Morphobank

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.

Specimen: † Eoredlichia (unvouchered)
View: whole specimen (fossil)

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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.

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Article DOI: 10.1017/S0263593300000596

This project contains	Matrices
2 Media 1 Matrix 1 Document 37 Taxa 2 Specimens 54 Characters Total size of project's media files: 2.38M 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

Creation Date:
30 March 2024
Publication Date:
01 April 2024
Project views: 581

Authors' Institutions

Natural History Museum, London

University of Bristol

Members

Shreya Jariwala
Project Administrator

1797
(1588, 0, 209)

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. Last Modified in 03/30/24	1	45	44	0	9	0	0	1
[2] † Aglaspidida n. sp. Last Modified in 03/30/24	4	45	44	0	6	0	0	1
[3] † Alalcomenaeus Last Modified in 03/30/24	0	48	46	0	8	0	0	1
[4] † Buenaspis Last Modified in 03/30/24	22	30	29	0	3	0	0	1
[5] † Burgessia Last Modified in 03/30/24	1	45	45	0	8	0	0	1
[6] † Cindarella Last Modified in 03/30/24	0	51	51	0	3	0	0	1
[7] † Emeraldella Last Modified in 03/30/24	0	49	49	0	5	0	0	1
[8] † Eoredlichia Last Modified in 03/30/24	0	52	52	0	2	0	0	1
[9] † Fortiforceps Last Modified in 03/30/24	0	48	46	0	8	0	0	1
[10] † Helmetia Last Modified in 03/30/24	14	37	37	0	3	0	0	1
[11] † Jianfengia Last Modified in 03/30/24	0	48	46	0	8	0	0	1
[12] † Kuamaia Last Modified in 03/30/24	2	49	49	0	3	0	0	1
[13] † Leanchoilia Last Modified in 03/30/24	0	49	46	0	8	0	0	1
[14] † Liwia Last Modified in 03/30/24	26	26	26	0	2	0	0	1
[15] † Misszhouia Last Modified in 03/30/24	0	48	48	0	6	0	0	1
[16] † Naraoia Last Modified in 03/30/24	1	47	47	0	6	0	0	1
[17] † Olenoides Last Modified in 03/30/24	0	52	52	0	2	0	0	1
[18] † Paleomerus Last Modified in 03/30/24	27	23	23	0	4	0	0	1
[19] † Retifacies Last Modified in 03/30/24	0	50	50	0	4	0	0	1
[20] † Saperion Last Modified in 03/30/24	10	36	36	0	8	0	0	1
[21] † Sidneyia Last Modified in 03/30/24	2	47	47	0	5	0	0	1
[22] † Sinoburius Last Modified in 03/30/24	5	46	46	0	3	0	0	1
[23] † Skioldia Last Modified in 03/30/24	17	29	29	0	8	0	0	1
[24] † Tariccoia Last Modified in 03/30/24	20	32	31	0	3	0	0	1
[25] † Tegopelte Last Modified in 03/30/24	10	38	36	0	8	0	0	1
[26] † Xandarella Last Modified in 03/30/24	1	50	50	0	3	0	0	1
[27] † Yohoia Last Modified in 03/30/24	1	48	46	0	7	0	0	1
[28] † Cheloniellon Last Modified in 03/30/24	1	46	46	0	7	0	0	1
[29] † Eurypterida Last Modified in 03/30/24	0	48	48	0	6	0	0	1
[30] † Lemoneites Last Modified in 03/30/24	27	24	24	0	3	0	0	1
[31] Pycnogonida Last Modified in 03/30/24	2	43	43	0	9	0	0	1
[32] † Soomaspis Last Modified in 03/30/24	20	32	31	0	3	0	0	1
[33] † Weinbergina Last Modified in 03/30/24	0	48	48	0	6	0	0	1
[34] † Marrella Last Modified in 03/30/24	2	43	43	0	9	0	0	1
[35] † Mimetaster Last Modified in 03/30/24	2	45	44	0	8	0	0	1
[36] Crustacea Last Modified in 03/30/24	1	46	46	0	7	0	0	1
[37] Arthropoda n. sp. Last Modified in 03/30/24	1	45	45	0	8	0	0	1

Project views

type	number of views	Individual items viewed (where applicable)
Total project views	581
Project overview	36
Bibliography	20
Documents list	26
Matrix views	29	Matrix landing page (29 views);
Taxon list	257
Views for media list	36
Specimen list	66
Media views	111	Media search (82 views); M902812 (14 views); M902811 (15 views);