Famennian rhynchonellides (Brachiopoda) from deep-water facies of the Ougarta Basin (Saoura Valley, Algeria)

Abstract

In the Saoura Valley (Ougarta Basin, Saharan Algeria), the lower–upper Famennian part of the essentially shally Marhouma Formation is characterized by deep-water facies and includes horizons rich in ammonoids (goniatites and clymeniids) and blind to eye-reduced phacopide trilobites. They are also rich in small-sized and smooth rhynchonellide brachiopods, investigated here for the first time in order to detail their post-Kellwasser recovery. Rhynchonellides clearly predominate in the brachiopod assemblages (representing 90% of the whole assemblage, with 10 species) composed otherwise of athyridides, orthides and spiriferides. Rhynchonellides are mostly represented by relatively flat leiorhynchids and rozmanariids consistent with poor oxygenation on the sea floor. One new species is described (Evanidisinurostrum saouraense sp. nov.); four genera, previously known only from the south-eastern margin of Laurussia, are reported for the first time from the northern margin of Gondwana: the leiorhynchid Sphaeridiorhynchus and the rozmanariids Leptoterorhynchus, Pugnaria and Novaplatirostrum.

Brachiopod faunas from the basinal facies of southeastern Thuringia (Germany) before and after the Hangenberg Crisis (Devonian–Carboniferous boundary)

“…In Europe, the genus Hadyrhyncha was reported by Halamski and Baliński (2009) in the uppermost Famennian (do VI) of Poland, but this age determination is not sure, as the authors themselves (p. 290) admit that also ammonoids of the Clymenia-"Stufe" had been found in their "bed L". The records from Northern Africa are older: Mottequin et al (2015a) (Algeria, boundary of Platyclymenia-/Clymenia-"Stufe"), Sartenaer (1998b) (Morocco, Clymenia-"Stufe"). The precise age of the Czech type materials from Moravia (Hady Limestone near Brno, "do V-VI") remains unclear without more accurate locality data, e.g., as used by Chlupáč (1966, tab. 2) during his trilobite studies; we need detailed recollecting, underlined by index fossils as ammonoids and/or conodonts.…”

“…fibrosissimum as the predominant species. These rhynchonellides belong to the superfamily Pugnacoidea, of which representatives rank among the most common elements of Devonian-Carboniferous dysaerobic environments (e.g., Bowen et al, 1974;Biernat and Racki, 1986a;Racki, 1989;Alexander, 1994;Sartenaer et al, 1998;Mottequin and Legrand-Blain, 2010;Mottequin et al, 2015a). Palaeobiological implications of the co-occurrence of uniplicate and unisulcate rhynchonellides in Polish contemporaneous succession was discussed by Halamski and Baliński (2009).…”

“…4 around the Devonian-Carboniferous boundary are Tietze (1870), Paeckelmann (1913Paeckelmann ( , 1930Paeckelmann ( , 1931, Schmidt (1924), Grüneberg (1925), Gallwitz (1932), Weyer (1972Weyer ( , 1979, Bartzsch and Weyer (1986), Becker (1988Becker ( , 1996, Bartzsch et al (1998), Sartenaer (1997), Afanasjeva (2002) and Müller (2004). Comparatively few similar studies about such rare aphotic Famennian-Hastarian Brachiopoda were published in other countries: Poland (Biernat, 1983(Biernat, , 1988Racki, 1986a, 1986b;Sartenaer, 1998a;Halamski and Baliński, 2009), Czech Republic (Havlíček, 1979), Russia (Rozman, 1962), Algeria (Mottequin et al, 2015a), Morocco (Sartenaer, 1998a(Sartenaer, , 1998b(Sartenaer, , 1999(Sartenaer, , 2000 and China (Sartenaer and Xu, 1990).…”

Le dévonien supérieur du sahara nord-occidental (algérie) : faciès, environnements et signification géodynamique des calcaires griottes

“…Dans les passées calcaires à nodules micritiques (calcaires mudstones-wackestones à ostracodes), la fréquence des trilobites à vision réduite et/ou aveugles de mer ouverte, probablement de milieu relativement profond (CRÔ-NIER et al, 2013 ;CRÔNIER & FRANÇOIS, 2014 ;DERYCKE et al, 2015), et les brachiopodes, dominés par des formes à coquilles minces, lisses et de petite taille, attestent d'un peuplement de milieu profond dysoxique (MOTTEQUIN et al, 2015).…”

Kellwasser horizons, sea-level changes and brachiopod–coral crises during the late Frasnian in the Namur–Dinant Basin (southern Belgium): a synopsis

“…Among the spiriferids, the early Famennian is mostly characterized by the development of the Cyrtiopsinae that progressively supplanted the Cyrtospiriferinae. The genus Aulacella is sometimes a common element of the epibenthos within ammonoid facies from the Famennian of Morocco and Algeria (Webster et al 2005;Mottequin et al 2015), but also of the Famennian Annulata events beds, notably in Germany and Iran (Becker 1992;Becker et al 2004). It is interesting to note that Aulacella is not recorded within the dark shales of the Matagne Formation as the environment was probably too oxygen-depleted for this genus, which includes some species adapted to deep-water and hypoxic environment.…”