Paleontological Area Research Articles

Juvenile notosuchian crocodiles from the La Buitrera Paleontological area with comments on qualitative ontogenetic characters

ABSTRACT Araripesuchus is a genus of medium-sized (approximately 1 m long) terrestrial uruguaysuchid crocodyliforms that lived during the Cretaceous in Gondwana. There is limited information about juvenile notosuchian specimens due to the scarcity of well-preserved fossils from ontogenetic series. This study presents a comprehensive morphological description of three juvenile specimens of Araripesuchus (MPCA PV 259, 624, and 1193) from the La Buitrera Paleontological Area, Patagonia, Argentina. These early developmental-stage specimens were identified at a generic level due to the absence of mature anatomical characters for precise classification. Variations were observed between these juveniles and the previously examined adult specimens from the same region. As a result, a list of characters indicating ontogenetic variants was provided. These characters represent discrete traits that vary throughout the life of the individuals and could serve as ontogenetic indicators. This study offers a deeper understanding of the skeletal anatomy of Araripesuchus and its range of morphological variation, providing new data for the characterisation of the genus and potential new taxa of uruguaysuchids.

Dinosaur tracks with skin impressions in the La Buitrera Paleontological Area (Candeleros Formation, Cenomanian), Río Negro Province, Argentina

The La Buitrera Paleontological Area, in the north of the Río Negro Province, Argentina, preserves the uppermost section of the Cenomanian Candeleros Formation, as well as a rich vertebrate fauna that inhabited the Kokorkom Desert paleo-erg. Candia Halupczok et al. (2017) reported tracks found on wet and dry interdune. New evidence from 2020 to 2022 fieldtrips enabled the recognition of tracks in cross-section in non-channelized ephemeral fluvial dominated facies within the main aeolian setting located in the vicinity of the wettest recorded area of the La Buitrera Locality: the Cañadón de las Tortugas. The cross-section tracks commonly identified in these facies are from 30 to 75 cm long and 20–30 cm deep. Some of them preserve thin and shallow structures in the filling of the original track wall interpreted here as traces of the trackmaker integument. Specimens preserve two kinds of skin impressions. The first ones are parallel, mostly oblique striations, which sometimes cross each other at a high angle, produced by the pes during penetration and withdrawal from the substrate. The second ones are subrounded to polygonal, here interpreted as scale traces of the sole foot. Two clear, subtriangular to curved, and elongated, claw impressions are recorded in one track that allow us to relate it with a sauropod trackmaker.

Discovering a Project for the Development of Geotourism in Rural Areas: The Paleontological and Archaeological Interpretation Centre of Tamajón (CIPAT, Guadalajara, Spain)

The important paleontological and archaeological discoveries made in Tamajón in recent years have enriched the exceptional natural and cultural heritage of this town in the north of the Guadalajara province (central Spain). The extraordinary educational and outreach value of these findings led the PaleoIbérica Research Group to develop a project for the design and creation of the Paleontological and Archaeological Interpretation Centre of Tamajón (CIPAT, acronym in Spanish). In this new space, students and the general public have access to knowledge of the past of the region through three exhibition and didactic areas and the support of a rigorous and engaging infographic. The Paleontological Area allows visitors to explore, through fossils, replicas, models (real and virtual) and dioramas, the diversity of coastal and marine life that inhabited the region during the Late Cretaceous Age. Moreover, the area highlights crocodylomorphs, dinosaurs and fishes (identified through their fossilized tracks), and the remains of plants and invertebrates. The Archaeological Area shows the origin and uses of the building material known as Tamajón Stone by means of rough or carved samples, tools traditionally used in its extraction and carving, and historical photographs. Furthermore, in the Didactic Area, innovative specific educational activities are carried out, facilitating the knowledge and appreciation of the rich natural and cultural heritage of Tamajón. After its recent inauguration (August 2021), the CIPAT is a valuable tool to encourage the practice of positive attitudes toward geoconservation and to promote the sustainable and socioeconomic development of the region through geotourism.

Earliest Tuatara Relative (Lepidosauria: Sphenodontinae) from Southern Continents

The New Zealand tuatara (Sphenodon) is the sole surviving rhynchocephalian of a once thriving group across Pangea during early Mesozoic times. Outside New Zealand, close relatives of the tuatara (sphenodontines) are known from a few Jurassic records in North America and Europe and from end-Cretaceous incomplete remains in Patagonia. Still, the evolutionary relationships of most of them remain elusive. Here we describe a new sphenodontine, Tika giacchinoi gen. et sp. nov., based on well-preserved cranial and postcranial remains from upper levels of the Candeleros Formation (Cenomanian) at the Konservat-Lagerstätte of ‘La Buitrera Paleontological Area’ in northern Patagonia, Argentina. Our phylogenetic analysis recovered Tika as a close relative of the tuatara, together with Laurasian and Patagonian taxa. The new finding represents the oldest certain sphenodontine from the gondwanan continents and reinforces the hypothesis that particular terrestrial ectothermic tetrapods attained a circumantarctic Cretaceous-Tertiary distribution. Tika is inferred to have fed upon a variety of prey items including small vertebrates, similar to the extant tuatara, but ecologically different from the large herbivorous sphenodontians already known from La Buitrera. Therefore the new taxon expands the known diversity of sphenodontians during the Late Cretaceous in Patagonia and indicates that Rhynchocephalia, although declining or extinct in Laurasia, were still taxonomic and ecologically diverse in southwestern Gondwana.

A preliminary report of the fossil mammals from a new microvertebrate locality in the Upper Jurassic Morrison Formation, Grand County, Utah

The first Mesozoic mammals in North America were discovered in the Morrison Formation during the closing decades of the 19th century, as by-products of dinosaurs quarried by teams led by O.C. Marsh. These tiny fossils served as foundational specimens for our understanding of Mesozoic mammal evolution. There are now nearly 25 mammal-bearing localities known from the Morrison Formation, distributed across the Western Interior from the Black Hills to southern Colorado and west into Utah; the most historically important of these are in Wyoming (e.g., Como Quarry 9). Most Morrison mammals are known by jaws or jaw fragments, and several important Mesozoic groups (e.g., docodonts, dryolestoids, and to a large extent triconodonts and symmetrodonts) were established based on Morrison material, shaping the perception of mammalian diversity on a global scale. Despite heavy sampling of coeval sites elsewhere, the Morrison remains the most systematically diverse (at high taxonomic levels) assemblage of Jurassic mammals in the world. Here, we describe two mammalian specimens and highlight other remains yet to be fully identified from a new microvertebrate locality in the Morrison Formation of eastern Grand County, Utah. The site is positioned low in the Brushy Basin Member and is similar in lithology and stratigraphic level to the famous small vertebrate localities of the Fruita Paleontological Area, located less than 50 km to the northeast. In addition to small archosaurs and squamates, limited excavation to date has yielded at least 20 mammalian specimens representing a minimum of six taxa, several of which are new and quite different from typical Morrison taxa. Preservation is generally excellent and includes partially articulated cranial and postcranial elements of small vertebrates. This new site has great potential to contribute new taxa and more complete morphological data than typical Morrison localities, underscoring the importance of continued field work in the Morrison.

A preliminary report of the fossil mammals from a new microvertebrate locality in the Upper Jurassic Morrison Formation, Grand County, Utah

The first Mesozoic mammals in North America were discovered in the Morrison Formation during the closing decades of the 19th century, as by-products of dinosaurs quarried by teams led by O.C. Marsh. These tiny fossils served as foundational specimens for our understanding of Mesozoic mammal evolution. There are now nearly 25 mammal-bearing localities known from the Morrison Formation, distributed across the Western Interior from the Black Hills to southern Colorado and west into Utah; the most historically important of these are in Wyoming (e.g., Como Quarry 9). Most Morrison mammals are known by jaws or jaw fragments, and several important Mesozoic groups (e.g., docodonts, dryolestoids, and to a large extent triconodonts and symmetrodonts) were established based on Morrison material, shaping the perception of mammalian diversity on a global scale. Despite heavy sampling of coeval sites elsewhere, the Morrison remains the most systematically diverse (at high taxonomic levels) assemblage of Jurassic mammals in the world. Here, we describe two mammalian specimens and highlight other remains yet to be fully identified from a new microvertebrate locality in the Morrison Formation of eastern Grand County, Utah. The site is positioned low in the Brushy Basin Member and is similar in lithology and stratigraphic level to the famous small vertebrate localities of the Fruita Paleontological Area, located less than 50 km to the northeast. In addition to small archosaurs and squamates, limited excavation to date has yielded at least 20 mammalian specimens representing a minimum of six taxa, several of which are new and quite different from typical Morrison taxa. Preservation is generally excellent and includes partially articulated cranial and postcranial elements of small vertebrates. This new site has great potential to contribute new taxa and more complete morphological data than typical Morrison localities, underscoring the importance of continued field work in the Morrison.

Life of Niels Stensen (1638-1686), who was the Pioneer Scientist and Great Neuroanatomist

Danish scientist, Niels Stensen was a prosperous anatomist and in addition to that a pioneer in the areas of paleontology, geology, mineralogy and bishop. With his studies on subjects of anatomy, neuroscience, paleontology, mineralogy and geology Niels Stensen has major scientific contributions despite the difficult circumstances until his death at very young age.

Major bonebeds in mudrocks of the Morrison Formation (Upper Jurassic), northern Colorado Plateau of Utah and Colorado

The Morrison Formation contains a number of large quarries that have yielded dinosaurs and other vertebrates, and many of these occur in sandstone beds representing ancient river channels. However, a number of very productive sites occur in mudstone beds representing other environments such as ephemeral ponds, and some of these yield both large dinosaurs and microvertebrates; these localities in mudstone beds represent different taphonomic modes of preservation and often preserve vertebrate taxa in different relative abundances from the channel sandstone sites. Among these important and very productive mudstone localities are the Cleveland-Lloyd Quarry, the Mygatt-Moore Quarry, and the microvertebrate sites of the Fruita Paleontological Area, and each of these preserves distinct vertebrate paleofaunas, different from sandstone sites and from each other, suggesting that mudstone localities had a very different mode of sampling the local biotas than did sites in sandstone.

Major bonebeds in mudrocks of the Morrison Formation (Upper Jurassic), northern Colorado Plateau of Utah and Colorado

The Morrison Formation contains a number of large quarries that have yielded dinosaurs and other vertebrates, and many of these occur in sandstone beds representing ancient river channels. However, a number of very productive sites occur in mudstone beds representing other environments such as ephemeral ponds, and some of these yield both large dinosaurs and microvertebrates; these localities in mudstone beds represent different taphonomic modes of preservation and often preserve vertebrate taxa in different relative abundances from the channel sandstone sites. Among these important and very productive mudstone localities are the Cleveland-Lloyd Quarry, the Mygatt-Moore Quarry, and the microvertebrate sites of the Fruita Paleontological Area, and each of these preserves distinct vertebrate paleofaunas, different from sandstone sites and from each other, suggesting that mudstone localities had a very different mode of sampling the local biotas than did sites in sandstone.

A new cercopithecoid dentognathic specimen attributed to Theropithecus from the late Early Pleistocene (c. 1 Ma) deposits of Simbiro, at Melka Kunture, Ethiopian highlands

The archeological and paleontological area of Melka Kunture, in the Ethiopian highlands, has yielded particularly rich mammal fossil assemblages, including a few human and nonhuman primate remains. The cercopithecoid specimens reported so far consist of a fragmentary lower third molar crown and of a maxillary fragment, coming from the Early Pleistocene sites of Garba IV and Garba XII, respectively. In this study we describe an additional dentognathic specimen, labelled SIM III-13-1, collected in 2013 in the c. 1 Ma sedimentary deposits of Simbiro. In addition to classical descriptions and measurements, this specimen was detailed by X-ray tomography (CT) and two-three dimensional (2–3D) quantitative analyses were performed on the virtual reconstruction to assess its taxonomic assignment. Comparison with a number of fossil and extant cercopithecoid specimens/samples suggests that SIM III-13-1 belongs to the genus Theropithecus, more likely to Theropithecus sp. cf. oswaldi.

Mammalian Petrosal from the Upper Jurassic Morrison Formation of Fruita, Colorado

ABSTRACT A partial petrosal from the Upper Jurassic Morrison Formation of the Fruita Paleontological Area of western Colorado preserving the pars cochlearis and part of the pars canalicularis is described. The endocast of the inner ear showing the cochlea, vestibule, lateral semicircular canal, and the terminal ends of the anterior and posterior semicircular canals is reconstructed from µCT scans. This specimen is only the fourth petrosal known from the Morrison Formation. Mammals known from Fruita include Fruitafossor windsheffeli Luo and Wible, 2005, the triconodontid Priacodon fruitaensis Rasmussen and Callison, 1981, the plagiaulacoid multituberculate Glirodon grandis Engelmann and Callison, 1999, and unnamed spalacotheriids and dryolestoids. The partial petrosal and its endocast share significant features with dryolestoids from the Upper Jurassic of Guimarota, Portugal, including a separate fenestra cochleae and cochlear canaliculus, and a cochlea that is coiled more than 200°. In light of these simi...

A new shartegosuchid crocodyliform from the Upper Jurassic Morrison Formation of western Colorado

A small new basal crocodyliform, Fruitachampsa callisoni gen. nov., sp. nov., is represented by several partial skeletons from the Morrison Formation at the Fruita Paleontological Area near Grand Junction, Colorado. It is placed in the Family Shartegosuchidae Efimov, 1988, previously comprising three genera from the Late Jurassic locality of Shar Teeg in western Mongolia and possibly a fourth genus from the Early Cretaceous of Siberia. Shartegosuchids share a sculpted palatal surface of the pterygoids, the absence of a mandibular fenestra, and posterior maxillary teeth and post-caniniform dentary teeth with a flat and horizontal apical region and vertical crenulations extending basally from it. Fruitachampsa and Shartegosuchus form a clade supported by ventral half of the lacrimal tapering ventroposteriorly, sculpturing on palatines, and lower teeth absent anterior to caniniforms. The shartegosuchids are most parsimoniously considered to be outside of the mesoeucrocodylian clade and are possibly allied with the Asian taxa Shantungosuchus, Sichuanosuchus, and Zosuchus. Fruitachampsa is unusual in possessing a series of small protuberances along the occipital margin of the parietal and squamosal and procoelous vertebrae, and lacking an antorbital fenestra or fossa. This is the first occurrence of a shartegosuchid in North America, and the close relationship of Fruitachampsa with Shartegosuchus nested among other Asian taxa indicates it dispersed to North America from Asia.

Centro de Pesquisa de História Natural e Arqueologia do Maranhão

The Research Center of Natural History and Archaeology of Maranhão – CPHNAMA, linked to the State Secretary of Culture, has as objective to promote the study, valorization andpreservation of Maranhão patrimonial heritage, specifically the archaeological and palaeontological resources and assetsand the material culture and traditions of indigenous peoples. Besides the systematic development of research activities inthe areas of Paleontology, Archaeology and Ethnology, it develops patrimonial education-focused actions through the preparation, organization and execution of exhibitions, cultural events, exhibitions, seminars, lectures and classes for different audiences.

Popular Interest Fuels a Dinosaur Research Boom

PALEONTOLOGYPaleontologists are learning to capitalize on the popularity of dinosaurs, and new discoveries, labs, and exhibits are the result. A new analysis suggests that the number of dinosaur papers is on the rise, and new positions are appearing at a time when other areas of paleontology are barely holding steady. Spectacular fossil discoveries follow one upon the other, including an African specimen with a fish-eating, crocodilelike skull, described on page [1298][1] of this issue. But despite all the activity, few researchers are flush with funds. [1]: http://www.sciencemag.org/cgi/content/short/282/5392/1298

Trilobite Taphonomy and Taxonomy: A Problem and Some Implications

Recent advances in trilobite taphonomy have highlighted the importance of sclerite preservation for understanding sedimentary processes and aspects of trilobite paleoecology (Speyer and Brett, 1985, 1986; Westrop, 1986; Babcock and Speyer, 1987; Speyer, 1987, 1988). The effect of taphonomy on trilobite taxonomy has received less attention. Consequently, it is not possible to evaluate the broader effects of taphonomy on our understanding of evolution and biogeography, and some recent studies of evolutionary patterns within the group (e.g., Foote, 1990, 1991, 1993) have been restricted to forms occurring within particular lithofacies. Numerous systematic papers discuss how preservation affects particular characters or character sets. Examples include the effects of compaction on sclerite morphology in specimens preserved in fine grain clastic sediments (e.g., Kiaer, 1917; Fortey, 1974), differences between carbonate and clastic preservation (e.g., Taylor, 1978), the differences in the morphology of internal and external molds (e.g., Jell, 1985), and how taphonomic artifacts have been mistaken for biological features (Hughes, 1993). However, such examples refer to specific instances, and are of limited use in evaluating the broader implications of taphonomy on trilobite taxonomy. As taphonomic conditions vary markedly between sedimentary environments, the effects of taphonomy on trilobite systematics are likely to be greatest on those taxa which occur in a wide range of lithofacies. Such taxa are often the most useful for providing inter-regional correlations and hence have critical significance for biogeography and biostratigraphy. Here I present a brief illustrative example of the potential effects of taphonomy on the taxonomy of one trilobite, the middle Cambrian conocoryphid Bailiella, and a discussion of the implications of this example for other areas of paleontology. Bailiella is an appropriate trilobite to use as an example for several reasons. Firstly, as an eyeless conocoryphid trilobite its morphology is distinct from that of many generalized ptychopariid trilobites, with which it is co-occurrent. Its distinctiveness allows us to be relatively confident of its identification, despite the taphonomic differences detailed below. Secondly, the genus is widespread and occurs in a variety of paleoenvironments. A revision of the systematics of Bailiella species from China, Vietnam, India and Siberia, indicates that the position of the facial suture (cutting the border) provides a consistent characteristic that can be used to recognize the species B. lantenoisi (see Zhang and Jell, 1987, pl. 35, figs. 1-7). This species is found both in shelfal carbonate settings (China and Siberia), where it is usually found as disarticulated sclerites, and in finegrain clastic slope deposits (Vietnam and India) where it occurs both as articulated dorsal shields and as disarticulated sclerites. These different preservation styles present alternative character suites to the systematist. For example, cranidia preserved in carbonates possess original relief and fine details of surface ornament. The preservation potential of these types of features is reduced in specimens preserved in shales, because the skeletal material is often absent and the specimens are compressed composite molds. The presence of articulated dorsal exoskeletons in this type of setting, however, provides a suite of characteristics that are not available for evaluation in specimens from shelf carbonates. Such characteristics include the number of thoracic segments, and the overall body proportions. Peter Jell and I are preparing a redescription of B. lantenoisi that lists some 38 major characters (Table 1). Parentheses are used here because the question of what constitutes a character is subjective in any systematic analysis (see Adrain and Chatterton, 1990), and character choice is especially difficult when the morphology includes both biological and preservational components. Another systematist would not describe an identical set of characters, but the magnitude of preservational factors documented below far outweighs slight differences of character interpretation. The greater number of characters listed for the cranidium (23) than for the remainder of the dorsal exoskeleton (15) (Table 1) reflects the concentration of distinctive morphological features on that sclerite. Of the 38 characters, only 14 appear to have resisted modification by preservational biases, and can be compared with confidence in specimens from all lithofacies settings (Table 1). Variation in any of these 14 characters could potentially be used to define different taxa, but apparently does not do so in this case. Of the remaining 24 characters we can be less confident. 18 characteristics can only be coded with confidence in specimens from carbonates preserving relief and fine detail, 4 are codable only in articulated dorsal shields, presently known only from slope settings, and 2 cannot be coded with confidence in either setting. Each of these 24 characteristics could potentially indicate taxonomic differences between B. lantenoisi collections preserved in different taphonomic settings. However, as these

Dinosaurs, Nuclear Winter, and Kanizsa Figures: In Defense of Pure Science and Intellectual Curiosity

The practical implications of the nuclear winter scenario have been widely discussed. This scenario offers an elegant example of the application of several lines of pure research to a pressing real-world problem. Before the recent synthesis of findings in the areas of paleontology, historical geology, and astronomy, it was not obvious that research in any of these areas—particularly on the extinction of the dinosaurs about 65 million years ago—would ever have the slightest bearing on the question of the possible self-destruction of the human species, perhaps the most pressing issue of our time. Similarly, it is not always obvious which avenues of pure research in psychology might turn out to have unexpected applications in the real world.

Vertebrate paleoecology: A current perspective

Vertebrate paleoecology, a study with a long history, has thrived during the last four decades and has become the focal point of intensive investigation since about 1965. It has followed a somewhat different course from studies of marine invertebrate paleoecology questions about the utility, validity and relationships of paleoecology to ecology continue to be raised and discussed. Paleoecology draws on and contributes to essentially all areas of paleontology. Several subdisciplines in which there has been particularly intensive investigation are singled out for discussion. Taphonomy lies at the base of all paleoecological studies for, along with systematic analysis, it provides the basic data upon which all reconstructions of the living biota are made from the fossil deposits to which they contributed. Very active in development of taphonomy have been the students of Paleoecology of the Hominidae. This area of study has passed from a dominance of speculation in the first decades of this century to objective analysis based upon the application of biological principles, extended and detailed field work, and current evolutionary concepts to the evolution of the family Hominidae. Extinctions have recently received extensive analyses, with emphasis on mass extinctions such as that at the Cretaceous-Tertiary boundary. The analyses have extended the uses of taphonomic research into the difficult areas of time intervals generally not available in the fossil record. Physiological-Ecological and Behavioral studies are casting new light upon the problems of interpretation of extinct animals which lack close living counterparts. Community Structure has been of special interest among terrestrial vertebrates since the early 1950's. It's study has required reinterpretations of samples and sampling procedures and development of models to aid in analysis of the biases in fossil assemblages. Both community types and substantive communities have received careful attention, including pragmatic definitions, studies of the use of analogies and introspection on possible contributions to ecology as whole. Such researches have been elaborated into studies of the relationships communities through time under the general heading of Community Evolution. Problems of evolution in a slowly changing community and in the evolution of new community types have been central themes in this area.

Numerical analysis and group formation in palynology

Abstract All areas of paleontology are experiencing a rapid rise in the use of statistical treatments of data, and palynology is no exception. The range of these treatments open to palynologists is great; however all involve (1) putting the data into a format wherein it can be analyzed statistically, (2) performing the statistical test, and (3) transforming the numerical results of the test into a format from which interpretation can be made. It should be possible to choose approaches at all three of these stages which maximize the information which can be obtained, while taking into consideration the special problems inherent in palynology, such as the extreme transportability of palynomorphs and the differential production of pollen and spores by different species of plants. This study compares several different statistical approaches to a specific palynological problem drawn from the Permian of Oklahoma, pointing out the advantages and disadvantages of the various methods. It suggests that the most mea...