Project 724: J. C. Lamsdell. 2013. Revised systematics of Palaeozoic ‘horseshoe crabs’ and the myth of monophyletic Xiphosura. Zoological Journal of the Linnean Society. 167:1–27.
Abstract
The monophyly of the class Xiphosura is critically re-examined. For the first time a phylogenetic analysis of a number of synziphosurine and xiphosurid taxa is performed together with representatives of the other chelicerate Orders also included as ingroup taxa. Xiphosura as currently defined is shown to be paraphyletic, and a revised classification is presented. Previous characteristics used to unite the xiphosurids (possessing a fused thoracetron) and a paraphyletic grade of synziphosurines (retaining freely articulating opisthosomal tergites) include the presence of a cardiac lobe, ophthalmic ridges, an axial region of the opisthosoma and a reduced first opisthosomal segment. All of these characteristics are however here shown to be present in other chelicerate groups, leaving Xiphosura without any defining synapomorphies. A number of other characters, including the form of the chelicerae and appendage VII, indicate that xiphosurans may be paraphyletic with respect to a clade consisting of chasmataspidids, eurypterids, and arachnids. What ramifications this has for the evolution of basal chelicerates is briefly discussed, and it is recognised that most of the currently known ‘synziphosurine’ taxa represent offshoots from the main chelicerate lineage with ghost ranges extending into at least the Middle Ordovician.Read the article »
Project DOI: 10.7934/P724, http://dx.doi.org/10.7934/P724
This project contains | Matrices |
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Download Project SDD File | Total scored cells: 3042 Total media associated with cells: 0 Total labels associated with cell media: 0 |
Characters | |
Total characters: 114 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 295 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:114/0 |
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MorphoBank Project 724
MorphoBank Project 724
- Creation Date:
25 April 2012 - Publication Date:
10 January 2013 - Project views: 38931
- Matrix downloads: 22
Authors' Institutions
- University of Kansas
Members
member name | taxa | specimens | media | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||
James Lamsdell Project Administrator | 37 | 1 | 1 | 114 | 0 | 0 | 3042 (2668, 0, 374) | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M1800' (37 Taxa)
taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] Fuxianhuia protensa Last Modified in 12/05/13 | 9 | 78 | 78 | 0 | 27 | 0 | 0 | 1 |
[2] Leanchoilia illecebrosa Last Modified in 12/05/13 | 17 | 87 | 87 | 0 | 10 | 0 | 0 | 1 |
[3] Alalcomenaeus cambricus Last Modified in 12/05/13 | 9 | 95 | 95 | 0 | 10 | 0 | 0 | 1 |
[4] Yohoia tenuis Last Modified in 12/05/13 | 27 | 76 | 76 | 0 | 11 | 0 | 0 | 1 |
[5] Emeraldella brocki Last Modified in 12/05/13 | 11 | 88 | 88 | 0 | 15 | 0 | 0 | 1 |
[6] Sydneyia inexpectans Last Modified in 12/05/13 | 15 | 86 | 86 | 0 | 13 | 0 | 0 | 1 |
[7] Olenoides serratus Last Modified in 12/05/13 | 2 | 100 | 100 | 0 | 12 | 0 | 0 | 1 |
[8] Pycnogonum litorale Last Modified in 12/05/13 | 3 | 59 | 59 | 0 | 52 | 0 | 0 | 1 |
[9] Haliestes dasos Last Modified in 12/05/13 | 13 | 52 | 52 | 0 | 49 | 0 | 0 | 1 |
[10] Palaeoisopus problematicus Last Modified in 12/05/13 | 7 | 61 | 61 | 0 | 46 | 0 | 0 | 1 |
[11] Offacolus kingi Last Modified in 12/05/13 | 38 | 71 | 71 | 0 | 5 | 0 | 0 | 1 |
[12] Weinbergina opitzi Last Modified in 12/05/13 | 29 | 84 | 84 | 0 | 1 | 0 | 0 | 1 |
[13] Camanchia grovensis Last Modified in 12/05/13 | 62 | 50 | 50 | 0 | 2 | 0 | 0 | 1 |
[14] Venustulus waukeshaensis Last Modified in 12/05/13 | 53 | 59 | 59 | 0 | 2 | 0 | 0 | 1 |
[15] Willwerathia laticeps Last Modified in 12/05/13 | 62 | 52 | 52 | 0 | 0 | 0 | 0 | 1 |
[16] Lunataspis aurora Last Modified in 12/05/13 | 64 | 47 | 47 | 0 | 3 | 0 | 0 | 1 |
[17] Limulus polyphemus Last Modified in 12/05/13 | 0 | 106 | 106 | 0 | 8 | 0 | 0 | 1 |
[18] Paleolimulus signatus Last Modified in 12/05/13 | 24 | 85 | 85 | 0 | 5 | 0 | 0 | 1 |
[19] Stoermeropterus conicus Last Modified in 12/05/13 | 10 | 100 | 100 | 0 | 4 | 0 | 0 | 1 |
[20] Eurypterus tetragonophthalmus Last Modified in 12/05/13 | 1 | 105 | 105 | 0 | 8 | 0 | 0 | 1 |
[21] Rhenopterus diensti Last Modified in 12/05/13 | 8 | 103 | 103 | 0 | 3 | 0 | 0 | 1 |
[22] Parastylonurus ornatus Last Modified in 12/05/13 | 14 | 97 | 97 | 0 | 3 | 0 | 0 | 1 |
[23] Chasmataspis laurencii Last Modified in 12/05/13 | 51 | 59 | 59 | 0 | 4 | 0 | 0 | 1 |
[24] Octoberaspis ushakovi Last Modified in 12/05/13 | 33 | 75 | 75 | 0 | 6 | 0 | 0 | 1 |
[25] Centruroides vittatus Last Modified in 12/05/13 | 1 | 98 | 98 | 0 | 15 | 0 | 0 | 1 |
[26] Palaeophonus nuncius Last Modified in 12/05/13 | 23 | 77 | 77 | 0 | 14 | 0 | 0 | 1 |
[27] Mastigoproctus giganteus Last Modified in 12/05/13 | 4 | 93 | 93 | 0 | 17 | 0 | 0 | 1 |
[28] Galeodes armeniacus Last Modified in 12/05/13 | 13 | 82 | 80 | 0 | 21 | 0 | 0 | 1 |
[29] Euproops anthrax Last Modified in 12/05/13 | 38 | 70 | 70 | 0 | 6 | 0 | 0 | 1 |
[30] Legrandella lombardi Last Modified in 12/05/13 | 57 | 57 | 57 | 0 | 0 | 0 | 0 | 1 |
[31] Bembicosoma pomphicus Last Modified in 12/05/13 | 71 | 43 | 43 | 0 | 0 | 0 | 0 | 1 |
[32] Bunodes lunula Last Modified in 12/05/13 | 69 | 43 | 43 | 0 | 2 | 0 | 0 | 1 |
[33] Limuloides limuloides Last Modified in 12/05/13 | 66 | 48 | 48 | 0 | 0 | 0 | 0 | 1 |
[34] Pasternakevia podolica Last Modified in 12/05/13 | 70 | 44 | 44 | 0 | 0 | 0 | 0 | 1 |
[35] Cyamocephalus loganensis Last Modified in 12/05/13 | 67 | 47 | 47 | 0 | 0 | 0 | 0 | 1 |
[36] Pseudoniscus roosevelti Last Modified in 12/05/13 | 70 | 44 | 44 | 0 | 0 | 0 | 0 | 1 |
[37] Kasibelinurus amoricum Last Modified in 12/05/13 | 67 | 47 | 47 | 0 | 0 | 0 | 0 | 1 |
Project views
type | number of views | Individual items viewed (where applicable) |
Total project views | 38931 | |
Project overview | 4252 | |
Media views | 6989 | Media search (6064 views); M108682 (925 views); |
Matrix views | 3247 | Matrix landing page (2882 views); Xiphosuran analysis (365 views); |
Specimen list | 3458 | |
Taxon list | 20974 | |
Documents list | 6 | |
Views for media list | 5 |
Project downloads
type | number of downloads | Individual items downloaded (where applicable) |
Total downloads from project | 403 | |
Matrix downloads | 22 | Xiphosuran analysis (22 downloads); |
Project downloads | 381 |