Peter Van Roy
Ghent University, Geology, Department Member
- Ghent University, Department Geology and Soil Science, Department Memberadd
- Arthropods, Evolutionary Developmental Biology, Morphological evolution, Invertebrate Paleontology, Functional Morphology, Arthropoda, and 65 moreArthropod, Arthropod comparative morphology, Arthropod Evolution, Arthropod palaeobiology, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Fossil Arthropods, Invertebrate Zoology, Invertebrate Biology, Invertebrates, Invertebrate Palaeontology, Palaeontology, Paleontology, Paleobiology, Evolution and Phylogeny of Metazoan, Origins of Metazoans, Metazoan Origins, Metazoa, Ecdysozoa, Annelida, Annelid Taxonomy, Annelids, Morocco Ordovician Fezouata Lagerstatte, Fezouata Biota, Fezouata, Burgess Shale, Burgess Shale-type preservation, Konservat Lagerstatten, Taphonomy, Taphonomy and Paleoecology, Cambrian, Cambrian explosion, Cambrian and Precambrian, Cambrian Ecosystem, Cambrian Ecology, Ordovician, Ordovician Paleoecology, Paleoecology, Evolutionary Biology, Evolution, Paleontologia, History of Paleontology, Geology and Paleontology, Paleontología, Adhesives For Paleontological Conservation, Paleobotany; Paleontology; Paleoecology, Paleontological Illustration, Paleobiología, Palaeontology，Sedimentology，stratigraphy, Geology (Palaeontology and stratigraphy of Neoproterozoic and Early Cambrian), Palaeozoic stratigraphy and palaeontology, Marine Biology, Biology, Aquatic Invertebrates, Marine invertebrates, Invertebrate Taxonomy, Taxonomy of Marine Invertebrates, Invertebrate ecology, Invertebrados, Zoologia De Invertebrados, Evolutionary Ecology, Ordovician Trilobites, Upper Ordovician, Chelicerata, Chelicerate, and Fossil Cheliceratesedit
Cheloniellida is a rare but significant clade of artiopod euarthropods, and a major component of Vicissicaudata alongside aglaspidids. The first cheloniellid to be described was Triopus draboviensis, based on a single specimen from the... more
Cheloniellida is a rare but significant clade of artiopod euarthropods, and a major component of Vicissicaudata alongside aglaspidids. The first cheloniellid to be described was Triopus draboviensis, based on a single specimen from the Upper Ordovician Letná Formation in Bohemia. Because this specimen was believed to be missing its anterior, Triopus draboviensis has been the subject of considerable speculation regarding its affinities, with several authors combining various isolated cephalic shields with its trunk. Notwithstanding, Triopus draboviensis has eluded detailed restudy in the 150 years since its first description. Here we provide a redescription of the holotype and hitherto only known specimen of Triopus draboviensis, and describe a recently discovered second partial specimen as Triopus sp. It is shown that the holotype of Triopus draboviensis preserves the complete cephalic shield, while the trunk reveals a likely articulating device, which may represent an apomorphy for Cheloniellida. Further information on the trunk morphology provided by the new specimen has allowed a complete reconstruction of the dorsal exoskeleton of Triopus. An assessment is made of fossils previously suggested to represent the cephalic shield of Triopus draboviensis; while it is shown that none of those fossils can be attributed to Triopus, it is reaffirmed that Drabovaspis complexa likely does belong to Cheloniellida, making Drabovaspis the third cheloniellid genus known from the Letná Formation, after Triopus and Duslia. A revised diagnosis for Cheloniellida is provided, and the recently described problematic euarthropod Parioscorpio venator from the Silurian of Wisconsin is firmly rejected from this clade.
Research Interests:
The extensive, predominantly siliciclastic deposits of the Upper Ordovician of the Tafilalt have long been the subject of scientific investigation. In the past 25 years, intensified collecting for commercial purposes has resulted in the... more
The extensive, predominantly siliciclastic deposits of the Upper Ordovician of the Tafilalt have long been the subject of scientific investigation. In the past 25 years, intensified collecting for commercial purposes has resulted in the discovery of several exceptionally-preserved faunas (Konservat-Lagerstätten) in the Tafilalt region, preserving a range of non-biomineralized and soft-bodied organisms. The preservation of these fossils in the coarse clastic sediments of the Tafilalt is surprising, and in the case of soft-bodied organisms, remarkably similar to the preservational mode of typical Ediacaran biotas. These relatively recent discoveries have increased the scientific significance of the Tafilalt Biota, providing an unparalleled insight into the composition and temporal evolution of the shallow, open-marine ecosystems and their denizens during the later stages of the Great Ordovician Biodiversification Event. At least nine different phyla, in addition to several soft-bodied problematica are represented in the Tafilalt. While the highly diverse and remarkably well-preserved echinoderm and euarthropod faunas are most emblematic for the Tafilalt Biota, further studies have revealed a relatively high diversity of molluscs and brachiopods. Among soft-bodied fossils, the problematic paropsonemid eldonids are iconic for the Tafilalt and stand out both through their abundance, and their wide temporal and geographical range throughout the area.
Research Interests:
The Anti-Atlas contains a thick, volcanic-free Ordovician succession that originally deposited in a passive-margin basin. Three main sedimentary packages are bounded by major unconformities: (i) the Tremadocian Floian Lower Fezouata and... more
The Anti-Atlas contains a thick, volcanic-free Ordovician succession that originally deposited in a passive-margin basin. Three main sedimentary packages are bounded by major unconformities: (i) the Tremadocian Floian Lower Fezouata and Upper Fezouata formations, which unconformably overlie a palaeorelief of Cambrian rifting volcanosedimentary complexes, and are subsequently topped by a Dapingian paraconformable gap; (ii) the Darriwilian–Katian Tachilla Formation and First Bani and Ktaoua groups, the latter unconformably overlain by a Hirnantian glaciogenic succession; and (iii) the Second Bani Group, which subsequently infilled the former glaciogenic palaeorelief. Due to the scarcity of carbonate interbeds for etching analyses, leading to rare references of conodonts, the global Ordovician chart is interpolated on the basis of microphytoplancton (acritarchs and chitinozoans), regional graptolites and brachiopods. The Ordovician counter-clockwise rotation of Gondwana led its Moroccan margin from mid- to high-latitude positions, leading to the onset of a siliciclastic, wave- and storm-dominated platform. Flooding surfaces are marked by shelly silty carbonate interbeds that reflect the episodic development of echinoderm–bryozoan meadows during Katian times; in areas protected from siliciclastic input, they reached massive and bedded bioaccumulations (Khabt-el-Hajar Formation). The Hirnantian glaciation controlled the incision of numerous tunnel channels, infilled with both alluvial to fluvial sediments and glaciomarine diamictites. The Hirnantian palaeorelief was definitively sealed during Silurian times.
Research Interests:
Thylacocephala is a clade of marine bivalved euarthropods generally considered to belong to Eucrustacea, although their affinities within this group remain unsettled. Detailed thylacocephalan anatomy and tagmosis is poorly known, and the... more
Thylacocephala is a clade of marine bivalved euarthropods generally considered to belong to Eucrustacea, although their affinities within this group remain unsettled. Detailed thylacocephalan anatomy and tagmosis is poorly known, and the majority of taxa have been described based only on the valves of the carapace. While some thylacocephalans are considered to have been fully nektic, others probably had a nekto-benthic mode of life. The group makes its last appearance in the Upper Cretaceous of Lebanon, while the previously oldest definite record is from the Silurian of Wisconsin, USA. This paper describes two new thylacocephalans, Pseudoprotozoea irenae gen. et sp. nov. and Bohemiacaris libori gen. et sp. nov. from the Sandbian (Upper Ordovician) Letná Formation of Bohemia (Czech Republic). Apart from the carapaces, both fossils preserve some evidence of the appendages. Remarkably, even though the newly described taxa represent the oldest unequivocal thylacocephalans, their carapaces display several characters most similar to those of Mesozoic groups. Whether these similarities reflect true close relationships and Ordovician origins for these groups or are only the result of convergent evolution is uncertain. Regardless, the new finds show that ecological differentiation between fully nektic and nektobenthic lifestyles was probably achieved early in the evolution of Thylacocephala.
Research Interests: Paleobiology, Invertebrate Biology, Czech, Crustacea, Evolution, and 15 moreInvertebrate Zoology, Palaeobiology, Invertebrate Paleontology, Arthropoda, Ordovician, Palaeozoic, Arthropod, Paleozoic, Invertebrate Palaeontology, Metazoa, Thylacocephala, Letná, concavicarida, conchyliocarida, and Sandbian
Euarthropods have a tough exoskeleton that provides crucial protection from predation and parasitism. However, this is restrictive to growth and must be periodically moulted. The moulting sequence is well-known from extant arthropods,... more
Euarthropods have a tough exoskeleton that provides crucial protection from predation and parasitism. However, this is restrictive to growth and must be periodically moulted. The moulting sequence is well-known from extant arthropods, consisting of: (i) the long inter-moult stage, in which no changes occur to the hardened exoskeleton; (ii) the pre-moult stage where the old exoskeleton is detached and the new one secreted; (iii) exuviation, when the old exoskeleton is moulted; and (iv) the post-moult stage during which the new exoskeleton starts as soft, thin, and partially compressed and gradually hardens to the robust exoskeleton of the inter-moult stage. Trilobite fossils typically consist of inter-moult carcasses or moulted exuviae, but specimens preserving the post-moult stage are rare. Here we describe nine specimens assigned to Symphysurus ebbestadi representing the first group of contemporaneous fossils collected that preserve all key stages of the moulting process in one taxon, including the post-moult stage. They were collected from a single lens in the Tremadocian part of the Fezouata Shale Formation, Morocco. Based on cephalic displacement and comparison to other trilobite moults, one specimen appears to represent a moulted exoskeleton. Four specimens are typical inter-moult carcasses. Four others are wrinkled and flattened, with thin exoskeletons compared to inter-moult specimens, and are considered post-moult individuals. These S. ebbestadi specimens illuminate the preservation and morphology of the post-moulting stage, characterised by strong anterior-posterior exoskeleton wrinkling, as well as overall body flattening and reduced visibility of thoracic articulations. Being found in the same lens, these specimens likely represent the first preserved in-the-act mass moulting event. The displayed sequence of moulting suggests the moulting process in trilobites was comparable to modern arthropods, and conserved within euarthropod evolutionary history.
Research Interests:
The Weeks Formation in Utah is the youngest (c. 499 Ma) and least studied Cambrian Lagerstätte of the western USA. It preserves a diverse, exceptionally preserved fauna that inhabited a relatively deep water environment at the offshore... more
The Weeks Formation in Utah is the youngest (c. 499 Ma) and least studied Cambrian Lagerstätte of the western USA. It preserves a diverse, exceptionally preserved fauna that inhabited a relatively deep water environment at the offshore margin of a carbonate platform, resembling the setting of the underlying Wheeler and Marjum formations. However, the Weeks fauna differs significantly in composition from the other remarkable biotas of the Cambrian Series 3 of Utah, suggesting a significant Guzhangian faunal restructuring. This bioevent is regarded as the onset of a transitional episode in the history of life, separating the two primary diversifications of the Early Paleozoic. The Weeks fossils have been strongly affected by late diagenetic processes, but some specimens still preserve exquisite anatomical details. Supplementary material: a supplementary text (material and methods), four supplementary tables (compositions of the lower and upper Weeks faunas, structure of the upper Weeks fauna, and results of the similarity analyses), and a supplementary data file (generic presence/absence matrix) are available at https://doi.
Research Interests: Evolutionary Biology, Marine Biology, Paleobiology, Zoology, Paleontology, and 43 moreBiology, Evolution, Invertebrate Zoology, Palaeontology, Palaeobiology, Invertebrate Paleontology, Biological Sciences, Arthropoda, Palaeontology，Sedimentology，stratigraphy, Cambrian, Ordovician, Biologia, Cambrian Ecosystem, Cambrian-Devonian trilobites, Arthropod, Paleontologia, Chengjiang Lagerstatte, Morocco Ordovician Fezouata Lagerstatte, General Zoology, Burgess Shale, Cambrian explosion, Arthropods, Invertebrate Palaeontology, Geology and Paleontology, Largerstatte, Fossils Cambrian to Devonian.fossil chelicerates,eurypterid fossils especially of N.E. North America, Fezouata, Lagerstätte, Arthropod palaeobiology, Cambrian and Precambrian, Cambrian Fossils, Paleontología, Chengjiang biota, Lagerstatten, Cambrian Trilobite, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Fossil Arthropods, Ordovician Paleoecology, Weeks formation, Cambrian Trilobites, Konservat Lagerstatten, Fezouata Biota, and Cambrian Ecology
Exceptionally preserved fossils provide crucial insights into extinct body plans and organismal evolution. Molluscs, one of the most disparate animal phyla, radiated rapidly during the early Cambrian period (approximately 535–520 million... more
Exceptionally preserved fossils provide crucial insights into extinct body plans and organismal evolution. Molluscs, one of the most disparate animal phyla, radiated rapidly during the early Cambrian period (approximately 535–520 million years ago (Ma)). The problematic fossil taxa Halkieria and Orthrozanclus (grouped in Sachitida) have been assigned variously to stem-group annelids, brachiopods , stem-group molluscs or stem-group aculiferans (Polyplacophora and Aplacophora), but their affinities have remained controversial owing to a lack of preserved diagnostic characters. Here we describe a new early sachitid, Calvapilosa kroegeri gen. et sp. nov. from the Fezouata biota of Morocco (Early Ordovician epoch, around 478 Ma). The new taxon is characterized by the presence of a single large anterior shell plate and polystichous radula bearing a median tooth and several lateral and uncinal teeth in more than 125 rows. Its flattened body is covered by hollow spinose sclerites, and a smooth, ventral girdle flanks an extensive mantle cavity. Phylogenetic analyses resolve C. kroegeri as a stem-group aculiferan together with other single-plated forms such as Maikhanella (Siphogonuchites) and Orthrozanclus; Halkieria is recovered closer to the aculiferan crown. These genera document the stepwise evolution of the aculiferan body plan from forms with a single, almost conchiferan-like shell through two-plated taxa such as Halkieria, to the eight-plated crown-group aculiferans. C. kroegeri therefore provides key evidence concerning the long debate about the crown molluscan affinities of sachitids. This new discovery strongly suggests that the possession of only a single calcareous shell plate and the presence of unmineralised sclerites are plesiomorphic (an ancestral trait) for the molluscan crown.
Research Interests: Evolutionary Biology, Paleobiology, Paleontology, Invertebrate Biology, Invertebrates, and 45 moreEvolution, Molluscan Biology, Invertebrate Zoology, Palaeontology, Palaeobiology, Mollusks, Invertebrate Paleontology, Mollusc Taxonomy, Aquatic Invertebrates, Palaeobiology, Mass Extinctions, Phylogeny, Palaeontology，Sedimentology，stratigraphy, Cambrian, Ordovician, Cambrian Ecosystem, Invertebrados, Mollusc, Paleontologia, Mollusca, Molluscan paleontology and biostratigraphy, Morocco Ordovician Fezouata Lagerstatte, Burgess Shale-type preservation, Burgess Shale, Cambrian explosion, Marine invertebrates, Molluscs, Invertebrate Palaeontology, Geology and Paleontology, Aculifera, Fezouata, Molluscan taxonomy and nomenclature, Cambrian and Precambrian, Paleobiología, Cambrian Fossils, Paleontología, Invertebrate Taxonomy, Palaeobiodiversity, Ordovician Paleoecology, Taxonomy of Marine Invertebrates, Fezouata Biota, Cambrian Ecology, Zoologia De Invertebrados, Marine Molluscs, Upper Fezouata Formation, Mollusk Biodiversity, and Mollusk Ecology
Exceptionally preserved fossils from the Palaeozoic era provide crucial insights into arthropod evolution, with recent discoveries bringing phylogeny and character homology into sharp focus. Integral to such studies are anomalocaridids, a... more
Exceptionally preserved fossils from the Palaeozoic era provide crucial insights into arthropod evolution, with recent discoveries bringing phylogeny and character homology into sharp focus. Integral to such studies are anomalocaridids, a clade of stem arthropods whose remarkable morphology illuminates early arthropod relationships and Cambrian ecology. Although recent work has focused on the anomalocaridid head, the nature of their trunk has been debated widely.Here we describe new anomalocaridid specimens from the Early Ordovician Fezouata Biota of Morocco, which not only show well-preserved head appendages providing key ecological data, but also elucidate the nature of anomalocaridid trunk flaps, resolving their homology with arthropod trunk limbs. The new material shows that each trunk segment bears a separate dorsal and ventral pair of flaps, with a series of setal blades attached at the base of the dorsal flaps. Comparisons with other stem lineage arthropods indicate that anomalocaridid ventral flaps are homologous with lobopodous walking limbs and the endopod of the euarthropod biramous limb, whereas the dorsal flaps and associated setal blades are homologous with the flaps of gilled lobopodians (for example, Kerygmachela kierkegaardi, Pambdelurion whittingtoni) and exites of the ‘Cambrian biramous limb’. This evidence shows that anomalocaridids represent a stage before the fusion of exite and endopod into the ‘Cambrian biramous limb’, confirming their basal placement in the euarthropod stem, rather than in the arthropod crown or with cycloneuralian worms. Unlike other anomalocaridids, the Fezouata taxon combines head appendages convergently adapted for filter-feeding with an unprecedented body length exceeding 2m, indicating a new direction in the feeding ecology of the clade. The evolution of giant filter-feeding anomalocaridids may reflect the establishment of highly developed planktic ecosystems during the Great Ordovician Biodiversification Event.
Research Interests: Paleobiology, Paleontology, Functional Morphology, Invertebrate Biology, Invertebrates, and 40 morePalaeoecology, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Aquatic Invertebrates, Gigantism, Arthropoda, Cambrian, Ordovician, Cambrian Ecosystem, Invertebrados, Arthropod, Anomalocaridids, Morocco Ordovician Fezouata Lagerstatte, Cambrian explosion, Marine invertebrates, Arthropods, Invertebrate Palaeontology, Evolution and Phylogeny of Metazoan, Anomalocaris, Arthropod palaeobiology, Exceptional fossilization, Cambrian and Precambrian, Invertebrate ecology, Filter feeding, Invertebrate Taxonomy, Arthropod comparative morphology, Metazoan Origins, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Metazoa, Fossil Arthropods, Ordovician Paleoecology, Exceptional Fossil Preservation, Taxonomy of Marine Invertebrates, Konservat Lagerstatten, Origins of Metazoans, Zoologia De Invertebrados, Great Ordovician Biodiversification Event, and Suspension-Feeding
Anomalocaridids, giant lightly sclerotized invertebrate predators, occur in a number of exceptionally preserved early and middle Cambrian (542–501 million years ago) biotas and have come to symbolize the unfamiliar morphologies displayed... more
Anomalocaridids, giant lightly sclerotized invertebrate predators,
occur in a number of exceptionally preserved early and middle
Cambrian (542–501 million years ago) biotas and have come to
symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type. They are characterized by a pair ofanterior, segmented appendages, a circlet of plates around the mouth, and an elongate segmented trunk lacking true tergites with a pair of flexible lateral lobes per segment. Disarticulated body parts, such as the anterior appendages and oral circlet, had been assigned to a range of taxonomic groups—but the discovery of complete specimens from the middle Cambrian Burgess Shale showed that these disparate elements all belong to a single kind of animal. Phylogenetic analyses support a position of anomalocaridids in the arthropod stem, as a sister group to the euarthropods. The anomalocaridids were the largest animals in Cambrian communities. The youngest unequivocal examples occur in the middle Cambrian Marjum Formation of Utah but an arthropod retaining some anomalocaridid characteristics is present in the Devonian of Germany. Here we report the post-Cambrian occurrence of anomalocaridids, from the Early Ordovician (488–472 million years ago) Fezouata Biota in southeastern Morocco, including specimens larger than any in Cambrian biotas. These giant animals were an important element of some marine communities for about 30 million years longer than previously realized. The Moroccan specimens confirm the presence of a dorsal array of flexible blades attached to a transverse rachis on the trunk segments; these blades probably functioned as gills.
occur in a number of exceptionally preserved early and middle
Cambrian (542–501 million years ago) biotas and have come to
symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type. They are characterized by a pair ofanterior, segmented appendages, a circlet of plates around the mouth, and an elongate segmented trunk lacking true tergites with a pair of flexible lateral lobes per segment. Disarticulated body parts, such as the anterior appendages and oral circlet, had been assigned to a range of taxonomic groups—but the discovery of complete specimens from the middle Cambrian Burgess Shale showed that these disparate elements all belong to a single kind of animal. Phylogenetic analyses support a position of anomalocaridids in the arthropod stem, as a sister group to the euarthropods. The anomalocaridids were the largest animals in Cambrian communities. The youngest unequivocal examples occur in the middle Cambrian Marjum Formation of Utah but an arthropod retaining some anomalocaridid characteristics is present in the Devonian of Germany. Here we report the post-Cambrian occurrence of anomalocaridids, from the Early Ordovician (488–472 million years ago) Fezouata Biota in southeastern Morocco, including specimens larger than any in Cambrian biotas. These giant animals were an important element of some marine communities for about 30 million years longer than previously realized. The Moroccan specimens confirm the presence of a dorsal array of flexible blades attached to a transverse rachis on the trunk segments; these blades probably functioned as gills.
Research Interests: Paleobiology, Paleontology, Invertebrate Biology, Invertebrates, Invertebrate Zoology, and 27 morePalaeontology, Invertebrate Paleontology, Aquatic Invertebrates, Arthropoda, Cambrian, Ordovician, Cambrian Ecosystem, Arthropod, Anomalocaridids, Morocco Ordovician Fezouata Lagerstatte, Cambrian explosion, Marine invertebrates, Arthropods, Invertebrate Palaeontology, Anomalocaris, Arthropod palaeobiology, Cambrian and Precambrian, Cambrian Fossils, Invertebrate Taxonomy, Arthropod comparative morphology, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Fossil Arthropods, Ordovician Paleoecology, Taxonomy of Marine Invertebrates, Cambrian Ecology, and Great Ordovician Biodiversification Event
The renowned soft-bodied faunas of the Cambrian period, which include the Burgess Shale, disappear from the fossil record in the late Middle Cambrian, after which the Palaeozoic fauna dominates. The disappearance of faunas of Burgess... more
The renowned soft-bodied faunas of the Cambrian period, which
include the Burgess Shale, disappear from the fossil record in the late Middle Cambrian, after which the Palaeozoic fauna dominates. The disappearance of faunas of Burgess Shale type curtails the stratigraphic record of a number of iconic Cambrian taxa. One possible explanation for this loss is a major extinction, but more probably it reflects the absence of preservation of similar softbodied faunas in later periods. Here we report the discovery of numerous diverse soft-bodied assemblages in the Lower and
Upper Fezouata Formations (Lower Ordovician) of Morocco,
which include a range of remarkable stem-group morphologies
normally considered characteristic of the Cambrian. It is clear that biotas of Burgess Shale type persisted after the Cambrian and are preserved where suitable facies occur. The Fezouata biota provides a link between the Burgess Shale communities and the early stages of the Great Ordovician Biodiversification Event.
include the Burgess Shale, disappear from the fossil record in the late Middle Cambrian, after which the Palaeozoic fauna dominates. The disappearance of faunas of Burgess Shale type curtails the stratigraphic record of a number of iconic Cambrian taxa. One possible explanation for this loss is a major extinction, but more probably it reflects the absence of preservation of similar softbodied faunas in later periods. Here we report the discovery of numerous diverse soft-bodied assemblages in the Lower and
Upper Fezouata Formations (Lower Ordovician) of Morocco,
which include a range of remarkable stem-group morphologies
normally considered characteristic of the Cambrian. It is clear that biotas of Burgess Shale type persisted after the Cambrian and are preserved where suitable facies occur. The Fezouata biota provides a link between the Burgess Shale communities and the early stages of the Great Ordovician Biodiversification Event.
Research Interests: Paleobiology, Paleontology, Invertebrate Biology, Invertebrates, Palaeoecology, and 27 moreInvertebrate Zoology, Palaeontology, Invertebrate Paleontology, Paleozoic communities, Aquatic Invertebrates, Cambrian, Ordovician, Cambrian Ecosystem, Palaeozoic, Palaeozoic stratigraphy and palaeontology, Paleozoic, Morocco Ordovician Fezouata Lagerstatte, Burgess Shale-type preservation, Burgess Shale, Cambrian explosion, Marine invertebrates, Evolution and Phylogeny of Metazoan, Exceptional fossilization, Cambrian and Precambrian, Metazoan Origins, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Metazoa, Ordovician Paleoecology, Exceptional Fossil Preservation, Konservat Lagerstatten, Origins of Metazoans, and Great Ordovician Biodiversification Event
The systematic affinities of several Palaeozoic skeletal taxa were only resolved when their soft-tissue morphology was revealed by the discovery of exceptionally preserved specimens. The conodonts provide a classic example, their... more
The systematic affinities of several Palaeozoic skeletal taxa were only resolved when their soft-tissue morphology was revealed by the discovery of exceptionally preserved specimens. The conodonts provide a classic example, their tooth-like elements having been assigned to various invertebrate and vertebrate groups for more than 125 years until the discovery of their soft tissues revealed them to be crown-group vertebrates. Machaeridians, which are virtually ubiquitous as shell plates in benthic marine shelly assemblages ranging from Early Ordovician (Late Tremadoc) to Carboniferous, have proved no less enigmatic. The Machaeridia comprise three distinct families of worm-like animals, united by the possession of a dorsal skeleton of calcite plates that is rarely found articulated. Since they were first described 150 years ago machaeridians have been allied with barnacles, echinoderms, molluscs or annelids. Here we describe a new machaeridian with preserved soft parts, including parapodia and chaetae, from the Upper Tremadoc of Morocco, demonstrating the annelid affinity of the group. This discovery shows that a lineage of annelids evolved a dorsal skeleton of calcareous plates early in their history; it also resolves the affinities of a group of problematic Palaeozoic invertebrates previously known only from isolated elements and occasional skeletal assemblages.
Research Interests: Paleobiology, Zoology, Paleontology, Functional Morphology, Invertebrate Biology, and 23 moreInvertebrates, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Aquatic Invertebrates, Annelida, Ordovician, Invertebrados, Morocco Ordovician Fezouata Lagerstatte, Marine invertebrates, Annelids, Invertebrate Palaeontology, Fezouata, Exceptional fossilization, Convergent Evolution, Invertebrate Taxonomy, Annelid Taxonomy, Exceptional Fossil Preservation, Taxonomy of Marine Invertebrates, Konservat Lagerstatten, Fezouata Biota, Zoologia De Invertebrados, and Great Ordovician Biodiversification Event
The discovery of the Fezouata biota in the latest Tremadocian of southeastern Morocco has significantly changed our understanding of the early Phanerozoic radiation. The shelly fossil record shows a well-recognized pattern of... more
The discovery of the Fezouata biota in the latest Tremadocian of southeastern Morocco has significantly changed
our understanding of the early Phanerozoic radiation. The shelly fossil record shows a well-recognized pattern of macroevolutionary
stasis between the Cambrian Explosion and the Great Ordovician Biodiversification Event, but the rich soft-bodied
Fezouata biota paints a different evolutionary picture. The Fezouata assemblage includes a considerable component of
Cambrian holdovers alongside a surprising number of crown group taxa previously unknown to have evolved by the Early
Ordovician. Study of the Fezouata biota is in its early stages, and future discoveries will continue to enrich our view of the
dynamics of the early Phanerozoic radiation and of the nature of the fossil record.
our understanding of the early Phanerozoic radiation. The shelly fossil record shows a well-recognized pattern of macroevolutionary
stasis between the Cambrian Explosion and the Great Ordovician Biodiversification Event, but the rich soft-bodied
Fezouata biota paints a different evolutionary picture. The Fezouata assemblage includes a considerable component of
Cambrian holdovers alongside a surprising number of crown group taxa previously unknown to have evolved by the Early
Ordovician. Study of the Fezouata biota is in its early stages, and future discoveries will continue to enrich our view of the
dynamics of the early Phanerozoic radiation and of the nature of the fossil record.
Research Interests: Paleobiology, Paleontology, Invertebrate Paleontology, Paleozoic communities, Arthropoda, and 22 moreCambrian, Ordovician, Cambrian Ecosystem, Palaeozoic, Arthropod, Palaeozoic stratigraphy and palaeontology, Paleozoic, Morocco Ordovician Fezouata Lagerstatte, Cambrian explosion, Arthropods, Fezouata, Evolution and Phylogeny of Metazoan, Arthropod palaeobiology, Cambrian and Precambrian, Arthropod comparative morphology, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Ordovician Paleoecology, Exceptional Fossil Preservation, Konservat Lagerstatten, Fezouata Biota, and Great Ordovician Biodiversification Event
Palaeoscolecids are long cylindrical annulated vermiform ecdysozoans with an eversible proboscis comparable with that of priapulids. Their most conspicious external feature are aligned knob-like sclerites of assumed primary phosphatic... more
Palaeoscolecids are long cylindrical annulated vermiform ecdysozoans with an eversible proboscis comparable with that of priapulids. Their most conspicious external feature are aligned knob-like sclerites of assumed primary phosphatic origin associated to the annulations of their molting cuticle. Recent cladistic analyses indicate that palaeoscolecids probably belong to the stem lineage Priapulida. Their fossil record ranges from the early Cambrian to the late Silurian, but only isolated sclerites or small clusters of sclerites are usually found in sediments as SSF or SCF. By contrast, complete animals are relatively rare except in some Early Cambrian Lagerstätten such as in Chengjiang. Here are reported virtually complete specimens from several localities of Utah and Morocco which give important information on the anatomy, ecology and distribution of Palaeoscolecida through the Cambrian-Ordovician transition. Two specimens were recovered from the Issafen Formation (Cambrian Series ...
The Lower Ordovician Fezouata Konservat-Lagerstätte from southern Morocco has been one of the major palaeontological discoveries of the last decade. It provides a unique insight into one of the most critical periods in the evolution of... more
The Lower Ordovician Fezouata Konservat-Lagerstätte from southern Morocco has been one of the major
palaeontological discoveries of the last decade. It provides a unique insight into one of the most critical periods
in the evolution of marine life: the Cambrian–Ordovician transition. However, its potential for deciphering key
trends in animal diversification was hitherto largely limited by major uncertainties concerning its stratigraphic
position, age and environmental setting. Based on extensive fieldwork, fossil evidence, and facies recognition,
our study provides clarification on these three crucial issues. Exceptional preservation is limited to two intervals
within the Fezouata Shale. Graptolites indicate a late Tremadocian age for the Fezouata Konservat-Lagerstätte as
awhole,which is supported by biostratigraphical evidence provided by acritarchs. Sedimentological features and
reconstructed patterns of relative sea-level changes indicate relatively shallow-water environmental conditions,
under distal storm influence, in an offshore to lower shoreface siliciclastic ramp setting. The Fezouata Biota represents
a unique and exceptional window into the palaeobiodiversity in open-marine conditions, thus contrastingwith
the otherOrdovician Konservat-Lagerstätten presently known. In our analyses of this newset of data,we
pave the way for accurate temporal, faunal and environmental comparisons with other Lower Palaeozoic
Konservat-Lagerstätten, and unlock the full potential of the Fezouata Biota to better understand the processes
and scenarios of early animal radiations.
palaeontological discoveries of the last decade. It provides a unique insight into one of the most critical periods
in the evolution of marine life: the Cambrian–Ordovician transition. However, its potential for deciphering key
trends in animal diversification was hitherto largely limited by major uncertainties concerning its stratigraphic
position, age and environmental setting. Based on extensive fieldwork, fossil evidence, and facies recognition,
our study provides clarification on these three crucial issues. Exceptional preservation is limited to two intervals
within the Fezouata Shale. Graptolites indicate a late Tremadocian age for the Fezouata Konservat-Lagerstätte as
awhole,which is supported by biostratigraphical evidence provided by acritarchs. Sedimentological features and
reconstructed patterns of relative sea-level changes indicate relatively shallow-water environmental conditions,
under distal storm influence, in an offshore to lower shoreface siliciclastic ramp setting. The Fezouata Biota represents
a unique and exceptional window into the palaeobiodiversity in open-marine conditions, thus contrastingwith
the otherOrdovician Konservat-Lagerstätten presently known. In our analyses of this newset of data,we
pave the way for accurate temporal, faunal and environmental comparisons with other Lower Palaeozoic
Konservat-Lagerstätten, and unlock the full potential of the Fezouata Biota to better understand the processes
and scenarios of early animal radiations.
Research Interests:
The recently discovered Fezouata Biota, from the Early Ordovician (late Tremadocian to late Floian) of Morocco, preserves a diverse soft-bodied fauna. While preservation is mostly of Burgess Shale-type, giant anomalocaridids also occur in... more
The recently discovered Fezouata Biota, from the Early Ordovician (late Tremadocian to late Floian) of Morocco, preserves a diverse soft-bodied fauna. While preservation is mostly of Burgess Shale-type, giant anomalocaridids also occur in siliceous concretions. Petrographic and geochemical analyses of these concretions reveal their growth history and the circumstances that led to the fossilization of nonbiomineralized anatomy within them. The large (.1 m) concretions are homogeneous in composition and geochemical characteristics, suggesting rapid, pervasive growth of mineral frameworks during decay of the large animals at, or near, the sediment-water interface. Concretions are comprised of ultrafine-grained (2–20 mm) authigenic quartz, Fe chlorite, and calcite, a composition unlike other described marine concretions. Abundant pyrite, now represented by oxide pseudomorphs, grew adjacent to the anomalocaridid carcasses, but rarely within the matrix of the concretions. This distribution indicates that sulfate reduction around the carcasses was vigorous within otherwise organic-poor sediments resulting in the establishment of prominent chemical gradients around the giant anomalocaridids that led to early precipitation of mineral overgrowth around nonbiomineralized tissues. Rapid precipitation of intergrown silica and Fe chlorite required an abundant source of silica, iron, and aluminum. These ions were likely derived from dissolution of volcanic ash in the sediments. Limited intergrown calcite (d 13 C avg. 212.2%o, n 5 23) precipitated from bicarbonate that was generated largely by sulfate reduction of organic tissues of the carcasses. Whereas Burgess Shale-type preservation of fossils in the Fezouata biota required suppression of degradation, exceptional preservation of anomalocaridids within the siliceous concretions resulted from extensive microbial decomposition of a large volume of organic tissues. Rapid mineralization was facilitated by localization of microbial activity around the large carcasses and must have required an unusually reactive sediment composition.
Research Interests:
A new aglaspidid euarthropod with a six-segmented trunk from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco Abstract – A new euarthropod with an uncommon morphology, Brachyaglaspis singularis gen. et sp. nov., is described... more
A new aglaspidid euarthropod with a six-segmented trunk from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco Abstract – A new euarthropod with an uncommon morphology, Brachyaglaspis singularis gen. et sp. nov., is described from the Early Ordovician (middle Floian) Fezouata biota of Morocco. The presence of a pair of postventral plates, widely attached to each other and located under the posterior-most trunk tergite and the base of the tailspine, indicates a phylogenetic relationship with the enigmatic group Aglaspidida. The overall morphology of Brachyaglaspis most closely resembles that of the 'Ordovician-type' aglaspidids, more specifically the late Cambrian – Early Ordovician genus Tremaglaspis. However, the presence of a prominent cephalon and only six trunk tergites in the new genus deviates from the organization of all other known aglaspidid species, notably extending the known range of morphological disparity of the group. A taxonomic revision of this euarthropod group indicates that the most accurate name and authorship combination correspond to Aglaspidida Walcott, 1912.
Research Interests: Paleobiology, Paleontology, Invertebrate Biology, Invertebrates, Invertebrate Zoology, and 24 morePalaeontology, Invertebrate Paleontology, Aquatic Invertebrates, Arthropoda, Ordovician, Invertebrados, Arthropod, Morocco Ordovician Fezouata Lagerstatte, Marine invertebrates, Arthropods, Invertebrate Palaeontology, Fezouata, Arthropod palaeobiology, Aglaspidida, Invertebrate Taxonomy, Arthropod comparative morphology, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Fossil Arthropods, Taxonomy of Marine Invertebrates, Fezouata Biota, Arthropoda. Aglaspidida, Aglaspis, and Great Ordovician Biodiversification Event
A new aglaspidid arthropod, Chlupacaris dubia gen. et sp. nov., is described from the Pusgillian (lower Ashgill, Upper Ordovician) Upper Tiouririne Formation near Erfoud, southeastern Morocco. Although disarticulated, careful documenting... more
A new aglaspidid arthropod, Chlupacaris dubia gen. et sp. nov., is described from the Pusgillian (lower Ashgill, Upper Ordovician) Upper Tiouririne Formation near Erfoud, southeastern Morocco. Although disarticulated, careful documenting of the tergites allows a reconstruction of the exoskeleton to be made. Although somewhat trilobite-like in appearance, the lack of facial sutures, a well-defined axis with articulating half-rings and a pygidium clearly prove Chlupacaris gen. nov. is not a trilobite. An interesting feature is the presence of a hypostome in this non-trilobite arthropod. In contrast to other aglaspidids usually considered to be carnivorous, a filter-feeding mode of life is proposed for Chlupacaris gen. nov., based on the strongly vaulted cephalon, subvertical orientation of the hypostome and less strongly vaulted trunk. Chlupacaris gen. nov. is probably most closely related to the atypical aglaspidid Tremaglaspis unite from the Tremadoc (Lower Ordovician) of the U.K., but it can also be tentatively linked to the problematic Lower Cambrian arthropods Kodymirus vagans and Kockurus grandis from the Czech Republic. The relevance and validity of previous definitions and of possibly significant characters used for identifying aglaspidids are evaluated, and as a result, a new combination of characters diagnosing Aglaspidida is proposed. Contrary to previous reports, it is suggested that aglaspidids are probably more closely related to trilobites than they are to chelicerates. This notion may be supported by the shared possession of a mineralised cuticle, a possibly similar number of cephalic appendages, and the presence of a hypostome in some forms, although this last character may alternatively be homoplastic.
Research Interests: Evolutionary Biology, Marine Biology, Paleontology, Invertebrate Biology, Invertebrates, and 22 moreBiology, Invertebrate Zoology, Invertebrate Paleontology, Aquatic Invertebrates, Arthropoda, Ordovician, Arthropod, Paleontologia, Paleobotany; Paleontology; Paleoecology, Marine invertebrates, Arthropods, Geology and Paleontology, Arthropod palaeobiology, Aglaspidida, Paleontología, Invertebrate Taxonomy, Arthropod comparative morphology, Arthropod Evolution, Fossil Arthropods, Konservat Lagerstatten, Arthropoda. Aglaspidida, and Aglaspis
Exceptionally preserved fossils yield crucial information about the evolution of Life on Earth. The Fezouata Biota from the Lower Ordovician of Morocco is a Konservat-Lagerstätte of major importance, and it is today considered as an... more
Exceptionally preserved fossils yield crucial information about the evolution of Life on Earth. The Fezouata Biota from the Lower Ordovician of Morocco is a Konservat-Lagerstätte of major importance, and it is today considered as an 'Ordovician Burgess Shale.' This biota was discovered only some 15 years ago, but geological studies of the area date back to the beginning of the 20th century. Pioneering geological investigations lead to the discovery of Ordovician strata in the Anti-Atlas (1929) and ultimately resulted in their formal subdivision into four main strat-igraphic units (1942). In the Agdz area, the presence of fossiliferous Tremadocian (Lower Ordovician) strata was suspected as early as 1939, but only definitively confirmed in 1955. In the 1960s–1990s, Jacques Destombes provided the first detailed biostratigraphic framework for the Lower Ordovician of the Anti-Atlas, and collected thousands of fossils that were subsequently described in a series of monographs. In the early 2000s, exceptionally preserved fossils were discovered in the Fezouata Shale (Tremadocian–late Floian) in the central Anti-Atlas by Mohamed 'Ou Saïd' Ben Moula. This biota, now known as the Fezouata Biota, is of utmost importance, for it demonstrates the extent in the fossil record of non-biomineralising animals typical of the 'Cambrian Explosion' into the Ordovician, during the 'Great Ordovician Biodiversification.' Although most components are still in need of formal descriptions, a fairly good picture of the composition and organisation of this biota, and how it contributes to our understanding of the early evolution of metazoan communities, can now be depicted. Moreover, recent studies have substantially clarified the biostratigraphical and palaeoenvironmental context of the Fezouata Shale, and are now being followed up by detailed investigations of the taphonomy, geochemistry and micropalaeontology of this unique Konservat-Lagerstätte. These efforts will soon greatly benefit from the recovery of fresh, unweathered samples from drill cores.
Research Interests:
Research Interests: Evolutionary Biology, Marine Biology, Paleobiology, Paleontology, Palaeoenvironment, and 29 morePaleoecology, Biology, Evolution, Palaeoecology, Evolutionary Ecology, Palaeontology, Invertebrate Paleontology, Paleozoic communities, Biological Sciences, Palaeozoic palaeoenvironments, Ordovician, Paleozoology, Palaeozoic, Palaeozoic stratigraphy and palaeontology, Paleozoic, Morocco Ordovician Fezouata Lagerstatte, Fezouata, Ordovician Lagerstatten, Evolution and Phylogeny of Metazoan, Lagerstätte, Early Palaeozoic, Lagerstatten, Metazoan Origins, Metazoa, Ordovician Paleoecology, Konservat Lagerstatten, Fezouata Biota, Origins of Metazoans, and Great Ordovician Biodiversification Event
Specimens of Euproops sp. (Xiphosura, Chelicerata) from the Carboniferous Piesberg quarry near Osnabrück, Germany, represent a relatively complete growth series of 10 stages. Based on this growth sequence, morphological changes throughout... more
Specimens of Euproops sp. (Xiphosura, Chelicerata)
from the Carboniferous Piesberg quarry near Osnabrück,
Germany, represent a relatively complete growth series of 10
stages. Based on this growth sequence, morphological changes
throughout the ontogeny can be identified. The major change
affects the shape of the epimera of the opisthosoma. In earlier
stages, they appear very spine-like, whereas in later stages the
bases of these spine-like structures become broader; the broadened bases are then successively drawn out distally. In the most mature stage known, the epimera are of trapezoidal shape and approach each other closely to form a complete flange around the thoracetron (fused tergites of the opisthosoma). These ontogenetic changes question the taxonomic status of different species of Euproops, as the latter appear to correspond to different stages of the ontogenetic series reconstructed from the Piesberg specimens. This means that supposed separate species could, in fact, represent different growth stages of a single species. It could alternatively indicate that heterochrony (evolutionary change of developmental timing) plays an important role in the evolution of Xiphosura. We propose a holomorph approach, i.e., reconstructing ontogenetic sequences for fossil and extant species as a sound basis for a taxonomic, phylogenetic, and evolutionary discussion of Xiphosura.
from the Carboniferous Piesberg quarry near Osnabrück,
Germany, represent a relatively complete growth series of 10
stages. Based on this growth sequence, morphological changes
throughout the ontogeny can be identified. The major change
affects the shape of the epimera of the opisthosoma. In earlier
stages, they appear very spine-like, whereas in later stages the
bases of these spine-like structures become broader; the broadened bases are then successively drawn out distally. In the most mature stage known, the epimera are of trapezoidal shape and approach each other closely to form a complete flange around the thoracetron (fused tergites of the opisthosoma). These ontogenetic changes question the taxonomic status of different species of Euproops, as the latter appear to correspond to different stages of the ontogenetic series reconstructed from the Piesberg specimens. This means that supposed separate species could, in fact, represent different growth stages of a single species. It could alternatively indicate that heterochrony (evolutionary change of developmental timing) plays an important role in the evolution of Xiphosura. We propose a holomorph approach, i.e., reconstructing ontogenetic sequences for fossil and extant species as a sound basis for a taxonomic, phylogenetic, and evolutionary discussion of Xiphosura.
Research Interests: Paleobiology, Paleontology, Invertebrate Biology, Invertebrates, Invertebrate Zoology, and 22 morePalaeontology, Invertebrate Paleontology, Aquatic Invertebrates, Ontogeny, Arthropoda, Carboniferous, Xiphosuran, Arthropod, Marine invertebrates, Arthropods, Fossil Chelicerates, Largerstatte, Fossils Cambrian to Devonian.fossil chelicerates,eurypterid fossils especially of N.E. North America, Arthropod palaeobiology, Arthropod comparative morphology, Permo-Carboniferous fauna, Xiphosura, Chelicerate, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Fossil Arthropods, Chelicerata, and Konservat Lagerstatten
The Carboniferous eurypterid Eurypterus dumonti STAINIER, 1917 from Mechelen-aan-de-Maas (Maasmechelen), Belgium is redescribed and assigned to the genus Adelophthalmus. It is diagnosed as having a raised triangle of unknown function,... more
The Carboniferous eurypterid Eurypterus dumonti STAINIER, 1917 from Mechelen-aan-de-Maas (Maasmechelen), Belgium is redescribed and assigned to the genus Adelophthalmus. It is diagnosed as having a raised triangle of unknown function, dorsally on opisthosomal segment 7 and a carapace articulating laterally against the second opisthosomal segment. Earlier assignments of this species to the genus Unionopterus, based on the carapace shape figured in the original description (STAINIER 1917), are incorrect and the existence of a Carboniferous eurypterid with the characteristics described for Unionopterus must be questioned. The appendages in A. dumonti are completely exposed and provide an unrivalled insight into the number of appendage podomeres in the genus; this species is interpreted to have a podomere count consistent with most other eurypterids. Small pustules previously thought to be cuticle sculpture are here interpreted as diagenetic``dumb-bells'' (see BRIGGS & WILBY 1996) following microbial activity on the carcase prior to fossilisation. Thesè`dumb-bells'' are the oldest non-marine record of this diagenetic feature. A number of other features are also interpreted differently from the original description. Possible lineages within the Adelophthalmus clade are identified, A. dumonti is probably closely related to A. imhofi (Czech Republic) and A. moyseyi (United Kingdom).
Research Interests: Evolutionary Biology, Marine Biology, Paleontology, Invertebrate Biology, Invertebrates, and 39 moreBiology, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Biological Sciences, Arthropoda, Palaeontology，Sedimentology，stratigraphy, Fossils, Carboniferous, Eurypterid, Arthropod, Eurypterid Anatomy, Palaeozoic stratigraphy and palaeontology, Paleontologia, Paleobotany; Paleontology; Paleoecology, Marine invertebrates, Arthropods, Invertebrate Palaeontology, Fossil Chelicerates, Geology and Paleontology, Largerstatte, Fossils Cambrian to Devonian.fossil chelicerates,eurypterid fossils especially of N.E. North America, Arthropod palaeobiology, Paleontología, Invertebrate Taxonomy, Arthropod comparative morphology, Eurypterida, Eurypterids, Chelicerate, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Fossil Arthropods, Chelicerata, Taxonomy of Marine Invertebrates, Carboniferous Eurypterid, Konservat Lagerstatten, Eurypterid Carboniferous, Eurypterid Evolution, Eurypterids Phylogeny, and Eurypterid Taxonomy
A highly spinose fragment of a possibly raptorial appendage from the Arenig (Early Ordovician) of the Upper Fezouata Formation north of Zagora, southeastern Morocco is described as the arthropod Pseudoangustidontus duplospineus gen. et... more
A highly spinose fragment of a possibly raptorial appendage from the Arenig (Early Ordovician) of the Upper Fezouata Formation north of Zagora, southeastern Morocco is described as the arthropod Pseudoangustidontus duplospineus gen. et sp. nov. The single fragmentary specimen displays a unique morphology, carrying at least 39 pairs of spines (i.e., 78 spines) of very regularly alternating lengths. Pseudoangustidontus gen. nov. shows some similarities to a number of spinose arthropod appendages and appendage parts, most notably to the spine−bearing podomeres of the third prosomal appendage of megalograptid eurypterids and the problematic and incompletely known genus Angustidontus. However, megalograptids and Angustidontus both have a lower spine count, while the latter also carries only a single row of spines. Because no known arthropod displays a morphology closely comparable to that of Pseudoangustidontus gen. nov., the af− finities of the new fossil within Arthropoda remain uncertain.
Research Interests: Evolutionary Biology, Marine Biology, Paleontology, Invertebrate Biology, Invertebrates, and 27 moreBiology, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Aquatic Invertebrates, Biological Sciences, Arthropoda, Palaeontology，Sedimentology，stratigraphy, Ordovician, Biologia, Invertebrados, Arthropod, Palaeozoic stratigraphy and palaeontology, Paleontologia, Morocco Ordovician Fezouata Lagerstatte, Marine invertebrates, Arthropods, Invertebrate Palaeontology, Fezouata, Arthropod palaeobiology, Invertebrate Taxonomy, Arthropod comparative morphology, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Fossil Arthropods, Konservat Lagerstatten, and Fezouata Biota
The taxon Arthropoda has been repeatedly cited with various incorrect authorship data. Here, we review the primary literature and show the correct citation to be 'Arthropoda Von Siebold, 1848'.
Research Interests:
The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very few Konservat-Lagerstätten known so far in the world to have yielded numerous remains of Late Ordovician softbodied fossils associated with... more
The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one
of the very few Konservat-Lagerstätten known so far in the world to have yielded
numerous remains of Late Ordovician softbodied fossils associated with an abundant and diverse marine benthic fauna. This locality has also yielded several levels (starfish beds) extremely rich in exquisitely preserved echinoderms. Their remarkable preservation possibly results from the rapid, in situ burial of large, particularly dense, living communities (echinoderm meadows) by storm deposits. The Bou Nemrou starfish beds are dominated by eocrinoids and stylophorans, associated with crinoids, cyclocystoids, edrioasteroids, and ophiuroids. This composition is typical of the cool assemblages of the Mediterranean Province. The Bou Nemrou starfish beds may result from the opportunistic colonisation of the sea-floor by dense populations of echinoderms, during short phases of environmental disturbance.
of the very few Konservat-Lagerstätten known so far in the world to have yielded
numerous remains of Late Ordovician softbodied fossils associated with an abundant and diverse marine benthic fauna. This locality has also yielded several levels (starfish beds) extremely rich in exquisitely preserved echinoderms. Their remarkable preservation possibly results from the rapid, in situ burial of large, particularly dense, living communities (echinoderm meadows) by storm deposits. The Bou Nemrou starfish beds are dominated by eocrinoids and stylophorans, associated with crinoids, cyclocystoids, edrioasteroids, and ophiuroids. This composition is typical of the cool assemblages of the Mediterranean Province. The Bou Nemrou starfish beds may result from the opportunistic colonisation of the sea-floor by dense populations of echinoderms, during short phases of environmental disturbance.
Research Interests: Paleobiology, Paleontology, Invertebrate Biology, Invertebrates, Echinoderms, and 33 morePalaeoecology, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Paleozoic communities, Echinodermata, Aquatic Invertebrates, Ordovician, Crinoids, Palaeozoic, Ordovician echinoderms, Upper Ordovician, Asteroidea, Starfish, Palaeozoic stratigraphy and palaeontology, Paleozoic, Ophiuroidea, Crinoidea, Early Paleozoic echinoderms, Marine invertebrates, Stylophora, Exceptional fossilization, Paleozoic Echinoderms (Specifically Crinoids), Echinoderms Biodiversity, Invertebrate Taxonomy, Echinoderm Taxonomy, Echinoderm, Eocrinoidea, Starfish Ecology, Ordovician Paleoecology, Exceptional Fossil Preservation, Konservat Lagerstatten, and Great Ordovician Biodiversification Event
Four distinct echinoderm Lagerstätten have recently been discovered in the Upper Ordovician of the eastern Anti-Atlas, Morocco. They have yielded hundreds of exquisitely preserved specimens. Their taphonomy and associated lithology both... more
Four distinct echinoderm Lagerstätten have recently been discovered in the Upper Ordovician of the eastern Anti-Atlas, Morocco. They have yielded hundreds of exquisitely preserved specimens. Their taphonomy and associated lithology both suggest rapid, in situ burial. Here we discuss the diverse range of assemblages represented and their significance to the diversity of echinoderms in the Lower Palaeozoic. The oldest assemblage (Izegguirene Formation, lowermost Caradoc) is dominated by eocrinoids, large ophi-uroids, and mitrate stylophorans associated with rare crinoids. It shows strong similarities with slightly older faunas described from the underlying Ouine-Inirne Formation (Llandeilian) in the Central Anti-Atlas. The second assemblage (lower part of the Lower Ktaoua Formation, lower-middle Caradoc) is composed of eocrinoids (Cardiocystites) and small ophiuroids (encrinasterid indet.). The third assemblage was collected in the upper part of the Lower Ktaoua Formation (lowermost Ashgill). This 'starfish' bed is dominated by ophiuroids and large solutes, associated with common diploporites and rhombiferans, and rare crinoids and mitrates. Finally, the youngest assemblage (lower part of Upper Tiouririne Formation, lower Ashgill) has yielded abundant remains of edrioasteroids and rhombiferans.
Research Interests: Evolutionary Biology, Marine Biology, Paleobiology, Paleontology, Biology, and 23 moreEchinoderms, Palaeontology, Invertebrate Paleontology, Echinodermata, Biological Sciences, Palaeontology，Sedimentology，stratigraphy, Ordovician, Biologia, Fossils, Ordovician echinoderms, Upper Ordovician, Paleontologia, Early Paleozoic echinoderms, Invertebrate Palaeontology, Geology and Paleontology, Lagerstätte, Paleontología, Echinoderms Biodiversity, Lagerstatten, Echinoderm Taxonomy, Echinoderm, Ordovician Paleoecology, and Konservat Lagerstatten
Plusieurs Lagerstätten à échinodermes ont été découverts au cours des dix dernières années dans l'Ordovicien supérieur de l'Anti-Atlas oriental (Tafilalt occidental, Maroc). Ces niveaux ont livré des assemblages particulièrement riches et... more
Plusieurs Lagerstätten à échinodermes ont été découverts au cours des dix dernières années dans l'Ordovicien supérieur de l'Anti-Atlas oriental (Tafilalt occidental, Maroc). Ces niveaux ont livré des assemblages particulièrement riches et diversifiés d'échinodermes. La préservation exceptionnelle de ces organismes témoigne d'un enfouissement rapide et in situ de communautés benthiques particulièrement denses constituées quasi-exclusivement d'échinodermes. Trois assemblages sont décrits : Bou Nemrou (Sandbien basal), piste de Jorf (Sandbien supérieur) et enfin, Tizi n'Mouri (Katien supérieur). L'intérêt scientifique majeur de ces faunes (implications paléoécologiques et paléogéographiques) est brièvement présenté. Enfin, la préservation de ces gisements, qui constituent un élément majeur du patrimoine paléontologique du Sud marocain, est abordée. Late Ordovician echinoderm Lagerstätten from the eastern Anti-Atlas (Morocco): an example of exceptional scientific heritage worthy of protection. Abstract. In the last ten years, several Late Ordovician echinoderm Lagerstätten have been discovered in the eastern Anti-Atlas (western Tafilalt) of Morocco. These levels have yielded extremely rich and diverse echinoderm assemblages. The exquisite preservation of most organisms suggests rapid and in-situ burial of large, particularly dense benthic communities largely dominated by echinoderms. Three « starfish beds » are briefly described: Bou Nemrou (earliest Sandbian), piste de Jorf (late Sandbian), and Tizi n'Mouri (late Katian). The major scientific relevance of these faunas is outlined herein (for example their palaeoecological and palaeogeographical implications). Finally, the conservation of these levels, which represent a major piece of the palaeontological heritage of southern Morocco, is discussed.
Research Interests: Evolutionary Biology, Marine Biology, Paleobiology, Paleontology, Invertebrate Biology, and 36 moreInvertebrates, Biology, Evolution, Echinoderms, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Echinodermata, Aquatic Invertebrates, Biological Sciences, Palaeontology，Sedimentology，stratigraphy, Ordovician, Biologia, Ordovician echinoderms, Invertebrados, Upper Ordovician, Palaeozoic stratigraphy and palaeontology, Paleontologia, Paleobotany; Paleontology; Paleoecology, Early Paleozoic echinoderms, Marine invertebrates, Invertebrate Palaeontology, Geology and Paleontology, Lagerstätte, Invertebrate ecology, Paleobiología, Paleontología, Echinoderms Biodiversity, Invertebrate Taxonomy, Lagerstatten, Echinoderm Taxonomy, Echinoderm, Ordovician Paleoecology, Taxonomy of Marine Invertebrates, Konservat Lagerstatten, and Zoologia De Invertebrados
Research Interests: Paleontology, Invertebrate Biology, Invertebrates, Invertebrate Zoology, Palaeontology, and 28 moreInvertebrate Paleontology, Aquatic Invertebrates, Arthropoda, Palaeontology，Sedimentology，stratigraphy, Cambrian, Invertebrados, Arthropod, Palaeozoic stratigraphy and palaeontology, Paleontologia, Paleobotany; Paleontology; Paleoecology, Burgess Shale, Cambrian explosion, Marine invertebrates, Arthropods, Invertebrate Palaeontology, Geology and Paleontology, Arthropod palaeobiology, Cambrian and Precambrian, Marrellomorpha, Cambrian Fossils, Paleontología, Invertebrate Taxonomy, Arthropod comparative morphology, Palaeontology of arthropod and problematic fossils of the Ediacaran and early Palaeozoic, Arthropod Evolution, Fossil Arthropods, Taxonomy of Marine Invertebrates, and Zoologia De Invertebrados
Palaeoscolecidan worms are rare, Early Palaeozoic fossils with uncertain affinities within the Ecdysozoa. They are locally abundant in the Cambrian and scattered in the Early Ordovician, but very sparse thereafter. Forty-four specimens... more
Palaeoscolecidan worms are rare, Early Palaeozoic fossils with uncertain affinities within the Ecdysozoa. They are locally abundant in the Cambrian and scattered in the Early Ordovician, but very sparse thereafter. Forty-four specimens have been collected from the Middle Ordovician of the Builth-Llandrindod Inlier of Mid Wales and include well-preserved material assigned to seven new genera, with four additional species in open nomenclature. An additional specimen from the Arenig Pontyfenni Formation of South Wales is also described in open nomenclature. The total demonstrates much greater palaeoscolecid diversity than hitherto suspected for this time. The specimens are preserved as cuticle fragments in shales and siltstones, often of submillimetre size but in many cases with excellent preservation. The level of detail preserved in some is equal to that found in Cambrian phosphatized faunas. The new approach to collecting, and the recognition that this material can yield taxonomically useful information, opens new avenues for palaeoscolecidan research in siliciclastic environments. The new taxa are the following: Radnorscolex bwlchi gen. et sp. nov., Aggerscolex murchisoni gen. et sp. nov., Bullascolex inserere gen. et sp. nov., Wernia eximia gen. et sp. nov., Ulexiscolex ormrodi gen. et sp. nov., Pluoscolex linearis gen. et sp. nov. and Loriciscolex cuspidus gen. et sp. nov. The high diversity, and the taxonomic separation from known groups described primarily from Cambrian carbonates, implies that palaeoscolecidans either diversified significantly during the Ordovician or were taxonomically segregated between car-bonate and siliciclastic settings. Palaeobiological findings also include confirmation that some palaeoscolecid basal cuticles were solid and others reticulate, plates (and platelets) could form by lateral accretion, plates were in part primarily phos-phatic and in part organic and that in at least some groups, platelet secretion occurred external to plate secretion.
Research Interests: Paleobiology, Zoology, Paleontology, Invertebrate Biology, Invertebrates, and 11 moreInvertebrate Zoology, Palaeontology, Invertebrate Paleontology, Palaeoscolecidans, Ordovician, Marine invertebrates, Invertebrate Palaeontology, Evolution and Phylogeny of Metazoan, Ecdysozoa, Invertebrate Taxonomy, and Metazoa
A newly discovered locality of an hitherto unknown age, but now estimated to the Late Ordovician, in south-eastern Morocco has yielded numerous specimens of problematic soft-bodied metazoans preserved in coarse sandstones. The excellent... more
A newly discovered locality of an hitherto unknown age, but now estimated to the Late Ordovician, in south-eastern Morocco has yielded numerous specimens of problematic soft-bodied metazoans preserved in coarse sandstones. The excellent preservation of the recovered specimens permits an improved understanding of both the palaeobiology of these Ordovician metazoans and the taphonomic processes associated with them. This style of soft tissue preservation is closely comparable to that of the late Neoproterozoic problematic Ediacaran organisms, and is virtually absent in the Phanerozoic. Palynological analysis (chitinozoans and acritarchs) of shaly intercalations in an ophiuroid-bearing sandstone slab facilitates accurate identification of the site as belonging to the Upper Ktaoua Formation and thus a relative dating of the associated fossils. The chitinozoan assemblage is relatively well preserved, moderately diverse and closely comparable to the previously described chitinozoan fauna from the Upper Ktaoua Formation (Rawtheyan, late middle Ashgill age). Acritarchs are abundant but mostly ill-preserved; nonetheless they clearly indicate an undifferentiated Ashgill age, consistent with the chitinozoan chronostratigraphic result. These datings prove that the newly discovered Moroccan metazoan assemblage contains one of the oldest
known paropsonemids, and possibly some of the youngest protolyelloids and aglaspidids. The new finds also show that Ediacara-like coarse-clastic preservation did not completely vanish with the onset of the Phanerozoic.
known paropsonemids, and possibly some of the youngest protolyelloids and aglaspidids. The new finds also show that Ediacara-like coarse-clastic preservation did not completely vanish with the onset of the Phanerozoic.
Research Interests: Paleontology, Stratigraphy, Palynology, Micropaleontology, Micropalaeontology, and 15 morePalaeontology, Sedimentary geology and stratigraphy, Ordovician, Marine Micropaleontology; Marine Paleoenvironments, Upper Ordovician, Geology, Micropaleontology, Geology, Micropalaeontology, Palynology, biostratigraphy, palaoenvironments, Micropaleontology, Biostratigraphy, Micropaleontologia, Micropaleontology, Marine Geology, Ordovician Stratigraphy, Micropaléontologie, Palynologie, and Micropalentology
The Weeks Formation in Utah is the youngest (c. 499 Ma) and least studied Cambrian Lagerstätte of the western USA. It preserves a diverse, exceptionally preserved fauna that inhabited a relatively deep water environment at the offshore... more
The Weeks Formation in Utah is the youngest (c. 499 Ma) and least studied Cambrian Lagerstätte of the western USA. It preserves a diverse, exceptionally preserved fauna that inhabited a relatively deep water environment at the offshore margin of a carbonate platform, resembling the setting of the underlying Wheeler and Marjum formations. However, the Weeks fauna differs significantly in composition from the other remarkable biotas of the Cambrian Series 3 of Utah, suggesting a significant Guzhangian faunal restructuring. This bioevent is regarded as the onset of a transitional episode in the history of life, separating the two primary diversifications of the Early Paleozoic. The Weeks fossils have been strongly affected by late diagenetic processes, but some specimens still preserve exquisite anatomical details. Supplementary material: a supplementary text (material and methods), four supplementary tables (compositions of the lower and upper Weeks faunas, structure of the upper Weeks fauna, and results of the similarity analyses), and a supplementary data file (generic presence/absence matrix) are available at https://doi.
Research Interests:
Palaeoscolecids are long cylindrical annulated vermiform ecdysozoans with an eversible proboscis comparable with that of priapulids. Their most conspicious external feature are aligned knob-like sclerites of assumed primary phosphatic... more
Palaeoscolecids are long cylindrical annulated vermiform ecdysozoans with an eversible proboscis comparable with that of priapulids. Their most conspicious external feature are aligned knob-like sclerites of assumed primary phosphatic origin associated to the annulations of their molting cuticle. Recent cladistic analyses indicate that palaeoscolecids probably belong to the stem lineage Priapulida. Their fossil record ranges from the early Cambrian to the late Silurian, but only isolated sclerites or small clusters of sclerites are usually found in sediments as SSF or SCF. By contrast, complete animals are relatively rare except in some Early Cambrian Lagerstätten such as in Chengjiang. Here are reported virtually complete specimens from several localities of Utah and Morocco which give important information on the anatomy, ecology and distribution of Palaeoscolecida through the Cambrian-Ordovician transition. Two specimens were recovered from the Issafen Formation (Cambrian Series ...
Research Interests:
Arthropods first appear in the fossil record some 530 million years ago. These joint-legged animals are the most species-rich and diverse animal group on Earth. The familiar creatures are virtually ubiquitous: horseshoe
Research Interests:
The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very few Konservat-Lagerstätten known so far in the world to have yielded numerous remains of Late Ordovician softbodied fossils associated with... more
The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very few Konservat-Lagerstätten known so far in the world to have yielded numerous remains of Late Ordovician softbodied fossils associated with an abundant and diverse marine benthic fauna. This locality has also yielded several levels (starfish beds) extremely rich in exquisitely preserved echinoderms. Their remarkable preservation possibly results from the rapid, in situ burial of large, particularly dense, living communities (echinoderm meadows) by storm deposits. The Bou Nemrou starfish beds are dominated by eocrinoids and stylophorans, associated with crinoids, cyclocystoids, edrioasteroids, and ophiuroids. This composition is typical of the cool assemblages of the Mediterranean Province. The Bou Nemrou starfish beds may result from the opportunistic colonisation of the sea-floor by dense populations of echinoderms, during short phases of environmental disturbance.
Research Interests: Invertebrate Biology, Invertebrates, Echinoderms, Invertebrate Zoology, Invertebrate Paleontology, and 15 moreEchinodermata, Aquatic Invertebrates, Crinoids, Asteroidea, Crinoidea, Early Paleozoic echinoderms, Exceptional fossilization, Echinoderms Biodiversity, Invertebrate Taxonomy, Echinoderm Taxonomy, Echinoderm, Eocrinoidea, Exceptional Fossil Preservation, Konservat Lagerstatten, and Great Ordovician Biodiversification Event
Research Interests:
Most of our knowledge of Neoproterozoic metazoans comes from Lagerstätten preserving fossils as moulds and casts in siliciclastic sediments. Until recently, such Lagerstätten were believed to be unique to the Neoproterozoic, and although... more
Most of our knowledge of Neoproterozoic metazoans comes from Lagerstätten preserving fossils as moulds and casts in siliciclastic sediments. Until recently, such Lagerstätten were believed to be unique to the Neoproterozoic, and although significant advances have been made in recent years, our incomplete understanding of this taphonomic mode remains the limiting factor in our comprehension of these fossils. A key factor in this limited understanding has been that all specimens known in this style of preservation are to some ...
Research Interests:
Research Interests: Evolutionary Biology, Marine Biology, Paleontology, Invertebrate Biology, Invertebrates, and 26 moreBiology, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Aquatic Invertebrates, Biological Sciences, Palaeontology，Sedimentology，stratigraphy, Ordovician, Biologia, Upper Ordovician, Palaeozoic stratigraphy and palaeontology, Paleontologia, Morocco Ordovician Fezouata Lagerstatte, Paleobotany; Paleontology; Paleoecology, Marine invertebrates, Invertebrate Palaeontology, Geology and Paleontology, Fezouata, Ordovician Lagerstatten, Lagerstätte, Invertebrate ecology, Paleontología, Lagerstatten, Ordovician Paleoecology, Konservat Lagerstatten, and Fezouata Biota
Exceptionally preserved fossils yield crucial information about the evolution of Life on Earth. The Fezouata Biota from the Lower Ordovician of Morocco is a Konservat-Lagerstätte of major importance, and it is today considered as an... more
Exceptionally preserved fossils yield crucial information about the evolution of Life on Earth. The Fezouata Biota from the Lower Ordovician of Morocco is a Konservat-Lagerstätte of major importance, and it is today considered as an 'Ordovician Burgess Shale.' This biota was discovered only some 15 years ago, but geological studies of the area date back to the beginning of the 20th century. Pioneering geological investigations lead to the discovery of Ordovician strata in the Anti-Atlas (1929) and ultimately resulted in their formal subdivision into four main strat-igraphic units (1942). In the Agdz area, the presence of fossiliferous Tremadocian (Lower Ordovician) strata was suspected as early as 1939, but only definitively confirmed in 1955. In the 1960s–1990s, Jacques Destombes provided the first detailed biostratigraphic framework for the Lower Ordovician of the Anti-Atlas, and collected thousands of fossils that were subsequently described in a series of monographs. In the early 2000s, exceptionally preserved fossils were discovered in the Fezouata Shale (Tremadocian–late Floian) in the central Anti-Atlas by Mohamed 'Ou Saïd' Ben Moula. This biota, now known as the Fezouata Biota, is of utmost importance, for it demonstrates the extent in the fossil record of non-biomineralising animals typical of the 'Cambrian Explosion' into the Ordovician, during the 'Great Ordovician Biodiversification.' Although most components are still in need of formal descriptions, a fairly good picture of the composition and organisation of this biota, and how it contributes to our understanding of the early evolution of metazoan communities, can now be depicted. Moreover, recent studies have substantially clarified the biostratigraphical and palaeoenvironmental context of the Fezouata Shale, and are now being followed up by detailed investigations of the taphonomy, geochemistry and micropalaeontology of this unique Konservat-Lagerstätte. These efforts will soon greatly benefit from the recovery of fresh, unweathered samples from drill cores.
Research Interests: Paleontology, History of Paleontology, Invertebrate Biology, Invertebrates, Biology, and 25 morePalaeoecology, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Aquatic Invertebrates, History of Palaeontology, Palaeontology，Sedimentology，stratigraphy, Ordovician, Ordovician echinoderms, Palaeozoic stratigraphy and palaeontology, Paleontologia, Morocco Ordovician Fezouata Lagerstatte, Paleobotany; Paleontology; Paleoecology, Marine invertebrates, Invertebrate Palaeontology, Geology and Paleontology, Fezouata, Paleontología, Stratigraphy and Paleontology, Ordovician Stratigraphy, Ordovician Paleoecology, Konservat Lagerstatten, Fezouata Biota, Upper Fezouata Formation, and Great Ordovician Biodiversification Event
Since the first discovery some 12 years ago of non-biomineralised fossils in the Tremadocian of the Lower Fezouata Formation north of Zagora, south-eastern. Morocco, the Fezouata Biota has become one of the world's most important... more
Since the first discovery some 12 years ago of non-biomineralised fossils in the Tremadocian of the Lower Fezouata Formation north of Zagora, south-eastern. Morocco, the Fezouata Biota has become one of the world's most important marine Konservat-Lagerstäitten, being the only exceptionally preserved fauna to document the critical Cambro-Ordovician faunal transition. It has revolutionized our understanding of Ordovician marine ecosystems, showing that Burgess Shale-type faunas, long thought to have disappeared after the middle Cambrian, continued to flourish well into the Ordovician while co-occurring with a host of remarkably derived, typical post-Cambrian organisms, many of which had been believed to have appeared much later. These findings indicate that the turnover between the Cambrian and Palaeozoic Evolutionary Faunas was more protracted than hitherto realized, while the presence of several surprisingly advanced forms in the biota suggests that at least in some non-biominer...
Research Interests:
The Weeks Formation in Utah is the youngest (c. 499 Ma) and least studied Cambrian Lagerstätte of the western USA. It preserves a diverse, exceptionally preserved fauna that inhabited a relatively deep water environment at the offshore... more
The Weeks Formation in Utah is the youngest (c. 499 Ma) and least studied Cambrian Lagerstätte of the western USA. It preserves a diverse, exceptionally preserved fauna that inhabited a relatively deep water environment at the offshore margin of a carbonate platform, resembling the setting of the underlying Wheeler and Marjum formations. However, the Weeks fauna differs significantly in composition from the other remarkable biotas of the Cambrian Series 3 of Utah, suggesting a significant Guzhangian faunal restructuring. This bioevent is regarded as the onset of a transitional episode in the history of life, separating the two primary diversifications of the Early Paleozoic. The Weeks fossils have been strongly affected by late diagenetic processes, but some specimens still preserve exquisite anatomical details.Supplementary material: a supplementary text (material and methods), four supplementary tables (compositions of the lower and upper Weeks faunas, structure of the upper Weeks...
Research Interests: Biology, Biostratigraphy, Biological Sciences, Arthropoda, Cambrian, and 15 moreBiologia, Cambrian Ecosystem, Arthropod, Chengjiang Lagerstatte, Burgess Shale, Cambrian explosion, Arthropods, Arthropod palaeobiology, Cambrian and Precambrian, Cambrian Fossils, Chengjiang biota, Cambrian Trilobite, Arthropod Evolution, Cambrian Trilobites, and Cambrian Ecology
Abstract: Palaeoscolecidan worms are rare, Early Palaeozoic fossils with uncertain affinities within the Ecdysozoa. They are locally abundant in the Cambrian and scattered in the Early Ordovician, but very sparse thereafter. Forty-four... more
Abstract: Palaeoscolecidan worms are rare, Early Palaeozoic fossils with uncertain affinities within the Ecdysozoa. They are locally abundant in the Cambrian and scattered in the Early Ordovician, but very sparse thereafter. Forty-four specimens have been collected from the Middle Ordovician of the Builth-Llandrindod Inlier of Mid Wales and include well-preserved material assigned to seven new genera, with four additional species in open nomenclature. An additional specimen from the Arenig Pontyfenni Formation of South Wales is also ...
Research Interests: Evolutionary Biology, Geology, Invertebrate Biology, Invertebrates, Ecology, and 15 moreChina, Invertebrate Zoology, Palaeontology, Invertebrate Paleontology, Ordovician, Fossils, Deposits, Cuticle, Marine invertebrates, Invertebrate Palaeontology, Evolution and Phylogeny of Metazoan, Ecdysozoa, Faunas, Invertebrate Taxonomy, and Metazoa
Research Interests: Marine Biology, Paleobiology, Zoology, Earth Sciences, Paleontology, and 23 moreMorphology, Evolution, Morocco, Taphonomy, Biodiversity, Palaeontology, Multidisciplinary, Palaeobiology, Soft Tissue Preservation, Nature, Invertebrate Paleontology, Graptolites, Ordovician, Fossils, Animals, Fauna, Extinction, Paleozoic, Morocco Ordovician Fezouata Lagerstatte, Basin, Fezouata, Shale, and Sedimentary Rocks
Keywords: Konservat-Lagerstätten Sedimentology Ordovician Gondwana Morocco Fezouata The Lower Ordovician Fezouata Konservat-Lagerstätte from southern Morocco has been one of the major palaeontological discoveries of the last decade. It... more
Keywords: Konservat-Lagerstätten Sedimentology Ordovician Gondwana Morocco Fezouata The Lower Ordovician Fezouata Konservat-Lagerstätte from southern Morocco has been one of the major palaeontological discoveries of the last decade. It provides a unique insight into one of the most critical periods in the evolution of marine life: the Cambrian–Ordovician transition. However, its potential for deciphering key trends in animal diversification was hitherto largely limited by major uncertainties concerning its stratigraphic position, age and environmental setting. Based on extensive fieldwork, fossil evidence, and facies recognition, our study provides clarification on these three crucial issues. Exceptional preservation is limited to two intervals within the Fezouata Shale. Graptolites indicate a late Tremadocian age for the Fezouata Konservat-Lagerstätte as a whole, which is supported by biostratigraphical evidence provided by acritarchs. Sedimentological features and reconstructed patterns of relative sea-level changes indicate relatively shallow-water environmental conditions, under distal storm influence, in an offshore to lower shoreface siliciclastic ramp setting. The Fezouata Biota represents a unique and exceptional window into the palaeobiodiversity in open-marine conditions, thus contrasting with the other Ordovician Konservat-Lagerstätten presently known. In our analyses of this new set of data, we pave the way for accurate temporal, faunal and environmental comparisons with other Lower Palaeozoic Konservat-Lagerstätten, and unlock the full potential of the Fezouata Biota to better understand the processes and scenarios of early animal radiations.
Research Interests:
Research Interests: Evolutionary Biology, Marine Biology, Geology, Biology, Echinoderms, and 15 moreInvertebrate Paleontology, Echinodermata, Biological Sciences, Ordovician, Biologia, Fossils, Early Paleozoic echinoderms, Invertebrate Palaeontology, Geology and Paleontology, Lagerstätte, Echinoderms Biodiversity, Lagerstatten, Echinoderm Taxonomy, Echinoderm, and Konservat Lagerstatten
Résumé Le site de Bou Nemrou, situé dans le Tafilalt occidental (Anti-Atlas oriental, Maroc) compte parmi les rares gisements à préservation exceptionnelle (Lagerstätten) connus actuellement dans l'Ordovicien supérieur à avoir livré... more
Résumé Le site de Bou Nemrou, situé dans le Tafilalt occidental (Anti-Atlas oriental, Maroc) compte parmi les rares gisements à préservation exceptionnelle (Lagerstätten) connus actuellement dans l'Ordovicien supérieur à avoir livré des restes d'organismes peu ou pas minéralisés, ...