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Normalograptus kufraensis, a new species of graptolite from the western margin of the Kufra Basin, Libya

Published online by Cambridge University Press:  11 February 2013

ALEX PAGE ,
GUIDO MEINHOLD ,
DANIEL P. LE HERON  and
MOHAMED ELGADRY
ALEX PAGE*
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
GUIDO MEINHOLD
Affiliation:
CASP, University of Cambridge, West Building, 181A Huntingdon Road, Cambridge CB3 0DH, UK Department of Sedimentology & Environmental Geology, Geoscience Centre, University of Göttingen, Goldschmidtstraβe 3, 37077 Göttingen, Germany
DANIEL P. LE HERON
Affiliation:
Department of Earth Sciences, Queen's Building, Royal Holloway University of London, Egham, TW200EX, UK
MOHAMED ELGADRY
Affiliation:
Libyan Petroleum Institute, Gergarish Road, P. O. BOX 6431, Tripoli, Libya
*
†Author for correspondence: alexpageesq@gmail.com
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Abstract

Normalograptus kufraensis sp. nov. occurs as monospecific assemblages in the Tanezzuft Formation at the western margin of the Kufra Basin (Jabal Eghei), southern Libya. These graptolites have parallel-sided rhabdosomes with long, straight virgellae, climacograptid thecae and a full straight median septum. N. kufraensis is intermediate between Ordovician graptolites from the N. angustus (Perner) lineage and the younger sister species N. ajjeri (Legrand) and N. arrikini Legrand. N. kufraensis differs from these taxa as follows: it is broader than N. angustus; it has greater thecal spacing than N. ajjeri or N. arrikini. A table comparing measurements of N. kufraensis with 44 other Normalograptus taxa differentiates it from other members of this morphologically conservative group. Even though N. angustus and N. ajjeri are very long-ranging graptolites, a stratophenetic approach suggests that the specimens from Jabal Eghei may be of late Hirnantian or younger age. The faunal composition and preservation suggests these graptolites occupied the ‘cratonic invader’ biotope. The stratigraphic succession records deglacial flooding and fluctuating of redox in the Tanezzuft Formation, with the graptolites indicating a short-lived interval of anoxia.

Keywords

biostratigraphySilurianGondwanaAfricaevolutionglaciationPalaeozoic
Type
Original Articles
Information
Geological Magazine , Volume 150 , Issue 4 , July 2013 , pp. 743 - 755
Copyright
Copyright © Cambridge University Press 2013 

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Footnotes

‡

Current address: Dauntsey's School, West Lavington, Wiltshire SN10 4EP, UK

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