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An abnormal pygidium of the trilobite Brachymetopus ornatus Woodward from the Lower Carboniferous of Derbyshire
Author(s) -
Owen A. W.,
Tilsley J. W.
Publication year - 1996
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/(sici)1099-1034(199612)31:4<389::aid-gj718>3.0.co;2-x
Subject(s) - carboniferous , geology , paleontology , structural basin
A pygidium of Brachymetopus ornatus Woodward shows an abnormally developed left side affecting the whole of the pleural area and its rib development. Such an extensive abnormality, which does not extend beyond the axial furrow and shows none of the signs of resulting from injury, is currently unique. It is interpreted as a teratological condition in which a genetic or developmental malfunction resulted in the partial mimicking of thoracic pleurae rather than the construction of the normal pygidial pleural ribs. The effects of this are progressively greater from the posterior to the anterior parts of the affected pleural region. © 1996 John Wiley & Sons, Ltd.