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GEOREF RECORD

Trilobite systematics; the last 75 years

Richard A. Fortey
Trilobite systematics; the last 75 years (in Special 75th anniversary issue, Jonathan M. Adrain (prefacer))
Journal of Paleontology (November 2001) 75 (6): 1141-1151

Abstract

The progress achieved in trilobite systematics over the last 75 years is briefly reviewed. Different approaches to phylogenetics have influenced the way trilobites have been classified. Classical evolutionary taxonomy, the stratigraphical approach, and cladistics have all contributed in different ways to the current classification, which has evolved piecemeal, and is still unsatisfactory is some ways. Nonetheless, progress towards a phylogenetic classification has been made, especially as the result of information from ontogenies provided by well-preserved silificified material. Trilobites are a well-defined clade within a larger arachnomorph group. Agnostida have been excluded from Trilobita, but are perhaps best considered as specialised trilobites, at least until limbs of eodiscids are described. The outstanding problems in classification of each trilobite order are reviewed. Most are concerned with the recognition of the appropriate Cambrian sister taxa, and the discovery of the relevant ontogenies. It is very likely that post-Cambrian clades "root" deeply into the Cambrian. The coherence, or otherwise, of Proetida, Asaphida, Corynexochida and the lichid/odontopleurid groups will be resolved by such studies. The problems of paraphyly in Ptychopariida and Redlichiina may prove more obdurate. The temporal brevity of certain Cambrian family ranges may be partly a taxonomic artefact. The possibility of a late Cambrian gap in the record on some clades should be considered.


ISSN: 0022-3360
EISSN: 1937-2337
Coden: JPALAZ
Serial Title: Journal of Paleontology
Serial Volume: 75
Serial Issue: 6
Title: Trilobite systematics; the last 75 years
Title: Special 75th anniversary issue
Author(s): Fortey, Richard A.
Author(s): Adrain, Jonathan M.prefacer
Affiliation: Natural History Museum, Department of Palaeontology, London, United Kingdom
Affiliation: University of Iowa, Department of Geoscience, Iowa City, IA, United States
Pages: 1141-1151
Published: 200111
Text Language: English
Publisher: Paleontological Society, Lawrence, KS, United States
References: 114
Accession Number: 2002-017960
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200207
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