Arnaud Begat, Eduardo Villalobos-Segura, Patrick L. Jambura
et al.
The extinct elasmobranch Protospinax is an intriguing shark known mostly from isolated teeth and rare complete skeletons. Most previous studies focused on differences in isolated teeth for taxonomic assignments, with little to no considerations of dental variations. In this study we provide a detailed morphological evaluation of the dentition of the squalomorph shark, Protospinax based on three skeletal remains of Protospinax annectans from the famous Upper Jurassic lithographic limestone of the Solnhofen area (Bavaria, Germany) with partially preserved dentitions and isolated teeth from the Kimmeridgian of Mahlstetten (Baden-Württemberg, Germany). The aim of this study is to clarify ambiguities in dental morphologies and to establish heterodonty patterns, allowing to taxonomically reassess species previously assigned to Protospinax. Accordingly, we consider Protospinax annectans (Callovian–Aptian?), Protospinax carvalhoi (Bathonian), Protospinax lochensteinensis (Oxfordian), and Protospinax planus (Kimmeridgian) as valid species. The species of Protospinax bilobatus is considered a junior synonym of Protospinax magnus. Furthermore, our results show that the dental morphologies of P. magnus and Protospinax? muftius are very different from those of other Protospinax species and rather resemble those of orectolobiforms. Consequently, we introduce two new orectolobiform genera, Jurascyllium gen. nov. and Archaeoscyllium gen. nov., to accommodate these species. The review of the species confirms a stratigraphic range of Protospinax extending from the Toarcian (Lower Jurassic) to the Valanginian (Lower Cretaceous).
Mohammed Yaqoob, Mohammed Ishaq, Mohammed Yusuf Ansari
et al.
Abstract Understanding ancient organisms and their interactions with paleoenvironments through the study of body fossils is a central tenet of paleontology. Advances in digital image capture now allow for efficient and accurate documentation, curation, and interrogation of fossil forms and structures in two and three dimensions, extending from microfossils to larger specimens. Despite these developments, key fossil image processing and analysis tasks, such as segmentation and classification, still require significant user intervention, which can be labor-intensive and subject to human bias. Recent advances in deep learning offer the potential to automate fossil image analysis, improving throughput and limiting operator bias. Despite the emergence of deep learning within paleontology in the last decade, challenges such as the scarcity of diverse, high quality image datasets and the complexity of fossil morphology necessitate further advancement which will be aided by the adoption of concepts from other scientific domains. Here, we comprehensively review state-of-the-art deep learning based methodologies applied to fossil analysis, grouping the studies based on the fossil type and nature of the task. Furthermore, we analyze existing literature to tabulate dataset information, neural network architecture type, and key results, and provide textual summaries. Finally, we discuss novel techniques for fossil data augmentation and fossil image enhancements, which can be combined with advanced neural network architectures, such as diffusion models, generative hybrid networks, transformers, and graph neural networks, to improve body fossil image analysis.
Gonzalo A. Collado, Fernando F. Galleguillos, Bert W. Hoeksema
According to the International Code of Zoological Nomenclature (ICZN, 1999), the Principle of Homonymy (Article 52) states that when two or more taxa are distinguished from each other, they must not be denoted by the same name because this would cause confusion. Consequently, in a case of homonymy, only the senior name may be used as valid (Art. 52.2). The ICZN (1999) also indicates that if the rejected junior homonym has no known available and potentially valid synonym, it must be replaced by a new substitute name (Art. 60.3), that is, a replacement name.
Abstract The Lower Jurassic cephalopod fauna recorded from an olistolith in the vicinity of Lukoveček (Czech Republic, Moravia) has been studied in detail. Seven ammonite taxa belonging to four genera and eight belemnite taxa of five genera are herein described and discussed within the stratigraphical and palaeobiogeographical context. Ammonites indicate the Upper Pliensbachian Margaritatus and Spinatum ammonite zones, which is consistent with the stratigraphic ranges of the associated belemnites. The analysis of the cephalopod assemblage recorded in the olistolith shows a relatively low diversity in the Upper Pliensbachian of Western Tethys. Our study suggests possible faunal exchanges between the Central and the Outer Carpathian units, between the European shelf and Western Tethys. This research contributes significant insights into the palaeogeographical development and sedimentary history of the Western Carpathians during the Lower Jurassic period, highlighting the importance of the Lukoveček olistolith as a unique information source of otherwise disappeared palaeogeographical areas.
Dámaso Antonio Larrañaga was born in 1771 in Montevideo, a city that, by those years, integrated the territories of the Virreinato del Perú, and died in 1848 in the same city, current capital city of República Oriental del Uruguay. Until his death, the natural sciences played a fundamental role in his daily activities and were marked by his religious vocation and his participation in the complex struggle for the independence of South America and Uruguay. As a man of science, he studied botanical, geological, paleontological, zoological, linguistic, and ethnolinguistic topics, under different perspectives related to taxonomy, classification, anatomy, stratigraphy, herbalism, and native lexicography, among others. Parts of his work, manuscripts and drawings, were extensively published during the second decade of the 20th century. A small note of his authorship was included in the second edition of the work entitled Recherches sur les ossemens fossiles de quadrupeds by Georges Cuvier, published in 1823. Its content had a strong impact on the international scientific community because he included Megatherium as a subgenus of the armadillo Dasypus, postulating that this large mammal had an external armor. In this contribution, we analyze the work of Larrañaga and recreate the scientific context in which Megatherium was inscribed as an armored mammal. As a result, we intend to associate this inference in the diverse postulates concerning the classification of mammals, which, at that time, were based on dental structures, as well as the influence exerted by the interaction between prominent naturalists of the 19th century.
Kévin Le Verger, Charlène Letenneur, Valentin Fischer
et al.
Abstract The amphicyonids, colloquially called ‘beardogs’, are one of the oldest known groups of caniformians, taking part in the initial radiation of this carnivoran clade. While the oldest American occurrences from the Middle Eocene have been investigated in detail, the European material remains understudied. The oldest European occurrences suggest an appearance of caniformians in the Priabonian of southern France and a diversification during the Oligocene, after a major faunal turnover following drastic climatic and environmental changes, the ‘Grande Coupure’. Their first representative is the amphicyonid Cynodictis lacustris, the cranial osteology of which is of much relevance for the systematics of Caniformia. A well-preserved cranium of Cynodictis lacustris was collected in the Phosphorites of Quercy (Lot, France) in the late 1960s. The exceptional preservation of the specimen allows us to describe the osteology, make substantial comparative observations and propose biological interpretations, leading to a partial reconstruction of the cranial vascularization, innervation, and musculature. We also reconstruct the ecological evolution of the European amphicyonids from the Paleogene based on their body masses and diets, leading to identify three different faunas: (1) the oldest one (Priabonian) is characterized by body mass around 10 kg, well-exemplified by Cynodictis lacustris; (2) the second (Rupelian) groups taxa from 30 to 50 kg; (3) the last one (Chattian) differs from the two others by the presence of large amphicyonids (ca. 140 kg) and the low number of hypercarnivorous amphicyonids. The in-depth investigation of this exceptional specimen provides new material for the systematic and paleoecological understanding of Paleogene amphicyonids.
The theropod dinosaur Coelophysis bauri is well known from the famous Rhaetian, Late Triassic mass death assemblage from the Coelophysis Quarry at Ghost Ranch, New Mexico. This research describes the skulls of two small individuals of C. bauri. Both skulls are mostly complete, though they are missing premaxillae, and most posterior skull bones are either missing or badly damaged. Both specimens preserve hyoids, making them excellent candidates for hyoid histology. These two skulls have different proportions from other Coelophysis skulls from Ghost Ranch, especially in the large size of the orbit, short and flat triangular teeth, and thinner bones. These differences are interpreted as representing ontogenetic variation, with these skulls representing skeletally immature, partially developed individuals.
Abstract In the wake of the greatest mass extinction in Earth’s history, the End-Permian Mass Extinction, the Triassic was a time of recovery and innovation. Aided by warm climatic conditions and favorable ecological circumstances, many reptilian clades originated and rapidly diversified during this time. This set the stage for numerous independent invasions of the marine realm by several reptilian clades, such as Ichthyosauriformes and Sauropterygia, shaping the oceanic ecosystems for the entire Mesozoic. Although comparatively less speciose, and temporally and latitudinally more restricted, another marine reptile clade, the Thalattosauriformes, stands out because of their unusual and highly disparate cranial, dental and skeletal morphology. Research on Thalattosauriformes has been hampered by a historic dearth of material, with the exception of rare material from Lagerstätten and highly fossiliferous localities, such as that from the UNESCO world heritage site of Monte San Giorgio. Consequently, their evolutionary origins and paleobiology remain poorly understood. The recent influx of new material from southwestern China and North America has renewed interest in this enigmatic group prompting the need for a detailed review of historic work and current views. The earliest representatives of the group may have been present from the late Early Triassic onwards in British Columbia. By the Ladinian the group had achieved a wide distribution across the northern hemisphere, spanning the eastern Panthalassic as well as the eastern and western Tethyan provinces. Distinct morphological and likely ecological differences exist between the two major clades of Thalattosauriformes, the Askeptosauroidea and the Thalattosauroidea, with the latter showing a higher degree of cranial and skeletal morphological disparity. In-group relationships remain poorly resolved beyond this bipartition. Overall, thalattosaurs may be closely related to other marine reptile groups such as ichthyopterygians and sauropterygians. However, their exact position within Diapsida remains elusive. Future focal points should utilize modern digital paleontological approaches to explore the many fragmentary specimens of otherwise poorly sampled localities.
Victoria E. McCoy, Jack Wittry, Hamed Sadabadi
et al.
AbstractNemavermes mackeei Schram, 1973, found in the Mazon Creek fossil site and the Bear Gulch Limestone, was described initially as a free-living marine nematode. Here we investigate 13 specimens of N. mackeei from the Mazon Creek to reassess its morphology and identity, and also two specimens originally identified as Gilpichthys greenei Bardack and Richardson, 1977. Based on the extensive morphological variation among these specimens, N. mackeei encompasses multiple species that are only distantly related. The holotype of N. mackeei is a proboscis of Tullimonstrum gregarium Richardson, 1966, making N. mackeei a junior synonym of T. gregarium. However, the other specimens that we investigated could not be attributed to T. gregarium. We name a new species from these specimens: Squirmarius testai new genus new species, a cyclostome. One specimen is likely a juvenile G. greenei. Other specimens were not identified during this study but represent a variety of vermiform bilaterians.UUID: http://zoobank.org/d8c63f6a-0ef4-4a34-8dbd-c1d9099589cc
Species of the cellariid genus Melicerita Milne Edwards develop bilaminar flattened colonies consisting of alternate transverse rows of hexagonal zooids. In South America, its stratigraphic range extends from the early Miocene to the Recent. Re-examination of the type material of M. triforis Ortmann from the Monte León Formation at Río Chalía, and scanning electron microscope images of M. ortmanni Canu from the early Miocene Chenque Formation, confirmed that the latter is a junior synonym of M. triforis. Vicarious avicularia are described for the first time in M. triforis. Lectotypes are herein chosen for both nominal species. M. imperforata sp. nov. is described from material obtained in Monte León Formation (early Miocene). It differs from all known Melicerita species in the size and shape of its vicarious avicularia, which are marginal and much larger than the autozooids. The Recent Magellanic species M. temaukeli Moyano and M. blancoae López Gappa share morphological similarities with M. triforis.
The larger-bodied fish fauna of the Kishenehn Formation’s Coal Creek Member (Eocene, 43.5 Ma), northwestern
Montana, is understudied because of a sampling bias towards small specimens. Small specimens (<10 cm length) of taxa
are usually found as mostly to fully complete compression fossils. Relatively larger-bodied fishes, such as amiids (the
bowfin Amia calva and close relatives), are only known from fragmentary remains for which taxonomic resolution is
only possible to the family level. Here we describe the most complete amiid fossil (USNM 618000) from the Kishenehn
Formation. We assign this specimen to the genus Amia based on the presence of pointed coronoid teeth and a long preural
region (81 preural centra). The specimen exhibits a combination of features from multiple species, including a total of
89 centra (like Amia calva and Amia scutata), eight ural centra (like Amia scutata and Amia pattersoni), and a concave
anteroventral margin on the first postinfraorbital (like Amia hesperia). The lack of more complete specimens of amiids
and other larger-bodied taxa is most often attributed to a preservation bias; however, this could also reflect a rarity of
amiids in the ecosystem overall or a partitioning of habitat preference away from the shallow, near-shore regions of the
ancient lake. This new specimen enhances the known biodiversity of relatively larger-bodied fishes from this region
during the Eocene epoch.
Deepa Agnihotri, Jorge F. Genise, Anju Saxena
et al.
AbstractThe new invertebrate trace fossil from paleosols of the Bijori Formation,Palliedaphichnium gondwanicumnew ichnogenus new ichnospecies, which belongs to an upper Permian Gondwana sequence of India, makes a significant contribution to the meager records of invertebrate trace fossils from Permian and Indian paleosols. This trace fossil attributed to Diplopoda and composed of tunnels and chambers filled with pellets is also an important addition to the scarce record of Permian millipedes. The abundance of plant remains in the same paleosol indicates that these millipedes probably fed on leaf litter as other fossil and extant representatives. Chambers and abundant pellets in burrows indicate adverse conditions on the surface, at least seasonally. This finding contributes to the emerging scenario of invertebrate ichnofaunas from paleosols and points to a successive dominance of millipedes during the Paleozoic, crayfishes and earthworms in the Mesozoic, and insects in the Cenozoic.UUID:http://zoobank.org/4378c739-9bd1-4382-b084-e2176045e209
AbstractPolykampton recurvumn. isp. is the sixth ichnospecies of the ichnogenusPolykamptonOoster, 1869. It is a horizontal structure composed of a median cylindrical tunnel and narrow, usually back-curved lateral lobes located in alternating position. It occurs 2–3 cm below the top of single beds in the Maastrichtian–Paleocene deep-sea turbiditic marlstones of the Monte Antola Unit in the Northern Apennines. The lobes ofP. recurvumn. isp. are actively filled with gray mudstone from above through the permanently open median tunnel. The trace fossil belongs to the category sequestrichnia, which is typical of oxygenated deep-sea environments characterized by seasonal or episodic supply of organic matter into a generally oligotrophic environment.P. recurvumn. isp. was produced by a “worm,” probably a polychaete, which adapted to seasonal or only episodic supply of organic matter to the deep-sea floor. The tracemaker stored the organic-rich mud in the lobes for nutrition during times of low organic matter availability on the seafloor.UUID:http://zoobank.org/49555117-1c39-4658-8b49-3f3e2f47ba27
The extinct vizcacha Lagostomus incisus is a particular rodent recorded in Pliocene sediments of Buenos Aires Province (Argentina), including the montehermosan “Irenean” Fauna and Monte Hermoso Formation, and the chapadmalalan Chapadmalal Formation. Its characteristic skull and cheek teeth anatomy permit to easily identify it even with fragmentary material. In this work, the fossil record of L. incisus is reassessed, being recognized in several units where it had not been reported before: the Unit B of the Saldungaray Formation, the Quequén Grande Local Fauna, and the Barker Formation in Buenos Aires Province (Argentina), and the San José Member of the Raigón Formation in Maldonado Department (Uruguay). These new records extend the distribution of L. incisus to most of central Buenos Aires Province in Argentina and southern Uruguay. Additionally, the recent radiometric dates of some of the units with records of L. incisus permit to confidently limit the temporal range of this species to the late early–early late Pliocene.
Alejandro Otero, Agustín Pérez Moreno, Peter Falkingham
et al.
Three-dimensional (3D) surface scanning includes techniques of image acquisition and image processing. Among the former, hardware devices (e.g., portable and non- portable scanners, camera) capture images from the target, whereas image processing is conducted via specialized software, in which acquired images are processed to merge them into a single 3D model. Image surface scanning include a wide variety of devices which incorporate different image acquisition techniques, all of them with potential high standards results. We describe different scanning devices and techniques commonly used in Vertebrate Paleontology in order to compare them in terms of pros and cons, considering different variables, such as scanning time, post-processing time, costs and image resolution. The decision on which device to choose will depend on the budget available, the portability as well as the nature of the fossil material being analyzed (e.g., size, weight, accessibility). In the light of this, photogrammetry constitutes the image surface technique which fulfils these requirements, having the best cost-benefit relationship.
Song Xing, María Martinón-Torres, José María Bermúdez de Castro
AbstractThis study provides new original data, including the endostructure of most Zhoukoudian H. erectus teeth preserved to date, since the publication of Black in 1927 and Weidenreich in 1937. The new evidence ratifies the similarities of Zhoukoudian with other East Asian mid-Middle Pleistocene hominins such as Hexian and Yiyuan, and allows defining a dental pattern potentially characteristic of this population commonly referred to as classic H. erectus. Given the possible chronological overlaps of classic H. erectus with other archaic Homo, the characterization of this group becomes a key issue when deciphering the taxonomy and evolutionary scenario of the Middle Pleistocene hominins in East Asia. Internally, the most remarkable feature of Zhoukoudian teeth is the highly crenulated enamel-dentine junction (EDJ) and its imprint on the roof of the pulp cavity. So far, this “dendrite-like” EDJ has been found only in East Asia Middle Pleistocene hominins although a large group of samples were assessed, and it could be useful to dentally define classic H. erectus in China. The crenulated EDJ surface, together with the stout roots and the taurodontism could be a mechanism to withstand high biomechanical demand despite a general dentognathic reduction, particularly of the crowns, in these populations.
The morphology and ontogeny of the trilobite Changaspis elongata based on 216 specimens collected from the Lazizhai section of the Balang Formation (Stage 4, Series 2 of the Cambrian) in Guizhou Province, South China are described. The relatively continuous ontogenetic series reveals morphological changes, and shows that the species has seventeen thoracic segments in the holaspid period, instead of the sixteen as previously suggested. The development of the pygidial segments shows that their number gradually decreases during ontogeny. A new dataset of well-preserved specimens offers a unique opportunity to investigate developmental traits after segment addition is completed. The ontogenetic size progressions for the lengths of cephalon and trunk show overall compliance with Dyar’s rule. As a result of different average growth rates for the lengths of cephalon, trunk and pygidium, the length of the thorax relative to the body shows a gradually increasing trend; however, the cephalon and pygidium follow the opposite trend. Morphometric analysis across fourteen post-embryonic stages reveals growth gradients with increasing values for each thoracic segment from anterior to posterior. The reconstruction of the development traits shows visualization of the changes in relative growth and segmentation for the different body parts. The new dataset and growth gradient of the trunk suggest that the thoracic segment growth dynamics of early Cambrian to Silurian trilobites follow the same general continuous, steady-state growth gradient decreasing from posterior to anterior.
Achelatan lobsters, also known as spiny and slipper lobsters, develop via a highly specialised larval form. This special larva, phyllosoma, is flat, translucent, possesses elongate legs and can grow to enormous sizes. Although these larvae may appear very fragile, they are well-known as fossils. Thousands of specimens have been found in the lithographic limestone of Southern Germany (Tithonian, Upper Jurassic, about 150 mya). At least three types of fossil, but modern-appearing phyllosoma larvae are known. Additionally, fossil larvae that possess only some of the characters of modern-day phyllosoma larvae are known from the same Lagerstätte, but also from the younger limestone beds of Lebanon. Here we report a new achelatan fossil from the older Posidonia Shale (Toarcian, Lower Jurassic, 175–183 mya). The specimen shows certain characters of a phyllosoma larva, but other characters appear like those of post-phyllosoma stages of achelatan lobsters. This specimen is therefore the oldest occurrence of an achelatan lobster larva. We compare the new specimen with other fossil larvae with such mixed or “intermetamorphic” morphologies.
Stephen Pates, Allison C. Daley, Javier Ortega-Hernández
As part of a comprehensive examination of all radiodontans from Cambrian localities in the USA, Pates et al. (2017a, b) and Pates and Daley (2017) revised the taxonomic affinities of several described specimens. This included the reinterpretation of two putative lobopodians, one from the Wheeler Formation (Utah, USA) and one from the Valdemiedes Formation (Spain), as frontal appendages of the radiodontan genera Stanleycaris and Caryosyntrips respectively. In their comment, Gámez Vintaned and Zhuravlev (2018) disagree with these conclusions and raise three topics for discussion: (i) anatomical features they suggest support a lobopodian affinity for “Mureropodia”; (ii) the identity of Caryosyntrips as a radiodontan, and the assignment of certain specimens to this genus; and (iii) the nomenclatural status of Stanleycaris hirpex as an invalid taxon. For (i), we dispute that the anatomical features put forward by Gámez Vintaned and Zhuravlev (2018) are biological and conclude that a lobopodian affinity for Mureropodia is untenable. In response to (ii), we provide further evidence supporting a radiodontan affinity for Caryosyntrips, and those specimens ascribed to this genus. Finally, we concur with (iii) Stanleycaris as an invalid taxon according to the International Code on Zoological Nomenclature (ICZN), and have rectified the situation by providing a valid systematic description.