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Giant trilobites and trilobite clusters from the Ordovician of Portugal

Juan C. Gutierrez-Marco, Artur A. Sa, Diego C. Garcia-Bellido, Isabel Rabano and Manuel Valerio
Giant trilobites and trilobite clusters from the Ordovician of Portugal
Geology (Boulder) (May 2009) 37 (5): 443-446


Large quarrying surfaces of roofing slate in the Arouca Geopark (northern Portugal), formed under oxygen-depleted conditions, have yielded a unique Ordovician fossil lagerstatte that reveals new information on the social behavior of trilobites. It provides several of the world's largest trilobite specimens (some reaching 70 cm), showing evidence of possible polar gigantism in six different species, as well as numerous examples of monotaxic and polytaxic size-segregated autochthonous trilobite clusters, some of which contain as many as 1000 specimens. These reveal a very diverse social behavior, which includes temporary refuge from predation and synchronous molting and reproduction, demonstrated for the first time in five contemporary families of three different trilobite orders from a single formation.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 37
Serial Issue: 5
Title: Giant trilobites and trilobite clusters from the Ordovician of Portugal
Affiliation: Facultad de Ciencias Geologicas, Departamento de Paleontologia, Madrid, Spain
Pages: 443-446
Published: 200905
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 22
Accession Number: 2009-050009
Categories: Invertebrate paleontologyStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2009109
Illustration Description: illus. incl. geol. sketch map
N40°30'00" - N41°30'00", W08°00'00" - W08°00'00"
Secondary Affiliation: Universidade de Tras-os-Montes e Alto Douro, PRT, PortugalMuseo Geominero-IGME, ESP, SpainCentro de Interpretacao Geoligica de Canelas, PRT, Portugal
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200927
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