Acaste is a genus of extinct
trilobite of the order
Phacopida which lived throughout the
Silurian period (
Wenlock Group).[1] Though many species had been included, it now has only one species, Acaste downingiae.[2] It is characterized by a convex dorsal surface, an absence of spines, a shortening of the head-shield and a general rounding off of all angles.[3]
Etymology
A. lokii is named after
Loki, the Norse god of mischief. Loki tricked the blind god
Höðr to kill the god of beauty
Baldr, and so started the demise of the world (or
Ragnarök). This
epithet was chosen by Edgecombe because it is based on the cephalon of A. longisulcata, which has turned out to be a mixed collection. The pygidium of A. longisulcata belongs to a
Phacopoidea.[1]
A. zerinae is named in honor of Zerina Edgecombe, the wife of the species author.[1]
Taxonomy
Species previously assigned to Acaste
Some species originally designated to Acaste have now been reassigned to other genera.[4]
A. birminghamensis=Llandovacaste birminghamensis[1]
^H H Swinnerton - Outlines of Palaeontology, Edward Arnold (Publishers) Ltd, 1972 (p. 247)
ISBN0-7131-2357-5.
^Moore, R.C. (1959). Arthropoda I - Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha.
Treatise on Invertebrate Paleontology. Vol. Part O. Boulder, Colorado/Lawrence, Kansas: Geological Society of America/University of Kansas Press. pp. 1–560.
ISBN0-8137-3015-5.