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Early Ordovician trilobites from the Nazareno area, northwestern Argentina

M. Franco Tortello and Susana B. Esteban
Early Ordovician trilobites from the Nazareno area, northwestern Argentina
Journal of Paleontology (September 2014) 88 (5): 925-947


The upper part of the Santa Rosita Formation (Ordovician, Tremadocian) in the Nazareno area, Cordillera Oriental, northwestern Argentina, records the vertical passage of high-energy, shallow water platform environments to offshore settings. Eighteen trilobite species are described from this locality for the first time. Although the taxa from the lower part of the succession (Leptoplastides sp., Asaphellus sp.) are scarce and non-age diagnostic, those from the upper part include diverse assemblages partially assigned to the late Tremadocian Notopeltis orthometopa Zone. Systematic descriptions of several species (Geragnostus nesossii Harrington and Leanza, G. callaveiformis Harrington and Leanza, Asaphellus jujuanus Harrington, Notopeltis orthometopa [Harrington], Mekynophrys nanna Harrington, Ceratopyge forficuloides Harrington and Leanza, Apatokephalus tibicen Pribyl and Vanek) are improved, the genus Nileus Dalman (including N. australis n. sp.) is first reported from the Tremadocian of western Gondwana, and new species of Asaphellus Callaway (A. nazarenensis n. sp.), Conophrys Callaway, and Apatokephalus Brogger are described. The trilobites have their closest affinities with faunas from Norway and Sweden. Notopeltis orthometopa and Mekynophrys nanna are restricted to the uppermost part of the succession, well above the first records of most other trilobites recognized.

ISSN: 0022-3360
EISSN: 1937-2337
Serial Title: Journal of Paleontology
Serial Volume: 88
Serial Issue: 5
Title: Early Ordovician trilobites from the Nazareno area, northwestern Argentina
Affiliation: Museo de Ciencias Naturales de La Plata, Division Paleontologia Invertebrados, La Plata, Argentina
Pages: 925-947
Published: 201409
Text Language: English
Publisher: Paleontological Society, Lawrence, KS, United States
References: 120
Accession Number: 2014-082879
Categories: StratigraphyInvertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. col., geol. sketch map
S22°30'00" - S22°30'00", W65°07'00" - W65°07'00"
Secondary Affiliation: Universidad Nacional de Tucuman, ARG, Argentina
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, The Paleontological Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201443
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