Gaëtan J.-M. Potin, Pénélope Claisse, Alexis Trébaol
et al.
The Fezouata Shale Formation is an Early Ordovician Lagerstätte that preserved exceptionally detailed records of complex marine ecosystems, making it crucial for understanding the early evolution of animal life. It has yielded the youngest known community of radiodonts to date. This group is particularly well known from the Cambrian, with iconic representatives such as Anomalocaris, which are emblematic of the Cambrian explosion. Here we describe a new radiodont from the Fezouata Biota, Falciscaris mumakiana gen. et sp. nov. based on seven specimens of isolated frontal appendages. These appendages bear long endites with large and robust auxiliary spines, suggesting they were adapted for foraging through sediment in search of prey. The appendages of F. mumakiana gen. et sp. nov. can be relatively large compared to the majority of radiodont appendages, with endites reaching up to 11.4 cm in length, suggesting a total body size exceeding one meter for this Ordovician radiodont. In contrast, smaller specimens can be up to 10 times smaller, indicating ontogenetic stages during which the frontal appendage morphology changes little. Following the “Ordovician Plankton Revolution”, the proliferation of planktonic resources and enhanced pelagic-benthic coupling during this period likely allowed for the rise of giant suspension-feeding radiodonts, such as the Aegirocassisinae and F. mumakiana gen. et sp. nov., the new giant benthivore. In term of taxonomic diversity, benthivores radiodonts remain a minor component of radiodont diversity in the Fezouata Biota compared to the more dominant suspension feeders.
Bruce J. MacFadden, Cristobal A. Barberis, Maria C. Vallejo-Pareja
et al.
Abstract With the growing application of artificial intelligence (AI) and machine learning (ML), great potential exists to leverage these technologies in paleontology. Relative to many other scientific fields, a challenge of ML applied to paleontology is small sample sizes, particularly for fossil vertebrates. Shark teeth, abundant in the fossil record, provide a model system to use ML across varying sample sizes. Here we use six classes (taxa) of Neogene shark teeth for taxonomic identification, including a curated dataset of 3150 images. Each class was evaluated using an 80% training and 20% validation split, with a separate, external test set of 25 samples per class. Pretrained models perform well (accuracy > 90%), providing a strong baseline for classification. However, enabling fine-tuning of the ML model to identify fossil shark teeth improves performance considerably. Likewise, sample size per class also affects the accuracy of the models’ classifications. Smaller sample sizes ( n = 50 individuals per class) yielded a mean accuracy of 93.4%, but plateaued at ~99% between 200 and 500 images per class. Confidence likewise increases with larger samples, from 81.8% ( n = 50 individuals per class) to >90% ( n = 300 to 500 individuals per class). Misidentifications followed consistent patterns, reflecting morphological similarities and/or poor preservation. Artificially increasing the training datasets using data augmentation improves the confidence of identifications. This research indicates that relatively small samples of vertebrate species (~50 to 500 individuals per class) can effectively train an ML model to identify these shark teeth with high levels of accuracy.
AbstractFossil-Lagerstätten, or Lagerstätten, have played a critical role in our understanding of the diversity, abundance, evolution, and systematics of marine arthropods. The tendency toward preservation of Phanerozoic marine arthropods as fossils generally increases as a factor of biomineralization. Concentration deposits (Konzentrat-Lagerstätten) tend to have an abundance of biomineralized arthropod taxa, whereas conservation deposits (Konservat-Lagerstätten) tend to produce a higher biodiversity that includes biomineralizing and non-biomineralizing taxa. Some Lagerstätten incorporate aspects of both concentration and conservation deposits, indicating that these concepts are idealizations, or preservational end members. For arthropod occurrences, it is useful to consider another dimension of Lagerstätten: their taphonomic associations. This leads to a more nuanced understanding of arthropod fossilization history. Four taphonomic associations account for a substantial number of marine arthropod occurrences: (1) concretions, (2) clusters, (3) event beds, and (4) microbially sealed sediments. Each of these occurrences can blur the distinctions between, or the means of recognizing, the idealized genetic categories of concentration deposits and conservation deposits.
Abstract The Quercy Phosphorites area (Southwestern France) provides more than 200 fossiliferous localities, ranging from the early Eocene to the Early Miocene. These localities document a rich and diverse continental fauna and highlight a massive turnover in vertebrates around the Eocene–Oligocene transition. Among them, the locality of La Bouffie, from the early late Eocene (MP 17A) has yielded a diverse herpetofauna, including rare taxa for Europe (e.g., Tupinambinae). Unfortunately, most of the herpetofauna has never been described nor illustrated, leaving uncertainties regarding its true diversity. We here describe “forgotten” and undescribed specimens from La Bouffie, that pertain to pyxicephalid anurans, and gekkotan, lacertid, amphisbaenian, pleurodontan, glyptosaurid, anguine, helodermatid and palaeovaranid lizards. Among them, five taxa are identified for the first time in La Bouffie, including two new genera and species: Phosphoriguana peritechne gen. et sp. nov. (?Pleurodonta) and Cadurcopanoplos vaylatsensis gen. et sp. nov. (Glyptosauridae). Phosphoriguana peritechne gen. et sp. nov. represents the fourth pleurodontan genus from the late Eocene of Europe, highlighting the diversity of the clade on the continent prior to the “Grande Coupure”. The glyptosaurine glyptosaurid Cadurcopanoplos vaylatsensis gen. et sp. nov. represents only the second late Eocene glyptosaurine from Europe, differing from Placosaurus in having a cranial osteoderm pattern reminiscent of early Eocene glyptosaurines, like Sullivanosaurus; it therefore suggests a higher diversity of this group in the late Eocene. A review of the herpetofauna of La Bouffie identifies at least 18 illustrated and formally described taxa, while other 8 need to be properly reassessed, as the latter have only been so far briefly mentioned. This renders La Bouffie one of the most diverse late Eocene localities in Europe.
In this study, we analyze the formation process of the collection that Florentino Ameghino presented to the occidental world at the Universal Exposition, which took place in Paris in 1878 and from which he materially supported his theory regarding the antiquity of “men” in the Río de La Plata Basin. We develop an analysis based on the same structure of the “Catalogue spécial de la section Anhtropologique et Paléontologique de la République Argentine a L’expositionuniverselle de Paris (1878)” and we contrast it with the information provided in his previous works. In this Special Catalog, Ameghino provided information on human, faunal, and cultural remains, which contributed to the construction of his collection up until before the exhibition. The structuring of the Special Catalog connects us with the evolution of Ameghino’s scientific thought through his classification regarding the natural or anthropic origin of the objects, the temporal order that he assigned to the findings, and the sedimentary deposits carrying the objects. We analyze the classificatory categories, their implications, and the curatorial destinations of the collection that Ameghino presented in Paris. The analysis of this collection, which nowadays constitutes one of the most important regarding the knowledge of the antiquity of the human population in South America and its relationship with the fossil mammals of the Pleistocene–Holocene, is limited by the dissociation of the cultural and biological evidence that was found in the same context and that is currently housed in different national and foreign institutions.
Abstract The osteology and the systematic position of Caturus enkopicaudalis sp. nov. a fossil fish from the marine Upper Jurassic of Southern Germany, are studied in details. The characters of the skull, the general morphology and some features of the caudal skeleton strongly support the referral of this fish to the family Caturidae within the order Amiiformes. The new species belongs to the genus Caturus having a slender rod like maxilla; a high number of branchiostegal rays; block-like ural neural arches. Caturus enkopicaudalis differs from the other species of the genus mainly in the shape of the caudal fin, which is double emarginate with a central plateau; multiple small ganoin scales covering the anterior part of the caudal fin and the significantly higher number of scales rows.
The pineal eye is a photoreceptive organ, sometimes called the “third eye”, housed within the parietal foramen of some ectothermic vertebrates (Eakin 1973; Quay 1979). It is amongst the most enigmatic organs, and accordingly, concerns relating to its origin and evolution have long fascinated palaeontologists (Eakin 1973; Roth and Roth 1980; Benoit et al. 2016). In dicynodont synapsids, a parietal foramen is almost always present, with a few noticeable exceptions that have, so far, eluded explanations (Benoit et al. 2016; Kammerer 2019). Kombuisia frerensis is one such exception. There are two recognised species of Kombuisia: K. frerensis, from South Africa, and K. antarctica, from Antarctica. The two species are virtually undistinguishable except for the absence of a parietal foramen in the former, whereas the latter retains a slit-like opening on the skull roof (Fröbisch et al. 2010). While describing K. frerensis, Hotton (1974) refrained from including the absence of a parietal foramen in the diagnosis of the species as very little was known about the intraspecific variability of this character. Intraspecific variation of the parietal foramen has since been documented in modern reptiles (e.g., Gundy and Wurst 1976; Roth and Roth 1980) and other synapsids (Benoit et al. 2016). As a result, the absence of a parietal foramen in K. frerensis has been treated with caution by subsequent authors (e.g., Kammerer 2019). In 2023, our research team found a new specimen referrable to K. frerensis: an almost undeformed skull with articulated lower jaw and associated postcrania (Fig. 1A). This new specimen confirms that the absence of a parietal foramen is diagnostic for K. frerensis. We here explore the physiological implications of this condition and propose that it may be the result of latitudinal gradient separating the two species of Kombuisia.
The “Stanford ranking” (SR) of standardized citation indicators calculates an individual scientist’s composite c-score, addressing limitations of the h-index. Updated annually, the SR lists the top 100,000 scientists and the top 2% in each specialty. This study examines all (500) palaeontologists included in the SR (SR-palaeontologists), comparing their h-index, c-score and related productivity and citation variables. Analyses cover geographical distribution, statistical characterization and relationships among variables. SR-palaeontologists are concentrated mainly in North America and central-northern Europe. An average SR-palaeontologist has a 41-year career and 165 publications: 51 as first or single author (author), 69 as intermediate author (collaborator) and 45 as last author (manager). This imaginary scientist has received about 9,400 citations (17% self-citations): 2734 as author, 4720 as collaborator, and 1948 as manager. The average h-index is 47, and the mean c-score is 3.65. These metrics show weak correlation and little dependence on career length. Rankings differ markedly depending on whether the h-index or c-score is applied. Palaeontologists with high h-indices (h-palaeontologists) typically have more papers and citations, especially as collaborators or managers, and higher self-citation rates. In contrast, those with high c-scores (c-palaeontologists) generally produce fewer papers and citations overall, show lower self-citation rates and obtain a larger share of citations from work as authors rather than collaborators or managers. Expanding the database to include the broader palaeontological community would enable a more comprehensive assessment of citation performance and better inform evaluation practices. To the author’s knowledge, this is the first global, discipline-wide analysis conducted using the SR.
Toda obra de paleoarte representa seres, objetos de estudios paleobiológicos, enmarcados en un espacio y un tiempo, que son observados por nosotros, que también estamos acotados espaciotemporalmente. Se valoran las razones de la importancia histórica del paleoarte, estimando que su arraigo es resultado de la triple interacción entre la esfera científica, artística y social. Al explorar el papel que juegan los contextos sociales y la cultura popular en el paleoarte, se consideran cinco etapas: (1) las ilustraciones científicas, (2) las narrativas vinculadas al inicio de la paleontología como disciplina, (3) la irrupción de los museos didácticos, (4) el paleoarte y la independencia de los paleoartistas y (5) la implicancia popular y de las redes sociales. Los paradigmas que subyacen en estas etapas ponen de relieve cómo las emociones, la enseñanza, la pedagogía y las exigencias de la cultura popular están presentes, en mayor o menor medida, en las estéticas paleoartísticas. Finalmente, para entender lo que comunica el paleoarte, se utilizan los ejes de la espacialidad para captar los distintos niveles de información que transmiten sus producciones.
This study describes an assemblage of Dzieduszyckia brachiopods preserved in sedimentary barite deposits from
the Famennian, Upper Devonian of Nevada, USA. The brachiopods lived in a methane-seep environment like those
described from Sonora, Mexico, and the Western Meseta, Morocco. Although the original carbonate fabrics are not
preserved, pockets of limestone within the brachiopod barite are depleted in with δ13C values ranging from -31.1 to
-27.3‰ VPDB. The fossils are preserved as internal and external molds only but record enough detail to demonstrate
key internal features of Dzieduszyckia such as a pronounced dorsal septum, septalium, and vertical dental plates. The
lack of common bifurcation or trifurcation of the costae as well as larger size of the shells recommends against inclusion
within D. sonora as previously published. Based on the number of costae per width of shell, it is possible that there are
two distinct species in Nevada, like other localities in Morocco, the Urals, and South China. These new data expand the
body of knowledge of these earliest dimerelloids and it is hypothesized that this seep-dwelling macrofauna arose from
depauperate-successful lineages between the Famennian biotic crises. As nearly all global Dzieduszyckia deposits are
associated with active tectonic margins, it is also suggested that tectonically-driven methane expulsion in low nutrient
waters spurred the evolution of dimerelloids.
Abstract Bernhard Peyer (1885–1963) was a prominent Swiss vertebrate palaeontologist and anatomist at the University of Zurich. In 1919, he discovered the occurrence of Middle Triassic (Anisian–Ladinian) ichthyosaurs, sauropterygians, and other reptiles at Monte San Giorgio on the border between Switzerland and Italy. Starting in 1924, Peyer, and later his student and successor Emil Kuhn-Schnyder, worked tirelessly to excavate and collect material from fossil-bearing deposits in this region. The discovery of an articulated skeleton of a long-necked reptile in 1929 allowed Peyer to solve the riddle of unusually elongate bones from the German Muschelkalk, which, he demonstrated, were cervical vertebrae of the extraordinarily long-necked reptile Tanystropheus. As a student in 1919 and later in 1942, Peyer explored a Rhaetian bonebed close to his native town of Schaffhausen. Processing the sediment, he recovered numerous small bones and teeth of vertebrates, among which teeth of diverse stem-mammals are of particular importance.
THOMAS SAUCÈDE, CHRISTOPHER SMITH, NICOLAS OLIVIER
et al.
Knowledge of the early evolution of post-Palaeozoic crinoids mainly relies on the well-preserved and abundant material
sampled in Triassic Konservat-Lagerstätten such as those from the Anisian Muschelkalk (Middle Triassic) of the
Germanic Basin. These crinoid-bearing Lagerstätten have been central to understanding the rapid evolution and diversification
of crinoids after the dramatic Permian/Triassic Boundary biological crisis that led the class to near-extinction.
The Encrinida are the emblematic crinoids of the Triassic. They are mainly known from rich fossil deposits where their
abundant ossicles are at the origin of the extensive crinoidal limestone beds of the German Upper Muschelkalk. So far,
they were first represented in the Middle Triassic by the family Dadocrinidae and genus Dadocrinus. In the present work,
a new species Dadocrinus montellonis sp. nov., is described based on a well-preserved, almost complete articulated specimen
from the Spathian (Lower Triassic) of Nevada (USA). The new species differs from other species of Dadocrinus by
its palaeobiogeographic position but also by its earlier stratigraphic occurrence and ancestral morphology. It represents
the first reported occurrence of Dadocrinus outside the Germanic Basin prior to the Middle Triassic and also the oldest
firm evidence of its presence in the Early Triassic (middle–late Spathian). This discovery sheds new light on the origin
of post-Palaeozoic crinoids. It suggests a much wider distribution than commonly assumed for the genus Dadocrinus
and implies that the first dadocrinids originated either in the Panthalassa or Tethys oceans, and then dispersed over long
distances in a relative short period of time.
Gabriel A. Casal, Lucio M. Ibiricu, Bruno N. Alvarez
et al.
Se analizan los factores intrínsecos y extrínsecos que controlaron la preservación del saurópodo rebaquisáurido Katepensaurus goicoecheai, procedente de la Formación Bajo Barreal (Grupo Chubut-Cretácico Superior) en el centro-sur de Chubut, cuenca del Golfo San Jorge, Patagonia central, Argentina. Los restos se preservaron en un depósito de desbordamiento no canalizado, de geometría lobulada, de 30 cm de potencia y vinculado a canales fluviales arenosos. Litológicamente está integrado por areniscas gruesas con abundante matriz pelítica y tobácea,
que permiten caracterizarlo como un flujo hiperconcentrado. Los elementos recuperados, que corresponden principalmente al esqueleto axial, yacían sobre depósitos pelíticos de una planicie de inundación distal mal drenada y fueron parcialmente cubiertos por el lóbulo de desbordamiento, quedando estructuras expuestas que fueron intensamente erosionadas. Los restos se encontraron incompletos, desarticulados y exhibiendo evidencias de una exposición subaérea prolongada. Fueron poco movilizados por procesos hidráulicos y reorientados de forma normal a la dirección del desbordamiento. La dispersión lateral muestra grupos de huesos producto de entrampamientos hidráulicos causados por los restos de mayor tamaño en la parte central del lóbulo y los más pequeños hacia los laterales acorde a la distribución de energía del depósito. La escasa potencia del desbordamiento no sepultó completamente los restos. Finalmente, un nuevo desbordamiento cubrió completamente los materiales. La acumulación de huesos de Katepensaurus sería una concentración ósea residual y representa una acumulación parautóctona de origen sedimentológico.
New discoveries of Cenozoic deep-water hydrocarbon seep deposits and continued collecting at previously documented
sites in the North Pacific region have resulted in additional fossils of vesicomyid bivalves and necessitate a systematic review.
We report five new vesicomyid species, including four species from western Washington State, USA: Isorropodon
humptulipsense sp. nov. from middle to upper Eocene strata of the Humptulips Formation and the “Siltstone of unit B”,
the oldest record for Isorropodon, Pleurophopsis thieli sp. nov. from upper Eocene to lowermost Oligocene strata of the
Lincoln Creek, Makah, and Pysht formations, and Pliocardia? guthrieorum sp. nov. and Squiresica plana sp. nov. from
Oligocene strata of the Lincoln Creek and Pysht formations. The new species Squiresica yooni sp. nov. is from the Middle
Miocene Duho Formation in South Korea. We report possibly the as-yet oldest Vesicomya from a lower Oligocene seep
deposit in the Lincoln Creek Formation in western Washington. Pliocardia kawadai was previously only known from
Lower to Middle Miocene strata in Japan; with our new record from the Lower to Middle Miocene Astoria Formation
in western Washington, this species represents the first fossil vesicomyid species with a trans-Pacific distribution. The
large and elongated Pleurophopsis chinookensis is restricted to upper Eocene strata; previous Oligocene records are
shown to belong to other species.
Although the Neogene deposits of the Calchaquíes Valleys, northwestern Argentina, have been intensively studied, there are only a few works dealing with the calcareous microfauna. Thus, this study aims to provide detailed systematic descriptions of the calcareous microfauna recorded at the Playa del Zorro Alloformation and Chiquimil Formation, units exposed at the El Cajón Valley and Pampa hill respectively, Catamarca Province. Also, an assessment of the paleoenvironment, based on the calcareous microfossil association was carried out for both units. As a result, a new species of the ostracod genus Cyprideis Jones was recognized, namely Cyprideis calchaquiensis nov. sp., which was found associated with Perissocytheridea carrenoae Nicolaidis & Coimbra, Limnocythere spp. and the foraminifera Ammonia tepida Cushman. The low diversity assemblage, the predominance of rounded sieve pores on the valve surface of C. calchaquiensis nov. sp., and the presence of abnormal tests of A. tepida point to a shallow stressed water body that suffered evaporation episodes, resulting in fluctuating salinity. Interestingly, close similarities were observed between the Playa del Zorro Alloformation and Chiquimil Formation with the upper section of the Yecua Formation, Bolivia. This affinity could be explained by the passive dispersal capacities of the ostracods and foraminifers, the ecological preferences of the recognized taxa and the proximity of the outcrops, assisted by the development of mega wetlands.
Abstract For the first time, nautilids from the Besano Formation (Anisian/Ladinian boundary) are documented. The extremely rare material was collected from two different outcrops at Monte San Giorgio (Southern Alps, Ticino, Switzerland). This material is represented by only five specimens described here. The three best specimens belong to the taxa Enoploceras rieberi sp. nov., Germanonautilus aff. ellipticus and Syringonautilus sp. indet., documenting the presence of the families Tainoceratidae and Syringonautilidae in the middle Besano Formation. Another nautilid specimen is described in open nomenclature, representing an additional taxon. The new species Enoploceras rieberi n. sp. is currently the only occurrence of the genus Enoploceras in the Middle Triassic. Nautilida are poorly known from the Middle Triassic Tethyan region, mostly from sediments deposited in pelagic environments. This is the first record of these nautilids from an usually anoxic depositional paleoenvironment of an intra-platform basin, where the sediments of the Besano Formation were laid down. ZooBank LSID: urn:lsid:zoobank.org:pub:61CF9E69-0F12-4D63-8CD7-0F2C8BA15C7C
Yanjie Zhang , Chungkun Shih, Alexandr P. Rasnitsyn
et al.
Fleas are highly specialized holometabolic insects. So far, only 16 species of fossil fleas in five families have been reported due to the rare fossil records. At present, the earliest flea fossils are reported from the Middle Jurassic Jiulongshan Formation of Northeastern China. The descriptions of these earliest species pushed back the origin of Siphonaptera by at least 40 million years. It is generally accepted that saurophthirids are the “transitional” taxa from stem Jurassic fleas to living crown groups. Herein, we described a new “transitional” flea species, Saurophthirus laevigatus Zhang, Shih, Rasnitsyn, and Gao sp. nov., from the Lower Cretaceous Yixian Formation of Northeastern China, assigned to Saurophthiridae. The new species provides new evidence to support saurophthirids as a “transitional” group. Sexual dimorphism suggests significant differences in biology of opposite sexes in Saurophthirus. Analysis of described Mesozoic species demonstrates the body size reduction from the Middle Jurassic to the Early Cretaceous. Smaller body size was likely advantageous in reducing the probability of being detected and removed by the host and in minimizing flea’s demand for blood intake and energy input, indicating the adaptation of the ectoparasitic lifestyle of fleas in their early stage of evolution.