Drepanura
premesnili
Many thousands of species of trilobites have been
described in the paleontological literature. Species were first named
& described starting in the late 1760s, but trilobites were discussed in
the literature long before this.
The oldest known reference to trilobite fossils in the
literature is a 4th century A.D. Chinese book by Guo Po (276-324 A.D.).
This book mentions trilobite-bearing fossiliferous limestones that have been
called “batstones” by the Chinese for many centuries.
Drepanura premesnili pygidium (2.9 cm across at its widest) - this
trilobite pygidium (tail) is in a fossiliferous wackestone from the Kushan
Formation (~uppermost Middle Cambrian) of Shandong Province, northeastern
China. Kushan limestones contain a relatively diverse trilobite
fauna. The most distinctive trilobite in Kushan rocks is Drepanura
premesnili Bergeron, 1899 (Arthropoda, Trilobita, Polymerida, Damesellidae).
The pygidia of Drepanura have strikingly large anterolateral
spines. When portions of the pygidia are covered in matrix, these Drepanura
tails resemble flying bats (see below) - hence “batstones”.
Batstone from the Kushan Formation (Cambrian) of
Shandong, China. Note the flying bat
shape of the pygidium at upper right (from Chang, 1921).
Drepanura premesnili pygidium in the logo of the Geological Survey of China
(from cover of Sun, 1935 - Palæontologia Sinica,
Series B 7(2)).
Drepanura premesnili tails dominate the surfaces of these Kushan Formation
batstones from Shandong, China.
(left: James St. John collection; right:
Nanjing Institute of Geology and Palaeontology collection)
Drepanura premesnili tails in fossiliferous limestone (above & below),
details of a large batstone slab from the Kushan Formation (Cambrian) of
Shandong, China.
FMNH 13897 (Field Museum of Natural History, Chicago,
Illinois, USA). Centimeter scale.
Reference cited:
Chang, H.T. 1921. Lapidarium sinicum, a
study of the rocks, minerals, fossils and metals as known in Chinese
literature. Memoir of the Geological Survey of China, Series B,
number 2. 348 pp. 11 pls. [in Chinese; English preface] [2nd
edition published 1927: 432 pp., 20 pls., 1 chart]