A5068768940- Paleontology and Stratigraphy of Fossils
- Marine Biology and Ecology Research
- Evolution and Paleontology Studies
- Tardigrade Biology and Ecology
- Geology and Paleoclimatology Research
- Protist diversity and phylogeny
- Paleontology and Evolutionary Biology
- Marine Invertebrate Physiology and Ecology
- Developmental Biology and Gene Regulation
- Biocrusts and Microbial Ecology
- Cephalopods and Marine Biology
- Genetic diversity and population structure
- Fossil Insects in Amber
- Insect and Arachnid Ecology and Behavior
- Marine Ecology and Invasive Species
- Morphological variations and asymmetry
- Genomics and Phylogenetic Studies
- Marine and environmental studies
- Neurobiology and Insect Physiology Research
- Geological and Geophysical Studies
- Geological formations and processes
- Mollusks and Parasites Studies
- Marine and coastal plant biology
- Polar Research and Ecology
- Parasite Biology and Host Interactions
Uppsala University
2016-2025
British Antarctic Survey
2012-2016
University of Cambridge
1992-2016
Earth and Space Research
2014-2016
Durham University
2009-2016
Polar Scientific
2016
University of Glasgow
2016
Google (United States)
2015
University College London
2014
Peking University
2013
SUMMARY Segmentation as an attribute of organisms is being increasingly discussed in the recent literature because (1) new phylogenies suggest that classically considered to be segmented may lie separate clades; (2) molecular basis segmental development has been much studied; (3) various theories bilaterian origins place weight on segmentation a primitive character; (4) there stress importance modularity evolutionary topic. However, definition and extent are highly ambiguous usually...
Opabinia regalis Walcott is an enigmatic fossil from the Middle Cambrian Burgess Shale of uncertain affinities. Recent suggestions place it in a clade with Anomalocaris Whiteaves and Kerygmachela Budd Greenlandic Sirius Passet Fauna; these taxa have been interpreted as ‘lobopods’. Consideration available specimens demonstrates that reflective extensions axial region, previously thought to be either gut diverticula or musculature, can accommodated neither trunk nor lateral lobes arise it....
Abstract 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 in metazoans this gene diversity appeared early animal evolution. loss appears to be common insects, but little is known about the repertoire other arthropods, moreover expression function these have only been investigated few protostomes outside relatively -poor model species Drosophila...
As the largest predators of Cambrian seas, anomalocaridids had an important impact in structuring first complex marine animal communities, but many aspects anomalocaridid morphology, diversity, ecology, and affinity remain unclear owing to a paucity specimens. Here we describe Hurdia, based on several hundred specimens from Burgess Shale Canada. Hurdia possesses general body architecture similar those Anomalocaris Laggania, including presence exceptionally well-preserved gills, differs by...
Abstract The neuroectoderm of the Euperipatoides kanangrensis embryo becomes distinguishable during germ band formation when antennal segment is evident externally. During later stages development, proliferates extensively and, at anterior part head, newly–formed neuron precursor cells occupy most volume. antenna forms from dorsolateral side somite. has no its own onset formation, but instead, neurons migrate out to appendage nearby region developing brain. When tract formed it positioned...
Abstract Specimens of Kerygmachela kierkegaardi Budd are described, from the Lower Cambrian Sirius Passet fauna N Greenland. The cephalic region is characterised by a pair stout unsegmented appendages each bearing long spinose processes, and an anterior mouth. trunk shows alternating rows tubercles transverse annulations along axis, to which attached 11 pairs gill-bearing lateral lobes lobopodous limbs. caudal small, bears two tail spines. There some evidence for circular musculature...
The ancestor of the arthropods is widely thought to have possessed a hydrostatic skeleton surrounded by peripheral longitudinal and circular musculature, as exhibited extant onychophorans. However, transition lever-style musculature system with an articulating exoskeleton poses difficult problem in functional evolution: did or evolve first, how? Here, reference Lower Cambrian stem-group arthropod Pambdelurion, resolved terms preadaptation degeneracy without recourse saltational notions. taxa...
Chen et al . ([ 1 ][1]) reported coelomate bilaterians from the ∼600-million-year-old Doushantuo phosphorites in southern China. Such a find might meet some common expectations of small, simple emerging after worldwide glaciations Neoproterozoic. The interpretation is not
Research Article| February 01, 2008 The scleritome of Eccentrotheca from the Lower Cambrian South Australia: Lophophorate affinities and implications for tommotiid phylogeny Christian B. Skovsted; Skovsted 1Department Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, SE-752 36 Uppsala, Sweden Search other works by this author on: GSW Google Scholar Glenn A. Brock; Brock 2Centre Ecostratigraphy Department Planetary Macquarie NSW 2109, Australia John R. Paterson; Paterson...
Abstract: The complex history of description the anomalocaridids has partly been caused by fragmentary nature these fossils. Frontal appendages and mouth parts are more readily preserved than whole-body assemblages, so earliest work on animals examined structures in isolation. After several decades research, disarticulated elements were assembled together to reconstruct anomalocaridid body plan, a total three Burgess Shale genera, Anomalocaris, Laggania Hurdia, described full. Here we...
Simulation studies of the early origins modern phyla in fossil record, and rapid diversification that led to them, show these are inevitable outcomes long-lasting radiations. Recent advances Cambrian stratigraphy have revealed a more precise picture bilaterian radiation taking place during earliest Terreneuvian Series, although several ambiguities remain. The period is dominated by various tubes moderately diverse trace with classical 'Tommotian' small shelly biota beginning appear some...
In Cambrian fossil Lagerstätten like the Burgess Shale, exceptionally preserved arthropods constitute a large part of taxonomic diversity, providing opportunities to study early evolution this phylum in detail. The anomalocaridids, presumed pelagic predators, are particularly relevant owing their unique combination morphological characters and basal position arthropod stem lineage. Although isolated elements fragmented specimens were first discovered over 100 years ago, subsequent findings...
Exceptionally preserved fossils provide major insights into the evolutionary history of life. Microbial activity is thought to play a pivotal role in both decay organisms and preservation soft tissue fossil record, though this has been subject very little experimental investigation. To remedy this, we undertook an study brine shrimp Artemia, examining roles autolysis, microbial activity, oxygen diffusion reducing conditions. Our findings indicate that endogenous gut bacteria are main factor...
Survivorship biases can generate remarkable apparent rate heterogeneities through time in otherwise homogeneous birth‐death models of phylogenies. They are a potential explanation for many striking patterns seen the fossil record and molecular One such bias is "push past": clades that survived substantial length likely to have experienced high early diversification. This creates illusion secular slow‐down is, rather, reversion mean. An extra effect increasing rates lineage generation also...