Open AccessAgnostid trilobites from the Upper Ordovician of Sweden and Bomholm, Denmark
Author(s) -
Per Ahlberg
Publication year - 1989
Publication title -
bulletin of the geological society of denmark
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.674
H-Index - 28
eISSN - 2245-7070
pISSN - 0011-6297
DOI - 10.37570/bgsd-1988-37-17
Subject(s) - ordovician , fauna , paleontology , mediterranean climate , geology , geography , kazakh , archaeology , ecology , biology , linguistics , philosophy
Arthrorhachis tarda (Barrande, 1846) and Sphaeragnostus cingulatus (Olin, 1906) are described from the Upper Ordovician (Harjuan Series) of Sweden and Bornholm, Denmark. S. cingulatus is extremely rare, while A. tarda is generally abundant in middle Ashgillian strata and known from a great number of localities in southern and south-central Scandinavia. Outside Scandinavia, A. tarda is frequently encoun- tered in the pre-Himantian Ashgill of Poland, Bohemia, various parts of the British Isles, and Kazakhstan. In most of these areas, the species is generally confined to mudstone sequences, and it is usually associated with faunas of Mediterranean type. The generic concept of Sphaeragnostus is revised.