Vertebrate Assemblages Research Articles

Early Pleistocene (Epivillafranchian) vertebrates from Portugal: An updated review

The Epivillafranchian (1.2 to 0.8 Ma) fossil vertebrate assemblages of Portugal are extremely poorly known compared with to those from the eastern half of Iberia. We review material from one of the two localities of this age previously known in Portugal, Algoz, and present a new microvertebrate locality, Santa Margarida. Both localities are situated in Algarve (South Portugal). The fauna of Algoz includes Hippopotamus antiquus, Eucladoceros sp., Metacervocerus rhenanus and an indeterminate leporid. There are remains of at least two individuals of each deer species from Algoz, although most of the remains are from the same juvenile individual of Eucladoceros sp., about 6 months old. The age of Algoz is determined to be ∼1.2 Ma given the combination of species and their biometrical and morphological characters. Santa Margarida has at least ten species of microvertebrates: Lacertidae indet., Crocidura sp., Sorex sp., Oryctolagus cf. cuniculus, Eliomys cf. quercinus, Apodemus cf. sylvaticus, Allocricetus bursae, Victoriamys chalinei, Iberomys huescarensis, and Iberomys brecciensis. This is the first occurrence of Victoriamys chalinei and Iberomys huescarensis –two vole species typical from the Early Pleistocene – in Portugal. Santa Margarida is younger than Algoz, ranging between ∼0.9 and ∼0.6 Ma, which means that the Early-Middle Pleistocene transition could be represented by this locality.

The Cretaceous post-rift series from the Portuguese onshore ranges of the West Iberian Margin and their history of research

The thick post-rift series that covers the Triassic to Lower Cretaceous sedimentary succession of the Lusitanian Basin, in west central Portugal, is crucial to understanding the Mesozoic evolution of the West Iberian Margin, motivating a long history of studies, including those by Daniel Sharpe (1806–56). They record platform carbonates interbedded with marginal marine and alluvial facies. The post-rift infill was deposited above a late Aptian breakup unconformity and is organized into three unconformity bounded sequences: ‘UBS-4A’ (upper Aptian–upper Cenomanian), ‘UBS-4B’ (lower Turonian–lower Campanian) and ‘UBS-5B’ (lower Campanian–Maastrichtian). The first comprises alluvial siliciclastics and shallow-marine, carbonate sequences rich in Tethyan faunas with ammonites and rudists. During the late Cenomanian, the carbonate platform entirely covered the onshore sectors of the Lusitanian Basin. Several diapiric axes controlled the differentiation of inner platform areas with corals and rudists. The infill of ‘UBS-4B’ occurred after the tectonic uplift and emersion of the sectors located to the south of first-order Nazaré Fault Zone. The platform carbonate facies were overlain by regressive micaceous and alluvial coarse siliciclastics. The sequence ‘UBS-5’ overlies a lower Campanian unconformity and has a Campanian–Maastrichtian thick record of alluvial to lagoonal, reddish pelites, rich in vertebrate assemblages.

Review of two marine vertebrate assemblages from the Arauco Basin (central Chile) reveals diversity changes throughout the Maastrichtian

Upper Cretaceous vertebrate records from Chile are mostly known by historical mentions with unknown repositories and uncertain stratigraphic provenance. This contribution reviews and complements two marine vertebrate assemblages from the Upper Cretaceous of central Chile, which were part of the ancient Arauco Basin. The oldest assemblage (lower Maastrichtian) comprises abundant condrichthyans referred to Carcharias gracilis, Odontaspis cf. winkleri, Scapanorhynchus sp., Centrophoroides appendiculatus, Squatina sp., Cretorectolobus sp., Orectolobidae indet., Paraorthacodus sp., Ischyrhiza chilensis and Biropristis landbecki, which adds to the previously reported occurrences of Echinorhinus sp. and Myledaphus araucanus. In addition, chimeroids referred to as Edaphodon kawai and remains of a leatherback turtle referable to Mesodermochelys sp. are here described, the latter being its first occurrence outside Japan. The younger assemblage (upper Maastrichtian) includes similar chondrichthyans and a higher diversity of marine reptiles, including plesiosaurians (Aristonectes sp., Aristonectinae indet., and Elasmosauridae indet.), sea turtles (Pancheloniidae indet.) and diverse mosasaurs (Halisaurus sp., Tylosaurinae indet., and the first local occurrence of Plioplatecarpinae indet.). Throughout the Maastrichtian, the local marine vertebrates likely suffered a declination in abundance but a rise in diversity, with evidence of a marked alteration in middle levels of the trophic web during the upper Maastrichtian. This fauna shows a main influence from the northern hemisphere (especially from the Western Interior Sea), acquiring a more marked Weddellian influence during the end of the Maastrichtian. The studied material allows a better understanding of the Upper Cretaceous vertebrate marine fauna in lower latitudes of the southeastern Pacific.

Systematic and trophic diversity of protodidelphines (Mammalia, Marsupialia, Protodidelphidae): Evidence of a short time diversification during the onset of the Eocene

The Itaboraí Basin, municipality of Itaboraí, Rio de Janeiro, Brazil, preserved an early Eocene vertebrate assemblage. Among its representatives, Metatheria comprises its most diverse clade, with at least 29 genera and 43 species. Among large- to very large-sized taxa, protodidelphids are represented by Protodidelphis vanzolinii, P. mastodontoides, and Carolocoutoia ferigoloi. Protodidelphis mastodontoides was initially considered a different genus, Robertbutleria; however, the synonymy of Robertbutleria with Protodidelphis has never been tested. A phylogenetic analysis recovered Robertbutleria as the sister taxon of Carolocoutoia and not Protodidelphis. Robertbutleria and Carolocoutoia share the presence of rounded upper molars, evident bunodonty, rounded postmetacrista, U-shaped protocone, asymmetric placement of m4, obliquely oriented p1-3, and absence of diastemata. The analysis recovered that the dental features considered for the synonymy of Robertbutleria with Protodidelphis represented plesiomorphies for Protodidelphidae (e.g., sinuous crest between StB and StD, marked increase in the size of the molars from M/m1 to M/m3). Based on the results, an emended diagnosis of Protodidelphinae (the clade that includes Protodidelphis, Robertbutleria, and Carolocoutoia) is presented. Two principal component analyses (PCAs) recognized protodidelphine taxa in different morphospaces, indicating differential allometric and morphofunctional patterns. Protodidelphis was a generalized frugivore, Robertbutleria was a fibrous frugivore, and Carolocoutoia was a turgent frugivore. Moreover, the similar morphological and morphofunctional indexes of protodidelphines suggest a “short time” evolutionary diversification for this clade, and that trophic specializations do not necessarily require great morphological changes, allowing the sympatric co-existence of morphologically similar ingroup genera.

The first record of gars (Ginglymodi: Lepisosteidae) from the Upper Cretaceous of Bulgaria reveals a wider paleogeographic distribution of lepisosteids within the European Archipelago

The bony-fishes of the clade Lepisosteidae, commonly called ‘gars’ or ‘gar-fish’, are a lineage of proficient piscivores with evolutionary history spanning about 150 million years, which are today represented by two genera inhabiting the freshwater and brackish areas of southeastern North America, Central America, and Cuba. This was not the case during the Late Cretaceous when lepisosteids were more diverse and had much wider geographical distribution. Gar fossils, albeit very fragmentary, are a common component of the Upper Cretaceous freshwater and brackish vertebrate assemblages in Europe, yet all of the pre-upper Campanian records come from the western and central parts of the Late Cretaceous European Archipelago. Here we describe new lepisosteid material from Bulgaria, comprising nine teeth and three scales found at the uppermost Santonian–lowermost Campanian Vrabchov Dol vertebrate locality. These fossils represent the easternmost record of gars within the European Archipelago to date. Despite being found in a lagoonal to foreshore deposits, the paleontological content of the locality, the incompleteness and preservational state of the material, as well as the predominantly non-marine ecology of modern and fossils gars suggest that these fossils belong to fishes which inhabited more inland, freshwater environments. The Vrabchov Dol lepisosteids remains are the first record of gars in Bulgaria and one of the rare documented occurrences of Mesozoic osteichthyans in the country. This material expands the paleobiogeographic distribution of the Lepisosteidae within the European Archipelago.

The rise of dietary diversity in coral reef fishes.

Diet has been identified as a major driver of reef fish lineage diversification, producing one of the most speciose vertebrate assemblages today. Yet, there is minimal understanding of how, when and why diet itself has evolved. To address this, we used a comprehensive gut content dataset, alongside a recently developed phylogenetic comparative method to assess multivariate prey use across a diverse animal assemblage, coral reef fishes. Specifically, we investigated the diversification, transitions and phylogenetic conservatism of fish diets through evolutionary time. We found two major pulses of diet diversification: one at the end-Cretaceous and one during the Eocene, suggesting that the Cretaceous-Palaeogene mass extinction probably provided the initial ecological landscape for fish diets to diversify. The birth of modern families during the Eocene then provided the foundation for a second wave of dietary expansion. Together, our findings showcase the role of extinction rebound events in shaping the dietary diversity of fishes on present-day coral reefs.

Cross-boundary effects of human impacts on animal assemblages in the coastal zone

Human impacts on ecosystems often transcend ecosystem boundaries and environmental realms, complicating ecosystem assessment, conservation, and management. Whether and how different impacts affect ecosystems in distinct but adjacent domains remains untested in many settings, and is rarely tested concurrently at the same spatial scales. In this study, we quantified the effects of coastal urbanisation on the structure of terrestrial coastal vertebrate assemblages (including birds, reptiles and mammals using baited trail cameras) and marine surf zone fish assemblages (using baited underwater videography) at 100 sites along 50 km of beach in eastern Australia. Sites occurred along a gradient of intensities of urban land conversion in the hind dunes. While the effects of urbanisation on the species sampled were pervasive across both ecosystems, the area of urbanised land mattered more for the coastal vertebrates observed, while proximity to urbanised land was more important for the surf zone fish observed. Here, fewer individuals and species of coastal vertebrates were found at sites with a greater extent of urbanised land within 5 km. Conversely, fish assemblages were more diverse in the surf zones abutting urban areas and more abundant at sites approximately 150 m from urbanised land. The spatial properties of these landscapes, including proximity to headlands for coastal vertebrates and reefs for fish, modified the effects of urbanisation. Our findings suggest that urbanisation can have ecologically nuanced effects that are detectable across the land-sea boundary, and stress the importance of landscape context when assessing and conserving animal assemblages in and around coastal cities.

A tiny-sized Herpetotheriidae (Mammalia, Metatheria) from the Itaboraí basin (early Eocene), Brazil: Paleobiogeographic and systematic implications for Herpetotheriidae

The Itaboraí Basin, located in Itaboraí, Rio de Janeiro, Brazil, has preserved one of the most important early Eocene vertebrate assemblages of the Southern Hemisphere. Among its representatives, Metatheria comprises its most diverse group, with a minimum of 29 genera and 43 species. Considering this diversity, tiny and very small taxa are represented by Jaskhadelphyidae and closely related taxa, “Peradectoidea”, Sternbergiidae, Derorhynchidae, and an undescribed taxon with uncertain affinities, previously referred to as “cf. Armintodelphys”. Here, this last taxon is named Thylacopygmaeus oliveirai gen. et sp. nov.; it is distinguished by its extremely small size (inferred body mass less than 15 g) and in that its lower molars show the metaconid placed distally to the protoconid and a developed postentocristid. Two PCA analyses of T. oliveirai and other tiny-sized taxa from Itaboraí indicate that the new taxon exhibits distinctive morphometric and morphofunctional patterns compared to other sympatric tiny-sized taxa. The inclusion of T. oliveirai gen. et sp. nov. in a phylogenetic analysis recovered it as the sister taxon of Rumiodon, an early Oligocene herpetotheriid from Peru, based on the presence of a labiolingually compressed metaconid on m3 and a labiolingually compressed protoconid on m4. We group these two taxa within the Herpetotheriidae in a new clade, the Rumiodontinae nov. Contrary to a previous hypothesis, Thylacopygmaeus is not closely related to Armintodelphys. The results confirm the Paleogene occurrence of Herpetotheriidae in South America.

A Pleistocene Amphibian Assemblage of the Taurida Cave, Crimea

Six amphibian taxa are described within the Pleistocene vertebrate assemblage of the Taurida cave (Crimean Peninsula): Lissotriton sp., Strauchbufo raddei, Bufotes viridis, Rana cf. macrocnemis, Pelophylax ridibundus, and Pelophylax sp. The possible presence of second species of the genus Rana is suggested. Three of described species do not occur on the Crimean Peninsula currently, but apparently inhabited it during the Early Pleistocene. The ranid frogs in Crimea were taxonomically more divers in the Pleistocene than today. Strauchbufo raddei and Bufotes viridis come from different periods of sediment accumulation of the Taurida cave, during the Early Pleistocene and the late Middle Pleistocene, respectively. The presence of the Mongolian toad, Strauchbufo raddei, not previously reported from Crimea, confirms a wide distribution of this species during the Early Pleistocene of Eastern Europe. The Taurida cave represents the first Pleistocene amphibian assemblage of Crimea.

An earliest Triassic riparian ecosystem from the Bulgo Sandstone (Sydney Basin), Australia: palynofloral evidence of a high-latitude terrestrial vertebrate habitat after the end-Permian mass extinction

A landmark change in terrestrial ecosystems took place after the end-Permian mass extinction (EPME). This was marked by disappearance of the iconic latest Permian Glossopteris forests in Australian continental successions dated to 252.10 ± 0.06 Ma (mega-annum). Pioneering earliest Triassic spore-producing plants then spread following catastrophic wildfires, soil erosion and algal blooms. These ruderal plant communities were later replaced by vast Dicroidium ‘seed fern’ forests, which established under warm, seasonally dry conditions. By contrast, evidence of coeval vertebrate assemblages is scarce in Australia. The Bulgo Sandstone (Narrabeen Group) fossil biota in the Sydney Basin is, therefore, important as a rare example of associated plant and animal communities from the Early Triassic. The fossils include imprints and organic remains of lycopsid roots and attributed leaves (microphylls), Dicroidium and Lepidopteris foliage, and both erythrosuchid and smaller-bodied archosauromorphs, capitosaurians and other temnospondyls, actinopterygian fishes and sharks. Here, we undertake a palynofloral analysis of the vertebrate fossil-bearing bed within the Bulgo Sandstone to determine the assemblage age and palaeoenvironment. We identified a low-diversity miospore suite that is overwhelmingly dominated by lycopsids (42%), and especially quillworts (Isoëtales/Pleuromeiales) represented by Densoisporites and Aratrisporites. Bryophyte (moss), sphenopsid (horsetail) and ground fern spores are also present. Pollen (14%) comprises forms mainly associated with voltzialean conifers. The non-taeniate bisaccate Falcisporites (Alisporites) produced by Dicroidium is comparatively rare (3%). Based on this taxic composition, we correlate the vertebrate-bearing layer of the Bulgo Sandstone with the lower part of the Protohaploxypinus samoilovichii Oppel Zone and suggest a late Induan to early Olenekian age. Calculated sedimentation rates indicate that the 400 m of sediments between the top of the Vales Point Coal and the base of the Bulgo Sandstone were laid down within a time span of 40–400 ka (kilo-annum). Furthermore, the high portion of spores (37%) implies a parautochthonous organic accumulation that would have derived from local vegetation. This was likely riparian, with Dicroidium (and associated gymnosperm) cuticles (ca 20%) being over-represented because of a deciduous seasonal cycle. Notably, the Bulgo Sandstone accumulated on a high-palaeolatitude floodplain (ca 66–69°S) with dense vegetation flanking waterways that might have provided both shelter and forage for terrestrial vertebrates living less than 1 Ma after the EPME ecosystem collapse. Vivi Vajda* [vivi.vajda@nrm.se], Swedish Museum of Natural History, Svante Arrhenius väg 9, Stockholm 11414, Sweden; Benjamin P. Kear [benjamin.kear@em.uu.se], The Museum of Evolution, Uppsala University, Norbyvägen 16, Uppsala 75236, Sweden.

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.

Long-term assessment of resilience of avian assemblages following a major hurricane

Strong tropical cyclones directly devastate forest habitats and indirectly affect forest-dependent animals. Many forecast models suggest cyclone intensity and size will increase as a result of climate change, and cyclone frequency also may increase. Short-term effects of strong cyclones on vertebrate assemblages are well documented, but we know little about longer-term effects. From 1997 to 2013 we monitored avian assemblages at tropical forest in southern Belize, a forest that was largely destroyed by category 4 Hurricane Iris in October 2001. We found little change in recruitment or species richness, but evenness dropped markedly the first two sampling efforts after the hurricane and species turnover (β diversity) did not stabilize until 6–9 years afterward. Body condition dropped immediately after the hurricane passed but recovered quickly. That population size of resident tropical, but not Neotropical migrant, bird species dropped across our 17-year study highlights the potential urgency of altered cyclonic activity: on average, a hurricane strikes Belize once per decade, yet an increase in frequency, to say nothing of destructive power, could serve to erode extant species associations, lead to local extirpation of forest-dependent species, and create novel, transitory assemblages whose chief characteristic is instability.

Analysis of the Early Pleistocene small mammals from Pirro Nord 13 (Apricena, southern Italy) and their implications for reconstructing the palaeoenvironment of the early human occupation in Europe

The Pirro Nord quarry (Apricena, Foggia, southern Italy, 41°48′6″N, 15°23′5″ E) is a well-known palaeontological and archaeological locality comprising an abundant and diverse Early Pleistocene vertebrate assemblage of mammals, birds, amphibians, and reptiles related to the Late Villafranchian and Early Biharian mammal ages. In this study, we describe the small mammal assemblages (insectivores, rodents, and bats) excavated between 2010 and 2022 to reconstruct the palaeoenvironment surrounding the site using Habitat Weighting and the Bioclimatic model methods. The rodent assemblage comprises mostly Allophaiomys cf. ruffoi, Apodemus sp., and Hystrix refossa, whereas Eliomys cf. intermedius was reported for the first time. Insectivores includes Talpa gr. minor-caeca; Asoriculus sp.; Erinaceus praeglacialis; and Sorex sp. Bats are represented by Rhinolophus ferrumequinum, Rhinolophus gr. euryale-mehelyi, Myotis gr. myotis-blythii, Myotis sp., and Miniopterus schreibersii. Landscape reconstruction attested to the presence of a rich and diverse environment with open areas and forest patches surrounding the Pirro Nord 13 site. The climate was slightly colder than that of current times in the same area, with higher precipitation. The presence of different ecosystems near the sites constituted suitable conditions for the first human dispersion in Europe, as already revealed by evidence from Barranco León D, Atapuerca TE7–14, and Fuente Nueva 3 elsewhere on the Iberian Peninsula. The study of small mammal assemblages improves our understanding of the chronological boundaries of the human occupation of Pirro Nord 13, adding important information in the context of the first peopling of the Mediterranean region between 1.6 and 1.3 million years ago.

Osteology and phylogenetic relationships of the mid-Cretaceous neornithischian dinosaur Oryctodromeus cubicularis Varricchio, 2007

ABSTRACT The vertebrate assemblages of the Albian to Cenomanian Wayan Formation of southeastern Idaho and southwestern Montana’s coeval Vaughn Member of the Blackleaf Formation are dominated by the small, burrowing orodromine dinosaur Oryctodromeus cubicularis. Here, we describe in detail the osteology of Oryctodromeus based on new specimens from Idaho and Montana that add substantially to the preliminary description of the types from Montana, and provide a suite of additional diagnostic characters for the taxon: ilium with elongate preacetabular process; elongate cervical vertebra centra with an anteroposterior length 1.6 times the dorsoventral height; elongate dorsal vertebra centra with an anteroposterior length 1.4 times the dorsoventral height; more than 55 elongate caudal vertebrae enveloped in hypaxial and epaxial ossified tendons; and a femoral head on an elongate neck—similar to that of Koreanosaurus—projecting from the greater trochanter at about 35°. The tail, comprising two-thirds of the animal’s roughly 3 meters length, and associated tendon sheaths in the axial column indicate greater flexibility than previously supposed for ossified tendons or, alternatively, suggest that the Oryctodromeus burrows had separate, or multiple entrances and exits. The elongated and angled femoral head likely facilitated digging via a braced splayed-leg posture. Our phylogenetic analysis incorporates new characteristics and supports the monophyly of Orodrominae, a clade of neornithischian dinosaurs from the middle to Late Cretaceous of Asia and western North America that utilized burrowing.

A new metatherian (Mammalia) from the Itaboraí basin (Early Eocene), Brazil: Implications to trophic niche partitioning between large-sized “didelphoid-like” metatherians

The Itaboraí Basin, municipality of Itaboraí, Rio de Janeiro state, Brazil, preserved an Early Eocene vertebrate assemblage. Among its representatives, Metatheria comprises its most diverse clade, with a minimum of 29 genera and 43 species. Considering this diversity, large-sized taxa (based on didelphid standards, i.e., between 1 kg and 3.3 kg) are represented by Didelphopsis, Protodidelphis and Patene, each considered to have explored different trophic niches. However, the discovery of a new large-sized metatherian from this locality, here named Xenocynus crypticus gen. et sp. nov., indicates that the trophic complexity of Itaboraí’s metatherians could not be so well-defined. Xenocynus crypticus gen. et sp. nov. is identified by the presence of its reduced StD, long postmetacrista, short protocone, talonid's area much smaller than the one of trigonid, spaced paraconid and metaconid (bases are not in contact), molar series increasing in size from m1 to m4, deep maxillary pits between upper molars, and robust symphysis. We included Itaboraidelphys camposi, X. crypticus gen. et sp. nov. and other large-sized taxa in two PCA analyses, the first considering morphometric measurements and the second considering some morphofunctional indexes, to test their placement in morphospace. Our analyses indicated that these taxa exhibit distinctive morphometric and morphofunctional patterns, suggesting low trophic niches overlapping between them. The results indicate that X. crypticus gen. et sp. nov. was a generalized carnivore (insectivory-carnivory), more specialized than the insectivorous/omnivorous Itaboraidelphys camposi, but less specialized than the larger Patene simpsoni, a carnivorous taxon.

The first cetacean from the early Oligocene of the SW German Mainz Basin: a probable cheek tooth of a mysticete (Mammalia: Cetacea)

AbstractDespite two centuries of fossils collecting, no cetacean remains from the Oligocene marine deposits of the Mainz Basin (western Germany) have ever been reported. Here, we describe a possible mysticete tooth from the sand pit of Eckelsheim, which exposes high energy deposits belonging to the Rupelian Alzey Formation. The latter has yielded a rich assemblage of vertebrates and invertebrates, but so far, only one marine mammal in the form of the sirenian Kaupitherium. The whale tooth in some ways resembles the m2 of Llanocetus from the latest Eocene of Seymour Island, Antarctica. If the find from the Mainz Basin is not a regionally evolved form, Llanocetus, which is known from the South Atlantic, could have migrated through the Atlantic realm during the early Oligocene. It cannot be excluded that the tooth represents a more widely occurring lineage, neither endemic nor necessarily related to llanocetids, that—given the generally poor Rupelian record—has not been well documented yet.

Well‐drained floodplain taphonomic mode of Late Pleistocene vertebrates from northwestern Argentina

ABSTRACTThe vertebrate assemblage recovered from the Toropí/Yupoí Formation (Late Pleistocene) in the Arroyo Toropí area, Bella Vista (Corrientes Province, Argentina), has been subjected to taphonomic evaluation. The fossil‐bearing levels have been dated to ~53 ka (MIS 3) based on Optically Stimulated Luminescence dating. This assemblage primarily comprises mammal remains, with a notable prevalence of herbivorous megamammals. Also, reptiles and birds have been documented. Sedimentological analysis suggests that the skeletal remains were preserved within a floodplain environment influenced by the dynamics of the adjacent fluvial system, and taphonomic features observed in the assemblage support this interpretation. The assemblage resulted from the deposition of disarticulated mammal remains and local dispersion over a relatively short period. Rapid burial is evident, but several processes such as weathering and breakage have contributed to the observed patterns. The loss of several skeletal elements within the assemblage may be attributed to sporadic water flows occurring on the floodplain. During the post‐burial stage, the specimens were affected by diagenetic processes, including filling, impregnation, deformation and breakage. In summary, the taphonomic evaluation of the Toropí/Yupoí Formation offers valuable comparison with other fossil fluvial assemblages. This research contributes to our understanding of the processes and environmental conditions that shaped this Late Pleistocene ecosystem.

Early Cretaceous continental sedimentatary environments, palaeogeography and biota of southeastern Western Siberia

Abstract The Ilek Formation was distinguished by Ragozin in 1936 in the SE of Western Siberia, as a sequence of continental deposits accumulated in the alluvial and lacustrine environments, dating Barremian–Early Albian. At the end of the twentieth century a series of sites, comprising rich and diverse Early Cretaceous vertebrates, was discovered, which forced an intensive comprehensive research of the Ilek Formation. The stratotype section of the Bolshoi Ilek represents an abnormal section of the Ilek Formation, comprising the deposits of prodelta, delta front and mouth bars. Three regions within the area of the Ilek Formation reflect the evolution of the fluvial system. The eastern region represents the oldest part of the section, preliminarily dated to the Barremian based on spore and pollen analysis in addition to lithological characteristics. The western region was probably deposited during ocean anoxic event (OAE) 1a. The central region represents the final stage of the tectonic cycle, deposited within the environments of the calm plain river and fluvial delta. The vertebrate assemblages distinguished for the Kiya and Bolshoi Kemchug basins have specific features, which can support the heterochrony of the Ilekian deposits.

Multiproxy approach to reconstruct the climate and environment of a new late Middle Pleistocene vertebrate site in northwestern Italy

The Moleto site (Ottiglio, AL, Piemonte, Italy) was discovered in the 1990s in an abandoned quarry carved into a Burdigalian–Langhian carbonate succession called Pietra da Cantoni. Sediment collection in three closely spaced fissures provided a rich vertebrate association whose age can be constrained to the late Middle Pleistocene on the basis of the presence of the extinct water vole Arvicola mosbachensis and its enamel characteristics (SDQ values ranging from 100 to 130). The very similar faunal content, evidenced by the common presence of Arvicola mosbachensis and its similar SDQ values, is indicative of a coeval deposition of the fillings of the three fissures. The vertebrate assemblage is represented by 30 taxa, including amphibians, squamate reptiles, birds, and mammals. Interestingly, a diverse fish assemblage from the embedded sediments of the Miocene Pietra da Cantoni has been found in the fissure fillings. We present here a multi-method approach using the small vertebrate assemblages (rodents, insectivores, amphibians, and squamate reptiles) from Moleto to characterize the environment and climate of the site. In order to reconstruct the palaeoenvironmental and palaeoclimatic conditions, we applied the Mutual Ecogeographic Range using UDA-ODA technique, the Bioclimatic Model, the Habitat Weightings, and the Quantified Ecology methods. The results revealed a landscape dominated by woodland habitats with presence of open humid meadows, under temperate and moist climatic conditions, although somewhat colder and drier than today. According to all evidence, the associations from Moleto would correspond to the interglacial MIS 7.

Fossil marine vertebrates (Chondrichthyes, Actinopterygii, Reptilia) from the Upper Cretaceous of Akkermanovka (Orenburg Oblast, Southern Urals, Russia)

Upper Cretaceous coastal marine deposits are widespread in the Southern Urals with a number of marine vertebrates previously reported from this region. However, previous studies on the vertebrate faunas in this region often lack detailed taxonomic descriptions and illustrations, rendering comparisons to other faunal assemblages difficult. A new diverse vertebrate assemblage comprising cartilaginous and bony fishes, as well as marine reptiles, is described here from the Orenburg region near Akkermanovka (Southern Urals, Russia). Thirty five taxa are identified, including three holocephalans (Elasmodus sp., Ischyodus yanschini, Chimaeroid indet.), two hybodontiform sharks (Meristodonoides sp., cf. Polyacrodus sp.), 17 neoselachians (Paraorthacodus cf. andersoni, Paraorthacodus sp., Synechodus sp., Cederstroemia nilsi, Acrolamna acuminata, Archaeolamna ex gr. kopingensis, Cretalamna sarcoportheta, Cretoxyrhina mantelli, Eostriatolamia segedini, E. venusta, Hispidaspis horridus, H. cf. gigas, Pseudocorax laevis, Pseudoscapanorhynchus compressidens, Scapanorhynchus rhaphiodon, Squalicorax kaupi, Ptychodus rugosus), a holostean (Lepisosteidae indet.), nine teleosts (Protosphyraena sp., Saurodontidae indet., cf. Pachyrhizodus sp., Pachyrhizodontidae indet., Enchodus petrosus, E. ferox, E. cf. gladiolus, E. spp., Alepisauroidei indet.), two plesiosaurs (Polycotylidae indet., Plesiosauria indet.), and one mosasaurid (Tylosaurinae indet.). Based on the faunal assemblage, a Santonian–?early Campanian age is proposed. Lamniform sharks are the best represented group in terms of taxic diversity and relative abundance, probably reflecting the peak in diversity this group experienced following the Cenomanian radiation in the Late Cretaceous. The faunal assemblage of Akkermanovka exhibits significant taxonomic overlaps with assemblages reported from Asia and North America, but not from Southern Hemisphere continents, indicating east–west dispersal of several marine taxa during the Late Cretaceous.