Glyptocystida (Glyptocystids)
Order Glyptocystitida and especially its group Rhombifera are a small but successful group of derived blastozoan echinoderms that originated during the Late Cambrian (Ubaghs, 1999), were prominent in the fossil record by the end of the Early Ordovician, and had a peak in diversity during the Middle Ordovician (Sprinkle et al., 1996). On the whole the clade is extremely conservative, having a thecal plating formula that remained generally unchanged throughout its history, until its extinction by the early Late Devonian.
On/line reference: Broadhead a Sumrall (2003).
In the Virtual Museum there are total 14 samples | |||||||
![[ENG]](img/vlajka-cr.gif)
Česky 
Virtual museum of the Czech Geological Survey, www.geology.cz, (C) Czech Geological Survey, 2011, v.0.99 [13.12.2011]