Calcichordate hypothesis

<p>The calcichordate hypothesis, formulated by <a href="/facts/British_Museum/mq5LadWV">British Museum</a> <a href="/facts/Paleontologist/60n5yldd">paleontologist</a> <a href="/facts/Dick_Jefferies/B7lYa5S1">Richard Jefferies</a>, holds that each separate lineage of <a href="/facts/Chordate/AldL6ARm">chordate</a> (<a href="/facts/Cephalochordate/q1qQ98wI">Cephalochordates</a>, <a href="/facts/Urochordate/9e4penn8">Urochordates</a>, <a href="/facts/Craniate/Q2TECkHz">Craniates</a>) evolved from its own lineage of <a href="/facts/Mitrate/V8Lwfj25">mitrate</a>, and thus the <a href="/facts/Echinoderm/j2rd8qwt">echinoderms</a> and the chordates are <a href="/facts/Sister_group/pNNuVex4">sister groups</a>, with the <a href="/facts/Hemichordate/51nn9BUX">hemichordates</a> as an out-group.  It has been disproven by the discovery that the "tail" of <a href="/facts/Stylophoran/eyQPQesN">Stylophorans</a> contains a water vascular system, ambulacrum, and tube feet.  However, the clade <a href="/facts/Olfactores/yp73a26I">Olfactores</a> was first proposed as part of the calcichordate theory, and has since been validated through genetic <a href="/facts/Sequencing/ncpzobwG">sequencing</a>, albeit without the involvement of mitrates.
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Calcichordate hypothesis open-in-new

Calcichordate hypothesis