Emmrichops

Emmrichops is a genus of average size trilobite (about 6 centimetres or 2.4 inches), assigned to the Cyclopygidae family, that lived during the Middle Ordovician (Llanvirn), and have been found in what are today the Czech Republic and in Wales. Like other cyclopygids, it has huge eyes, that occupy almost the entire free cheeks (or librigenae)), six thorax segments and a wide tail shield. Like the other cyclopygids, Emmrichops probably lived hunting plankton in the water column. Only one species, E. planicephala, has been described sofar.

Etymology

Emmrichops was named in honor of the German geologist Hermann Emmrich (1815–1879). The species epithet planicephala is derived from the Latin planum, meaning "flat" and cephalon, "head".

Distribution

• Emmrichops planicephala is known from the Ordovician of Wales (Hustedograptus teretiusculus biozone, Llanfawr Mudstones Formation, Builth inlier, Llandeilian Stage of the Llanvirn Series) and the Czech Republic (Dobrotiva Formation, near Svatá Dobrotivá, Vokovice and Veleslavín, all Prague Basin).^[1]

Description

The head shield (or cephalon) is twice as wide as long, widest at ⅔ of its length from the front, it lacks genal spines, the posterior margin is outwards curving slightly forward across the axis and slightly backwards across the pleurae. The thorax is slightly tapering to the back, 1¾× as wide as long. The thorax axis is strongly tapering, from almost half at the front to almost ⅓ as wide as the thorax at the back. The frontal thorax segment may carry a node at its rear edge. The third thorax segment may show two pits, like Pricyclopyge. The tail shield (or pygidium) is wide triangular (3× as wide as long), with somewhat concave sides, and a wide border. The pygidial axis (or rhachis) is clearly defined, but segmentation is not discernible.

References