Late Middle Frasnian to Early Famennian (Late Devonian) strophomenid, orthotetid, and athyridid brachiopods from southern Belgium

Abstract

Brachiopods of the orders Strophomenida, Orthotetida, and Athyridida from the late middle Frasnian–early Famennian interval (hassi to triangularis conodont zones) in the Namur-Dinant Basin (southeastern margin of Laurussia; southern Belgium) are described. Nine genera and subgenera represented by 12 species are recognized here. One new genus, Retrorstrophia, and one new species, Douvillina area, are erected. Crinisarina stainbrooki is proposed to solve the homonymy between C. reticulata (Gosselet, 1877) and Cleiothyridina reticulata Stainbrook, 1947, the type species of Crinisarina Cooper and Dutro, 1982. A lectotype is selected and illustrated for C. reticulata. A new name is also proposed for Athyris reticulata Chen and Xu, 2000, which is assigned here to Crinisarina: C. shashishanensis nom. nov. In southern Belgium, the last representatives of the families Douvillinidae and Leptostrophiidae (Strophomenida) are from the Upper rhenana Zone (late Frasnian). Athyridid brachiopods, especially the representatives of the subfamily Cleiothyridininae constituted a significant part of the early Famennian recovery faunas with spiriferids and rhynchonellids, just after the late Frasnian mass extinction.

Biostratigraphic significance of brachiopods near the Devonian–Carboniferous boundary

“…In contrast to other benthic macrofaunas such as the corals (Poty, Denayer & Mottequin, 2011), the post-extinction brachiopod recovery was rapid in the lower Famennian but, despite their great abundance, their diversity was quite low. New cosmopolitan genera appeared at this time particularly among the spire-bearers (athyridides, spiriferides) and the rhynchonellides concomitantly with new species of pre-existing and generally long-ranging orthide and orthotetide genera (Baliński, 2002; Mottequin, 2008 b ). Nevertheless, Devonian brachiopod diversity reached a nadir during the Famennian with 203 genera in comparison with 460 at the Emsian (Curry & Brunton, 2007), but spiriferides and non-chonetidine productides increased significantly during this stage.…”

Lower Famennian (Upper Devonian) rhynchonellide and athyride brachiopods from the South Armenian Block

“…Crinisarina pseudoglobularis n. sp. is very close to C. stainbrooki Mottequin, 2008, known from the lower Famennian of southern Belgium and the USA (Nevada, New Mexico) (see references in Mottequin, 2008); however, C. pseudoglobularis n. sp. differs externally by its more inflated shell, equibiconvex lateral profile, narrower tongue, and by its ornamentation consisting of growth lines that bear solid spine-like outgrowths.…”

“…Order Athyrida Boucot, Johnson, andStaton, 1964 Suborder Athyridina Boucot, Johnson, andStaton, 1964 Superfamily Athyroidea Davidson, 1881 Family Athyridae Davidson, 1881 Subfamily Cleiothyridininae Boucot, 1998 Genus Crinisarina Cooper andDutro, 1982 Type species.-Crinisarina stainbrooki Mottequin, 2008(pro Cleiothyridina reticulata Stainbrook, 1947. Abrahamyan (1957) Ertych section, which is correlated with the Ertych horizon (Fig.…”

“…also represents the first report of the genus Crinisarina in the SAB, and indeed in the entire northern margin of Gondwana, although it cannot be excluded that Crinisarina representatives are present in the Famennian of North Africa (Algeria and Morocco), where taxonomical studies have been mostly dedicated to the rhynchonellides, productidines, and spiriferides, whereas the other elements of the brachiopod faunas received scant attention (see references in Mottequin et al, 2015). Similar to other species of Crinisarina (see discussion in Mottequin, 2008), it is likely that C. pseudoglobularis n. sp. had a preference for soft substrates that were comprised of argillaceous sediments on which it was attached with a thin pedicle.…”

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

“…As the Frasnian–Famennian (F–F) boundary, and thus the position of the Upper Kellwasser Event ( Palmatolepis linguiformis Zone), is not precisely established within the Marhouma Formation, it is difficult to discuss in detail the post-Kellwasser recovery of the brachiopods in this part of the Ougarta Basin. Note that in regions where environmental conditions were more favourable to brachiopods, such as the Namur–Dinant Basin in southern Belgium and the Polish epicontinental basin, their recovery started in the Palmatolepis triangularis Zone very soon after the F–F boundary, in which athyridides, rhynchonellides and spiriferides played a significant role (Baliński 1996, 2002; Mottequin 2008 a , b ). On a worldwide scale, brachiopod diversity declined significantly during Frasnian time with a significant reduction in generic diversity; this was accentuated during Famennian time, possibly due to increasing faunal cosmopolitanism related to major sea-level changes and other parameters that suppressed faunal barriers and allowed interchange between remote areas (e.g.…”