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Trilobites of the genus Dikelokephalina from Ordovician Gondwana and Avalonia
Author(s) -
Fortey Richard A.
Publication year - 2010
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/gj.1275
Subject(s) - gondwana , baltica , trilobite , ordovician , genus , sterna , paleontology , biology , zoology , synonym (taxonomy) , evolutionary biology , geology , tectonics
The trilobite Dikelokephalina is widespread across the Tremadocian Gondwana, Avalonia and Baltica palaeocontinents. The hitherto poorly known Anglo‐Welsh species D. furca (Salter, 1866) is revised on the basis of new and well‐preserved material. A new species, D. brenchleyi sp. nov., is described from the Anti‐Atlas, Morocco. The two species together provide a fuller understanding of the genus, and of the family, Dikelokephalinidae (Kobayashi, 1934), to which it has been assigned. Suggestions that this family may be a junior synonym of Hungaiidae (Raymond, 1924) are considered premature. D. brenchleyi sp. nov. apparently shows variation in mature segment number, a most unusual feature in post‐Cambrian trilobites. It is found in monospecific assemblages of large individuals which lack ventral median sutures, and a case is made that these individuals represent a mass gathering of individuals that have ceased to grow, for the purpose of fertilizing eggs, as happens in living Limulus . Copyright © 2010 John Wiley & Sons, Ltd.