Late Middle Miocene Research Articles

Evolution of a Miocene canyon and its carbonate fill in the pre-evaporitic eastern Mediterranean

Extensive canyons, excavated into the margins of the Levant Basin during the Oligocene–Miocene, are interesting case-studies for canyon fills in carbonate settings. The carbonate Pattish Formation, developed along the margins of the pre-evaporitic Messinian Beer Sheva Canyon in Israel, was investigated using both onshore seismic imaging and field data. The canyon has three main seismic facies of fill (1) Subparallel reflections mimicking the canyon´s morphology; (2) chaotic reflections overlying the subparallel ones, and (3) sigmoidal reflections, locally with sharp edges at the canyon margins. The first seismic facies corresponds to the pelagic marls of the Bet Eshel Formation. The other two seismic facies are, respectively, equivalent to bioclastic calcarenite clinobeds with slumps and channels, and to coral–stromatolite reefs and reef slopes of the Pattish Formation observed at outcrop. There were three phases of canyon development: (1) slope incision and headward erosion due to tectonic uplift and eustatic sea-level fall during the Early Oligocene, and large slope failure during the latest Middle Miocene; (2) platform incision and connection with a fluvial system in the Late Miocene related to falling sea level and tectonic uplift; and (3) canyon filling first by pelagic marls at the centre of the canyon, followed by calcarenite clinobeds at the canyon flanks formed by gravity flows. Finally, carbonate production at the margins of the canyon resulted in reefs and associated slopes prograding towards the canyon axis. The late canyon filling phase ended with the deposition of evaporites during the Messinian Salinity Crisis.

Phylogenetic analysis of Middle-Late Miocene apes

Despite intensive study, many aspects of the evolutionary history of great apes and humans (Hominidae) are not well understood. In particular, the phylogenetic relationships of many fossil taxa remain poorly resolved. This study aims to provide an updated hypothesis of phylogenetic relationships for Middle-Late Miocene fossil apes, focusing on those taxa typically considered to be great apes. The character matrix compiled here samples 274 characters from the skull, dentition, and postcranium. Multiple iterations were performed to examine the effects of ingroup taxon selection, outgroup constraints, treatment of continuous data, character partitions (craniodental, postcranial), and missing data. Parsimony and Bayesian methods were used to infer phylogenetic relationships. Most European hominoids (Hispanopithecus, Rudapithecus, Dryopithecus, Pierolapithecus) are recovered as stem hominids, not more closely related to orangutans or to African apes and humans (Homininae), whereas Ouranopithecus, Graecopithecus, and Nakalipithecus are inferred to be members of the hominine clade. Asian fossil hominoids, with the exception of Lufengpithecus hudienensis, are recovered as part of the orangutan clade (Ponginae). Results suggest that Kenyapithecus and Griphopithecus are possible stem hominids, whereas Equatorius and Nacholapithecus are consistently recovered as stem hominoids. Oreopithecus and Samburupithecus are not recovered as hominids. Results of Bayesian analyses differ from those of parsimony analyses. Craniodental and postcranial character partitions are incongruent in the placement of hylobatids, which is interpreted as evidence that hylobatids and hominids independently evolved adaptations to suspensory positional behaviors. An understanding of phylogenetic relationships is necessary to address many of the questions asked in paleoanthropology. Thus, the updated hypothesis of phylogenetic relationships presented here can be used to gain a better understanding of important morphological transitions that took place during hominid evolution, ancestral morphotypes at key nodes, and the biogeography of the clade.

Caught in travertine: computed tomography reveals the youngest record of Amphicyon giganteus from the travertine deposits of Karacalar (late middle Miocene, central Anatolia, Turkey)

A computed tomography scan of a travertine slab from the Karacalar Silver Travertine Quarry (Afyonkarahisar Province, Turkey) revealed the presence of an encased partial cranium, partial mandible and three vertebrae. 3D reconstruction of the fossil helped identifying it as Amphicyon giganteus. As the travertine caps a section correlated to MN7/8, the specimen represents the youngest record of Amphicyon giganteus, the known range previously being limited to MN4 – MN6. This young age is in line with the more advanced morphology of the lower molars.

A re-appraisal of the middle-late Miocene fossil decapod crustaceans of the ‘Faluns’ (Anjou-Touraine, France)

The access to a new collection of decapod crustaceans collected from the middle-late Miocene ‘Faluns’, and examination of new specimens available, have allowed to expand the previous compilations by Couffon (1908) and Ossó & Gagnaison (2019), elevating to nineteen the species reported, representatives of seventeen genera and fourteen families. Squat lobsters and parthenopid crabs are reported for the first time in the Atlantic Miocene of France. The expected presence of Xantho moldavicus (Yanakevich, 1977) and Lobocarcinus sismondai (von Meyer, 1843), hitherto known only by chelae, is confirmed herein. The status of Haydnella pulchellus (A. Milne-Edwards, 1864) is discussed. Moreover, the ventral features of Necronectes michelini (A. Milne-Edwards, 1861) are described for the first time. This decapod assemblage presents clear affinity with coeval decapod faunas from the Mediterranean and Paratethys realm, as evidenced by the presence of identical species such as Liocarcinus kuehni (Bachmayer, 1953) or Pilumnus mediterraneus (Lőrenthey, 1897), which is by far, the most common decapod in the ‘Faluns’ outcrops. Several different chelae and carapace remains are left in open nomenclature.

Cenozoic multi-stage deformation of the Qilian Shan orogenic belt, northern Tibetan Plateau: Insights from a detrital zircon provenance study of an Oligocene-Miocene intermontane basin sedimentary succession

• Mesozoic sediments within the Qilian Shan orogenic belt transitioned from a “sink” to a “source” before the Oligocene . • Obvious provenance change occurred at ∼22 Ma in the Subei Basin, an intermontane basin within the Qilian Shan orogenic belt. • The southern Qilian Shan orogenic belt underwent deformation in the earliest Miocene and middle-late Miocene. • Recycled Oligocene sediments inside the basin became the main provenance at ∼9 Ma. • The Qilian Shan orogenic belt underwent three stages of tectonic events that began in the early Cenozoic shortly after the India-Eurasia collision. Timing and patterns of the Cenozoic deformation of the Qilian Shan orogenic belt (QSOB) in the northern Tibetan Plateau are key to elucidating the mechanism(s) of plateau growth but remain matters of debate. The Oligocene-Miocene sediments in the Subei Basin, an intermontane basin situated at the junction of the central and southern QSOB, provide direct insight into the Cenozoic deformation of the QSOB. Here, a comprehensive provenance study based on detrital zircon geochronology, paleocurrents, conglomerate components and sedimentary facies in the Subei Basin demonstrates that this region experienced three stages of tectonic events during the Cenozoic. (1) Oligocene strata contain zircons of 200–300, 400–500, 700–1000, 1600–2000 and 2400–2700 Ma, indicating primary derivation from recycled Mesozoic sedimentary rocks in the QSOB and suggesting early Cenozoic deformation in this region. (2) One sample (21.5 Ma) yields similar age populations to those of Oligocene samples, except for the complete disappearance of 200–300 Ma zircons as a result of the widespread deformation of the QSOB. (3) Two samples (18.5–13.6 Ma) show a unimodal age cluster at 400–500 Ma, while one sample (9 Ma) contains zircon ages similar to those of Oligocene samples, indicating tectonic uplift of the southern QSOB in the middle-late Miocene, which is also recorded by the sedimentary transition from fluvial to alluvial fan. Based on these findings and those of previous studies, we suggest that the entire QSOB has undergone multistage tectonic events since the early Cenozoic due to far-field effects associated with the India-Eurasia plate collision and the continued convergence.

Seismic geomorphological analysis of the oligocene-neogene sediments in the north-eastern part of the Black Sea

The evolution of the deep-sea sedimentation system in the north-eastern part of the Black Sea during the Oligocene-Pliocene is considered mainly on the basis of seismic data. The fans and erosion canyons formation time is presumably related to the regressive-transgressive stages in the history of the Eastern Paratethys. The source areas of detrital sediments in the Tuapse Trough are identified. The sedimentation model of the Tuapse Trough and the changes in the Trough’s morphology since the Oligocene were reconstructed based on the analysis of the thickness maps and the onlap surfaces on the northern side of the Shatsky Swell. Paleogeographic maps were compiled for the Late Oligocene-Early Miocene (Maikop), Middle Miocene, and Pliocene.

A new caridean shrimp (Crustacea, Decapoda) from the middle–late Miocene of Sakhalin Island, Russia

A new caridean shrimp (Crustacea, Decapoda) from the middle–late Miocene of Sakhalin Island, Russia

Initial Cenozoic Exhumation of the Northern Chinese Tian Shan Deduced from Apatite (U-Th)/He Thermochronological Data

Abstract The present topography of Tian Shan is related to the India-Asia collision, whereas the mechanisms for the topographic growth of Tian Shan remain at the center of debate partly due to the poorly constrained onset timing of the Cenozoic tectonic deformation. Our new apatite (U-Th)/He (AHe) data in the northern Chinese Tian Shan suggest that rapid cooling commenced at 20.2±4.9 Ma along the northern margin, which is consistent with published fission-track data from the same area and confirms that the youngest component of fission-track has been totally annealed. Moreover, AHe data from the interior mountain suggest that enhanced cooling began at 28.0±2.3 Ma, which is slightly older than that from the northern edge of the mountain. Although thermochronological data suggest that both the interior and northern margin of the northern Chinese Tian Shan have undergone rapid cooling since the late Oligocene-early Miocene, well preservation of relict low-relief surfaces along the northern rim of the northern Chinese Tian Shan and published thermochronological data indicate that the northern Chinese Tian Shan may have experienced differential exhumation in the Cenozoic. Combining the thermochronological and geomorphological evidence, we propose a progressive northward growth model for the northern Chinese Tian Shan. During the late Oligocene and early Miocene, compressive deformation derived from the India-Asia collision have arrived at the northern Tian Shan to reactivate both the interior mountain and its northern margin, while intense exhumation was concentrated in the interior mountain range. Then, deformation extended northward into the foreland basin that may be initiated in the middle-late Miocene.

Northward Growth of the West Kunlun Mountains: Insight From the Age–Elevation Relationship of New Apatite Fission Track Data

The Cenozoic collision between India and Asia promoted the widespread uplift of the Tibetan Plateau, with significant deformation documented in the Pamir Plateau and West Kunlun Mountains. Low-temperature thermochronology and basin provenance analysis have revealed three episodes of rapid deformation and uplift in the Pamir–West Kunlun Mountains during the Cenozoic. However, there is very little low-temperature thermochronology age–elevation relationship (AER) data on fast exhumation events in this area—especially in the West Kunlun Mountains— leading to uncertainty surrounding how these events propagated within and around the mountain range. In this study, we produced an elevation profile across granite located south of Kudi, Xijiang Province, China, to reveal its exhumation history. Apatite fission track AER data show that a rapid exhumation event occurred at ∼26 Ma in the southern West Kunlun Mountains. When combined with published data, we interpret that the initial uplift events related to the India–Asia collision began in the central Pamir, southern West Kunlun, and northern West Kunlun regions during the Late Eocene, Oligocene, and Middle Miocene periods, respectively. Therefore, the Cenozoic northward growth process occurred from south to north around West Kunlun.

Geometry and kinematics of the western part of the NE Qaidam Basin: Implications for the growth of the Tibetan Plateau

Based on field geology, seismic reflection profiling data and isopach maps, the structural deformation pattern, timing of deformation, and mechanism of formation of the western part of the NE Qaidam Basin (including the Pingtai Uplift, Lenghu and Eboliang structural belts) during the Mesozoic and Cenozoic eras have been investigated. Several anticlines in the Lenghu and Eboliang structural belts are generally characterized by double fault systems at different structural levels. At shallower crustal levels, a thrust fault system dominates and at lower levels positive flower structures accommodate oblique shortening, and these are mainly separated by weak strata layers in the Upper Xiaganchaigou Formation, of late Eocene age. Left-step en echelon distributed normal faults and trailing extensional imbricate fan structures consistently demonstrate that the Lenghu and Eboliang structural belts are dominated by dextral transpressional deformation. The western part of the NE Qaidam Basin experienced an initial stage of extension in the Jurassic, which was associated with the formation of several NW-striking normal faults. We hypothesize that most of the deep compressional structures and shallow anticlines were formed due to the SW-directed thrusting of the Qilian Shan since the early Eocene, as a far-field effect of the Indo-Asian “hard” collision. The NNE-directed shortening was associated with dextral transpressional deformation within the western part of the NE Qaidam Basin that took place after the deposition of the Shangyoushashan Formation, of middle-late Miocene age. We interpret this phase of deformation to have been an integral part of the pulsed growth of the whole Tibetan Plateau.

Middle to late Miocene growth of the North Pamir

AbstractHow and when the Pamir formed remains an open question. This study explores Pamir tectonics recorded in a sedimentary section in the eastern Tajik Basin. A prominent lithofacies change that has been recognised regionally is assigned to the middle Miocene (13.5 Ma based on preferred magnetostratigraphic correlation). Closely following this change, detrital zircon U‐Pb age spectra and mudstone bulk‐rock εNd values exhibit a sediment source change from the Central to the North Pamir estimated ca. 12 Ma. At the same time, the stable oxygen and carbon isotopic values of carbonate cements show negative and positive shifts, respectively. Combined with previous studies in both the Tajik and Tarim basins, these results suggest that the North Pamir experienced a middle–late Miocene phase of deformation and surface uplift. This supports models proposing middle–late Miocene Pamir tectonism, and climate models implying that coeval Pamir orogenesis deflected Westerly moisture and affected Asian environments.

Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

Miocene deposits of South America have yielded several species-rich assemblages of caviomorph rodents. They are mostly situated at high and mid- latitudes of the continent, except for the exceptional Honda Group of La Venta, Colombia, the faunal composition of which allowed to describe the late middle Miocene Laventan South American Land Mammal Age (SALMA). In this paper, we describe a new caviomorph assemblage from TAR-31 locality, recently discovered near Tarapoto in Peruvian Amazonia (San Martín Department). Based on mammalian biostratigraphy, this single-phased locality is unambiguously considered to fall within the Laventan SALMA. TAR-31 yielded rodent species found in La Venta, such as the octodontoid Ricardomys longidens Walton, 1990 (nom. nud.), the chinchilloids Microscleromys paradoxalis Walton, 1990 (nom. nud.) and M. cribriphilus Walton, 1990 (nom. nud.), or closely-related taxa. Given these strong taxonomic affinities, we further seize the opportunity to review the rodent dental material from La Venta described in the Ph.D. volume of Walton in 1990 but referred to as nomina nuda. Here we validate the recognition of these former taxa and provide their formal description. TAR-31 documents nine distinct rodent species documenting the four extant superfamilies of Caviomorpha, including a new erethizontoid: Nuyuyomys chinqaska gen. et sp. nov. These fossils document the most diverse caviomorph fauna for the middle Miocene interval of Peruvian Amazonia to date. This rodent discovery from Peru extends the geographical ranges of Ricardomys longidens, Microscleromys paradoxalis, and M. cribriphilus, 1,100 km to the south. Only one postcranial element of rodent was unearthed in TAR-31 (astragalus). This tiny tarsal bone most likely documents one of the two species of Microscleromys and its morphology indicates terrestrial generalist adaptations for this minute chinchilloid.

Elemental and C, O and Mg isotope geochemistry of middle-late Miocene carbonates from the Tuz Gölü Basin (Central Anatolia, Turkey): Evidence for Mediterranean incursions

The Tuz Gölü basin, the largest of the Central Anatolian Neogene basins, is a NW-SE trending fault-controlled depression and includes many subbasins, such as the Ereğli, Ulukışla and Bor subbasins. In the basin, economically important evaporite deposits consisting mostly of halite, gypsum/anhydrite, glauberite and carbonates formed in the middle-late Miocene. The mineralogical and chemical properties and C, O and Mg isotopic compositions of the carbonate minerals that precipitated simultaneously with the other evaporite minerals were investigated using samples from boreholes to determine the precipitation conditions and paleoenvironment of the deposits. The lack of covariance between the δ13C and δ18O values of the samples and the wide range of isotopic compositional variations indicate a basin that was hydrologically open to some degree. In addition, the lack of correlations between δ18O values and MgO/(MgO + CaO), Mg/Ca and Sr/Ca ratios and the wide range of variations in both δ13C and δ18O values indicate that the carbonate minerals precipitated in a lagoonal environment where seawater incursions occurred through transgressions. The δ18O values of the dolomite samples are higher than those of Messinian normal-salinity seawater dolomites and therefore require contributions from evaporative fluids. Additionally, the isotopic data indicate extreme fluctuations in temperature and the inflow-evaporation balance during carbonate precipitation and indicate that the evaporite minerals may have precipitated from the evaporation of seawater trapped within the basin during and after uplift of the region. The Mg isotopic compositions of magnesium-rich carbonates are partially heterogeneous, and the δ26Mg values are higher than the δ25Mg values. Some of the δ26Mg values are close to the δ26Mg values of global seawater (–0.82‰) but higher than the global mean δ26Mg value of river water (–1.09‰). The δ26Mg values are partially within the range of marine sediments (–3.65 to +0.52‰), suggesting seawater contributions to carbonate precipitation.

Increased megathrust shear force drives topographic uplift in the Colombian coastal forearc

The subsidence/uplift patterns of forearc basins are controlled by subduction dynamics and are strongly dependent on the nature of the margin (erosive vs. accretionary). Here, we explore the role that increased megathrust shear force plays in triggering and sustaining the short wavelength topography of coastal forearc regions at erosive margins, where subsidence is supposed to prevail. The northern Colombian coastal forearc contains a ~ 1000 m-high mountain range (Baudó Range) that abruptly stands-up for ~300 km along the northwestern Pacific margin of South America, where the buoyant Nazca plate is subducting at a shallow angle. Field observations and stratigraphic data of Cretaceous to late Neogene volcanic and sedimentary rocks, suggest that the Baudó Range has been uplifting since the middle-late Miocene. The uplift seems to continue nowadays as evidenced by the irregular cliffed and bluffed coastline, steep slopes and high topographic ruggedness in one of the wettest regions on Earth, where weathering and landscape smoothing is expected to be intense. Earthquake focal mechanisms, together with regional-scale N-S-trending sinistral reverse fault structures, west-verging folding, and NW- and NE-oriented topographic lineaments, seems to be related to a trench-perpendicular mostly compressional stress regime. The residual topography along the coastal range of the northern Colombian forearc indicates under-compensation, which may suggest that the relatively thin (~20 km-thick) crust cannot support isostatically the observed topography. We propose that increased shear force along a wide seismogenic zone linked to the shallow subduction of the Nazca plate and a poorly lubricated interface, due to limited sediment dispersal into the trench, drive the ongoing topographic uplift of the region. In contrast, the smoother relief and lower elevations in the southern Pacific coast of Colombia could be explained by a deficit of shear force available to support higher topography.

The link between avian brachial index, flight capability and the neornithine evolutionary radiation.

In dictating the relative distances between the elbow, shoulder and wrist, avian brachial index (BI=humerus/radius-ulna length) likely influences wing kinematics and, therefore, might predict extinct avian flight capability. This underpins the hypothesis that non-neornithine Mesozoic avialans with relatively low BIs (associated with improved flight capabilities) restricted neornithine diversification until after the Cretaceous-Paleogene boundary. Here, correlations between flight metrics (wingbeat frequency (f), stroke angle (θ), wing loading (Q) and aspect ratio) and BI were investigated and vice versa. Additionally, the evolutionary model best describing the phylogenetic distribution of BI, and the temporal patterns in BI, flight metrics, body mass (Mb ), and size-corrected humerus (Lh ) and radius-ulna (Lru ) length were determined. BI was best described by Ornstein-Uhlenbeck processes, with low α values indicating a gradual shift towards a future theoretical optimum. BI also decreased overall through evolutionary time with the flight metrics mirroring temporal patterns of change in BI. Mb , Lh and Lru overall decreased apart from increases in Lh and Lru following the middle-late Miocene (also leading to BI increasing) due to diversifications of the Anatinae and Sphenisciformes. Lh overall decreased further than Lru. Consequently, decreasing Lh mainly contributed to decreasing BI through evolutionary time, implying flight performance increased through neornithine evolution. However, the timings of radiations in these variables implies an Eocene radiation of neornthine flight ecology rather than a rapid expansion into niches vacated by non-neornithine Mesozoic avialians following the Cretaceous-Paleogene boundary. Multiple regressions showed f, θ and Q explained 60% of variation in BI. However, unequivocally evaluating whether BI is related to wing movement (and flight capability) requires direct measures of wing movement for many species, which are currently unavailable. Finally, the findings here and previously observed clade-specificity in BI, suggest flight ecology may also be clade-specific. Hence, the utility of phylogeny in predicting flight ecology requires exploration.

The Structure of the Miocene Northwestern Pacific Ichthyofauna as Revealed By Two Fossil Fish Assemblages From Sakhalin Island, Russia

Two coeval assemblages of fossil fishes came from the middle–late Miocene deposits of Sakhalin Island, Russia. The fish community from the Agnevo Formation consists of 28 species belonging to 15 families of shallow-water fishes, with the predominance of cottoids, stichaeoids, and pleuronectoids. The assemblage from the Kurasi Formation contains fossils of 35 species from 27 fish families and comprises mainly mesopelagic dwellers, such as myctophids, argentiniforms, stomiiforms, and aulopiforms. These assemblages differ mainly in the number of species belonging to extinct genera. Among the 28 fish genera known from the Agnevo Formation, 14 (50%) genera are extinct. In contrast, out of 35 genera described from the Kurasi Formation only three (about 8.6%) genera are extinct. The morphological distances between the fossil and recent congeneric species are more pronounced and defined in the shallow-water community than in the deep-water assemblage. The differences in taxonomic composition between the fossil assemblages likely reflect the different influence of the climatic and geographic events in the Neogene and Quarternary on the evolutionary rates of shallow- and deep-water fish communities.

New late Oligocene rodent faunas from the Pannonian basin

The rodent associations from the late Oligocene deposits of Ugljevik and Paragovo in the Pannonian basin are described. Pannoniamys paragovensis, a new genus and species of Spalacidae, is defined. The published data from a third late Oligocene locality in the area (Banovići) is included in the discussion of the changes in community structure through the time-interval studied. Although the composition of the rodent faunas studied differs, the dominating cricetid genus in all three associations is Deperetomys, a genus that appears in western Europe during the late middle Miocene. While the late Oligocene rodent record of central and southwestern Europe is characterised by endemic development, the regime in the Balkans seems to have been one of multiple immigrations and replacements. The late Oligocene age of the rodent fauna from Ugljevik estimated at about 26 Ma, provides a minimum age for the start of rifting in the Pannonian basin, some 6 Ma earlier than previously documented.

The new small emballonurid (Emballonuridae, Chiroptera, Mammalia) from the Miocene of Africa: its phylogenetic and palaeogeographic implications

ABSTRACT The fossil Afrillonura namibensis gen. et sp. nov. from the late Middle Miocene (12–13 Ma) site of Berg Aukas I, Namibia was a medium-sized emballonurid with a gracile dentition. It shows a mosaic combination of dental features of extant Emballonurini and distinct plesiomorphies suggesting its basal phylogenetic position close to the root of the extant clades of the tribe. It shares many odontological characteristics with Coleura and Paremballonura but also with some species of Emballonura. Afrillonura namibensis gen. et sp. nov. differs from most members of the tribe Emballonurini particularly in the presence of a vestigial paracrista on M1, resembling the state in the Palaeogene genus Dhofarella. Together with other available fossils, the new material from Namibia supports the hypothesis of the African origin of the family Emballonuridae. Further phylogenetic conclusions and biogeographic scenarios of emballonurid ancestral distribution are discussed.

Not that young: combining plastid phylogenomic, plate tectonic and fossil evidence indicates a Palaeogene diversification of Cycadaceae

Background and AimsPrevious molecular dating studies revealed historical mass extinctions and recent radiations of extant cycads, but debates still exist between palaeobotanists and evolutionary biologists regarding the origin and evolution of Cycadaceae.MethodsUsing whole plastomic data, we revisited the phylogeny of this family and found the Palawan endemic Cycas clade was strongly related to all lineages from Southeast Eurasia, coinciding with a plate drift event occurring in the Early Oligocene. By integrating fossil and biogeographical calibrations as well as molecular data from protein-coding genes, we established different calibration schemes and tested competing evolutionary timelines of Cycadaceae.Key ResultsWe found recent dispersal cannot explain the distribution of Palawan Cycas, yet the scenario including the tectonic calibration yielded a mean crown age of extant Cycadaceae of ~69–43 million years ago by different tree priors, consistent with multiple Palaeogene fossils assigned to this family. Biogeographical analyses incorporating fossil distributions revealed East Asia as the ancestral area of Cycadaceae.ConclusionsOur findings challenge the previously proposed Middle–Late Miocene diversification of cycads and an Indochina origin for Cycadaceae and highlight the importance of combining phylogenetic clades, tectonic events and fossils for rebuilding the evolutionary history of lineages that have undergone massive extinctions.

Aragonictis araid, gen. et sp. nov., a small-sized hypercarnivore (Carnivora, Mustelidae) from the upper middle Miocene of the Iberian Peninsula (Spain)

ABSTRACT Small to medium-sized mustelids from the last 18 million years represent a heterogeneous group of carnivorans with a wide-ranging record in the northern hemisphere. They were first referred to the genera Mustela and Martes, but lately ascribed to the latter, and hence considered as the longest-lived genus within Mustelidae. However, a great many of these forms have been based upon fragmentary material and Martes has conformed progressively to a wastebasket nomen for species of uncertain relationships. Here, we describe dentognathic material of a small-sized mustelid from three middle Miocene (MN7 + 8, latest Aragonian) localities of the Iberian Peninsula that constitutes a new genus and species. Aragonictis araid, gen. et sp. nov. represents a distinct taxon if compared with early/middle Miocene forms ascribed to “Martes” spp., especially the similar-sized early Miocene Circamustela? laevidens and the middle Miocene “Martes” caedoti and “Martes” delphinensis. The finding of particular features in A. araid (low p2–3, loss or reduction of the p4 accessory cuspid with its main cuspid centrally located, presence of a sharp, beveled and lingually open m1 talonid, and reduction of M1 lingual platform) indicates affinities with the late Miocene Circamustela in the range of hypercarnivory. Our reassessment of “Martes” indicates possible evidence of cladogenesis for Miocene mustelidae with, at least, two different events being recognized in Europe—the latter during MN7 + 8 to MN9 with presence of Aragonictis and Circamustela. The finding of A. araid further confirms the presence of more densely forested environments than expected in inner Iberia during the latest middle Miocene.