Denise Brice

Brachiopods and Their Auloporid Epibionts in the Devonian of Boulonnais (France): Comparison with Other Associations Globally

From research undertaken on brachiopods encrusted by auloporids at two intervals in the Frasnian (Beaulieu and Ferques Formations) of Boulonnais (France), we conclude that the most important factors influencing encrustation were usually (in decreasing order): size of the host, morphology, feeding currents, shell orientation in vivo and shell ornament. Shell structure (punctate or impunctate) seems not to have influenced the rate of encrustation. In the cases discussed, most but not all auloporids encrusted their hosts in vivo. The most favourable environments for development of both brachiopods and epibionts seem to have been hard bottoms and thin limestone beds alternating with argillaceous beds. The influence of environmental (sedimentologic) conditions is difficult to precisely specify in terms of the development of encrustation, but seems to have played an important role.

Biostratigraphic significance of brachiopods near the Devonian–Carboniferous boundary

The biostratigraphic significance of selected uppermost Famennian (Upper Devonian) and lower Tournaisian (Mississippian) brachiopod genera, belonging to the orders Rhynchonellida (e.g. Araratella ), Spiriferida (e.g. Sphenospira , Prospira ), Spiriferinida ( Syringothyris ) and Productida (except Chonetidina), is discussed. Owing to the difficulties of identifying productidine and strophalosiidine genera, in contrast to rhynchonellides and spiriferides, the biostratigraphic potential of the former has generally been overlooked. Brachiopods flourished in neritic environments that were unfavourable for conodonts and ammonoids. In the absence of the latter traditional marker fossils, they are potentially important for locating the Devonian–Carboniferous boundary in shallow water depositional settings in conjunction with rugose corals and foraminifers. On a worldwide scale, further work is required to reach a better assessment of the aftermath of the Hangenberg biological Crisis on brachiopods, notably in revising the faunas from the classical areas of the Famennian and Tournaisian stages in Western Europe.

Eodmitria, genre nouveau de Brachiopode Cyrtospiriferidaedu Frasnien inférieur et moyen

Resume Un nouveau genre de Brachiopode Spiriferida, Eodmitria, ayant comme espece-type: Spirifer supradisjunctus boloniensis nov. subsp., caracteristique du Frasnien inferieur et moyen, est defini. Il est apparente au genre Dmitria Sidiachenko , 1961 .

Clarification sur la positionsystématique de Spirifer strunianus Gosselet, 1879, brachiopode du Famennien supérieur de l'Avesnois (N. France). Emendation du genre Eobrachythyris Brice, 1971

After a systematic revision, Spirifer strunianus Gosselet, 1879 is re-assigned to the genus ProspiraMaxwell, 1954, Subfamily Prospirinae Carter, 1974. Consequently the genus Eobrachythyris Brice, 1971 is emended. The stratigraphic range of Spirifer strunianus in the Upper Famennian to Etroeungt (type locality in Avesnois) is re-examined.

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

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 .

THE DEVONIAN OF THE HODH AREA (ISLAMIC REPUBLIC OF MAURITANIA): PALEONTOLOGY AND STRATIGRAPHY

Abstract Paleontological study of 16 samples from four sections through the Silurian-Devonian marine deposits of the Hodh region establishes the development of the Middle Devonian and adds to our knowledge of the Paleozoic sequence in the West African platform. Above Silurian deposits locally dated by graptolites from the Llandovery, Devonian shales yield an abundant although low diversity benthic fauna, which is assigned to a Givetian age. The brachiopod fauna shows strong affinity with the NE Americas Realm. Two new species are described, Arcuaminetes deynouxi and Eleutherokomma monodi. The revision of the Devonian fauna of the Hodh area supports: 1) the apparent lack of Lower Devonian deposits; 2) the Givetian age of the Devonian succession; and 3) the strong eastern Americas Realm affinity of the fauna, as previously established for the Mauritanian Adrar area.

Ellesmerhynchia, a new genus of rhynchonelloidea brachiopods from lower (and middle?) devonian of arctic Canada

Abstract Ellesmerhynchia nov. gen. (Rhynchonelloidea Brachiopods) with Camarotoechia s.1. pseudomedea Brice , 1982 as the type species is defined. It occurs typically in the upper part of Blue Fiord Formation, Dalejan in age (= late Emsian), southwestern of Ellesmere Island (Northwest Territories, Canada). The genus occurs also in the Lochkovian of Podolia (Poland and USSR) and perhaps also in Eifelian in Ontario (Canada).