Move from named fossils and three-dimensional anatomy to functional and genomic models without turning separate samples into an ancestor ladder.
Each step names its evidence claims, with references below. Interactive Explorer states are available in the full application; the narrative remains an editorial synthesis.
Parsimony and Bayesian analyses of sampled early artiopodans recover a short interval between inferred trilobite origin and the oldest widespread body fossils.
Tree shape, clock priors, character coding and survivorship bias condition the result; a modelled origin is not a fossil occurrence or a direct ancestor.
claim:event:early-trilobite-phylogenetic-clockX-ray microtomography resolves antennae, four post-antennal head-limb pairs, a labrum, a slit-like mouth and digestive tissues in articulated specimens.
The inferred feeding apparatus and homologies compare a rare local preservational window; they do not establish behaviour, ancestry or anatomy for every trilobite.
claim:event:tatelt-trilobite-3d-anatomyTriarthrus filaments have a narrow central region and inflated margins, while Olenoides preserves a partial body-wall attachment comparable to lamellate respiratory branches.
Gill function, haemolymph flow and limb-branch homology are functional interpretations from morphology across two taxa and times, not measured gas exchange.
claim:event:trilobite-upper-limb-gillSynchrotron microtomography maps ostracod valves, hyolith material and stylophoran plates through inventory specimen 8 at 11.35-micrometre voxel size.
Rapid indiscriminate feeding and a neutral-to-alkaline gut are inferences from one biased shelly meal; soft food and population variation are not preserved.
claim:event:bohemolichas-gut-contentsAdult Peronopsis and Ptychagnostus preserve biramous appendages and enrolment anatomy scored in an explicit arthropod character matrix.
The recovered sister relationship to polymeroid trilobites depends on sampled characters and taxa; crustacean-like limbs and life habit remain homoplastic or ecological interpretations.
claim:event:burgess-agnostid-topologyUrokodia preserves pincer-like short great appendages, overlapping exite flaps and a seven-segmented head in three dimensions.
Appendage homology and earliest-branching upper stem placement come from reconstruction and phylogenetic scoring and can change with competing character interpretations.
claim:event:urokodia-chelicera-book-gillKUMIP 314091a,b preserves massive chelicerae, five post-cheliceral prosomal limb pairs and lamella-bearing opisthosomal appendages.
Predatory ecology and a bridge between habeliids and synziphosurines are functional and topology results from one specimen and a scored matrix.
claim:event:megachelicerax-cheliceraeMCZ 1811 and USNM 305093 preserve optic nerves, a possible compact cephalic synganglion and a segmental ventral nerve cord.
Incomplete anterior preservation and conflict between nervous-system and appendage characters permit competing placements and mosaic-evolution scenarios.
claim:event:mollisonia-neuroanatomy-mosaicThe free ramus and associated cuticle directly establish a giant pterygotid chelicera from the Early Devonian Willwerath sample.
The approximately 2.5-metre body length assumes comparable chelicera-to-body proportions and limited positive allometry; it is not a complete skeleton measurement.
claim:event:jaekelopterus-giant-cheliceraThe analysis samples fossil and living xiphosurans and rescored euchelicerates across an expanded character matrix.
Polyphyly of traditional synziphosurines and internal Xiphosura relationships are topology results sensitive to coding, missing anatomy and taxon sampling.
claim:event:xiphosura-total-group-topologyHolotype UWGM 2162 and paratype UWGM 2163 preserve a scorpion body plan and medial structures compared with pulmonary-cardiovascular anatomy.
Book-lung homology and terrestrial physiology are interpretations; nearshore strata, transport and incomplete respiratory structures do not prove habitat.
claim:event:parioscorpio-terrestrializationDense living-taxon datasets and slowly evolving gene subsets recover either monophyletic Arachnida or Xiphosura nested among terrestrial lineages.
Gene choice, compositional heterogeneity, taxon sampling, morphology and model fit change the root; terrestrialization count and timing therefore remain topology-dependent. COL26.8 routes 104,126 strictly accepted species names through exact Chelicerata and Trilobita roots; that is nomenclatural coverage, not 104,126 mature dossiers or agreement among fossil, morphology and genomic models.
claim:event:arachnid-monophyly-conflict