An Upper Ordovician (Katian) trilobite fauna from the Lower Ktaoua Formation, Morocco


Authors: Fortey RA, Edgecombe GD

Article in press: Received 13 March 2017; Accepted in revised form 18 July 2017; Online 11 August 2017

Keywords: Morocco, Ordovician, Katian, Declivolithus, Cyclopyge,

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A trilobite faunule from the Lower Ktaoua Formation at Jbel Tijarfaouine in the eastern part of the Anti-Atlas, Morocco, includes well-preserved articulated specimens of the trinucleid Declivolithus titan sp. nov., the cyclopygids Cyclopyge sibilla Šnajdr, 1982, and Heterocyclopyge sp., and the dalmanitid Eudolatites cf. E. galafrea Šnajdr, 1987. All species are either most closely related to or are conspecific with taxa from the middle Katian Bohdalec Formation in the Prague Basin, consistent with a supposed Katian age for the middle part of the Lower Ktaoua Formation and amplifying the close palaeogeographic affinities of Perunica and west Gondwana in the Late Ordovician. However, the Cyclopyge species is much more widespread, consistent with its supposed pelagic life habit, being found as far eastwards as Xinjiang Province, China.