Zoology: War of the Worms.
Current Biology 26(8):R335 (2016)
The phylogenetic affinities of Xenacoelomorpha - the phylum comprising Xenoturbella bocki and acoelomorph worms - are debated. Two recent studies conclude they represent the earliest branching bilaterally symmetrical animals, but additional tests may be needed to confirm this notion.
Regulatory circuit rewiring and functional divergence of the duplicate admp genes in dorsoventral axial patterning.
Developmental Biology 410(1):108 (2016)
The spatially opposed expression of Antidorsalizing morphogenetic protein (Admp) and BMP signals controls dorsoventral (DV) polarity across Bilateria and hence represents an ancient regulatory circuit. Here, we show that in addition to the conserved admp1 that constitutes the ancient circuit, a ...
Evolution: A sisterly dispute.
Nature 529(7586):286 (2016)
Light-sheet microscopy for everyone? Experience of building an OpenSPIM to study flatworm development.
BMC Developmental Biology 16(1):22 (2016)
Selective plane illumination microscopy (SPIM a type of light-sheet microscopy) involves focusing a thin sheet of laser light through a specimen at right angles to the objective lens. As only the thin section of the specimen at the focal plane of the lens is illuminated, out of focus light is na...
Uncertainty in the Timing of Origin of Animals and the Limits of Precision in Molecular Timescales.
Current Biology 25(22):2939 (2015)
The timing of divergences among metazoan lineages is integral to understanding the processes of animal evolution, placing the biological events of species divergences into the correct geological timeframe. Recent fossil discoveries and molecular clock dating studies have suggested a divergence o...
Phylogenomic Insights into Animal Evolution.
Current Biology 25(19):R876 (2015)
Animals make up only a small fraction of the eukaryotic tree of life, yet, from our vantage point as members of the animal kingdom, the evolution of the bewildering diversity of animal forms is endlessly fascinating. In the century following the publication of Darwin's Origin of Species, hypothe...
A transcriptomic-phylogenomic analysis of the evolutionary relationships of flatworms.
Current Biology 25(10):1347 (2015)
The interrelationships of the flatworms (phylum Platyhelminthes) are poorly resolved despite decades of morphological and molecular phylogenetic studies. The earliest-branching clades (Catenulida, Macrostomorpha, and Polycladida) share spiral cleavage and entolecithal eggs with other lophotrocho...
The complete mitochondrial genome of the geophilomorph centipede Strigamia maritima.
PLoS ONE 10(3):e0121369 (2015)
Strigamia maritima (Myriapoda; Chilopoda) is a species from the soil-living order of geophilomorph centipedes. The Geophilomorpha is the most speciose order of centipedes with over a 1000 species described. They are notable for their large number of appendage bearing segments and are being used ...
Molecular developmental evidence for a subcoxal origin of pleurites in insects and identity of the subcoxa in the gnathal appendages.
Scientific reports 5:15757 (2015)
Pleurites are chitinous plates in the body wall of insects and myriapods. They are believed to be an adaptation to locomotion on land but their developmental and evolutionary origins are unclear. A widely endorsed explanation for their origin is through toughening pre-existing parts of the body ...
The first myriapod genome sequence reveals conservative arthropod gene content and genome organisation in the centipede Strigamia maritima.
PLoS Biology 12(11):e1002005 (2014)
Myriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to other arthropods. All members of the class are terrestrial, but they attained terrestriality independently of insects. Myriapoda is the only arthropod class not represented by a sequenced genome. We pre...
Phylogenomic analysis of echinoderm class relationships supports Asterozoa.
Proceedings of the Royal Society B: Biological ... 281(1786) (2014)
While some aspects of the phylogeny of the five living echinoderm classes are clear, the position of the ophiuroids (brittlestars) relative to asteroids (starfish), echinoids (sea urchins) and holothurians (sea cucumbers) is controversial. Ophiuroids have a pluteus-type larva in common with echi...
Cellular dynamics during regeneration of the flatworm Monocelis sp. (Proseriata, Platyhelminthes).
EvoDevo 5:37 (2014)
Proseriates (Proseriata, Platyhelminthes) are free-living, mostly marine, flatworms measuring at most a few millimetres. In common with many flatworms, they are known to be capable of regeneration; however, few studies have been done on the details of regeneration in proseriates, and none cover ...
Evolution. The animal tree of life.
Science 339(6121):764 (2013)
Xenoturbella bocki exhibits direct development with similarities to Acoelomorpha.
Nature Communications 4:1537 (2013)
Xenoturbella bocki, a marine animal with a simple body plan, has recently been suggested to be sister group to the Acoelomorpha, together forming the new phylum Xenacoelomorpha. The phylogenetic position of the phylum is still under debate, either as an early branching bilaterian or as a sister ...
Put a tiger in your tank: the polyclad flatworm Maritigrella crozieri as a proposed model for evo-devo.
EvoDevo 4(1):29 (2013)
Polyclad flatworms are an early branching clade within the rhabditophoran Platyhelminthes. They provide an interesting system with which to explore the evolution of development within Platyhelminthes and amongst Spiralia (Lophotrochozoa). Unlike most other flatworms, polyclads undergo spiral cle...
Field et Al. Redux.
EvoDevo 4(1):5 (2013)
On 12 February 1988 (by coincidence Charles Darwin's birthday), a paper published in Science by Katherine Field, Rudy Raff, and colleagues presented the first credible molecular analysis of metazoan phylogeny based on sequences from the small subunit ribosomal RNA gene (SSU). Here I examine the ...
Comparative gene expression supports the origin of the incisor and molar process from a single endite in the mandible of the red flour beetle Tribolium castaneum.
EvoDevo 4(1):1 (2013)
The biting edge of the primitive arthropod mandible consists of a biting incisor process and a crushing molar process. These structures are thought to be derived from a structure known as an endite but the precise details of this are not understood. Various hypotheses concerning the number of e...
Cap'n'collar differentiates the mandible from the maxilla in the beetle Tribolium castaneum.
EvoDevo 3(1):25 (2012)
The biting mandible of the arthropods is thought to have evolved in the ancestor of the insects, crustaceans and myriapods: the Mandibulata. A unique origin suggests a common set of developmental genes will be required to pattern the mandible in different arthropods. To date we have functional ...
Invertebrate evolution: bringing order to the molluscan chaos.
Current Biology 21(23):R964 (2011)
While the seven classes within the phylum Mollusca are clearly defined morphologically and molecularly, relationships between them have long been contentious. Two recent phylogenomic studies take an important step forward with intriguing implications for their evolution.
Copyright © 2011 Elsevie...
MicroRNAs and phylogenomics resolve the relationships of Tardigrada and suggest that velvet worms are the sister group of Arthropoda.
PNAS 108(38):15920 (2011)
Morphological data traditionally group Tardigrada (water bears), Onychophora (velvet worms), and Arthropoda (e.g., spiders, insects, and their allies) into a monophyletic group of invertebrates with walking appendages known as the Panarthropoda. However, molecular data generally do not support t...