Morphology, palaeoecology and phylogenetic interpretation of the Cambrian echinoderm Vyscystis (Barrandian area, Czech Republic)
Abstract
The lepidocystoid echinoderm Vyscystis is known from the mid-Cambrian (Drumian) Jince Formation of the Příbram-Jince Basin (Czech Republic). Recently collected specimens of this genus, which are very well preserved, provide important new information, resulting in an improved understanding of their morphology (particularly the oral surface), growth trends and an assessment of their phylogenetic position and palaeoecology.
Vyscystis is characterized by an aboral imbricate cup and a flattened tessellate oral surface, bearing exotomous curved ambulacra supporting coiled brachioles. A phylogenetic analysis suggests a basal position of lepidocystoids among blastozoans.
Vyscystis shares plesiomorphic characters with other lepidocystoids (e.g. calyx) and some edrioasteroids (curvature of the ambulacra). It shows homoplasies (exotomous ambulacral pattern and coiled brachioles) with more derived eocrinoids (e.g.
Gogia). Vyscystis was probably a low-level suspension feeder, living attached to hard debris on a soft substrate.
Attachment to skeletal fragments was probably achieved by some sort of 'biogluing'.