Order Phacopida:

Suborder Cheirurina


This suborder was first identified by Hawle and Corda in 1847. The cephalon contains proparian sutures with the glabella usually expanding forwards or barrel shaped. There can be up to four pairs of furrows on the glabella. Genal spines may be present. The eyes are small or absent; if present they are holochroal. A rostral plate is present; hypostoma free. The thorax contains variable numbers of segments between 8 and 19, usually spine tipped. The thoracic segments/pleurae can be ridged, smooth or furrowed. The pygidium is usually highly modified with 2-4 pairs of pleural ribs and spines. The surface of Family Cheiruridae is commonly tuberculate, pitted or both. Diagram below shos main features of this suborder as do the photographed specimens.

 

 

Suborder Cheirurina 

Family Cheiruridae

Subfamily Cheirurinae

Genera Ceraurinella

Species typa

 Ceraurunella typa showing main features of this suborder (Pitted surface not included)

 

   

 Cheirurina sphaerexochus showing forward expanding pygidium and smooth thoracic segments

 Cheirurina encrinurus showing tuberculate surface on its cephalon



Author: Sarah Vinnell
Last updated: 21/11/05
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Websites produced by students on the MSc Palaeobiology programme in the Department of Earth Sciences at the University of Bristol for academic year 2005-6