Project 2131: P. Cong, X. Ma, X. Hou, G.D. Edgecombe, N.J. Strausfeld. 2014. Brain structure resolves the segmental affinity of anomalocaridid appendages. Nature. 513 (7519):538-542.
Specimen: † Lyrarapax unguispinus (YKLP/YKLP 13304:YKLP 13304)
View: part

Abstract

Despite being among the most celebrated taxa from Cambrian biotas, anomalocaridids (order Radiodonta) have provoked intense debate about their affinities within the moulting-animal clade that includes Arthropoda. Current alternatives identify anomalocaridids as either stem-group euarthropods1, 2, 3, crown-group euarthropods near the ancestry of chelicerates4, or a segmented ecdysozoan lineage with convergent similarity to arthropods in appendage construction5. Determining unambiguous affinities has been impeded by uncertainties about the segmental affiliation of anomalocaridid frontal appendages. These structures are variably homologized with jointed appendages of the second (deutocerebral) head segment, including antennae and ‘great appendages’ of Cambrian arthropods, or with the paired antenniform frontal appendages of living Onychophora and some Cambrian lobopodians. Here we describe Lyrarapax unguispinus, a new anomalocaridid from the early Cambrian Chengjiang biota, southwest China, nearly complete specimens of which preserve traces of muscles, digestive tract and brain. The traces of brain provide the first direct evidence for the segmental composition of the anomalocaridid head and its appendicular organization. Carbon-rich areas in the head resolve paired pre-protocerebral ganglia at the origin of paired frontal appendages. The ganglia connect to areas indicative of a bilateral pre-oral brain that receives projections from the eyestalk neuropils and compound retina. The dorsal, segmented brain of L. unguispinus reinforces an alliance between anomalocaridids and arthropods rather than cycloneuralians. Correspondences in brain organization between anomalocaridids and Onychophora resolve pre-protocerebral ganglia, associated with pre-ocular frontal appendages, as characters of the last common ancestor of euarthropods and onychophorans. A position of Radiodonta on the euarthropod stem-lineage implies the transformation of frontal appendages to another structure in crown-group euarthropods, with gene expression and neuroanatomy providing strong evidence that the paired, pre-oral labrum is the remnant of paired frontal appendages1.


Read the article »

Article DOI: 10.1038/nature13486

Project DOI: 10.7934/P2131, http://dx.doi.org/10.7934/P2131
This project containsMatrices
  • 2 Media
  • 1 Matrix
  • 32 Taxa
  • 1 Specimen
  • 55 Characters
Total size of project's media files: 6 MB

Download Project SDD File
Total scored cells: 1136
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 55
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 120
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:55/0
Currently Viewing:
MorphoBank Project 2131


    Members

    member name taxa specimens media chars character
    media
    labels
    cell scorings
    (scored, NPA, "-")
    cell
    medialabels
    rules
    Jo Wolfe
    Project Administrator
    Last logged in 03/16/15
    321255001136
    (998, 0, 138)
    000
    Greg Edgecombe
    Full membership
    Last logged in 03/16/15
    0000000
    (0, 0, 0)
    000
    Xiaoya Ma
    Full membership
    Last logged in Never
    0000000
    (0, 0, 0)
    000


    Taxonomic Overview for Matrix 'M23255' (32 Taxa)

    taxon unscored
    cells
    scored
    cells
    no cell
    support
    NPA
    cells
    "-" cellscell images labels on
    cell images
    member
    access
    [1] Caenorhabditis
    Last Modified in 03/13/15
    91414032003
    [2] Priapulus
    Last Modified in 03/13/15
    91414032003
    [3] † Aysheaia
    Last Modified in 03/13/15
    20323203003
    [4] † Kerygmachela
    Last Modified in 03/13/15
    14393902003
    [5] † Pambdelurion
    Last Modified in 03/13/15
    17363602003
    [6] † Opabinia
    Last Modified in 03/13/15
    18353502003
    [7] † Caryosyntrips
    Last Modified in 03/13/15
    30232302003
    [8] † Anomalocaris kunmingensis
    Last Modified in 03/13/15
    31242400003
    [9] † Amplectobelua stephenensis
    Last Modified in 03/13/15
    30252500003
    [10] † Amplectopbelua symbrachiata
    Last Modified in 03/13/15
    9454501003
    [11] † Lyrarapax unguispinus
    Last Modified in 03/13/15
    17373701003
    [12] † Anomalocaris canadensis
    Last Modified in 03/13/15
    0545401003
    [13] † NIGP 154565
    Last Modified in 03/13/15
    28272700003
    [14] † Anomalocaris saron
    Last Modified in 03/13/15
    5494901003
    [15] † Anomalocaris cf saron nevada
    Last Modified in 03/13/15
    27282800003
    [16] † Anomalocaris balang
    Last Modified in 03/13/15
    32232300003
    [17] † Paranomalocaris multisegmentalis
    Last Modified in 03/13/15
    28272700003
    [18] † Anomalocaris cf canadensis emu bay
    Last Modified in 03/13/15
    29262600003
    [19] † Anomalocaris pennsylvanica
    Last Modified in 03/13/15
    27222206003
    [20] † Tamisiocaris borealis
    Last Modified in 03/13/15
    27282800003
    [21] † Anomalocaris briggsi
    Last Modified in 03/13/15
    28272700003
    [22] † Fezouata hurdiid
    Last Modified in 03/13/15
    33232200003
    [23] † Peytoia nathorsti
    Last Modified in 03/13/15
    2535201003
    [24] † Schinderhannes
    Last Modified in 03/13/15
    15414000003
    [25] † Cf peytoia balang
    Last Modified in 03/13/15
    33222200003
    [26] † Hurdia victoria
    Last Modified in 03/13/15
    6494801003
    [27] † Hurdia cf victoria utah
    Last Modified in 03/13/15
    22333201003
    [28] † Stanleycaris hirpex
    Last Modified in 03/13/15
    26292900003
    [29] † Hurdia sp b burgess rom
    Last Modified in 03/13/15
    28262601003
    [30] † Hurdia sp b utah
    Last Modified in 03/13/15
    27282701003
    [31] † Chengjiangocaris
    Last Modified in 03/13/15
    13030024003
    [32] † Olenoides
    Last Modified in 03/13/15
    22929024003


    Project views

    type number of views Individual items viewed (where applicable)
    Total project views17554
    Project overview2551
    Media views4098Media search (3281 views); M374424 (423 views); M374425 (394 views);
    Taxon list5894
    Matrix views1820Matrix landing page (1648 views); Anomalocaridid brain matrix (172 views);
    Specimen list1431
    Views for media list1760




    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project179
    Matrix downloads3Anomalocaridid brain matrix (3 downloads);
    Project downloads176