The stage and its name were established by
Austrian geologists
Wilhelm Heinrich Waagen and
Carl Diener in 1895. The name comes from
Anisus, the
Latin name of the river
Enns. The original
type locality is at
Großreifling in the
Austrian state of
Styria. The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of
conodont species
Chiosella timorensis in the stratigraphic record. Other stratigraphers prefer to use the base of
magnetic chronozone MT1n. There is no accepted global reference profile for the base, but one (
GSSP or golden spike) was proposed at a flank of the mountain
Deșli Caira in the
Romanian
Dobruja. The top of the Anisian (the base of the Ladinian) is at the first appearance of
ammonite species
Eoprotrachyceras curionii and the ammonite
family Trachyceratidae. The conodont species
Neogondolella praehungarica appears at the same level. Especially in Central Europe the Anisian Stage is sometimes subdivided into four substages:
Aegean,
Bythinian,
Pelsonian and
Illyrian. The Anisian contains six ammonite
biozones: • zone of
Nevadites • zone of
Hungarites • zone of
Paraceratites • zone of
Balatonites balatonicus • zone of
Kocaelia • zone of
Acrochordiceras == Selected formations ==