Silurian (Ludlow) acastid trilobites from Gotland and Scania, Sweden

Acastid trilobites from Ludlow strata on Gotland include three stratigraphically non-overlapping species of Acastella Reed: Acastella madidipes n. sp. (Hemse Marl and Eke Beds), A. breviceps (Angelin 1851) (Burgsvik Beds), and A. amatrix n. sp. (Hamra Beds, and probably Burgsvik Beds). Type and other material of A. breviceps (Angelin) from the Klinta Formation, Scania, is revised. Meraspid and early holaspid material of Acastella is described. Some characters support Acaste and allied taxa of mostly Wenlock age as a monophyletic subfamily Acastinae. Acastella as widely recognized is a grade with Devonian species more closely related to Asteropyginae than to the Ludlow type species. Baltic Ludlow-Př0idolí species previously placed in Scotiella Delo form a distinct group, Ewacaste n. gen., that includes a species from the uppermost Eke Beds on Gotland.