Project 542: J. C. Lamsdell. 2011. The eurypterid Stoermeropterus conicus from the lower Silurian Pentland Hills, Scotland. Monograph of the Palaeontographical Society. 165 (636):1-84 pls 1-15.
Specimen: † Stoermeropterus conicus (unvouchered)

Abstract

Stoermeropterus conicus (Eurypterida: Eurypterina), from the Telychian (Upper Llandovery, Silurian) of Pentland Hills near Edinburgh, Scotland, is described from material originally assigned to three different species (Nanahughmilleria conica, Drepanopterus bembycoides and Drepanopterus lobatus). Two other existing eurypterid species, Hughmilleria lata from the Wenlock of Norway and Drepanopterus nodosus from the Pridoli of North America are recognized as being congeneric with S. conicus, united principally by their possession of moveable mesosomal spines on the mesosoma, genital spatulae and a bulbous telson ‘boss’. Several characters support the assignment Stoermeropterus to Moselopteridae, the most basal eurypterine clade, including its possession of a pediform appendage VI with a modified ‘podomere’ 7a and the possession of a coxal ‘ear’, which may represent the remains of a much-reduced exopod. Stoermeropterus conicus resolves phylogenetically as the most basal known eurypterine, and can aid in reconstructing the eurypterid ground plan. As such an attempt is made to reconstruct the characteristics that are plesiomorphic for Eurypterida through comparison with basal Eurypterina, Stylonurina, chasmataspidids and synziphosurines. Several characteristics previously thought to be autapomorphies of Stylonurina, such as a three-segmented genital operculum, are now shown to actually be plesiomorphic conditions in respect to Eurypterida as a whole, while other apparently derived characteristics such as an epistoma and genital spatulae may be characters that are present in all eurypterids during the juvenile and are respectively either paedomorphically retained into adulthood or become hypertrophied in various species. Following the identification of a metastoma and genital appendage in some chasmataspidid species, the sole currently known eurypterid autapomorphy is identified as the fusion of the opercular plates of somites VIII and IX. Evolutionary relationships among the traditional ‘merostome’ groups are reviewed, primarily in light of segment articulations and the development of the appendage of somite VII. The concept that synziphosurines may represent a paraphyletic stem grade to a group inclusive of xiphosurids, chasmataspidids, eurypterids, and arachnids is proposed.


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Project DOI: 10.7934/P542, http://dx.doi.org/10.7934/P542
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 1 Document
  • 24 Taxa
  • 1 Specimen
  • 43 Characters
Total size of project's media files: 22 MB

Download Project SDD File
Total scored cells: 894
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 43
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 98
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:43/0
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MorphoBank Project 542


    Members

    member name taxa specimens media chars character
    media
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    (scored, NPA, "-")
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    James Lamsdell
    Project Administrator
    Last logged in 01/17/12
    24114300894
    (859, 0, 35)
    000
    MorphoBank Curator
    Full membership
    Last logged in 02/20/12
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    Taxonomic Overview for Matrix 'M1225' (24 Taxa)

    taxon unscored
    cells
    scored
    cells
    no cell
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    NPA
    cells
    "-" cellscell images labels on
    cell images
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    [1] † Weinbergina opitzi
    Last Modified in 12/05/13
    0353508002
    [2] † Brachyopterus stubblefieldi
    Last Modified in 12/05/13
    7333303002
    [3] † Parastylonurus ornatus
    Last Modified in 12/05/13
    0404003002
    [4] † Stoermeropterus conicus
    Last Modified in 12/05/13
    0434300002
    [5] † Stoermeropterus latus
    Last Modified in 12/05/13
    8353500002
    [6] † Stoermeropterus nodosus
    Last Modified in 12/05/13
    20232300002
    [7] † Vinetopterus struvei
    Last Modified in 12/05/13
    4393900002
    [8] † Vinetopterus martini
    Last Modified in 12/05/13
    10333300002
    [9] † Moselopterus ancylotelson
    Last Modified in 12/05/13
    1424200002
    [10] † Moselopterus elongatus
    Last Modified in 12/05/13
    4393900002
    [11] † Onychopterella augusti
    Last Modified in 12/05/13
    8343401002
    [12] † Onychopterella kokomoensis
    Last Modified in 12/05/13
    3393901002
    [13] † Dolichopterus macrocheirus
    Last Modified in 12/05/13
    0434300002
    [14] † Eurypterus remipes
    Last Modified in 12/05/13
    0424201002
    [15] † Hughmilleria socialis
    Last Modified in 12/05/13
    0424201002
    [16] † Tylopterella boylei
    Last Modified in 12/05/13
    26171700002
    [17] † Megalograptus ohioensis
    Last Modified in 12/05/13
    0414102002
    [18] † Mixopterus kiaeri
    Last Modified in 12/05/13
    1414101002
    [19] † Strobilopterus princetonii
    Last Modified in 12/05/13
    8353500002
    [20] † Erieopterus microphthalmus
    Last Modified in 12/05/13
    0424201002
    [21] † Rhenopterus diensti
    Last Modified in 12/05/13
    0393904002
    [22] † Octoberaspis ushakovi
    Last Modified in 12/05/13
    9303004002
    [23] † Loganamaraspis dunlopi
    Last Modified in 12/05/13
    18232302002
    [24] † Diploaspis casteri
    Last Modified in 12/05/13
    11292903002


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    Total project views21021
    Project overview3320
    Taxon list8190
    Specimen list1913
    Matrix views1675Matrix landing page (1472 views); Stoermeropterus and related basal Eurypterina (203 views);
    Media views3958Media search (3428 views); M88680 (530 views);
    Bibliography738
    Documents list1227




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    Total downloads from project179
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    Document downloads1Copyright information for exemplar media (1 download);
    Project downloads168
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