ArticleNature2015
Hallucigenia's head and the pharyngeal armature of early ecdysozoans.
Article in Nature, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 24 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
24 citing papers in PubMed, 82 citations in OpenAlex.
- Polychaete annelids from the earliest Cambrian Period.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- A fossilized ventral ganglion reveals a chaetognath affinity for Cambrian nectocaridids.Science advances · 2025Article
- Exotic cuticular specializations in a Cambrian scalidophoran.Proceedings. Biological sciences · 2025Article
- Preservation and early evolution of scalidophoran ventral nerve cord.Science advances · 2025Article
- Organ systems of a Cambrian euarthropod larva.Nature · 2024Article
- Molting in early Cambrian armored lobopodians.Communications biology · 2024Article
- Cambrian lobopodians shed light on the origin of the tardigrade body plan.Proceedings of the National Academy of Sciences of the United States of America · 2023Article
- The Cambrian cirratuliformProceedings. Biological sciences · 2023Article
- Muscle systems and motility of early animals highlighted by cnidarians from the basal Cambrian.eLife · 2022Article
- Ancestral morphology of Ecdysozoa constrained by an early Cambrian stem group ecdysozoan.BMC evolutionary biology · 2020Article
- Finding a home for hyoliths.National science review · 2020Article
- A new hurdiid radiodont from the Burgess Shale evinces the exploitation of Cambrian infaunal food sources.Proceedings. Biological sciences · 2019Article
- A Cambrian unarmoured lobopodian, †Lenisambulatrix humboldti gen. et sp. nov., compared with new material of †Diania cactiformis.Scientific reports · 2018Article
- A three-dimensionally preserved lobopodian from the Herefordshire (Silurian) Lagerstätte, UK.Royal Society open science · 2018Article
- Article
- Brain and eyes of Kerygmachela reveal protocerebral ancestry of the panarthropod head.Nature communications · 2018Article
- The functional head of the Cambrian radiodontan (stem-group Euarthropoda) Amplectobelua symbrachiata.BMC evolutionary biology · 2017Article
- Cambrian suspension-feeding lobopodians and the early radiation of panarthropods.BMC evolutionary biology · 2017Article
- Carboniferous Onychophora from Montceau-les-Mines, France, and onychophoran terrestrialization.Invertebrate biology : a quarterly journal of the American Microscopical Society and the Division of Invertebrate Zoology/ASZ · 2016Article
- Onychophoran-like musculature in a phosphatized Cambrian lobopodian.Biology letters · 2016Article
Corrections and comments
- Commented on by
Authors and funding
2 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The molecularly defined clade Ecdysozoa comprises the panarthropods (Euarthropoda, Onychophora and Tardigrada) and the cycloneuralian worms (Nematoda, Nematomorpha, Priapulida, Loricifera and Kinorhyncha). These disparate phyla are united by their means of moulting, but otherwise share few morphological characters--none of which has a meaningful fossilization potential. As such, the early evolutionary history of the group as a whole is largely uncharted. Here we redescribe the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the mid-Cambrian Burgess Shale. We document an elongate head with a pair of simple eyes, a terminal buccal chamber containing a radial array of sclerotized elements, and a differentiated foregut that is lined with acicular teeth. The radial elements and pharyngeal teeth resemble the sclerotized circumoral elements and pharyngeal teeth expressed in tardigrades, stem-group euarthropods and cycloneuralian worms. Phylogenetic results indicate that equivalent structures characterized the ancestral panarthropod and, seemingly, the ancestral ecdysozoan, demonstrating the deep homology of panarthropod and cycloneuralian mouthparts, and providing an anatomical synapomorphy for the ecdysozoan supergroup.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.