UPPER HOMERIAN (UPPER WENLOCK, SILURIAN) GRAPTOLITES FROM ARCTIC CANADA

An extraordinarily well-preserved upper Homerian (uppermost Wenlock) post-extinction (post-lundgreni Event) graptolite fauna is described from Arctic Canada. The fauna of dendroids, retiolitids and monograptids, predominantly of uncompressed and isolated material, demonstrates almost totally new mor...

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Bibliographic Details
Published in:Journal of paleontology 2002-03, Vol.76 (2), p.321-346
Main Authors: LENZ, A. C, KOZŁOWSKA-DAWIDZIUK, A
Format: Article
Language:English
Subjects:
Animals
Arctic Archipelago
Baculograptus
Bathurst Island
Biostratigraphy
biozones
Canada
correlation
Doliograptus
Earth sciences
Ellesmere Island
Fauna
faunal studies
Fossils
Geology
Homerian
Homerian age
invertebrate
Lower Silurian
morphology
New species
new taxa
Nunavut
Paleontology
Paleozoic
Papiliograptus
Queen Elizabeth Islands
range
Reticulum
Silurian
Sleeves
Species extinction
Spinograptus
taxonomy
type specimens
Umbrellas
Wenlock
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Description
Summary:An extraordinarily well-preserved upper Homerian (uppermost Wenlock) post-extinction (post-lundgreni Event) graptolite fauna is described from Arctic Canada. The fauna of dendroids, retiolitids and monograptids, predominantly of uncompressed and isolated material, demonstrates almost totally new morphological features in comparison with the pre-extinction fauna. The two species of the lowest post-extinction fauna are followed by a rapid proliferation in the middle part of the interval, resulting in the maximum diversity, 21 species, for the entire upper Homerian. The upper Homerian is divided into three biostratigraphic units: the lower nassa-dubius Biozone, middle praedeubeli-deubeli Biozone, and the upper ludensis Biozone. The total fauna consists of ten species of monograptids and 11 species of retiolitids; of the latter group, three (Baculograptus, Papiliograptus and Doliograptus) are new genera, and six (B. batesi, P. papilio, P.? petilus, D. latus, Doliograptus sp. A, and Spinograptus praerobustus) are new species. Among the recognized species of monograptids, only Colonograptus schedidoneus and Lobograptus? cornuatus are confined to the Arctic, while five species of retiolitids (B. batesi, P.? petilus, D. latus, Doliograptus sp. A, and Spinograptus praerobustus) appear to be endemic.
ISSN:0022-3360
1937-2337
DOI:10.1666/0022-3360(2002)076<0321:UHUWSG>2.0.CO;2