This study presents a high-resolution biostratigraphic analysis of a nearly 30 km long platform-to-slope transect on the southern margin of the Vercors Urgonian platform, based on detailed ammonite data. The primary objective is to refine the chronostratigraphic framework of the upper Barremian Urgonian series and to reassess the timing and significance of marlstone intercalations within the carbonate succession. For this purpose, more than 100 ammonite specimens were collected along the transect at various stratigraphic levels. All standard ammonite biozones and most subzones of the upper Barremian have been confidently identified, allowing precise dating of key sedimentary and stratigraphic events. A central issue concerns the platform-to-basin correlation of Paquier’s so-called “Heteroceras marlstone”, which conflates two distinct marly intercalations of different ages under a single term. We distinguish two major marlstone complexes – (1) Ambel / Font Froide – La Béguère and (2) Pas de la Couronne / La Révolte / Lower Orbitolina Beds – that have been variously attributed to, or confused with, the Heteroceras marlstone by Paquier, his followers, and his detractors. Based on ammonite biostratigraphy, only the second complex can be confidently correlated with the Heteroceras marlstone. Together with the Upper Orbitolina Beds, these intervals are interpreted as recording three successive ingressions, the final one marking the ultimate demise of the Urgonian platform near the Barremian–Aptian boundary. This revised biostratigraphic framework clarifies long-standing stratigraphic ambiguities, strengthens regional correlations, and provides new insights into the timing and mechanisms of Lower Cretaceous carbonate platform evolution in the western Tethys.
Libro de resúmenes de las XXXVIII Jornadas Argentinas de Paleontología de Vertebrados, que tuvieron lugar en la Ciudad de San Luis (San Luis, Argentina) del 21 al 23 de mayo de 2025.
A taxonomic study of four tooth genera of euselachian sharks from the Ladinian–Carnian interval of the Guizhou and Yunnan Provinces, South China is presented. They include one euselachian shark of uncertain affinity, two indeterminate neoselachian sharks and one potential hexanchid shark. These four taxa display non-durophagous feeding behaviour, including grasping-swallowing, grasping, tearing and cutting strategies. High-resolution micro-CT scans and 3D reconstructions reveal that Euselachii gen. et sp. indet. and Neoselachii gen. et sp. indet. 1 possess orthodont teeth. Euselachii gen. et sp. indet. exhibits a prominent longitudinal vascular canal, but lacks an ascending pulp cavity, while Neoselachii gen. et sp. indet. 1 features two longitudinal vascular canals and a vascular cavity that ascends into the main cusp. To our knowledge, this study provides the first three-dimensional documentation of dental vascularisation in Triassic chondrichthyans.
Alexis Gerbe, Christian Bartel, Carolin Haug
et al.
Harvestmen are common elements of the modern-day fauna, however, the fossil record of harvestmen is sparse, with only about 50 fossil species in comparison to almost 7000 extant species. A new fossil harvestman (Arachnida, Opiliones) is described here, from Eocene Baltic amber. While having common harvestmen features such as elongated legs with highly subdivided tarsi, the specimen exhibits a unique feature on the pedipalps in the form of an additional element, possibly representing a subdivided tarsus. Such a pedipalp morphology is so far unknown in both modern and fossil representatives of Opiliones. It highlights a rare morphological singularity in Opiliones and complements the sparse fossil record of harvestmen preserved in amber. The massive pedipalps resemble those of armoured harvestmen (Laniatores), yet the specimen is more likely a representative of Phalangiidae. The additional joint in the pedipalps of the newly described specimen possibly allowed it to catch small-sized prey.
A new collection of Upper Jurassic (Kimmeridgian) gastropods from the reefal limestones of the Saal quarry near Kelheim (Lower Bavaria, Germany) is reported. It has yielded 119 species of which 80 species are nominate species, the others are treated in open nomenclature. This increases the number of known gastropod species from the Saal quarry by 54 (31 nominate species). A total of 178 gastropod species (107 nominate species) have now been reported from this locality making this occurrence the richest one from the Late Jurassic. Despite the fact that previously studied collections are from the same quarry and have the same age, these collections differ considerably from each other in species composition and relative abundances of shared species. This reflects facies differentiation in the quarry as well as colletion biases. One new genus (Kelheimia gen. nov.) and 15 new species are described: Scurriopsis cragolis sp. nov., Pseudorhytidopilus ? quadratus sp. nov., Rimulopsis danuviensis sp. nov., Nododelphinula oblonga sp. nov., Creniturbo gibbosus sp. nov., Kelheimia triangulata sp. nov., Neritopsis ? rotundatus sp. nov., Oonia kimmeridgiensis sp. nov., Eustoma ? gracilis sp. nov., Cryptoptyxis ? spinosus sp. nov., Turritella lucagrita sp. nov., Neuburgensia angulata sp. nov., Neuburgensia rara sp. nov., Diarthema aspera sp. nov., and Aphanoptyxis sinerugae sp. nov. Leptomaria tuberosa Gründel, Keupp & Lang, 2017 is seen as subjective synonym of Leptomaria goldfussi (Sieberer, 1907). Gymnocerithium ? convexoconcavum Gründel, Keupp & Lang, 2019 is placed in the genus Neuburgensia (comb. nov.). Amphitrochus ? gerberi Gründel, Keupp & Lang, 2017 is placed in the genus Serrettella (comb. nov.). Neritopsis subvaricosa Brösamlen, 1909 is placed in the genus Hayamiella (comb. nov.). Gymnocerithium ? convexoconcavum Gründel, Keupp & Lang, 2019 is placed in the genus Neuburgensia (comb. nov.). Nerinea tricincta Münster, 1844 is placed in the genus Aptyxiella (comb. nov.). Nerinea staszycii (Zeuschner, 1850) is placed in the genus Endoplocus (comb. nov.). Polyptyxisella clio (d’Orbigny, 1852) is placed in the genus Ptygamtis (comb. nov.).
NIKOLAOS KARGOPOULOS, ALBERTO VALENCIANO, PANAGIOTIS KAMPOURIDIS
et al.
The present work deals with the carnivorans found in five Neogene localities in eastern Romania: the Vallesian locality of Păun, the Turolian localities of Pogana 1 and Creţeşti 1, and the Ruscinian localities of Bereşti and Măluşteni. The presented material includes cranial and postcranial specimens, some of which are herein described for the first time. This study includes a re-description and re-depiction of the type material of Lutra rumana Simionescu, 1922 and Promephitis malustenensis Simionescu, 1930, in order to clarify the taxonomic position of these two enigmatic taxa. The carnivoran faunal lists of all five localities are reviewed offering interesting insights into the temporospatial range of the discovered forms. Most localities have only yielded a limited number of species, except from Măluşteni, which shows evidence of at least nine different coexisting forms. Notable occurrences in terms of biostratigraphy include Paludolutra sp. in Pogana 1, Protictitherium crassum (Depéret, 1892) in Creţeşti 1, and a phocid from Măluşteni. This review aims to aid the understanding of the Neogene ecosystems in the north of the Paratethys in terms of faunal contents, biostratigraphy and palaeoecology.
Jozef Klembara, Marcello Ruta, Jason Anderson
et al.
Abstract The Upper Carboniferous protorothyridid amniote Brouffia orientalis from Czech Republic is redescribed. Photogrammetric scanning of the holotype and only known specimen yields considerable new information on the skull and postcranium of this tetrapod and allows us to amend previous morphological descriptions to a substantial degree. A virtual 3D model built from photogrammetry scan data is used as the basis for a new reconstruction of the skull in dorsal, lateral, and ventral aspects and the lower jaw in lateral aspect. We expand and refine the diagnosis of Brouffia and compare it with other protorothyridids. We discuss the affinities of this taxon by coding it in a recently published data matrix of early amniotes, which we subject to maximum parsimony and Bayesian fossilized birth–death analyses. Brouffia emerges as the sister taxon to Coelostegus in all analyses, but the position of these two taxa within amniotes varies. In a parsimony analysis with unweighted characters, the (Brouffia + Coelostegus) clade forms the sister group to Synapsida. In various experiments of character reweighting, that clade is placed crownward of Captorhinidae on the stem-group of Reptilia, but anticrownward of remaining protorothyridids. The latter constitute either a paraphyletic array relative to Diapsida or their monophyletic sister group. The Bayesian analysis retrieves (Brouffia + Coelostegus) as the most basal plesion on the stem-group of Reptilia.
Systematic palaeontological and biometric-statistical analyses (classical clustering and linear discriminant analysis)
of statistically significant populations of three early Turonian ammonite species from offshore marls of the Brießnitz
Formation (Saxonian Cretaceous Basin, eastern Germany) were used to evaluate a formerly just visually suspected hypothesis
of a size dimorphism within the taxa. The studied faunas can in fact be regarded as contemporaneous late early
Turonian fossil assemblages derived from a palaeobiogeographic and depositional entity. However, only one of the three
species passed the statistical tests. Neither in Lewesiceras peramplum nor in Mammites nodosoides can a dimorphism
be proven. In both taxa, no other features than size can be recognised that differ significantly between the overlapping
groups. Furthermore, adulthood cannot be proven due to the absence of unequivocal mature modifications. Thus, a
combination of large intraspecific variability and commonly incompletely preserved (i.e., small) specimens dissembles
dimorphic populations at a first glance. On the other hand, the suspected dimorphism in Spathites (Jeanrogericeras)
reveliereanus
was confirmed by the statistical analyses of numerous biometric parameters. Not only the maximum diameters
but also the distinct apertural cross-sections and ornament show significant differences between the statistically
clearly separated two groups. Furthermore, a decline in ornament and widening of the body chamber in fully grown
macroconch specimens, regarded as a mature modification of the shell, demonstrate that the antidimorphs really differed
in adult morphology. Thus, it can be shown that there are in fact two forms in the fossil assemblage of S. (J.) reveliereanus
that, based on their morphological differences and lack of any overlap, represent micro- and macroconchs (inferred
males and females) of an evidently dimorphic ammonite species. Finally, we conclude that simple visual inspection is
commonly insufficient for the reliable proof of dimorphism in ammonoids.
Abstract The coquina on the banks of the Oued Beth in the Rharb Basin in northwestern Morocco has long been known to be exceptionally rich in fossils. The stratigraphic position ranging from the Late Miocene to the Pliocene has been controversial, however. In the course of my master’s degree field work in 1975/76, I mapped the right bank of the Oued Beth from Dar bel Hamri to El Kansera. Following multiple recent studies in the general region, I here review my results and present an updated comprehensive stratigraphic and geologic frame for the first time. The coquina near Dar bel Hamri is interpreted to be of Early Pliocene age, possibly containing some reworking of Late Miocene fossils. The coquina and other locations along the Oued Beth have yielded a rich otolith assemblage, which is described in this article. It represents the first fossil otolith-based fish fauna described from Northwest Africa and contains 96 species, 16 of which are new. The new species in the order of their description are Diaphus maghrebensis n. sp., Ophidion tuseti n. sp., Centroberyx vonderhochti n. sp., Myripristis ouarredi n. sp., Deltentosteus planus n. sp., Caranx rharbensis n. sp., Trachurus insectus n. sp., Parapristipoma bethensis n. sp., Pomadasys zemmourensis n. sp., Cepola lombartei n. sp., Trachinus maroccanus n. sp., Trachinus wernlii n. sp., Uranoscopus hoedemakersi n. sp., Uranoscopus vanhinsberghi n. sp., Spondyliosoma tingitana n. sp., and Opsodentex mordax n. sp. In addition, a new species is described from the Tortonian and Zanclean of Italy: Rhynchoconger carnevalei n. sp. Some additional otoliths are described from another Northwest Moroccan location of Early Pliocene age near Asilah, 50 km south of the Strait of Gibraltar. The Early Pliocene fish fauna from Dar bel Hamri in the Rharb Basin is also of interest, because it constitutes the nearest Atlantic fauna of the time of the reconnection of the Mediterranean with the Atlantic and may have acted as a hosting area for the remigration of fishes into the Mediterranean. Indeed, the correlation is high between the Northwest Moroccan and the well-known time-equivalent Mediterranean fish fauna, but the Moroccan fauna also contains a good proportion of putative endemic taxa and taxa with tropical West African affinities that apparently did not migrate into the Mediterranean. Thus, the Early Pliocene fish fauna from the Rharb Basin represents a unique assemblage for which I propose the biogeographic term “Maghrebian bioprovince.” ZooBank LSID: urn:lsid:zoobank.org:pub:E01D698A-C1EE-4D32-B60D-4EF73AFFFCCF https://zoobank.org/65C520AE-72FB-4153-8D18-8695BB5A7E3F
Céline Weber, Michael Hautmann, Amane Tajika
et al.
Abstract The impact of increasing atmospheric CO2 and the resulting decreasing pH of seawater are in the focus of current environmental research. These factors cause problems for marine calcifiers such as reduced calcification rates and the dissolution of calcareous skeletons. While the impact on recent organisms is well established, little is known about long-term evolutionary consequences. Here, we assessed whether ammonoids reacted to environmental change by changing septal thickness. We measured the septal thickness of ammonoid phragmocones through ontogeny in order to test the hypothesis that atmospheric pCO2, seawater pH and other factors affected aragonite biomineralisation in ammonoids. Particularly, we studied septal thickness of ammonoids before and after the ocean acidification event in the latest Triassic until the Early Cretaceous. Early Jurassic ammonoid lineages had thinner septa relative to diameter than their Late Triassic relatives, which we tentatively interpret as consequence of a positive selection for reduced shell material as an evolutionary response to this ocean acidification event. This response was preserved within several lineages among the Early Jurassic descendants of these ammonoids. By contrast, we did not find a significant correlation between septal thickness and long-term atmospheric pCO2 or seawater pH, but we discovered a correlation with palaeolatitude.
Tooth replacement rate is an important feature related to feeding mechanics and food choices for dinosaurs. However, only a few data points are available for sauropod dinosaurs, partially due to rarity of relevant fossil material. Four somphospondylan sauropod species have been recovered from the Lower Cretaceous Aptian–Albian Haoling Formation in the Ruyang Basin, Henan Province of central China, but no cranial material has been reported except for a single crown. Here we report the discovery of the rostral portion of a left dentary with replacement teeth in its first five alveoli. Comparative anatomical study shows the partial dentary can be assigned to a member of early diverging somphospondylans. The non-destructive tooth length-based approach to estimating tooth formation time and replacement rate is adopted here. The estimated tooth replacement rate is 76 days, faster than that of Brachiosaurus (83 days) and much lower than typical late diverging lithostrotian titanosaurians (20 days). Thus, this discovery adds an intermediate tooth replacement rate in the evolution of titanosauriform sauropods and supports the idea that evolution of tooth replacement rate is clade-specific. This discovery also provides more information to understand the Ruyang sauropod assemblage, which includes one of the most giant dinosaurs to have walked our Earth (Ruyangosaurus giganteus).
<p>The ichthyosaur fossil record of Portugal is composed of
specimens from the localities of São Pedro de Moel, Alhadas, Cadima, Murtede,
Casal do Combo, Condeixa, Alvaiázere and Tomar, within the confines of
the Lusitanian Basin, ranging in age from the Sinemurian to the Aalenian. We
reviewed the historical ichthyosaur finds in Portugal, and in this work we
focus on the specimen IST-MDT 85, from the Sinemurian of Praia de Nossa
Senhora da Vitória, central west coast of Portugal. The specimen was
herein ascribed to <i>Ichthyosaurus</i> cf. <i>communis</i>, based on characters of the humerus in comparison with
other specimens. This is the southernmost documented occurrence of
<i>Ichthyosaurus</i>, widening the geographical range of the genus.</p>
The Triassic reptile Eifelosaurus triadicus is an icon of the Geopark Vulkaneifel and the Natural History Museum of Gerolstein (West Eifel, Rhineland Palatinate, W Germany). We explore the research history, including geoconservation aspects, and summarize current knowledge of Eifelosaurus, the sole fossil of its kind, identified as an early rhynchosaur. We discuss the local geology, stratigraphy and paleontology of the Lower Triassic in the Eifel area, with emphasis on local palaeoenvironmental conditions during deposition of the Buntsandstein. Among those are spectacular finds of numerous lycopods at Lammersdorf, only few kilometers from Oberbettingen, the source of the partial skeleton of Eifelosaurus. The famous fossil is important for local geotourism, with a hiking trail leading to the quarry where the reptile was probably discovered. Eifelosaurus is an important geoeducational topic for school groups, tourists and locals who visit exhibitions in the “Naturkundemuseum” of Gerolstein, participate in programs and guided tours through the museum.
General. Including nature conservation, geographical distribution
Robert A. Gastaldo, Sandra L. Kamo, Johann Neveling
et al.
The end-Permian is associated with major changes in both marine and terrestrial biodiversity. Here, Gastaldo et al. present high resolution dating of the Lystrosaurus Assemblage Zone in the Karoo Basin, South Africa, demonstrating that the marine crisis did not mirror a coeval event on land.
Abstract Plesiosaurs are one of the common groups of aquatic reptiles in the Mesozoic, which mainly lived in marine environments. Freshwater plesiosaurs are rare in the world, especially from the Jurassic. The present paper reports the first freshwater plesiosaur, represented by four isolated teeth from the Middle Jurassic fluviolacustrine strata of Qingtujing area, Jinchang City, Gansu Province, Northwest China. These teeth are considered to come from one individual. The comparative analysis of the corresponding relationship between the body and tooth sizes of the known freshwater plesiosaur shows that Jinchang teeth represent a small-sized plesiosaurian. Based on the adaptive radiation of plesiosaurs and the palaeobiogeographical context, we propose a scenario of a river leading to the Meso-Tethys in the Late Middle Jurassic in Jinchang area, which may have provided a channel for the seasonal migration of plesiosaurs.
The Paleocene–Eocene thermal maximum (PETM) is
represented in numerous shallow and deep marine sections of the
south–central and western Pyrenees by a 2–4 m thick unit (locally up to
20 m) of clays or marly clays intercalated within a carbonate-dominated
succession. This unit records a massive input into the Pyrenean Gulf of
fine-grained terrestrial siliciclastics, attributed to an abrupt
hydrological change during the PETM. However, the nature of such a change
remains controversial. Here we show that, in addition to fine-grained
deposits, large volumes of coarse-grained siliciclastics were brought into
the basin and were mostly accumulated in incised valleys and in a long-lived
deep-sea channel. The occurrence of these coarse-grained deposits has been
known for some time, but their correlation with the PETM is reported here
for the first time. The bulk of the incised valley deposits in the PETM
interval are cross-bedded sands and pebbly sands, almost exclusively made of
quartz. The criteria for indicting a relation to the PETM include their
stratigraphic position between upper Thanetian and lower Ilerdian marine
carbonates, organic carbon isotope data, and a high percentage of kaolinite
in the clay matrix. The axially flowing deep-sea channel existed throughout
Paleocene times in the Pyrenean Basin, within which coarse-grained
calciclastic and siliciclastic turbidites were accumulated. This Paleocene
succession is capped by thickly bedded quartz sandstones and pebbly
sandstones, probably deposited by hyperpycnal flows, which are here assigned
to the PETM based on their stratigraphic position and organic carbon
isotopic data. The large and simultaneous increase in coarse- and
fine-grained terrestrial siliciclastics delivered to the Pyrenean Gulf
during the PETM is attributed to an increased intra-annual humidity
gradient. During the PETM a longer and drier summer season facilitated the
erosion of landscapes, whereas a dramatic enhancement of precipitation
extremes during the wet season led to intensified flood events, with rivers
carrying greater volumes of both bed and suspended loads. This scenario
argues against the possibility that PETM kaolinites indicate a coeval warm
and humid climate in northern Spain. Instead, the kaolinite reflects the
erosion of thick Cretaceous lateritic profiles developed on the Hercynian
basement.
Aaron R. H. LeBlanc, Amanpreet K Brar, William J May
et al.
Captorhinids were Paleozoic eureptiles that originated in the Late Pennsylvanian in Laurasia and dispersed across the major landmasses of Pangaea by the Late Permian. Their evolutionary success as omnivorous and herbivorous members of Permian terrestrial communities has been attributed to the evolution of multiple marginal tooth rows. Multiple tooth rows evolved at least twice within Captorhinidae: once in the omnivorous Captorhinus aguti and again in the diverse subfamily of herbivorous moradisaurines. The earliest known moradisaurines co-occured with C. aguti in Lower Permian strata of Texas; however C. aguti is also known from much older fissure fills in the famous Dolese Brothers quarry near Richards Spur, Oklahoma, suggesting that C. aguti preceded any other multiple-rowed captorhinid. Here we report on new material of multiple-rowed captorhinids from the Lower Permian fissure fills of the Bally Mountain locality in Oklahoma, only 35 miles from Richards Spur. Some of this material is referrable to Captorhinikos valensis, which was previously only known from younger strata in Texas, making this species the geologically and phylogenetically oldest moradisaurine. Furthermore, we determined that Ca. valensis co-existed with C. aguti at Bally Mountain and we explore the potential for niche partitioning in these early captorhinids. Lastly, we assess the potential temporal and environmental differences between Bally Mountain and Richards Spur, in order to explain the abundance of herbivorous moradisaurines at Bally Mountain and the complete lack of moradisaurines at the neighbouring Richards Spur locality.
The Late Campanian white Chalk of Meudon, a city located in the suburbs of Paris (France), has yielded during the 19th century several mosasaurid remains consisting mainly in isolated teeth, most being nowadays lost. These specimens, which history is associated to the most famous French palaeontologists of that time like Georges Cuvier, Paul Gervais and Albert Gaudry, represent the earliest mosasaurid discoveries from France. As such, they are precious and unique witnesses of a lost world. In this paper, an historical approach has been privileged, focusing on the history of their discovery and how they were originally perceived and interpreted by Cuvier and others. On a systematical point of view, the material is referred mostly to indeterminate species of the tylosaurine genus Hainosaurus but also of the plio- platecarpine Plioplatecarpus and possibly of the mosasaurine Prognathodon, attesting of the occurrence of the three major clades of mosasaurids in this Late Campanian marine vertebrate fauna of France.