Universität zu Köln

Schoenemann, Brigitte and Clarkson, Euan N. K. (2017). Vision in fossilised eyes. Earth Environ. Sci. Trans. R. Soc. Edinb., 106 (4). S. 209 - 221. CAMBRIDGE: CAMBRIDGE UNIV PRESS. ISSN 1755-6929

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Abstract

This paper presents a review of recent developments in the study of vision in fossil arthropods, beginning with a discussion of the origin of visual systems. A report of the eyes of Cambrian arthropods from different Lagerstatten, especially the compound and median arthropod eyes from the Chengjiang fauna of China, is given. Reference is made also to compound eyes from the lower Cambrian Emu Bay Shale fauna of Australia and the Sirius Passet fauna of Greenland; also to the three-dimensionally preserved Orsten' fauna of Sweden. An understanding of how these eyes functioned is possible by reference to living arthropods and by using physical tools developed by physiologists. The eyes of trilobites (lower Cambrian to Upper Permian) are often very well preserved, and the structure and physiology of their calcite lenses, and the eye as a whole, are summarised here, based upon recent literature. Two main kinds of trilobite eyes have been long known. Firstly, there is the holochroal type, in which the lenses are usually numerous, small and closely packed together; this represents the ancestral kind, first found in lowermost Cambrian trilobites. The second type is the schizochroal eye, in which the lenses are relatively much larger and each is separated from its neighbours. Such eyes are confined to the single suborder Phacopina (Lower Ordovician to Upper Devonian). This visual system has no real equivalents in the animal kingdom. In this present paper, the origin of schizochroal eyes, by paedomorphosis from holochroal precursors, is reviewed, together with subsequent evolutionary transitions in the Early Ordovician. A summary of new work on the structure and mineralogy of phacopid lenses is presented, as is a discussion of the recent discovery of sublensar sensory structures in Devonian phacopids, which has opened up new dimensions in the study of trilobite vision.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schoenemann, Brigitte UNSPECIFIED UNSPECIFIED UNSPECIFIED Clarkson, Euan N. K. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-240379
DOI:	10.1017/S1755691016000232
Journal or Publication Title:	Earth Environ. Sci. Trans. R. Soc. Edinb.
Volume:	106
Number:	4
Page Range:	S. 209 - 221
Date:	2017
Publisher:	CAMBRIDGE UNIV PRESS
Place of Publication:	CAMBRIDGE
ISSN:	1755-6929
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language TRILOBITE EYES; COMPOUND EYES; PHACOPID TRILOBITES; SAOURA VALLEY; SOUTH CHINA; EVOLUTION; ONTOGENY; ARTHROPODS; SCHIZOCHROAL; BIODIVERSITY Multiple languages Geosciences, Multidisciplinary; Paleontology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/24037