Project 2667: J. Bardin, I. Rougeta, F. Cecca. 2017. The phylogeny of Hildoceratidae (Cephalopoda, Ammonitida) resolved by an integrated coding scheme of the conch. Cladistics. 33:21-40.
Specimen: † Harpoceras subplanatum (unvouchered)
View: shell

Abstract

Ammonite phylogeny has mainly been established based on a stratigraphic approach, with cladistics underconsidered. The main arguments against the use of cladistics are the supposed large amount of homoplasy and the small number of characters. Resolving the phylogeny of the Hildoceratidae (Early Jurassic) is especially challenging because of its large diversity and disparity. Many forms that have not been determined as closely related in previous studies exhibit very similar shapes. Moreover, some groups are morphologically very different, adding difficulties to building a unique coding scheme at a low taxonomic resolution
(i.e. species). Here we propose an integrated coding scheme of the peristome shape and the ornamentation, allowing an increased level of comparison. The shape of the peristome is used as a new reference to locate ornamental features and propose new homology hypotheses. In total, 105 taxa have been analysed for 47 characters. We code continuous characters by their means and ranges +/- one standard deviation. We test two weighting schemes: equal weights standardized by unit range and implied weighting with several concavity constants. This work has led to redefinition of the phylogenetic inclusivenesses of all the hildoceratid subfamilies. The new coding scheme based on peristome shapes provides the fewest homoplastic characters. The schemes appear promising to improve phylogenetic analyses in ammonoids as well as molluscs as a whole by creating a general coding framework.


Read the article »

Article DOI: DOI: 10.1111/cla.12151

Project DOI: 10.7934/P2667, http://dx.doi.org/10.7934/P2667
This project contains
  • 1 Media
  • 2 Documents
  • 31 Taxa
  • 1 Specimen


Download Project SDD File
Currently Viewing:
MorphoBank Project 2667
  • Creation Date:
    21 April 2017
  • Publication Date:
    05 May 2017
  • Project views: 4493


    Members

    member name taxa specimens media
    MorphoBank Curator
    Project Administrator
    Last logged in 08/14/17
    3111
    Jérémie Bardin
    Full membership
    Last logged in Never
    000


    Project has no matrices defined.



    Project views

    type number of views Individual items viewed (where applicable)
    Total project views4493
    Project overview639
    Media views1177Media search (859 views); M451029 (318 views);
    Documents list295
    Views for media list309
    Specimen list443
    Taxon list1427
    Bibliography203




    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project64
    Project downloads60
    Document downloads4matrix (3 downloads); Characters (1 download);