Lower Devonian Rhynchonellid Brachiopods from the Ougarta Area (Western Sahara, Algeria)
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Lower Devonian rhynchonellid brachiopods from the Ougarta area (western Sahara, Algeria) D en ise Br ic e, Kh e ir a Bo u m e n d j e l, Pa t r ic k R. Ra c h e b o e u f& Be r n a r d M o t t e q u in The description and study of rhynchonellid brachiopods recently collected from the Lower Devonian of the Ougarta area in western Algerian Sahara permitted the revision of previously described and/or listed taxa, mainly from Morocco. Palaeobiogeographically, the nine identified taxa share many similarities with the rhynchonellid fauna of the Ibaimaghian Domain. Five of the nine identified taxa belong to three genera of the Family Nucinulidae Sartenaer, 2004. Three of these are new taxa, namely Nucinulus orbignyanus crassicosta subsp. nov., Cuninulus ougartaensis sp. nov. and Palinulus saharaensis sp. nov. The four remaining taxa are assigned (one of them questionably) to the genera Lanceomyonia, Stenorhynchia and G lossim dus of the families Hebetoechiidae, Trigonirhynchiidae, and Glossinotoechiidae, respectively. • Key words: Lower Devonian, Western Sahara, rhynchonellid brachiopods. BRICE, D., B o u m e n d je l , K„ RACHEBOEUF, P.R. & MOTTEQUIN, B. 2011. Lower Devonian rhynchonellid brachio pods from the Ougarta area (western Sahara, Algeria).Bulletin of Geosciences 86(1), 71-90 (14 figures, 10 tables). Czech Geological Survey, Prague. ISSN1214-1119. Manuscript received April 28, 2010; accepted in revised foim De cember 13, 2010; published online March 10, 2011; issued March 14, 2011. Denise Brice (corresponding author). Faculté Libre des Sciences et Technologies & Institut Supérieur d'Agriculture, Université catholique de Lille, 41 rue du Port 59046 Lille Cedex, France; [email protected] • Kheira Boumendjel, SONATRACH, Centre de Recherche et Développement, Av. du 1er Novembre, 35000 Boumerdès, Algeria • Patrick R. Racheboeuf, Université Européenne de Bretagne, Université de Bretagne Occidentale, CNRS, UMR 6538, Domaines Océaniques, UFR Sciences et Techniques, Paléontologie, 6 Av. Le Gorgeu - C.S. 93837, F-29238 Brest-cedex, France; [email protected] • Bernard Mottequin, Unité de paléontologie animale et humaine. Université de Liège, Bât. B18 Allée du 6 Août, B4000 Liège 1, Belgium; [email protected] The ‘Homogénéisation Programme' of the SONATRACH, complete revision of previously described taxa from West initiated in 2004, aimed at a detailed biostratigraphic and ern Sahara, including Morocco. This includes the revision biogeographic revision of the Cambrian-Devonian succes of specimens described by Le Maître ( 1944,1952) from the sion in the western Algerian Sahara. This program includ Tafilalt (Morocco) and from the Ougarta area (Algeria), ed two field trips in the Ahnet area (2004) and the Ougarta and more recently by Boumendjel et a l (1997a, b). area (2005), respectively. As a result, a first collective The Rhynchonellida described herein belong to the fam work concentrated on the Cambrian-Ordovician time in ilies Hebetoechiidae Havlicek, 1960, Trigonirhynchiidae terval, focusing in particular on the Late Ordovician glacia McLaren, 1965, Glossinotoechiidae Havlicek, 1992, and tion and its impact on the development of the Lower Palae Nucinulidae Sartenaer, 2004. Following Sartenaer (2004, ozoic transgression on northern Gondwana (Ghienne et al. 2005), who described western European taxa usually as 2007). A second collective study, dealing with the signed to the Family Uncinulidae Rzhonsnitskaia, 1956 Silurian-Early Devonian time interval is in progress. This and to the genus Uncinulus Bayle, 1878, a revision of the paper presents the first results highlighting taxonomical North African species fonnerly attributed to these taxo and biostratigraphical aspects. The purpose of this collec nomic units becomes necessary in order to establish their tive work is restricted to the Silurian-Early Devonian time possible assignation to the different units recently defined interval, and follows the publication by Wendt et a l (2006) (family, genus, species). dedicated to the Middle and Upper Devonian of the Ahnet and Mouydir (Algerian Sahara). The present paper is dedicated to the rhynchonellid Geological setting brachiopods collected in 2004 and 2005 by one of us (P.R.). The discovery of relatively abundant, well-pre From the two Algerian areas studied and sampled, the Ah served specimens, some of which new taxa, implied the net and Ougarta (Fig. 1A) areas, only the second yielded DOI 10.3140/bull, geosci.1198 71 Bulletin of Geosciences • Vol. 86, 1, 2011 ABBES Figure 1. A - simplified map of the Mediterranean Sea Ougarta mountains (modified from Ouali Mehadjiet al. 2004). • B - sim Oran % plified geological map of the Haci Z erham r Fegaguira area (modified from Ser A l g e r i a H am ad a M arhoum a vice de la Carte géologique de MOROCCO I R e c e n t l’Algérie 1952). • C - geological map □ □ Erg of the Ougarta area with location of the studied sections and those cited in _ Bem -Abbes H a m m a d a the text (modified from Boumendjel p • I Carboniferous etal. 1997a). 1 I Devonian Ougarta Mountains Djebel Silurian H eche □ Ordovician C am b rian R o ad 5 0 0 km T rack 10 km O ugart M a u r i t a n i a N Charouine Kseib Sections DK D k h issa ED Erg D jem el LK El K seib MH M arh o u m a Haci TSO Ougarta syncline closure Fegaguira ZH Z e rh am ra Lower Devonian rhynchonellid brachiopods. All rhyncho- lowing recent study and revision,Nue inulus orbignyanus nellids from the Ougarta area described in this paper have crassicostus sub sp. nov., Cuninulus ougartaensis sp. been collected from the Haci Fegaguira section (also called nov., Palinulus soharaensis sp. nov., andIPalinulus sp. Djebel Heche section, or Timimoun section in the eastern These are present in numerous sections (Figs 1C, 2): part of the area), about 35 km WSW of Timimoun town, Marhouma, Haci Fegaguira, Erg Djemel, El Kseib in up and from the Marhouma section (‘km 30’ section of the li per Emsian (Paris et al. 1997) except Palinulus terature). sohar aensis sp. nov. which is only known with certainty In the Haci Fegaguira section (Figs IB, 2), rhyn- in Tafilalt (Morocco), its presence in Ougarta being un chonellids were collected in the lowermost part of the certain. Dkhissa Formation. Lanceomyonia aff. occidentalis was collected in a coquina found 11m above the base of the for mation, and 5 m above the bed with strophochonetids. Material and methods ILanceomyonia borealiformis was found 5 m higher in the succession, associated with other brachiopods [Hollardina The rhynchonellids studied are part of Le Maître (1944, plana, Proschizophoria sp., Mclearnites (Mclearnites) cf. 1952) and Boumendjel et al. (1997a, b) collections and lecaroensis, etc.] and trilobites (Acastelia tanzidensis, some were collected by Racheboeuf in 2005. All sampled Digonas zemmourensis). Stenorhynchia briceae was col localities are situated in Algeria (Ougarta) and Morocco lected from the top of the ‘barre A ’, which is equivalent to (Tafilalt). Further information on the localities is provided the ‘Muraille de Chine’. Specimens collected in 2004 and by Le Maître (1944,1952), Boumendjel et al. (1997a), Pa 2005 from the Marhouma section (Figs 1C, 2) are from the ris et al. (1997) and above. lower part of the Chefar el Ahmar Formation, correspond Le Maître’s collections are deposited in the Faculté Li ing to the MH 19-28 sampling interval of Boumendjelet bre des Sciences & Technologies (Lille, France) and cata al. (1997a). The Nucinulidae Sartenaer, 2004 include fol logued with the prefix GFCL; Boumendjelet al. and 72 Denise Brice et al. * Lower Devonian rhynchonellid brachiopods from Algeria Marhouma section Erg Djemel section El Kseib section Haci Fegaguira (MA) (ED) (EK) section 39-43 34-36 80-82 32 35 30 • •• 28 • •®#0#®_ 20 CD® (D 19-20 co co .CO CD c o 3 2 55 2 cd c CD 3 § CD CO CO Ci ■£2 cl^ 3 3 2 w m -11 = O co co .co y . S'? Cn 3 2 o C .CO co co co CO C/3 SC CD CO CO 3 § 3 C O CO 32 S2 3 (goniatite 3 2 c ° § 1 CÜ co bed) CO CO to co 2 PM co D ^ §oO 2 c c •8* « I l o 0 CO 0^0 _2 -5 Muraille .c A de o Chine ® Ougarta 100 m Syncline closure (TSO) *=cd ct Dkhissa section 2c SvP (DK) o CD 25-26 Op .CD I sandstone chronostratigraphic AA>l limestone boundary I shale/siltstone lithostratigraphic • present boundary O dubious ® uncertain position * species cited by Ouali Mehadji (2003) and Ouali Mehadji et al. (2004) j F ig u re 2. Lithological correlations and age assignment of the Lower Devonian formations identified in the investigated sections of the Ougarta area and distribution of the rhynchonellid brachiopods (modified from Paris et al. 1997). Racheboeuf s collections are curated at the Laboratoire de MC - median costae, MPC - median parietal costae, PC - Paléontologie, UFR Sciences et Techniques, Université de parietal costae, T - thickness of the shell, W - width of the Bretagne Occidentale (Brest, France) and indicated by the shell, Ws - width of the sulcus. prefix LPB. Internal features have been studied by serial transverse sections with preparation of peels and drawings with the Systematic palaeontology camera lucida. Family Hebetoechiidae Havlicek, 1960 Abbreviations. - Localities: DK - Dkhissa, ED - Erg Dje Subfamily Hebetoechiinae Havlicek, 1960 mel, LK - El Kseib, MH - Marhouma, PO - ‘Piste d’Ougarta’, TSO - Ougarta syncline closure, ZH - Zer- Genus Lcinceomyonia Havlicek, 1960 hamra. Systematic palaeontology: A A - apical angle, DC - dorsal costae, L - length of the shell, LC - lateral costae, Type species. - Terebratula tarda Barrande, 1847. 73 Bulletin of Geosciences • Vol. 86, 1, 2011 Figure 3. A-J- Lanceomyonia occidentalis Drot, 1964.