Project 5177: T. J. Cotton, S. J. Braddy. 2003. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences. 94 (3):169-193.
Abstract
A new hypothesis of the relationships between arachnomorph arthropods, and the origin of chelicerates, is presented based on a cladistic analysis of 34 taxa and 54 characters. The present study provides a detailed discussion of primary hypotheses of homology and includes a more complete range of terminal taxa than previous analyses. The analysis provides the first convincing synapomorphies for the Arachnomorpha, and suggests that the marrellomorphs are not arachnomorphs. The assignment of Cambrian 'great appendage' (or megacheiran) arthropods to the Arachnomorpha is confirmed, and potential synapomorphies uniting them with chelicerates are discussed and tested. Principal amongst these are the loss of the first cephalic appendages (the antennae), loss of the exopods of the second cephalic appendages and modification of the endopods of these appendages into spinose grasping organs. The Arachnomorpha consists of two major clades: (1) a 'chelicerate-allied' clade, including chelicerates, megacheirans, Emeraldella, Sidneyia, cheloniellids and aglaspidids, in which chelicerates and a paraphyletic group of megacherian arthropods form the sister group to the remaining taxa; and; (2) a 'trilobite-allied' clade, including trilobites, xandarellids, helmetiids, tegopeltids and naraoiids, the relationships of which are more fully resolved than in previous studies.Read the article »
Article DOI: 10.1017/S0263593300000596
| This project contains | Matrices |
|---|---|
Download Project SDD File  | Total scored cells: 1797 Total media associated with cells: 0 Total labels associated with cell media: 0 |
| Characters | |
| Total characters: 54 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 124 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:54/0 |
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MorphoBank Project 5177
MorphoBank Project 5177
- Creation Date:
30 March 2024 - Publication Date:
01 April 2024
Authors' Institutions
- Natural History Museum, London
- University of Bristol
Members
| member name | taxa |
specimens |
media | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||
| Shreya Jariwala Project Administrator | 37 | 2 | 2 | 54 | 0 | 0 | 1797 (1588, 0, 209) | 0 | 0 | 0 | ||||
Taxonomic Overview for Matrix 'M29768' (37 Taxa)
| taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
| [1] † Aglaspidida n.sp. Taxon name last Modified on 03/30/24 | 1 | 45 | 44 | 0 | 9 | 0 | 0 | 1 |
| [2] † Aglaspidida n. sp. Taxon name last Modified on 03/30/24 | 4 | 45 | 44 | 0 | 6 | 0 | 0 | 1 |
| [3] † Alalcomenaeus Taxon name last Modified on 03/30/24 | 0 | 48 | 46 | 0 | 8 | 0 | 0 | 1 |
| [4] † Buenaspis Taxon name last Modified on 03/30/24 | 22 | 30 | 29 | 0 | 3 | 0 | 0 | 1 |
| [5] † Burgessia Taxon name last Modified on 03/30/24 | 1 | 45 | 45 | 0 | 8 | 0 | 0 | 1 |
| [6] † Cindarella Taxon name last Modified on 03/30/24 | 0 | 51 | 51 | 0 | 3 | 0 | 0 | 1 |
| [7] † Emeraldella Taxon name last Modified on 03/30/24 | 0 | 49 | 49 | 0 | 5 | 0 | 0 | 1 |
| [8] † Eoredlichia Taxon name last Modified on 03/30/24 | 0 | 52 | 52 | 0 | 2 | 0 | 0 | 1 |
| [9] † Fortiforceps Taxon name last Modified on 03/30/24 | 0 | 48 | 46 | 0 | 8 | 0 | 0 | 1 |
| [10] † Helmetia Taxon name last Modified on 03/30/24 | 14 | 37 | 37 | 0 | 3 | 0 | 0 | 1 |
| [11] † Jianfengia Taxon name last Modified on 03/30/24 | 0 | 48 | 46 | 0 | 8 | 0 | 0 | 1 |
| [12] † Kuamaia Taxon name last Modified on 03/30/24 | 2 | 49 | 49 | 0 | 3 | 0 | 0 | 1 |
| [13] † Leanchoilia Taxon name last Modified on 03/30/24 | 0 | 49 | 46 | 0 | 8 | 0 | 0 | 1 |
| [14] † Liwia Taxon name last Modified on 03/30/24 | 26 | 26 | 26 | 0 | 2 | 0 | 0 | 1 |
| [15] † Misszhouia Taxon name last Modified on 03/30/24 | 0 | 48 | 48 | 0 | 6 | 0 | 0 | 1 |
| [16] † Naraoia Taxon name last Modified on 03/30/24 | 1 | 47 | 47 | 0 | 6 | 0 | 0 | 1 |
| [17] † Olenoides Taxon name last Modified on 03/30/24 | 0 | 52 | 52 | 0 | 2 | 0 | 0 | 1 |
| [18] † Paleomerus Taxon name last Modified on 03/30/24 | 27 | 23 | 23 | 0 | 4 | 0 | 0 | 1 |
| [19] † Retifacies Taxon name last Modified on 03/30/24 | 0 | 50 | 50 | 0 | 4 | 0 | 0 | 1 |
| [20] † Saperion Taxon name last Modified on 03/30/24 | 10 | 36 | 36 | 0 | 8 | 0 | 0 | 1 |
| [21] † Sidneyia Taxon name last Modified on 03/30/24 | 2 | 47 | 47 | 0 | 5 | 0 | 0 | 1 |
| [22] † Sinoburius Taxon name last Modified on 03/30/24 | 5 | 46 | 46 | 0 | 3 | 0 | 0 | 1 |
| [23] † Skioldia Taxon name last Modified on 03/30/24 | 17 | 29 | 29 | 0 | 8 | 0 | 0 | 1 |
| [24] † Tariccoia Taxon name last Modified on 03/30/24 | 20 | 32 | 31 | 0 | 3 | 0 | 0 | 1 |
| [25] † Tegopelte Taxon name last Modified on 03/30/24 | 10 | 38 | 36 | 0 | 8 | 0 | 0 | 1 |
| [26] † Xandarella Taxon name last Modified on 03/30/24 | 1 | 50 | 50 | 0 | 3 | 0 | 0 | 1 |
| [27] † Yohoia Taxon name last Modified on 03/30/24 | 1 | 48 | 46 | 0 | 7 | 0 | 0 | 1 |
| [28] † Cheloniellon Taxon name last Modified on 03/30/24 | 1 | 46 | 46 | 0 | 7 | 0 | 0 | 1 |
| [29] † Eurypterida Taxon name last Modified on 03/30/24 | 0 | 48 | 48 | 0 | 6 | 0 | 0 | 1 |
| [30] † Lemoneites Taxon name last Modified on 03/30/24 | 27 | 24 | 24 | 0 | 3 | 0 | 0 | 1 |
| [31] Pycnogonida Taxon name last Modified on 03/30/24 | 2 | 43 | 43 | 0 | 9 | 0 | 0 | 1 |
| [32] † Soomaspis Taxon name last Modified on 03/30/24 | 20 | 32 | 31 | 0 | 3 | 0 | 0 | 1 |
| [33] † Weinbergina Taxon name last Modified on 03/30/24 | 0 | 48 | 48 | 0 | 6 | 0 | 0 | 1 |
| [34] † Marrella Taxon name last Modified on 03/30/24 | 2 | 43 | 43 | 0 | 9 | 0 | 0 | 1 |
| [35] † Mimetaster Taxon name last Modified on 03/30/24 | 2 | 45 | 44 | 0 | 8 | 0 | 0 | 1 |
| [36] Crustacea Taxon name last Modified on 03/30/24 | 1 | 46 | 46 | 0 | 7 | 0 | 0 | 1 |
| [37] Arthropoda n. sp. Taxon name last Modified on 03/30/24 | 1 | 45 | 45 | 0 | 8 | 0 | 0 | 1 |