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  • 1. Altenburger, Andreas
    et al.
    Martinez, Pedro
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Holmer, Lars E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Gene Expression Patterns in Brachiopod Larvae Refute the "€œBrachiopod-Fold"€ Hypothesis2017In: Frontiers in Cell and Developmental Biology, Vol. 5, p. 1-3, article id 74Article in journal (Refereed)
  • 2.
    Budd, Graham
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Early animal evolution and the origins of nervous systems2015In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 370, no 1684, article id 20150037Article in journal (Refereed)
    Abstract [en]

    Understanding the evolution of early nervous systems is hazardous because we lack good criteria for determining homology between the systems of distant taxa; the timing of the evolutionary events is contested, and thus the relevant ecological and geological settings for them are also unclear. Here I argue that no simple approach will resolve the first issue, but that it remains likely that animals evolved relatively late, and that their nervous systems thus arose during the late Ediacaran, in a context provided by the changing planktonic and benthic environments of the time. The early trace fossil provides the most concrete evidence for early behavioural diversification, but it cannot simply be translated into increasing nervous system complexity: behavioural complexity does not map on a one-to-one basis onto nervous system complexity, both because of possible limitations to behaviour caused by the environment and because we know that even organisms without nervous systems are capable of relatively complex behaviour.

  • 3.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Animal Evolution: Trilobites on Speed2013In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 23, no 19, p. R878-R880Article in journal (Other academic)
  • 4.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    At the Origin of Animals: The Revolutionary Cambrian Fossil Record2013In: Current Genomics, ISSN 1389-2029, E-ISSN 1875-5488, Vol. 14, no 6, p. 344-354Article in journal (Refereed)
    Abstract [en]

    The certain fossil record of animals begins around 540 million years ago, close to the base of the Cambrian Period. A series of extraordinary discoveries starting over 100 years ago with Walcott's discovery of the Burgess Shale has accelerated in the last thirty years or so with the description of exceptionally-preserved Cambrian fossils from around the world. Such deposits of "Burgess Shale Type" have been recently complemented by other types of exceptional preservation. Together with a remarkable growth in knowledge about the environments that these early animals lived in, these discoveries have long exerted a fascination and strong influence on views on the origins of animals, and indeed, the nature of evolution itself. Attention is now shifting to the period of time just before animals become common, at the base of the Cambrian and in the preceding Ediacaran Period. Remarkable though the Burgess Shale deposits have been, a substantial gap still exists in our knowledge of the earliest animals. Nevertheless, the fossils from this most remarkable period of evolutionary history continue to exert a strong influence on many aspects of animal evolution, not least recent theories about developmental evolution.

  • 5.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Head structure in upper stem-group euarthropods2008In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 51, no 3, p. 561-573Article in journal (Refereed)
    Abstract [en]

    Continuing debate over the evolution and morphology of the arthropod head has led to considerable interest in the relevance of the evidence from the fossil record. However, dispute over homology and even presence of appendages and sclerites in Cambrian arthropods has resulted in widely differing views of their significance. The head structures of several important taxa, Fuxianhuia, Canadaspis, Odaraia, Chengjiangocaris and Branchiocaris are redescribed, revealing the essential similarity between them. In particular, all possessed an anterior sclerite, probably followed by a large posterior, ventral sclerite that is likely to be homologous to the hypostome of trilobites. The presence of a similar feature in Sanctacaris is also possible, but less well-supported. An anterior sclerite, usually bearing eyes, as in Fuxianhuia, appears to be a widespread feature of basal arthropods. Whether or not this sclerite represents an original articulating protocerebral segment on its own is, however, open to debate.

  • 6.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    International Congress on Invertebrate Morphology – plenary papers2010Collection (editor) (Other academic)
  • 7.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Palaeontology: Cambrian nervous wrecks2012In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 490, no 7419, p. 180-181Article in journal (Other academic)
  • 8.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    The earliest fossil record of the animals and its significance2008In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 363, no 1496, p. 1425-1434Article, review/survey (Refereed)
    Abstract [en]

    The fossil record of the earliest animals has been enlivened in recent years by a series of spectacular discoveries, including embryos, from the Ediacaran to the Cambrian, but many issues, not least of dating and interpretation, remain controversial. In particular, aspects of taphonomy of the earliest fossils require careful consideration before pronouncements about their affinities. Nevertheless, a reasonable case can now be made for the extension of the fossil record of at least basal animals (sponges and perhaps cnidarians) to a period of time significantly before the beginning of the Cambrian. The Cambrian explosion itself still seems to represent the arrival of the bilaterians, and many new fossils in recent years have added significant data on the origin of the three major bilaterian clades. Why animals appear so late in the fossil record is still unclear, but the recent trend to embrace rising oxygen levels as being the proximate cause remains unproven and may even involve a degree of circularity.

  • 9.
    Budd, Graham E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Daley, Allison C.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    The lobes and lobopods of Opabinia regalis from the middle Cambrian Burgess Shale2012In: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 45, no 1, p. 83-95Article in journal (Refereed)
    Abstract [en]

    Despite many papers devoted to it, the morphology of the Burgess Shale animal Opabinia regalis continues to excite controversy. In particular, the trunk region remains incompletely understood, leading to several recent attempts to interpret the fossil in radically different ways. New material of Opabinia from the Royal Ontario Museum and the Smithsonian collection, together with the recent description of comparative material of the Burgess Shale anomalocaridid Hurdia, help clarify details of its morphology, in particular with regards to the lateral lobes and setal blades. A recent reconstruction of the trunk lobes is rejected, and further evidence for the presence of trunk limbs is presented. Despite disagreements over its morphology, the phylogenetic placement of Opabinia is now relatively uncontroversial, although various derived aspects of its morphology complicate placing it precisely.

  • 10.
    Budd, Graham E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Meidla, Tonu
    Univerity of Tartu.
    Willman, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Fossils & rocks: geotourism in the central Baltic2011Book (Other (popular science, discussion, etc.))
  • 11.
    Budd, Graham
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Jackson, Illiam
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Ecological innovations in the Cambrian and the origins of the crown group phyla2016In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 371, no 1685Article in journal (Refereed)
    Abstract [en]

    Simulation studies of the early origins of the modern phyla in the fossil record, and the rapid diversification that led to them, show that these are inevitable outcomes of rapid and long-lasting radiations. Recent advances in Cambrian stratigraphy have revealed a more precise picture of the early bilaterian radiation taking place during the earliest Terreneuvian Series, although several ambiguities remain. The early period is dominated by various tubes and a moderately diverse trace fossil record, with the classical ‘Tommotian’ small shelly biota beginning to appear some millions of years after the base of the Cambrian at ca 541 Ma. The body fossil record of the earliest period contains a few representatives of known groups, but most of the record is of uncertain affinity. Early trace fossils can be assigned to ecdysozoans, but deuterostome and even spiralian trace and body fossils are less clearly represented. One way of explaining the relative lack of clear spiralian fossils until about 536 Ma is to assign the various lowest Cambrian tubes to various stem-group lophotrochozoans, with the implication that the groundplan of the lophotrochozoans included a U-shaped gut and a sessile habit. The implication of this view would be that the vagrant lifestyle of annelids, nemerteans and molluscs would be independently derived from such a sessile ancestor, with potentially important implications for the homology of their sensory and nervous systems.

  • 12.
    Budd, Graham
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Jensen, Sören
    Univ Extremadura, Fac Ciencias, Area Paleontol, Badajoz 06006, Spain.
    The origin of the animals and a ‘Savannah’ hypothesis for early bilaterian evolution2017In: Biological Reviews, ISSN 1464-7931, E-ISSN 1469-185X, Vol. 92, no 1, p. 446-473Article in journal (Refereed)
    Abstract [en]

    The earliest evolution of the animals remains a taxing biological problem, as all extant clades are highly derived and the fossil record is not usually considered to be helpful. The rise of the bilaterian animals recorded in the fossil record, commonly known as the ‘Cambrian explosion’, is one of the most significant moments in evolutionary history, and was an event that transformed first marine and then terrestrial environments. We review the phylogeny of early animals and other opisthokonts, and the affinities of the earliest large complex fossils, the so-called ‘Ediacaran’ taxa. We conclude, based on a variety of lines of evidence, that their affinities most likely lie in various stem groups to large metazoan groupings; a new grouping, the Apoikozoa, is erected to encompass Metazoa and Choanoflagellata. The earliest reasonable fossil evidence for total-group bilaterians comes from undisputed complex trace fossils that are younger than about 560 Ma, and these diversify greatly as the Ediacaran–Cambrian boundary is crossed a few million years later. It is generally considered that as the bilaterians diversified after this time, their burrowing behaviour destroyed the cyanobacterial mat-dominated substrates that the enigmatic Ediacaran taxa were associated with, the so-called ‘Cambrian substrate revolution’, leading to the loss of almost all Ediacara-aspect diversity in the Cambrian. Why, though, did the energetically expensive and functionally complex burrowing mode of life so typical of later bilaterians arise? Here we propose a much more positive relationship between late-Ediacaran ecologies and the rise of the bilaterians, with the largely static Ediacaran taxa acting as points of concentration of organic matter both above and below the sediment surface. The breaking of the uniformity of organic carbon availability would have signalled a decisive shift away from the essentially static and monotonous earlier Ediacaran world into the dynamic and burrowing world of the Cambrian. The Ediacaran biota thus played an enabling role in bilaterian evolution similar to that proposed for the Savannah environment for human evolution and bipedality. Rather than being obliterated by the rise of the bilaterians, the subtle remnants of Ediacara-style taxa within the Cambrian suggest that they remained significant components of Phanerozoic communities, even though at some point their enabling role for bilaterian evolution was presumably taken over by bilaterians or other metazoans. Bilaterian evolution was thus an essentially benthic event that only later impacted the planktonic environment and the style of organic export to the sea floor.

  • 13.
    Butler, Aodhán D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Cunningham, John A.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Donoghue, Philip C. J.
    Experimental taphonomy of Artemia reveals the role of endogenous microbes in mediating decay and fossilization2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1808, article id 20150476Article in journal (Refereed)
    Abstract [en]

    Exceptionally preserved fossils provide major insights into the evolutionary history of life. Microbial activity is thought to play a pivotal role in both the decay of organisms and the preservation of soft tissue in the fossil record, though this has been the subject of very little experimental investigation. To remedy this, we undertook an experimental study of the decay of the brine shrimp Artemia, examining the roles of autolysis, microbial activity, oxygen diffusion and reducing conditions. Our findings indicate that endogenous gut bacteria are the main factor controlling decay. Following gut wall rupture, but prior to cuticle failure, gut-derived microbes spread into the body cavity, consuming tissues and forming biofilms capable of 1 mediating authigenic mineralization, that pseudomorph tissues and structures such as limbs and the haemocoel. These observations explain patterns observed in exceptionally preserved fossil arthropods. For example, guts are preserved relatively frequently, while preservation of other internal anatomy is rare. They also suggest that gut-derived microbes play a key role in the preservation of internal anatomy and that differential preservation between exceptional deposits might be because of factors that control autolysis and microbial activity. The findings also suggest that the evolution of a through gut and its bacterial microflora increased the potential for exceptional fossil preservation in bilaterians, providing one explanation for the extreme rarity of internal preservation in those animals that lack a through gut.

  • 14.
    Daley, Allison
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Caron, Jean-Bernard
    A morphometric analysis of Hurdia, a dinocaridid from the Burgess Shale, Canada2007In: Lundadagarna i historisk geologi och paleontologi X: 12-13 March 2007 Abstracts with programme, 2007, p. 44-Conference paper (Other scientific)
  • 15.
    Daley, Allison
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Caron, Jean-Bernard
    Hurdia, a new anomalocaridid from the Burgess Shale and the origin of biramous limbs in arthropods2007In: 51st Palaeontological Association Annual Meeting: Programme with Abstracts, 2007, p. 29-30Conference paper (Other scientific)
  • 16.
    Daley, Allison C
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Caron, Jean-Bernard
    Morphology and systematics of the anomalocaridid arthropod Hurdia from the Middle Cambrian of British Columbia and Utah2013In: Journal of Systematic Palaeontology, ISSN 1477-2019, E-ISSN 1478-0941, Vol. 11, no 7, p. 743-787Article in journal (Refereed)
    Abstract [en]

    In Cambrian fossil Lagerstätten like the Burgess Shale, exceptionally preserved arthropods constitute a large part of the taxonomic diversity, providing opportunities to study the early evolution of this phylum in detail. The anomalocaridids, large presumed pelagic predators, are particularly relevant owing to their unique combination of morphological characters and basal position in the arthropod stem lineage. Although isolated elements and fragmented specimens were first discovered over 100 years ago, subsequent findings of more complete bodies ofAnomalocaris and Peytoia, especially in the 1980s, allowed for a better understanding of these enigmatic forms. Their evolutionary significance as stem group arthropods was further clarified by the recent discovery of a third anomalocaridid taxon, Hurdia. Here, examination of hundreds ofHurdia specimens from different stratigraphical layers within the Burgess Shale and Stephen Formation, combined with statistical analyses, provides a detailed description of the taphonomy, morphology and diversity of the genus and further elucidates anomalocaridid systematics. Hurdiais distinguished from other anomalocaridids in having mouthparts with extra rows of teeth, a large frontal carapace complex and diminutive swimming flaps with prominent setal structures. The two original species, H. victoria Walcott, 1912 and H. triangulata Walcott, 1912, are confirmed based on morphometric outline analyses of the frontal carapace components combined with stratigraphical evidence; a third species, Hurdia dentata Simonetta & Delle Cave, 1975, is synonymized with H. victoria. Morphology, preservation and stratigraphical distribution suggest that H. victoria and H. triangulata share the same type of frontal appendage; a second type of appendage, previously assigned to Hurdia (Morph A), belongs to Peytoia nathorsti. These and other morphological differences between the anomalocaridids may reflect different feeding strategies. Appendages and mouthparts of Hurdia indet. sp. are also identified from the Spence Shale Member of Utah, making Hurdia and Anomalocaris the most common and globally distributed anomalocaridid taxa.

  • 17.
    Eriksson, BJ
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. paleontologi.
    Larson, ET
    Thörnqvist, Per-Ove
    Faculty of Science and Technology, Biology, Department of Physiology and Developmental Biology. jämförande fysiologi.
    Tait, NN
    Budd, Graham E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. paleontologi.
    Expression of engrailed in the developing brain and appendages of the onychophoran Euperipatoides kanangrensis (Reid)2005In: JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION, Vol. 304, no 3, p. 220-228Article in journal (Refereed)
    Abstract [en]

    We have cloned an engrailed-class gene in the onychophoran Euperipatoides kanangrensis and investigated its expression using in situ hybridisation. The expression pattern was found to differ drastically from that previously described for another onychophoran species. In the present investigation, engrailed transcripts were detected in a subset of developing neurons in the brain anlage, and in the mesoderm as well as ectoderm of the developing limb buds. The engrailed positive cells of the brain are of differing developmental maturity, ranging from subepidermal neuronal precursors to neurons located basally in the embryo with developing axons. The lack of the traditional expression in the posterior compartment of segments reported earlier in onychophorans is discussed, and we suggest that onychophorans may have acquired two copies of engrailed with different functions.

  • 18.
    Eriksson, Bo Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Tait, Noel N.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Janssen, Ralf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Akam, Michael
    Head patterning and Hox gene expression in an onychophoran and its implications for the arthropod head problem2010In: Development, Genes and Evolution, ISSN 0949-944X, E-ISSN 1432-041X, Vol. 220, no 3-4, p. 117-122Article in journal (Refereed)
    Abstract [en]

    The arthropod head problem has puzzled zoologists for more than a century. The head of adult arthropods is a complex structure resulting from the modification, fusion and migration of an uncertain number of segments. In contrast, onychophorans, which are the probable sister group to the arthropods, have a rather simple head comprising three segments that are well defined during development, and give rise to the adult head with three pairs of appendages specialised for sensory and food capture/manipulative purposes. Based on the expression pattern of the anterior Hox genes labial, proboscipedia, Hox3 and Deformed, we show that the third of these onychophoran segments, bearing the slime papillae, can be correlated to the tritocerebrum, the most anterior Hox-expressing arthropod segment. This implies that both the onychophoran antennae and jaws are derived from a more anterior, Hox-free region corresponding to the proto and deutocerebrum of arthropods. Our data provide molecular support for the proposal that the onychophoran head possesses a well-developed appendage that corresponds to the anterior, apparently appendage-less region of the arthropod head.

  • 19.
    Fu, Dongjing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Zhang, Xingliang
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    The first dorsal-eyed bivalved arthropod and its significance for early arthropod evolution2014In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 136, no 1, p. 80-84Article in journal (Refereed)
    Abstract [en]

    A new bivalved arthropod Erjiecaris minusculo gen. et sp. nov. is described from the Lower Cambrian Chengjiang Lagerstatte, Yunnan, southwest China. It possesses mosaic features, such as the reduced shield that is dorsoventrally flattened, dorsally positioned eyes, ring-shaped somites and broad furcal rami. These provide an important link for assessing the evolutionary morphological gap between two distinctive Cambrian arthropod groups, crustaceanomorph and trilobite-like taxa. Thus, the new finding reported here in turn improves the understanding of the body plan of early arthropods and provides fresh insight into the evolution of the carapace/head shield and visual system.

  • 20.
    Fu, Dongjing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Zhang, Xingliang
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Liu, Wei
    Pan, Xiaoyun
    Ontogeny and dimorphism of Isoxys auritus (Arthropoda) from the Early Cambrian Chengjiang biota, South China2014In: Gondwana Research, ISSN 1342-937X, E-ISSN 1878-0571, Vol. 25, no 3, p. 975-982Article in journal (Refereed)
    Abstract [en]

    The morphology of Isoxys auritus Jiang, 1982 is reinterpreted in the light of abundant new specimens from the Early Cambrian Chengjiang biota, South China. I. auritus was a bivalved arthropod, its shield armed with two cardinal spines sub-equal in length. Two morphotypes (shield with and without ornamentation) which are of several original differences were interpreted as sexual dimorphs. 81 specimens examined here, which range between 4.8 mm and 47.0 mm, represent a successive developmental sequence. The earliest stages were characterized by short cardinal spines, large spherical eyes, a pair of elongated antennulae, and seven pairs of post-antennular appendages. The slim antennula is uniramous, consisting of nine articles, each armed with short spines. It differs from that of great appendage and lacks any grasping function. During the ontogeny, the body length increases, accompanied by addition of trunk somites and appearance of primary reticulated ornaments, and both cardinal spines become evident. In the fully grown adult, there are up to 11 pairs of post-antennular appendages, equipped with the stout endopod composed of 6 or 7 podomeres lacking endites, and a terminal claw; the paddle shaped exopod is fringed with long setae along its posterior margin. Secondary reticulation of the shield has developed inside each primary one; the cardinal spines more elongated; and the ratio of length to height of shield increases. However, the size of eye and antennula relative to the body length significantly decreases. Accordingly, intraspecific variation, including sexual dimorphs and developmental change, is evident in I. auritus. Recognizing such differences is important for detecting possible synonymies in the genus. Furthermore, the ontogenetic changes of I. auritus described here, particularly the postembryonic segment addition and possible allometric growth may also improve our understanding of development of Cambrian arthropods in Burgess-shale type preservation, especially those possessing such a large shield. (C) 2013 International Association for Gondwana Research. Published by Elsevier ay. All rights reserved.

  • 21.
    Hogvall, Mattias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Schoenauer, Anna
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    McGregor, Alistair P.
    Posnien, Nico
    Janssen, Ralf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Analysis of the Wnt gene repertoire in an onychophoran provides new insights into the evolution of segmentation2014In: EvoDevo, ISSN 2041-9139, E-ISSN 2041-9139, Vol. 5, p. 14-Article in journal (Refereed)
    Abstract [en]

    Background: The Onychophora are a probable sister group to Arthropoda, one of the most intensively studied animal phyla from a developmental perspective. Pioneering work on the fruit fly Drosophila melanogaster and subsequent investigation of other arthropods has revealed important roles for Wnt genes during many developmental processes in these animals. Results: We screened the embryonic transcriptome of the onychophoran Euperipatoides kanangrensis and found that at least 11 Wnt genes are expressed during embryogenesis. These genes represent 11 of the 13 known subfamilies of Wnt genes. Conclusions: Many onychophoran Wnt genes are expressed in segment polarity gene-like patterns, suggesting a general role for these ligands during segment regionalization, as has been described in arthropods. During early stages of development, Wnt2, Wnt4, and Wnt5 are expressed in broad multiple segment-wide domains that are reminiscent of arthropod gap and Hox gene expression patterns, which suggests an early instructive role for Wnt genes during E. kanangrensis segmentation.

  • 22.
    Israelsson, Olle
    et al.
    Uppsala University, Museums etc., Museum of Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. paleobiologi.
    Eggs and embryos in Xenoturbella (phyllum uncertain) are not ingested prey.2005In: Dev. Genes Evol., Vol. 215, p. 358-363Article in journal (Refereed)
  • 23.
    Jackson, Illiam S. C.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Intraspecific morphological variation of Agnostus pisiformis, a Cambrian Series 3 trilobite-like arthropod2017In: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, p. 467-485Article in journal (Refereed)
    Abstract [en]

    The study of evolution in a palaeontological context is chiefly the study of change in shape and form. This requires data sets that quantify morphology and morphological variation. Historically morphology has been described using discrete characters or more recently using various morphometric approaches. Elliptical Fourier analysis (EFA) is an approach to quantifying morphology that results in the production of large data sets of elliptical Fourier descriptors (EFDs), which are highly suitable to multivariate analysis. EFA is used in this paper to quantify the shape and describe the ontogeny of Agnostus pisiformis (Wahlenberg 1818: Nova Acta Regiae Societatis Scientiarum Upsaliensis 8, 1), a trilobite-like arthropod of Cambrian Series 3, from three coeval localities in Sweden. An ontogenetic difference was detected between geographically distant populations from Västergötland and Skåne in Sweden. These differences are probably the result of environmental dysoxic stress leading to increasing phenotypic variation. These findings illustrate the utility of EFA applied to the study of fossil organisms; permitting studies of such high resolution that multiple assemblages of the same species can be comparatively studied to achieve a more detailed understanding of their morphological and ontogenetic variation.

  • 24.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Investigation of endoderm marker-genes during gastrulation and gut-development in the velvet worm Euperipatoides kanangrensis2017In: Developmental Biology, ISSN 0012-1606, E-ISSN 1095-564X, Vol. 427, no 1, p. 155-164Article in journal (Refereed)
    Abstract [en]

    The ancestral state of animal gastrulation and its bearing for our understanding of bilaterian evolution still is one of the most controversially discussed topics in the field of evolutionary and developmental biology. One hypothesis, the so-called amphistomy scenario, suggests the presence of a slit-like blastopore in the last common ancestor of Bilateria. Onychophoran ontogeny at least superficially appears to support this scenario since a ventral groove clearly forms during gastrulation. The origin and nature of this groove, however, is another matter of ongoing controversy; i.e. the question of whether this structure actually represents the blastopore, or at least part of it. Recent research using genetic markers argued against the furrow representing a blastoporal structure. Here we investigate the origin of endoderm, which usually originates from the blastopore. We find conserved expression patterns of the endoderm- and gut-marker genes GATA456, GATA123, Hnf4 and fkh during gut development, and discuss the formation of the onychophoran gut in comparison with that in a range of arthropods. Despite expression of endodermal markers in and around the furrow we do not find convincing evidence that the furrow may be part of the blastopore, and thus we suggest that onychophoran development does not yield support for the amphistomy scenario.

  • 25.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Deciphering the onychophoran 'segmentation gene cascade': Gene expression reveals limited involvement of pair rule gene orthologs in segmentation, but a highly conserved segment polarity gene network2013In: Developmental Biology, ISSN 0012-1606, E-ISSN 1095-564X, Vol. 382, no 1, p. 224-234Article in journal (Refereed)
    Abstract [en]

    The hallmark of the arthropods is their segmented body, although origin of segmentation, however, is unresolved. In order to shed light on the origin of segmentation we investigated orthologs of pair rule genes (PRGs) and segment polarity genes (SPGs) in a member of the closest related sister-group to the arthropods, the onychophorans. Our gene expression data analysis suggests that most of the onychophoran PRGs do not play a role in segmentation. One possible exception is the even-skipped (eve) gene that is expressed in the posterior end of the onychophoran where new segments are likely patterned, and is also expressed in segmentation-gene typical transverse stripes in at least a number of newly formed segments. Other onychophoran PRGs such as runt (run), hairy/Hes (h/Hes) and odd-skipped (odd) do not appear to have a function in segmentation at all. Onychophoran PRGs that act low in the segmentation gene cascade in insects, however, are potentially involved in segment-patterning. Most obvious is that from the expression of the pairberry (pby) gene ortholog that is expressed in a typical SPG-pattern. Since this result suggested possible conservation of the SPG-network we further investigated SPGs (and associated factors) such as Notum in the onychophoran. We find that the expression patterns of SPGs in arthropods and the onychophoran are highly conserved, suggesting a conserved SPG-network in these two clades, and indeed also in an annelid. This may suggest that the common ancestor of lophotrochozoans and ecdysozoans was already segmented utilising the same SPG-network, or that the SPG-network was recruited independently in annelids and onychophorans/arthropods.

  • 26.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Gene expression analysis reveals that Delta/Notch signalling is not involved in onychophoran segmentation2016In: Development, Genes and Evolution, ISSN 0949-944X, E-ISSN 1432-041X, Vol. 226, no 2, p. 69-77Article in journal (Refereed)
    Abstract [en]

    Delta/Notch (Dl/N) signalling is involved in the gene regulatory network underlying the segmentation process in vertebrates and possibly also in annelids and arthropods, leading to the hypothesis that segmentation may have evolved in the last common ancestor of bilaterian animals. Because of seemingly contradicting results within the well-studied arthropods, however, the role and origin of Dl/N signalling in segmentation generally is still unclear. In this study, we investigate core components of Dl/N signalling by means of gene expression analysis in the onychophoran Euperipatoides kanangrensis, a close relative to the arthropods. We find that neither Delta or Notch nor any other investigated components of its signalling pathway are likely to be involved in segment addition in onychophorans. We instead suggest that Dl/N signalling may be involved in posterior elongation, another conserved function of these genes. We suggest further that the posterior elongation network, rather than classic Dl/N signalling, may be in the control of the highly conserved segment polarity gene network and the lower-level pair-rule gene network in onychophorans. Consequently, we believe that the pair-rule gene network and its interaction with Dl/N signalling may have evolved within the arthropod lineage and that Dl/N signalling has thus likely been recruited independently for segment addition in different phyla.

  • 27.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Gene expression suggests conserved aspects of Hox gene regulation in arthropods and provides additional support for monophyletic Myriapoda2010In: EvoDevo, ISSN 2041-9139, E-ISSN 2041-9139, Vol. 1, no 4Article in journal (Refereed)
    Abstract [en]

    Antisense transcripts of Ultrabithorax (aUbx) in the millipede Glomeris and the centipede Lithobius are expressed in patterns complementary to that of the Ubx sense transcripts. A similar complementary expression pattern has been described for non-coding RNAs (ncRNAs) of the bithoraxoid (bxd) locus in Drosophila, in which the transcription of bxd ncRNAs represses Ubx via transcriptional interference. We discuss our findings in the context of possibly conserved mechanisms of Ubx regulation in myriapods and the fly.Bicistronic transcription of Ubx and Antennapedia (Antp) has been reported previously for a myriapod and a number of crustaceans. In this paper, we show that Ubx/Antp bicistronic transcripts also occur in Glomeris and an onychophoran, suggesting further conserved mechanisms of Hox gene regulation in arthropods.Myriapod monophyly is supported by the expression of aUbx in all investigated myriapods, whereas in other arthropod classes, including the Onychophora, aUbx is not expressed. Of the two splice variants of Ubx/Antp only one could be isolated from myriapods, representing a possible further synapomorphy of the Myriapoda.

  • 28.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Damen, Wim G. M.
    Friedrich-Schiller University, Department of Genetics, Jena, Germany.
    Gene expression suggests conserved mechanisms patterning the heads of insects and myriapods2011In: Developmental Biology, ISSN 0012-1606, E-ISSN 1095-564X, Vol. 357, no 1, p. 64-72Article in journal (Refereed)
    Abstract [en]

    Segmentation, i.e. the subdivision of the body into serially homologous units, is one of the hallmarks of the arthropods. Arthropod segmentation is best understood in the fly Drosophila melanogaster. But different from the situation in most arthropods in this species all segments are formed from the early blastoderm (so called long-germ developmental mode). In most other arthropods only the anterior segments are formed in a similar way (so called short-germ developmental mode). Posterior segments are added one at a time or in pairs of two from a posterior segment addition zone. The segmentation mechanisms are not universally conserved among arthropods and only little is known about the genetic patterning of the anterior segments. Here we present the expression patterns of the insect head patterning gene orthologs hunchback (hb), orthodenticle (otd), buttonhead-like (btdl), collier (col), cap-n-collar (cnc) and crocodile (croc), and the trunk gap gene Kruppel (Kr) in the myriapod Glomeris marginata. Conserved expression of these genes in insects and a myriapod suggests that the anterior segmentation system may be conserved in at least these two classes of arthropods. This finding implies that the anterior patterning mechanism already existed in the last common ancestor of insects and myriapods.

  • 29.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Damen, Wim G. M.
    Institute for Genetics, University of Cologne, Köln, Germany.
    Prpic, Nikola-Michael
    Johann-Friedrich-Blumenbach Institut für Zoologie und Anthropologie, Abteilung für Entwicklungsbiologie, GZMB, Georg-August-Universität Göttingen, Germany.
    Evidence for Wg-independent tergite boundary formation in the millipede Glomeris marginata2008In: Development, Genes and Evolution, ISSN 0949-944X, E-ISSN 1432-041X, Vol. 218, no 7, p. 361-370Article in journal (Refereed)
    Abstract [en]

    The correlation between dorsal and ventral segmental units in diplopod myriapods is complex and disputed. Recent results with engrailed (en), hedgehog (hh), wingless (wg), and cubitus-interruptus (ci) have shown that the dorsal segments are patterned differently from the ventral segments. Ventrally, gene expression is compatible with the classical autoregulatory loop known from Drosophila to specify the parasegment boundary. In the dorsal segments, however, this Wg/Hh autoregulatory loop cannot be present because the observed gene expression patterns argue against the involvement of Wg signalling. In this paper, we present further evidence against an involvement of Wg signalling in dorsal segmentation and propose a hypothesis about how dorsal segmental boundaries may be controlled in a wg-independent way. We find that (1) the Notum gene, a modulator of the Wg gradient in Drosophila, is not expressed in the dorsal segments. (2) The H15/midline gene, a repressor of Wg action in Drosophila, is not expressed in the dorsal segments, except for future heart tissue. (3) The patched (ptc) gene, which encodes a Hh receptor, is strongly expressed in the dorsal segments, which is incompatible with Wg-Hh autoregulation. The available data suggest that anterior-posterior (AP) boundary formation in dorsal segments could instead rely on Dpp signalling rather than Wg signalling. We present a hypothesis that relies on Hh-mediated activation of Dpp signalling and optomotor-blind (omb) expression to establish the dorsal AP boundary (the future tergite boundary). The proposed mechanism is similar to the mechanism used to establish the AP boundary in Drosophila wings and ventral pleura.

  • 30.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Prpic, Nikola-Michael
    Damen, Wim
    Expression of myriapod pair rule gene orthologs2011In: EvoDevo, ISSN 2041-9139, E-ISSN 2041-9139, Vol. 2, no 5Article in journal (Refereed)
    Abstract [en]

    Background

    Segmentation is a hallmark of the arthropods; most knowledge about the molecular basis of arthropod segmentation comes from work on the fly Drosophila melanogaster. In this species a hierarchic cascade of segmentation genes subdivides the blastoderm stepwise into single segment wide regions. However, segmentation in the fly is a derived feature since all segments form virtually simultaneously. Conversely, in the vast majority of arthropods the posterior segments form one at a time from a posterior pre-segmental zone. The pair rule genes (PRGs) comprise an important level of the Drosophila segmentation gene cascade and are indeed the first genes that are expressed in typical transverse stripes in the early embryo. Information on expression and function of PRGs outside the insects, however, is scarce.

    Results

    Here we present the expression of the pair rule gene orthologs in the pill millipede Glomeris marginata (Myriapoda: Diplopoda). We find evidence that these genes are involved in segmentation and that components of the hierarchic interaction of the gene network as found in insects may be conserved. We further provide evidence that segments are formed in a single-segment periodicity rather than in pairs of two like in another myriapod, the centipede Strigamia maritima. Finally we show that decoupling of dorsal and ventral segmentation in Glomeris appears already at the level of the PRGs.

    Conclusions

    Although the pair rule gene network is partially conserved among insects and myriapods, some aspects of PRG interaction are, as suggested by expression pattern analysis, convergent, even within the Myriapoda. Conserved expression patterns of PRGs in insects and myriapods, however, may represent ancestral features involved in segmenting the arthropod ancestor.

  • 31.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Damen, Wim G. M.
    Friedrich-Schiller-University Jena, Department of Genetics, Jena, Germany .
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Expression of collier in the premandibular segment of myriapods: support for the traditional Atelocerata concept or a case of convergence?2011In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 11, p. 50-Article in journal (Refereed)
    Abstract [en]

    Background: A recent study on expression and function of the ortholog of the Drosophila collier (col) gene in various arthropods including insects, crustaceans and chelicerates suggested a de novo function of col in the development of the appendage-less intercalary segment of insects. However, this assumption was made on the background of the now widely-accepted Pancrustacea hypothesis that hexapods represent an in-group of the crustaceans. It was therefore assumed that the expression of col in myriapods would reflect the ancestral state like in crustaceans and chelicerates, i.e. absence from the premandibular/intercalary segment and hence no function in its formation. Results: We find that col in myriapods is expressed at early developmental stages in the same anterior domain in the head, the parasegment 0, as in insects. Comparable early expression of col is not present in the anterior head of an onychophoran that serves as an out-group species closely related to the arthropods. Conclusions: Our findings suggest either that i) the function of col in head development has been conserved between insects and myriapods, and that these two classes of arthropods may be closely related supporting the traditional Atelocerata (or Tracheata) hypothesis; or ii) alternatively col function could have been lost in early head development in crustaceans, or may indeed have evolved convergently in insects and myriapods.

  • 32.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Damen, Wim G. M.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Expression of pair rule gene orthologs in the blastoderm of a myriapod: evidence for pair rule-like mechanisms?2012In: BMC Developmental Biology, ISSN 1471-213X, E-ISSN 1471-213X, Vol. 12, p. 15-Article in journal (Refereed)
    Abstract [en]

    Background: A hallmark of Drosophila segmentation is the stepwise subdivision of the body into smaller and smaller units, and finally into the segments. This is achieved by the function of the well-understood segmentation gene cascade. The first molecular sign of a segmented body appears with the action of the pair rule genes, which are expressed as transversal stripes in alternating segments. Drosophila development, however, is derived, and in most other arthropods only the anterior body is patterned (almost) simultaneously from a pre-existing field of cells; posterior segments are added sequentially from a posterior segment addition zone. A long-standing question is to what extent segmentation mechanisms known from Drosophila may be conserved in short-germ arthropods. Despite the derived developmental modes, it appears more likely that conserved mechanisms can be found in anterior patterning. Results: Expression analysis of pair rule gene orthologs in the blastoderm of the pill millipede Glomeris marginata (Myriapoda: Diplopoda) suggests that these genes are generally involved in segmenting the anterior embryo. We find that the Glomeris pairberry-1 (pby-1) gene is expressed in a pair rule pattern that is also found in insects and a chelicerate, the mite Tetraynchus urticae. Other Glomeris pair rule gene orthologs are expressed in double segment wide domains in the blastoderm, which at subsequent stages split into two stripes in adjacent segments. Conclusions: The expression patterns of the millipede pair rule gene orthologs resemble pair rule patterning in Drosophila and other insects, and thus represent evidence for the presence of an ancestral pair rule-like mechanism in myriapods. We discuss the possibilities that blastoderm patterning may be conserved in long-germ and short-germ arthropods, and that a posterior double segmental mechanism may be present in short-germ arthropods.

  • 33.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Eriksson, Bo Joakim
    Department of Zoology, University Museum of Zoology, Cambridge,UK.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Akam, Michael
    Department of Zoology, University Museum of Zoology, Cambridge, UK.
    Prpic, Nikola-Michael
    Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Georg-August-Universität, Abteilung Entwicklungsbiologie, GZMB, Göttingen, Germany.
    Gene expression patterns in an onychophoran reveal that regionalization predates limb segmentation in pan-arthropods2010In: Evolution & Development, ISSN 1520-541X, E-ISSN 1525-142X, Vol. 12, no 4, p. 363-372Article in journal (Refereed)
    Abstract [en]

    In arthropods, such as Drosophila melanogaster, the leg gap genes homothorax (hth), extradenticle (exd), dachshund (dac), and Distal-less (Dll) regionalize the legs in order to facilitate the subsequent segmentation of the legs. We have isolated homologs of all four leg gap genes from the onychophoran Euperipatoides kanangrensis and have studied their expression. We show that leg regionalization takes place in the legs of onychophorans even though they represent simple and nonsegmented appendages. This implies that leg regionalization evolved for a different function and was only later co-opted for a role in leg segmentation. We also show that the leg gap gene patterns in onychophorans (especially of hth and exd) are similar to the patterns in crustaceans and insects, suggesting that this is the plesiomorphic state in arthropods. The reversed hth and exd patterns in chelicerates and myriapods are therefore an apomorphy for this group, the Myriochelata, lending support to the Myriochelata and Tetraconata clades in arthropod phylogeny.

  • 34.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Eriksson, Bo Joakim
    Tait, Noel N.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Onychophoran Hox genes and the evolution of arthropod Hox gene expression2014In: Frontiers in Zoology, ISSN 1742-9994, E-ISSN 1742-9994, Vol. 11, p. 22-Article in journal (Refereed)
    Abstract [en]

    Introduction: Onychophora is a relatively small phylum within Ecdysozoa, and is considered to be the sister group to Arthropoda. Compared to the arthropods, that have radiated into countless divergent forms, the onychophoran body plan is overall comparably simple and does not display much in-phylum variation. An important component of arthropod morphological diversity consists of variation of tagmosis, i.e. the grouping of segments into functional units (tagmata), and this in turn is correlated with differences in expression patterns of the Hox genes. How these genes are expressed in the simpler onychophorans, the subject of this paper, would therefore be of interest in understanding their subsequent evolution in the arthropods, especially if an argument can be made for the onychophoran system broadly reflecting the ancestral state in the arthropods. Results: The sequences and embryonic expression patterns of the complete set of ten Hox genes of an onychophoran (Euperipatoides kanangrensis) are described for the first time. We find that they are all expressed in characteristic patterns that suggest a function as classical Hox genes. The onychophoran Hox genes obey spatial colinearity, and with the exception of Ultrabithorax (Ubx), they all have different and distinct anterior expression borders. Notably, Ubx transcripts form a posterior to anterior gradient in the onychophoran trunk. Expression of all onychophoran Hox genes extends continuously from their anterior border to the rear end of the embryo. Conclusions: The spatial expression pattern of the onychophoran Hox genes may contribute to a combinatorial Hox code that is involved in giving each segment its identity. This patterning of segments in the uniform trunk, however, apparently predates the evolution of distinct segmental differences in external morphology seen in arthropods. The gradient-like expression of Ubx may give posterior segments their specific identity, even though they otherwise express the same set of Hox genes. We suggest that the confined domains of Hox gene expression seen in arthropods evolved from an ancestral onychophoran-like Hox gene pattern. Reconstruction of the ancestral arthropod Hox pattern and comparison with the patterns in the different arthropod classes reveals phylogenetic support for Mandibulata and Tetraconata, but not Myriochelata and Atelocerata.

  • 35.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Jorgensen, Mette
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Lagebro, Linda
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Fate and nature of the onychophoran mouth-anus furrow and its contribution to the blastopore2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1805, article id 20142628Article in journal (Refereed)
    Abstract [en]

    The ancestral states of bilaterian development, and which living groups have conserved them the most, has been a controversial topic in biology for well over a hundred years. In recent years, the idea that gastrulation primitively proceeded via the formation of a slit-like blastopore that then evolved into either protostomy or deuterostomy has gained renewed attention and some molecular developmental support. One of the key pieces of evidence for this 'amphistomy' theory comes from the onychophorans, which form a clear ventral groove during gastrulation. The interpretation of this structure has, however, proved problematic. Based on expression patterns of forkhead (fkh), caudal (cad), brachyury (bra) and wingless (wg/Wnt1), we show that this groove does not correspond to the blastopore, even though both the mouth and anus later develop from it. Rather, the posterior pit appears to be the blastopore; the posterior of the groove later fuses with it to form the definitive anus. Onychophoran development therefore represents a case of 'concealed' deuterostomy. The new data from the onychophorans thus remove one of the key pieces of evidence for the amphistomy theory. Rather, in line with other recent results, it suggests that ancestral bilaterian development was deuterostomic.

  • 36.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Jörgensen, Mette
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Prpic, Nikola-Michael
    Budd, Graham
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Aspects of dorso-ventral and proximo-distal limb patterning in onychophorans2015In: Evolution & Development, ISSN 1520-541X, E-ISSN 1525-142X, Vol. 17, no 1, p. 21-33Article in journal (Refereed)
    Abstract [en]

    Onychophorans (velvet worms) are closely related to the arthropods, but their limb morphology represents a stage before arthropodization (i.e., the segmentation of the limbs). We investigated the expression of onychophoran homologs of genes that are involved in dorso-ventral (DV) and proximo-distal (PD) limb patterning in arthropods. We find that the two onychophoran optomotor-blind (omb) genes, omb-1 and omb-2, are both expressed in conserved patterns in the dorsal ectoderm of the limbs, including the onychophoran antennae (the frontal appendages). Surprisingly, the expression of decapentaplegic (dpp), which acts upstream of omb in Drosophila, is partially reversed in onychophoran limbs compared to its expression in arthropods. A conserved feature of dpp expression in arthropods and onychophorans, however, is the prominent expression of dpp in the tips of developing limbs, which, therefore, may represent the ancestral pattern. The expression patterns of wingless (wg) and H15 are very diverged in onychophorans. The wg gene is only expressed in the limb tips and the single H15 gene is expressed in a few dorsal limb cells, but not on the ventral side. The expression of wg and dpp at the limb tips is one of the three possible alternatives predicted by the topology model of arthropod limb patterning and is, thus, compatible with a conserved function of wg and dpp in the patterning of the PD axis. On the other hand, DV limb gene expression is less conserved, and the specification of ventral fate appears to involve neither wg nor H15 expression.

  • 37.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Le Gouar, Martine
    Pechmann, Matthias
    Poulin, Francis
    Bolognesi, Renata
    Schwager, Evelyn E.
    Hopfen, Corinna
    Colbourne, John K.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Brown, Susan J.
    Prpic, Nikola-Michael
    Kosiol, Carolin
    Vervoort, Michel
    Damen, Wim G. M.
    Balavoine, Guillaume
    McGregor, Alistair P.
    Conservation, loss, and redeployment of Wnt ligands in protostomes: implications for understanding the evolution of segment formation2010In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 10, p. 374-, article id 374Article in journal (Refereed)
    Abstract [en]

    Background: The Wnt genes encode secreted glycoprotein ligands that regulate a wide range of developmental processes, including axis elongation and segmentation. There are thirteen subfamilies of Wnt genes in metazoans and this gene diversity appeared early in animal evolution. The loss of Wnt subfamilies appears to be common in insects, but little is known about the Wnt repertoire in other arthropods, and moreover the expression and function of these genes have only been investigated in a few protostomes outside the relatively Wnt-poor model species Drosophila melanogaster and Caenorhabditis elegans. To investigate the evolution of this important gene family more broadly in protostomes, we surveyed the Wnt gene diversity in the crustacean Daphnia pulex, the chelicerates Ixodes scapularis and Achaearanea tepidariorum, the myriapod Glomeris marginata and the annelid Platynereis dumerilii. We also characterised Wnt gene expression in the latter three species, and further investigated expression of these genes in the beetle Tribolium castaneum. Results: We found that Daphnia and Platynereis both contain twelve Wnt subfamilies demonstrating that the common ancestors of arthropods, ecdysozoans and protostomes possessed all members of all Wnt subfamilies except Wnt3. Furthermore, although there is striking loss of Wnt genes in insects, other arthropods have maintained greater Wnt gene diversity. The expression of many Wnt genes overlap in segmentally reiterated patterns and in the segment addition zone, and while these patterns can be relatively conserved among arthropods and the annelid, there have also been changes in the expression of some Wnt genes in the course of protostome evolution. Nevertheless, our results strongly support the parasegment as the primary segmental unit in arthropods, and suggest further similarities between segmental and parasegmental regulation by Wnt genes in annelids and arthropods respectively. Conclusions: Despite frequent losses of Wnt gene subfamilies in lineages such as insects, nematodes and leeches, most protostomes have probably maintained much of their ancestral repertoire of twelve Wnt genes. The maintenance of a large set of these ligands could be in part due to their combinatorial activity in various tissues.

  • 38.
    Janssen, Ralf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Wennberg, Sofia A.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    The hatching larva of the priapulid worm Halicryptus spinulosus2009In: Frontiers in Zoology, ISSN 1742-9994, E-ISSN 1742-9994, Vol. 6, no 8Article in journal (Refereed)
    Abstract [en]

    Despite their increasing evolutionary importance, basic knowledge about the priapulid worms remains limited. In particular, priapulid development has only been partially documented. Following previous description of hatching and the earliest larval stages of Priapulus caudatus, we here describe the hatching larva of Halicryptus spinulosus. Comparison of the P. caudatus and the H. spinulosus hatching larvae allows us to attempt to reconstruct the ground pattern of priapulid development. These findings may further help unravelling the phylogenetic position of the Priapulida within the Scalidophora and hence contribute to the elucidation of the nature of the ecdysozoan ancestor.

  • 39.
    Kear, Benjamin P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    New perspectives on ancient marine reptiles2014In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 151, no 1, p. 5-6Article in journal (Other academic)
    Abstract [en]

    Amniotes first invaded saline lagoons and coastal seaways towards the end of the Palaeozoic (Early Permian, similar to 280 Ma: Pineiro et al. 2012), but by the dawn of the Mesozoic (Early-Middle Triassic, similar to 250-235 Ma: Rieppel, 2002; McGowan & Motani, 2003) they had achieved a diversity of specialized body-forms requisite for an obligate oceanic lifestyle. Such an explosive ecomorphological radiation paved the way for amniote dominance of large-bodied aquatic carnivore/omnivore niches over the next 185 Ma, with some lineages (e.g. dyrosaurid crocodylomorphs and bothremydid turtles: Gaffney, Tong & Meylan, 2006; Barbosa, Kellner & Sales Viana, 2008) even persisting on into the Palaeogene (until similar to 50 Ma), and diversifying (i.e. chelonioid sea turtles: Hirayama, 1997) alongside emergent marine mammals through the Neogene (from similar to 23 Ma) and up until today.

  • 40.
    Lagebro, Linda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Gueriau, Pierre
    Hegna, Thomas A
    Rabet, Nicolas
    Butler, Aodhan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    The oldest notostracan (Upper Devonian Strud locality, Belgium)2015In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 58, no 3, p. 497-509Article in journal (Refereed)
    Abstract [en]

    A new notostracan crustacean, Strudops goldenbergi gen. et sp. nov., is described from the well-preserved terrestrial arthropod fauna of the Upper Devonian of Strud, Belgium. The fossil notostracan bears a close resemblance to modern notostracans in possessing a large, simple head shield covering almost half of the whole body, a set of phyllopodous thoracic appendages and a legless posterior abdomen with a telson bearing a caudal furca. The differentiation and relative size of mouthparts and limbs suggest that these specimens are all adults. The notostracans described herein are the earliest clear members of the total group Notostraca.

  • 41. Martin-Duran, Jose M.
    et al.
    Janssen, Ralf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Wennberg, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Hejnol, Andreas
    Deuterostomic Development in the Protostome Priapulus caudatus2012In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 22, no 22, p. 2161-2166Article in journal (Refereed)
    Abstract [en]

    The fate of the blastopore during development in the bilaterian ancestor is currently not well understood. In deuterostomes, the blastopore forms the anus, but its fate in protostome groups is variable [1]. This variability, combined with an absence of information from key taxa, hampers the reconstruction of the ancestral developmental mode of the Protostomia and the Bilateria. The blastopore fate of the bilaterian ancestor plays a crucial role in understanding the transition from radial to bilateral symmetric organisms [2, 3]. Priapulids have a conservative morphology, an abundant Cambrian fossil record, and a phylogenetic position that make them a key group in understanding protostome evolution [4, 5]. Here, we characterize gastrulation and the embryonic expression of genes involved in bilaterian foregut and hindgut patterning in Priapulus caudatus. We show that the blastopore gives rise to the anus at the vegetal pole and that the hindgut markers brachyury and caudal are expressed in the blastopore and anus, whereas the foregut markers foxA and goosecoid are expressed in the mouth in the animal hemisphere. Thereby, gastrulation in the conservatively evolving protostome P. caudatus follows strictly a deuterostomic pattern. These results are more compatible with a deuterostomic rather than protostomic (blastopore forms the mouth) or amphistomic (mouth and anus are formed simultaneously) mode of development in the last common bilaterian ancestor.

  • 42.
    Moczydłowska, Małgorzata
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Agić, Heda
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Ecdysozoan-like sclerites among Ediacaran microfossils2015In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 152, no 6, p. 1145-1148Article in journal (Refereed)
    Abstract [en]

    We report the occurrence of organically preserved microfossils from the subsurface Ediacaran strata overlying the East European Platform in Poland, in the form of sclerites and cuticle fragments of larger organisms. They are morphologically similar to those known from Cambrian strata and associated with various metazoan fossils of recognized phyla. The Ediacaran age of the microfossils is evident from the stratigraphic position below the base of the Cambrian System and above the isotopically dated tuff layers at c. 551±4Ma. Within this strata interval, other characteristic Ediacaran microorganisms co-occur such as cyanobacteria, vendotaenids, microalgae, Ceratophyton,Valkyria and macroscopic annelidan Sabellidites. The recent contributions of organic sclerites in revealing the scope of the Cambrian explosion are therefore also potentially extendable back to the Ediacaran Period when animals first appear in the fossil record.

  • 43. Ortega-Hernandez, J.
    et al.
    Janssen, Ralf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Origin and Evolution of the Panarthropod Head - a Deep Time Perspective2017In: Integrative and Comparative Biology, ISSN 1540-7063, E-ISSN 1557-7023, Vol. 57, p. E369-E369Article in journal (Other academic)
  • 44.
    Ortega-Hernandez, Javier
    et al.
    Univ Cambridge.
    Janssen, Ralf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Origin and evolution of the panarthropod head: A palaeobiological and developmental perspective2017In: Arthropod structure & development, ISSN 1467-8039, E-ISSN 1873-5495, Vol. 46, no 3, p. 354-379Article, review/survey (Refereed)
    Abstract [en]

    The panarthropod head represents a complex body region that has evolved through the integration and functional specialization of the anterior appendage-bearing segments. Advances in the developmental biology of diverse extant organisms have led to a substantial clarity regarding the relationships of segmental homology between Onychophora (velvet worms), Tardigrada (water bears), and Euarthropoda (e.g. arachnids, myriapods, crustaceans, hexapods). The improved understanding of the segmental organization in panarthropods offers a novel perspective for interpreting the ubiquitous Cambrian fossil record of these successful animals. A combined palaeobiological and developmental approach to the study of the panarthropod head through deep time leads us to propose a consensus hypothesis for the intricate evolutionary history of this important tagma. The contribution of exceptionally preserved brains in Cambrian fossils together with the recognition of segmentally informative morphological characters illuminate the polarity for major anatomical features. The euarthropod stem-lineage provides a detailed view of the step-wise acquisition of critical characters, including the origin of a multiappendicular head formed by the fusion of several segments, and the transformation of the ancestral protocerebral limb pair into the labrum, following the postero-ventral migration of the mouth opening. Stem-group onychophorans demonstrate an independent ventral migration of the mouth and development of a multisegmented head, as well as the differentiation of the deutocerebral limbs as expressed in extant representatives. The anterior organization of crown-group Tardigrada retains several ancestral features, such as an anterior-facing mouth and one-segmented head. The proposed model aims to clarify contentious issues on the evolution of the panarthropod head, and lays the foundation from which to further address this complex subject in the future.

  • 45.
    Skovsted, Christian B.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Brock, Glenn A.
    Centre for Ecostratigraphy and Palaeobiology, Department of Earth and Planetary Sciences, Macquarie University, Australia .
    Paterson, John R.
    Division of Earth Sciences, School of Environmental and Rural Science, University of New England, Armidale Australia .
    Holmer, Lars E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    The scleritome of Eccentrotheca from the Lower Cambrian of South Australia: Lophophorate affinities and implications for tommotiid phylogeny2008In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 36, no 2, p. 171-174Article in journal (Refereed)
    Abstract [en]

    The first partially articulated scleritome of a tommotiid, Eccentrotheca sp., is described from the Lower Cambrian of South Australia. The Eccentrotheca scleritome consists of individual sclerites; fused in a spiral arrangement, forming a tapering tube-shaped skeleton with an inclined apical aperture and a circular to subcircular cross section. Traditionally, tommotiid sclerites have been assumed to form a dorsal armor of imbricating phosphatic plates in slug-like bilaterians, analogous to the calcareous sclerites of halkieriids. The structure of the Eceentrotheca scleritome is here reinterpreted as a tube composed of independent, irregularly shaped sclerites growing by basal-marginal accretion that were successively fused to form a rigid, protective tubular structure. The asymmetrical shape and sometimes acute inclination of the apical aperture suggests that the apical part of the scleritome was cemented to a hard surface via a basal disc, from which it projected vertically. Rather than being a vagrant member of the benthos, Eccentrotheca most likely represented a sessile, vermiform filter feeder. The new data suggest that the affinities of Eccentrotheca, and possibly some other problematic tommotiids, lie with the lophophorates (i.e., the phoronids and brachiopods), a clade that also possesses a phosphatic shell chemistry and a sessile life habit.

  • 46.
    Skovsted, Christian
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Brock, Glenn A.
    Paterson, John R.
    Holmer, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Eccentrotheca from the Lower Cambrian of South Australia – the first known tommotiid scleritome and its biological implications2007In: 51st Palaeontological Association Annual Meeting: Programme with Abstracts, 2007, p. 55-Conference paper (Other scientific)
    Abstract [en]

    The discovery of the first partially articulated scleritome of a tommotiid, Eccentrotheca sp. from the Lower Cambrian of the Flinders Ranges in South Australia necessitates a complete revision of the gross morphology and biological function of the problematic tommotiids. The scleritome of Eccentrotheca is an expanding tubular structure with a circular cross-section that was formed by the episodic merging of individual cone-shaped sclerites. The basal region of the tube has an open aperture, the morphology and inclination of which varies considerably. Growth patterns in the apical region indicate that the aperture housed structures that helped anchor the tube to a hard substrate. The Eccentrotheca animal is consequently reinterpreted as a sessile, epibiotic filter-feeder. This model contrasts sharply to all previously published models of tommotiid animals, which almost without exception envisages a slug-like animal with a dorsal cover of imbricating sclerites (modelled after the scleritome of the coeval halkieriid animal). Tommotiids have been suggested to fall within the stem group of the Brachiopoda, mainly based on the organophosphatic composition and brachiopod-like shell structure of some tommotiids. The sessile, filter-feeding lifestyle inferred from the scleritome of Eccentrotheca appears to strengthen the lophophorate hypothesis of tommotiid relationships, although the tubicous habit of the scleritome is more reminiscent of phoronids than brachiopods.

  • 47.
    Slater, Ben
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Willman, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Peel, John Stuart
    Uppsala University, Music and Museums, Museum of Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Widespread preservation of small carbonaceous fossils (SCFs) in the early Cambrian of North Greenland2018In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 46, no 2, p. 107-110Article in journal (Refereed)
    Abstract [en]

    The early Cambrian (ca. 518 Ma) Sirius Passet Lagerstätte of North Greenland is one of the most celebrated sites bearing fossils of soft-bodied organisms, and provides key insights into the Cambrian explosion of animal life. Unlike the younger Burgess Shale (508 Ma), the Sirius Passet biota does not preserve original carbonaceous material because of its history of metamorphic heating. Nearby sediments from within the same formation, however, have escaped the worst effects of thermal alteration. We report an entirely new diversity of metazoan remains preserved in a Burgess Shale–type fashion from sediments throughout the Buen Formation, in the form of small carbonaceous fossils (SCFs). The assemblages include the oldest known pterobranch hemichordates, diverse cuticular spines of scalidophoran worms, demineralized trilobite cuticle, bivalved arthropods (Spinospitella-like and Isoxys-like forms), protoconodonts, and a variety of less phylogenetically constrained metazoan and protistan forms. Together these SCFs capture exceptional microanatomical details of early Cambrian metazoans and offer new insights into taphonomic pathways at Sirius Passet and the nature of Burgess Shale–type preservation.

  • 48.
    Sookias, Roland B.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Kear, Benjamin P.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Mesozoic fossil sustainability: synoptic case studies of resource management2013In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 135, no 1, p. 131-143Article in journal (Refereed)
    Abstract [en]

    Fossils are a non-renewable natural resource that is not only important to science but also has immense value for education, tourism and commercial trade. Although the importance of sustainably managing exceptionally rich fossil localities is widely acknowledged, it is not universal and irreplaceable scientific information and socioeconomic benefits are being lost. This study provides an overview of the economic, social and environmental factors affecting 10 contrasting fossil localities in Germany, China, Brazil, the United Kingdom, Canada, Australia and France that are significant for preserving the remains of Mesozoic vertebrates; these are amongst the most spectacular extinct animals and readily capture the public imagination. A discussion in the context of sustainable development is carried out. Non-extractive and scientific/educational (e.g. museums, geotourism) usage of fossil deposits are fully sustainable and benefit communities both economically and socially. Conversely, extractive uses (commercial collecting, quarrying) effect resource depletion but can be managed through scientific involvement, regulation and reinvestment of profits. Ultimately, implementation of an integrated approach embracing both profitable development and appropriate protection measures may ensure optimal usage of fossils for the future.

  • 49. Stein, Martin
    et al.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Peel, John Stuart
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Harper, David A. T.
    Arthroaspis n. gen., a common element of the Sirius Passet Lagerstatte (Cambrian, North Greenland), sheds light on trilobite ancestry2013In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 13, p. 99-Article in journal (Refereed)
    Abstract [en]

    Background: Exceptionally preserved Palaeozoic faunas have yielded a plethora of trilobite-like arthropods, often referred to as lamellipedians. Among these, Artiopoda is supposed to contain taxa united by a distinctive appendage structure. This includes several well supported groups, Helmetiida, Nektaspida, and Trilobita, as well as a number of problematic taxa. Interrelationships remain unclear, and the position of the lamellipedian arthropods as a whole also remains the subject of debate. Results: Arthroaspis bergstroemi n. gen. n. sp., a new arthropod from the early Cambrian Sirius Passet Lagerstatte of North Greenland shows a striking combination of both dorsal and ventral characters of Helmetiida, Nektaspida, and Trilobita. Cladistic analysis with a broad taxon sampling of predominantly early Palaeozoic arthropods yields a monophyletic Lamellipedia as sister taxon to the Crustacea or Tetraconata. Artiopoda is resolved as paraphyletic, giving rise to the Marrellomorpha. Within Lamellipedia, a clade of pygidium bearing taxa is resolved that can be shown to have a broadly helmetiid-like tergite morphology in its ground pattern. This morphology is plesiomorphically retained in Helmetiida and in Arthroaspis, which falls basally into a clade containing Trilobita. The trilobite appendages, though similar to those of other lamellipedians in gross morphology, have a unique outward rotation of the anterior trunk appendages, resulting in a 'hard wired' lateral splay, different to that observed in other Lamellipedia. Conclusions: The combination of helmetiid, trilobite, and nektaspid characters in Arthroaspis gives important hints concerning character polarisation within the trilobite-like arthropods. The distinctive tergite morphology of trilobites, with its sophisticated articulating devices, is derived from flanged edge-to-edge articulating tergites forming a shield similar to the helmetiids, previously considered autapomorphic for that group. The stereotypical lateral splay of the appendages of lamellipedians is a homoplastic character shown to be achieved by several groups independently.

  • 50.
    Streng, Michael
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Geyer, Gerd
    Budd, Graham
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    A bone bed without bones: the Middle Cambrian 'fragment limestone' of Scania, Sweden2006Conference paper (Refereed)
    Abstract [en]

    The Middle Cambrian 'fragment limestone' of southeastern Scania (S. Sweden) is a greenish-gray wacke- to packstone layer that varies in thickness from 2 to 20 cm, overlying the Gislöv Formation (sensu stricto) with an erosive contact. It is extremely rich and diverse in small phosphatic-shelled fossils: 16 different taxa have been identified thus far, among which the phosphatic shelled brachiopods are the most common (seven taxa). Other faunal elements are paraconodonts (two taxa), palaeoscolecids (two taxa), phosphatocopids (at least two taxa), Microdyction sp., Lapworthella sp., and Hyolithellus sp., and undeterminable trilobite hash. Petrographic features of the fragment limestone such as phosphorite nodules, pyrite and authigenic glauconite, scattered quartz grains, the high content of phosphatic-shelled organisms, as well as signs of stratigraphic mixture (reworking), presence of intraclasts, and an erosive sole indicate a genesis similar to classical bone beds such as the Muschelkalk Grenzbonebed of South Germany. The fragment limestone is considered here to be a condensation deposit (Konzentratlagerstätte) in which phosphatic-shelled organisms have been enriched by long-term sedimentary reworking and winnowing of finer material.

12 1 - 50 of 57
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