Hasil untuk "Paleontology"

Sina F. J. Dupuis, Jordan Bestwick, Dennis M. Hansen et al.

Abstract The sauropodomorph Plateosaurus is one of the best-known dinosaurs from Europe due to the large numbers of articulated skeletons discovered from bonebed horizons in Switzerland and Germany. Plateosaurus exhibits high degrees of developmental plasticity, which makes investigations of specimen life-histories from gross morphology alone difficult. Furthermore, comparatively few specimens have been rigorously examined for possessing any evidence of pathology, i.e., injury or disease, that could provide insight into how these dinosaurs lived. Here, we provide an osteological description of a nearly complete Plateosaurus trossingensis (excavation ID SMF 18.1, collection NMZ 1000001) from the Late Triassic Klettgau Formation from Frick, Switzerland, with an unusual pathology in its right scapula and proximal portion of the right humerus. We also perform histological analyses on two dorsal ribs to investigate the relative ontogenetic stage and life history of the specimen and investigate the morphology and aetiology of its scapula-humerus pathology using Micro-Computed Tomography and comparisons with a previously undescribed Plateosaurus from Frick (SMF 11.4; comprising left and right radii and ulnae) that exhibits pathological tissues. We infer that NMZ 1000001 was an adult of around 23–25 years of age when it died. We estimate a total body length of around 7.7 m, making NMZ 1000001 one of the largest known specimens from Frick and an above average-sized adult for the species overall. The scapula-humerus pathology is characterised by highly rugose surface textures, possible element fusion and extensive remodelling of internal bone structures. We infer the pathology to be a chronic case of osteomyelitis (bone tissue infection). Based on the size and extent of the infected area it is likely one of most advanced cases known from the fossil record. We further document the process of producing an exhibit with a museum-grade life reconstruction based on the pathological fossil.

KONGRAILATPAM MILANKUMAR SHARMA, MARTIN EZCURRA, RAGHAVENDRA PRASAD TIWARI et al.

The Panchet Formation of northeastern India preserves an Induan (earliest Triassic) vertebrate assemblage with only one valid archosauromorph species, the proterosuchid Samsarasuchus pamelae. Two other archosauromorph species have been named for this unit: “Ankistrodon indicus” and “Teratosaurus(?) bengalensis”. “Ankistrodon indicus”, based on a fragment of maxilla with two partial teeth, is indistinguishable from other proterosuchid species and is considered a nomen dubium. “Teratosaurus(?) bengalensis” is represented by an isolated, almost complete tooth that was distinguished from “Ankistrodon indicus” in the presence of mesial denticles. “Teratosaurus(?) bengalensis” is also indistinguishable from other valid proterosuchid species and considered likely a nomen dubium. However, it remains unresolved if “Teratosaurus(?) bengalensis” represents a second Panchet archosauromorph species different from Samsarasuchus pamelae and “Ankistrodon indicus” because the presence of mesial denticles cannot be determined in these species due to their incompleteness. Here we describe two new Panchet Proterosuchidae specimens collected from the same locality as the holotypes of the three above-mentioned species. These new specimens are maxillary fragments and one of them has almost complete teeth with mesial denticles on the apical portion of the crowns, as in “Teratosaurus(?) bengalensis.” The rest of their morphology is congruent with that of Samsarasuchus pamelae and “Ankistrodon indicus.” As a result, the specimens reported here expand our anatomical knowledge of the Panchet archosauriform assemblage and indicate that there is no current evidence for the presence of more than one valid archosauromorph species in the Panchet Formation.

Timothy R. Smithson, Marcello Ruta, Jennifer A. Clack

Recent discoveries in the Scottish Borders have greatly expanded our knowledge of post-Devonian tetrapods. Six new taxa have been named and briefly described so far. One of these, Ossirarus kierani, is represented by a single specimen from the coastal section of the Tournaisian Ballagan Formation at Burnmouth. It comprises the disarticulated bones of the posterior half of the skull, the anterior portion of the axial skeleton, and parts of the pectoral girdle and forelimbs. It is relatively small, with an estimated skull length of 54 mm. Like some Devonian tetrapods it has a preopercular and a lateral line system represented by pores. It shares with embolomeres, a tabular-parietal suture, an intertemporal and a long tabular horn. The gastrocentrous vertebrae resemble those of Caerorhachis and the brachial foramen pierces the humerus through the posterior edge, as in Mesanerpeton. Phylogenetic analyses place Ossirarus on the tetrapod stem, crownward of some – but not all – Devonian taxa. The topology of the tetrapod stem suggests that numerous lineages of Carboniferous tetrapods extended back into the Devonian.

Ida Bonnevier Wallstedt, Peter Sjövall, Ben Thuy et al.

A partial ichthyosaur skeleton from the Toarcian (Lower Jurassic) bituminous shales of the ‘Schistes Carton’ unit of southern Luxembourg is described and illustrated. In addition, associated remnant soft tissues are analyzed using a combination of imaging and molecular techniques. The fossil (MNHNL TV344) comprises scattered appendicular elements, together with a consecutive series of semi-articulated vertebrae surrounded by extensive soft-tissue remains. We conclude that TV344 represents a skeletally immature individual (possibly of the genus <i>Stenopterygius</i>) and that the soft parts primarily consist of fossilized skin, including the epidermis (with embedded melanophore pigment cells and melanosome organelles) and dermis. Ground sections of dorsal ribs display cortical microstructures reminiscent of lines of arrested growth (LAGs), providing an opportunity for a tentative age determination of the animal at the time of death (>3 years). It is further inferred that the exceptional preservation of TV344 was facilitated by seafloor dysoxia/anoxia with periodical intervals of oxygenation, which triggered phosphatization and the subsequent formation of a carbonate concretion.

M. Vinnepand, P. Fischer, U. Hambach et al.

<p>The study of geological archives of dust is of great relevance as they are directly linked to past atmospheric circulation and bear the potential to reconstruct dust provenance and flux relative to climate changes. Among the dust sinks, loess–palaeosol sequences (LPSs) represent the only continental and non-aquatic archives that are predominantly built up by dust deposits close to source areas, providing detailed information on Quaternary climatic and terrestrial environmental changes. Upper Pleistocene LPSs of western central Europe have been investigated in great detail showing their linkage to<span id="page164"/> millennial-scale northern hemispheric climate oscillations, but comprehensive data on dust composition and potential source–sink relationships as well as inferred past atmospheric circulation patterns for this region are still fragmentary.</p> <p>Here, we present an integrative approach that systematically combines sedimentological, rock magnetic, and bulk geochemical data, as well as information on Sr and Nd isotope composition, enabling a synthetic interpretation of LPS formation. We focus on the Schwalbenberg RP1 profile in the Middle Rhine Valley in Germany and integrate our data into a robust age model that has recently been established based on high-resolution radiocarbon dating of earthworm calcite granules. We show that Schwalbenberg RP1 is subdivided into a lower section corresponding to late oxygen isotope stage 3 (OIS; <span class="inline-formula">∼</span> 40–30 ka) and an upper section dating into the Last Glacial Maximum (LGM; <span class="inline-formula">∼</span> 24–22 ka), separated by a major stratigraphic unconformity. Sedimentological proxies of wind dynamics (<span class="inline-formula"><i>U</i></span> ratio) and pedogenesis (finest clay) of the lower section attest to comparable and largely synchronous patterns of northern hemispheric climatic changes supporting the overall synchronicity of climatic changes in and around the North Atlantic region. The anisotropy of magnetic susceptibility (AMS) reveals a clear correlation between finer grain size and increasing AMS foliation within interstadials, possibly owing to continuous accumulation of dust during pedogenic phases. Such a clear negative correlation has so far not been described for any LPS on stadial–interstadial scales.</p> <p>Distinct shifts in several proxy data supported by changes in isotope composition (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="3e742fac50d9344ff94fdf71fe05f27c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="egqsj-72-163-2023-ie00001.svg" width="49pt" height="15pt" src="egqsj-72-163-2023-ie00001.png"/></svg:svg></span></span> and <span class="inline-formula"><i>ε</i></span>Nd) within the lower section are interpreted as changes in provenance and decreasing weathering simultaneously with an overall cooling and aridification towards the end of OIS 3 (after <span class="inline-formula">∼</span> 35 ka) and enhanced wind activity with significant input of coarse-grained material recycled from local sources related to increased landscape instability (after <span class="inline-formula">∼</span> 31.5 ka). We find that environmental conditions within the upper section, most likely dominated by local to regional environmental signals, significantly differ from those in the lower section. In addition, AMS-based reconstructions of near-surface wind trends may indicate the influence of north-easterly winds beside the overall dominance of westerlies. The integrative approach contributes to a more comprehensive understanding of LPS formation including changes in dust composition and associated circulation patterns during Quaternary climate changes.</p>

R. R. Schoch, R. R. Schoch

<p>Eryopid temnospondyls were large apex predators in Carboniferous and Permian stream and lake habitats. The eryopid life cycle is exemplified by <i>Onchiodon labyrinthicus</i> from Niederhäslich (Saxony, Germany), which is represented by numerous size classes from small larvae to heavily ossified adults. Morphometric and principal component analyses provide new insights into ontogenetic changes in <i>O. labyrinthicus</i>, and comparison with adults of other eryopids documents phylogenetic patterns in the occupation of morphospace.</p> <p>Compared with small specimens of <i>Sclerocephalus</i> spp., immature <i>O. labyrinthicus</i> occupies a neighboring but much larger space, corresponding to a broader range of variation. Adults of <i>Actinodon frossardi</i> map with some juveniles of <i>O. labyrinthicus</i>, whereas other juveniles of the latter lie close to adults of <i>O. thuringiensis</i>, <i>Glaukerpeton avinoffi</i> and <i>Osteophorus roemeri</i>.</p> <p>Morphospace occupation of adult eryopids is partly consistent with cladistic tree topology, which gives the following branching pattern: <i>Actinodon frossardi</i> forms the basalmost eryopid, followed by <i>Osteophorus roemeri</i>, <i>Glaukerpeton avinoffi</i> and the genus <i>Onchiodon</i> (<i>O. labyrinthicus</i> <span class="inline-formula">+</span> <i>O. thuringiensis</i>); then <i>Clamorosaurus nocturnus</i>; and finally the monophyletic genus <i>Eryops.</i> The presumably juvenile skull of <i>Eryops anatinus</i> falls well outside the domains of both adult eryopids and immature <i>O. labyrinthicus</i>, showing a unique combination of juvenile and adult features. Instead, <i>Onchiodon langenhani</i> and the Ruprechtice specimens referred to <i>O. labyrinthicus</i> map within the domain of immature <i>O. labyrinthicus</i>.</p> <p>Raised levels of variation in <i>O. labyrinthicus</i> coincide with evidence of a stressed habitat, in which limiting factors were fluctuating salinity, absence of fishes, enhanced competition and seasonal algal blooms. The documented broad variation was possibly caused by developmental plasticity responding to fluctuations in lake hydrology and nutrients in this small, short-lived water body.</p>

Ekaterina V. Doronicheva

In the paper, the author discusses the Middle Palaeolithic workshop sites on raw material sources and bifacial production in the north-western Caucasus. Five Middle Palaeolithic camp-workshop-type sites located directly on raw material sources are known in the region, including Monasheskaya and Barakaevskaya caves, and open-air sites of Hadjoh-2, Besleneevskaya-1, and, probably, Il'skaya II. These all are multi-layered sites located directly on raw material sources. Two different types of camp-workshops were defined: active habitation camp-workshops and short-term camp-workshops, which are characterized by specific features. Besides the presence of tool forms that have analogies in the local Micoquian assemblages, these sites show similar technological peculiarities characteristic to local Micoquian, such as the non-Levallois, non-laminar, and non-faceted flaking technology.

Daniel JG Lahr

The phylogenetic paradigm of eukaryotic evolution has changed dramatically over the past two decades, with profound reflections on the understanding of life on earth. Arcellinida testate (shelled) amoebae lineages represent some of the oldest fossils of eukaryotes, and the elucidation of their phylogenetic relationships opened a window to the distant past, with important implications for understanding the evolution of life on earth. This four-part essay summarises advances made in the past 20 years regarding: (i) the phylogenetic relationships among amoebae with shells evolving in concert with the advances made in the phylogeny of eukaryotes; (ii) paleobiological studies unraveling the biological affinities of Neoproterozoic vase-shaped microfossils (VSMs); (iii) the interwoven interpretation of these different sets of data concluding that the Neoproterozoic contains a surprising diversity of organisms, in turn demanding a reinterpretation of the most profound events we know in the history of eukaryotes, and; (iv) a synthesis of the current knowledge about the evolution of Arcellinida, together with the possibilities and pitfalls of their interpretation.

C. P. A. Smith, N. H. Landman, J. Bardin et al.

Abstract Ammonite soft body remains are rarely preserved. One of the biggest enigmas is the morphology of the ammonite brachial crown that has, up till now, never been recovered. Recently, mysterious hook-like structures have been reported in multiple specimens of Scaphitidae, a large family of heteromorph Late Cretaceous ammonites. A previous examination of these structures revealed that they belong to the ammonites. Their nature, however, remained elusive. Here, we exploit tomographic data to study their arrangement in space in order to clarify this matter. After using topological data analyses and comparing their morphology, number, and distribution to other known cephalopod structures, in both extant and extinct taxa, we conclude that these hook-like structures represent part of the brachial crown armature. Therefore, it appears that there are at least three independent evolutionary origins of hooks: in belemnoids, oegospids, and now in ammonites. Finally, we propose for the first time a hypothetical reconstruction of an ammonite brachial crown.

Blaine W. Schubert, Joshua X. Samuels, James C. Chatters et al.

Ongoing investigation of peccary remains from fossiliferous deposits in the Yucatán resulted in re-examination of previously identified tayassuid fossils from the region. This included the recently described new genus and species of peccary, 'Muknalia minima', which is based on a dentary from Muknal Cave near Tulum, Quintana Roo, Mexico. Diagnostic characters of this taxon include a concave notch along the caudal edge of the ascending ramus and a ventrally directed angular process. Our assessment of the holotype indicates that these characteristics are not a reflection of the original morphology, but are instead the result of breakage and polishing of the posterior aspect of the dentary. Measurements and intact morphological features indicate the Muknal Cave specimen belongs to the extant collared peccary, 'Pecari tajacu'.

Luvsantseden Uranbileg, Sukhbat Purevsuren, Byambaa Purevsuren et al.

The research area is located in the territory of Khatanbulag soum, Dornogovi province, in the Great Govi Province (coordinates: 108°25'39.04"E and 43°10'11.43"N). Here, the authors studied the composition of sediments that had previously been classified as Lower Cretaceous Khukhteeg Formation, forming Mt. Ergel-Khaliv during earlier mapping work. The authors revealed fossils of faunas and floras, processing some data of biostratigraphic survey works taken on fossil-bearing sediments of the area. The fieldwork was conducted in April 2019 by researchers from the Institute of Paleontology, Mongolian Academy of Sciences. The area is very rich in fossils of mollusca, therefore, the local communities named it Dun-Ovoo (Conch hill). During the previous studies, the sediments outcropping around the Ergel-Khaliv were classified as Khukhteeg Formation (K1ht, Aptian-Albian) based on lithological characteristics and comparing them to the type section of the Khukhteeg Formation sediments. Our research revealed biostratigraphic basements and recorded previous data of collected fossils two types of mollusca; we have studied plant fossils, turtles, ostracods, fish and dinosaur bones had been revealed at first in that area. The results of the research work, the fossils that found in the mountain, were amended by more and new types and families of fauna and flora and their constituents. These new findings were helpful in the precise determination of the age of the sediments and provided some information on the paleoenvironmental conditions of the sedimentation period.

Matías A. Armella, Daniel A. García-López, M. Judith Babot et al.

Notoungulates represent the most taxonomically diverse and temporally and geographically widespread group among South American native ungulates. Here, we analyze anatomical and systematic aspects of proximal tarsal bones recovered from the Lower and Upper Lumbrera formations (middle and late middle Eocene) in northwestern Argentina. We provide detailed descriptions, comparisons, and infer foot stances and range of movements for the taxa implicated. Material studied includes astragali belonging to the oldfieldthomasiid Colbertia lumbrerense (Lower Lumbrera Formation), a set of proximal tarsals referred as Typotheria indet. (Lower Lumbrera Formation), and tarsals (also including navicular and cuboid) of the informal taxon “Campanorco inauguralis” (Upper Lumbrera Formation). The comparison of the tarsals of Colbertia lumbrerense (middle Eocene of Argentina) with Colbertia magellanica (early Eocene of Brazil) reveals several differences including variations on the development and arrangement of articular facets, and the size of the dorsal astragalar foramen in the Argentinean species. The specimen of Typotheria indet. shows morphological affinities with basal interatheriid taxa. However, its larger size contrasting with the overall small body sizes of Eocene interatheriids precludes an indisputable taxonomic assignment. Concerning “Campanorco inauguralis”, our observations indicate that there is no morphological evidence for a close phylogenetic relationship with Mesotheriidae. It presents a “reversed alternating tarsus” condition, which is also observed in Leontiniidae, “Notohippidae”, Toxodontidae, and some typotherians. However, the spectrum of singularities exhibited by this form precludes the assessment of its relationships in the context of the Paleogene radiation of Typotheria and it is necessary to extend the comparison to Eocene notoungulates. Finally, in a morphofunctional context a plantigrade foot posture is inferred for the specimens here reported. These observations have the potential to provide functional proxies for paleoecological reconstructions to be applied to the study of the early radiation of these notoungulate faunas.

F. Scholze, V. Golubev, G. Niedźwiedzki et al.

Abstract. The Moscow Syneclise on the East European Platform is an important area for the study of the continental biota of late Permian to Early Triassic age in continuous sections. This study attempts a taxonomic description of the late Permian conchostracan fauna of this area. The rich, new material was collected, bed by bed, during geological and paleontological excavations of lacustrine and fluvial deposits of the Obnora Formation and Vokhma Formation of the late Permian Zhukovian Regional Stage near the towns of Vyazniki and Gorokhovets. The conchostracan fauna of the Zhukovian Regional Stage consists predominantly of Pseudestheria and less frequently of Palaeolimnadiopsis. In the earliest Triassic Vokhmian Regional Stage, a more diverse fauna including Euestheria, Magniestheria, Cornia, Palaeolimnadiopsis, and Rossolimnadiopsis was already recorded. The preliminary taxonomic determination of the pseudestheriids from the Zhukovian Regional Stage is intended to serve as a prerequisite for future studies of late Permian conchostracan biostratigraphy on the regional to interregional scale.

Harry F. Filkorn

An extensive, detailed compilation of the known occurrences and described species of Cretaceous scleractinian corals in the country of Mexico, based almost entirely on published scientific literature, is presented for the first time. Cretaceous corals have been reported from more than 170 localities in more than 200 published studies dating from at least as early as 1839. Unfortunately, relatively few of these 200 publications actually described coral species: the entire research history on Mexican Cretaceous coral systematic paleontology is contained in only 16 studies. A total of 116 coral species have been described from these occurrences, inclusive of unnamed coral species and with previously suggested synonymies taken into consideration. Overall the coral occurrences span nearly the entire Cretaceous Period, from the Berriasian through the Maastrichtian, but at least 60 percent of them are from the Early Cretaceous. Furthermore, the vast majority (about 90 percent) of the total number of Mexican Cretaceous coral species are known from the Early Cretaceous. Based on these data, it seems likely that many of the Cretaceous corals of Mexico are still unknown. The detailed review of the literature on Mexican Cretaceous corals presented in this study establishes a modern foundation for future investigations of the paleobiogeography and systematic paleontology of the members of this significant group of reef-building organisms.

Samuel Zamora, Marcos Aurell, Margaret Veitch et al.

Post-Palaeozoic crinoids from northeast Spain ranging from the Ladinian (Middle Triassic) to the Ilerdian (lower Ypresian, early Eocene) are documented. Here we provide the first attempt to reconstruct the environmental distribution of these crinoids based on relatively complete material (mostly cups). Triassic forms are dominated by encrinids from outer carbonate ramps. Late Jurassic crinoids are dominated by cyrtocrinids, comatulids, millericrinids, and isocrinids, occurring either on sponge mounds and meadows or on soft substrates within middle to outer carbonate ramps. Aptian (Early Cretaceous) forms include nearly complete isocrinids which are found in extremely shallow environments represented by bioclastic carbonates and interspersed oyster-rich layers. Other Aptian occurrences come from more distal and deep environments and are composed solely of comatulids. Albian forms are dominated by cyrtocrinids and isocrinids associated with coral reefs. Late Cretaceous and Eocene crinoids include mostly bourgueticrinids (Comatulida) that are found either in outer ramp facies or associated with mid-ramp reef complexes. The later corresponds to one of the shallowest occurrence of bourgueticrinids in the Cenozoic. The palaeoecological data for fossil crinoids of northeast Spain contributes to reconstructing the history of the bathymetric distribution of articulate crinoids, supporting the idea that stalked crinoids were able to inhabit a wide range of shallow marine environments in the late Mesozoic and early Cenozoic.

Maria Eugenia Leone Gold, Akinobu Watanabe

Abstract Background In comparative neurobiology, major transitions in behavior are thought to be associated with proportional size changes in brain regions. Bird-line theropod dinosaurs underwent a drastic locomotory shift from terrestrial to volant forms, accompanied by a suite of well-documented postcranial adaptations. To elucidate the potential impact of this locomotor shift on neuroanatomy, we first tested for a correlation between loss of flight in extant birds and whether the brain morphology of these birds resembles that of their flightless, non-avian dinosaurian ancestors. We constructed virtual endocasts of the braincase for 80 individuals of non-avian and avian theropods, including 25 flying and 19 flightless species of crown group birds. The endocasts were analyzed using a three-dimensional (3-D) geometric morphometric approach to assess changes in brain shape along the dinosaur-bird transition and secondary losses of flight in crown-group birds (Aves). Results While non-avian dinosaurs and crown-group birds are clearly distinct in endocranial shape, volant and flightless birds overlap considerably in brain morphology. Phylogenetically informed analyses show that locomotory mode does not significantly account for neuroanatomical variation in crown-group birds. Linear discriminant analysis (LDA) also indicates poor predictive power of neuroanatomical shape for inferring locomotory mode. Given current sampling, Archaeopteryx, typically considered the oldest known bird, is inferred to be terrestrial based on its endocranial morphology. Conclusion The results demonstrate that loss of flight does not correlate with an appreciable amount of neuroanatomical changes across Aves, but rather is partially constrained due to phylogenetic inertia, evident from sister taxa having similarly shaped endocasts. Although the present study does not explicitly test whether endocranial changes along the dinosaur-bird transition are due to the acquisition of powered flight, the prominent relative expansion of the cerebrum, in areas associated with flight-related cognitive capacity, suggests that the acquisition of flight may have been an important initial driver of brain shape evolution in theropods.

Leonardo M. Carneiro, Édison Vicente Oliveira

Zeusdelphys complicatus is one of the most enigmatic metatherians from the Itaboraí Basin. The type and only known specimen was previously regarded as the upper dentition of Eobrasilia; an M4 of a new taxon; an M3 of a Kollpaniidae (now regarded as a group of “condylarths”); a probable M1 of an incertae sedis taxon; and as an M1 of a Protodidelphidae. Herein, we present a morphological review of the dental structures of Zeusdelphys complicatus, presenting new interpretations and comparing it with other North and South American taxa. We also perform a phylogenetic analysis in order to test the affinities of Zeusdelphys and the validity of most studied characters. The results recovered Zeusdelphys complicatus as more closely related to Hatcheritherium alpha than to any other metatherian. Glasbiidae were recovered as the sister lineage of Protodidelphidae within Didelphimorphia, as true marsupials. Ectocentrocristus was recovered as the sister taxon of Zeusdelphys + Hatcheritherium, as a Hatcheriformes. The analysis recovered this suborder as an independent lineage from Polydolopimorphia, being more closely related to “Alphadontidae”. The affinities with Protodidelphidae are a result of convergent evolution, as Zeusdelphys is more closely related to Hatcheritherium alpha from the Late Cretaceous of North America. The results support a North American origin for Hatcheriformes. The presence of strong sea-level lowstands and islands in the Caribbean Plate during the Late Cretaceous provide valid data to support a faunal interchange between Americas during the latest Late Cretaceous. Based on the results, Zeusdelphys represents a South American early Eocene surviving Hatcheriformes.

N. Akulov, A. Frolov, I. Mashchuk et al.

G. Mayr, R. Scofield

B. Granier, Nadine Roulance, C. Emig et al.

Carnets de Geologie - Notebooks on Geology, an open-access geoscience journal published electronically, which concentrates on stratigraphy, sedimentology and paleontology.