Rare Fossils Research Articles

Novel pterygotid sea scorpions from the Silurian and Devonian of Gondwana

Sea scorpions (eurypterids) are a group of extinct aquatic chelicerates that have a fossil record spanning the Ordovician through to the end Permian extinction. Due to their size and preservational potential, eurypterids have been well-documented in European and North American deposits, with less evidence from Gondwana. There is particularly limited evidence of the group from the Australian fossil record. To rectify this, we report new examples of pterygotid eurypterids from the late Silurian Wallace Shale and Early Devonian Merrimerriwa Formation, Mulga Downs Group in New South Wales. These specimens are assigned to Pterygotus sp. (Wallace Shale) and Jaekelopterus c.f. rhenaniae (Merrimerriwa Formation, Mulga Downs Group). The material is used to explore the extensive distribution and dispersal of these large, pelagic eurypterids and consider the position of the animals in their respective paleoecosystems. We conclude that these new records evidence the diversity of larger arthropods in Australian deposits and that ongoing documentation of these rare fossils is required to further understand the Paleozoic of Australia.

Two new species of Tasiocera Skuse from Baltic amber (Diptera, Limoniidae)

The paper presents very rare fossil record of crane flies. Inclusions in Baltic amber have documented the second evidence of the existence of the genus Tasiocera (Diptera: Limoniidae: Chioneinae) in ancient epochs of Earth’s history. Hypotheses were also introduced regarding the environmental preferences of fossil Dasymolopilus in relation to modern representatives of the subgenus. The genus is numerous in species and widespread in the modern fauna, while only one species, Tasiocera (Dasymolophilus) circumcincta, has been known from the fossil record to date. The paper presents an additional description and graphic documentation of this species based on new materials. The discovery of two other species Tasiocera (Dasymolophilus) gorskii sp. nov. and Tasiocera (Dasymolophilus) baltica sp. nov. in Eocene resins documents the occurence of Tasiocera since Eocene. Interestingly, only subgenus Dasymolophilus is represented both in extinct and extant fauna while subgenus Tasiocera is not known from the fossil record. The new discovery is very significant, and the result of the study adds a brick to our understanding of the evolution of this group of insects and their habitat.

Detection of intact polyene pigments in Miocene gastropod shells

AbstractPolyene pigments represent a major class of pigments in present‐day organisms. Their occurrence in fossils has been frequently discussed, but to date no spectroscopic evidence has been found. Here, we use in situ Raman spectroscopy to examine the chemistry of exceptionally well‐preserved gastropod shells with colour preservation from the Middle Miocene of the Vienna Basin (Austria, Hungary). Raman signals indicative of the presence of intact (i.e. non‐hydrogenated) polyene pigments were obtained from fossil shells with reddish colour patterns, thus revealing the first record of intact polyenes in fossils. The observed Raman values are in good agreement with those of unmethylated (non‐carotenoid) polyenes. Fossil polyene pigments were detected in representatives of the superfamily Cerithioidea, but not in representatives of other gastropod families with colour preservation found at the same localities, demonstrating that the occurrence of polyene pigments is taxon‐specific. Our results show that Raman spectroscopy represents a valuable tool for the non‐destructive screening of rare fossils with colour preservation for the occurrence of polyene pigments.

Fossil image identification using deep learning ensembles of data augmented multiviews

Abstract Identification of fossil species is crucial to evolutionary studies. Recent advances from deep learning have shown promising prospects in fossil image identification. However, the quantity and quality of labelled fossil images are often limited due to fossil preservation, conditioned sampling and expensive and inconsistent label annotation by domain experts, which pose great challenges to training deep learning‐based image classification models. To address these challenges, we follow the idea of the wisdom of crowds and propose a multiview ensemble framework, which collects Original (O), Grey (G) and Skeleton (S) views of each fossil image reflecting its different characteristics to train multiple base models, and then makes the final decision via soft voting. Experiments on the largest fusulinid dataset with 2400 images show that the proposed OGS consistently outperforms baselines (using a single model for each view), and obtains superior or comparable performance compared to OOO (using three base models for three the same Original views). Besides, as the training data decreases, the proposed framework achieves more gains. While considering the identification consistency estimation with respect to human experts, OGS receives the highest agreement with the original labels of dataset and with the re‐identifications of two human experts. The validation performance provides a quantitative estimation of consistency across different experts and genera. We conclude that the proposed framework can present state‐of‐the‐art performance in the fusulinid fossil identification case study. This framework is designed for general fossil identification and it is expected to see applications to other fossil datasets in future work. Notably, the result, which shows more performance gains as train set size decreases or over a smaller imbalance fossil dataset, suggests the potential application to identify rare fossil images. The proposed framework also demonstrates its potential for assessing and resolving inconsistencies in fossil identification.

Response of the Patagonian floras to climatic cooling during Oligocene−Miocene transition and the expansion of Antarctic glaciation

Pulses of Antarctic ice sheet expansion and associated climatic deterioration are thought to have driven major shifts in the world's flora during the Cenozoic Era. However, the rarity of fossils from well-constrained sedimentary strata in high palaeolatitudes makes it difficult to explore to these vegetation shifts directly. In this study, we infer changing patterns of floristic richness through the Oligocene−Miocene cooling event (∼23 Ma), based on analysis of terrestrial palynological samples in the radiometrically-constrained sediments of the Río Guillermo Formation of southern Patagonia. Our fossil assemblages include plant families typical of modern Magellanic subpolar forests such as Nothofagaceae, Podocarpaceae, Araucariaceae, and Myrtaceae. Adjusted for sample completeness (or coverage), our floristic richness estimates are, on average, higher than those from modern subpolar forests yet considerably lower than any other Paleogene or Neogene palynological records published elsewhere from the continent. The transient Oligocene−Miocene cooling episode, whose effects were probably intensified in southern Patagonia due to its close proximity to the glaciated Antarctic Peninsula, may have contributed to the steep decline in floristic richness. We infer that most Gondwanan plant relicts that survived across the Oligocene−Miocene transition endured through subsequent Neogene climatic fluctuations and contribute to present-day Magellanic subpolar forests. Our study highlights how precisely-dated fossil assemblages and robust diversity methods can be used to track biodiversity shifts in response to past climate change.

New remains of Dinocrocuta (Percrocutidae; Carnivora) from Markhal, Dhok Pathan Formation, Pakistan

ABSTRACT This paper describes a well-preserved left mandible of Dinocrocuta from a new fossil locality of Markhal area, Dhok Pathan Formation (Middle Siwaliks), Pakistan. The morphometric analysis of the studied materials with already known species of family Percrocutidae allows to attribute this specimen to Dinocrocuta grandis. The representation of this species exists in literature based on the already described materials, but it is the first description based on new fossil materials from the Siwaliks. In this regard, the discovery of a new material from the study area is important to resolve the generic attribution, stratigraphic range as well as the diversification of percrocutids in the Dhok Pathan Formation of the Siwaliks. Description of a new and rare fossil material from the Siwalik continental deposits is thus important to provide more information on percrocutids and to discuss its relationships with other species of genus Dinocrocuta, family Percrocutidae.

‘Dawn’ hexapods in Cenozoic ambers (Diplura: Campodeoidea)

Abstract Diplura are an ancient group of basal (apterygote) hexapods that thrive in various cryptic terrestrial habitats. Despite an ancient origin that extends at least to the Devonian period, the dipluran fossil record is exceedingly sparse. Here, we document five very rare fossil specimens of the family Campodeidae in amber from the Miocene of the Dominican Republic and the Eocene of the Baltic region. Microscopic preservation in amber provides unique detail for taxonomic placement of small, delicate, soil- and leaf litter-dwelling organisms like these. New taxa include the following: in Lepidocampinae, Lepidocampa glaesi sp. nov. (in Dominican amber); and in Campodeinae, Litocampa eobaltica sp. nov. (in Baltic amber) and Rostricampa engeli gen. et sp. nov. (in Dominican amber). Rostricampa has an extraordinary rostrum formed by sclerotized extensions of the clypeus and, probably, the labium, unique among diplurans. These new taxa provide rare additional data on the fossil record of the earliest diverging lineages of the hexapods and shed light on their evolution and ecology.

A new giant nautilid species from the Middle Jurassic of Luxembourg and Southwest Germany

In comparison to other cephalopods such as ammonites and belemnites, nautilid shells are relatively rare fossils in Jurassic marine deposits and knowledge of their taxonomy is therefore still patchy. We describe herein a new species of Cenoceras, C. rumelangense, from the early Bajocian Humphriesianum Zone of Luxembourg and Southwest Germany. In Luxembourg, the type material occurs in the ‘Marnes sableuses d’Audun-le-Tiche’ unit, which yields other large-sized cephalopods, such as the largest known belemnite genus, Megateuthis. The new species reaches a remarkable size, with diameters up to 610 mm. Thus, it is amongst the largest known post-Triassic nautilids worldwide, together with Paracenoceras giganteum and Paracenoceras ingens from the Upper Jurassic. Additionally, we discuss some aspects of the taphonomy of these large shells deposited in a shallow marine setting.

Thalattosuchian crocodylomorphs from European Russia, and new insights into metriorhynchid tooth serration evolution and their palaeolatitudinal distribution.

From the Middle Jurassic to the Early Cretaceous, metriorhynchid crocodylomorphs inhabited marine ecosystems across the European archipelago. Unfortunately, European metriorhynchids are only well known from Germany, France, and the UK, with the Eastern European fossil record being especially poor. This hinders our understanding of metriorhynchid biodiversity across these continuous seaways, and our ability to investigate provincialism. Here we describe eleven isolated tooth crowns and six vertebrae referable to Metriorhynchidae from the Callovian, Oxfordian, Volgian (Tithonian), and Ryazanian (Berriasian) or Valanginian of European Russia. We also describe an indeterminate thalattosuchian tooth from the lower Bajocian of the Volgograd Oblast, the first discovery of a marine reptile from the Bajocian strata of European Russia. These rare fossils, along with previous reports of Russian thalattosuchians, indicate that thalattosuchians have been common in the Middle Russian Sea since it was formed. Palaeolatitude calculations for worldwide metriorhynchid-bearing localities demonstrate that the occurrences in European Russia are the most northern, located mainly between 44-50 degrees north. However, metriorhynchids appear to be rare at these palaeolatitudes, and are absent from palaeolatitudes higher than 50°. These observations support the hypothesis that metriorhynchids evolved an elevated metabolism but were not endo-homeothermic, especially as endo-homeothermic marine reptiles (ichthyosaurs and plesiosaurs) remained abundant at much higher palaeolatitudes.

Aline Ghilardi: Fighting Against Colonialism and Sexism in Paleontology

The Brazilian scientist is one of the leading voices in the movement to bring a rare fossil back to Brazil.

Cambrian 'sap-sucking' molluscan radulae among small carbonaceous fossils (SCFs).

Molluscs have produced an extensive fossil record, owing to the prevalence of robust biomineralized shells among this clade. By contrast, most other components of molluscan anatomy are seldom preserved. Importantly, little is known of the evolutionary history of the unique molluscan feeding apparatus-the radula. A scarcity of fossil radulae has hampered our understanding of the ancestral condition, and of the dietary ecology of early molluscs. The handful of known fossil radulae all point to early molluscs as simple deposit feeders that obtained food via rasping or scraping. This study reports microscopic radulae preserved as 'small carbonaceous fossils' (SCFs) from Cambrian (Stage 4-Wuliuan, approximately 514-504.5 Ma) strata of Sweden. These rare fossil radulae offer novel insights into the feeding anatomy and ecology of early molluscs. Each radula comprises a uniseriate arc of (≤10) blade-shaped teeth, fringed by a slicing keel. This distinctive morphology is strikingly convergent with the radulae of extant sacoglossan heterobranch gastropods-such radulae are specially adapted for piercing the cell walls of green algal tissues to enable suctorial feeding on the cytoplasm contents. Discovery of analogous Cambrian radulae demonstrates this specialized form of herbivory had already evolved among molluscs more than half a billion years ago.

Middle Eocene (Lutetian-Bartonian) larger benthic foraminifera assemblages from Batman and Siirt (Southern Neotethys, SE Turkey): a new assessment

The benthic foraminifera assemblage has been described in the limestones outcropped in Kurtalan and Eruh district of Hoya formation which is one of autochthonous units of Arabian Platform (SE Turkey). From the two measured sections, one of them has rare fossil content due to dolomitization (DH-Dodan section),while the other is fairly remarkable in terms of fossil content (EH-Eruh section). The foraminiferal assemblages are represented by Asterigerina rotula (Kaufmann), Operculina ex. gr. gomezi Colom and Bauza, Victoriella conoidea Rutten, Amphistegina sp., Elphidium sp., Peneroplis sp., Carpenteria sp., Stomatorbina sp., miliolid and rotaliid forms and echinoderms, coral fragments in the Dodan section. The foraminiferal assemblages are represented by Nummulites biedai Schaub, Nummulites maximus d’Archiac, Nummulites perforatus de Montfort, Nummulites postfossulatus Sirel and Deveciler, Nummulites praeaturicus Schaub, Assilina exponens (Sowerby), Sphaerogypsina globulus (Reuss), Asterigerina rotula (Kaufmann), Lockhartia cf. hunti Ovey, Neoratlia sp., Operculina sp., Discocyclina sp., Asterocyclina sp., Lockhartia sp., Lenticulina sp., miliolid-rotaliid forms and echinoderms in the Eruh section. The fossil assemblage described shows that the limestones are of Lutetian-Bartonian and this assemblage indicates a very shallow marine deposition environment. This study provides biostratigraphic and stratigraphic data that help to reassess the Eocene geological evolution of the region. Paleobiogeographically, larger benthic foraminiferal assemblages recorded on carbonate platforms in southeastern Turkey show an affinity to Arabian and Middle Eastern platforms.

Recognition of Rare Microfossils Using Transfer Learning and Deep Residual Networks.

Various microfossils from the early Cambrian provide crucial clues for understanding the Cambrian explosion and the origin of animal phyla. However, specimens with important anatomical structures are extremely rare and the efficiency of retrieving such fossils by traditional manual selection under a microscope is quite low. Such a contradiction has hindered breakthroughs in micropaleontology for a long time. Here, we propose a solution for identifying specific taxa of Cambrian microfossils using only a few available specimens by transferring a model pre-trained on natural image datasets to the field of paleontological artificial intelligence. The method employs a 34-layer deep residual neural network as the underlying framework, migrates the ImageNet pre-trained model, freezes the low-layer network parameters and retrains the high-layer parameters to build a microfossil image recognition model. We built training sets with randomly selected images of varied number for each taxon. Our experiments show that the average recognition accuracy for specific taxa of Cambrian microfossils (50 images for each taxon) is higher than 0.97 and it can reach 0.85 with only three training samples per taxon. Comparative analyses indicate that our results are much better than those of various prevalent methods, such as the transpose convolutional neural network (TCNN). This demonstrates the feasibility of using natural images (ImageNet) for the training of microfossil recognition models and provides a promising tool for the discovery of rare fossils.

Crushed but not lost: a colubriform snake (Serpentes) from the Miocene Swiss Molasse, identified through the use of micro-CT scanning technology

An incomplete postcranial skeleton of a snake from the middle Miocene of the Swiss Molasse in Käpfnach mine, near Zurich, Switzerland, is described in this paper. The skeleton is rather crushed and resting on a block of coal, with only some articulated vertebrae partially discerned via visual microscopy. We conducted micro-CT scanning in the specimen and we digitally reconstructed the whole preserved vertebral column, allowing a direct and detailed observation of its vertebral morphology. Due to the flattened nature of the fossil specimen, several individual vertebral structures are deformed, not permitting thus a secure precise taxonomic identification. Accordingly, we only refer the specimen to as Colubriformes indet. Nevertheless, this occurrence adds to the exceedingly rare fossil record of snakes from Switzerland, which had so far been formally described solely from three other Eocene and Miocene localities.

Qurliqnoria (Mammalia: Bovidae) fossils from Qaidam Basin, Tibetan Plateau and deep-time endemism of the Tibetan antelope lineage

Abstract The Tibetan antelope (Pantholops hodgsonii) is an endemic bovid of the Tibetan Plateau, which was, until recently, considered an endangered species. Researchers have long speculated on the evolutionary origin of Pantholops, suggesting a connection to the rare fossil bovid Qurliqnoria. However, the lack of adequate fossil samples has prevented the testing of this deep-time endemism hypothesis for eight decades. Here, we report new fossils of Qurliqnoria cheni from the northern Tibetan Plateau, substantially increasing the amount of morphological data that can be brought to bear on the question of Tibetan antelope evolution. Phylogenetic analysis supports a Pantholops–Qurliqnoria clade and suggests that this lineage has been endemic to the Plateau for 11 Myr. Recent morphological and molecular studies that support the outgroup position of Pantholops relative to caprins (goats and relatives) and the fossil record of stem bovids from Europe together suggest that the Qurliqnoria–Pantholops lineage is likely to have dispersed to the Tibetan Plateau 15–11 Mya. Furthermore, the harsh environmental conditions to which Pantholops has adapted are likely to extend back to the time of its evolutionary origin. These findings provide an important new context for conservation management and research into the near-threatened Tibetan antelope, as the longest-living endemic member of the Tibetan Plateau fauna.

Fossil Primate Teeth as an Archive for High Resolution Ontogenic, Dietary and Palaeoclimate Record

ABSTRACT Rhythmic incremental growth of daily or longer duration is faithfully recorded in the tooth enamel of all the mammals including those of primates. Just a single well preserved fossil primate tooth can yield a variety of invaluable information, ranging from gestation period, age at weaning, age at death, prenatal and postnatal diet, ecology, water intake, and even body and brain size of an individual, that lived millions of years ago. Till a few years back fossil teeth of rare primates were physically sectioned to count these rhythmic growth lines for extracting ontogenic information such as, crown formation times, daily secretion rates, rhetzius line periodicity and enamel extension rates. Now all this is changing with the application of non-invasive X-Ray Synchroton micro-tomography. Further, laser ablation based stable carbon and oxygen isotope analyses of these growth layers are showing immense potential for yielding high resolution dietary, ecological and climate data, with minimal visible damage to the very rare fossil specimens.

The fauna of a Danian fossil Conservation Lagerstätten from the cold-water coral mound complex at Faxe, Denmark

Fossil cold-water coral mound ecosystems are rare in geological history. One of the best known examples are the Danian coral mounds of Faxe comprising a complex interplay between corals, bryozoans, and a diverse associated fauna. The Baunekule facies is a special type of weakly consolidated coral rudstone to floatstone found in the Faxe Formation. The facies has a rich fauna of 220 species that are extremely well-preserved due to an early diagenetic recrystallization of aragonite to calcite prior to dissolution and is regarded as a fossil conservation Lagerstätten. The fauna lived between dead and living coral fragments on the flank of a growing Dendrophyllia coral mound. The fauna is authocthonous and dominated by small gastropods, polychaete tubeworms, bivalves and brachiopods. The fauna from Baunekule facies are compared to other parts of the Faxe Formation which have experienced a significantly different diagenesis. More than 57% of the fauna are not described from others parts of the Faxe Fm. More than 80% of the studied species from the coral limestone are unknown from other parts of Danian localities worldwide. The study of the Baunekule facies compares well with data from modern living coral mounds of Lophelia with a low species richness of framebuilding corals and a high species richness of the associated highly specialised fauna that show a dominance of attached suspension feeders, mobile carnivores, and grazers. The small gastropods are apparently lacking on the modern mounds, probably related to the sampling methods in the deep ocean. In general, there is agreements between the ecology of the fossil and the modern cold-water coral ecosystems with evidence for similar environments from Danian to modern time. The fossil cold-water coral mounds probably acted as diversity hotspots in the outer shelf – slope settings in the Danian epicontinental sea. • Palaeoecological studies of 21,000 specimens from rare fossil cold-water coral mounds • Identifying a rich fauna of 220 well-preserved small species (mainly gastropods) • Preservation is due to an early diagenetic recrystallization of aragonite to calcite. • The ecology of the fossil and the modern cold-water coral ecosystems are comparable. • The fossil cold-water coral mounds acted as diversity hotspots on the Danian shelves.

Characteristic and paleoenvironment significance of microbially induced sedimentary structures (MISS) in terrestrial facies across P-T boundary in Western Henan Province, North China

AbstractWe report varied microbially induced sedimentary structures (MISS), and other sedimentary surface textures, from the Induan (Early Triassic) Sunjiagou Formation and Liujiagou Formation in the Xingyang, Dengfeng, Jiyuan and Yiyang areas, western Henan Province, North China. Microanalysis shows that these MISS are characterized by a U-shaped structure, thin clayey laminae, and discontinuous mica sheet that are arranged parallel to the bedding plane, as well as directionally oriented quartz grains floating in lamina, which are indicative of a biogenic origin. The MISS of the studied area were probably affected by four main factors, including the end-Permian mass extinction, the megamonsoon, the adapted sedimentary environment, and the sediment supply, and they possess significant stratigraphic correlation. Abundant microbial-related sedimentary structures from the study area indicate that continental ecosystems were severely devastated in the aftermath of the Permian-Triassic biocrisis. These sedimentary structure assemblages, including MISS, red beds, conglomerate layers, and calcareous concretions in the western Henan Province, show a specific, post-extinction continental ecosystem that was characterized by microflora dominance, monotonous and rare fossils, extreme hot climate, soil ecosystem devastation, and poor vegetation.

The type section of the Codell Sandstone

We formally assign, describe and interpret a principal reference section for the middle Turonian Codell Sandstone Member of the Carlile Shale near Codell, Kansas. This section, at the informally named Pumpjack Road, provides the thickest surface expression (9 m, ~30 ft) of the unit in Ellis County. The outcrop exposes features that typify the Codell throughout the southern Denver Basin and vicinity. At this reference section, the Codell conformably overlies the Blue Hill Shale Member of the Carlile Shale and is unconformably overlain by the Fort Hays Limestone Member of the Niobrara Formation or locally by a thin (<0.9 m, <3 ft) discontinuous mudstone known as the Antonino facies. The top contact of the Codell is slightly undulatory with possible compaction features or narrow (<30.5 m, <100 ft), low-relief (0.3-0.6 m, 1-2 ft) scours, all of which hint that the Codell is a depositional remnant, even at the type section. At Pumpjack Road, the Codell coarsens upward from a recessive-weathering argillaceous medium-grained siltstone with interbedded mudstone at its base to a more indurated cliff-forming muddy, highly bioturbated, very fine-grained sandstone at its top. The unit contains three informal gradational packages: a lower Codell of medium to coarse siltstone and mudstone, a middle Codell of muddy coarse siltstone, and an upper muddy Codell dominated by well-sorted very fine-grained sandstone. The largest grain fractions, all <120 mm in size, are mostly quartz (40-80%), potassium feldspar (7-12%), and albite (1-2%), with some chert (<15%), zircon, and other constituents such as abraded phosphatic skeletal debris. Rare fossil fish teeth and bones also occur. Detrital and authigenic clays make up 9 to 42% of the Codell at the reference section. Detrital illite and mixed layer illite/smectite are common, along with omnipresent kaolinite as grain coatings or cement. As is typical for the Codell, the sandstone at the type section has been pervasively bioturbated. Most primary structures and bedding are obscured, particularly toward the top of the unit where burrows are larger, deeper and more diverse than at its base. This bioturbation has created a textural inversion in which the larger silt and sand grains are very well sorted but are mixed with mud. Detrital zircons from the upper Codell are unusual in that they are mostly prismatic to acicular, euhedral, colorless, unpitted, and unabraded, and have a near-unimodal age peak centered at ~94 Ma. These characteristics suggest they were reworked mainly from Cenomanian bentonites; their ultimate source was likely from the Cordilleran orogenic belt to the west and northwest.

The wing venation of a new fossil species, reconstructed using geometric morphometrics, adds to the rare fossil record of Triassic Gondwanian Odonata

Probably the most common rock-imprint fossil-insect remain is an incomplete isolated wing. This pitfall has been traditionally addressed by manually reconstructing missing parts, which is not ideal to comprehend long-term evolutionary trends in the group, in particular for morphological diversity (i.e., disparity) approaches. Herein we describe a new Triassic relative of dragon- and damselflies (Odonata), Moltenophlebia lindae gen. et sp. nov., from the Molteno Formation (Karoo Basin, South Africa), on the basis of three incomplete, isolated wings. In order to provide a reconstruction of the complete wing venation of the species, we formalized and applied a repeatable method aiming at inferring the missing parts of a given specimen. It is based on homologous veins automatically identified thanks to a standardized color-coding. The dedicated script can be applied broadly to the fossil record of insect wings. The species is identified as a member of the Zygophlebiida, within the Triadophlebiomorpha. This discovery, therefore, represents the first ascertained occurrence of the latter group in Gondwana, an area where the fossil record of Odonata is depauperate.