Continental Vertebrate Research Articles

Fishes and squamate reptiles from the Pliocene sites of Berești and Mălușteni (eastern Romania) – A reassessment of old but poorly known material

This paper performs a revision of teleost fish and squamate reptile material from the Early Pliocene sites of Berești and Mălușteni (eastern Romania), found in old collections, but never described in detail. The fish assemblage includes a few cyprinid species (Rutilus robustus, Rutilus cf. R. frisii, Scardinius ponticus, Barbus sp., Tinca sp.), Silurus cf. S. soldatovi, pikes (Esox moldavicus and Esox sp.), as well as indeterminate remains of salmonid, percid and sparid fishes. Squamate reptiles are represented by isolated vertebral and cranial material assigned to the anguid lizard Pseudopus pannonicus, as well as by isolated snake vertebrae belonging to the viperid Macrovipera sp. This is the most taxonomically diverse Pliocene ectothermic vertebrate assemblage described so far from the Romanian Carpathian Foreland. The obtained results contribute to a better understanding of continental vertebrate fauna evolution in the eastern part of central Europe.

Sedimentological evolution of the Quibas site: High-resolution glacial/interglacial dynamics in a terrestrial pre-Jaramillo to post-Jaramillo sequence from southern Iberian Peninsula

The sedimentary infill of the Quibas karstic site (Early Pleistocene, southern Spain) represents the only continuous succession with remains of continental vertebrates in Europe from pre-Jaramillo to post-Jaramillo age. The Quibas site, with a significant paleontological record, is dated between 1.1 and 0.9 Ma and offers a unique opportunity to carry out a paleoclimatic reconstruction of the time period immediately after the arrival of the first humans to western Europe. For this reason, defining the dominant sedimentary processes in the different stratigraphic units and the associated paleoenvironment is essential. The Quibas site is made up of two karstic features with two stratigraphic sequences: Quibas-Cueva, containing six lithostratigraphic units, and Quibas-Sima, which contains seven lithostratigraphic units. The detailed description and analyses of the stratigraphic sections have allowed the characterization of various autochthonous and allochthonous facies of cave deposits. Paleoclimatic proxies, inferred from sedimentological analyses, reveal a record of several alternating humid and arid phases resulting from the Early Pleistocene glacial-interglacial cycles, allowing correlation to the marine oxygen isotope record. The lowermost units (pre-Jaramillo) were deposited during a long-lasting interglacial, correlated to MIS 33–31. It was followed by an increase in aridity in the intermediate units of Quibas-Sima and uppermost unit of Quibas-Cueva (Jaramillo), revealing the beginning of a glacial period at the start of the Jaramillo subchron (1 Ma), which can be correlated to MIS 30. The upper Jaramillo and post-Jaramillo units suggest these were deposited in alternating periods of aridity and humid conditions, although less humid than the pre-Jaramillo period, probably representing the MIS 29 interglacial, the MIS 28 glacial and the MIS 27 interglacial.

PALYNOSTRATIGRAPHIC AND PALAEOENVIRONMENTAL INVESTIGATIONS OF THE MAASTRICHTIAN FROM OARDA DE JOS (SOUTHWESTERN TRANSYLVANIAN BASIN)

A palynological, palynofacies and organic geochemical investigation of the Upper Cretaceous continental vertebrate site of Oarda de Jos allowed us to constrain its age and to make more detailed inferences about its depositional environment. The recovered palynomorph assemblage is represented mainly by angiosperm pollen and fern spores, alongside rare taxa of gymnosperms. Biostratigraphically significant taxa identified in the assemblage restrict the age of the studies deposits to the later early Maastrichtian. The palynofloral evidence indicates plant communities that mainly preferred higher-altitude areas and cooler-wetter conditions. However, a spore and pollen assemblage which derives from vegetation typical of lacustrine areas or riverbanks also occurs in the studied deposits. The studied palynoflora shows quite significant differences compared to previously published palynological assemblages from the same geological unit (the Sebeș Formation), although from deposits located slightly to the north, at Pâclișa. Organic geochemical data show that certain organic biomarkers such as n-alkanes n-C16 to n-C18 reach the highest values, and indicate that they may derive from freshwater colonial green algae such as Scenedesmus. The palynofacies constituents used to reconstruct the depositional environment suggest an exclusive terrestrial organic matter deposited in a stagnant-water fluvial/lacustrine environment.

Updated cranial and mandibular description of the Late Cretaceous (Maastrichtian) baenid turtle Saxochelys gilberti based on micro-computed tomography scans and new information on the holotype-shell association

Saxochelys gilberti is a baenid turtle from the Late Cretaceous Hell Creek Formation of the United States of America known from cranial, shell, and other postcranial material. Baenid turtles are taxonomically diverse and common fossil elements within Late Cretaceous through Eocene faunas. Detailed anatomical knowledge is critical to understanding the systematics and morphological evolution of the group. This is particularly important as baenids represent an important group of continental vertebrates that survived the mass extinction event associated with the Cretaceous/Paleogene boundary. High-resolution micro-computed tomography scanning of the holotype skull reveals additional anatomical details for the already well-known Saxochelys gilberti. This includes the revision of some anatomical statements from the original description, but also detailed knowledge on internal anatomical features of the braincase and the description of a well-preserved axis (cervical vertebra 2). Our new detailed description and previous work on the shell and postcrania make Saxochelys one of the best-described, nearly complete baenid turtles, which are often only known from either isolated shell or cranial material. A revised phylogenetic analysis confirms the position of Saxochelys gilberti as a derived baenid (Eubaeninae) more closely related to Baena arenosa than to Eubaena cephalica.

Integrated biostratigraphy of Upper Cretaceous deposits from an exceptional continental vertebrate-bearing marine section (Transylvanian Basin, Romania) provides new constraints on the advent of ‘dwarf dinosaur’ faunas in Eastern Europe

The present paper outlines the results of a detailed study of calcareous nannofossils and small foraminifera made on Campanian marine deposits from the southwestern part of the Transylvanian Basin, Romania, part of the marine-to-continental transitional Petrești succession that yielded the oldest temporally well-constrained continental vertebrate remains in this area. These results are integrated with new and previously published palynostratigraphic information as well as with novel detrital zircon geochronometry data. All three groups of fossils (calcareous nannofossils, small foraminifera, and palynomorphs) convergently indicate an early to middle Late Campanian age for the marine part of the Petrești section. Based on detrital zircon analyses, the most likely maximum depositional age of the studied deposits is 76 ± 1.7 Ma, thus confirming the age supported by microfossil assemblages. Palaeoenvironmental interpretation of the fossil assemblages recovered from the marine part of the Petrești section suggests that despite their flysch-like facies, these beds were deposited in a continental shelf setting, under suboxic conditions and frequent fluctuations in nutrient supply to the seafloor, but quite stable environmental conditions within the water column. The synthesis of all currently available biostratigraphic and geochronologic data from the Petrești succession suggests a middle-late Late Campanian start for the expansion of the emergent land areas that made up the latest Cretaceous Hațeg Island, earlier than previously accepted dates (Maastrichtian) for this event. Furthermore, it documents the establishment of a diversified continental vertebrate faunal assemblage by the second half of the Late Campanian on these emergent lands while also providing further evidence for a later, post-Campanian arrival of certain iconic Hațeg Island dinosaur groups such as titanosaurs and hadrosauroids. Finally, our data show that kogaionid multituberculate mammals were already members of the earliest known Hațeg Island faunas, extending the fossil record of this group from the Maastrichtian into the later part of the middle Late Campanian.

First dinosaur tracks found in the Mulichinco Formation (Lower Cretaceous), Neuquén Basin, Argentina: Paleoenvironmental implications

This study focuses on the analysis of the first dinosaur tracks discovered in the Mulichinco Formation, Neuquén Basin, Argentina. The deposition of this unit occurred during the early Valanginian, Early Cretaceous, making it the oldest known record of dinosaur tracks for that period in the basin. The aim of this study is to provide a paleoenvironmental interpretation of the area and potential trackmakers based on the morphology of the tracks and the facies analysis of the depositional system. The depositional system evolved from a moderately sinuous fluvial system in the lower interval to a braid distal plain system with the development of bodies of water without marine influence, culminating in an estuary with marine influence in the upper interval. The paleoenvironmental conditions during the deposition of the unit were favourable for the presence and interaction of diversity large continental vertebrates. The track-bearing surfaces in the lower interval suggest that the organisms exploited the temporary gaps created between channel migration and floodplain formation as areas for transit or water sources. In the middle interval, the abundant presence of traces fossils of invertebrates and symmetrical ripples suggest a more stable depositional system where fluctuations in the water column were common. The co-occurrence of various track-makers and remains of large vertebrates described in the Mulichinco Formation is unusual among track sites at the basin. Overall, this study provides new insights into the Early Cretaceous paleoenvironmental conditions of the Neuquén Basin and the diversity of large vertebrates that inhabited the region during this time.

Late Triassic–Early Jurassic continental vertebrates and their environmental context from the Junggar Basin, Xinjiang, NW China

Abstract Vertebrate assemblages from the Junggar Basin in Xinjiang, China, are the only ones known from palaeo-Arctic continental strata of Late Triassic and Early Jurassic age. Here we present a preliminary description of these new assemblages, focusing on the underappreciated Arctic palaeolatitude and winter freezing of this coal-bearing sequence. Mostly collected during NIGPAS-led stratigraphic studies in the 2016–17 field seasons, new assemblages include: (1) small to large sculptured palaeonisciform cranial elements and scales, small associated palaeonisciforms, a sauropterygian tooth, large-dinosaur bioturbation and additional unidentified small vertebrate bones from the Haojiagou Formation (?upper Norian–Rhaetian); (2) a medium-sized brontozoid dinosaur footprint and a previously described possible Anomoepus track from the Badaowan Formation (Hettangian–?Pliensbachian); and (3) a hybodont shark egg case of the form taxon Palaeoxyris (only the third reported from Early Jurassic age strata of China), numerous associated and fragmentary small palaeonisciform remains (including one partial skull and several small skeletons), and another possible Anomoepus track and associated dinoturbation from the Sangonghe Formation (?Pliensbachian–Toarcian). A possible ash associated with the aforementioned lower Sangonghe fish skull has produced a laser ablation inductively coupled plasma mass spectrometry age of roughly 186 Ma, consistent with a Pliensbachian age. We are optimistic that there will be many additional discoveries from early Mesozoic age strata of the Junggar Basin, the importance of which for understanding Earth system processes cannot be overemphasized.

Accelerated body size evolution in upland environments is correlated with recent speciation in South American freshwater fishes

Speciation rates vary greatly among taxa and regions and are shaped by both biotic and abiotic factors. However, the relative importance and interactions of these factors are not well understood. Here we investigate the potential drivers of speciation rates in South American freshwater fishes, the most diverse continental vertebrate fauna, by examining the roles of multiple biotic and abiotic factors. We integrate a dataset on species geographic distribution, phylogenetic, morphological, climatic, and habitat data. We find that Late Neogene-Quaternary speciation events are strongly associated with body-size evolution, particularly in lineages with small body sizes that inhabit higher elevations near the continental periphery. Conversely, the effects of temperature, area, and diversity-dependence, often thought to facilitate speciation, are negligible. By evaluating multiple factors simultaneously, we demonstrate that habitat characteristics associated with elevation, as well as body size evolution, correlate with rapid speciation in South American freshwater fishes. Our study emphasizes the importance of integrative approaches that consider the interplay of biotic and abiotic factors in generating macroecological patterns of species diversity.

The dawn of the Late Villafranchian: Paleoenvironment and age of the Pantalla paleontological site (Italy; Early Pleistocene)

Biochronology is the most widely used method for organizing the successions of continental vertebrate faunas in geological time and for allowing the correlation of continental deposits. However, due to the fragmentary nature of the paleontological record and the diachronicity of first and last occurrences of vertebrate taxa in different areas (i.e., bioevents), it is difficult to precisely define the temporal boundaries between biochronological units. That is why it is crucial to calibrate biochronological data with independent proxies wherever possible. Here, thanks to an interdisciplinary approach that combines sedimentology and stratigraphy, vertebrate paleontology, micropaleontology (ostracods), palynology, and geochronology, we provide a chronological framework and a paleoenvironmental reconstruction of the paleontological site of Pantalla (Central Italy). The combination between biochronological/biostratigraphic and geochronological (U-series/ESR dating and paleomagnetism) data allows us to refer the site to c. 2.2 Ma, i.e., in the transition phase between the Middle and Late Villafranchian in the European biochronological scheme. We reconstruct the environment as a fluvial area with a frequently flooded wet floodplain and marked (probably seasonal) variations of the water level of the channel river. The depositional system was surrounded by a conifer-dominated forest, which is suggestive of a glacial phase.

Contour marks as potential indicators of evaporation rates in the early Permian continental vertebrate site Bromacker (Thuringia, Central Germany)

Reconstructing the climate of the past requires archives that bear proxy information on temperature, precipitation, or atmospheric composition, for example. In this study we use contour marks as potential water level marks in mud sediments to reconstruct local evaporation rates at the Bromacker lagerstaette site in the Early Permian. The measured values indicate a daily evaporation of 1.5–3.75 mm with a median value of 2.25 mm/day. The calculated evaporation rates are compared with modern ones to estimating moisture, precipitation and seasonal climate. For evaluating reconstructed precipitation and evapotranspiration rates, values simulated by global climate models and calculated from geochemical datasets are furthermore incorporated. For the first time, quantitative data and models elucidate the climate of the Tambach Formation and Bromacker lagerstaette against the background of the pivotal transition from the Carboniferous Ice House to the Permian Hothouse climate. Our results suggest a strongly seasonal climate with wet summers and dry winters in a mountainous region based on unexpectedly low temperatures (10.9–15.0 °C) considering the palaeo-location of the site in the tropical belt during the Early Permian. According to the modern vegetation model by Holdridge a moist forest biome is suggested for the Bromacker lagerstaette.

The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones

Early Cretaceous (late Barremian – early Aptian) fissure fill deposits near Balve, North Rhine Westphalia, Germany, have yielded a rich continental vertebrate fauna over the course of the last two decades. More than 250 fragmentary specimens, including more than 150 osteoderms (i.e., granicones), represent the late Early Cretaceous helochelydrid Helochelydra nopcsai, which had previously been reported from the UK, France, and Spain. The new material mostly differs from that from the type section by exhibiting a reduced to absent entoplastral scute and by displaying distinct cranial scute sulci, both of which are interpreted as intraspecific variation. Although morphological insights are limited, the new material reveals that the visceral cavity extends anteriorly and posteriorly to the bridge, a relatively novel feature previously reported for an eclectic mix of compsemydids, pleurosternids, and other helochelydrids. The available sample of granicones reveals great shape diversity, but a morphometric analysis concludes that no distinct morphotypes exist.

El Barrancazo: a new locality of possible semi-aquatic turtle tracks from the Upper Triassic of Cortes de Pallás (Eastern Iberia)

This work describes the new vertebrate tracksite named El Barrancazo, located in Cortes de Pallás (Eastern Iberia). This new site turns this area into the one that concentrates the largest number of vertebrate footprints from the Upper Triassic of Iberia. The footprints are presented as natural casts distributed in isolated blocks belonging to the Manuel Formation (K2, Keuper facies), deposited during the Carnian Pluvial Episode (Late Triassic). The blocks come from two beds of the same outcrop. The tracks are made up of sub-parallel digital impressions, displaying occasional curved traces, often without forming a complete outline, and showing a set of features such as lateral and posterior overhangs, longitudinal striations or digital reflectures, among others. These features, taken together with the sedimentological analysis carried out, suggest that animals moving in totally or partially buoyant conditions in a fluvial environment produced most of these tracks. The size and morphology of these paleoichnological impressions suggest that they were probably produced, in some cases, by turtles, adding to the understanding of the paleoenvironmental and paleofaunistic conditions of the Late Triassic of Iberia during the Carnian, a key period in the evolution of different groups of continental vertebrates. In this paper we show the comparative study of the three sites described to date in Cortes de Pallás and an analysis of the interplay of trackmaker organism, animal behavior and substrate in the resulting morphology of tracks made under subaqueous conditions.

Maastrichtian palynological assemblages from the Chorrillo Formation, Patagonia, Argentina

The Chorrillo Formation is an uppermost Cretaceous continental sequence cropping out in the southernmost region of Patagonia. Recent field trips carried out in the region allowed the recognition of a highly diverse record of continental vertebrates, invertebrates, and plants that inhabited the region during the latest Cretaceous. In this study, a palynological analysis derived from an exhaustive sampling in the unit is presented. The recovered taxa include 44 spore species, 28 gymnosperm and 55 angiosperm pollen taxa, as well as 7 algae, and fungal remains. Two new taxa of unknown affinities (Acylomurus silviae sp. nov. and Lusatisporis choiols sp. nov.) and a new alga (Sphaeroplea striatocristata sp. nov.,) are proposed. Taxonomic composition of the palynological assemblages suggest humid and temperate to warm climatic conditions. Based on the stratigraphic range of the identified taxa, a Maastrichtian age is suggested, coincident with previous interpretations derived from the stratigraphic relationships of the Chorrillo Formation. Comparisons with other latest Cretaceous to Danian assemblages from southern Gondwana, carried out using multivariate statistical methods, indicate that the assemblage from the Chorrillo Formation has greatest similarities with the palynological assemblages of the Maastrichtian La Irene and La Anita formations, the upper levels of the Monte Chico Formation, and with the Maastrichtian levels of the Lefipán Formation, all units cropping out in central and southern Patagonia.

An Eudromaeosaurian Theropod from Lo Hueco (Upper Cretaceous. Central Spain)

The Lo Hueco fossil site (Cuenca, Spain) is one of the most relevant localities for the study of Late Cretaceous continental vertebrate faunas from Europe. The fossil record of theropod dinosaurs from this locality is represented by scarce isolated postcranial materials that were preliminarily attributed to abelisaurids and to a possible giant bird, in addition to a large assemblage of isolated teeth that were related to different maniraptoran clades. Here, we describe an isolated partial left tibia articulated with the proximal tarsals and discuss their taxonomic affinities. A review of the European fossil record of Late Cretaceous theropods was performed to analyze possible changes in the faunistical composition during this period. The specimen from Lo Hueco exhibits some characters that have been interpreted as apomorphies for maniraptoran coelurosaurs and a combination of features compatible with deinonychosaurians. Within this clade, the specimen is more favorably comparable with velociraptorine dromaeosaurids and is tentatively interpreted as a member of this group. This specimen is one of the few non-dental specimens of dromaeosaurids described thus far from the Upper Cretaceous of the Iberian Peninsula and contributes to a better understanding of the composition and evolutionary history of the European theropod fauna during the last stages of the Mesozoic.

Landscape dynamics and diversification of the megadiverse South American freshwater fish fauna

Landscape dynamics are widely thought to govern the tempo and mode of continental radiations, yet the effects of river network rearrangements on dispersal and lineage diversification remain poorly understood. We integrated an unprecedented occurrence dataset of 4,967 species with a newly compiled, time-calibrated phylogeny of South American freshwater fishes-the most species-rich continental vertebrate fauna on Earth-to track the evolutionary processes associated with hydrogeographic events over 100 Ma. Net lineage diversification was heterogeneous through time, across space, and among clades. Five abrupt shifts in net diversification rates occurred during the Paleogene and Miocene (between 30 and 7 Ma) in association with major landscape evolution events. Net diversification accelerated from the Miocene to the Recent (c. 20 to 0 Ma), with Western Amazonia having the highest rates of insitu diversification, which led to it being an important source of species dispersing to other regions. All regional biotic interchanges were associated with documented hydrogeographic events and the formation of biogeographic corridors, including the Early Miocene (c. 23 to 16 Ma) uplift of the Serra do Mar and Serra da Mantiqueira and the Late Miocene (c. 10 Ma) uplift of the Northern Andes and associated formation of the modern transcontinental Amazon River. The combination of high diversification rates and extensive biotic interchange associated with Western Amazonia yielded its extraordinary contemporary richness and phylogenetic endemism. Our results support the hypothesis that landscape dynamics, which shaped the history of drainage basin connections, strongly affected the assembly and diversification of basin-wide fish faunas.

New records of continental vertebrates from the Triassic of the Atacama Desert, northern Chile

This contribution describes new vertebrate remains found in Triassic strata informally known as “Estratos El Bordo”, in the Atacama Desert, northern Chile. These include the first temnospondyl record in the El Bordo Basin, plus actinopterygians referable to the clade Pseudobeaconiidae and a second form with affinities to the incertae sedis ray-finned fish Guaymayenia paramillensis. Associated to these taxa, we describe two spiral coprolites. Their vertebrate producers are discussed. These new freshwater vertebrates add to previous archosaur records from “Estratos El Bordo”, represented by the putative aetosaur Chilenosuchus forttae, an indeterminate silesaurid and a fragmentary indeterminate Crocodylomorpha. Vertebrate remains here described show affinities to the known diversity from the Cuyana Basin of Argentina, but differ from those recorded in northern Argentina (Ischigualasto-Villa Unión Basin) and southern Brazil (Paraná Basin). This suggests preliminary paleoenvironmental insights for the continental vertebrates that inhabited the southwestern margin of South America during the Triassic. The new findings also support a Middle-to-Upper Triassic age for the “Estratos El Bordo” unit, as previously indicated by radioisotopic datating.

The “mid”-Cretaceous (Lower Cenomanian) Continental Vertebrates of Gara Samani, Algeria. Sedimentological Framework and Palaeodiversity

Excellent outcrops of the upper part of the “Continental Intercalaire” deposits occur in the Gara Samani area, southern Algeria. These strata are recognised herein as belonging to the Gara Samani Formation, which is composed of the Samani Vertebrate-rich Sand Member, the Samani Sandstone Member and the Méguidène Stratified Sand Member. The first two members are from a fluvial system and the last member corresponds to an aeolian (dune and interdune) system. They have preserved one of the most diverse continental vertebrate faunas of latest Albian–early Cenomanian age yet known from northern Africa. Most of the taxa identified there, cited for the first time for the “mid”-Cretaceous of Algeria, have not been analysed in detail so far; and many of them have never been figured. The faunal list of vertebrates from this locality was supplemented thanks to detailed analysis of new and relatively abundant finds. As a consequence, the Gara Samani vertebrate assemblage is recognised as composed of elasmobranchs (two Hybodontiformes, i.e., Tribodus sp. and Distobatidae indet.; and a Batoidea, Onchopristis numida), actinopterygians (Bawitius sp., Adrianaichthys sp., Obaichthys africanus, and Calamopleurus africanus), sarcopterygians (Mawsoniidae indet. and the Dipnoi, cf. Lavocatodus humei and Neoceratodus africanus), testudines (at least two Pelomedusoides, one of them being a representative of Araripemydidae), crocodyliforms (all remains being compatible with Neosuchia, represented at least by Elosuchus broinae), ornithocheirid pterosaurs, and non-avian dinosaurs (titanosauriform sauropods and at least two theropods, Spinosaurus aegyptiacus and Carcharodontosaurus saharicus). This fauna association displays close similarities to contemporaneous ones from North Africa, especially with that from the Kem Kem beds.

Quibas-Sima: A unique 1 ma-old vertebrate succession in southern Iberian Peninsula

With the identification of the Jaramillo geomagnetic subchron, the late Early Pleistocene vertebrate succession of the Quibas-Sima section (Quibas karstic complex, southern Spain) represents a time span scarcely recorded in Europe. To complete the existing chronostratigraphic framework published earlier by Piñero et al. (2020), we provide here additional new information about the lithostratigraphy and micromammal succession along the sedimentary sequence. Seven lithostratigraphic units have been differentiated (QS-1 to QS-7) at Quibas-Sima, documenting an almost continuous small mammal record, including representatives of the families Soricidae, Erinaceidae, Rhinolophidae, Vespertilionidae, Arvicolidae, Muridae, Gliridae, Sciuridae, Leporidae and Ochotonidae. The small mammal association indicates that units QS-1 to QS-4 have an intermediate biostratigraphic position between the sites of Fuente Nueva 3 (ca. 1.2 Ma) and Cueva Victoria (ca. 0.9 Ma). New numerical age result from the combined U-series/ESR dating of one equid tooth from QS-3 consistently support the general chronostratigraphic framework based on magnetostratigraphy and biostratigraphic inferences by confirming a post-Olduvai age. Based on an estimation of the sedimentation rate during the Jaramillo subchron, these broad chronological constraints may be confidently refined to approx. 1.1–0.9 Ma for the whole sequence. While we acknowledge the existing uncertainty associated to this age range, it is nevertheless consistent with biostratigraphic evidence indicating that all stratigraphic units most likely do not significantly differ from a chronological point of view. Both independent proxies (biostratigraphy and the sedimentation rate) strongly suggest that the sedimentary sequence covers a relatively short time interval (<200 kyr). These results place the Quibas-Sima sequence as one of the longest and most complete pre-Jaramillo (QS-1) to Jaramillo (QS-2 to QS-5) continental vertebrate succession in Europe.

Late Campanian-Early Maastrichtian Vertebrates From The James Ross Basin, West Antarctica: Updated Synthesis, Biostratigraphy, And Paleobiogeography.

The Snow Hill Island Formation (SHIF; late Campanian - early Maastrichtian) crops out in the northeast of the Antarctic Peninsula and constitutes the basal part of the late Campanian-early Maastrichtian sedimentary succession of the James Ross Basin (NG Sequence). Its major exposures occur at the James Ross and Vega islands. Several fossil-bearing localities have been identified in the SHIF providing a valuable fauna of invertebrates and vertebrates, and flora. Our study focuses on the vertebrate fauna recovered at Gamma and Cape Lamb members of the SHIF. The marine vertebrate assemblages include chondrichthyans, actinopterygians, and marine reptiles (elasmosaurid plesiosaurs and mosasaurs). A diverse terrestrial vertebrate assemblage has been reported being characterized by dinosaurs (sauropod, elasmarian ornithopods, nodosaurid ankylosaur, and a paravian theropod), pterosaurs and birds. Most SHIF dinosaurs share close affinities with penecontemporaneous taxa from southern South America, indicating that at least some continental vertebrates could disperse between southern South America and Antarctica during the Late Cretaceous. The Snow Hill Island Formation provides the most diverse Late Cretaceous marine and continental faunas from Antarctica. The present study summarizes previous and new vertebrate findings with the best actualized stratigraphical framework, providing a more complete fauna association and analyzing further perspectives.

The age of North America’s youngest Paleozoic continental vertebrates: a review of data from the Middle Permian Pease River (Texas) and El Reno (Oklahoma) Groups

The youngest Paleozoic vertebrate-bearing continental deposits of North America are Middle Permian (Guadalupian) in age and occur in the Chickasha Formation (El Reno Group) of central Oklahoma and the lithostratigraphically lower San Angelo Formation (Pease River Group) of North-Central Texas. Although regarded originally as Guadalupian, these deposits have been assigned recently to the Early Permian on the basis of marine fossils and questionable lithostratigraphic correlations between marine and continental strata. A review of ammonoid genera recovered from the Blaine Formation, which overlies both the Chickasha and San Angelo in Oklahoma and Texas, shows that they range globally in age from the Early to Late Permian, but most occur in the Guadalupian or Middle Permian. A modest but intensively studied paleobotanical record of compression fossils from the San Angelo, as well as palynomorphs in rocks associated with the Chickasha, presents an unquestionably Middle to Late Permian flora dominated by voltzian conifers. The Chickasha and San Angelo vertebrate assemblages are overwhelmingly dominated by large caseid synapsids and indicate a biostratigraphic signal of early Guadalupian. The occurrence of the tupilakosaurid temnospondylSlaugenhopia, the parareptileMacroleter, and the eureptileRothianiscussuggests a Roadian age (lowermost Guadalupian) given the global records of closely related forms. These plant and vertebrate assemblages contrast sharply with those of underlying Cisuralian rocks of the Hennessey Formation of Oklahoma and the Clear Fork Formation of Texas, both of which are much more fossiliferous than those of the Guadalupian in the region. A barren interval of up to 300 m in thickness separates these fossil-bearing intervals. This true void in the late Kungurian was first reported a half century ago but has not been recognized in recent biochronology studies. Our findings, as well as those of other vertebrate paleontologists who have evaluated the San Angelo and Chickasha data by other means, strongly refute the current notion of “Olson’s Gap” as spanning most of the Roadian.