New Late Devonian phacopid trilobites from Marhouma, SW Algerian Sahara
Authors:
Feist R, Mahboubi A, Girard C
Published in:
Bulletin of Geosciences, volume 91, issue 2;
pages: 243 - 259;
Received 20 December 2015;
Accepted in revised form 12 April 2016;
Online 26 May 2016
Keywords:
phacopid trilobites,
Late Devonian,
SW Algerian Sahara,
stratigraphy,
taxonomy,
environment,
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Abstract
Late Devonian phacopid trilobites of the SW Algerian Sahara are recognised as being the most diversified in cratonic North Gondwana. The first trilobites in the Frasnian of Algeria were discovered in the Marhouma S section near Beni Abbes: the new genus
Chlupacops with two species
Ch. laticeps gen. et sp. nov. and
Ch. aff.
cryphoides (Richter&Richter) are described from the uppermost part of the Cheffar el Ahmar Formation of mid-Frasnian age. The latter taxon is compared with the type material of
Ch. cryphoides (Richter&Richter) from Sessacker (Rhenish Slate Mts). New occurrences of lower Famennian phacopids in the “Argiles de Marhouma” Formation comprise the new genus
Enigmapyge with its type species
E. marhoumensis gen. et sp. nov., two species of
Trimerocephalus:
T. mahboubii sp. nov. and
T. caecus (Gürich), two species of
Trifoliops:
Tr. cronierae sp. nov. and
Tr. trifolius (Osmólska). In the middle Famennian, pygidia of
Dianops cf.
algeriensis Crônier were discovered. With the exception of the latter all taxa of the Marhouma S section can be assigned to conodont zones. The Algerian Late Devonian phacopids comprise predominantly blind or reduced-eyed taxa of basinal offshore environment. They are closely related to contemporaneous occurrences on the epicontinental margins of Laurussia as well as in Gondwana derived terranes and as such bear witness of the absence of oceanic barriers.