Morphobank

Project 4796: T. J. Cotton, R. A. Fortey. 2005. Comparative morphology and relationships of the Agnostida. Crustacea and Arthropod Relationships. 16:95-136.

Specimen: † Acidiscus birdi (unvouchered)
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Abstract

The relationships of the agnostid trilobites have been controversial. They have been claimed as highly derived, neotenously-derived trilobites on the one hand, or as arthropods close to the stem group of crustaceans on the other. On the former view, their distinctive autapomorphies are regarded as specialisations related to their mode of life; on the latter, emphasis is placed on the differences from polymerid trilobites as indicating a separated erivation. We consider it necessary to include Eodiscina in any assessment of agnostid relationships. Previously suggested synapomorphies uniting crustaceans and agnostids to the exclusion of trilobites are reviewed, and the majority is rejected. A number of new synapomorphies uniting agnostids with all, or some eodiscinids are described. These characters are tested in the context of a cladistic analysis of 79 eodiscinid and 3 agnostid taxa. We conclude that agnostids are deeply nested within the eodiscinids. The eodiscinid family Weymouthiidae is strongly supported as sister taxon to the Agnostina. Several supposed agnostid autapomorphies are found to be synapomorphies shared with one or more eodiscinid group. At least as far as exoskeletal characters are concerned, the supposed distinctiveness of agnostids has been over-emphasised. To assert non-trilobite relationships of agnostids would require implausible levels of homoplasy.

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Article DOI: 10.1201/9781420037548.ch5

Project DOI: 10.7934/P4796, http://dx.doi.org/10.7934/P4796

This project contains	Matrices
6 Media 1 Matrix 1 Document 85 Taxa 6 Specimens 123 Characters Total size of project's media files: 38.84M Download Project SDD File	Total scored cells: 9985 Total media associated with cells: 0 Total labels associated with cell media: 0
	Characters
	Total characters: 123 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 299 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:123/0

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MorphoBank Project 4796

Creation Date:
31 July 2023
Publication Date:
01 August 2023
Project views: 3599
Media downloads: 1

Authors' Institutions

Natural History Museum, London

Members

Shreya Jariwala
Project Administrator

123

9985
(8194, 0, 1791)

Taxonomic Overview for Matrix 'M29403' (85 Taxa)

taxon	unscored cells	scored cells	no cell support	NPA cells	"-" cells	cell images	labels on cell images	member access
[1] † Abakolia minutus Last Modified in 07/31/23	2	101	98	0	23	0	0	1
[2] † Abakolia pauca Last Modified in 07/31/23	10	97	90	0	23	0	0	1
[3] † Acidiscus birdi Last Modified in 07/31/23	8	96	94	0	21	0	0	1
[4] † Acidiscus theristes Last Modified in 07/31/23	3	105	101	0	19	0	0	1
[5] † Acimetopus bilobatus Last Modified in 07/31/23	8	92	91	0	24	0	0	1
[6] † Alaskadiscus spinosus Last Modified in 07/31/23	2	107	104	0	17	0	0	1
[7] † Analox bipunctata Last Modified in 07/31/23	12	86	83	0	28	0	0	1
[8] † Bathydiscus dolichometopus Last Modified in 07/31/23	9	89	86	0	28	0	0	1
[9] † Bolboparia superba Last Modified in 07/31/23	12	94	93	0	18	0	0	1
[10] † Calodiscus lobatus Last Modified in 07/31/23	8	103	95	0	20	0	0	1
[11] † Cephalopyge notabilis Last Modified in 07/31/23	9	87	84	0	30	0	0	1
[12] † Chelediscus acifer Last Modified in 07/31/23	0	99	97	0	26	0	0	1
[13] † Chelediscus chathamensis Last Modified in 07/31/23	14	87	84	0	25	0	0	1
[14] † Cobboldites comleyensis Last Modified in 07/31/23	9	86	84	0	30	0	0	1
[15] † Cobboldites itsariensis Last Modified in 07/31/23	10	88	82	0	31	0	0	1
[16] † Dawsonia bohemicus Last Modified in 07/31/23	6	94	92	0	25	0	0	1
[17] † Dawsonia dawsoni Last Modified in 07/31/23	2	97	95	0	26	0	0	1
[18] † Delgadella caudatus Last Modified in 07/31/23	9	95	91	0	23	0	0	1
[19] † Delgadella lenaicus Last Modified in 07/31/23	2	98	97	0	24	0	0	1
[20] † Delgadella amouslekensis Last Modified in 07/31/23	16	86	84	0	23	0	0	1
[21] † Dicerodiscus tsunyiensis Last Modified in 07/31/23	19	86	84	0	20	0	0	1
[22] † Egyngolia willochra Last Modified in 07/31/23	9	104	100	0	14	0	0	1
[23] † Egyngolia obtusa Last Modified in 07/31/23	4	109	102	0	17	0	0	1
[24] † Egyngolia zaicevi Last Modified in 07/31/23	45	59	57	0	21	0	0	1
[25] † Ekwipagetia marginata Last Modified in 07/31/23	9	106	100	0	14	0	0	1
[26] † Ekwipagetia plicofimbria Last Modified in 07/31/23	8	105	100	0	15	0	0	1
[27] † Eodiscus borealis Last Modified in 07/31/23	3	100	96	0	24	0	0	1
[28] † Eodiscus scanicus Last Modified in 07/31/23	2	108	98	0	23	0	0	1
[29] † Hebediscina sardoa Last Modified in 07/31/23	8	104	99	0	16	0	0	1
[30] † Hebediscina blagonravovi Last Modified in 07/31/23	16	97	90	0	16	0	0	1
[31] † Hebediscina yuqingensis Last Modified in 07/31/23	12	104	99	0	12	0	0	1
[32] † Hebediscus attleborensis Last Modified in 07/31/23	16	86	84	0	23	0	0	1
[33] † Helepagetia bitruncula Last Modified in 07/31/23	8	107	101	0	14	0	0	1
[34] † Jinghediscus nummularius Last Modified in 07/31/23	11	93	89	0	23	0	0	1
[35] † Kiskinella cristata Last Modified in 07/31/23	11	99	98	0	14	0	0	1
[36] † Korobovia ocellata Last Modified in 07/31/23	8	97	94	0	21	0	0	1
[37] † Lenadiscus unicus Last Modified in 07/31/23	15	96	91	0	16	0	0	1
[38] † Leptochilodiscus punctulatus Last Modified in 07/31/23	8	89	85	0	30	0	0	1
[39] † Leptochilodiscus succinctus Last Modified in 07/31/23	1	100	95	0	27	0	0	1
[40] † Litometopus longispinus Last Modified in 07/31/23	9	87	86	0	28	0	0	1
[41] † Luvsanodiscus gammatus Last Modified in 07/31/23	0	104	101	0	22	0	0	1
[42] † Macannaia maladensis Last Modified in 07/31/23	1	115	110	0	12	0	0	1
[43] † Mallagnostus desideratus Last Modified in 07/31/23	47	53	52	0	24	0	0	1
[44] † Mallagnostus limbatus Last Modified in 07/31/23	8	87	84	0	31	0	0	1
[45] † Mallagnostus llarenai Last Modified in 07/31/23	6	96	91	0	26	0	0	1
[46] † Meniscuchus menetus Last Modified in 07/31/23	8	92	88	0	27	0	0	1
[47] † Meniscuchus nanus Last Modified in 07/31/23	12	85	84	0	27	0	0	1
[48] † Natalina incita Last Modified in 07/31/23	15	96	90	0	18	0	0	1
[49] † Natalina dilata Last Modified in 07/31/23	20	89	86	0	17	0	0	1
[50] † Neocobboldia dentata Last Modified in 07/31/23	3	99	97	0	23	0	0	1
[51] † Neopagetina rjonsnitzkii Last Modified in 07/31/23	9	104	101	0	13	0	0	1
[52] † Ninadiscus strobulatus Last Modified in 07/31/23	12	94	89	0	22	0	0	1
[53] † Oodiscus subgranulatus Last Modified in 07/31/23	10	88	87	0	26	0	0	1
[54] † Opsidiscus bilobatus Last Modified in 07/31/23	12	102	95	0	16	0	0	1
[55] † Opsidiscus microspinus Last Modified in 07/31/23	1	112	107	0	15	0	0	1
[56] † Opsidiscus longispinus Last Modified in 07/31/23	40	71	69	0	14	0	0	1
[57] † Pagetia bootes Last Modified in 07/31/23	1	111	109	0	13	0	0	1
[58] † Pagetia prolata Last Modified in 07/31/23	1	113	110	0	12	0	0	1
[59] † Pagetides elegans Last Modified in 07/31/23	1	115	109	0	13	0	0	1
[60] † Pagetides fragum Last Modified in 07/31/23	8	106	101	0	14	0	0	1
[61] † Pseudocobboldia pulchra Last Modified in 07/31/23	10	97	93	0	20	0	0	1
[62] † Runcinodiscus index Last Modified in 07/31/23	8	93	91	0	24	0	0	1
[63] † Semadiscus sollennis Last Modified in 07/31/23	40	59	58	0	25	0	0	1
[64] † Serrodiscus speciosus Last Modified in 07/31/23	1	103	98	0	24	0	0	1
[65] † Serrodiscus gravestocki Last Modified in 07/31/23	11	95	91	0	21	0	0	1
[66] † Serrodiscus daedalus Last Modified in 07/31/23	10	95	91	0	22	0	0	1
[67] † Serrodiscus ctenoa Last Modified in 07/31/23	0	101	98	0	25	0	0	1
[68] † Sinodiscus shipaiensis Last Modified in 07/31/23	0	103	101	0	22	0	0	1
[69] † Sinodiscus subquadratus Last Modified in 07/31/23	8	98	94	0	21	0	0	1
[70] † Sinopagetia jinnanensis Last Modified in 07/31/23	10	97	96	0	17	0	0	1
[71] † Stigmadiscus stenometopus Last Modified in 07/31/23	15	86	84	0	24	0	0	1
[72] † Tannudiscus altus Last Modified in 07/31/23	10	89	83	0	30	0	0	1
[73] † Tannudiscus balanus Last Modified in 07/31/23	0	97	94	0	29	0	0	1
[74] † Tchernyshevioides ninae Last Modified in 07/31/23	8	99	96	0	19	0	0	1
[75] † Tsunyidiscus niutitangensis Last Modified in 07/31/23	1	112	109	0	13	0	0	1
[76] † Tsunyidiscus kaiyangensis Last Modified in 07/31/23	5	112	106	0	12	0	0	1
[77] † Tsunyidiscus aclis Last Modified in 07/31/23	9	107	103	0	11	0	0	1
[78] † Tsunyidiscus orientalis Last Modified in 07/31/23	1	108	104	0	18	0	0	1
[79] † Tsunyidiscus longquanensis Last Modified in 07/31/23	0	107	104	0	19	0	0	1
[80] † Weymouthia nobilis Last Modified in 07/31/23	27	74	72	0	24	0	0	1
[81] † Yukonia intermedia Last Modified in 07/31/23	1	112	105	0	17	0	0	1
[82] † Yukonides lacrinus Last Modified in 07/31/23	9	105	98	0	16	0	0	1
[83] † Condylopyge amitina Last Modified in 07/31/23	2	96	94	0	27	0	0	1
[84] † Peronopsis roddyi Last Modified in 07/31/23	2	95	92	0	29	0	0	1
[85] † Ptychagnostus gibbus Last Modified in 07/31/23	1	99	97	0	25	0	0	1

Project views

type	number of views	Individual items viewed (where applicable)
Total project views	3599
Project overview	262
Documents list	121
Matrix views	125	Matrix landing page (119 views); Cotton and Fortey 2005 (6 views);
Media views	878	Media search (403 views); M890501 (76 views); M890502 (69 views); M890503 (66 views); M890504 (72 views); M890505 (121 views); M890506 (71 views);
Views for media list	149
Taxon list	1320
Specimen list	651
Bibliography	93

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type	number of downloads	Individual items downloaded (where applicable)
Total downloads from project	1
Media downloads	1	M890505 (1 download);