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The visual system and paleoecology of the Silurian ostracod Primitiopsis planifrons

Gengo Tanaka, David J. Siveter and Andrew R. Parker
The visual system and paleoecology of the Silurian ostracod Primitiopsis planifrons
Journal of Paleontology (May 2009) 83 (3): 414-421

Abstract

Here we report the first detailed reconstruction of the eye and visual system of a Paleozoic ostracod, namely the dimorphic primitiopsid (Palaeocopa) Primitiopsis planifrons Jones, 1887. Evidence from the cuticular lens morphology and its position on the valve suggests that P. planifrons had a naupliar eye, which is the most common optical system in crustaceans. The characters of the eye, such as the separated cuticular lens on each valve and the strongly calcified nature of the lens and its diameter, are concordant with that of some Recent podocopid ostracods in which a divided type of naupliar eye is present. Ray tracing of the reconstructed cuticular lens of the primitiopsid species demonstrates strong spherical aberration and a very long focal length (as in the eye of podocopids), which implies the presence of a spherical mirror (tapetum) below the lens. Study of the ontogenetic change of the valve thickness aids the suggestion that P. planifrons was nektobenthic. The size of its cuticular lens in relation to that of living podocopid ostracods, and the water depth at which these Recent forms occur, indicates that P. planifrons may have lived in a relatively shallow, well lit environment such as the deep subtidal zone. These interpretations are consistent with supposed paleoenvironmental conditions derived from geological evidence. Thus, analysis of the nature and relative size of the eye gives an independent test to help identify paleoenvironmental parameters of long extinct ostracods.


ISSN: 0022-3360
EISSN: 1937-2337
Coden: JPALAZ
Serial Title: Journal of Paleontology
Serial Volume: 83
Serial Issue: 3
Title: The visual system and paleoecology of the Silurian ostracod Primitiopsis planifrons
Affiliation: Gunma Museum of Natural History, Tomioka, Japan
Pages: 414-421
Published: 200905
Text Language: English
Publisher: Paleontological Society, Lawrence, KS, United States
References: 45
Accession Number: 2009-060760
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 plate, 1 table, sketch map
N57°30'00" - N57°30'00", E18°30'00" - E18°30'00"
Secondary Affiliation: University of Leicester, GBR, United KingdomNatural History Museum, GBR, United Kingdom
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: 200933
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