ABSTRACT
Echinosphaerites is one of the most widely distributed of all “cystoids”. This rhombiferan is found in the Middle Ordovician of North America, northwestern Europe, Bohemia, Yunan, China and extends well into the Upper Ordovician strata of Bohemia. Echinosphaerites typically has a large globular polyplated theca, four to six basals, humatirhombs across all facets of thecal plates, two to five brachioles (some branch to produce up to seven or eight), and a very thin, rarely preserved column. Thecal plates have large cores and well developed growth rings which probably indicate Bohemia’s cooler waters and higher Ordovician paleolatitude than that of North America and/or Western Europe. The best documented Middle Ordovician locality in Bohemia is in the grewacke-like Zahorany Formation, Zahorany locality, Southwest of Prague.
