analysis reveals three genetically distinct oil families distributed across different oilfields in the Gulf of Suez. Family I, in the Geisum oilfield, likely derives from carbonate‐rich Sudr/Brown Limestone (high gammacerane, C 29 sterane dominance, depleted δ 1 3 C). Family II, from the same oilfield, is attributed to marine Matulla shales (moderate gammacerane, C 27 steranes, similar δ 1 3 C). Family III, from the Tawila oilfield, appears sourced from mixed marine/lacustrine Rudeis sediments (low gammacerane, C 28 steranes, enriched δ 1 3 C).